Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/signal.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | * | |
7 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
8 | * | |
9 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
10 | * Changes to use preallocated sigqueue structures | |
11 | * to allow signals to be sent reliably. | |
12 | */ | |
13 | ||
1da177e4 | 14 | #include <linux/slab.h> |
9984de1a | 15 | #include <linux/export.h> |
1da177e4 | 16 | #include <linux/init.h> |
589ee628 | 17 | #include <linux/sched/mm.h> |
8703e8a4 | 18 | #include <linux/sched/user.h> |
b17b0153 | 19 | #include <linux/sched/debug.h> |
29930025 | 20 | #include <linux/sched/task.h> |
68db0cf1 | 21 | #include <linux/sched/task_stack.h> |
32ef5517 | 22 | #include <linux/sched/cputime.h> |
3eb39f47 | 23 | #include <linux/file.h> |
1da177e4 | 24 | #include <linux/fs.h> |
3eb39f47 | 25 | #include <linux/proc_fs.h> |
1da177e4 LT |
26 | #include <linux/tty.h> |
27 | #include <linux/binfmts.h> | |
179899fd | 28 | #include <linux/coredump.h> |
1da177e4 LT |
29 | #include <linux/security.h> |
30 | #include <linux/syscalls.h> | |
31 | #include <linux/ptrace.h> | |
7ed20e1a | 32 | #include <linux/signal.h> |
fba2afaa | 33 | #include <linux/signalfd.h> |
f84d49b2 | 34 | #include <linux/ratelimit.h> |
355f841a | 35 | #include <linux/task_work.h> |
c59ede7b | 36 | #include <linux/capability.h> |
7dfb7103 | 37 | #include <linux/freezer.h> |
84d73786 SB |
38 | #include <linux/pid_namespace.h> |
39 | #include <linux/nsproxy.h> | |
6b550f94 | 40 | #include <linux/user_namespace.h> |
0326f5a9 | 41 | #include <linux/uprobes.h> |
90268439 | 42 | #include <linux/compat.h> |
2b5faa4c | 43 | #include <linux/cn_proc.h> |
52f5684c | 44 | #include <linux/compiler.h> |
31ea70e0 | 45 | #include <linux/posix-timers.h> |
76f969e8 | 46 | #include <linux/cgroup.h> |
b48345aa | 47 | #include <linux/audit.h> |
52f5684c | 48 | |
d1eb650f MH |
49 | #define CREATE_TRACE_POINTS |
50 | #include <trace/events/signal.h> | |
84d73786 | 51 | |
1da177e4 | 52 | #include <asm/param.h> |
7c0f6ba6 | 53 | #include <linux/uaccess.h> |
1da177e4 LT |
54 | #include <asm/unistd.h> |
55 | #include <asm/siginfo.h> | |
d550bbd4 | 56 | #include <asm/cacheflush.h> |
307d522f | 57 | #include <asm/syscall.h> /* for syscall_get_* */ |
1da177e4 LT |
58 | |
59 | /* | |
60 | * SLAB caches for signal bits. | |
61 | */ | |
62 | ||
e18b890b | 63 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 64 | |
f84d49b2 NO |
65 | int print_fatal_signals __read_mostly; |
66 | ||
35de254d | 67 | static void __user *sig_handler(struct task_struct *t, int sig) |
93585eea | 68 | { |
35de254d RM |
69 | return t->sighand->action[sig - 1].sa.sa_handler; |
70 | } | |
93585eea | 71 | |
e4a8b4ef | 72 | static inline bool sig_handler_ignored(void __user *handler, int sig) |
35de254d | 73 | { |
93585eea | 74 | /* Is it explicitly or implicitly ignored? */ |
93585eea | 75 | return handler == SIG_IGN || |
e4a8b4ef | 76 | (handler == SIG_DFL && sig_kernel_ignore(sig)); |
93585eea | 77 | } |
1da177e4 | 78 | |
41aaa481 | 79 | static bool sig_task_ignored(struct task_struct *t, int sig, bool force) |
1da177e4 | 80 | { |
35de254d | 81 | void __user *handler; |
1da177e4 | 82 | |
f008faff ON |
83 | handler = sig_handler(t, sig); |
84 | ||
86989c41 EB |
85 | /* SIGKILL and SIGSTOP may not be sent to the global init */ |
86 | if (unlikely(is_global_init(t) && sig_kernel_only(sig))) | |
87 | return true; | |
88 | ||
f008faff | 89 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && |
ac253850 | 90 | handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
41aaa481 | 91 | return true; |
f008faff | 92 | |
33da8e7c | 93 | /* Only allow kernel generated signals to this kthread */ |
e8b33b8c | 94 | if (unlikely((t->flags & PF_KTHREAD) && |
33da8e7c EB |
95 | (handler == SIG_KTHREAD_KERNEL) && !force)) |
96 | return true; | |
97 | ||
f008faff ON |
98 | return sig_handler_ignored(handler, sig); |
99 | } | |
100 | ||
6a0cdcd7 | 101 | static bool sig_ignored(struct task_struct *t, int sig, bool force) |
f008faff | 102 | { |
1da177e4 LT |
103 | /* |
104 | * Blocked signals are never ignored, since the | |
105 | * signal handler may change by the time it is | |
106 | * unblocked. | |
107 | */ | |
325d22df | 108 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
6a0cdcd7 | 109 | return false; |
1da177e4 | 110 | |
35de254d | 111 | /* |
628c1bcb ON |
112 | * Tracers may want to know about even ignored signal unless it |
113 | * is SIGKILL which can't be reported anyway but can be ignored | |
114 | * by SIGNAL_UNKILLABLE task. | |
35de254d | 115 | */ |
628c1bcb | 116 | if (t->ptrace && sig != SIGKILL) |
6a0cdcd7 | 117 | return false; |
628c1bcb ON |
118 | |
119 | return sig_task_ignored(t, sig, force); | |
1da177e4 LT |
120 | } |
121 | ||
122 | /* | |
123 | * Re-calculate pending state from the set of locally pending | |
124 | * signals, globally pending signals, and blocked signals. | |
125 | */ | |
938696a8 | 126 | static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked) |
1da177e4 LT |
127 | { |
128 | unsigned long ready; | |
129 | long i; | |
130 | ||
131 | switch (_NSIG_WORDS) { | |
132 | default: | |
133 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
134 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
135 | break; | |
136 | ||
137 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
138 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
139 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
140 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
141 | break; | |
142 | ||
143 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
144 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
145 | break; | |
146 | ||
147 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
148 | } | |
149 | return ready != 0; | |
150 | } | |
151 | ||
152 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
153 | ||
09ae854e | 154 | static bool recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 | 155 | { |
76f969e8 | 156 | if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) || |
1da177e4 | 157 | PENDING(&t->pending, &t->blocked) || |
76f969e8 RG |
158 | PENDING(&t->signal->shared_pending, &t->blocked) || |
159 | cgroup_task_frozen(t)) { | |
1da177e4 | 160 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
09ae854e | 161 | return true; |
7bb44ade | 162 | } |
09ae854e | 163 | |
b74d0deb RM |
164 | /* |
165 | * We must never clear the flag in another thread, or in current | |
166 | * when it's possible the current syscall is returning -ERESTART*. | |
167 | * So we don't clear it here, and only callers who know they should do. | |
168 | */ | |
09ae854e | 169 | return false; |
7bb44ade RM |
170 | } |
171 | ||
172 | /* | |
173 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
174 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
175 | */ | |
176 | void recalc_sigpending_and_wake(struct task_struct *t) | |
177 | { | |
178 | if (recalc_sigpending_tsk(t)) | |
179 | signal_wake_up(t, 0); | |
1da177e4 LT |
180 | } |
181 | ||
182 | void recalc_sigpending(void) | |
183 | { | |
8df1947c | 184 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
185 | clear_thread_flag(TIF_SIGPENDING); |
186 | ||
1da177e4 | 187 | } |
fb50f5a4 | 188 | EXPORT_SYMBOL(recalc_sigpending); |
1da177e4 | 189 | |
088fe47c EB |
190 | void calculate_sigpending(void) |
191 | { | |
192 | /* Have any signals or users of TIF_SIGPENDING been delayed | |
193 | * until after fork? | |
194 | */ | |
195 | spin_lock_irq(¤t->sighand->siglock); | |
196 | set_tsk_thread_flag(current, TIF_SIGPENDING); | |
197 | recalc_sigpending(); | |
198 | spin_unlock_irq(¤t->sighand->siglock); | |
199 | } | |
200 | ||
1da177e4 LT |
201 | /* Given the mask, find the first available signal that should be serviced. */ |
202 | ||
a27341cd LT |
203 | #define SYNCHRONOUS_MASK \ |
204 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ | |
a0727e8c | 205 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
a27341cd | 206 | |
fba2afaa | 207 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
208 | { |
209 | unsigned long i, *s, *m, x; | |
210 | int sig = 0; | |
f84d49b2 | 211 | |
1da177e4 LT |
212 | s = pending->signal.sig; |
213 | m = mask->sig; | |
a27341cd LT |
214 | |
215 | /* | |
216 | * Handle the first word specially: it contains the | |
217 | * synchronous signals that need to be dequeued first. | |
218 | */ | |
219 | x = *s &~ *m; | |
220 | if (x) { | |
221 | if (x & SYNCHRONOUS_MASK) | |
222 | x &= SYNCHRONOUS_MASK; | |
223 | sig = ffz(~x) + 1; | |
224 | return sig; | |
225 | } | |
226 | ||
1da177e4 LT |
227 | switch (_NSIG_WORDS) { |
228 | default: | |
a27341cd LT |
229 | for (i = 1; i < _NSIG_WORDS; ++i) { |
230 | x = *++s &~ *++m; | |
231 | if (!x) | |
232 | continue; | |
233 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
234 | break; | |
235 | } | |
1da177e4 LT |
236 | break; |
237 | ||
a27341cd LT |
238 | case 2: |
239 | x = s[1] &~ m[1]; | |
240 | if (!x) | |
1da177e4 | 241 | break; |
a27341cd | 242 | sig = ffz(~x) + _NSIG_BPW + 1; |
1da177e4 LT |
243 | break; |
244 | ||
a27341cd LT |
245 | case 1: |
246 | /* Nothing to do */ | |
1da177e4 LT |
247 | break; |
248 | } | |
f84d49b2 | 249 | |
1da177e4 LT |
250 | return sig; |
251 | } | |
252 | ||
f84d49b2 NO |
253 | static inline void print_dropped_signal(int sig) |
254 | { | |
255 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); | |
256 | ||
257 | if (!print_fatal_signals) | |
258 | return; | |
259 | ||
260 | if (!__ratelimit(&ratelimit_state)) | |
261 | return; | |
262 | ||
747800ef | 263 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
f84d49b2 NO |
264 | current->comm, current->pid, sig); |
265 | } | |
266 | ||
d79fdd6d | 267 | /** |
7dd3db54 | 268 | * task_set_jobctl_pending - set jobctl pending bits |
d79fdd6d | 269 | * @task: target task |
7dd3db54 | 270 | * @mask: pending bits to set |
d79fdd6d | 271 | * |
7dd3db54 TH |
272 | * Clear @mask from @task->jobctl. @mask must be subset of |
273 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | | |
274 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is | |
275 | * cleared. If @task is already being killed or exiting, this function | |
276 | * becomes noop. | |
277 | * | |
278 | * CONTEXT: | |
279 | * Must be called with @task->sighand->siglock held. | |
280 | * | |
281 | * RETURNS: | |
282 | * %true if @mask is set, %false if made noop because @task was dying. | |
283 | */ | |
b76808e6 | 284 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
7dd3db54 TH |
285 | { |
286 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | | |
287 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); | |
288 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); | |
289 | ||
1e4cf0d3 | 290 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) |
7dd3db54 TH |
291 | return false; |
292 | ||
293 | if (mask & JOBCTL_STOP_SIGMASK) | |
294 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; | |
295 | ||
296 | task->jobctl |= mask; | |
297 | return true; | |
298 | } | |
299 | ||
d79fdd6d | 300 | /** |
a8f072c1 | 301 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
d79fdd6d TH |
302 | * @task: target task |
303 | * | |
a8f072c1 TH |
304 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
305 | * Clear it and wake up the ptracer. Note that we don't need any further | |
306 | * locking. @task->siglock guarantees that @task->parent points to the | |
307 | * ptracer. | |
d79fdd6d TH |
308 | * |
309 | * CONTEXT: | |
310 | * Must be called with @task->sighand->siglock held. | |
311 | */ | |
73ddff2b | 312 | void task_clear_jobctl_trapping(struct task_struct *task) |
d79fdd6d | 313 | { |
a8f072c1 TH |
314 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
315 | task->jobctl &= ~JOBCTL_TRAPPING; | |
650226bd | 316 | smp_mb(); /* advised by wake_up_bit() */ |
62c124ff | 317 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
d79fdd6d TH |
318 | } |
319 | } | |
320 | ||
e5c1902e | 321 | /** |
3759a0d9 | 322 | * task_clear_jobctl_pending - clear jobctl pending bits |
e5c1902e | 323 | * @task: target task |
3759a0d9 | 324 | * @mask: pending bits to clear |
e5c1902e | 325 | * |
3759a0d9 TH |
326 | * Clear @mask from @task->jobctl. @mask must be subset of |
327 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other | |
328 | * STOP bits are cleared together. | |
e5c1902e | 329 | * |
6dfca329 TH |
330 | * If clearing of @mask leaves no stop or trap pending, this function calls |
331 | * task_clear_jobctl_trapping(). | |
e5c1902e TH |
332 | * |
333 | * CONTEXT: | |
334 | * Must be called with @task->sighand->siglock held. | |
335 | */ | |
b76808e6 | 336 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
e5c1902e | 337 | { |
3759a0d9 TH |
338 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
339 | ||
340 | if (mask & JOBCTL_STOP_PENDING) | |
341 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; | |
342 | ||
343 | task->jobctl &= ~mask; | |
6dfca329 TH |
344 | |
345 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) | |
346 | task_clear_jobctl_trapping(task); | |
e5c1902e TH |
347 | } |
348 | ||
349 | /** | |
350 | * task_participate_group_stop - participate in a group stop | |
351 | * @task: task participating in a group stop | |
352 | * | |
a8f072c1 | 353 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
39efa3ef | 354 | * Group stop states are cleared and the group stop count is consumed if |
a8f072c1 | 355 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
68d8681e | 356 | * stop, the appropriate `SIGNAL_*` flags are set. |
e5c1902e TH |
357 | * |
358 | * CONTEXT: | |
359 | * Must be called with @task->sighand->siglock held. | |
244056f9 TH |
360 | * |
361 | * RETURNS: | |
362 | * %true if group stop completion should be notified to the parent, %false | |
363 | * otherwise. | |
e5c1902e TH |
364 | */ |
365 | static bool task_participate_group_stop(struct task_struct *task) | |
366 | { | |
367 | struct signal_struct *sig = task->signal; | |
a8f072c1 | 368 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
e5c1902e | 369 | |
a8f072c1 | 370 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
39efa3ef | 371 | |
3759a0d9 | 372 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
e5c1902e TH |
373 | |
374 | if (!consume) | |
375 | return false; | |
376 | ||
377 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) | |
378 | sig->group_stop_count--; | |
379 | ||
244056f9 TH |
380 | /* |
381 | * Tell the caller to notify completion iff we are entering into a | |
382 | * fresh group stop. Read comment in do_signal_stop() for details. | |
383 | */ | |
384 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { | |
2d39b3cd | 385 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
e5c1902e TH |
386 | return true; |
387 | } | |
388 | return false; | |
389 | } | |
390 | ||
924de3b8 EB |
391 | void task_join_group_stop(struct task_struct *task) |
392 | { | |
7b3c36fc ON |
393 | unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK; |
394 | struct signal_struct *sig = current->signal; | |
395 | ||
396 | if (sig->group_stop_count) { | |
397 | sig->group_stop_count++; | |
398 | mask |= JOBCTL_STOP_CONSUME; | |
399 | } else if (!(sig->flags & SIGNAL_STOP_STOPPED)) | |
400 | return; | |
401 | ||
924de3b8 | 402 | /* Have the new thread join an on-going signal group stop */ |
7b3c36fc | 403 | task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING); |
924de3b8 EB |
404 | } |
405 | ||
c69e8d9c DH |
406 | /* |
407 | * allocate a new signal queue record | |
408 | * - this may be called without locks if and only if t == current, otherwise an | |
5aba085e | 409 | * appropriate lock must be held to stop the target task from exiting |
c69e8d9c | 410 | */ |
f84d49b2 | 411 | static struct sigqueue * |
69995ebb TG |
412 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, |
413 | int override_rlimit, const unsigned int sigqueue_flags) | |
1da177e4 LT |
414 | { |
415 | struct sigqueue *q = NULL; | |
d6469690 AG |
416 | struct ucounts *ucounts = NULL; |
417 | long sigpending; | |
1da177e4 | 418 | |
10b1fbdb | 419 | /* |
7cf7db8d TG |
420 | * Protect access to @t credentials. This can go away when all |
421 | * callers hold rcu read lock. | |
fda31c50 LT |
422 | * |
423 | * NOTE! A pending signal will hold on to the user refcount, | |
424 | * and we get/put the refcount only when the sigpending count | |
425 | * changes from/to zero. | |
10b1fbdb | 426 | */ |
7cf7db8d | 427 | rcu_read_lock(); |
d6469690 | 428 | ucounts = task_ucounts(t); |
15bc01ef | 429 | sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
7cf7db8d | 430 | rcu_read_unlock(); |
15bc01ef EB |
431 | if (!sigpending) |
432 | return NULL; | |
f84d49b2 | 433 | |
f3791f4d | 434 | if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { |
b4b27b9e | 435 | q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); |
f84d49b2 NO |
436 | } else { |
437 | print_dropped_signal(sig); | |
438 | } | |
439 | ||
1da177e4 | 440 | if (unlikely(q == NULL)) { |
15bc01ef | 441 | dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
1da177e4 LT |
442 | } else { |
443 | INIT_LIST_HEAD(&q->list); | |
69995ebb | 444 | q->flags = sigqueue_flags; |
d6469690 | 445 | q->ucounts = ucounts; |
1da177e4 | 446 | } |
d84f4f99 | 447 | return q; |
1da177e4 LT |
448 | } |
449 | ||
514a01b8 | 450 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
451 | { |
452 | if (q->flags & SIGQUEUE_PREALLOC) | |
453 | return; | |
15bc01ef EB |
454 | if (q->ucounts) { |
455 | dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING); | |
d6469690 AG |
456 | q->ucounts = NULL; |
457 | } | |
b4b27b9e | 458 | kmem_cache_free(sigqueue_cachep, q); |
1da177e4 LT |
459 | } |
460 | ||
6a14c5c9 | 461 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
462 | { |
463 | struct sigqueue *q; | |
464 | ||
465 | sigemptyset(&queue->signal); | |
466 | while (!list_empty(&queue->list)) { | |
467 | q = list_entry(queue->list.next, struct sigqueue , list); | |
468 | list_del_init(&q->list); | |
469 | __sigqueue_free(q); | |
470 | } | |
471 | } | |
472 | ||
473 | /* | |
9e7c8f8c | 474 | * Flush all pending signals for this kthread. |
1da177e4 | 475 | */ |
c81addc9 | 476 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
477 | { |
478 | unsigned long flags; | |
479 | ||
480 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
9e7c8f8c ON |
481 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
482 | flush_sigqueue(&t->pending); | |
483 | flush_sigqueue(&t->signal->shared_pending); | |
1da177e4 LT |
484 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
485 | } | |
fb50f5a4 | 486 | EXPORT_SYMBOL(flush_signals); |
1da177e4 | 487 | |
baa73d9e | 488 | #ifdef CONFIG_POSIX_TIMERS |
cbaffba1 ON |
489 | static void __flush_itimer_signals(struct sigpending *pending) |
490 | { | |
491 | sigset_t signal, retain; | |
492 | struct sigqueue *q, *n; | |
493 | ||
494 | signal = pending->signal; | |
495 | sigemptyset(&retain); | |
496 | ||
497 | list_for_each_entry_safe(q, n, &pending->list, list) { | |
498 | int sig = q->info.si_signo; | |
499 | ||
500 | if (likely(q->info.si_code != SI_TIMER)) { | |
501 | sigaddset(&retain, sig); | |
502 | } else { | |
503 | sigdelset(&signal, sig); | |
504 | list_del_init(&q->list); | |
505 | __sigqueue_free(q); | |
506 | } | |
507 | } | |
508 | ||
509 | sigorsets(&pending->signal, &signal, &retain); | |
510 | } | |
511 | ||
512 | void flush_itimer_signals(void) | |
513 | { | |
514 | struct task_struct *tsk = current; | |
515 | unsigned long flags; | |
516 | ||
517 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
518 | __flush_itimer_signals(&tsk->pending); | |
519 | __flush_itimer_signals(&tsk->signal->shared_pending); | |
520 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
521 | } | |
baa73d9e | 522 | #endif |
cbaffba1 | 523 | |
10ab825b ON |
524 | void ignore_signals(struct task_struct *t) |
525 | { | |
526 | int i; | |
527 | ||
528 | for (i = 0; i < _NSIG; ++i) | |
529 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
530 | ||
531 | flush_signals(t); | |
532 | } | |
533 | ||
1da177e4 LT |
534 | /* |
535 | * Flush all handlers for a task. | |
536 | */ | |
537 | ||
538 | void | |
539 | flush_signal_handlers(struct task_struct *t, int force_default) | |
540 | { | |
541 | int i; | |
542 | struct k_sigaction *ka = &t->sighand->action[0]; | |
543 | for (i = _NSIG ; i != 0 ; i--) { | |
544 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
545 | ka->sa.sa_handler = SIG_DFL; | |
546 | ka->sa.sa_flags = 0; | |
522cff14 | 547 | #ifdef __ARCH_HAS_SA_RESTORER |
2ca39528 KC |
548 | ka->sa.sa_restorer = NULL; |
549 | #endif | |
1da177e4 LT |
550 | sigemptyset(&ka->sa.sa_mask); |
551 | ka++; | |
552 | } | |
553 | } | |
554 | ||
67a48a24 | 555 | bool unhandled_signal(struct task_struct *tsk, int sig) |
abd4f750 | 556 | { |
445a91d2 | 557 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
b460cbc5 | 558 | if (is_global_init(tsk)) |
67a48a24 CB |
559 | return true; |
560 | ||
445a91d2 | 561 | if (handler != SIG_IGN && handler != SIG_DFL) |
67a48a24 CB |
562 | return false; |
563 | ||
a288eecc TH |
564 | /* if ptraced, let the tracer determine */ |
565 | return !tsk->ptrace; | |
abd4f750 MAS |
566 | } |
567 | ||
ae7795bc | 568 | static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info, |
57db7e4a | 569 | bool *resched_timer) |
1da177e4 LT |
570 | { |
571 | struct sigqueue *q, *first = NULL; | |
1da177e4 | 572 | |
1da177e4 LT |
573 | /* |
574 | * Collect the siginfo appropriate to this signal. Check if | |
575 | * there is another siginfo for the same signal. | |
576 | */ | |
577 | list_for_each_entry(q, &list->list, list) { | |
578 | if (q->info.si_signo == sig) { | |
d4434207 ON |
579 | if (first) |
580 | goto still_pending; | |
1da177e4 LT |
581 | first = q; |
582 | } | |
583 | } | |
d4434207 ON |
584 | |
585 | sigdelset(&list->signal, sig); | |
586 | ||
1da177e4 | 587 | if (first) { |
d4434207 | 588 | still_pending: |
1da177e4 LT |
589 | list_del_init(&first->list); |
590 | copy_siginfo(info, &first->info); | |
57db7e4a EB |
591 | |
592 | *resched_timer = | |
593 | (first->flags & SIGQUEUE_PREALLOC) && | |
594 | (info->si_code == SI_TIMER) && | |
595 | (info->si_sys_private); | |
596 | ||
1da177e4 | 597 | __sigqueue_free(first); |
1da177e4 | 598 | } else { |
5aba085e RD |
599 | /* |
600 | * Ok, it wasn't in the queue. This must be | |
601 | * a fast-pathed signal or we must have been | |
602 | * out of queue space. So zero out the info. | |
1da177e4 | 603 | */ |
faf1f22b | 604 | clear_siginfo(info); |
1da177e4 LT |
605 | info->si_signo = sig; |
606 | info->si_errno = 0; | |
7486e5d9 | 607 | info->si_code = SI_USER; |
1da177e4 LT |
608 | info->si_pid = 0; |
609 | info->si_uid = 0; | |
610 | } | |
1da177e4 LT |
611 | } |
612 | ||
613 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
ae7795bc | 614 | kernel_siginfo_t *info, bool *resched_timer) |
1da177e4 | 615 | { |
27d91e07 | 616 | int sig = next_signal(pending, mask); |
1da177e4 | 617 | |
2e01fabe | 618 | if (sig) |
57db7e4a | 619 | collect_signal(sig, pending, info, resched_timer); |
1da177e4 LT |
620 | return sig; |
621 | } | |
622 | ||
623 | /* | |
5aba085e | 624 | * Dequeue a signal and return the element to the caller, which is |
1da177e4 LT |
625 | * expected to free it. |
626 | * | |
627 | * All callers have to hold the siglock. | |
628 | */ | |
5768d890 EB |
629 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, |
630 | kernel_siginfo_t *info, enum pid_type *type) | |
1da177e4 | 631 | { |
57db7e4a | 632 | bool resched_timer = false; |
c5363d03 | 633 | int signr; |
caec4e8d BH |
634 | |
635 | /* We only dequeue private signals from ourselves, we don't let | |
636 | * signalfd steal them | |
637 | */ | |
5768d890 | 638 | *type = PIDTYPE_PID; |
57db7e4a | 639 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
8bfd9a7a | 640 | if (!signr) { |
5768d890 | 641 | *type = PIDTYPE_TGID; |
1da177e4 | 642 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
57db7e4a | 643 | mask, info, &resched_timer); |
baa73d9e | 644 | #ifdef CONFIG_POSIX_TIMERS |
8bfd9a7a TG |
645 | /* |
646 | * itimer signal ? | |
647 | * | |
648 | * itimers are process shared and we restart periodic | |
649 | * itimers in the signal delivery path to prevent DoS | |
650 | * attacks in the high resolution timer case. This is | |
5aba085e | 651 | * compliant with the old way of self-restarting |
8bfd9a7a TG |
652 | * itimers, as the SIGALRM is a legacy signal and only |
653 | * queued once. Changing the restart behaviour to | |
654 | * restart the timer in the signal dequeue path is | |
655 | * reducing the timer noise on heavy loaded !highres | |
656 | * systems too. | |
657 | */ | |
658 | if (unlikely(signr == SIGALRM)) { | |
659 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
660 | ||
661 | if (!hrtimer_is_queued(tmr) && | |
2456e855 | 662 | tsk->signal->it_real_incr != 0) { |
8bfd9a7a TG |
663 | hrtimer_forward(tmr, tmr->base->get_time(), |
664 | tsk->signal->it_real_incr); | |
665 | hrtimer_restart(tmr); | |
666 | } | |
667 | } | |
baa73d9e | 668 | #endif |
8bfd9a7a | 669 | } |
c5363d03 | 670 | |
b8fceee1 | 671 | recalc_sigpending(); |
c5363d03 PE |
672 | if (!signr) |
673 | return 0; | |
674 | ||
675 | if (unlikely(sig_kernel_stop(signr))) { | |
8bfd9a7a TG |
676 | /* |
677 | * Set a marker that we have dequeued a stop signal. Our | |
678 | * caller might release the siglock and then the pending | |
679 | * stop signal it is about to process is no longer in the | |
680 | * pending bitmasks, but must still be cleared by a SIGCONT | |
681 | * (and overruled by a SIGKILL). So those cases clear this | |
682 | * shared flag after we've set it. Note that this flag may | |
683 | * remain set after the signal we return is ignored or | |
684 | * handled. That doesn't matter because its only purpose | |
685 | * is to alert stop-signal processing code when another | |
686 | * processor has come along and cleared the flag. | |
687 | */ | |
a8f072c1 | 688 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
8bfd9a7a | 689 | } |
baa73d9e | 690 | #ifdef CONFIG_POSIX_TIMERS |
57db7e4a | 691 | if (resched_timer) { |
1da177e4 LT |
692 | /* |
693 | * Release the siglock to ensure proper locking order | |
694 | * of timer locks outside of siglocks. Note, we leave | |
695 | * irqs disabled here, since the posix-timers code is | |
696 | * about to disable them again anyway. | |
697 | */ | |
698 | spin_unlock(&tsk->sighand->siglock); | |
96fe3b07 | 699 | posixtimer_rearm(info); |
1da177e4 | 700 | spin_lock(&tsk->sighand->siglock); |
9943d3ac EB |
701 | |
702 | /* Don't expose the si_sys_private value to userspace */ | |
703 | info->si_sys_private = 0; | |
1da177e4 | 704 | } |
baa73d9e | 705 | #endif |
1da177e4 LT |
706 | return signr; |
707 | } | |
fb50f5a4 | 708 | EXPORT_SYMBOL_GPL(dequeue_signal); |
1da177e4 | 709 | |
7146db33 EB |
710 | static int dequeue_synchronous_signal(kernel_siginfo_t *info) |
711 | { | |
712 | struct task_struct *tsk = current; | |
713 | struct sigpending *pending = &tsk->pending; | |
714 | struct sigqueue *q, *sync = NULL; | |
715 | ||
716 | /* | |
717 | * Might a synchronous signal be in the queue? | |
718 | */ | |
719 | if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) | |
720 | return 0; | |
721 | ||
722 | /* | |
723 | * Return the first synchronous signal in the queue. | |
724 | */ | |
725 | list_for_each_entry(q, &pending->list, list) { | |
7665a47f | 726 | /* Synchronous signals have a positive si_code */ |
7146db33 EB |
727 | if ((q->info.si_code > SI_USER) && |
728 | (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { | |
729 | sync = q; | |
730 | goto next; | |
731 | } | |
732 | } | |
733 | return 0; | |
734 | next: | |
735 | /* | |
736 | * Check if there is another siginfo for the same signal. | |
737 | */ | |
738 | list_for_each_entry_continue(q, &pending->list, list) { | |
739 | if (q->info.si_signo == sync->info.si_signo) | |
740 | goto still_pending; | |
741 | } | |
742 | ||
743 | sigdelset(&pending->signal, sync->info.si_signo); | |
744 | recalc_sigpending(); | |
745 | still_pending: | |
746 | list_del_init(&sync->list); | |
747 | copy_siginfo(info, &sync->info); | |
748 | __sigqueue_free(sync); | |
749 | return info->si_signo; | |
750 | } | |
751 | ||
1da177e4 LT |
752 | /* |
753 | * Tell a process that it has a new active signal.. | |
754 | * | |
755 | * NOTE! we rely on the previous spin_lock to | |
756 | * lock interrupts for us! We can only be called with | |
757 | * "siglock" held, and the local interrupt must | |
758 | * have been disabled when that got acquired! | |
759 | * | |
760 | * No need to set need_resched since signal event passing | |
761 | * goes through ->blocked | |
762 | */ | |
910ffdb1 | 763 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
1da177e4 | 764 | { |
31cae1ea PZ |
765 | lockdep_assert_held(&t->sighand->siglock); |
766 | ||
1da177e4 | 767 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
31cae1ea | 768 | |
1da177e4 | 769 | /* |
910ffdb1 | 770 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
f021a3c2 | 771 | * case. We don't check t->state here because there is a race with it |
1da177e4 LT |
772 | * executing another processor and just now entering stopped state. |
773 | * By using wake_up_state, we ensure the process will wake up and | |
774 | * handle its death signal. | |
775 | */ | |
910ffdb1 | 776 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
1da177e4 LT |
777 | kick_process(t); |
778 | } | |
779 | ||
71fabd5e GA |
780 | /* |
781 | * Remove signals in mask from the pending set and queue. | |
782 | * Returns 1 if any signals were found. | |
783 | * | |
784 | * All callers must be holding the siglock. | |
71fabd5e | 785 | */ |
8f11351e | 786 | static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
71fabd5e GA |
787 | { |
788 | struct sigqueue *q, *n; | |
789 | sigset_t m; | |
790 | ||
791 | sigandsets(&m, mask, &s->signal); | |
792 | if (sigisemptyset(&m)) | |
8f11351e | 793 | return; |
71fabd5e | 794 | |
702a5073 | 795 | sigandnsets(&s->signal, &s->signal, mask); |
71fabd5e GA |
796 | list_for_each_entry_safe(q, n, &s->list, list) { |
797 | if (sigismember(mask, q->info.si_signo)) { | |
798 | list_del_init(&q->list); | |
799 | __sigqueue_free(q); | |
800 | } | |
801 | } | |
71fabd5e | 802 | } |
1da177e4 | 803 | |
ae7795bc | 804 | static inline int is_si_special(const struct kernel_siginfo *info) |
614c517d | 805 | { |
4ff4c31a | 806 | return info <= SEND_SIG_PRIV; |
614c517d ON |
807 | } |
808 | ||
ae7795bc | 809 | static inline bool si_fromuser(const struct kernel_siginfo *info) |
614c517d ON |
810 | { |
811 | return info == SEND_SIG_NOINFO || | |
812 | (!is_si_special(info) && SI_FROMUSER(info)); | |
813 | } | |
814 | ||
39fd3393 SH |
815 | /* |
816 | * called with RCU read lock from check_kill_permission() | |
817 | */ | |
2a9b9094 | 818 | static bool kill_ok_by_cred(struct task_struct *t) |
39fd3393 SH |
819 | { |
820 | const struct cred *cred = current_cred(); | |
821 | const struct cred *tcred = __task_cred(t); | |
822 | ||
2a9b9094 CB |
823 | return uid_eq(cred->euid, tcred->suid) || |
824 | uid_eq(cred->euid, tcred->uid) || | |
825 | uid_eq(cred->uid, tcred->suid) || | |
826 | uid_eq(cred->uid, tcred->uid) || | |
827 | ns_capable(tcred->user_ns, CAP_KILL); | |
39fd3393 SH |
828 | } |
829 | ||
1da177e4 LT |
830 | /* |
831 | * Bad permissions for sending the signal | |
694f690d | 832 | * - the caller must hold the RCU read lock |
1da177e4 | 833 | */ |
ae7795bc | 834 | static int check_kill_permission(int sig, struct kernel_siginfo *info, |
1da177e4 LT |
835 | struct task_struct *t) |
836 | { | |
2e2ba22e | 837 | struct pid *sid; |
3b5e9e53 ON |
838 | int error; |
839 | ||
7ed20e1a | 840 | if (!valid_signal(sig)) |
3b5e9e53 ON |
841 | return -EINVAL; |
842 | ||
614c517d | 843 | if (!si_fromuser(info)) |
3b5e9e53 | 844 | return 0; |
e54dc243 | 845 | |
3b5e9e53 ON |
846 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
847 | if (error) | |
1da177e4 | 848 | return error; |
3b5e9e53 | 849 | |
065add39 | 850 | if (!same_thread_group(current, t) && |
39fd3393 | 851 | !kill_ok_by_cred(t)) { |
2e2ba22e ON |
852 | switch (sig) { |
853 | case SIGCONT: | |
2e2ba22e | 854 | sid = task_session(t); |
2e2ba22e ON |
855 | /* |
856 | * We don't return the error if sid == NULL. The | |
857 | * task was unhashed, the caller must notice this. | |
858 | */ | |
859 | if (!sid || sid == task_session(current)) | |
860 | break; | |
df561f66 | 861 | fallthrough; |
2e2ba22e ON |
862 | default: |
863 | return -EPERM; | |
864 | } | |
865 | } | |
c2f0c7c3 | 866 | |
6b4f3d01 | 867 | return security_task_kill(t, info, sig, NULL); |
1da177e4 LT |
868 | } |
869 | ||
fb1d910c TH |
870 | /** |
871 | * ptrace_trap_notify - schedule trap to notify ptracer | |
872 | * @t: tracee wanting to notify tracer | |
873 | * | |
874 | * This function schedules sticky ptrace trap which is cleared on the next | |
875 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by | |
876 | * ptracer. | |
877 | * | |
544b2c91 TH |
878 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
879 | * ptracer is listening for events, tracee is woken up so that it can | |
880 | * re-trap for the new event. If trapped otherwise, STOP trap will be | |
881 | * eventually taken without returning to userland after the existing traps | |
882 | * are finished by PTRACE_CONT. | |
fb1d910c TH |
883 | * |
884 | * CONTEXT: | |
885 | * Must be called with @task->sighand->siglock held. | |
886 | */ | |
887 | static void ptrace_trap_notify(struct task_struct *t) | |
888 | { | |
889 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); | |
cb3c19c9 | 890 | lockdep_assert_held(&t->sighand->siglock); |
fb1d910c TH |
891 | |
892 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); | |
910ffdb1 | 893 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
fb1d910c TH |
894 | } |
895 | ||
1da177e4 | 896 | /* |
7e695a5e ON |
897 | * Handle magic process-wide effects of stop/continue signals. Unlike |
898 | * the signal actions, these happen immediately at signal-generation | |
1da177e4 LT |
899 | * time regardless of blocking, ignoring, or handling. This does the |
900 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
7e695a5e ON |
901 | * signals. The process stop is done as a signal action for SIG_DFL. |
902 | * | |
903 | * Returns true if the signal should be actually delivered, otherwise | |
904 | * it should be dropped. | |
1da177e4 | 905 | */ |
403bad72 | 906 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
1da177e4 | 907 | { |
ad16a460 | 908 | struct signal_struct *signal = p->signal; |
1da177e4 | 909 | struct task_struct *t; |
9490592f | 910 | sigset_t flush; |
1da177e4 | 911 | |
2f824d4d | 912 | if (signal->flags & SIGNAL_GROUP_EXIT) { |
a0287db0 | 913 | if (signal->core_state) |
403bad72 | 914 | return sig == SIGKILL; |
1da177e4 | 915 | /* |
7e695a5e | 916 | * The process is in the middle of dying, nothing to do. |
1da177e4 | 917 | */ |
7e695a5e | 918 | } else if (sig_kernel_stop(sig)) { |
1da177e4 LT |
919 | /* |
920 | * This is a stop signal. Remove SIGCONT from all queues. | |
921 | */ | |
9490592f | 922 | siginitset(&flush, sigmask(SIGCONT)); |
c09c1441 | 923 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 924 | for_each_thread(p, t) |
c09c1441 | 925 | flush_sigqueue_mask(&flush, &t->pending); |
1da177e4 | 926 | } else if (sig == SIGCONT) { |
fc321d2e | 927 | unsigned int why; |
1da177e4 | 928 | /* |
1deac632 | 929 | * Remove all stop signals from all queues, wake all threads. |
1da177e4 | 930 | */ |
9490592f | 931 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
c09c1441 | 932 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
9490592f | 933 | for_each_thread(p, t) { |
c09c1441 | 934 | flush_sigqueue_mask(&flush, &t->pending); |
3759a0d9 | 935 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
31cae1ea PZ |
936 | if (likely(!(t->ptrace & PT_SEIZED))) { |
937 | t->jobctl &= ~JOBCTL_STOPPED; | |
fb1d910c | 938 | wake_up_state(t, __TASK_STOPPED); |
31cae1ea | 939 | } else |
fb1d910c | 940 | ptrace_trap_notify(t); |
9490592f | 941 | } |
1da177e4 | 942 | |
fc321d2e ON |
943 | /* |
944 | * Notify the parent with CLD_CONTINUED if we were stopped. | |
945 | * | |
946 | * If we were in the middle of a group stop, we pretend it | |
947 | * was already finished, and then continued. Since SIGCHLD | |
948 | * doesn't queue we report only CLD_STOPPED, as if the next | |
949 | * CLD_CONTINUED was dropped. | |
950 | */ | |
951 | why = 0; | |
ad16a460 | 952 | if (signal->flags & SIGNAL_STOP_STOPPED) |
fc321d2e | 953 | why |= SIGNAL_CLD_CONTINUED; |
ad16a460 | 954 | else if (signal->group_stop_count) |
fc321d2e ON |
955 | why |= SIGNAL_CLD_STOPPED; |
956 | ||
957 | if (why) { | |
021e1ae3 | 958 | /* |
ae6d2ed7 | 959 | * The first thread which returns from do_signal_stop() |
021e1ae3 | 960 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
2e58f57d | 961 | * notify its parent. See get_signal(). |
021e1ae3 | 962 | */ |
2d39b3cd | 963 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
ad16a460 ON |
964 | signal->group_stop_count = 0; |
965 | signal->group_exit_code = 0; | |
1da177e4 | 966 | } |
1da177e4 | 967 | } |
7e695a5e | 968 | |
def8cf72 | 969 | return !sig_ignored(p, sig, force); |
1da177e4 LT |
970 | } |
971 | ||
71f11dc0 ON |
972 | /* |
973 | * Test if P wants to take SIG. After we've checked all threads with this, | |
974 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
975 | * blocking SIG were ruled out because they are not running and already | |
976 | * have pending signals. Such threads will dequeue from the shared queue | |
977 | * as soon as they're available, so putting the signal on the shared queue | |
978 | * will be equivalent to sending it to one such thread. | |
979 | */ | |
acd14e62 | 980 | static inline bool wants_signal(int sig, struct task_struct *p) |
71f11dc0 ON |
981 | { |
982 | if (sigismember(&p->blocked, sig)) | |
acd14e62 CB |
983 | return false; |
984 | ||
71f11dc0 | 985 | if (p->flags & PF_EXITING) |
acd14e62 CB |
986 | return false; |
987 | ||
71f11dc0 | 988 | if (sig == SIGKILL) |
acd14e62 CB |
989 | return true; |
990 | ||
71f11dc0 | 991 | if (task_is_stopped_or_traced(p)) |
acd14e62 CB |
992 | return false; |
993 | ||
5c251e9d | 994 | return task_curr(p) || !task_sigpending(p); |
71f11dc0 ON |
995 | } |
996 | ||
07296149 | 997 | static void complete_signal(int sig, struct task_struct *p, enum pid_type type) |
71f11dc0 ON |
998 | { |
999 | struct signal_struct *signal = p->signal; | |
1000 | struct task_struct *t; | |
1001 | ||
1002 | /* | |
1003 | * Now find a thread we can wake up to take the signal off the queue. | |
1004 | * | |
1005 | * If the main thread wants the signal, it gets first crack. | |
1006 | * Probably the least surprising to the average bear. | |
1007 | */ | |
1008 | if (wants_signal(sig, p)) | |
1009 | t = p; | |
07296149 | 1010 | else if ((type == PIDTYPE_PID) || thread_group_empty(p)) |
71f11dc0 ON |
1011 | /* |
1012 | * There is just one thread and it does not need to be woken. | |
1013 | * It will dequeue unblocked signals before it runs again. | |
1014 | */ | |
1015 | return; | |
1016 | else { | |
1017 | /* | |
1018 | * Otherwise try to find a suitable thread. | |
1019 | */ | |
1020 | t = signal->curr_target; | |
1021 | while (!wants_signal(sig, t)) { | |
1022 | t = next_thread(t); | |
1023 | if (t == signal->curr_target) | |
1024 | /* | |
1025 | * No thread needs to be woken. | |
1026 | * Any eligible threads will see | |
1027 | * the signal in the queue soon. | |
1028 | */ | |
1029 | return; | |
1030 | } | |
1031 | signal->curr_target = t; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * Found a killable thread. If the signal will be fatal, | |
1036 | * then start taking the whole group down immediately. | |
1037 | */ | |
fae5fa44 | 1038 | if (sig_fatal(p, sig) && |
7ba03471 | 1039 | (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) && |
71f11dc0 | 1040 | !sigismember(&t->real_blocked, sig) && |
42691579 | 1041 | (sig == SIGKILL || !p->ptrace)) { |
71f11dc0 ON |
1042 | /* |
1043 | * This signal will be fatal to the whole group. | |
1044 | */ | |
1045 | if (!sig_kernel_coredump(sig)) { | |
1046 | /* | |
1047 | * Start a group exit and wake everybody up. | |
1048 | * This way we don't have other threads | |
1049 | * running and doing things after a slower | |
1050 | * thread has the fatal signal pending. | |
1051 | */ | |
1052 | signal->flags = SIGNAL_GROUP_EXIT; | |
1053 | signal->group_exit_code = sig; | |
1054 | signal->group_stop_count = 0; | |
1055 | t = p; | |
1056 | do { | |
6dfca329 | 1057 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
71f11dc0 ON |
1058 | sigaddset(&t->pending.signal, SIGKILL); |
1059 | signal_wake_up(t, 1); | |
1060 | } while_each_thread(p, t); | |
1061 | return; | |
1062 | } | |
1063 | } | |
1064 | ||
1065 | /* | |
1066 | * The signal is already in the shared-pending queue. | |
1067 | * Tell the chosen thread to wake up and dequeue it. | |
1068 | */ | |
1069 | signal_wake_up(t, sig == SIGKILL); | |
1070 | return; | |
1071 | } | |
1072 | ||
a19e2c01 | 1073 | static inline bool legacy_queue(struct sigpending *signals, int sig) |
af7fff9c PE |
1074 | { |
1075 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
1076 | } | |
1077 | ||
157cc181 EB |
1078 | static int __send_signal_locked(int sig, struct kernel_siginfo *info, |
1079 | struct task_struct *t, enum pid_type type, bool force) | |
1da177e4 | 1080 | { |
2ca3515a | 1081 | struct sigpending *pending; |
6e65acba | 1082 | struct sigqueue *q; |
7a0aeb14 | 1083 | int override_rlimit; |
6c303d3a | 1084 | int ret = 0, result; |
0a16b607 | 1085 | |
cb3c19c9 | 1086 | lockdep_assert_held(&t->sighand->siglock); |
921cf9f6 | 1087 | |
6c303d3a | 1088 | result = TRACE_SIGNAL_IGNORED; |
8ad23dea | 1089 | if (!prepare_signal(sig, t, force)) |
6c303d3a | 1090 | goto ret; |
2ca3515a | 1091 | |
5a883cee | 1092 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
2acb024d PE |
1093 | /* |
1094 | * Short-circuit ignored signals and support queuing | |
1095 | * exactly one non-rt signal, so that we can get more | |
1096 | * detailed information about the cause of the signal. | |
1097 | */ | |
6c303d3a | 1098 | result = TRACE_SIGNAL_ALREADY_PENDING; |
7e695a5e | 1099 | if (legacy_queue(pending, sig)) |
6c303d3a ON |
1100 | goto ret; |
1101 | ||
1102 | result = TRACE_SIGNAL_DELIVERED; | |
1da177e4 | 1103 | /* |
a692933a | 1104 | * Skip useless siginfo allocation for SIGKILL and kernel threads. |
1da177e4 | 1105 | */ |
e8b33b8c | 1106 | if ((sig == SIGKILL) || (t->flags & PF_KTHREAD)) |
1da177e4 LT |
1107 | goto out_set; |
1108 | ||
5aba085e RD |
1109 | /* |
1110 | * Real-time signals must be queued if sent by sigqueue, or | |
1111 | * some other real-time mechanism. It is implementation | |
1112 | * defined whether kill() does so. We attempt to do so, on | |
1113 | * the principle of least surprise, but since kill is not | |
1114 | * allowed to fail with EAGAIN when low on memory we just | |
1115 | * make sure at least one signal gets delivered and don't | |
1116 | * pass on the info struct. | |
1117 | */ | |
7a0aeb14 VN |
1118 | if (sig < SIGRTMIN) |
1119 | override_rlimit = (is_si_special(info) || info->si_code >= 0); | |
1120 | else | |
1121 | override_rlimit = 0; | |
1122 | ||
69995ebb TG |
1123 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0); |
1124 | ||
1da177e4 | 1125 | if (q) { |
2ca3515a | 1126 | list_add_tail(&q->list, &pending->list); |
1da177e4 | 1127 | switch ((unsigned long) info) { |
b67a1b9e | 1128 | case (unsigned long) SEND_SIG_NOINFO: |
faf1f22b | 1129 | clear_siginfo(&q->info); |
1da177e4 LT |
1130 | q->info.si_signo = sig; |
1131 | q->info.si_errno = 0; | |
1132 | q->info.si_code = SI_USER; | |
9cd4fd10 | 1133 | q->info.si_pid = task_tgid_nr_ns(current, |
09bca05c | 1134 | task_active_pid_ns(t)); |
7a0cf094 EB |
1135 | rcu_read_lock(); |
1136 | q->info.si_uid = | |
1137 | from_kuid_munged(task_cred_xxx(t, user_ns), | |
1138 | current_uid()); | |
1139 | rcu_read_unlock(); | |
1da177e4 | 1140 | break; |
b67a1b9e | 1141 | case (unsigned long) SEND_SIG_PRIV: |
faf1f22b | 1142 | clear_siginfo(&q->info); |
1da177e4 LT |
1143 | q->info.si_signo = sig; |
1144 | q->info.si_errno = 0; | |
1145 | q->info.si_code = SI_KERNEL; | |
1146 | q->info.si_pid = 0; | |
1147 | q->info.si_uid = 0; | |
1148 | break; | |
1149 | default: | |
1150 | copy_siginfo(&q->info, info); | |
1151 | break; | |
1152 | } | |
8917bef3 EB |
1153 | } else if (!is_si_special(info) && |
1154 | sig >= SIGRTMIN && info->si_code != SI_USER) { | |
1155 | /* | |
1156 | * Queue overflow, abort. We may abort if the | |
1157 | * signal was rt and sent by user using something | |
1158 | * other than kill(). | |
1159 | */ | |
1160 | result = TRACE_SIGNAL_OVERFLOW_FAIL; | |
1161 | ret = -EAGAIN; | |
1162 | goto ret; | |
1163 | } else { | |
1164 | /* | |
1165 | * This is a silent loss of information. We still | |
1166 | * send the signal, but the *info bits are lost. | |
1167 | */ | |
1168 | result = TRACE_SIGNAL_LOSE_INFO; | |
1da177e4 LT |
1169 | } |
1170 | ||
1171 | out_set: | |
53c30337 | 1172 | signalfd_notify(t, sig); |
2ca3515a | 1173 | sigaddset(&pending->signal, sig); |
c3ad2c3b EB |
1174 | |
1175 | /* Let multiprocess signals appear after on-going forks */ | |
1176 | if (type > PIDTYPE_TGID) { | |
1177 | struct multiprocess_signals *delayed; | |
1178 | hlist_for_each_entry(delayed, &t->signal->multiprocess, node) { | |
1179 | sigset_t *signal = &delayed->signal; | |
1180 | /* Can't queue both a stop and a continue signal */ | |
1181 | if (sig == SIGCONT) | |
1182 | sigdelsetmask(signal, SIG_KERNEL_STOP_MASK); | |
1183 | else if (sig_kernel_stop(sig)) | |
1184 | sigdelset(signal, SIGCONT); | |
1185 | sigaddset(signal, sig); | |
1186 | } | |
1187 | } | |
1188 | ||
07296149 | 1189 | complete_signal(sig, t, type); |
6c303d3a | 1190 | ret: |
5a883cee | 1191 | trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result); |
6c303d3a | 1192 | return ret; |
1da177e4 LT |
1193 | } |
1194 | ||
7a0cf094 EB |
1195 | static inline bool has_si_pid_and_uid(struct kernel_siginfo *info) |
1196 | { | |
1197 | bool ret = false; | |
1198 | switch (siginfo_layout(info->si_signo, info->si_code)) { | |
1199 | case SIL_KILL: | |
1200 | case SIL_CHLD: | |
1201 | case SIL_RT: | |
1202 | ret = true; | |
1203 | break; | |
1204 | case SIL_TIMER: | |
1205 | case SIL_POLL: | |
1206 | case SIL_FAULT: | |
9abcabe3 | 1207 | case SIL_FAULT_TRAPNO: |
7a0cf094 EB |
1208 | case SIL_FAULT_MCEERR: |
1209 | case SIL_FAULT_BNDERR: | |
1210 | case SIL_FAULT_PKUERR: | |
f4ac7302 | 1211 | case SIL_FAULT_PERF_EVENT: |
7a0cf094 EB |
1212 | case SIL_SYS: |
1213 | ret = false; | |
1214 | break; | |
1215 | } | |
1216 | return ret; | |
1217 | } | |
1218 | ||
157cc181 EB |
1219 | int send_signal_locked(int sig, struct kernel_siginfo *info, |
1220 | struct task_struct *t, enum pid_type type) | |
7978b567 | 1221 | { |
8ad23dea EB |
1222 | /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */ |
1223 | bool force = false; | |
921cf9f6 | 1224 | |
8ad23dea EB |
1225 | if (info == SEND_SIG_NOINFO) { |
1226 | /* Force if sent from an ancestor pid namespace */ | |
1227 | force = !task_pid_nr_ns(current, task_active_pid_ns(t)); | |
1228 | } else if (info == SEND_SIG_PRIV) { | |
1229 | /* Don't ignore kernel generated signals */ | |
1230 | force = true; | |
1231 | } else if (has_si_pid_and_uid(info)) { | |
1232 | /* SIGKILL and SIGSTOP is special or has ids */ | |
7a0cf094 EB |
1233 | struct user_namespace *t_user_ns; |
1234 | ||
1235 | rcu_read_lock(); | |
1236 | t_user_ns = task_cred_xxx(t, user_ns); | |
1237 | if (current_user_ns() != t_user_ns) { | |
1238 | kuid_t uid = make_kuid(current_user_ns(), info->si_uid); | |
1239 | info->si_uid = from_kuid_munged(t_user_ns, uid); | |
1240 | } | |
1241 | rcu_read_unlock(); | |
921cf9f6 | 1242 | |
8ad23dea EB |
1243 | /* A kernel generated signal? */ |
1244 | force = (info->si_code == SI_KERNEL); | |
1245 | ||
1246 | /* From an ancestor pid namespace? */ | |
1247 | if (!task_pid_nr_ns(current, task_active_pid_ns(t))) { | |
7a0cf094 | 1248 | info->si_pid = 0; |
8ad23dea EB |
1249 | force = true; |
1250 | } | |
7a0cf094 | 1251 | } |
157cc181 | 1252 | return __send_signal_locked(sig, info, t, type, force); |
7978b567 SB |
1253 | } |
1254 | ||
4aaefee5 | 1255 | static void print_fatal_signal(int signr) |
45807a1d | 1256 | { |
4aaefee5 | 1257 | struct pt_regs *regs = signal_pt_regs(); |
747800ef | 1258 | pr_info("potentially unexpected fatal signal %d.\n", signr); |
45807a1d | 1259 | |
ca5cd877 | 1260 | #if defined(__i386__) && !defined(__arch_um__) |
747800ef | 1261 | pr_info("code at %08lx: ", regs->ip); |
45807a1d IM |
1262 | { |
1263 | int i; | |
1264 | for (i = 0; i < 16; i++) { | |
1265 | unsigned char insn; | |
1266 | ||
b45c6e76 AK |
1267 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
1268 | break; | |
747800ef | 1269 | pr_cont("%02x ", insn); |
45807a1d IM |
1270 | } |
1271 | } | |
747800ef | 1272 | pr_cont("\n"); |
45807a1d | 1273 | #endif |
3a9f84d3 | 1274 | preempt_disable(); |
45807a1d | 1275 | show_regs(regs); |
3a9f84d3 | 1276 | preempt_enable(); |
45807a1d IM |
1277 | } |
1278 | ||
1279 | static int __init setup_print_fatal_signals(char *str) | |
1280 | { | |
1281 | get_option (&str, &print_fatal_signals); | |
1282 | ||
1283 | return 1; | |
1284 | } | |
1285 | ||
1286 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 | 1287 | |
ae7795bc | 1288 | int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, |
40b3b025 | 1289 | enum pid_type type) |
4a30debf ON |
1290 | { |
1291 | unsigned long flags; | |
1292 | int ret = -ESRCH; | |
1293 | ||
1294 | if (lock_task_sighand(p, &flags)) { | |
157cc181 | 1295 | ret = send_signal_locked(sig, info, p, type); |
4a30debf ON |
1296 | unlock_task_sighand(p, &flags); |
1297 | } | |
1298 | ||
1299 | return ret; | |
1300 | } | |
1301 | ||
e349d945 EB |
1302 | enum sig_handler { |
1303 | HANDLER_CURRENT, /* If reachable use the current handler */ | |
1304 | HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */ | |
1305 | HANDLER_EXIT, /* Only visible as the process exit code */ | |
1306 | }; | |
1307 | ||
1da177e4 LT |
1308 | /* |
1309 | * Force a signal that the process can't ignore: if necessary | |
1310 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
1311 | * |
1312 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
1313 | * since we do not want to have a signal handler that was blocked | |
1314 | * be invoked when user space had explicitly blocked it. | |
1315 | * | |
80fe728d ON |
1316 | * We don't want to have recursive SIGSEGV's etc, for example, |
1317 | * that is why we also clear SIGNAL_UNKILLABLE. | |
1da177e4 | 1318 | */ |
59c0e696 | 1319 | static int |
e349d945 EB |
1320 | force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t, |
1321 | enum sig_handler handler) | |
1da177e4 LT |
1322 | { |
1323 | unsigned long int flags; | |
ae74c3b6 LT |
1324 | int ret, blocked, ignored; |
1325 | struct k_sigaction *action; | |
59c0e696 | 1326 | int sig = info->si_signo; |
1da177e4 LT |
1327 | |
1328 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
1329 | action = &t->sighand->action[sig-1]; |
1330 | ignored = action->sa.sa_handler == SIG_IGN; | |
1331 | blocked = sigismember(&t->blocked, sig); | |
e349d945 | 1332 | if (blocked || ignored || (handler != HANDLER_CURRENT)) { |
ae74c3b6 | 1333 | action->sa.sa_handler = SIG_DFL; |
e349d945 EB |
1334 | if (handler == HANDLER_EXIT) |
1335 | action->sa.sa_flags |= SA_IMMUTABLE; | |
ae74c3b6 LT |
1336 | if (blocked) { |
1337 | sigdelset(&t->blocked, sig); | |
7bb44ade | 1338 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 1339 | } |
1da177e4 | 1340 | } |
eb61b591 JI |
1341 | /* |
1342 | * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect | |
5c72263e | 1343 | * debugging to leave init killable. But HANDLER_EXIT is always fatal. |
eb61b591 | 1344 | */ |
5c72263e KC |
1345 | if (action->sa.sa_handler == SIG_DFL && |
1346 | (!t->ptrace || (handler == HANDLER_EXIT))) | |
80fe728d | 1347 | t->signal->flags &= ~SIGNAL_UNKILLABLE; |
157cc181 | 1348 | ret = send_signal_locked(sig, info, t, PIDTYPE_PID); |
1da177e4 LT |
1349 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
1350 | ||
1351 | return ret; | |
1352 | } | |
1353 | ||
a89e9b8a | 1354 | int force_sig_info(struct kernel_siginfo *info) |
59c0e696 | 1355 | { |
e349d945 | 1356 | return force_sig_info_to_task(info, current, HANDLER_CURRENT); |
59c0e696 EB |
1357 | } |
1358 | ||
1da177e4 LT |
1359 | /* |
1360 | * Nuke all other threads in the group. | |
1361 | */ | |
09faef11 | 1362 | int zap_other_threads(struct task_struct *p) |
1da177e4 | 1363 | { |
09faef11 ON |
1364 | struct task_struct *t = p; |
1365 | int count = 0; | |
1da177e4 | 1366 | |
1da177e4 LT |
1367 | p->signal->group_stop_count = 0; |
1368 | ||
09faef11 | 1369 | while_each_thread(p, t) { |
6dfca329 | 1370 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
09faef11 ON |
1371 | count++; |
1372 | ||
1373 | /* Don't bother with already dead threads */ | |
1da177e4 LT |
1374 | if (t->exit_state) |
1375 | continue; | |
1da177e4 | 1376 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
1377 | signal_wake_up(t, 1); |
1378 | } | |
09faef11 ON |
1379 | |
1380 | return count; | |
1da177e4 LT |
1381 | } |
1382 | ||
b8ed374e NK |
1383 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
1384 | unsigned long *flags) | |
f63ee72e ON |
1385 | { |
1386 | struct sighand_struct *sighand; | |
1387 | ||
59dc6f3c | 1388 | rcu_read_lock(); |
f63ee72e ON |
1389 | for (;;) { |
1390 | sighand = rcu_dereference(tsk->sighand); | |
59dc6f3c | 1391 | if (unlikely(sighand == NULL)) |
f63ee72e | 1392 | break; |
59dc6f3c | 1393 | |
392809b2 ON |
1394 | /* |
1395 | * This sighand can be already freed and even reused, but | |
5f0d5a3a | 1396 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
392809b2 ON |
1397 | * initializes ->siglock: this slab can't go away, it has |
1398 | * the same object type, ->siglock can't be reinitialized. | |
1399 | * | |
1400 | * We need to ensure that tsk->sighand is still the same | |
1401 | * after we take the lock, we can race with de_thread() or | |
1402 | * __exit_signal(). In the latter case the next iteration | |
1403 | * must see ->sighand == NULL. | |
1404 | */ | |
59dc6f3c | 1405 | spin_lock_irqsave(&sighand->siglock, *flags); |
913292c9 | 1406 | if (likely(sighand == rcu_access_pointer(tsk->sighand))) |
f63ee72e | 1407 | break; |
59dc6f3c | 1408 | spin_unlock_irqrestore(&sighand->siglock, *flags); |
f63ee72e | 1409 | } |
59dc6f3c | 1410 | rcu_read_unlock(); |
f63ee72e ON |
1411 | |
1412 | return sighand; | |
1413 | } | |
1414 | ||
a5dec9f8 FW |
1415 | #ifdef CONFIG_LOCKDEP |
1416 | void lockdep_assert_task_sighand_held(struct task_struct *task) | |
1417 | { | |
1418 | struct sighand_struct *sighand; | |
1419 | ||
1420 | rcu_read_lock(); | |
1421 | sighand = rcu_dereference(task->sighand); | |
1422 | if (sighand) | |
1423 | lockdep_assert_held(&sighand->siglock); | |
1424 | else | |
1425 | WARN_ON_ONCE(1); | |
1426 | rcu_read_unlock(); | |
1427 | } | |
1428 | #endif | |
1429 | ||
c69e8d9c DH |
1430 | /* |
1431 | * send signal info to all the members of a group | |
c69e8d9c | 1432 | */ |
ae7795bc EB |
1433 | int group_send_sig_info(int sig, struct kernel_siginfo *info, |
1434 | struct task_struct *p, enum pid_type type) | |
1da177e4 | 1435 | { |
694f690d DH |
1436 | int ret; |
1437 | ||
1438 | rcu_read_lock(); | |
1439 | ret = check_kill_permission(sig, info, p); | |
1440 | rcu_read_unlock(); | |
f63ee72e | 1441 | |
4a30debf | 1442 | if (!ret && sig) |
40b3b025 | 1443 | ret = do_send_sig_info(sig, info, p, type); |
1da177e4 LT |
1444 | |
1445 | return ret; | |
1446 | } | |
1447 | ||
1448 | /* | |
146a505d | 1449 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 | 1450 | * control characters do (^C, ^Z etc) |
c69e8d9c | 1451 | * - the caller must hold at least a readlock on tasklist_lock |
1da177e4 | 1452 | */ |
ae7795bc | 1453 | int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1454 | { |
1455 | struct task_struct *p = NULL; | |
1456 | int retval, success; | |
1457 | ||
1da177e4 LT |
1458 | success = 0; |
1459 | retval = -ESRCH; | |
c4b92fc1 | 1460 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
01024980 | 1461 | int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID); |
1da177e4 LT |
1462 | success |= !err; |
1463 | retval = err; | |
c4b92fc1 | 1464 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1465 | return success ? 0 : retval; |
1466 | } | |
1467 | ||
ae7795bc | 1468 | int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) |
1da177e4 | 1469 | { |
d36174bc | 1470 | int error = -ESRCH; |
1da177e4 LT |
1471 | struct task_struct *p; |
1472 | ||
eca1a089 PM |
1473 | for (;;) { |
1474 | rcu_read_lock(); | |
1475 | p = pid_task(pid, PIDTYPE_PID); | |
1476 | if (p) | |
01024980 | 1477 | error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); |
eca1a089 PM |
1478 | rcu_read_unlock(); |
1479 | if (likely(!p || error != -ESRCH)) | |
1480 | return error; | |
6ca25b55 | 1481 | |
eca1a089 PM |
1482 | /* |
1483 | * The task was unhashed in between, try again. If it | |
1484 | * is dead, pid_task() will return NULL, if we race with | |
1485 | * de_thread() it will find the new leader. | |
1486 | */ | |
1487 | } | |
1da177e4 LT |
1488 | } |
1489 | ||
ae7795bc | 1490 | static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) |
c4b92fc1 EB |
1491 | { |
1492 | int error; | |
1493 | rcu_read_lock(); | |
b488893a | 1494 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1495 | rcu_read_unlock(); |
1496 | return error; | |
1497 | } | |
1498 | ||
bb17fcca CB |
1499 | static inline bool kill_as_cred_perm(const struct cred *cred, |
1500 | struct task_struct *target) | |
d178bc3a SH |
1501 | { |
1502 | const struct cred *pcred = __task_cred(target); | |
bb17fcca CB |
1503 | |
1504 | return uid_eq(cred->euid, pcred->suid) || | |
1505 | uid_eq(cred->euid, pcred->uid) || | |
1506 | uid_eq(cred->uid, pcred->suid) || | |
1507 | uid_eq(cred->uid, pcred->uid); | |
d178bc3a SH |
1508 | } |
1509 | ||
70f1b0d3 EB |
1510 | /* |
1511 | * The usb asyncio usage of siginfo is wrong. The glibc support | |
1512 | * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT. | |
1513 | * AKA after the generic fields: | |
1514 | * kernel_pid_t si_pid; | |
1515 | * kernel_uid32_t si_uid; | |
1516 | * sigval_t si_value; | |
1517 | * | |
1518 | * Unfortunately when usb generates SI_ASYNCIO it assumes the layout | |
1519 | * after the generic fields is: | |
1520 | * void __user *si_addr; | |
1521 | * | |
1522 | * This is a practical problem when there is a 64bit big endian kernel | |
1523 | * and a 32bit userspace. As the 32bit address will encoded in the low | |
1524 | * 32bits of the pointer. Those low 32bits will be stored at higher | |
1525 | * address than appear in a 32 bit pointer. So userspace will not | |
1526 | * see the address it was expecting for it's completions. | |
1527 | * | |
1528 | * There is nothing in the encoding that can allow | |
1529 | * copy_siginfo_to_user32 to detect this confusion of formats, so | |
1530 | * handle this by requiring the caller of kill_pid_usb_asyncio to | |
1531 | * notice when this situration takes place and to store the 32bit | |
1532 | * pointer in sival_int, instead of sival_addr of the sigval_t addr | |
1533 | * parameter. | |
1534 | */ | |
1535 | int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, | |
1536 | struct pid *pid, const struct cred *cred) | |
46113830 | 1537 | { |
70f1b0d3 | 1538 | struct kernel_siginfo info; |
46113830 | 1539 | struct task_struct *p; |
14d8c9f3 | 1540 | unsigned long flags; |
70f1b0d3 EB |
1541 | int ret = -EINVAL; |
1542 | ||
eaec2b0b ZL |
1543 | if (!valid_signal(sig)) |
1544 | return ret; | |
1545 | ||
70f1b0d3 EB |
1546 | clear_siginfo(&info); |
1547 | info.si_signo = sig; | |
1548 | info.si_errno = errno; | |
1549 | info.si_code = SI_ASYNCIO; | |
1550 | *((sigval_t *)&info.si_pid) = addr; | |
46113830 | 1551 | |
14d8c9f3 | 1552 | rcu_read_lock(); |
2425c08b | 1553 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1554 | if (!p) { |
1555 | ret = -ESRCH; | |
1556 | goto out_unlock; | |
1557 | } | |
70f1b0d3 | 1558 | if (!kill_as_cred_perm(cred, p)) { |
46113830 HW |
1559 | ret = -EPERM; |
1560 | goto out_unlock; | |
1561 | } | |
70f1b0d3 | 1562 | ret = security_task_kill(p, &info, sig, cred); |
8f95dc58 DQ |
1563 | if (ret) |
1564 | goto out_unlock; | |
14d8c9f3 TG |
1565 | |
1566 | if (sig) { | |
1567 | if (lock_task_sighand(p, &flags)) { | |
157cc181 | 1568 | ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false); |
14d8c9f3 TG |
1569 | unlock_task_sighand(p, &flags); |
1570 | } else | |
1571 | ret = -ESRCH; | |
46113830 HW |
1572 | } |
1573 | out_unlock: | |
14d8c9f3 | 1574 | rcu_read_unlock(); |
46113830 HW |
1575 | return ret; |
1576 | } | |
70f1b0d3 | 1577 | EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio); |
1da177e4 LT |
1578 | |
1579 | /* | |
1580 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1581 | * | |
1582 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1583 | * is probably wrong. Should make it like BSD or SYSV. | |
1584 | */ | |
1585 | ||
ae7795bc | 1586 | static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid) |
1da177e4 | 1587 | { |
8d42db18 | 1588 | int ret; |
d5df763b | 1589 | |
3075afdf ZL |
1590 | if (pid > 0) |
1591 | return kill_proc_info(sig, info, pid); | |
d5df763b | 1592 | |
4ea77014 | 1593 | /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
1594 | if (pid == INT_MIN) | |
1595 | return -ESRCH; | |
1596 | ||
d5df763b PE |
1597 | read_lock(&tasklist_lock); |
1598 | if (pid != -1) { | |
1599 | ret = __kill_pgrp_info(sig, info, | |
1600 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1601 | } else { | |
1da177e4 LT |
1602 | int retval = 0, count = 0; |
1603 | struct task_struct * p; | |
1604 | ||
1da177e4 | 1605 | for_each_process(p) { |
d25141a8 SB |
1606 | if (task_pid_vnr(p) > 1 && |
1607 | !same_thread_group(p, current)) { | |
01024980 EB |
1608 | int err = group_send_sig_info(sig, info, p, |
1609 | PIDTYPE_MAX); | |
1da177e4 LT |
1610 | ++count; |
1611 | if (err != -EPERM) | |
1612 | retval = err; | |
1613 | } | |
1614 | } | |
8d42db18 | 1615 | ret = count ? retval : -ESRCH; |
1da177e4 | 1616 | } |
d5df763b PE |
1617 | read_unlock(&tasklist_lock); |
1618 | ||
8d42db18 | 1619 | return ret; |
1da177e4 LT |
1620 | } |
1621 | ||
1622 | /* | |
1623 | * These are for backward compatibility with the rest of the kernel source. | |
1624 | */ | |
1625 | ||
ae7795bc | 1626 | int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p) |
1da177e4 | 1627 | { |
1da177e4 LT |
1628 | /* |
1629 | * Make sure legacy kernel users don't send in bad values | |
1630 | * (normal paths check this in check_kill_permission). | |
1631 | */ | |
7ed20e1a | 1632 | if (!valid_signal(sig)) |
1da177e4 LT |
1633 | return -EINVAL; |
1634 | ||
40b3b025 | 1635 | return do_send_sig_info(sig, info, p, PIDTYPE_PID); |
1da177e4 | 1636 | } |
fb50f5a4 | 1637 | EXPORT_SYMBOL(send_sig_info); |
1da177e4 | 1638 | |
b67a1b9e ON |
1639 | #define __si_special(priv) \ |
1640 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1641 | ||
1da177e4 LT |
1642 | int |
1643 | send_sig(int sig, struct task_struct *p, int priv) | |
1644 | { | |
b67a1b9e | 1645 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 | 1646 | } |
fb50f5a4 | 1647 | EXPORT_SYMBOL(send_sig); |
1da177e4 | 1648 | |
3cf5d076 | 1649 | void force_sig(int sig) |
1da177e4 | 1650 | { |
ffafd23b EB |
1651 | struct kernel_siginfo info; |
1652 | ||
1653 | clear_siginfo(&info); | |
1654 | info.si_signo = sig; | |
1655 | info.si_errno = 0; | |
1656 | info.si_code = SI_KERNEL; | |
1657 | info.si_pid = 0; | |
1658 | info.si_uid = 0; | |
a89e9b8a | 1659 | force_sig_info(&info); |
1da177e4 | 1660 | } |
fb50f5a4 | 1661 | EXPORT_SYMBOL(force_sig); |
1da177e4 | 1662 | |
26d5badb EB |
1663 | void force_fatal_sig(int sig) |
1664 | { | |
1665 | struct kernel_siginfo info; | |
1666 | ||
1667 | clear_siginfo(&info); | |
1668 | info.si_signo = sig; | |
1669 | info.si_errno = 0; | |
1670 | info.si_code = SI_KERNEL; | |
1671 | info.si_pid = 0; | |
1672 | info.si_uid = 0; | |
e349d945 | 1673 | force_sig_info_to_task(&info, current, HANDLER_SIG_DFL); |
26d5badb EB |
1674 | } |
1675 | ||
fcb116bc EB |
1676 | void force_exit_sig(int sig) |
1677 | { | |
1678 | struct kernel_siginfo info; | |
1679 | ||
1680 | clear_siginfo(&info); | |
1681 | info.si_signo = sig; | |
1682 | info.si_errno = 0; | |
1683 | info.si_code = SI_KERNEL; | |
1684 | info.si_pid = 0; | |
1685 | info.si_uid = 0; | |
1686 | force_sig_info_to_task(&info, current, HANDLER_EXIT); | |
1687 | } | |
1688 | ||
1da177e4 LT |
1689 | /* |
1690 | * When things go south during signal handling, we | |
1691 | * will force a SIGSEGV. And if the signal that caused | |
1692 | * the problem was already a SIGSEGV, we'll want to | |
1693 | * make sure we don't even try to deliver the signal.. | |
1694 | */ | |
cb44c9a0 | 1695 | void force_sigsegv(int sig) |
1da177e4 | 1696 | { |
26d5badb EB |
1697 | if (sig == SIGSEGV) |
1698 | force_fatal_sig(SIGSEGV); | |
1699 | else | |
1700 | force_sig(SIGSEGV); | |
1da177e4 LT |
1701 | } |
1702 | ||
91ca180d | 1703 | int force_sig_fault_to_task(int sig, int code, void __user *addr |
f8ec6601 EB |
1704 | ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) |
1705 | , struct task_struct *t) | |
1706 | { | |
ae7795bc | 1707 | struct kernel_siginfo info; |
f8ec6601 EB |
1708 | |
1709 | clear_siginfo(&info); | |
1710 | info.si_signo = sig; | |
1711 | info.si_errno = 0; | |
1712 | info.si_code = code; | |
1713 | info.si_addr = addr; | |
f8ec6601 EB |
1714 | #ifdef __ia64__ |
1715 | info.si_imm = imm; | |
1716 | info.si_flags = flags; | |
1717 | info.si_isr = isr; | |
1718 | #endif | |
e349d945 | 1719 | return force_sig_info_to_task(&info, t, HANDLER_CURRENT); |
f8ec6601 EB |
1720 | } |
1721 | ||
91ca180d | 1722 | int force_sig_fault(int sig, int code, void __user *addr |
2e1661d2 | 1723 | ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)) |
91ca180d EB |
1724 | { |
1725 | return force_sig_fault_to_task(sig, code, addr | |
2e1661d2 | 1726 | ___ARCH_SI_IA64(imm, flags, isr), current); |
f8ec6601 EB |
1727 | } |
1728 | ||
1729 | int send_sig_fault(int sig, int code, void __user *addr | |
f8ec6601 EB |
1730 | ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr) |
1731 | , struct task_struct *t) | |
1732 | { | |
ae7795bc | 1733 | struct kernel_siginfo info; |
f8ec6601 EB |
1734 | |
1735 | clear_siginfo(&info); | |
1736 | info.si_signo = sig; | |
1737 | info.si_errno = 0; | |
1738 | info.si_code = code; | |
1739 | info.si_addr = addr; | |
f8ec6601 EB |
1740 | #ifdef __ia64__ |
1741 | info.si_imm = imm; | |
1742 | info.si_flags = flags; | |
1743 | info.si_isr = isr; | |
1744 | #endif | |
1745 | return send_sig_info(info.si_signo, &info, t); | |
1746 | } | |
1747 | ||
f8eac901 | 1748 | int force_sig_mceerr(int code, void __user *addr, short lsb) |
38246735 | 1749 | { |
ae7795bc | 1750 | struct kernel_siginfo info; |
38246735 EB |
1751 | |
1752 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); | |
1753 | clear_siginfo(&info); | |
1754 | info.si_signo = SIGBUS; | |
1755 | info.si_errno = 0; | |
1756 | info.si_code = code; | |
1757 | info.si_addr = addr; | |
1758 | info.si_addr_lsb = lsb; | |
a89e9b8a | 1759 | return force_sig_info(&info); |
38246735 EB |
1760 | } |
1761 | ||
1762 | int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t) | |
1763 | { | |
ae7795bc | 1764 | struct kernel_siginfo info; |
38246735 EB |
1765 | |
1766 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); | |
1767 | clear_siginfo(&info); | |
1768 | info.si_signo = SIGBUS; | |
1769 | info.si_errno = 0; | |
1770 | info.si_code = code; | |
1771 | info.si_addr = addr; | |
1772 | info.si_addr_lsb = lsb; | |
1773 | return send_sig_info(info.si_signo, &info, t); | |
1774 | } | |
1775 | EXPORT_SYMBOL(send_sig_mceerr); | |
38246735 | 1776 | |
38246735 EB |
1777 | int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper) |
1778 | { | |
ae7795bc | 1779 | struct kernel_siginfo info; |
38246735 EB |
1780 | |
1781 | clear_siginfo(&info); | |
1782 | info.si_signo = SIGSEGV; | |
1783 | info.si_errno = 0; | |
1784 | info.si_code = SEGV_BNDERR; | |
1785 | info.si_addr = addr; | |
1786 | info.si_lower = lower; | |
1787 | info.si_upper = upper; | |
a89e9b8a | 1788 | return force_sig_info(&info); |
38246735 | 1789 | } |
38246735 EB |
1790 | |
1791 | #ifdef SEGV_PKUERR | |
1792 | int force_sig_pkuerr(void __user *addr, u32 pkey) | |
1793 | { | |
ae7795bc | 1794 | struct kernel_siginfo info; |
38246735 EB |
1795 | |
1796 | clear_siginfo(&info); | |
1797 | info.si_signo = SIGSEGV; | |
1798 | info.si_errno = 0; | |
1799 | info.si_code = SEGV_PKUERR; | |
1800 | info.si_addr = addr; | |
1801 | info.si_pkey = pkey; | |
a89e9b8a | 1802 | return force_sig_info(&info); |
38246735 EB |
1803 | } |
1804 | #endif | |
f8ec6601 | 1805 | |
78ed93d7 | 1806 | int send_sig_perf(void __user *addr, u32 type, u64 sig_data) |
af5eeab7 EB |
1807 | { |
1808 | struct kernel_siginfo info; | |
1809 | ||
1810 | clear_siginfo(&info); | |
0683b531 EB |
1811 | info.si_signo = SIGTRAP; |
1812 | info.si_errno = 0; | |
1813 | info.si_code = TRAP_PERF; | |
1814 | info.si_addr = addr; | |
1815 | info.si_perf_data = sig_data; | |
1816 | info.si_perf_type = type; | |
1817 | ||
78ed93d7 ME |
1818 | /* |
1819 | * Signals generated by perf events should not terminate the whole | |
1820 | * process if SIGTRAP is blocked, however, delivering the signal | |
1821 | * asynchronously is better than not delivering at all. But tell user | |
1822 | * space if the signal was asynchronous, so it can clearly be | |
1823 | * distinguished from normal synchronous ones. | |
1824 | */ | |
1825 | info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ? | |
1826 | TRAP_PERF_FLAG_ASYNC : | |
1827 | 0; | |
1828 | ||
1829 | return send_sig_info(info.si_signo, &info, current); | |
af5eeab7 EB |
1830 | } |
1831 | ||
307d522f EB |
1832 | /** |
1833 | * force_sig_seccomp - signals the task to allow in-process syscall emulation | |
1834 | * @syscall: syscall number to send to userland | |
1835 | * @reason: filter-supplied reason code to send to userland (via si_errno) | |
6410349e | 1836 | * @force_coredump: true to trigger a coredump |
307d522f EB |
1837 | * |
1838 | * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info. | |
1839 | */ | |
1840 | int force_sig_seccomp(int syscall, int reason, bool force_coredump) | |
1841 | { | |
1842 | struct kernel_siginfo info; | |
1843 | ||
1844 | clear_siginfo(&info); | |
1845 | info.si_signo = SIGSYS; | |
1846 | info.si_code = SYS_SECCOMP; | |
1847 | info.si_call_addr = (void __user *)KSTK_EIP(current); | |
1848 | info.si_errno = reason; | |
1849 | info.si_arch = syscall_get_arch(current); | |
1850 | info.si_syscall = syscall; | |
e349d945 EB |
1851 | return force_sig_info_to_task(&info, current, |
1852 | force_coredump ? HANDLER_EXIT : HANDLER_CURRENT); | |
307d522f EB |
1853 | } |
1854 | ||
f71dd7dc EB |
1855 | /* For the crazy architectures that include trap information in |
1856 | * the errno field, instead of an actual errno value. | |
1857 | */ | |
1858 | int force_sig_ptrace_errno_trap(int errno, void __user *addr) | |
1859 | { | |
ae7795bc | 1860 | struct kernel_siginfo info; |
f71dd7dc EB |
1861 | |
1862 | clear_siginfo(&info); | |
1863 | info.si_signo = SIGTRAP; | |
1864 | info.si_errno = errno; | |
1865 | info.si_code = TRAP_HWBKPT; | |
1866 | info.si_addr = addr; | |
a89e9b8a | 1867 | return force_sig_info(&info); |
f71dd7dc EB |
1868 | } |
1869 | ||
2c9f7eaf EB |
1870 | /* For the rare architectures that include trap information using |
1871 | * si_trapno. | |
1872 | */ | |
1873 | int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno) | |
1874 | { | |
1875 | struct kernel_siginfo info; | |
1876 | ||
1877 | clear_siginfo(&info); | |
1878 | info.si_signo = sig; | |
1879 | info.si_errno = 0; | |
1880 | info.si_code = code; | |
1881 | info.si_addr = addr; | |
1882 | info.si_trapno = trapno; | |
1883 | return force_sig_info(&info); | |
1884 | } | |
1885 | ||
7de5f68d EB |
1886 | /* For the rare architectures that include trap information using |
1887 | * si_trapno. | |
1888 | */ | |
1889 | int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno, | |
1890 | struct task_struct *t) | |
1891 | { | |
1892 | struct kernel_siginfo info; | |
1893 | ||
1894 | clear_siginfo(&info); | |
1895 | info.si_signo = sig; | |
1896 | info.si_errno = 0; | |
1897 | info.si_code = code; | |
1898 | info.si_addr = addr; | |
1899 | info.si_trapno = trapno; | |
1900 | return send_sig_info(info.si_signo, &info, t); | |
1901 | } | |
1902 | ||
c4b92fc1 EB |
1903 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1904 | { | |
146a505d PE |
1905 | int ret; |
1906 | ||
1907 | read_lock(&tasklist_lock); | |
1908 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1909 | read_unlock(&tasklist_lock); | |
1910 | ||
1911 | return ret; | |
c4b92fc1 EB |
1912 | } |
1913 | EXPORT_SYMBOL(kill_pgrp); | |
1914 | ||
1915 | int kill_pid(struct pid *pid, int sig, int priv) | |
1916 | { | |
1917 | return kill_pid_info(sig, __si_special(priv), pid); | |
1918 | } | |
1919 | EXPORT_SYMBOL(kill_pid); | |
1920 | ||
1da177e4 LT |
1921 | /* |
1922 | * These functions support sending signals using preallocated sigqueue | |
1923 | * structures. This is needed "because realtime applications cannot | |
1924 | * afford to lose notifications of asynchronous events, like timer | |
5aba085e | 1925 | * expirations or I/O completions". In the case of POSIX Timers |
1da177e4 LT |
1926 | * we allocate the sigqueue structure from the timer_create. If this |
1927 | * allocation fails we are able to report the failure to the application | |
1928 | * with an EAGAIN error. | |
1929 | */ | |
1da177e4 LT |
1930 | struct sigqueue *sigqueue_alloc(void) |
1931 | { | |
69995ebb | 1932 | return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC); |
1da177e4 LT |
1933 | } |
1934 | ||
1935 | void sigqueue_free(struct sigqueue *q) | |
1936 | { | |
1937 | unsigned long flags; | |
60187d27 ON |
1938 | spinlock_t *lock = ¤t->sighand->siglock; |
1939 | ||
1da177e4 LT |
1940 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1941 | /* | |
c8e85b4f ON |
1942 | * We must hold ->siglock while testing q->list |
1943 | * to serialize with collect_signal() or with | |
da7978b0 | 1944 | * __exit_signal()->flush_sigqueue(). |
1da177e4 | 1945 | */ |
60187d27 | 1946 | spin_lock_irqsave(lock, flags); |
c8e85b4f ON |
1947 | q->flags &= ~SIGQUEUE_PREALLOC; |
1948 | /* | |
1949 | * If it is queued it will be freed when dequeued, | |
1950 | * like the "regular" sigqueue. | |
1951 | */ | |
60187d27 | 1952 | if (!list_empty(&q->list)) |
c8e85b4f | 1953 | q = NULL; |
60187d27 ON |
1954 | spin_unlock_irqrestore(lock, flags); |
1955 | ||
c8e85b4f ON |
1956 | if (q) |
1957 | __sigqueue_free(q); | |
1da177e4 LT |
1958 | } |
1959 | ||
24122c7f | 1960 | int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) |
9e3bd6c3 | 1961 | { |
e62e6650 | 1962 | int sig = q->info.si_signo; |
2ca3515a | 1963 | struct sigpending *pending; |
24122c7f | 1964 | struct task_struct *t; |
e62e6650 | 1965 | unsigned long flags; |
163566f6 | 1966 | int ret, result; |
2ca3515a | 1967 | |
4cd4b6d4 | 1968 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e62e6650 ON |
1969 | |
1970 | ret = -1; | |
24122c7f EB |
1971 | rcu_read_lock(); |
1972 | t = pid_task(pid, type); | |
1973 | if (!t || !likely(lock_task_sighand(t, &flags))) | |
e62e6650 ON |
1974 | goto ret; |
1975 | ||
7e695a5e | 1976 | ret = 1; /* the signal is ignored */ |
163566f6 | 1977 | result = TRACE_SIGNAL_IGNORED; |
def8cf72 | 1978 | if (!prepare_signal(sig, t, false)) |
e62e6650 ON |
1979 | goto out; |
1980 | ||
1981 | ret = 0; | |
9e3bd6c3 PE |
1982 | if (unlikely(!list_empty(&q->list))) { |
1983 | /* | |
1984 | * If an SI_TIMER entry is already queue just increment | |
1985 | * the overrun count. | |
1986 | */ | |
9e3bd6c3 PE |
1987 | BUG_ON(q->info.si_code != SI_TIMER); |
1988 | q->info.si_overrun++; | |
163566f6 | 1989 | result = TRACE_SIGNAL_ALREADY_PENDING; |
e62e6650 | 1990 | goto out; |
9e3bd6c3 | 1991 | } |
ba661292 | 1992 | q->info.si_overrun = 0; |
9e3bd6c3 | 1993 | |
9e3bd6c3 | 1994 | signalfd_notify(t, sig); |
24122c7f | 1995 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
9e3bd6c3 PE |
1996 | list_add_tail(&q->list, &pending->list); |
1997 | sigaddset(&pending->signal, sig); | |
07296149 | 1998 | complete_signal(sig, t, type); |
163566f6 | 1999 | result = TRACE_SIGNAL_DELIVERED; |
e62e6650 | 2000 | out: |
24122c7f | 2001 | trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result); |
e62e6650 ON |
2002 | unlock_task_sighand(t, &flags); |
2003 | ret: | |
24122c7f | 2004 | rcu_read_unlock(); |
e62e6650 | 2005 | return ret; |
9e3bd6c3 PE |
2006 | } |
2007 | ||
b53b0b9d JFG |
2008 | static void do_notify_pidfd(struct task_struct *task) |
2009 | { | |
2010 | struct pid *pid; | |
2011 | ||
1caf7d50 | 2012 | WARN_ON(task->exit_state == 0); |
b53b0b9d JFG |
2013 | pid = task_pid(task); |
2014 | wake_up_all(&pid->wait_pidfd); | |
2015 | } | |
2016 | ||
1da177e4 LT |
2017 | /* |
2018 | * Let a parent know about the death of a child. | |
2019 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
2b2a1ff6 | 2020 | * |
53c8f9f1 ON |
2021 | * Returns true if our parent ignored us and so we've switched to |
2022 | * self-reaping. | |
1da177e4 | 2023 | */ |
53c8f9f1 | 2024 | bool do_notify_parent(struct task_struct *tsk, int sig) |
1da177e4 | 2025 | { |
ae7795bc | 2026 | struct kernel_siginfo info; |
1da177e4 LT |
2027 | unsigned long flags; |
2028 | struct sighand_struct *psig; | |
53c8f9f1 | 2029 | bool autoreap = false; |
bde8285e | 2030 | u64 utime, stime; |
1da177e4 | 2031 | |
a382f8fe | 2032 | WARN_ON_ONCE(sig == -1); |
1da177e4 | 2033 | |
a382f8fe LT |
2034 | /* do_notify_parent_cldstop should have been called instead. */ |
2035 | WARN_ON_ONCE(task_is_stopped_or_traced(tsk)); | |
1da177e4 | 2036 | |
a382f8fe | 2037 | WARN_ON_ONCE(!tsk->ptrace && |
1da177e4 LT |
2038 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
2039 | ||
b53b0b9d JFG |
2040 | /* Wake up all pidfd waiters */ |
2041 | do_notify_pidfd(tsk); | |
2042 | ||
b6e238dc ON |
2043 | if (sig != SIGCHLD) { |
2044 | /* | |
2045 | * This is only possible if parent == real_parent. | |
2046 | * Check if it has changed security domain. | |
2047 | */ | |
d1e7fd64 | 2048 | if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id)) |
b6e238dc ON |
2049 | sig = SIGCHLD; |
2050 | } | |
2051 | ||
faf1f22b | 2052 | clear_siginfo(&info); |
1da177e4 LT |
2053 | info.si_signo = sig; |
2054 | info.si_errno = 0; | |
b488893a | 2055 | /* |
32084504 EB |
2056 | * We are under tasklist_lock here so our parent is tied to |
2057 | * us and cannot change. | |
b488893a | 2058 | * |
32084504 EB |
2059 | * task_active_pid_ns will always return the same pid namespace |
2060 | * until a task passes through release_task. | |
b488893a PE |
2061 | * |
2062 | * write_lock() currently calls preempt_disable() which is the | |
2063 | * same as rcu_read_lock(), but according to Oleg, this is not | |
2064 | * correct to rely on this | |
2065 | */ | |
2066 | rcu_read_lock(); | |
32084504 | 2067 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
54ba47ed EB |
2068 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
2069 | task_uid(tsk)); | |
b488893a PE |
2070 | rcu_read_unlock(); |
2071 | ||
bde8285e FW |
2072 | task_cputime(tsk, &utime, &stime); |
2073 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); | |
2074 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); | |
1da177e4 LT |
2075 | |
2076 | info.si_status = tsk->exit_code & 0x7f; | |
2077 | if (tsk->exit_code & 0x80) | |
2078 | info.si_code = CLD_DUMPED; | |
2079 | else if (tsk->exit_code & 0x7f) | |
2080 | info.si_code = CLD_KILLED; | |
2081 | else { | |
2082 | info.si_code = CLD_EXITED; | |
2083 | info.si_status = tsk->exit_code >> 8; | |
2084 | } | |
2085 | ||
2086 | psig = tsk->parent->sighand; | |
2087 | spin_lock_irqsave(&psig->siglock, flags); | |
d21142ec | 2088 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
2089 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
2090 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
2091 | /* | |
2092 | * We are exiting and our parent doesn't care. POSIX.1 | |
2093 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
2094 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
2095 | * automatically and not left for our parent's wait4 call. | |
2096 | * Rather than having the parent do it as a magic kind of | |
2097 | * signal handler, we just set this to tell do_exit that we | |
2098 | * can be cleaned up without becoming a zombie. Note that | |
2099 | * we still call __wake_up_parent in this case, because a | |
2100 | * blocked sys_wait4 might now return -ECHILD. | |
2101 | * | |
2102 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
2103 | * is implementation-defined: we do (if you don't want | |
2104 | * it, just use SIG_IGN instead). | |
2105 | */ | |
53c8f9f1 | 2106 | autoreap = true; |
1da177e4 | 2107 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
53c8f9f1 | 2108 | sig = 0; |
1da177e4 | 2109 | } |
61e713bd EB |
2110 | /* |
2111 | * Send with __send_signal as si_pid and si_uid are in the | |
2112 | * parent's namespaces. | |
2113 | */ | |
53c8f9f1 | 2114 | if (valid_signal(sig) && sig) |
157cc181 | 2115 | __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false); |
1da177e4 LT |
2116 | __wake_up_parent(tsk, tsk->parent); |
2117 | spin_unlock_irqrestore(&psig->siglock, flags); | |
2b2a1ff6 | 2118 | |
53c8f9f1 | 2119 | return autoreap; |
1da177e4 LT |
2120 | } |
2121 | ||
75b95953 TH |
2122 | /** |
2123 | * do_notify_parent_cldstop - notify parent of stopped/continued state change | |
2124 | * @tsk: task reporting the state change | |
2125 | * @for_ptracer: the notification is for ptracer | |
2126 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report | |
2127 | * | |
2128 | * Notify @tsk's parent that the stopped/continued state has changed. If | |
2129 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. | |
2130 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. | |
2131 | * | |
2132 | * CONTEXT: | |
2133 | * Must be called with tasklist_lock at least read locked. | |
2134 | */ | |
2135 | static void do_notify_parent_cldstop(struct task_struct *tsk, | |
2136 | bool for_ptracer, int why) | |
1da177e4 | 2137 | { |
ae7795bc | 2138 | struct kernel_siginfo info; |
1da177e4 | 2139 | unsigned long flags; |
bc505a47 | 2140 | struct task_struct *parent; |
1da177e4 | 2141 | struct sighand_struct *sighand; |
bde8285e | 2142 | u64 utime, stime; |
1da177e4 | 2143 | |
75b95953 | 2144 | if (for_ptracer) { |
bc505a47 | 2145 | parent = tsk->parent; |
75b95953 | 2146 | } else { |
bc505a47 ON |
2147 | tsk = tsk->group_leader; |
2148 | parent = tsk->real_parent; | |
2149 | } | |
2150 | ||
faf1f22b | 2151 | clear_siginfo(&info); |
1da177e4 LT |
2152 | info.si_signo = SIGCHLD; |
2153 | info.si_errno = 0; | |
b488893a | 2154 | /* |
5aba085e | 2155 | * see comment in do_notify_parent() about the following 4 lines |
b488893a PE |
2156 | */ |
2157 | rcu_read_lock(); | |
17cf22c3 | 2158 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
54ba47ed | 2159 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
b488893a PE |
2160 | rcu_read_unlock(); |
2161 | ||
bde8285e FW |
2162 | task_cputime(tsk, &utime, &stime); |
2163 | info.si_utime = nsec_to_clock_t(utime); | |
2164 | info.si_stime = nsec_to_clock_t(stime); | |
1da177e4 LT |
2165 | |
2166 | info.si_code = why; | |
2167 | switch (why) { | |
2168 | case CLD_CONTINUED: | |
2169 | info.si_status = SIGCONT; | |
2170 | break; | |
2171 | case CLD_STOPPED: | |
2172 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
2173 | break; | |
2174 | case CLD_TRAPPED: | |
2175 | info.si_status = tsk->exit_code & 0x7f; | |
2176 | break; | |
2177 | default: | |
2178 | BUG(); | |
2179 | } | |
2180 | ||
2181 | sighand = parent->sighand; | |
2182 | spin_lock_irqsave(&sighand->siglock, flags); | |
2183 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
2184 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
e71ba124 | 2185 | send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID); |
1da177e4 LT |
2186 | /* |
2187 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
2188 | */ | |
2189 | __wake_up_parent(tsk, parent); | |
2190 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
2191 | } | |
2192 | ||
2193 | /* | |
2194 | * This must be called with current->sighand->siglock held. | |
2195 | * | |
2196 | * This should be the path for all ptrace stops. | |
2197 | * We always set current->last_siginfo while stopped here. | |
2198 | * That makes it a way to test a stopped process for | |
2199 | * being ptrace-stopped vs being job-control-stopped. | |
2200 | * | |
6487d1da EB |
2201 | * Returns the signal the ptracer requested the code resume |
2202 | * with. If the code did not stop because the tracer is gone, | |
2203 | * the stop signal remains unchanged unless clear_code. | |
1da177e4 | 2204 | */ |
57b6de08 EB |
2205 | static int ptrace_stop(int exit_code, int why, unsigned long message, |
2206 | kernel_siginfo_t *info) | |
b8401150 NK |
2207 | __releases(¤t->sighand->siglock) |
2208 | __acquires(¤t->sighand->siglock) | |
1da177e4 | 2209 | { |
ceb6bd67 TH |
2210 | bool gstop_done = false; |
2211 | ||
4f627af8 | 2212 | if (arch_ptrace_stop_needed()) { |
1a669c2f RM |
2213 | /* |
2214 | * The arch code has something special to do before a | |
2215 | * ptrace stop. This is allowed to block, e.g. for faults | |
2216 | * on user stack pages. We can't keep the siglock while | |
2217 | * calling arch_ptrace_stop, so we must release it now. | |
2218 | * To preserve proper semantics, we must do this before | |
2219 | * any signal bookkeeping like checking group_stop_count. | |
1a669c2f RM |
2220 | */ |
2221 | spin_unlock_irq(¤t->sighand->siglock); | |
4f627af8 | 2222 | arch_ptrace_stop(); |
1a669c2f | 2223 | spin_lock_irq(¤t->sighand->siglock); |
1a669c2f RM |
2224 | } |
2225 | ||
7d613f9f | 2226 | /* |
2500ad1c EB |
2227 | * After this point ptrace_signal_wake_up or signal_wake_up |
2228 | * will clear TASK_TRACED if ptrace_unlink happens or a fatal | |
2229 | * signal comes in. Handle previous ptrace_unlinks and fatal | |
2230 | * signals here to prevent ptrace_stop sleeping in schedule. | |
7d613f9f | 2231 | */ |
2500ad1c | 2232 | if (!current->ptrace || __fatal_signal_pending(current)) |
57b6de08 EB |
2233 | return exit_code; |
2234 | ||
b5bf9a90 | 2235 | set_special_state(TASK_TRACED); |
31cae1ea | 2236 | current->jobctl |= JOBCTL_TRACED; |
b5bf9a90 | 2237 | |
1da177e4 | 2238 | /* |
81be24b8 TH |
2239 | * We're committing to trapping. TRACED should be visible before |
2240 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). | |
2241 | * Also, transition to TRACED and updates to ->jobctl should be | |
2242 | * atomic with respect to siglock and should be done after the arch | |
2243 | * hook as siglock is released and regrabbed across it. | |
b5bf9a90 PZ |
2244 | * |
2245 | * TRACER TRACEE | |
2246 | * | |
2247 | * ptrace_attach() | |
2248 | * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) | |
2249 | * do_wait() | |
2250 | * set_current_state() smp_wmb(); | |
2251 | * ptrace_do_wait() | |
2252 | * wait_task_stopped() | |
2253 | * task_stopped_code() | |
2254 | * [L] task_is_traced() [S] task_clear_jobctl_trapping(); | |
1da177e4 | 2255 | */ |
b5bf9a90 | 2256 | smp_wmb(); |
1da177e4 | 2257 | |
336d4b81 | 2258 | current->ptrace_message = message; |
1da177e4 LT |
2259 | current->last_siginfo = info; |
2260 | current->exit_code = exit_code; | |
2261 | ||
d79fdd6d | 2262 | /* |
0ae8ce1c TH |
2263 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
2264 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered | |
73ddff2b TH |
2265 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
2266 | * could be clear now. We act as if SIGCONT is received after | |
2267 | * TASK_TRACED is entered - ignore it. | |
d79fdd6d | 2268 | */ |
a8f072c1 | 2269 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
ceb6bd67 | 2270 | gstop_done = task_participate_group_stop(current); |
d79fdd6d | 2271 | |
fb1d910c | 2272 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
73ddff2b | 2273 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
fb1d910c TH |
2274 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
2275 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); | |
73ddff2b | 2276 | |
81be24b8 | 2277 | /* entering a trap, clear TRAPPING */ |
a8f072c1 | 2278 | task_clear_jobctl_trapping(current); |
d79fdd6d | 2279 | |
1da177e4 LT |
2280 | spin_unlock_irq(¤t->sighand->siglock); |
2281 | read_lock(&tasklist_lock); | |
57b6de08 EB |
2282 | /* |
2283 | * Notify parents of the stop. | |
2284 | * | |
2285 | * While ptraced, there are two parents - the ptracer and | |
2286 | * the real_parent of the group_leader. The ptracer should | |
2287 | * know about every stop while the real parent is only | |
2288 | * interested in the completion of group stop. The states | |
2289 | * for the two don't interact with each other. Notify | |
2290 | * separately unless they're gonna be duplicates. | |
2291 | */ | |
2292 | if (current->ptrace) | |
ceb6bd67 | 2293 | do_notify_parent_cldstop(current, true, why); |
57b6de08 EB |
2294 | if (gstop_done && (!current->ptrace || ptrace_reparented(current))) |
2295 | do_notify_parent_cldstop(current, false, why); | |
ceb6bd67 | 2296 | |
57b6de08 EB |
2297 | /* |
2298 | * Don't want to allow preemption here, because | |
2299 | * sys_ptrace() needs this task to be inactive. | |
2300 | * | |
2301 | * XXX: implement read_unlock_no_resched(). | |
2302 | */ | |
2303 | preempt_disable(); | |
2304 | read_unlock(&tasklist_lock); | |
2305 | cgroup_enter_frozen(); | |
2306 | preempt_enable_no_resched(); | |
2307 | freezable_schedule(); | |
2308 | cgroup_leave_frozen(true); | |
1da177e4 LT |
2309 | |
2310 | /* | |
2311 | * We are back. Now reacquire the siglock before touching | |
2312 | * last_siginfo, so that we are sure to have synchronized with | |
2313 | * any signal-sending on another CPU that wants to examine it. | |
2314 | */ | |
2315 | spin_lock_irq(¤t->sighand->siglock); | |
57b6de08 | 2316 | exit_code = current->exit_code; |
1da177e4 | 2317 | current->last_siginfo = NULL; |
336d4b81 | 2318 | current->ptrace_message = 0; |
6487d1da | 2319 | current->exit_code = 0; |
1da177e4 | 2320 | |
544b2c91 | 2321 | /* LISTENING can be set only during STOP traps, clear it */ |
2500ad1c | 2322 | current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN); |
544b2c91 | 2323 | |
1da177e4 LT |
2324 | /* |
2325 | * Queued signals ignored us while we were stopped for tracing. | |
2326 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 2327 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 2328 | */ |
b74d0deb | 2329 | recalc_sigpending_tsk(current); |
6487d1da | 2330 | return exit_code; |
1da177e4 LT |
2331 | } |
2332 | ||
6487d1da | 2333 | static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message) |
1da177e4 | 2334 | { |
ae7795bc | 2335 | kernel_siginfo_t info; |
1da177e4 | 2336 | |
faf1f22b | 2337 | clear_siginfo(&info); |
3544d72a | 2338 | info.si_signo = signr; |
1da177e4 | 2339 | info.si_code = exit_code; |
b488893a | 2340 | info.si_pid = task_pid_vnr(current); |
078de5f7 | 2341 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
1da177e4 LT |
2342 | |
2343 | /* Let the debugger run. */ | |
57b6de08 | 2344 | return ptrace_stop(exit_code, why, message, &info); |
3544d72a TH |
2345 | } |
2346 | ||
6487d1da | 2347 | int ptrace_notify(int exit_code, unsigned long message) |
3544d72a | 2348 | { |
6487d1da EB |
2349 | int signr; |
2350 | ||
3544d72a | 2351 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); |
7f62d40d | 2352 | if (unlikely(task_work_pending(current))) |
f784e8a7 | 2353 | task_work_run(); |
3544d72a | 2354 | |
1da177e4 | 2355 | spin_lock_irq(¤t->sighand->siglock); |
6487d1da | 2356 | signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message); |
1da177e4 | 2357 | spin_unlock_irq(¤t->sighand->siglock); |
6487d1da | 2358 | return signr; |
1da177e4 LT |
2359 | } |
2360 | ||
73ddff2b TH |
2361 | /** |
2362 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals | |
2363 | * @signr: signr causing group stop if initiating | |
2364 | * | |
2365 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr | |
2366 | * and participate in it. If already set, participate in the existing | |
2367 | * group stop. If participated in a group stop (and thus slept), %true is | |
2368 | * returned with siglock released. | |
2369 | * | |
2370 | * If ptraced, this function doesn't handle stop itself. Instead, | |
2371 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock | |
2372 | * untouched. The caller must ensure that INTERRUPT trap handling takes | |
2373 | * places afterwards. | |
2374 | * | |
2375 | * CONTEXT: | |
2376 | * Must be called with @current->sighand->siglock held, which is released | |
2377 | * on %true return. | |
2378 | * | |
2379 | * RETURNS: | |
2380 | * %false if group stop is already cancelled or ptrace trap is scheduled. | |
2381 | * %true if participated in group stop. | |
1da177e4 | 2382 | */ |
73ddff2b TH |
2383 | static bool do_signal_stop(int signr) |
2384 | __releases(¤t->sighand->siglock) | |
1da177e4 LT |
2385 | { |
2386 | struct signal_struct *sig = current->signal; | |
1da177e4 | 2387 | |
a8f072c1 | 2388 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
b76808e6 | 2389 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
f558b7e4 ON |
2390 | struct task_struct *t; |
2391 | ||
a8f072c1 TH |
2392 | /* signr will be recorded in task->jobctl for retries */ |
2393 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); | |
d79fdd6d | 2394 | |
a8f072c1 | 2395 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
49697335 EB |
2396 | unlikely(sig->flags & SIGNAL_GROUP_EXIT) || |
2397 | unlikely(sig->group_exec_task)) | |
73ddff2b | 2398 | return false; |
1da177e4 | 2399 | /* |
408a37de TH |
2400 | * There is no group stop already in progress. We must |
2401 | * initiate one now. | |
2402 | * | |
2403 | * While ptraced, a task may be resumed while group stop is | |
2404 | * still in effect and then receive a stop signal and | |
2405 | * initiate another group stop. This deviates from the | |
2406 | * usual behavior as two consecutive stop signals can't | |
780006ea ON |
2407 | * cause two group stops when !ptraced. That is why we |
2408 | * also check !task_is_stopped(t) below. | |
408a37de TH |
2409 | * |
2410 | * The condition can be distinguished by testing whether | |
2411 | * SIGNAL_STOP_STOPPED is already set. Don't generate | |
2412 | * group_exit_code in such case. | |
2413 | * | |
2414 | * This is not necessary for SIGNAL_STOP_CONTINUED because | |
2415 | * an intervening stop signal is required to cause two | |
2416 | * continued events regardless of ptrace. | |
1da177e4 | 2417 | */ |
408a37de TH |
2418 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
2419 | sig->group_exit_code = signr; | |
1da177e4 | 2420 | |
7dd3db54 TH |
2421 | sig->group_stop_count = 0; |
2422 | ||
2423 | if (task_set_jobctl_pending(current, signr | gstop)) | |
2424 | sig->group_stop_count++; | |
1da177e4 | 2425 | |
8d38f203 ON |
2426 | t = current; |
2427 | while_each_thread(current, t) { | |
1da177e4 | 2428 | /* |
a122b341 ON |
2429 | * Setting state to TASK_STOPPED for a group |
2430 | * stop is always done with the siglock held, | |
2431 | * so this check has no races. | |
1da177e4 | 2432 | */ |
7dd3db54 TH |
2433 | if (!task_is_stopped(t) && |
2434 | task_set_jobctl_pending(t, signr | gstop)) { | |
ae6d2ed7 | 2435 | sig->group_stop_count++; |
fb1d910c TH |
2436 | if (likely(!(t->ptrace & PT_SEIZED))) |
2437 | signal_wake_up(t, 0); | |
2438 | else | |
2439 | ptrace_trap_notify(t); | |
a122b341 | 2440 | } |
d79fdd6d | 2441 | } |
1da177e4 | 2442 | } |
73ddff2b | 2443 | |
d21142ec | 2444 | if (likely(!current->ptrace)) { |
5224fa36 | 2445 | int notify = 0; |
1da177e4 | 2446 | |
5224fa36 TH |
2447 | /* |
2448 | * If there are no other threads in the group, or if there | |
2449 | * is a group stop in progress and we are the last to stop, | |
2450 | * report to the parent. | |
2451 | */ | |
2452 | if (task_participate_group_stop(current)) | |
2453 | notify = CLD_STOPPED; | |
2454 | ||
31cae1ea | 2455 | current->jobctl |= JOBCTL_STOPPED; |
b5bf9a90 | 2456 | set_special_state(TASK_STOPPED); |
5224fa36 TH |
2457 | spin_unlock_irq(¤t->sighand->siglock); |
2458 | ||
62bcf9d9 TH |
2459 | /* |
2460 | * Notify the parent of the group stop completion. Because | |
2461 | * we're not holding either the siglock or tasklist_lock | |
2462 | * here, ptracer may attach inbetween; however, this is for | |
2463 | * group stop and should always be delivered to the real | |
2464 | * parent of the group leader. The new ptracer will get | |
2465 | * its notification when this task transitions into | |
2466 | * TASK_TRACED. | |
2467 | */ | |
5224fa36 TH |
2468 | if (notify) { |
2469 | read_lock(&tasklist_lock); | |
62bcf9d9 | 2470 | do_notify_parent_cldstop(current, false, notify); |
5224fa36 TH |
2471 | read_unlock(&tasklist_lock); |
2472 | } | |
2473 | ||
2474 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ | |
76f969e8 | 2475 | cgroup_enter_frozen(); |
5d8f72b5 | 2476 | freezable_schedule(); |
73ddff2b | 2477 | return true; |
d79fdd6d | 2478 | } else { |
73ddff2b TH |
2479 | /* |
2480 | * While ptraced, group stop is handled by STOP trap. | |
2481 | * Schedule it and let the caller deal with it. | |
2482 | */ | |
2483 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); | |
2484 | return false; | |
ae6d2ed7 | 2485 | } |
73ddff2b | 2486 | } |
1da177e4 | 2487 | |
73ddff2b TH |
2488 | /** |
2489 | * do_jobctl_trap - take care of ptrace jobctl traps | |
2490 | * | |
3544d72a TH |
2491 | * When PT_SEIZED, it's used for both group stop and explicit |
2492 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with | |
2493 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain | |
2494 | * the stop signal; otherwise, %SIGTRAP. | |
2495 | * | |
2496 | * When !PT_SEIZED, it's used only for group stop trap with stop signal | |
2497 | * number as exit_code and no siginfo. | |
73ddff2b TH |
2498 | * |
2499 | * CONTEXT: | |
2500 | * Must be called with @current->sighand->siglock held, which may be | |
2501 | * released and re-acquired before returning with intervening sleep. | |
2502 | */ | |
2503 | static void do_jobctl_trap(void) | |
2504 | { | |
3544d72a | 2505 | struct signal_struct *signal = current->signal; |
73ddff2b | 2506 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
ae6d2ed7 | 2507 | |
3544d72a TH |
2508 | if (current->ptrace & PT_SEIZED) { |
2509 | if (!signal->group_stop_count && | |
2510 | !(signal->flags & SIGNAL_STOP_STOPPED)) | |
2511 | signr = SIGTRAP; | |
2512 | WARN_ON_ONCE(!signr); | |
2513 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), | |
336d4b81 | 2514 | CLD_STOPPED, 0); |
3544d72a TH |
2515 | } else { |
2516 | WARN_ON_ONCE(!signr); | |
57b6de08 | 2517 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); |
ae6d2ed7 | 2518 | } |
1da177e4 LT |
2519 | } |
2520 | ||
76f969e8 RG |
2521 | /** |
2522 | * do_freezer_trap - handle the freezer jobctl trap | |
2523 | * | |
2524 | * Puts the task into frozen state, if only the task is not about to quit. | |
2525 | * In this case it drops JOBCTL_TRAP_FREEZE. | |
2526 | * | |
2527 | * CONTEXT: | |
2528 | * Must be called with @current->sighand->siglock held, | |
2529 | * which is always released before returning. | |
2530 | */ | |
2531 | static void do_freezer_trap(void) | |
2532 | __releases(¤t->sighand->siglock) | |
2533 | { | |
2534 | /* | |
2535 | * If there are other trap bits pending except JOBCTL_TRAP_FREEZE, | |
2536 | * let's make another loop to give it a chance to be handled. | |
2537 | * In any case, we'll return back. | |
2538 | */ | |
2539 | if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) != | |
2540 | JOBCTL_TRAP_FREEZE) { | |
2541 | spin_unlock_irq(¤t->sighand->siglock); | |
2542 | return; | |
2543 | } | |
2544 | ||
2545 | /* | |
2546 | * Now we're sure that there is no pending fatal signal and no | |
2547 | * pending traps. Clear TIF_SIGPENDING to not get out of schedule() | |
2548 | * immediately (if there is a non-fatal signal pending), and | |
2549 | * put the task into sleep. | |
2550 | */ | |
2551 | __set_current_state(TASK_INTERRUPTIBLE); | |
2552 | clear_thread_flag(TIF_SIGPENDING); | |
2553 | spin_unlock_irq(¤t->sighand->siglock); | |
2554 | cgroup_enter_frozen(); | |
2555 | freezable_schedule(); | |
2556 | } | |
2557 | ||
5768d890 | 2558 | static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type) |
18c98b65 | 2559 | { |
8a352418 ON |
2560 | /* |
2561 | * We do not check sig_kernel_stop(signr) but set this marker | |
2562 | * unconditionally because we do not know whether debugger will | |
2563 | * change signr. This flag has no meaning unless we are going | |
2564 | * to stop after return from ptrace_stop(). In this case it will | |
2565 | * be checked in do_signal_stop(), we should only stop if it was | |
2566 | * not cleared by SIGCONT while we were sleeping. See also the | |
2567 | * comment in dequeue_signal(). | |
2568 | */ | |
2569 | current->jobctl |= JOBCTL_STOP_DEQUEUED; | |
57b6de08 | 2570 | signr = ptrace_stop(signr, CLD_TRAPPED, 0, info); |
18c98b65 RM |
2571 | |
2572 | /* We're back. Did the debugger cancel the sig? */ | |
18c98b65 RM |
2573 | if (signr == 0) |
2574 | return signr; | |
2575 | ||
5aba085e RD |
2576 | /* |
2577 | * Update the siginfo structure if the signal has | |
2578 | * changed. If the debugger wanted something | |
2579 | * specific in the siginfo structure then it should | |
2580 | * have updated *info via PTRACE_SETSIGINFO. | |
2581 | */ | |
18c98b65 | 2582 | if (signr != info->si_signo) { |
faf1f22b | 2583 | clear_siginfo(info); |
18c98b65 RM |
2584 | info->si_signo = signr; |
2585 | info->si_errno = 0; | |
2586 | info->si_code = SI_USER; | |
6b550f94 | 2587 | rcu_read_lock(); |
18c98b65 | 2588 | info->si_pid = task_pid_vnr(current->parent); |
54ba47ed EB |
2589 | info->si_uid = from_kuid_munged(current_user_ns(), |
2590 | task_uid(current->parent)); | |
6b550f94 | 2591 | rcu_read_unlock(); |
18c98b65 RM |
2592 | } |
2593 | ||
2594 | /* If the (new) signal is now blocked, requeue it. */ | |
b171f667 EB |
2595 | if (sigismember(¤t->blocked, signr) || |
2596 | fatal_signal_pending(current)) { | |
157cc181 | 2597 | send_signal_locked(signr, info, current, type); |
18c98b65 RM |
2598 | signr = 0; |
2599 | } | |
2600 | ||
2601 | return signr; | |
2602 | } | |
2603 | ||
6ac05e83 PC |
2604 | static void hide_si_addr_tag_bits(struct ksignal *ksig) |
2605 | { | |
2606 | switch (siginfo_layout(ksig->sig, ksig->info.si_code)) { | |
2607 | case SIL_FAULT: | |
9abcabe3 | 2608 | case SIL_FAULT_TRAPNO: |
6ac05e83 PC |
2609 | case SIL_FAULT_MCEERR: |
2610 | case SIL_FAULT_BNDERR: | |
2611 | case SIL_FAULT_PKUERR: | |
f4ac7302 | 2612 | case SIL_FAULT_PERF_EVENT: |
6ac05e83 PC |
2613 | ksig->info.si_addr = arch_untagged_si_addr( |
2614 | ksig->info.si_addr, ksig->sig, ksig->info.si_code); | |
2615 | break; | |
2616 | case SIL_KILL: | |
2617 | case SIL_TIMER: | |
2618 | case SIL_POLL: | |
2619 | case SIL_CHLD: | |
2620 | case SIL_RT: | |
2621 | case SIL_SYS: | |
2622 | break; | |
2623 | } | |
2624 | } | |
2625 | ||
20ab7218 | 2626 | bool get_signal(struct ksignal *ksig) |
1da177e4 | 2627 | { |
f6b76d4f ON |
2628 | struct sighand_struct *sighand = current->sighand; |
2629 | struct signal_struct *signal = current->signal; | |
2630 | int signr; | |
1da177e4 | 2631 | |
8ba62d37 | 2632 | clear_notify_signal(); |
7f62d40d | 2633 | if (unlikely(task_work_pending(current))) |
35d0b389 JA |
2634 | task_work_run(); |
2635 | ||
8ba62d37 EB |
2636 | if (!task_sigpending(current)) |
2637 | return false; | |
12db8b69 | 2638 | |
0326f5a9 | 2639 | if (unlikely(uprobe_deny_signal())) |
20ab7218 | 2640 | return false; |
0326f5a9 | 2641 | |
13b1c3d4 | 2642 | /* |
5d8f72b5 ON |
2643 | * Do this once, we can't return to user-mode if freezing() == T. |
2644 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and | |
2645 | * thus do not need another check after return. | |
13b1c3d4 | 2646 | */ |
fc558a74 RW |
2647 | try_to_freeze(); |
2648 | ||
5d8f72b5 | 2649 | relock: |
f6b76d4f | 2650 | spin_lock_irq(&sighand->siglock); |
e91b4816 | 2651 | |
021e1ae3 ON |
2652 | /* |
2653 | * Every stopped thread goes here after wakeup. Check to see if | |
2654 | * we should notify the parent, prepare_signal(SIGCONT) encodes | |
2655 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. | |
2656 | */ | |
f6b76d4f | 2657 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
c672af35 TH |
2658 | int why; |
2659 | ||
2660 | if (signal->flags & SIGNAL_CLD_CONTINUED) | |
2661 | why = CLD_CONTINUED; | |
2662 | else | |
2663 | why = CLD_STOPPED; | |
2664 | ||
f6b76d4f | 2665 | signal->flags &= ~SIGNAL_CLD_MASK; |
e4420551 | 2666 | |
ae6d2ed7 | 2667 | spin_unlock_irq(&sighand->siglock); |
fa00b80b | 2668 | |
ceb6bd67 TH |
2669 | /* |
2670 | * Notify the parent that we're continuing. This event is | |
2671 | * always per-process and doesn't make whole lot of sense | |
2672 | * for ptracers, who shouldn't consume the state via | |
2673 | * wait(2) either, but, for backward compatibility, notify | |
2674 | * the ptracer of the group leader too unless it's gonna be | |
2675 | * a duplicate. | |
2676 | */ | |
edf2ed15 | 2677 | read_lock(&tasklist_lock); |
ceb6bd67 TH |
2678 | do_notify_parent_cldstop(current, false, why); |
2679 | ||
bb3696da ON |
2680 | if (ptrace_reparented(current->group_leader)) |
2681 | do_notify_parent_cldstop(current->group_leader, | |
2682 | true, why); | |
edf2ed15 | 2683 | read_unlock(&tasklist_lock); |
ceb6bd67 | 2684 | |
e4420551 ON |
2685 | goto relock; |
2686 | } | |
2687 | ||
1da177e4 LT |
2688 | for (;;) { |
2689 | struct k_sigaction *ka; | |
5768d890 | 2690 | enum pid_type type; |
1be53963 | 2691 | |
e7f7c99b | 2692 | /* Has this task already been marked for death? */ |
49697335 EB |
2693 | if ((signal->flags & SIGNAL_GROUP_EXIT) || |
2694 | signal->group_exec_task) { | |
e7f7c99b EB |
2695 | ksig->info.si_signo = signr = SIGKILL; |
2696 | sigdelset(¤t->pending.signal, SIGKILL); | |
2697 | trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, | |
2698 | &sighand->action[SIGKILL - 1]); | |
2699 | recalc_sigpending(); | |
2700 | goto fatal; | |
2701 | } | |
1be53963 | 2702 | |
dd1d6772 TH |
2703 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
2704 | do_signal_stop(0)) | |
7bcf6a2c | 2705 | goto relock; |
1be53963 | 2706 | |
76f969e8 RG |
2707 | if (unlikely(current->jobctl & |
2708 | (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) { | |
2709 | if (current->jobctl & JOBCTL_TRAP_MASK) { | |
2710 | do_jobctl_trap(); | |
2711 | spin_unlock_irq(&sighand->siglock); | |
2712 | } else if (current->jobctl & JOBCTL_TRAP_FREEZE) | |
2713 | do_freezer_trap(); | |
2714 | ||
2715 | goto relock; | |
2716 | } | |
2717 | ||
2718 | /* | |
2719 | * If the task is leaving the frozen state, let's update | |
2720 | * cgroup counters and reset the frozen bit. | |
2721 | */ | |
2722 | if (unlikely(cgroup_task_frozen(current))) { | |
73ddff2b | 2723 | spin_unlock_irq(&sighand->siglock); |
cb2c4cd8 | 2724 | cgroup_leave_frozen(false); |
73ddff2b TH |
2725 | goto relock; |
2726 | } | |
1da177e4 | 2727 | |
7146db33 EB |
2728 | /* |
2729 | * Signals generated by the execution of an instruction | |
2730 | * need to be delivered before any other pending signals | |
2731 | * so that the instruction pointer in the signal stack | |
2732 | * frame points to the faulting instruction. | |
2733 | */ | |
5768d890 | 2734 | type = PIDTYPE_PID; |
7146db33 EB |
2735 | signr = dequeue_synchronous_signal(&ksig->info); |
2736 | if (!signr) | |
5768d890 EB |
2737 | signr = dequeue_signal(current, ¤t->blocked, |
2738 | &ksig->info, &type); | |
7bcf6a2c | 2739 | |
dd1d6772 TH |
2740 | if (!signr) |
2741 | break; /* will return 0 */ | |
7bcf6a2c | 2742 | |
00b06da2 EB |
2743 | if (unlikely(current->ptrace) && (signr != SIGKILL) && |
2744 | !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) { | |
5768d890 | 2745 | signr = ptrace_signal(signr, &ksig->info, type); |
dd1d6772 TH |
2746 | if (!signr) |
2747 | continue; | |
1da177e4 LT |
2748 | } |
2749 | ||
dd1d6772 TH |
2750 | ka = &sighand->action[signr-1]; |
2751 | ||
f9d4257e | 2752 | /* Trace actually delivered signals. */ |
828b1f65 | 2753 | trace_signal_deliver(signr, &ksig->info, ka); |
f9d4257e | 2754 | |
1da177e4 LT |
2755 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
2756 | continue; | |
2757 | if (ka->sa.sa_handler != SIG_DFL) { | |
2758 | /* Run the handler. */ | |
828b1f65 | 2759 | ksig->ka = *ka; |
1da177e4 LT |
2760 | |
2761 | if (ka->sa.sa_flags & SA_ONESHOT) | |
2762 | ka->sa.sa_handler = SIG_DFL; | |
2763 | ||
2764 | break; /* will return non-zero "signr" value */ | |
2765 | } | |
2766 | ||
2767 | /* | |
2768 | * Now we are doing the default action for this signal. | |
2769 | */ | |
2770 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
2771 | continue; | |
2772 | ||
84d73786 | 2773 | /* |
0fbc26a6 | 2774 | * Global init gets no signals it doesn't want. |
b3bfa0cb SB |
2775 | * Container-init gets no signals it doesn't want from same |
2776 | * container. | |
2777 | * | |
2778 | * Note that if global/container-init sees a sig_kernel_only() | |
2779 | * signal here, the signal must have been generated internally | |
2780 | * or must have come from an ancestor namespace. In either | |
2781 | * case, the signal cannot be dropped. | |
84d73786 | 2782 | */ |
fae5fa44 | 2783 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
b3bfa0cb | 2784 | !sig_kernel_only(signr)) |
1da177e4 LT |
2785 | continue; |
2786 | ||
2787 | if (sig_kernel_stop(signr)) { | |
2788 | /* | |
2789 | * The default action is to stop all threads in | |
2790 | * the thread group. The job control signals | |
2791 | * do nothing in an orphaned pgrp, but SIGSTOP | |
2792 | * always works. Note that siglock needs to be | |
2793 | * dropped during the call to is_orphaned_pgrp() | |
2794 | * because of lock ordering with tasklist_lock. | |
2795 | * This allows an intervening SIGCONT to be posted. | |
2796 | * We need to check for that and bail out if necessary. | |
2797 | */ | |
2798 | if (signr != SIGSTOP) { | |
f6b76d4f | 2799 | spin_unlock_irq(&sighand->siglock); |
1da177e4 LT |
2800 | |
2801 | /* signals can be posted during this window */ | |
2802 | ||
3e7cd6c4 | 2803 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
2804 | goto relock; |
2805 | ||
f6b76d4f | 2806 | spin_lock_irq(&sighand->siglock); |
1da177e4 LT |
2807 | } |
2808 | ||
828b1f65 | 2809 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
1da177e4 LT |
2810 | /* It released the siglock. */ |
2811 | goto relock; | |
2812 | } | |
2813 | ||
2814 | /* | |
2815 | * We didn't actually stop, due to a race | |
2816 | * with SIGCONT or something like that. | |
2817 | */ | |
2818 | continue; | |
2819 | } | |
2820 | ||
35634ffa | 2821 | fatal: |
f6b76d4f | 2822 | spin_unlock_irq(&sighand->siglock); |
f2b31bb5 RG |
2823 | if (unlikely(cgroup_task_frozen(current))) |
2824 | cgroup_leave_frozen(true); | |
1da177e4 LT |
2825 | |
2826 | /* | |
2827 | * Anything else is fatal, maybe with a core dump. | |
2828 | */ | |
2829 | current->flags |= PF_SIGNALED; | |
2dce81bf | 2830 | |
1da177e4 | 2831 | if (sig_kernel_coredump(signr)) { |
2dce81bf | 2832 | if (print_fatal_signals) |
828b1f65 | 2833 | print_fatal_signal(ksig->info.si_signo); |
2b5faa4c | 2834 | proc_coredump_connector(current); |
1da177e4 LT |
2835 | /* |
2836 | * If it was able to dump core, this kills all | |
2837 | * other threads in the group and synchronizes with | |
2838 | * their demise. If we lost the race with another | |
2839 | * thread getting here, it set group_exit_code | |
2840 | * first and our do_group_exit call below will use | |
2841 | * that value and ignore the one we pass it. | |
2842 | */ | |
828b1f65 | 2843 | do_coredump(&ksig->info); |
1da177e4 LT |
2844 | } |
2845 | ||
10442994 JA |
2846 | /* |
2847 | * PF_IO_WORKER threads will catch and exit on fatal signals | |
2848 | * themselves. They have cleanup that must be performed, so | |
2849 | * we cannot call do_exit() on their behalf. | |
2850 | */ | |
2851 | if (current->flags & PF_IO_WORKER) | |
2852 | goto out; | |
2853 | ||
1da177e4 LT |
2854 | /* |
2855 | * Death signals, no core dump. | |
2856 | */ | |
828b1f65 | 2857 | do_group_exit(ksig->info.si_signo); |
1da177e4 LT |
2858 | /* NOTREACHED */ |
2859 | } | |
f6b76d4f | 2860 | spin_unlock_irq(&sighand->siglock); |
10442994 | 2861 | out: |
828b1f65 | 2862 | ksig->sig = signr; |
6ac05e83 PC |
2863 | |
2864 | if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS)) | |
2865 | hide_si_addr_tag_bits(ksig); | |
2866 | ||
828b1f65 | 2867 | return ksig->sig > 0; |
1da177e4 LT |
2868 | } |
2869 | ||
5e6292c0 | 2870 | /** |
6410349e | 2871 | * signal_delivered - called after signal delivery to update blocked signals |
10b1c7ac | 2872 | * @ksig: kernel signal struct |
efee984c | 2873 | * @stepping: nonzero if debugger single-step or block-step in use |
5e6292c0 | 2874 | * |
e227867f | 2875 | * This function should be called when a signal has successfully been |
10b1c7ac | 2876 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
6410349e | 2877 | * is always blocked), and the signal itself is blocked unless %SA_NODEFER |
10b1c7ac | 2878 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
5e6292c0 | 2879 | */ |
10b1c7ac | 2880 | static void signal_delivered(struct ksignal *ksig, int stepping) |
5e6292c0 MF |
2881 | { |
2882 | sigset_t blocked; | |
2883 | ||
a610d6e6 AV |
2884 | /* A signal was successfully delivered, and the |
2885 | saved sigmask was stored on the signal frame, | |
2886 | and will be restored by sigreturn. So we can | |
2887 | simply clear the restore sigmask flag. */ | |
2888 | clear_restore_sigmask(); | |
2889 | ||
10b1c7ac RW |
2890 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
2891 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) | |
2892 | sigaddset(&blocked, ksig->sig); | |
5e6292c0 | 2893 | set_current_blocked(&blocked); |
97c885d5 AV |
2894 | if (current->sas_ss_flags & SS_AUTODISARM) |
2895 | sas_ss_reset(current); | |
c145137d | 2896 | if (stepping) |
336d4b81 | 2897 | ptrace_notify(SIGTRAP, 0); |
5e6292c0 MF |
2898 | } |
2899 | ||
2ce5da17 AV |
2900 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
2901 | { | |
2902 | if (failed) | |
cb44c9a0 | 2903 | force_sigsegv(ksig->sig); |
2ce5da17 | 2904 | else |
10b1c7ac | 2905 | signal_delivered(ksig, stepping); |
2ce5da17 AV |
2906 | } |
2907 | ||
0edceb7b ON |
2908 | /* |
2909 | * It could be that complete_signal() picked us to notify about the | |
fec9993d ON |
2910 | * group-wide signal. Other threads should be notified now to take |
2911 | * the shared signals in @which since we will not. | |
0edceb7b | 2912 | */ |
f646e227 | 2913 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
0edceb7b | 2914 | { |
f646e227 | 2915 | sigset_t retarget; |
0edceb7b ON |
2916 | struct task_struct *t; |
2917 | ||
f646e227 ON |
2918 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
2919 | if (sigisemptyset(&retarget)) | |
2920 | return; | |
2921 | ||
0edceb7b ON |
2922 | t = tsk; |
2923 | while_each_thread(tsk, t) { | |
fec9993d ON |
2924 | if (t->flags & PF_EXITING) |
2925 | continue; | |
2926 | ||
2927 | if (!has_pending_signals(&retarget, &t->blocked)) | |
2928 | continue; | |
2929 | /* Remove the signals this thread can handle. */ | |
2930 | sigandsets(&retarget, &retarget, &t->blocked); | |
2931 | ||
5c251e9d | 2932 | if (!task_sigpending(t)) |
fec9993d ON |
2933 | signal_wake_up(t, 0); |
2934 | ||
2935 | if (sigisemptyset(&retarget)) | |
2936 | break; | |
0edceb7b ON |
2937 | } |
2938 | } | |
2939 | ||
d12619b5 ON |
2940 | void exit_signals(struct task_struct *tsk) |
2941 | { | |
2942 | int group_stop = 0; | |
f646e227 | 2943 | sigset_t unblocked; |
d12619b5 | 2944 | |
77e4ef99 TH |
2945 | /* |
2946 | * @tsk is about to have PF_EXITING set - lock out users which | |
2947 | * expect stable threadgroup. | |
2948 | */ | |
780de9dd | 2949 | cgroup_threadgroup_change_begin(tsk); |
77e4ef99 | 2950 | |
49697335 | 2951 | if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) { |
5dee1707 | 2952 | tsk->flags |= PF_EXITING; |
780de9dd | 2953 | cgroup_threadgroup_change_end(tsk); |
5dee1707 | 2954 | return; |
d12619b5 ON |
2955 | } |
2956 | ||
5dee1707 | 2957 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
2958 | /* |
2959 | * From now this task is not visible for group-wide signals, | |
2960 | * see wants_signal(), do_signal_stop(). | |
2961 | */ | |
2962 | tsk->flags |= PF_EXITING; | |
77e4ef99 | 2963 | |
780de9dd | 2964 | cgroup_threadgroup_change_end(tsk); |
77e4ef99 | 2965 | |
5c251e9d | 2966 | if (!task_sigpending(tsk)) |
5dee1707 ON |
2967 | goto out; |
2968 | ||
f646e227 ON |
2969 | unblocked = tsk->blocked; |
2970 | signotset(&unblocked); | |
2971 | retarget_shared_pending(tsk, &unblocked); | |
5dee1707 | 2972 | |
a8f072c1 | 2973 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
e5c1902e | 2974 | task_participate_group_stop(tsk)) |
edf2ed15 | 2975 | group_stop = CLD_STOPPED; |
5dee1707 | 2976 | out: |
d12619b5 ON |
2977 | spin_unlock_irq(&tsk->sighand->siglock); |
2978 | ||
62bcf9d9 TH |
2979 | /* |
2980 | * If group stop has completed, deliver the notification. This | |
2981 | * should always go to the real parent of the group leader. | |
2982 | */ | |
ae6d2ed7 | 2983 | if (unlikely(group_stop)) { |
d12619b5 | 2984 | read_lock(&tasklist_lock); |
62bcf9d9 | 2985 | do_notify_parent_cldstop(tsk, false, group_stop); |
d12619b5 ON |
2986 | read_unlock(&tasklist_lock); |
2987 | } | |
2988 | } | |
2989 | ||
1da177e4 LT |
2990 | /* |
2991 | * System call entry points. | |
2992 | */ | |
2993 | ||
41c57892 RD |
2994 | /** |
2995 | * sys_restart_syscall - restart a system call | |
2996 | */ | |
754fe8d2 | 2997 | SYSCALL_DEFINE0(restart_syscall) |
1da177e4 | 2998 | { |
f56141e3 | 2999 | struct restart_block *restart = ¤t->restart_block; |
1da177e4 LT |
3000 | return restart->fn(restart); |
3001 | } | |
3002 | ||
3003 | long do_no_restart_syscall(struct restart_block *param) | |
3004 | { | |
3005 | return -EINTR; | |
3006 | } | |
3007 | ||
b182801a ON |
3008 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
3009 | { | |
5c251e9d | 3010 | if (task_sigpending(tsk) && !thread_group_empty(tsk)) { |
b182801a ON |
3011 | sigset_t newblocked; |
3012 | /* A set of now blocked but previously unblocked signals. */ | |
702a5073 | 3013 | sigandnsets(&newblocked, newset, ¤t->blocked); |
b182801a ON |
3014 | retarget_shared_pending(tsk, &newblocked); |
3015 | } | |
3016 | tsk->blocked = *newset; | |
3017 | recalc_sigpending(); | |
3018 | } | |
3019 | ||
e6fa16ab ON |
3020 | /** |
3021 | * set_current_blocked - change current->blocked mask | |
3022 | * @newset: new mask | |
3023 | * | |
3024 | * It is wrong to change ->blocked directly, this helper should be used | |
3025 | * to ensure the process can't miss a shared signal we are going to block. | |
1da177e4 | 3026 | */ |
77097ae5 AV |
3027 | void set_current_blocked(sigset_t *newset) |
3028 | { | |
77097ae5 | 3029 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
0c4a8423 | 3030 | __set_current_blocked(newset); |
77097ae5 AV |
3031 | } |
3032 | ||
3033 | void __set_current_blocked(const sigset_t *newset) | |
e6fa16ab ON |
3034 | { |
3035 | struct task_struct *tsk = current; | |
3036 | ||
c7be96af WL |
3037 | /* |
3038 | * In case the signal mask hasn't changed, there is nothing we need | |
3039 | * to do. The current->blocked shouldn't be modified by other task. | |
3040 | */ | |
3041 | if (sigequalsets(&tsk->blocked, newset)) | |
3042 | return; | |
3043 | ||
e6fa16ab | 3044 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 3045 | __set_task_blocked(tsk, newset); |
e6fa16ab ON |
3046 | spin_unlock_irq(&tsk->sighand->siglock); |
3047 | } | |
1da177e4 LT |
3048 | |
3049 | /* | |
3050 | * This is also useful for kernel threads that want to temporarily | |
3051 | * (or permanently) block certain signals. | |
3052 | * | |
3053 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
3054 | * interface happily blocks "unblockable" signals like SIGKILL | |
3055 | * and friends. | |
3056 | */ | |
3057 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
3058 | { | |
73ef4aeb ON |
3059 | struct task_struct *tsk = current; |
3060 | sigset_t newset; | |
1da177e4 | 3061 | |
73ef4aeb | 3062 | /* Lockless, only current can change ->blocked, never from irq */ |
a26fd335 | 3063 | if (oldset) |
73ef4aeb | 3064 | *oldset = tsk->blocked; |
a26fd335 | 3065 | |
1da177e4 LT |
3066 | switch (how) { |
3067 | case SIG_BLOCK: | |
73ef4aeb | 3068 | sigorsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
3069 | break; |
3070 | case SIG_UNBLOCK: | |
702a5073 | 3071 | sigandnsets(&newset, &tsk->blocked, set); |
1da177e4 LT |
3072 | break; |
3073 | case SIG_SETMASK: | |
73ef4aeb | 3074 | newset = *set; |
1da177e4 LT |
3075 | break; |
3076 | default: | |
73ef4aeb | 3077 | return -EINVAL; |
1da177e4 | 3078 | } |
a26fd335 | 3079 | |
77097ae5 | 3080 | __set_current_blocked(&newset); |
73ef4aeb | 3081 | return 0; |
1da177e4 | 3082 | } |
fb50f5a4 | 3083 | EXPORT_SYMBOL(sigprocmask); |
1da177e4 | 3084 | |
ded653cc DD |
3085 | /* |
3086 | * The api helps set app-provided sigmasks. | |
3087 | * | |
3088 | * This is useful for syscalls such as ppoll, pselect, io_pgetevents and | |
3089 | * epoll_pwait where a new sigmask is passed from userland for the syscalls. | |
b772434b ON |
3090 | * |
3091 | * Note that it does set_restore_sigmask() in advance, so it must be always | |
3092 | * paired with restore_saved_sigmask_unless() before return from syscall. | |
ded653cc | 3093 | */ |
b772434b | 3094 | int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize) |
ded653cc | 3095 | { |
b772434b | 3096 | sigset_t kmask; |
ded653cc | 3097 | |
b772434b ON |
3098 | if (!umask) |
3099 | return 0; | |
ded653cc DD |
3100 | if (sigsetsize != sizeof(sigset_t)) |
3101 | return -EINVAL; | |
b772434b | 3102 | if (copy_from_user(&kmask, umask, sizeof(sigset_t))) |
ded653cc DD |
3103 | return -EFAULT; |
3104 | ||
b772434b ON |
3105 | set_restore_sigmask(); |
3106 | current->saved_sigmask = current->blocked; | |
3107 | set_current_blocked(&kmask); | |
ded653cc DD |
3108 | |
3109 | return 0; | |
3110 | } | |
ded653cc DD |
3111 | |
3112 | #ifdef CONFIG_COMPAT | |
b772434b | 3113 | int set_compat_user_sigmask(const compat_sigset_t __user *umask, |
ded653cc DD |
3114 | size_t sigsetsize) |
3115 | { | |
b772434b | 3116 | sigset_t kmask; |
ded653cc | 3117 | |
b772434b ON |
3118 | if (!umask) |
3119 | return 0; | |
ded653cc DD |
3120 | if (sigsetsize != sizeof(compat_sigset_t)) |
3121 | return -EINVAL; | |
b772434b | 3122 | if (get_compat_sigset(&kmask, umask)) |
ded653cc DD |
3123 | return -EFAULT; |
3124 | ||
b772434b ON |
3125 | set_restore_sigmask(); |
3126 | current->saved_sigmask = current->blocked; | |
3127 | set_current_blocked(&kmask); | |
ded653cc DD |
3128 | |
3129 | return 0; | |
3130 | } | |
ded653cc DD |
3131 | #endif |
3132 | ||
41c57892 RD |
3133 | /** |
3134 | * sys_rt_sigprocmask - change the list of currently blocked signals | |
3135 | * @how: whether to add, remove, or set signals | |
ada9c933 | 3136 | * @nset: stores pending signals |
41c57892 RD |
3137 | * @oset: previous value of signal mask if non-null |
3138 | * @sigsetsize: size of sigset_t type | |
3139 | */ | |
bb7efee2 | 3140 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
17da2bd9 | 3141 | sigset_t __user *, oset, size_t, sigsetsize) |
1da177e4 | 3142 | { |
1da177e4 | 3143 | sigset_t old_set, new_set; |
bb7efee2 | 3144 | int error; |
1da177e4 LT |
3145 | |
3146 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3147 | if (sigsetsize != sizeof(sigset_t)) | |
bb7efee2 | 3148 | return -EINVAL; |
1da177e4 | 3149 | |
bb7efee2 ON |
3150 | old_set = current->blocked; |
3151 | ||
3152 | if (nset) { | |
3153 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) | |
3154 | return -EFAULT; | |
1da177e4 LT |
3155 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
3156 | ||
bb7efee2 | 3157 | error = sigprocmask(how, &new_set, NULL); |
1da177e4 | 3158 | if (error) |
bb7efee2 ON |
3159 | return error; |
3160 | } | |
1da177e4 | 3161 | |
bb7efee2 ON |
3162 | if (oset) { |
3163 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) | |
3164 | return -EFAULT; | |
1da177e4 | 3165 | } |
bb7efee2 ON |
3166 | |
3167 | return 0; | |
1da177e4 LT |
3168 | } |
3169 | ||
322a56cb | 3170 | #ifdef CONFIG_COMPAT |
322a56cb AV |
3171 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
3172 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) | |
1da177e4 | 3173 | { |
322a56cb AV |
3174 | sigset_t old_set = current->blocked; |
3175 | ||
3176 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3177 | if (sigsetsize != sizeof(sigset_t)) | |
3178 | return -EINVAL; | |
3179 | ||
3180 | if (nset) { | |
322a56cb AV |
3181 | sigset_t new_set; |
3182 | int error; | |
3968cf62 | 3183 | if (get_compat_sigset(&new_set, nset)) |
322a56cb | 3184 | return -EFAULT; |
322a56cb AV |
3185 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
3186 | ||
3187 | error = sigprocmask(how, &new_set, NULL); | |
3188 | if (error) | |
3189 | return error; | |
3190 | } | |
f454322e | 3191 | return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
322a56cb AV |
3192 | } |
3193 | #endif | |
1da177e4 | 3194 | |
b1d294c8 | 3195 | static void do_sigpending(sigset_t *set) |
1da177e4 | 3196 | { |
1da177e4 | 3197 | spin_lock_irq(¤t->sighand->siglock); |
fe9c1db2 | 3198 | sigorsets(set, ¤t->pending.signal, |
1da177e4 LT |
3199 | ¤t->signal->shared_pending.signal); |
3200 | spin_unlock_irq(¤t->sighand->siglock); | |
3201 | ||
3202 | /* Outside the lock because only this thread touches it. */ | |
fe9c1db2 | 3203 | sigandsets(set, ¤t->blocked, set); |
5aba085e | 3204 | } |
1da177e4 | 3205 | |
41c57892 RD |
3206 | /** |
3207 | * sys_rt_sigpending - examine a pending signal that has been raised | |
3208 | * while blocked | |
20f22ab4 | 3209 | * @uset: stores pending signals |
41c57892 RD |
3210 | * @sigsetsize: size of sigset_t type or larger |
3211 | */ | |
fe9c1db2 | 3212 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
1da177e4 | 3213 | { |
fe9c1db2 | 3214 | sigset_t set; |
176826af DL |
3215 | |
3216 | if (sigsetsize > sizeof(*uset)) | |
3217 | return -EINVAL; | |
3218 | ||
b1d294c8 CB |
3219 | do_sigpending(&set); |
3220 | ||
3221 | if (copy_to_user(uset, &set, sigsetsize)) | |
3222 | return -EFAULT; | |
3223 | ||
3224 | return 0; | |
fe9c1db2 AV |
3225 | } |
3226 | ||
3227 | #ifdef CONFIG_COMPAT | |
fe9c1db2 AV |
3228 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
3229 | compat_size_t, sigsetsize) | |
1da177e4 | 3230 | { |
fe9c1db2 | 3231 | sigset_t set; |
176826af DL |
3232 | |
3233 | if (sigsetsize > sizeof(*uset)) | |
3234 | return -EINVAL; | |
3235 | ||
b1d294c8 CB |
3236 | do_sigpending(&set); |
3237 | ||
3238 | return put_compat_sigset(uset, &set, sigsetsize); | |
1da177e4 | 3239 | } |
fe9c1db2 | 3240 | #endif |
1da177e4 | 3241 | |
4ce5f9c9 EB |
3242 | static const struct { |
3243 | unsigned char limit, layout; | |
3244 | } sig_sicodes[] = { | |
3245 | [SIGILL] = { NSIGILL, SIL_FAULT }, | |
3246 | [SIGFPE] = { NSIGFPE, SIL_FAULT }, | |
3247 | [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, | |
3248 | [SIGBUS] = { NSIGBUS, SIL_FAULT }, | |
3249 | [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, | |
3250 | #if defined(SIGEMT) | |
3251 | [SIGEMT] = { NSIGEMT, SIL_FAULT }, | |
3252 | #endif | |
3253 | [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, | |
3254 | [SIGPOLL] = { NSIGPOLL, SIL_POLL }, | |
3255 | [SIGSYS] = { NSIGSYS, SIL_SYS }, | |
3256 | }; | |
3257 | ||
b2a2ab52 | 3258 | static bool known_siginfo_layout(unsigned sig, int si_code) |
4ce5f9c9 EB |
3259 | { |
3260 | if (si_code == SI_KERNEL) | |
3261 | return true; | |
3262 | else if ((si_code > SI_USER)) { | |
3263 | if (sig_specific_sicodes(sig)) { | |
3264 | if (si_code <= sig_sicodes[sig].limit) | |
3265 | return true; | |
3266 | } | |
3267 | else if (si_code <= NSIGPOLL) | |
3268 | return true; | |
3269 | } | |
3270 | else if (si_code >= SI_DETHREAD) | |
3271 | return true; | |
3272 | else if (si_code == SI_ASYNCNL) | |
3273 | return true; | |
3274 | return false; | |
3275 | } | |
3276 | ||
a3670058 | 3277 | enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
cc731525 EB |
3278 | { |
3279 | enum siginfo_layout layout = SIL_KILL; | |
3280 | if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { | |
4ce5f9c9 EB |
3281 | if ((sig < ARRAY_SIZE(sig_sicodes)) && |
3282 | (si_code <= sig_sicodes[sig].limit)) { | |
3283 | layout = sig_sicodes[sig].layout; | |
31931c93 EB |
3284 | /* Handle the exceptions */ |
3285 | if ((sig == SIGBUS) && | |
3286 | (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO)) | |
3287 | layout = SIL_FAULT_MCEERR; | |
3288 | else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR)) | |
3289 | layout = SIL_FAULT_BNDERR; | |
3290 | #ifdef SEGV_PKUERR | |
3291 | else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR)) | |
3292 | layout = SIL_FAULT_PKUERR; | |
3293 | #endif | |
ed8e5080 | 3294 | else if ((sig == SIGTRAP) && (si_code == TRAP_PERF)) |
f4ac7302 | 3295 | layout = SIL_FAULT_PERF_EVENT; |
2c9f7eaf EB |
3296 | else if (IS_ENABLED(CONFIG_SPARC) && |
3297 | (sig == SIGILL) && (si_code == ILL_ILLTRP)) | |
3298 | layout = SIL_FAULT_TRAPNO; | |
7de5f68d EB |
3299 | else if (IS_ENABLED(CONFIG_ALPHA) && |
3300 | ((sig == SIGFPE) || | |
3301 | ((sig == SIGTRAP) && (si_code == TRAP_UNK)))) | |
9abcabe3 | 3302 | layout = SIL_FAULT_TRAPNO; |
31931c93 | 3303 | } |
cc731525 EB |
3304 | else if (si_code <= NSIGPOLL) |
3305 | layout = SIL_POLL; | |
3306 | } else { | |
3307 | if (si_code == SI_TIMER) | |
3308 | layout = SIL_TIMER; | |
3309 | else if (si_code == SI_SIGIO) | |
3310 | layout = SIL_POLL; | |
3311 | else if (si_code < 0) | |
3312 | layout = SIL_RT; | |
cc731525 EB |
3313 | } |
3314 | return layout; | |
3315 | } | |
3316 | ||
4ce5f9c9 EB |
3317 | static inline char __user *si_expansion(const siginfo_t __user *info) |
3318 | { | |
3319 | return ((char __user *)info) + sizeof(struct kernel_siginfo); | |
3320 | } | |
3321 | ||
ae7795bc | 3322 | int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from) |
1da177e4 | 3323 | { |
4ce5f9c9 | 3324 | char __user *expansion = si_expansion(to); |
ae7795bc | 3325 | if (copy_to_user(to, from , sizeof(struct kernel_siginfo))) |
1da177e4 | 3326 | return -EFAULT; |
4ce5f9c9 | 3327 | if (clear_user(expansion, SI_EXPANSION_SIZE)) |
1da177e4 | 3328 | return -EFAULT; |
c999b933 | 3329 | return 0; |
1da177e4 LT |
3330 | } |
3331 | ||
601d5abf EB |
3332 | static int post_copy_siginfo_from_user(kernel_siginfo_t *info, |
3333 | const siginfo_t __user *from) | |
4cd2e0e7 | 3334 | { |
601d5abf | 3335 | if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) { |
4ce5f9c9 EB |
3336 | char __user *expansion = si_expansion(from); |
3337 | char buf[SI_EXPANSION_SIZE]; | |
3338 | int i; | |
3339 | /* | |
3340 | * An unknown si_code might need more than | |
3341 | * sizeof(struct kernel_siginfo) bytes. Verify all of the | |
3342 | * extra bytes are 0. This guarantees copy_siginfo_to_user | |
3343 | * will return this data to userspace exactly. | |
3344 | */ | |
3345 | if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE)) | |
3346 | return -EFAULT; | |
3347 | for (i = 0; i < SI_EXPANSION_SIZE; i++) { | |
3348 | if (buf[i] != 0) | |
3349 | return -E2BIG; | |
3350 | } | |
3351 | } | |
4cd2e0e7 EB |
3352 | return 0; |
3353 | } | |
3354 | ||
601d5abf EB |
3355 | static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to, |
3356 | const siginfo_t __user *from) | |
3357 | { | |
3358 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) | |
3359 | return -EFAULT; | |
3360 | to->si_signo = signo; | |
3361 | return post_copy_siginfo_from_user(to, from); | |
3362 | } | |
3363 | ||
3364 | int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from) | |
3365 | { | |
3366 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) | |
3367 | return -EFAULT; | |
3368 | return post_copy_siginfo_from_user(to, from); | |
3369 | } | |
3370 | ||
212a36a1 | 3371 | #ifdef CONFIG_COMPAT |
c3b3f524 CH |
3372 | /** |
3373 | * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo | |
3374 | * @to: compat siginfo destination | |
3375 | * @from: kernel siginfo source | |
3376 | * | |
3377 | * Note: This function does not work properly for the SIGCHLD on x32, but | |
3378 | * fortunately it doesn't have to. The only valid callers for this function are | |
3379 | * copy_siginfo_to_user32, which is overriden for x32 and the coredump code. | |
3380 | * The latter does not care because SIGCHLD will never cause a coredump. | |
3381 | */ | |
3382 | void copy_siginfo_to_external32(struct compat_siginfo *to, | |
3383 | const struct kernel_siginfo *from) | |
ea64d5ac | 3384 | { |
c3b3f524 | 3385 | memset(to, 0, sizeof(*to)); |
ea64d5ac | 3386 | |
c3b3f524 CH |
3387 | to->si_signo = from->si_signo; |
3388 | to->si_errno = from->si_errno; | |
3389 | to->si_code = from->si_code; | |
ea64d5ac EB |
3390 | switch(siginfo_layout(from->si_signo, from->si_code)) { |
3391 | case SIL_KILL: | |
c3b3f524 CH |
3392 | to->si_pid = from->si_pid; |
3393 | to->si_uid = from->si_uid; | |
ea64d5ac EB |
3394 | break; |
3395 | case SIL_TIMER: | |
c3b3f524 CH |
3396 | to->si_tid = from->si_tid; |
3397 | to->si_overrun = from->si_overrun; | |
3398 | to->si_int = from->si_int; | |
ea64d5ac EB |
3399 | break; |
3400 | case SIL_POLL: | |
c3b3f524 CH |
3401 | to->si_band = from->si_band; |
3402 | to->si_fd = from->si_fd; | |
ea64d5ac EB |
3403 | break; |
3404 | case SIL_FAULT: | |
c3b3f524 | 3405 | to->si_addr = ptr_to_compat(from->si_addr); |
9abcabe3 EB |
3406 | break; |
3407 | case SIL_FAULT_TRAPNO: | |
3408 | to->si_addr = ptr_to_compat(from->si_addr); | |
c3b3f524 | 3409 | to->si_trapno = from->si_trapno; |
31931c93 EB |
3410 | break; |
3411 | case SIL_FAULT_MCEERR: | |
c3b3f524 | 3412 | to->si_addr = ptr_to_compat(from->si_addr); |
c3b3f524 | 3413 | to->si_addr_lsb = from->si_addr_lsb; |
31931c93 EB |
3414 | break; |
3415 | case SIL_FAULT_BNDERR: | |
c3b3f524 | 3416 | to->si_addr = ptr_to_compat(from->si_addr); |
c3b3f524 CH |
3417 | to->si_lower = ptr_to_compat(from->si_lower); |
3418 | to->si_upper = ptr_to_compat(from->si_upper); | |
31931c93 EB |
3419 | break; |
3420 | case SIL_FAULT_PKUERR: | |
c3b3f524 | 3421 | to->si_addr = ptr_to_compat(from->si_addr); |
c3b3f524 | 3422 | to->si_pkey = from->si_pkey; |
ea64d5ac | 3423 | break; |
f4ac7302 | 3424 | case SIL_FAULT_PERF_EVENT: |
fb6cc127 | 3425 | to->si_addr = ptr_to_compat(from->si_addr); |
0683b531 EB |
3426 | to->si_perf_data = from->si_perf_data; |
3427 | to->si_perf_type = from->si_perf_type; | |
78ed93d7 | 3428 | to->si_perf_flags = from->si_perf_flags; |
fb6cc127 | 3429 | break; |
ea64d5ac | 3430 | case SIL_CHLD: |
c3b3f524 CH |
3431 | to->si_pid = from->si_pid; |
3432 | to->si_uid = from->si_uid; | |
3433 | to->si_status = from->si_status; | |
3434 | to->si_utime = from->si_utime; | |
3435 | to->si_stime = from->si_stime; | |
ea64d5ac EB |
3436 | break; |
3437 | case SIL_RT: | |
c3b3f524 CH |
3438 | to->si_pid = from->si_pid; |
3439 | to->si_uid = from->si_uid; | |
3440 | to->si_int = from->si_int; | |
ea64d5ac EB |
3441 | break; |
3442 | case SIL_SYS: | |
c3b3f524 CH |
3443 | to->si_call_addr = ptr_to_compat(from->si_call_addr); |
3444 | to->si_syscall = from->si_syscall; | |
3445 | to->si_arch = from->si_arch; | |
ea64d5ac EB |
3446 | break; |
3447 | } | |
c3b3f524 | 3448 | } |
ea64d5ac | 3449 | |
c3b3f524 CH |
3450 | int __copy_siginfo_to_user32(struct compat_siginfo __user *to, |
3451 | const struct kernel_siginfo *from) | |
3452 | { | |
3453 | struct compat_siginfo new; | |
3454 | ||
3455 | copy_siginfo_to_external32(&new, from); | |
ea64d5ac EB |
3456 | if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) |
3457 | return -EFAULT; | |
ea64d5ac EB |
3458 | return 0; |
3459 | } | |
3460 | ||
601d5abf EB |
3461 | static int post_copy_siginfo_from_user32(kernel_siginfo_t *to, |
3462 | const struct compat_siginfo *from) | |
212a36a1 | 3463 | { |
212a36a1 | 3464 | clear_siginfo(to); |
601d5abf EB |
3465 | to->si_signo = from->si_signo; |
3466 | to->si_errno = from->si_errno; | |
3467 | to->si_code = from->si_code; | |
3468 | switch(siginfo_layout(from->si_signo, from->si_code)) { | |
212a36a1 | 3469 | case SIL_KILL: |
601d5abf EB |
3470 | to->si_pid = from->si_pid; |
3471 | to->si_uid = from->si_uid; | |
212a36a1 EB |
3472 | break; |
3473 | case SIL_TIMER: | |
601d5abf EB |
3474 | to->si_tid = from->si_tid; |
3475 | to->si_overrun = from->si_overrun; | |
3476 | to->si_int = from->si_int; | |
212a36a1 EB |
3477 | break; |
3478 | case SIL_POLL: | |
601d5abf EB |
3479 | to->si_band = from->si_band; |
3480 | to->si_fd = from->si_fd; | |
212a36a1 EB |
3481 | break; |
3482 | case SIL_FAULT: | |
601d5abf | 3483 | to->si_addr = compat_ptr(from->si_addr); |
9abcabe3 EB |
3484 | break; |
3485 | case SIL_FAULT_TRAPNO: | |
3486 | to->si_addr = compat_ptr(from->si_addr); | |
601d5abf | 3487 | to->si_trapno = from->si_trapno; |
31931c93 EB |
3488 | break; |
3489 | case SIL_FAULT_MCEERR: | |
601d5abf | 3490 | to->si_addr = compat_ptr(from->si_addr); |
601d5abf | 3491 | to->si_addr_lsb = from->si_addr_lsb; |
31931c93 EB |
3492 | break; |
3493 | case SIL_FAULT_BNDERR: | |
601d5abf | 3494 | to->si_addr = compat_ptr(from->si_addr); |
601d5abf EB |
3495 | to->si_lower = compat_ptr(from->si_lower); |
3496 | to->si_upper = compat_ptr(from->si_upper); | |
31931c93 EB |
3497 | break; |
3498 | case SIL_FAULT_PKUERR: | |
601d5abf | 3499 | to->si_addr = compat_ptr(from->si_addr); |
601d5abf | 3500 | to->si_pkey = from->si_pkey; |
212a36a1 | 3501 | break; |
f4ac7302 | 3502 | case SIL_FAULT_PERF_EVENT: |
fb6cc127 | 3503 | to->si_addr = compat_ptr(from->si_addr); |
0683b531 EB |
3504 | to->si_perf_data = from->si_perf_data; |
3505 | to->si_perf_type = from->si_perf_type; | |
78ed93d7 | 3506 | to->si_perf_flags = from->si_perf_flags; |
fb6cc127 | 3507 | break; |
212a36a1 | 3508 | case SIL_CHLD: |
601d5abf EB |
3509 | to->si_pid = from->si_pid; |
3510 | to->si_uid = from->si_uid; | |
3511 | to->si_status = from->si_status; | |
212a36a1 EB |
3512 | #ifdef CONFIG_X86_X32_ABI |
3513 | if (in_x32_syscall()) { | |
601d5abf EB |
3514 | to->si_utime = from->_sifields._sigchld_x32._utime; |
3515 | to->si_stime = from->_sifields._sigchld_x32._stime; | |
212a36a1 EB |
3516 | } else |
3517 | #endif | |
3518 | { | |
601d5abf EB |
3519 | to->si_utime = from->si_utime; |
3520 | to->si_stime = from->si_stime; | |
212a36a1 EB |
3521 | } |
3522 | break; | |
3523 | case SIL_RT: | |
601d5abf EB |
3524 | to->si_pid = from->si_pid; |
3525 | to->si_uid = from->si_uid; | |
3526 | to->si_int = from->si_int; | |
212a36a1 EB |
3527 | break; |
3528 | case SIL_SYS: | |
601d5abf EB |
3529 | to->si_call_addr = compat_ptr(from->si_call_addr); |
3530 | to->si_syscall = from->si_syscall; | |
3531 | to->si_arch = from->si_arch; | |
212a36a1 EB |
3532 | break; |
3533 | } | |
3534 | return 0; | |
3535 | } | |
601d5abf EB |
3536 | |
3537 | static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to, | |
3538 | const struct compat_siginfo __user *ufrom) | |
3539 | { | |
3540 | struct compat_siginfo from; | |
3541 | ||
3542 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) | |
3543 | return -EFAULT; | |
3544 | ||
3545 | from.si_signo = signo; | |
3546 | return post_copy_siginfo_from_user32(to, &from); | |
3547 | } | |
3548 | ||
3549 | int copy_siginfo_from_user32(struct kernel_siginfo *to, | |
3550 | const struct compat_siginfo __user *ufrom) | |
3551 | { | |
3552 | struct compat_siginfo from; | |
3553 | ||
3554 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) | |
3555 | return -EFAULT; | |
3556 | ||
3557 | return post_copy_siginfo_from_user32(to, &from); | |
3558 | } | |
212a36a1 EB |
3559 | #endif /* CONFIG_COMPAT */ |
3560 | ||
943df148 ON |
3561 | /** |
3562 | * do_sigtimedwait - wait for queued signals specified in @which | |
3563 | * @which: queued signals to wait for | |
3564 | * @info: if non-null, the signal's siginfo is returned here | |
3565 | * @ts: upper bound on process time suspension | |
3566 | */ | |
ae7795bc | 3567 | static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info, |
49c39f84 | 3568 | const struct timespec64 *ts) |
943df148 | 3569 | { |
2456e855 | 3570 | ktime_t *to = NULL, timeout = KTIME_MAX; |
943df148 | 3571 | struct task_struct *tsk = current; |
943df148 | 3572 | sigset_t mask = *which; |
5768d890 | 3573 | enum pid_type type; |
2b1ecc3d | 3574 | int sig, ret = 0; |
943df148 ON |
3575 | |
3576 | if (ts) { | |
49c39f84 | 3577 | if (!timespec64_valid(ts)) |
943df148 | 3578 | return -EINVAL; |
49c39f84 | 3579 | timeout = timespec64_to_ktime(*ts); |
2b1ecc3d | 3580 | to = &timeout; |
943df148 ON |
3581 | } |
3582 | ||
3583 | /* | |
3584 | * Invert the set of allowed signals to get those we want to block. | |
3585 | */ | |
3586 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
3587 | signotset(&mask); | |
3588 | ||
3589 | spin_lock_irq(&tsk->sighand->siglock); | |
5768d890 | 3590 | sig = dequeue_signal(tsk, &mask, info, &type); |
2456e855 | 3591 | if (!sig && timeout) { |
943df148 ON |
3592 | /* |
3593 | * None ready, temporarily unblock those we're interested | |
3594 | * while we are sleeping in so that we'll be awakened when | |
b182801a ON |
3595 | * they arrive. Unblocking is always fine, we can avoid |
3596 | * set_current_blocked(). | |
943df148 ON |
3597 | */ |
3598 | tsk->real_blocked = tsk->blocked; | |
3599 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); | |
3600 | recalc_sigpending(); | |
3601 | spin_unlock_irq(&tsk->sighand->siglock); | |
3602 | ||
2b1ecc3d TG |
3603 | __set_current_state(TASK_INTERRUPTIBLE); |
3604 | ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns, | |
3605 | HRTIMER_MODE_REL); | |
943df148 | 3606 | spin_lock_irq(&tsk->sighand->siglock); |
b182801a | 3607 | __set_task_blocked(tsk, &tsk->real_blocked); |
6114041a | 3608 | sigemptyset(&tsk->real_blocked); |
5768d890 | 3609 | sig = dequeue_signal(tsk, &mask, info, &type); |
943df148 ON |
3610 | } |
3611 | spin_unlock_irq(&tsk->sighand->siglock); | |
3612 | ||
3613 | if (sig) | |
3614 | return sig; | |
2b1ecc3d | 3615 | return ret ? -EINTR : -EAGAIN; |
943df148 ON |
3616 | } |
3617 | ||
41c57892 RD |
3618 | /** |
3619 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified | |
3620 | * in @uthese | |
3621 | * @uthese: queued signals to wait for | |
3622 | * @uinfo: if non-null, the signal's siginfo is returned here | |
3623 | * @uts: upper bound on process time suspension | |
3624 | * @sigsetsize: size of sigset_t type | |
3625 | */ | |
17da2bd9 | 3626 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
49c39f84 AB |
3627 | siginfo_t __user *, uinfo, |
3628 | const struct __kernel_timespec __user *, uts, | |
17da2bd9 | 3629 | size_t, sigsetsize) |
1da177e4 | 3630 | { |
1da177e4 | 3631 | sigset_t these; |
49c39f84 | 3632 | struct timespec64 ts; |
ae7795bc | 3633 | kernel_siginfo_t info; |
943df148 | 3634 | int ret; |
1da177e4 LT |
3635 | |
3636 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
3637 | if (sigsetsize != sizeof(sigset_t)) | |
3638 | return -EINVAL; | |
3639 | ||
3640 | if (copy_from_user(&these, uthese, sizeof(these))) | |
3641 | return -EFAULT; | |
5aba085e | 3642 | |
1da177e4 | 3643 | if (uts) { |
49c39f84 | 3644 | if (get_timespec64(&ts, uts)) |
1da177e4 | 3645 | return -EFAULT; |
1da177e4 LT |
3646 | } |
3647 | ||
943df148 | 3648 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
1da177e4 | 3649 | |
943df148 ON |
3650 | if (ret > 0 && uinfo) { |
3651 | if (copy_siginfo_to_user(uinfo, &info)) | |
3652 | ret = -EFAULT; | |
1da177e4 LT |
3653 | } |
3654 | ||
3655 | return ret; | |
3656 | } | |
3657 | ||
df8522a3 AB |
3658 | #ifdef CONFIG_COMPAT_32BIT_TIME |
3659 | SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese, | |
3660 | siginfo_t __user *, uinfo, | |
3661 | const struct old_timespec32 __user *, uts, | |
3662 | size_t, sigsetsize) | |
3663 | { | |
3664 | sigset_t these; | |
3665 | struct timespec64 ts; | |
3666 | kernel_siginfo_t info; | |
3667 | int ret; | |
3668 | ||
3669 | if (sigsetsize != sizeof(sigset_t)) | |
3670 | return -EINVAL; | |
3671 | ||
3672 | if (copy_from_user(&these, uthese, sizeof(these))) | |
3673 | return -EFAULT; | |
3674 | ||
3675 | if (uts) { | |
3676 | if (get_old_timespec32(&ts, uts)) | |
3677 | return -EFAULT; | |
3678 | } | |
3679 | ||
3680 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); | |
3681 | ||
3682 | if (ret > 0 && uinfo) { | |
3683 | if (copy_siginfo_to_user(uinfo, &info)) | |
3684 | ret = -EFAULT; | |
3685 | } | |
3686 | ||
3687 | return ret; | |
3688 | } | |
3689 | #endif | |
3690 | ||
1b3c872c | 3691 | #ifdef CONFIG_COMPAT |
2367c4b5 AB |
3692 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese, |
3693 | struct compat_siginfo __user *, uinfo, | |
3694 | struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize) | |
3695 | { | |
3696 | sigset_t s; | |
3697 | struct timespec64 t; | |
3698 | kernel_siginfo_t info; | |
3699 | long ret; | |
3700 | ||
3701 | if (sigsetsize != sizeof(sigset_t)) | |
3702 | return -EINVAL; | |
3703 | ||
3704 | if (get_compat_sigset(&s, uthese)) | |
3705 | return -EFAULT; | |
3706 | ||
3707 | if (uts) { | |
3708 | if (get_timespec64(&t, uts)) | |
3709 | return -EFAULT; | |
3710 | } | |
3711 | ||
3712 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
3713 | ||
3714 | if (ret > 0 && uinfo) { | |
3715 | if (copy_siginfo_to_user32(uinfo, &info)) | |
3716 | ret = -EFAULT; | |
3717 | } | |
3718 | ||
3719 | return ret; | |
3720 | } | |
3721 | ||
3722 | #ifdef CONFIG_COMPAT_32BIT_TIME | |
8dabe724 | 3723 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese, |
1b3c872c | 3724 | struct compat_siginfo __user *, uinfo, |
9afc5eee | 3725 | struct old_timespec32 __user *, uts, compat_size_t, sigsetsize) |
1b3c872c | 3726 | { |
1b3c872c | 3727 | sigset_t s; |
49c39f84 | 3728 | struct timespec64 t; |
ae7795bc | 3729 | kernel_siginfo_t info; |
1b3c872c AV |
3730 | long ret; |
3731 | ||
3732 | if (sigsetsize != sizeof(sigset_t)) | |
3733 | return -EINVAL; | |
3734 | ||
3968cf62 | 3735 | if (get_compat_sigset(&s, uthese)) |
1b3c872c | 3736 | return -EFAULT; |
1b3c872c AV |
3737 | |
3738 | if (uts) { | |
49c39f84 | 3739 | if (get_old_timespec32(&t, uts)) |
1b3c872c AV |
3740 | return -EFAULT; |
3741 | } | |
3742 | ||
3743 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); | |
3744 | ||
3745 | if (ret > 0 && uinfo) { | |
3746 | if (copy_siginfo_to_user32(uinfo, &info)) | |
3747 | ret = -EFAULT; | |
3748 | } | |
3749 | ||
3750 | return ret; | |
3751 | } | |
3752 | #endif | |
2367c4b5 | 3753 | #endif |
1b3c872c | 3754 | |
3eb39f47 CB |
3755 | static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info) |
3756 | { | |
3757 | clear_siginfo(info); | |
3758 | info->si_signo = sig; | |
3759 | info->si_errno = 0; | |
3760 | info->si_code = SI_USER; | |
3761 | info->si_pid = task_tgid_vnr(current); | |
3762 | info->si_uid = from_kuid_munged(current_user_ns(), current_uid()); | |
3763 | } | |
3764 | ||
41c57892 RD |
3765 | /** |
3766 | * sys_kill - send a signal to a process | |
3767 | * @pid: the PID of the process | |
3768 | * @sig: signal to be sent | |
3769 | */ | |
17da2bd9 | 3770 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
1da177e4 | 3771 | { |
ae7795bc | 3772 | struct kernel_siginfo info; |
1da177e4 | 3773 | |
3eb39f47 | 3774 | prepare_kill_siginfo(sig, &info); |
1da177e4 LT |
3775 | |
3776 | return kill_something_info(sig, &info, pid); | |
3777 | } | |
3778 | ||
3eb39f47 CB |
3779 | /* |
3780 | * Verify that the signaler and signalee either are in the same pid namespace | |
3781 | * or that the signaler's pid namespace is an ancestor of the signalee's pid | |
3782 | * namespace. | |
3783 | */ | |
3784 | static bool access_pidfd_pidns(struct pid *pid) | |
3785 | { | |
3786 | struct pid_namespace *active = task_active_pid_ns(current); | |
3787 | struct pid_namespace *p = ns_of_pid(pid); | |
3788 | ||
3789 | for (;;) { | |
3790 | if (!p) | |
3791 | return false; | |
3792 | if (p == active) | |
3793 | break; | |
3794 | p = p->parent; | |
3795 | } | |
3796 | ||
3797 | return true; | |
3798 | } | |
3799 | ||
adc5d875 JH |
3800 | static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, |
3801 | siginfo_t __user *info) | |
3eb39f47 CB |
3802 | { |
3803 | #ifdef CONFIG_COMPAT | |
3804 | /* | |
3805 | * Avoid hooking up compat syscalls and instead handle necessary | |
3806 | * conversions here. Note, this is a stop-gap measure and should not be | |
3807 | * considered a generic solution. | |
3808 | */ | |
3809 | if (in_compat_syscall()) | |
3810 | return copy_siginfo_from_user32( | |
3811 | kinfo, (struct compat_siginfo __user *)info); | |
3812 | #endif | |
3813 | return copy_siginfo_from_user(kinfo, info); | |
3814 | } | |
3815 | ||
2151ad1b CB |
3816 | static struct pid *pidfd_to_pid(const struct file *file) |
3817 | { | |
3695eae5 CB |
3818 | struct pid *pid; |
3819 | ||
3820 | pid = pidfd_pid(file); | |
3821 | if (!IS_ERR(pid)) | |
3822 | return pid; | |
2151ad1b CB |
3823 | |
3824 | return tgid_pidfd_to_pid(file); | |
3825 | } | |
3826 | ||
3eb39f47 | 3827 | /** |
c732327f CB |
3828 | * sys_pidfd_send_signal - Signal a process through a pidfd |
3829 | * @pidfd: file descriptor of the process | |
3830 | * @sig: signal to send | |
3831 | * @info: signal info | |
3832 | * @flags: future flags | |
3eb39f47 CB |
3833 | * |
3834 | * The syscall currently only signals via PIDTYPE_PID which covers | |
3835 | * kill(<positive-pid>, <signal>. It does not signal threads or process | |
3836 | * groups. | |
3837 | * In order to extend the syscall to threads and process groups the @flags | |
3838 | * argument should be used. In essence, the @flags argument will determine | |
3839 | * what is signaled and not the file descriptor itself. Put in other words, | |
3840 | * grouping is a property of the flags argument not a property of the file | |
3841 | * descriptor. | |
3842 | * | |
3843 | * Return: 0 on success, negative errno on failure | |
3844 | */ | |
3845 | SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, | |
3846 | siginfo_t __user *, info, unsigned int, flags) | |
3847 | { | |
3848 | int ret; | |
3849 | struct fd f; | |
3850 | struct pid *pid; | |
3851 | kernel_siginfo_t kinfo; | |
3852 | ||
3853 | /* Enforce flags be set to 0 until we add an extension. */ | |
3854 | if (flags) | |
3855 | return -EINVAL; | |
3856 | ||
738a7832 | 3857 | f = fdget(pidfd); |
3eb39f47 CB |
3858 | if (!f.file) |
3859 | return -EBADF; | |
3860 | ||
3861 | /* Is this a pidfd? */ | |
2151ad1b | 3862 | pid = pidfd_to_pid(f.file); |
3eb39f47 CB |
3863 | if (IS_ERR(pid)) { |
3864 | ret = PTR_ERR(pid); | |
3865 | goto err; | |
3866 | } | |
3867 | ||
3868 | ret = -EINVAL; | |
3869 | if (!access_pidfd_pidns(pid)) | |
3870 | goto err; | |
3871 | ||
3872 | if (info) { | |
3873 | ret = copy_siginfo_from_user_any(&kinfo, info); | |
3874 | if (unlikely(ret)) | |
3875 | goto err; | |
3876 | ||
3877 | ret = -EINVAL; | |
3878 | if (unlikely(sig != kinfo.si_signo)) | |
3879 | goto err; | |
3880 | ||
556a888a JH |
3881 | /* Only allow sending arbitrary signals to yourself. */ |
3882 | ret = -EPERM; | |
3eb39f47 | 3883 | if ((task_pid(current) != pid) && |
556a888a JH |
3884 | (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) |
3885 | goto err; | |
3eb39f47 CB |
3886 | } else { |
3887 | prepare_kill_siginfo(sig, &kinfo); | |
3888 | } | |
3889 | ||
3890 | ret = kill_pid_info(sig, &kinfo, pid); | |
3891 | ||
3892 | err: | |
3893 | fdput(f); | |
3894 | return ret; | |
3895 | } | |
3eb39f47 | 3896 | |
30b4ae8a | 3897 | static int |
ae7795bc | 3898 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info) |
1da177e4 | 3899 | { |
1da177e4 | 3900 | struct task_struct *p; |
30b4ae8a | 3901 | int error = -ESRCH; |
1da177e4 | 3902 | |
3547ff3a | 3903 | rcu_read_lock(); |
228ebcbe | 3904 | p = find_task_by_vpid(pid); |
b488893a | 3905 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
30b4ae8a | 3906 | error = check_kill_permission(sig, info, p); |
1da177e4 LT |
3907 | /* |
3908 | * The null signal is a permissions and process existence | |
3909 | * probe. No signal is actually delivered. | |
3910 | */ | |
4a30debf | 3911 | if (!error && sig) { |
40b3b025 | 3912 | error = do_send_sig_info(sig, info, p, PIDTYPE_PID); |
4a30debf ON |
3913 | /* |
3914 | * If lock_task_sighand() failed we pretend the task | |
3915 | * dies after receiving the signal. The window is tiny, | |
3916 | * and the signal is private anyway. | |
3917 | */ | |
3918 | if (unlikely(error == -ESRCH)) | |
3919 | error = 0; | |
1da177e4 LT |
3920 | } |
3921 | } | |
3547ff3a | 3922 | rcu_read_unlock(); |
6dd69f10 | 3923 | |
1da177e4 LT |
3924 | return error; |
3925 | } | |
3926 | ||
30b4ae8a TG |
3927 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
3928 | { | |
ae7795bc | 3929 | struct kernel_siginfo info; |
30b4ae8a | 3930 | |
5f74972c | 3931 | clear_siginfo(&info); |
30b4ae8a TG |
3932 | info.si_signo = sig; |
3933 | info.si_errno = 0; | |
3934 | info.si_code = SI_TKILL; | |
3935 | info.si_pid = task_tgid_vnr(current); | |
078de5f7 | 3936 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
30b4ae8a TG |
3937 | |
3938 | return do_send_specific(tgid, pid, sig, &info); | |
3939 | } | |
3940 | ||
6dd69f10 VL |
3941 | /** |
3942 | * sys_tgkill - send signal to one specific thread | |
3943 | * @tgid: the thread group ID of the thread | |
3944 | * @pid: the PID of the thread | |
3945 | * @sig: signal to be sent | |
3946 | * | |
72fd4a35 | 3947 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
3948 | * exists but it's not belonging to the target process anymore. This |
3949 | * method solves the problem of threads exiting and PIDs getting reused. | |
3950 | */ | |
a5f8fa9e | 3951 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
6dd69f10 VL |
3952 | { |
3953 | /* This is only valid for single tasks */ | |
3954 | if (pid <= 0 || tgid <= 0) | |
3955 | return -EINVAL; | |
3956 | ||
3957 | return do_tkill(tgid, pid, sig); | |
3958 | } | |
3959 | ||
41c57892 RD |
3960 | /** |
3961 | * sys_tkill - send signal to one specific task | |
3962 | * @pid: the PID of the task | |
3963 | * @sig: signal to be sent | |
3964 | * | |
1da177e4 LT |
3965 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
3966 | */ | |
a5f8fa9e | 3967 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
1da177e4 | 3968 | { |
1da177e4 LT |
3969 | /* This is only valid for single tasks */ |
3970 | if (pid <= 0) | |
3971 | return -EINVAL; | |
3972 | ||
6dd69f10 | 3973 | return do_tkill(0, pid, sig); |
1da177e4 LT |
3974 | } |
3975 | ||
ae7795bc | 3976 | static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info) |
75907d4d AV |
3977 | { |
3978 | /* Not even root can pretend to send signals from the kernel. | |
3979 | * Nor can they impersonate a kill()/tgkill(), which adds source info. | |
3980 | */ | |
66dd34ad | 3981 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
69828dce | 3982 | (task_pid_vnr(current) != pid)) |
75907d4d | 3983 | return -EPERM; |
69828dce | 3984 | |
75907d4d AV |
3985 | /* POSIX.1b doesn't mention process groups. */ |
3986 | return kill_proc_info(sig, info, pid); | |
3987 | } | |
3988 | ||
41c57892 RD |
3989 | /** |
3990 | * sys_rt_sigqueueinfo - send signal information to a signal | |
3991 | * @pid: the PID of the thread | |
3992 | * @sig: signal to be sent | |
3993 | * @uinfo: signal info to be sent | |
3994 | */ | |
a5f8fa9e HC |
3995 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
3996 | siginfo_t __user *, uinfo) | |
1da177e4 | 3997 | { |
ae7795bc | 3998 | kernel_siginfo_t info; |
601d5abf | 3999 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
4cd2e0e7 EB |
4000 | if (unlikely(ret)) |
4001 | return ret; | |
75907d4d AV |
4002 | return do_rt_sigqueueinfo(pid, sig, &info); |
4003 | } | |
1da177e4 | 4004 | |
75907d4d | 4005 | #ifdef CONFIG_COMPAT |
75907d4d AV |
4006 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
4007 | compat_pid_t, pid, | |
4008 | int, sig, | |
4009 | struct compat_siginfo __user *, uinfo) | |
4010 | { | |
ae7795bc | 4011 | kernel_siginfo_t info; |
601d5abf | 4012 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
75907d4d AV |
4013 | if (unlikely(ret)) |
4014 | return ret; | |
4015 | return do_rt_sigqueueinfo(pid, sig, &info); | |
1da177e4 | 4016 | } |
75907d4d | 4017 | #endif |
1da177e4 | 4018 | |
ae7795bc | 4019 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info) |
62ab4505 TG |
4020 | { |
4021 | /* This is only valid for single tasks */ | |
4022 | if (pid <= 0 || tgid <= 0) | |
4023 | return -EINVAL; | |
4024 | ||
4025 | /* Not even root can pretend to send signals from the kernel. | |
da48524e JT |
4026 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
4027 | */ | |
69828dce VD |
4028 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
4029 | (task_pid_vnr(current) != pid)) | |
62ab4505 | 4030 | return -EPERM; |
69828dce | 4031 | |
62ab4505 TG |
4032 | return do_send_specific(tgid, pid, sig, info); |
4033 | } | |
4034 | ||
4035 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, | |
4036 | siginfo_t __user *, uinfo) | |
4037 | { | |
ae7795bc | 4038 | kernel_siginfo_t info; |
601d5abf | 4039 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
4cd2e0e7 EB |
4040 | if (unlikely(ret)) |
4041 | return ret; | |
62ab4505 TG |
4042 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
4043 | } | |
4044 | ||
9aae8fc0 AV |
4045 | #ifdef CONFIG_COMPAT |
4046 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, | |
4047 | compat_pid_t, tgid, | |
4048 | compat_pid_t, pid, | |
4049 | int, sig, | |
4050 | struct compat_siginfo __user *, uinfo) | |
4051 | { | |
ae7795bc | 4052 | kernel_siginfo_t info; |
601d5abf | 4053 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
4cd2e0e7 EB |
4054 | if (unlikely(ret)) |
4055 | return ret; | |
9aae8fc0 AV |
4056 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
4057 | } | |
4058 | #endif | |
4059 | ||
0341729b | 4060 | /* |
b4e74264 | 4061 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
0341729b | 4062 | */ |
b4e74264 | 4063 | void kernel_sigaction(int sig, __sighandler_t action) |
0341729b | 4064 | { |
ec5955b8 | 4065 | spin_lock_irq(¤t->sighand->siglock); |
b4e74264 ON |
4066 | current->sighand->action[sig - 1].sa.sa_handler = action; |
4067 | if (action == SIG_IGN) { | |
4068 | sigset_t mask; | |
0341729b | 4069 | |
b4e74264 ON |
4070 | sigemptyset(&mask); |
4071 | sigaddset(&mask, sig); | |
580d34e4 | 4072 | |
b4e74264 ON |
4073 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
4074 | flush_sigqueue_mask(&mask, ¤t->pending); | |
4075 | recalc_sigpending(); | |
4076 | } | |
0341729b ON |
4077 | spin_unlock_irq(¤t->sighand->siglock); |
4078 | } | |
b4e74264 | 4079 | EXPORT_SYMBOL(kernel_sigaction); |
0341729b | 4080 | |
68463510 DS |
4081 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
4082 | struct k_sigaction *oact) | |
4083 | { | |
4084 | } | |
4085 | ||
88531f72 | 4086 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 | 4087 | { |
afe2b038 | 4088 | struct task_struct *p = current, *t; |
1da177e4 | 4089 | struct k_sigaction *k; |
71fabd5e | 4090 | sigset_t mask; |
1da177e4 | 4091 | |
7ed20e1a | 4092 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
4093 | return -EINVAL; |
4094 | ||
afe2b038 | 4095 | k = &p->sighand->action[sig-1]; |
1da177e4 | 4096 | |
afe2b038 | 4097 | spin_lock_irq(&p->sighand->siglock); |
00b06da2 EB |
4098 | if (k->sa.sa_flags & SA_IMMUTABLE) { |
4099 | spin_unlock_irq(&p->sighand->siglock); | |
4100 | return -EINVAL; | |
4101 | } | |
1da177e4 LT |
4102 | if (oact) |
4103 | *oact = *k; | |
4104 | ||
a54f0dfd PC |
4105 | /* |
4106 | * Make sure that we never accidentally claim to support SA_UNSUPPORTED, | |
4107 | * e.g. by having an architecture use the bit in their uapi. | |
4108 | */ | |
4109 | BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED); | |
4110 | ||
23acdc76 PC |
4111 | /* |
4112 | * Clear unknown flag bits in order to allow userspace to detect missing | |
4113 | * support for flag bits and to allow the kernel to use non-uapi bits | |
4114 | * internally. | |
4115 | */ | |
4116 | if (act) | |
4117 | act->sa.sa_flags &= UAPI_SA_FLAGS; | |
4118 | if (oact) | |
4119 | oact->sa.sa_flags &= UAPI_SA_FLAGS; | |
4120 | ||
68463510 DS |
4121 | sigaction_compat_abi(act, oact); |
4122 | ||
1da177e4 | 4123 | if (act) { |
9ac95f2f ON |
4124 | sigdelsetmask(&act->sa.sa_mask, |
4125 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 4126 | *k = *act; |
1da177e4 LT |
4127 | /* |
4128 | * POSIX 3.3.1.3: | |
4129 | * "Setting a signal action to SIG_IGN for a signal that is | |
4130 | * pending shall cause the pending signal to be discarded, | |
4131 | * whether or not it is blocked." | |
4132 | * | |
4133 | * "Setting a signal action to SIG_DFL for a signal that is | |
4134 | * pending and whose default action is to ignore the signal | |
4135 | * (for example, SIGCHLD), shall cause the pending signal to | |
4136 | * be discarded, whether or not it is blocked" | |
4137 | */ | |
afe2b038 | 4138 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
71fabd5e GA |
4139 | sigemptyset(&mask); |
4140 | sigaddset(&mask, sig); | |
afe2b038 ON |
4141 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
4142 | for_each_thread(p, t) | |
c09c1441 | 4143 | flush_sigqueue_mask(&mask, &t->pending); |
1da177e4 | 4144 | } |
1da177e4 LT |
4145 | } |
4146 | ||
afe2b038 | 4147 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
4148 | return 0; |
4149 | } | |
4150 | ||
1bdda24c TG |
4151 | #ifdef CONFIG_DYNAMIC_SIGFRAME |
4152 | static inline void sigaltstack_lock(void) | |
4153 | __acquires(¤t->sighand->siglock) | |
4154 | { | |
4155 | spin_lock_irq(¤t->sighand->siglock); | |
4156 | } | |
4157 | ||
4158 | static inline void sigaltstack_unlock(void) | |
4159 | __releases(¤t->sighand->siglock) | |
4160 | { | |
4161 | spin_unlock_irq(¤t->sighand->siglock); | |
4162 | } | |
4163 | #else | |
4164 | static inline void sigaltstack_lock(void) { } | |
4165 | static inline void sigaltstack_unlock(void) { } | |
4166 | #endif | |
4167 | ||
c09c1441 | 4168 | static int |
22839869 WD |
4169 | do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
4170 | size_t min_ss_size) | |
1da177e4 | 4171 | { |
bcfe8ad8 | 4172 | struct task_struct *t = current; |
1bdda24c | 4173 | int ret = 0; |
1da177e4 | 4174 | |
bcfe8ad8 AV |
4175 | if (oss) { |
4176 | memset(oss, 0, sizeof(stack_t)); | |
4177 | oss->ss_sp = (void __user *) t->sas_ss_sp; | |
4178 | oss->ss_size = t->sas_ss_size; | |
4179 | oss->ss_flags = sas_ss_flags(sp) | | |
4180 | (current->sas_ss_flags & SS_FLAG_BITS); | |
4181 | } | |
1da177e4 | 4182 | |
bcfe8ad8 AV |
4183 | if (ss) { |
4184 | void __user *ss_sp = ss->ss_sp; | |
4185 | size_t ss_size = ss->ss_size; | |
4186 | unsigned ss_flags = ss->ss_flags; | |
407bc16a | 4187 | int ss_mode; |
1da177e4 | 4188 | |
bcfe8ad8 AV |
4189 | if (unlikely(on_sig_stack(sp))) |
4190 | return -EPERM; | |
1da177e4 | 4191 | |
407bc16a | 4192 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
bcfe8ad8 AV |
4193 | if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
4194 | ss_mode != 0)) | |
4195 | return -EINVAL; | |
1da177e4 | 4196 | |
6c3118c3 CB |
4197 | /* |
4198 | * Return before taking any locks if no actual | |
4199 | * sigaltstack changes were requested. | |
4200 | */ | |
4201 | if (t->sas_ss_sp == (unsigned long)ss_sp && | |
4202 | t->sas_ss_size == ss_size && | |
4203 | t->sas_ss_flags == ss_flags) | |
4204 | return 0; | |
4205 | ||
1bdda24c | 4206 | sigaltstack_lock(); |
407bc16a | 4207 | if (ss_mode == SS_DISABLE) { |
1da177e4 LT |
4208 | ss_size = 0; |
4209 | ss_sp = NULL; | |
4210 | } else { | |
22839869 | 4211 | if (unlikely(ss_size < min_ss_size)) |
1bdda24c TG |
4212 | ret = -ENOMEM; |
4213 | if (!sigaltstack_size_valid(ss_size)) | |
4214 | ret = -ENOMEM; | |
1da177e4 | 4215 | } |
1bdda24c TG |
4216 | if (!ret) { |
4217 | t->sas_ss_sp = (unsigned long) ss_sp; | |
4218 | t->sas_ss_size = ss_size; | |
4219 | t->sas_ss_flags = ss_flags; | |
4220 | } | |
4221 | sigaltstack_unlock(); | |
1da177e4 | 4222 | } |
1bdda24c | 4223 | return ret; |
1da177e4 | 4224 | } |
bcfe8ad8 | 4225 | |
6bf9adfc AV |
4226 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
4227 | { | |
bcfe8ad8 AV |
4228 | stack_t new, old; |
4229 | int err; | |
4230 | if (uss && copy_from_user(&new, uss, sizeof(stack_t))) | |
4231 | return -EFAULT; | |
4232 | err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, | |
22839869 WD |
4233 | current_user_stack_pointer(), |
4234 | MINSIGSTKSZ); | |
bcfe8ad8 AV |
4235 | if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
4236 | err = -EFAULT; | |
4237 | return err; | |
6bf9adfc | 4238 | } |
1da177e4 | 4239 | |
5c49574f AV |
4240 | int restore_altstack(const stack_t __user *uss) |
4241 | { | |
bcfe8ad8 AV |
4242 | stack_t new; |
4243 | if (copy_from_user(&new, uss, sizeof(stack_t))) | |
4244 | return -EFAULT; | |
22839869 WD |
4245 | (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
4246 | MINSIGSTKSZ); | |
5c49574f | 4247 | /* squash all but EFAULT for now */ |
bcfe8ad8 | 4248 | return 0; |
5c49574f AV |
4249 | } |
4250 | ||
c40702c4 AV |
4251 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
4252 | { | |
4253 | struct task_struct *t = current; | |
2a742138 SS |
4254 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
4255 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 4256 | __put_user(t->sas_ss_size, &uss->ss_size); |
97c885d5 | 4257 | return err; |
c40702c4 AV |
4258 | } |
4259 | ||
90268439 | 4260 | #ifdef CONFIG_COMPAT |
6203deb0 DB |
4261 | static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr, |
4262 | compat_stack_t __user *uoss_ptr) | |
90268439 AV |
4263 | { |
4264 | stack_t uss, uoss; | |
4265 | int ret; | |
90268439 AV |
4266 | |
4267 | if (uss_ptr) { | |
4268 | compat_stack_t uss32; | |
90268439 AV |
4269 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
4270 | return -EFAULT; | |
4271 | uss.ss_sp = compat_ptr(uss32.ss_sp); | |
4272 | uss.ss_flags = uss32.ss_flags; | |
4273 | uss.ss_size = uss32.ss_size; | |
4274 | } | |
bcfe8ad8 | 4275 | ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
22839869 WD |
4276 | compat_user_stack_pointer(), |
4277 | COMPAT_MINSIGSTKSZ); | |
90268439 | 4278 | if (ret >= 0 && uoss_ptr) { |
bcfe8ad8 AV |
4279 | compat_stack_t old; |
4280 | memset(&old, 0, sizeof(old)); | |
4281 | old.ss_sp = ptr_to_compat(uoss.ss_sp); | |
4282 | old.ss_flags = uoss.ss_flags; | |
4283 | old.ss_size = uoss.ss_size; | |
4284 | if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) | |
90268439 AV |
4285 | ret = -EFAULT; |
4286 | } | |
4287 | return ret; | |
4288 | } | |
4289 | ||
6203deb0 DB |
4290 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
4291 | const compat_stack_t __user *, uss_ptr, | |
4292 | compat_stack_t __user *, uoss_ptr) | |
4293 | { | |
4294 | return do_compat_sigaltstack(uss_ptr, uoss_ptr); | |
4295 | } | |
4296 | ||
90268439 AV |
4297 | int compat_restore_altstack(const compat_stack_t __user *uss) |
4298 | { | |
6203deb0 | 4299 | int err = do_compat_sigaltstack(uss, NULL); |
90268439 AV |
4300 | /* squash all but -EFAULT for now */ |
4301 | return err == -EFAULT ? err : 0; | |
4302 | } | |
c40702c4 AV |
4303 | |
4304 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) | |
4305 | { | |
441398d3 | 4306 | int err; |
c40702c4 | 4307 | struct task_struct *t = current; |
441398d3 SS |
4308 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
4309 | &uss->ss_sp) | | |
4310 | __put_user(t->sas_ss_flags, &uss->ss_flags) | | |
c40702c4 | 4311 | __put_user(t->sas_ss_size, &uss->ss_size); |
97c885d5 | 4312 | return err; |
c40702c4 | 4313 | } |
90268439 | 4314 | #endif |
1da177e4 LT |
4315 | |
4316 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
4317 | ||
41c57892 RD |
4318 | /** |
4319 | * sys_sigpending - examine pending signals | |
d53238cd | 4320 | * @uset: where mask of pending signal is returned |
41c57892 | 4321 | */ |
d53238cd | 4322 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset) |
1da177e4 | 4323 | { |
d53238cd | 4324 | sigset_t set; |
d53238cd DB |
4325 | |
4326 | if (sizeof(old_sigset_t) > sizeof(*uset)) | |
4327 | return -EINVAL; | |
4328 | ||
b1d294c8 CB |
4329 | do_sigpending(&set); |
4330 | ||
4331 | if (copy_to_user(uset, &set, sizeof(old_sigset_t))) | |
4332 | return -EFAULT; | |
4333 | ||
4334 | return 0; | |
1da177e4 LT |
4335 | } |
4336 | ||
8f13621a AV |
4337 | #ifdef CONFIG_COMPAT |
4338 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) | |
4339 | { | |
4340 | sigset_t set; | |
b1d294c8 CB |
4341 | |
4342 | do_sigpending(&set); | |
4343 | ||
4344 | return put_user(set.sig[0], set32); | |
8f13621a AV |
4345 | } |
4346 | #endif | |
4347 | ||
1da177e4 LT |
4348 | #endif |
4349 | ||
4350 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
41c57892 RD |
4351 | /** |
4352 | * sys_sigprocmask - examine and change blocked signals | |
4353 | * @how: whether to add, remove, or set signals | |
b013c399 | 4354 | * @nset: signals to add or remove (if non-null) |
41c57892 RD |
4355 | * @oset: previous value of signal mask if non-null |
4356 | * | |
5aba085e RD |
4357 | * Some platforms have their own version with special arguments; |
4358 | * others support only sys_rt_sigprocmask. | |
4359 | */ | |
1da177e4 | 4360 | |
b013c399 | 4361 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
b290ebe2 | 4362 | old_sigset_t __user *, oset) |
1da177e4 | 4363 | { |
1da177e4 | 4364 | old_sigset_t old_set, new_set; |
2e4f7c77 | 4365 | sigset_t new_blocked; |
1da177e4 | 4366 | |
b013c399 | 4367 | old_set = current->blocked.sig[0]; |
1da177e4 | 4368 | |
b013c399 ON |
4369 | if (nset) { |
4370 | if (copy_from_user(&new_set, nset, sizeof(*nset))) | |
4371 | return -EFAULT; | |
1da177e4 | 4372 | |
2e4f7c77 | 4373 | new_blocked = current->blocked; |
1da177e4 | 4374 | |
1da177e4 | 4375 | switch (how) { |
1da177e4 | 4376 | case SIG_BLOCK: |
2e4f7c77 | 4377 | sigaddsetmask(&new_blocked, new_set); |
1da177e4 LT |
4378 | break; |
4379 | case SIG_UNBLOCK: | |
2e4f7c77 | 4380 | sigdelsetmask(&new_blocked, new_set); |
1da177e4 LT |
4381 | break; |
4382 | case SIG_SETMASK: | |
2e4f7c77 | 4383 | new_blocked.sig[0] = new_set; |
1da177e4 | 4384 | break; |
2e4f7c77 ON |
4385 | default: |
4386 | return -EINVAL; | |
1da177e4 LT |
4387 | } |
4388 | ||
0c4a8423 | 4389 | set_current_blocked(&new_blocked); |
b013c399 ON |
4390 | } |
4391 | ||
4392 | if (oset) { | |
1da177e4 | 4393 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
b013c399 | 4394 | return -EFAULT; |
1da177e4 | 4395 | } |
b013c399 ON |
4396 | |
4397 | return 0; | |
1da177e4 LT |
4398 | } |
4399 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
4400 | ||
eaca6eae | 4401 | #ifndef CONFIG_ODD_RT_SIGACTION |
41c57892 RD |
4402 | /** |
4403 | * sys_rt_sigaction - alter an action taken by a process | |
4404 | * @sig: signal to be sent | |
f9fa0bc1 RD |
4405 | * @act: new sigaction |
4406 | * @oact: used to save the previous sigaction | |
41c57892 RD |
4407 | * @sigsetsize: size of sigset_t type |
4408 | */ | |
d4e82042 HC |
4409 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
4410 | const struct sigaction __user *, act, | |
4411 | struct sigaction __user *, oact, | |
4412 | size_t, sigsetsize) | |
1da177e4 LT |
4413 | { |
4414 | struct k_sigaction new_sa, old_sa; | |
d8f993b3 | 4415 | int ret; |
1da177e4 LT |
4416 | |
4417 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4418 | if (sigsetsize != sizeof(sigset_t)) | |
d8f993b3 | 4419 | return -EINVAL; |
1da177e4 | 4420 | |
d8f993b3 CB |
4421 | if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) |
4422 | return -EFAULT; | |
1da177e4 LT |
4423 | |
4424 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
d8f993b3 CB |
4425 | if (ret) |
4426 | return ret; | |
1da177e4 | 4427 | |
d8f993b3 CB |
4428 | if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) |
4429 | return -EFAULT; | |
4430 | ||
4431 | return 0; | |
1da177e4 | 4432 | } |
08d32fe5 | 4433 | #ifdef CONFIG_COMPAT |
08d32fe5 AV |
4434 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
4435 | const struct compat_sigaction __user *, act, | |
4436 | struct compat_sigaction __user *, oact, | |
4437 | compat_size_t, sigsetsize) | |
4438 | { | |
4439 | struct k_sigaction new_ka, old_ka; | |
08d32fe5 AV |
4440 | #ifdef __ARCH_HAS_SA_RESTORER |
4441 | compat_uptr_t restorer; | |
4442 | #endif | |
4443 | int ret; | |
4444 | ||
4445 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4446 | if (sigsetsize != sizeof(compat_sigset_t)) | |
4447 | return -EINVAL; | |
4448 | ||
4449 | if (act) { | |
4450 | compat_uptr_t handler; | |
4451 | ret = get_user(handler, &act->sa_handler); | |
4452 | new_ka.sa.sa_handler = compat_ptr(handler); | |
4453 | #ifdef __ARCH_HAS_SA_RESTORER | |
4454 | ret |= get_user(restorer, &act->sa_restorer); | |
4455 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
4456 | #endif | |
3968cf62 | 4457 | ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
3ddc5b46 | 4458 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
08d32fe5 AV |
4459 | if (ret) |
4460 | return -EFAULT; | |
08d32fe5 AV |
4461 | } |
4462 | ||
4463 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4464 | if (!ret && oact) { | |
08d32fe5 AV |
4465 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
4466 | &oact->sa_handler); | |
f454322e DL |
4467 | ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
4468 | sizeof(oact->sa_mask)); | |
3ddc5b46 | 4469 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
08d32fe5 AV |
4470 | #ifdef __ARCH_HAS_SA_RESTORER |
4471 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
4472 | &oact->sa_restorer); | |
4473 | #endif | |
4474 | } | |
4475 | return ret; | |
4476 | } | |
4477 | #endif | |
eaca6eae | 4478 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
1da177e4 | 4479 | |
495dfbf7 AV |
4480 | #ifdef CONFIG_OLD_SIGACTION |
4481 | SYSCALL_DEFINE3(sigaction, int, sig, | |
4482 | const struct old_sigaction __user *, act, | |
4483 | struct old_sigaction __user *, oact) | |
4484 | { | |
4485 | struct k_sigaction new_ka, old_ka; | |
4486 | int ret; | |
4487 | ||
4488 | if (act) { | |
4489 | old_sigset_t mask; | |
96d4f267 | 4490 | if (!access_ok(act, sizeof(*act)) || |
495dfbf7 AV |
4491 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || |
4492 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || | |
4493 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
4494 | __get_user(mask, &act->sa_mask)) | |
4495 | return -EFAULT; | |
4496 | #ifdef __ARCH_HAS_KA_RESTORER | |
4497 | new_ka.ka_restorer = NULL; | |
4498 | #endif | |
4499 | siginitset(&new_ka.sa.sa_mask, mask); | |
4500 | } | |
4501 | ||
4502 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4503 | ||
4504 | if (!ret && oact) { | |
96d4f267 | 4505 | if (!access_ok(oact, sizeof(*oact)) || |
495dfbf7 AV |
4506 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || |
4507 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || | |
4508 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
4509 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
4510 | return -EFAULT; | |
4511 | } | |
4512 | ||
4513 | return ret; | |
4514 | } | |
4515 | #endif | |
4516 | #ifdef CONFIG_COMPAT_OLD_SIGACTION | |
4517 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, | |
4518 | const struct compat_old_sigaction __user *, act, | |
4519 | struct compat_old_sigaction __user *, oact) | |
4520 | { | |
4521 | struct k_sigaction new_ka, old_ka; | |
4522 | int ret; | |
4523 | compat_old_sigset_t mask; | |
4524 | compat_uptr_t handler, restorer; | |
4525 | ||
4526 | if (act) { | |
96d4f267 | 4527 | if (!access_ok(act, sizeof(*act)) || |
495dfbf7 AV |
4528 | __get_user(handler, &act->sa_handler) || |
4529 | __get_user(restorer, &act->sa_restorer) || | |
4530 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || | |
4531 | __get_user(mask, &act->sa_mask)) | |
4532 | return -EFAULT; | |
4533 | ||
4534 | #ifdef __ARCH_HAS_KA_RESTORER | |
4535 | new_ka.ka_restorer = NULL; | |
4536 | #endif | |
4537 | new_ka.sa.sa_handler = compat_ptr(handler); | |
4538 | new_ka.sa.sa_restorer = compat_ptr(restorer); | |
4539 | siginitset(&new_ka.sa.sa_mask, mask); | |
4540 | } | |
4541 | ||
4542 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
4543 | ||
4544 | if (!ret && oact) { | |
96d4f267 | 4545 | if (!access_ok(oact, sizeof(*oact)) || |
495dfbf7 AV |
4546 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), |
4547 | &oact->sa_handler) || | |
4548 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), | |
4549 | &oact->sa_restorer) || | |
4550 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || | |
4551 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) | |
4552 | return -EFAULT; | |
4553 | } | |
4554 | return ret; | |
4555 | } | |
4556 | #endif | |
1da177e4 | 4557 | |
f6187769 | 4558 | #ifdef CONFIG_SGETMASK_SYSCALL |
1da177e4 LT |
4559 | |
4560 | /* | |
4561 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
4562 | */ | |
a5f8fa9e | 4563 | SYSCALL_DEFINE0(sgetmask) |
1da177e4 LT |
4564 | { |
4565 | /* SMP safe */ | |
4566 | return current->blocked.sig[0]; | |
4567 | } | |
4568 | ||
a5f8fa9e | 4569 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
1da177e4 | 4570 | { |
c1095c6d ON |
4571 | int old = current->blocked.sig[0]; |
4572 | sigset_t newset; | |
1da177e4 | 4573 | |
5ba53ff6 | 4574 | siginitset(&newset, newmask); |
c1095c6d | 4575 | set_current_blocked(&newset); |
1da177e4 LT |
4576 | |
4577 | return old; | |
4578 | } | |
f6187769 | 4579 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
1da177e4 LT |
4580 | |
4581 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
4582 | /* | |
4583 | * For backwards compatibility. Functionality superseded by sigaction. | |
4584 | */ | |
a5f8fa9e | 4585 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
1da177e4 LT |
4586 | { |
4587 | struct k_sigaction new_sa, old_sa; | |
4588 | int ret; | |
4589 | ||
4590 | new_sa.sa.sa_handler = handler; | |
4591 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 4592 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
4593 | |
4594 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
4595 | ||
4596 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
4597 | } | |
4598 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
4599 | ||
4600 | #ifdef __ARCH_WANT_SYS_PAUSE | |
4601 | ||
a5f8fa9e | 4602 | SYSCALL_DEFINE0(pause) |
1da177e4 | 4603 | { |
d92fcf05 | 4604 | while (!signal_pending(current)) { |
1df01355 | 4605 | __set_current_state(TASK_INTERRUPTIBLE); |
d92fcf05 ON |
4606 | schedule(); |
4607 | } | |
1da177e4 LT |
4608 | return -ERESTARTNOHAND; |
4609 | } | |
4610 | ||
4611 | #endif | |
4612 | ||
9d8a7652 | 4613 | static int sigsuspend(sigset_t *set) |
68f3f16d | 4614 | { |
68f3f16d AV |
4615 | current->saved_sigmask = current->blocked; |
4616 | set_current_blocked(set); | |
4617 | ||
823dd322 SL |
4618 | while (!signal_pending(current)) { |
4619 | __set_current_state(TASK_INTERRUPTIBLE); | |
4620 | schedule(); | |
4621 | } | |
68f3f16d AV |
4622 | set_restore_sigmask(); |
4623 | return -ERESTARTNOHAND; | |
4624 | } | |
68f3f16d | 4625 | |
41c57892 RD |
4626 | /** |
4627 | * sys_rt_sigsuspend - replace the signal mask for a value with the | |
4628 | * @unewset value until a signal is received | |
4629 | * @unewset: new signal mask value | |
4630 | * @sigsetsize: size of sigset_t type | |
4631 | */ | |
d4e82042 | 4632 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
150256d8 DW |
4633 | { |
4634 | sigset_t newset; | |
4635 | ||
4636 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4637 | if (sigsetsize != sizeof(sigset_t)) | |
4638 | return -EINVAL; | |
4639 | ||
4640 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
4641 | return -EFAULT; | |
68f3f16d | 4642 | return sigsuspend(&newset); |
150256d8 | 4643 | } |
ad4b65a4 AV |
4644 | |
4645 | #ifdef CONFIG_COMPAT | |
4646 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) | |
4647 | { | |
ad4b65a4 | 4648 | sigset_t newset; |
ad4b65a4 AV |
4649 | |
4650 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
4651 | if (sigsetsize != sizeof(sigset_t)) | |
4652 | return -EINVAL; | |
4653 | ||
3968cf62 | 4654 | if (get_compat_sigset(&newset, unewset)) |
ad4b65a4 | 4655 | return -EFAULT; |
ad4b65a4 | 4656 | return sigsuspend(&newset); |
ad4b65a4 AV |
4657 | } |
4658 | #endif | |
150256d8 | 4659 | |
0a0e8cdf AV |
4660 | #ifdef CONFIG_OLD_SIGSUSPEND |
4661 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) | |
4662 | { | |
4663 | sigset_t blocked; | |
4664 | siginitset(&blocked, mask); | |
4665 | return sigsuspend(&blocked); | |
4666 | } | |
4667 | #endif | |
4668 | #ifdef CONFIG_OLD_SIGSUSPEND3 | |
4669 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) | |
4670 | { | |
4671 | sigset_t blocked; | |
4672 | siginitset(&blocked, mask); | |
4673 | return sigsuspend(&blocked); | |
4674 | } | |
4675 | #endif | |
150256d8 | 4676 | |
52f5684c | 4677 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
f269fdd1 DH |
4678 | { |
4679 | return NULL; | |
4680 | } | |
4681 | ||
ae7795bc | 4682 | static inline void siginfo_buildtime_checks(void) |
1da177e4 | 4683 | { |
aba1be2f | 4684 | BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE); |
41b27154 | 4685 | |
ae7795bc EB |
4686 | /* Verify the offsets in the two siginfos match */ |
4687 | #define CHECK_OFFSET(field) \ | |
4688 | BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field)) | |
4689 | ||
4690 | /* kill */ | |
4691 | CHECK_OFFSET(si_pid); | |
4692 | CHECK_OFFSET(si_uid); | |
4693 | ||
4694 | /* timer */ | |
4695 | CHECK_OFFSET(si_tid); | |
4696 | CHECK_OFFSET(si_overrun); | |
4697 | CHECK_OFFSET(si_value); | |
4698 | ||
4699 | /* rt */ | |
4700 | CHECK_OFFSET(si_pid); | |
4701 | CHECK_OFFSET(si_uid); | |
4702 | CHECK_OFFSET(si_value); | |
4703 | ||
4704 | /* sigchld */ | |
4705 | CHECK_OFFSET(si_pid); | |
4706 | CHECK_OFFSET(si_uid); | |
4707 | CHECK_OFFSET(si_status); | |
4708 | CHECK_OFFSET(si_utime); | |
4709 | CHECK_OFFSET(si_stime); | |
4710 | ||
4711 | /* sigfault */ | |
4712 | CHECK_OFFSET(si_addr); | |
add0b32e | 4713 | CHECK_OFFSET(si_trapno); |
ae7795bc EB |
4714 | CHECK_OFFSET(si_addr_lsb); |
4715 | CHECK_OFFSET(si_lower); | |
4716 | CHECK_OFFSET(si_upper); | |
4717 | CHECK_OFFSET(si_pkey); | |
0683b531 EB |
4718 | CHECK_OFFSET(si_perf_data); |
4719 | CHECK_OFFSET(si_perf_type); | |
78ed93d7 | 4720 | CHECK_OFFSET(si_perf_flags); |
ae7795bc EB |
4721 | |
4722 | /* sigpoll */ | |
4723 | CHECK_OFFSET(si_band); | |
4724 | CHECK_OFFSET(si_fd); | |
4725 | ||
4726 | /* sigsys */ | |
4727 | CHECK_OFFSET(si_call_addr); | |
4728 | CHECK_OFFSET(si_syscall); | |
4729 | CHECK_OFFSET(si_arch); | |
4730 | #undef CHECK_OFFSET | |
70f1b0d3 EB |
4731 | |
4732 | /* usb asyncio */ | |
4733 | BUILD_BUG_ON(offsetof(struct siginfo, si_pid) != | |
4734 | offsetof(struct siginfo, si_addr)); | |
4735 | if (sizeof(int) == sizeof(void __user *)) { | |
4736 | BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) != | |
4737 | sizeof(void __user *)); | |
4738 | } else { | |
4739 | BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) + | |
4740 | sizeof_field(struct siginfo, si_uid)) != | |
4741 | sizeof(void __user *)); | |
4742 | BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) != | |
4743 | offsetof(struct siginfo, si_uid)); | |
4744 | } | |
4745 | #ifdef CONFIG_COMPAT | |
4746 | BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) != | |
4747 | offsetof(struct compat_siginfo, si_addr)); | |
4748 | BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != | |
4749 | sizeof(compat_uptr_t)); | |
4750 | BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != | |
4751 | sizeof_field(struct siginfo, si_pid)); | |
4752 | #endif | |
ae7795bc EB |
4753 | } |
4754 | ||
4755 | void __init signals_init(void) | |
4756 | { | |
4757 | siginfo_buildtime_checks(); | |
4758 | ||
5f58c398 | 4759 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT); |
1da177e4 | 4760 | } |
67fc4e0c JW |
4761 | |
4762 | #ifdef CONFIG_KGDB_KDB | |
4763 | #include <linux/kdb.h> | |
4764 | /* | |
0b44bf9a | 4765 | * kdb_send_sig - Allows kdb to send signals without exposing |
67fc4e0c JW |
4766 | * signal internals. This function checks if the required locks are |
4767 | * available before calling the main signal code, to avoid kdb | |
4768 | * deadlocks. | |
4769 | */ | |
0b44bf9a | 4770 | void kdb_send_sig(struct task_struct *t, int sig) |
67fc4e0c JW |
4771 | { |
4772 | static struct task_struct *kdb_prev_t; | |
0b44bf9a | 4773 | int new_t, ret; |
67fc4e0c JW |
4774 | if (!spin_trylock(&t->sighand->siglock)) { |
4775 | kdb_printf("Can't do kill command now.\n" | |
4776 | "The sigmask lock is held somewhere else in " | |
4777 | "kernel, try again later\n"); | |
4778 | return; | |
4779 | } | |
67fc4e0c JW |
4780 | new_t = kdb_prev_t != t; |
4781 | kdb_prev_t = t; | |
b03fbd4f | 4782 | if (!task_is_running(t) && new_t) { |
0b44bf9a | 4783 | spin_unlock(&t->sighand->siglock); |
67fc4e0c JW |
4784 | kdb_printf("Process is not RUNNING, sending a signal from " |
4785 | "kdb risks deadlock\n" | |
4786 | "on the run queue locks. " | |
4787 | "The signal has _not_ been sent.\n" | |
4788 | "Reissue the kill command if you want to risk " | |
4789 | "the deadlock.\n"); | |
4790 | return; | |
4791 | } | |
157cc181 | 4792 | ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID); |
0b44bf9a EB |
4793 | spin_unlock(&t->sighand->siglock); |
4794 | if (ret) | |
67fc4e0c JW |
4795 | kdb_printf("Fail to deliver Signal %d to process %d.\n", |
4796 | sig, t->pid); | |
4797 | else | |
4798 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); | |
4799 | } | |
4800 | #endif /* CONFIG_KGDB_KDB */ |