| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 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 | |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/export.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/sched/mm.h> |
| 18 | #include <linux/sched/user.h> |
| 19 | #include <linux/sched/debug.h> |
| 20 | #include <linux/sched/task.h> |
| 21 | #include <linux/sched/task_stack.h> |
| 22 | #include <linux/sched/cputime.h> |
| 23 | #include <linux/file.h> |
| 24 | #include <linux/fs.h> |
| 25 | #include <linux/mm.h> |
| 26 | #include <linux/proc_fs.h> |
| 27 | #include <linux/tty.h> |
| 28 | #include <linux/binfmts.h> |
| 29 | #include <linux/coredump.h> |
| 30 | #include <linux/security.h> |
| 31 | #include <linux/syscalls.h> |
| 32 | #include <linux/ptrace.h> |
| 33 | #include <linux/signal.h> |
| 34 | #include <linux/signalfd.h> |
| 35 | #include <linux/ratelimit.h> |
| 36 | #include <linux/task_work.h> |
| 37 | #include <linux/capability.h> |
| 38 | #include <linux/freezer.h> |
| 39 | #include <linux/pid_namespace.h> |
| 40 | #include <linux/nsproxy.h> |
| 41 | #include <linux/user_namespace.h> |
| 42 | #include <linux/uprobes.h> |
| 43 | #include <linux/compat.h> |
| 44 | #include <linux/cn_proc.h> |
| 45 | #include <linux/compiler.h> |
| 46 | #include <linux/posix-timers.h> |
| 47 | #include <linux/cgroup.h> |
| 48 | #include <linux/audit.h> |
| 49 | #include <linux/sysctl.h> |
| 50 | |
| 51 | #define CREATE_TRACE_POINTS |
| 52 | #include <trace/events/signal.h> |
| 53 | |
| 54 | #include <asm/param.h> |
| 55 | #include <linux/uaccess.h> |
| 56 | #include <asm/unistd.h> |
| 57 | #include <asm/siginfo.h> |
| 58 | #include <asm/cacheflush.h> |
| 59 | #include <asm/syscall.h> /* for syscall_get_* */ |
| 60 | |
| 61 | /* |
| 62 | * SLAB caches for signal bits. |
| 63 | */ |
| 64 | |
| 65 | static struct kmem_cache *sigqueue_cachep; |
| 66 | |
| 67 | int print_fatal_signals __read_mostly; |
| 68 | |
| 69 | static void __user *sig_handler(struct task_struct *t, int sig) |
| 70 | { |
| 71 | return t->sighand->action[sig - 1].sa.sa_handler; |
| 72 | } |
| 73 | |
| 74 | static inline bool sig_handler_ignored(void __user *handler, int sig) |
| 75 | { |
| 76 | /* Is it explicitly or implicitly ignored? */ |
| 77 | return handler == SIG_IGN || |
| 78 | (handler == SIG_DFL && sig_kernel_ignore(sig)); |
| 79 | } |
| 80 | |
| 81 | static bool sig_task_ignored(struct task_struct *t, int sig, bool force) |
| 82 | { |
| 83 | void __user *handler; |
| 84 | |
| 85 | handler = sig_handler(t, sig); |
| 86 | |
| 87 | /* SIGKILL and SIGSTOP may not be sent to the global init */ |
| 88 | if (unlikely(is_global_init(t) && sig_kernel_only(sig))) |
| 89 | return true; |
| 90 | |
| 91 | if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && |
| 92 | handler == SIG_DFL && !(force && sig_kernel_only(sig))) |
| 93 | return true; |
| 94 | |
| 95 | /* Only allow kernel generated signals to this kthread */ |
| 96 | if (unlikely((t->flags & PF_KTHREAD) && |
| 97 | (handler == SIG_KTHREAD_KERNEL) && !force)) |
| 98 | return true; |
| 99 | |
| 100 | return sig_handler_ignored(handler, sig); |
| 101 | } |
| 102 | |
| 103 | static bool sig_ignored(struct task_struct *t, int sig, bool force) |
| 104 | { |
| 105 | /* |
| 106 | * Blocked signals are never ignored, since the |
| 107 | * signal handler may change by the time it is |
| 108 | * unblocked. |
| 109 | */ |
| 110 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
| 111 | return false; |
| 112 | |
| 113 | /* |
| 114 | * Tracers may want to know about even ignored signal unless it |
| 115 | * is SIGKILL which can't be reported anyway but can be ignored |
| 116 | * by SIGNAL_UNKILLABLE task. |
| 117 | */ |
| 118 | if (t->ptrace && sig != SIGKILL) |
| 119 | return false; |
| 120 | |
| 121 | return sig_task_ignored(t, sig, force); |
| 122 | } |
| 123 | |
| 124 | /* |
| 125 | * Re-calculate pending state from the set of locally pending |
| 126 | * signals, globally pending signals, and blocked signals. |
| 127 | */ |
| 128 | static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked) |
| 129 | { |
| 130 | unsigned long ready; |
| 131 | long i; |
| 132 | |
| 133 | switch (_NSIG_WORDS) { |
| 134 | default: |
| 135 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) |
| 136 | ready |= signal->sig[i] &~ blocked->sig[i]; |
| 137 | break; |
| 138 | |
| 139 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; |
| 140 | ready |= signal->sig[2] &~ blocked->sig[2]; |
| 141 | ready |= signal->sig[1] &~ blocked->sig[1]; |
| 142 | ready |= signal->sig[0] &~ blocked->sig[0]; |
| 143 | break; |
| 144 | |
| 145 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; |
| 146 | ready |= signal->sig[0] &~ blocked->sig[0]; |
| 147 | break; |
| 148 | |
| 149 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; |
| 150 | } |
| 151 | return ready != 0; |
| 152 | } |
| 153 | |
| 154 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) |
| 155 | |
| 156 | static bool recalc_sigpending_tsk(struct task_struct *t) |
| 157 | { |
| 158 | if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) || |
| 159 | PENDING(&t->pending, &t->blocked) || |
| 160 | PENDING(&t->signal->shared_pending, &t->blocked) || |
| 161 | cgroup_task_frozen(t)) { |
| 162 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
| 163 | return true; |
| 164 | } |
| 165 | |
| 166 | /* |
| 167 | * We must never clear the flag in another thread, or in current |
| 168 | * when it's possible the current syscall is returning -ERESTART*. |
| 169 | * So we don't clear it here, and only callers who know they should do. |
| 170 | */ |
| 171 | return false; |
| 172 | } |
| 173 | |
| 174 | /* |
| 175 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. |
| 176 | * This is superfluous when called on current, the wakeup is a harmless no-op. |
| 177 | */ |
| 178 | void recalc_sigpending_and_wake(struct task_struct *t) |
| 179 | { |
| 180 | if (recalc_sigpending_tsk(t)) |
| 181 | signal_wake_up(t, 0); |
| 182 | } |
| 183 | |
| 184 | void recalc_sigpending(void) |
| 185 | { |
| 186 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
| 187 | clear_thread_flag(TIF_SIGPENDING); |
| 188 | |
| 189 | } |
| 190 | EXPORT_SYMBOL(recalc_sigpending); |
| 191 | |
| 192 | void calculate_sigpending(void) |
| 193 | { |
| 194 | /* Have any signals or users of TIF_SIGPENDING been delayed |
| 195 | * until after fork? |
| 196 | */ |
| 197 | spin_lock_irq(¤t->sighand->siglock); |
| 198 | set_tsk_thread_flag(current, TIF_SIGPENDING); |
| 199 | recalc_sigpending(); |
| 200 | spin_unlock_irq(¤t->sighand->siglock); |
| 201 | } |
| 202 | |
| 203 | /* Given the mask, find the first available signal that should be serviced. */ |
| 204 | |
| 205 | #define SYNCHRONOUS_MASK \ |
| 206 | (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \ |
| 207 | sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS)) |
| 208 | |
| 209 | int next_signal(struct sigpending *pending, sigset_t *mask) |
| 210 | { |
| 211 | unsigned long i, *s, *m, x; |
| 212 | int sig = 0; |
| 213 | |
| 214 | s = pending->signal.sig; |
| 215 | m = mask->sig; |
| 216 | |
| 217 | /* |
| 218 | * Handle the first word specially: it contains the |
| 219 | * synchronous signals that need to be dequeued first. |
| 220 | */ |
| 221 | x = *s &~ *m; |
| 222 | if (x) { |
| 223 | if (x & SYNCHRONOUS_MASK) |
| 224 | x &= SYNCHRONOUS_MASK; |
| 225 | sig = ffz(~x) + 1; |
| 226 | return sig; |
| 227 | } |
| 228 | |
| 229 | switch (_NSIG_WORDS) { |
| 230 | default: |
| 231 | for (i = 1; i < _NSIG_WORDS; ++i) { |
| 232 | x = *++s &~ *++m; |
| 233 | if (!x) |
| 234 | continue; |
| 235 | sig = ffz(~x) + i*_NSIG_BPW + 1; |
| 236 | break; |
| 237 | } |
| 238 | break; |
| 239 | |
| 240 | case 2: |
| 241 | x = s[1] &~ m[1]; |
| 242 | if (!x) |
| 243 | break; |
| 244 | sig = ffz(~x) + _NSIG_BPW + 1; |
| 245 | break; |
| 246 | |
| 247 | case 1: |
| 248 | /* Nothing to do */ |
| 249 | break; |
| 250 | } |
| 251 | |
| 252 | return sig; |
| 253 | } |
| 254 | |
| 255 | static inline void print_dropped_signal(int sig) |
| 256 | { |
| 257 | static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); |
| 258 | |
| 259 | if (!print_fatal_signals) |
| 260 | return; |
| 261 | |
| 262 | if (!__ratelimit(&ratelimit_state)) |
| 263 | return; |
| 264 | |
| 265 | pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", |
| 266 | current->comm, current->pid, sig); |
| 267 | } |
| 268 | |
| 269 | /** |
| 270 | * task_set_jobctl_pending - set jobctl pending bits |
| 271 | * @task: target task |
| 272 | * @mask: pending bits to set |
| 273 | * |
| 274 | * Clear @mask from @task->jobctl. @mask must be subset of |
| 275 | * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK | |
| 276 | * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is |
| 277 | * cleared. If @task is already being killed or exiting, this function |
| 278 | * becomes noop. |
| 279 | * |
| 280 | * CONTEXT: |
| 281 | * Must be called with @task->sighand->siglock held. |
| 282 | * |
| 283 | * RETURNS: |
| 284 | * %true if @mask is set, %false if made noop because @task was dying. |
| 285 | */ |
| 286 | bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) |
| 287 | { |
| 288 | BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME | |
| 289 | JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); |
| 290 | BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); |
| 291 | |
| 292 | if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) |
| 293 | return false; |
| 294 | |
| 295 | if (mask & JOBCTL_STOP_SIGMASK) |
| 296 | task->jobctl &= ~JOBCTL_STOP_SIGMASK; |
| 297 | |
| 298 | task->jobctl |= mask; |
| 299 | return true; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * task_clear_jobctl_trapping - clear jobctl trapping bit |
| 304 | * @task: target task |
| 305 | * |
| 306 | * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED. |
| 307 | * Clear it and wake up the ptracer. Note that we don't need any further |
| 308 | * locking. @task->siglock guarantees that @task->parent points to the |
| 309 | * ptracer. |
| 310 | * |
| 311 | * CONTEXT: |
| 312 | * Must be called with @task->sighand->siglock held. |
| 313 | */ |
| 314 | void task_clear_jobctl_trapping(struct task_struct *task) |
| 315 | { |
| 316 | if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { |
| 317 | task->jobctl &= ~JOBCTL_TRAPPING; |
| 318 | smp_mb(); /* advised by wake_up_bit() */ |
| 319 | wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | /** |
| 324 | * task_clear_jobctl_pending - clear jobctl pending bits |
| 325 | * @task: target task |
| 326 | * @mask: pending bits to clear |
| 327 | * |
| 328 | * Clear @mask from @task->jobctl. @mask must be subset of |
| 329 | * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other |
| 330 | * STOP bits are cleared together. |
| 331 | * |
| 332 | * If clearing of @mask leaves no stop or trap pending, this function calls |
| 333 | * task_clear_jobctl_trapping(). |
| 334 | * |
| 335 | * CONTEXT: |
| 336 | * Must be called with @task->sighand->siglock held. |
| 337 | */ |
| 338 | void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) |
| 339 | { |
| 340 | BUG_ON(mask & ~JOBCTL_PENDING_MASK); |
| 341 | |
| 342 | if (mask & JOBCTL_STOP_PENDING) |
| 343 | mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED; |
| 344 | |
| 345 | task->jobctl &= ~mask; |
| 346 | |
| 347 | if (!(task->jobctl & JOBCTL_PENDING_MASK)) |
| 348 | task_clear_jobctl_trapping(task); |
| 349 | } |
| 350 | |
| 351 | /** |
| 352 | * task_participate_group_stop - participate in a group stop |
| 353 | * @task: task participating in a group stop |
| 354 | * |
| 355 | * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. |
| 356 | * Group stop states are cleared and the group stop count is consumed if |
| 357 | * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group |
| 358 | * stop, the appropriate `SIGNAL_*` flags are set. |
| 359 | * |
| 360 | * CONTEXT: |
| 361 | * Must be called with @task->sighand->siglock held. |
| 362 | * |
| 363 | * RETURNS: |
| 364 | * %true if group stop completion should be notified to the parent, %false |
| 365 | * otherwise. |
| 366 | */ |
| 367 | static bool task_participate_group_stop(struct task_struct *task) |
| 368 | { |
| 369 | struct signal_struct *sig = task->signal; |
| 370 | bool consume = task->jobctl & JOBCTL_STOP_CONSUME; |
| 371 | |
| 372 | WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING)); |
| 373 | |
| 374 | task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING); |
| 375 | |
| 376 | if (!consume) |
| 377 | return false; |
| 378 | |
| 379 | if (!WARN_ON_ONCE(sig->group_stop_count == 0)) |
| 380 | sig->group_stop_count--; |
| 381 | |
| 382 | /* |
| 383 | * Tell the caller to notify completion iff we are entering into a |
| 384 | * fresh group stop. Read comment in do_signal_stop() for details. |
| 385 | */ |
| 386 | if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) { |
| 387 | signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED); |
| 388 | return true; |
| 389 | } |
| 390 | return false; |
| 391 | } |
| 392 | |
| 393 | void task_join_group_stop(struct task_struct *task) |
| 394 | { |
| 395 | unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK; |
| 396 | struct signal_struct *sig = current->signal; |
| 397 | |
| 398 | if (sig->group_stop_count) { |
| 399 | sig->group_stop_count++; |
| 400 | mask |= JOBCTL_STOP_CONSUME; |
| 401 | } else if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
| 402 | return; |
| 403 | |
| 404 | /* Have the new thread join an on-going signal group stop */ |
| 405 | task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING); |
| 406 | } |
| 407 | |
| 408 | /* |
| 409 | * allocate a new signal queue record |
| 410 | * - this may be called without locks if and only if t == current, otherwise an |
| 411 | * appropriate lock must be held to stop the target task from exiting |
| 412 | */ |
| 413 | static struct sigqueue * |
| 414 | __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags, |
| 415 | int override_rlimit, const unsigned int sigqueue_flags) |
| 416 | { |
| 417 | struct sigqueue *q = NULL; |
| 418 | struct ucounts *ucounts; |
| 419 | long sigpending; |
| 420 | |
| 421 | /* |
| 422 | * Protect access to @t credentials. This can go away when all |
| 423 | * callers hold rcu read lock. |
| 424 | * |
| 425 | * NOTE! A pending signal will hold on to the user refcount, |
| 426 | * and we get/put the refcount only when the sigpending count |
| 427 | * changes from/to zero. |
| 428 | */ |
| 429 | rcu_read_lock(); |
| 430 | ucounts = task_ucounts(t); |
| 431 | sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
| 432 | rcu_read_unlock(); |
| 433 | if (!sigpending) |
| 434 | return NULL; |
| 435 | |
| 436 | if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) { |
| 437 | q = kmem_cache_alloc(sigqueue_cachep, gfp_flags); |
| 438 | } else { |
| 439 | print_dropped_signal(sig); |
| 440 | } |
| 441 | |
| 442 | if (unlikely(q == NULL)) { |
| 443 | dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING); |
| 444 | } else { |
| 445 | INIT_LIST_HEAD(&q->list); |
| 446 | q->flags = sigqueue_flags; |
| 447 | q->ucounts = ucounts; |
| 448 | } |
| 449 | return q; |
| 450 | } |
| 451 | |
| 452 | static void __sigqueue_free(struct sigqueue *q) |
| 453 | { |
| 454 | if (q->flags & SIGQUEUE_PREALLOC) |
| 455 | return; |
| 456 | if (q->ucounts) { |
| 457 | dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING); |
| 458 | q->ucounts = NULL; |
| 459 | } |
| 460 | kmem_cache_free(sigqueue_cachep, q); |
| 461 | } |
| 462 | |
| 463 | void flush_sigqueue(struct sigpending *queue) |
| 464 | { |
| 465 | struct sigqueue *q; |
| 466 | |
| 467 | sigemptyset(&queue->signal); |
| 468 | while (!list_empty(&queue->list)) { |
| 469 | q = list_entry(queue->list.next, struct sigqueue , list); |
| 470 | list_del_init(&q->list); |
| 471 | __sigqueue_free(q); |
| 472 | } |
| 473 | } |
| 474 | |
| 475 | /* |
| 476 | * Flush all pending signals for this kthread. |
| 477 | */ |
| 478 | void flush_signals(struct task_struct *t) |
| 479 | { |
| 480 | unsigned long flags; |
| 481 | |
| 482 | spin_lock_irqsave(&t->sighand->siglock, flags); |
| 483 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
| 484 | flush_sigqueue(&t->pending); |
| 485 | flush_sigqueue(&t->signal->shared_pending); |
| 486 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
| 487 | } |
| 488 | EXPORT_SYMBOL(flush_signals); |
| 489 | |
| 490 | #ifdef CONFIG_POSIX_TIMERS |
| 491 | static void __flush_itimer_signals(struct sigpending *pending) |
| 492 | { |
| 493 | sigset_t signal, retain; |
| 494 | struct sigqueue *q, *n; |
| 495 | |
| 496 | signal = pending->signal; |
| 497 | sigemptyset(&retain); |
| 498 | |
| 499 | list_for_each_entry_safe(q, n, &pending->list, list) { |
| 500 | int sig = q->info.si_signo; |
| 501 | |
| 502 | if (likely(q->info.si_code != SI_TIMER)) { |
| 503 | sigaddset(&retain, sig); |
| 504 | } else { |
| 505 | sigdelset(&signal, sig); |
| 506 | list_del_init(&q->list); |
| 507 | __sigqueue_free(q); |
| 508 | } |
| 509 | } |
| 510 | |
| 511 | sigorsets(&pending->signal, &signal, &retain); |
| 512 | } |
| 513 | |
| 514 | void flush_itimer_signals(void) |
| 515 | { |
| 516 | struct task_struct *tsk = current; |
| 517 | unsigned long flags; |
| 518 | |
| 519 | spin_lock_irqsave(&tsk->sighand->siglock, flags); |
| 520 | __flush_itimer_signals(&tsk->pending); |
| 521 | __flush_itimer_signals(&tsk->signal->shared_pending); |
| 522 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); |
| 523 | } |
| 524 | #endif |
| 525 | |
| 526 | void ignore_signals(struct task_struct *t) |
| 527 | { |
| 528 | int i; |
| 529 | |
| 530 | for (i = 0; i < _NSIG; ++i) |
| 531 | t->sighand->action[i].sa.sa_handler = SIG_IGN; |
| 532 | |
| 533 | flush_signals(t); |
| 534 | } |
| 535 | |
| 536 | /* |
| 537 | * Flush all handlers for a task. |
| 538 | */ |
| 539 | |
| 540 | void |
| 541 | flush_signal_handlers(struct task_struct *t, int force_default) |
| 542 | { |
| 543 | int i; |
| 544 | struct k_sigaction *ka = &t->sighand->action[0]; |
| 545 | for (i = _NSIG ; i != 0 ; i--) { |
| 546 | if (force_default || ka->sa.sa_handler != SIG_IGN) |
| 547 | ka->sa.sa_handler = SIG_DFL; |
| 548 | ka->sa.sa_flags = 0; |
| 549 | #ifdef __ARCH_HAS_SA_RESTORER |
| 550 | ka->sa.sa_restorer = NULL; |
| 551 | #endif |
| 552 | sigemptyset(&ka->sa.sa_mask); |
| 553 | ka++; |
| 554 | } |
| 555 | } |
| 556 | |
| 557 | bool unhandled_signal(struct task_struct *tsk, int sig) |
| 558 | { |
| 559 | void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler; |
| 560 | if (is_global_init(tsk)) |
| 561 | return true; |
| 562 | |
| 563 | if (handler != SIG_IGN && handler != SIG_DFL) |
| 564 | return false; |
| 565 | |
| 566 | /* If dying, we handle all new signals by ignoring them */ |
| 567 | if (fatal_signal_pending(tsk)) |
| 568 | return false; |
| 569 | |
| 570 | /* if ptraced, let the tracer determine */ |
| 571 | return !tsk->ptrace; |
| 572 | } |
| 573 | |
| 574 | static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info, |
| 575 | bool *resched_timer) |
| 576 | { |
| 577 | struct sigqueue *q, *first = NULL; |
| 578 | |
| 579 | /* |
| 580 | * Collect the siginfo appropriate to this signal. Check if |
| 581 | * there is another siginfo for the same signal. |
| 582 | */ |
| 583 | list_for_each_entry(q, &list->list, list) { |
| 584 | if (q->info.si_signo == sig) { |
| 585 | if (first) |
| 586 | goto still_pending; |
| 587 | first = q; |
| 588 | } |
| 589 | } |
| 590 | |
| 591 | sigdelset(&list->signal, sig); |
| 592 | |
| 593 | if (first) { |
| 594 | still_pending: |
| 595 | list_del_init(&first->list); |
| 596 | copy_siginfo(info, &first->info); |
| 597 | |
| 598 | *resched_timer = |
| 599 | (first->flags & SIGQUEUE_PREALLOC) && |
| 600 | (info->si_code == SI_TIMER) && |
| 601 | (info->si_sys_private); |
| 602 | |
| 603 | __sigqueue_free(first); |
| 604 | } else { |
| 605 | /* |
| 606 | * Ok, it wasn't in the queue. This must be |
| 607 | * a fast-pathed signal or we must have been |
| 608 | * out of queue space. So zero out the info. |
| 609 | */ |
| 610 | clear_siginfo(info); |
| 611 | info->si_signo = sig; |
| 612 | info->si_errno = 0; |
| 613 | info->si_code = SI_USER; |
| 614 | info->si_pid = 0; |
| 615 | info->si_uid = 0; |
| 616 | } |
| 617 | } |
| 618 | |
| 619 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, |
| 620 | kernel_siginfo_t *info, bool *resched_timer) |
| 621 | { |
| 622 | int sig = next_signal(pending, mask); |
| 623 | |
| 624 | if (sig) |
| 625 | collect_signal(sig, pending, info, resched_timer); |
| 626 | return sig; |
| 627 | } |
| 628 | |
| 629 | /* |
| 630 | * Dequeue a signal and return the element to the caller, which is |
| 631 | * expected to free it. |
| 632 | * |
| 633 | * All callers have to hold the siglock. |
| 634 | */ |
| 635 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, |
| 636 | kernel_siginfo_t *info, enum pid_type *type) |
| 637 | { |
| 638 | bool resched_timer = false; |
| 639 | int signr; |
| 640 | |
| 641 | /* We only dequeue private signals from ourselves, we don't let |
| 642 | * signalfd steal them |
| 643 | */ |
| 644 | *type = PIDTYPE_PID; |
| 645 | signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer); |
| 646 | if (!signr) { |
| 647 | *type = PIDTYPE_TGID; |
| 648 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
| 649 | mask, info, &resched_timer); |
| 650 | #ifdef CONFIG_POSIX_TIMERS |
| 651 | /* |
| 652 | * itimer signal ? |
| 653 | * |
| 654 | * itimers are process shared and we restart periodic |
| 655 | * itimers in the signal delivery path to prevent DoS |
| 656 | * attacks in the high resolution timer case. This is |
| 657 | * compliant with the old way of self-restarting |
| 658 | * itimers, as the SIGALRM is a legacy signal and only |
| 659 | * queued once. Changing the restart behaviour to |
| 660 | * restart the timer in the signal dequeue path is |
| 661 | * reducing the timer noise on heavy loaded !highres |
| 662 | * systems too. |
| 663 | */ |
| 664 | if (unlikely(signr == SIGALRM)) { |
| 665 | struct hrtimer *tmr = &tsk->signal->real_timer; |
| 666 | |
| 667 | if (!hrtimer_is_queued(tmr) && |
| 668 | tsk->signal->it_real_incr != 0) { |
| 669 | hrtimer_forward(tmr, tmr->base->get_time(), |
| 670 | tsk->signal->it_real_incr); |
| 671 | hrtimer_restart(tmr); |
| 672 | } |
| 673 | } |
| 674 | #endif |
| 675 | } |
| 676 | |
| 677 | recalc_sigpending(); |
| 678 | if (!signr) |
| 679 | return 0; |
| 680 | |
| 681 | if (unlikely(sig_kernel_stop(signr))) { |
| 682 | /* |
| 683 | * Set a marker that we have dequeued a stop signal. Our |
| 684 | * caller might release the siglock and then the pending |
| 685 | * stop signal it is about to process is no longer in the |
| 686 | * pending bitmasks, but must still be cleared by a SIGCONT |
| 687 | * (and overruled by a SIGKILL). So those cases clear this |
| 688 | * shared flag after we've set it. Note that this flag may |
| 689 | * remain set after the signal we return is ignored or |
| 690 | * handled. That doesn't matter because its only purpose |
| 691 | * is to alert stop-signal processing code when another |
| 692 | * processor has come along and cleared the flag. |
| 693 | */ |
| 694 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
| 695 | } |
| 696 | #ifdef CONFIG_POSIX_TIMERS |
| 697 | if (resched_timer) { |
| 698 | /* |
| 699 | * Release the siglock to ensure proper locking order |
| 700 | * of timer locks outside of siglocks. Note, we leave |
| 701 | * irqs disabled here, since the posix-timers code is |
| 702 | * about to disable them again anyway. |
| 703 | */ |
| 704 | spin_unlock(&tsk->sighand->siglock); |
| 705 | posixtimer_rearm(info); |
| 706 | spin_lock(&tsk->sighand->siglock); |
| 707 | |
| 708 | /* Don't expose the si_sys_private value to userspace */ |
| 709 | info->si_sys_private = 0; |
| 710 | } |
| 711 | #endif |
| 712 | return signr; |
| 713 | } |
| 714 | EXPORT_SYMBOL_GPL(dequeue_signal); |
| 715 | |
| 716 | static int dequeue_synchronous_signal(kernel_siginfo_t *info) |
| 717 | { |
| 718 | struct task_struct *tsk = current; |
| 719 | struct sigpending *pending = &tsk->pending; |
| 720 | struct sigqueue *q, *sync = NULL; |
| 721 | |
| 722 | /* |
| 723 | * Might a synchronous signal be in the queue? |
| 724 | */ |
| 725 | if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) |
| 726 | return 0; |
| 727 | |
| 728 | /* |
| 729 | * Return the first synchronous signal in the queue. |
| 730 | */ |
| 731 | list_for_each_entry(q, &pending->list, list) { |
| 732 | /* Synchronous signals have a positive si_code */ |
| 733 | if ((q->info.si_code > SI_USER) && |
| 734 | (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) { |
| 735 | sync = q; |
| 736 | goto next; |
| 737 | } |
| 738 | } |
| 739 | return 0; |
| 740 | next: |
| 741 | /* |
| 742 | * Check if there is another siginfo for the same signal. |
| 743 | */ |
| 744 | list_for_each_entry_continue(q, &pending->list, list) { |
| 745 | if (q->info.si_signo == sync->info.si_signo) |
| 746 | goto still_pending; |
| 747 | } |
| 748 | |
| 749 | sigdelset(&pending->signal, sync->info.si_signo); |
| 750 | recalc_sigpending(); |
| 751 | still_pending: |
| 752 | list_del_init(&sync->list); |
| 753 | copy_siginfo(info, &sync->info); |
| 754 | __sigqueue_free(sync); |
| 755 | return info->si_signo; |
| 756 | } |
| 757 | |
| 758 | /* |
| 759 | * Tell a process that it has a new active signal.. |
| 760 | * |
| 761 | * NOTE! we rely on the previous spin_lock to |
| 762 | * lock interrupts for us! We can only be called with |
| 763 | * "siglock" held, and the local interrupt must |
| 764 | * have been disabled when that got acquired! |
| 765 | * |
| 766 | * No need to set need_resched since signal event passing |
| 767 | * goes through ->blocked |
| 768 | */ |
| 769 | void signal_wake_up_state(struct task_struct *t, unsigned int state) |
| 770 | { |
| 771 | lockdep_assert_held(&t->sighand->siglock); |
| 772 | |
| 773 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
| 774 | |
| 775 | /* |
| 776 | * TASK_WAKEKILL also means wake it up in the stopped/traced/killable |
| 777 | * case. We don't check t->state here because there is a race with it |
| 778 | * executing another processor and just now entering stopped state. |
| 779 | * By using wake_up_state, we ensure the process will wake up and |
| 780 | * handle its death signal. |
| 781 | */ |
| 782 | if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) |
| 783 | kick_process(t); |
| 784 | } |
| 785 | |
| 786 | /* |
| 787 | * Remove signals in mask from the pending set and queue. |
| 788 | * Returns 1 if any signals were found. |
| 789 | * |
| 790 | * All callers must be holding the siglock. |
| 791 | */ |
| 792 | static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) |
| 793 | { |
| 794 | struct sigqueue *q, *n; |
| 795 | sigset_t m; |
| 796 | |
| 797 | sigandsets(&m, mask, &s->signal); |
| 798 | if (sigisemptyset(&m)) |
| 799 | return; |
| 800 | |
| 801 | sigandnsets(&s->signal, &s->signal, mask); |
| 802 | list_for_each_entry_safe(q, n, &s->list, list) { |
| 803 | if (sigismember(mask, q->info.si_signo)) { |
| 804 | list_del_init(&q->list); |
| 805 | __sigqueue_free(q); |
| 806 | } |
| 807 | } |
| 808 | } |
| 809 | |
| 810 | static inline int is_si_special(const struct kernel_siginfo *info) |
| 811 | { |
| 812 | return info <= SEND_SIG_PRIV; |
| 813 | } |
| 814 | |
| 815 | static inline bool si_fromuser(const struct kernel_siginfo *info) |
| 816 | { |
| 817 | return info == SEND_SIG_NOINFO || |
| 818 | (!is_si_special(info) && SI_FROMUSER(info)); |
| 819 | } |
| 820 | |
| 821 | /* |
| 822 | * called with RCU read lock from check_kill_permission() |
| 823 | */ |
| 824 | static bool kill_ok_by_cred(struct task_struct *t) |
| 825 | { |
| 826 | const struct cred *cred = current_cred(); |
| 827 | const struct cred *tcred = __task_cred(t); |
| 828 | |
| 829 | return uid_eq(cred->euid, tcred->suid) || |
| 830 | uid_eq(cred->euid, tcred->uid) || |
| 831 | uid_eq(cred->uid, tcred->suid) || |
| 832 | uid_eq(cred->uid, tcred->uid) || |
| 833 | ns_capable(tcred->user_ns, CAP_KILL); |
| 834 | } |
| 835 | |
| 836 | /* |
| 837 | * Bad permissions for sending the signal |
| 838 | * - the caller must hold the RCU read lock |
| 839 | */ |
| 840 | static int check_kill_permission(int sig, struct kernel_siginfo *info, |
| 841 | struct task_struct *t) |
| 842 | { |
| 843 | struct pid *sid; |
| 844 | int error; |
| 845 | |
| 846 | if (!valid_signal(sig)) |
| 847 | return -EINVAL; |
| 848 | |
| 849 | if (!si_fromuser(info)) |
| 850 | return 0; |
| 851 | |
| 852 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ |
| 853 | if (error) |
| 854 | return error; |
| 855 | |
| 856 | if (!same_thread_group(current, t) && |
| 857 | !kill_ok_by_cred(t)) { |
| 858 | switch (sig) { |
| 859 | case SIGCONT: |
| 860 | sid = task_session(t); |
| 861 | /* |
| 862 | * We don't return the error if sid == NULL. The |
| 863 | * task was unhashed, the caller must notice this. |
| 864 | */ |
| 865 | if (!sid || sid == task_session(current)) |
| 866 | break; |
| 867 | fallthrough; |
| 868 | default: |
| 869 | return -EPERM; |
| 870 | } |
| 871 | } |
| 872 | |
| 873 | return security_task_kill(t, info, sig, NULL); |
| 874 | } |
| 875 | |
| 876 | /** |
| 877 | * ptrace_trap_notify - schedule trap to notify ptracer |
| 878 | * @t: tracee wanting to notify tracer |
| 879 | * |
| 880 | * This function schedules sticky ptrace trap which is cleared on the next |
| 881 | * TRAP_STOP to notify ptracer of an event. @t must have been seized by |
| 882 | * ptracer. |
| 883 | * |
| 884 | * If @t is running, STOP trap will be taken. If trapped for STOP and |
| 885 | * ptracer is listening for events, tracee is woken up so that it can |
| 886 | * re-trap for the new event. If trapped otherwise, STOP trap will be |
| 887 | * eventually taken without returning to userland after the existing traps |
| 888 | * are finished by PTRACE_CONT. |
| 889 | * |
| 890 | * CONTEXT: |
| 891 | * Must be called with @task->sighand->siglock held. |
| 892 | */ |
| 893 | static void ptrace_trap_notify(struct task_struct *t) |
| 894 | { |
| 895 | WARN_ON_ONCE(!(t->ptrace & PT_SEIZED)); |
| 896 | lockdep_assert_held(&t->sighand->siglock); |
| 897 | |
| 898 | task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY); |
| 899 | ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING); |
| 900 | } |
| 901 | |
| 902 | /* |
| 903 | * Handle magic process-wide effects of stop/continue signals. Unlike |
| 904 | * the signal actions, these happen immediately at signal-generation |
| 905 | * time regardless of blocking, ignoring, or handling. This does the |
| 906 | * actual continuing for SIGCONT, but not the actual stopping for stop |
| 907 | * signals. The process stop is done as a signal action for SIG_DFL. |
| 908 | * |
| 909 | * Returns true if the signal should be actually delivered, otherwise |
| 910 | * it should be dropped. |
| 911 | */ |
| 912 | static bool prepare_signal(int sig, struct task_struct *p, bool force) |
| 913 | { |
| 914 | struct signal_struct *signal = p->signal; |
| 915 | struct task_struct *t; |
| 916 | sigset_t flush; |
| 917 | |
| 918 | if (signal->flags & SIGNAL_GROUP_EXIT) { |
| 919 | if (signal->core_state) |
| 920 | return sig == SIGKILL; |
| 921 | /* |
| 922 | * The process is in the middle of dying, drop the signal. |
| 923 | */ |
| 924 | return false; |
| 925 | } else if (sig_kernel_stop(sig)) { |
| 926 | /* |
| 927 | * This is a stop signal. Remove SIGCONT from all queues. |
| 928 | */ |
| 929 | siginitset(&flush, sigmask(SIGCONT)); |
| 930 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
| 931 | for_each_thread(p, t) |
| 932 | flush_sigqueue_mask(&flush, &t->pending); |
| 933 | } else if (sig == SIGCONT) { |
| 934 | unsigned int why; |
| 935 | /* |
| 936 | * Remove all stop signals from all queues, wake all threads. |
| 937 | */ |
| 938 | siginitset(&flush, SIG_KERNEL_STOP_MASK); |
| 939 | flush_sigqueue_mask(&flush, &signal->shared_pending); |
| 940 | for_each_thread(p, t) { |
| 941 | flush_sigqueue_mask(&flush, &t->pending); |
| 942 | task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); |
| 943 | if (likely(!(t->ptrace & PT_SEIZED))) { |
| 944 | t->jobctl &= ~JOBCTL_STOPPED; |
| 945 | wake_up_state(t, __TASK_STOPPED); |
| 946 | } else |
| 947 | ptrace_trap_notify(t); |
| 948 | } |
| 949 | |
| 950 | /* |
| 951 | * Notify the parent with CLD_CONTINUED if we were stopped. |
| 952 | * |
| 953 | * If we were in the middle of a group stop, we pretend it |
| 954 | * was already finished, and then continued. Since SIGCHLD |
| 955 | * doesn't queue we report only CLD_STOPPED, as if the next |
| 956 | * CLD_CONTINUED was dropped. |
| 957 | */ |
| 958 | why = 0; |
| 959 | if (signal->flags & SIGNAL_STOP_STOPPED) |
| 960 | why |= SIGNAL_CLD_CONTINUED; |
| 961 | else if (signal->group_stop_count) |
| 962 | why |= SIGNAL_CLD_STOPPED; |
| 963 | |
| 964 | if (why) { |
| 965 | /* |
| 966 | * The first thread which returns from do_signal_stop() |
| 967 | * will take ->siglock, notice SIGNAL_CLD_MASK, and |
| 968 | * notify its parent. See get_signal(). |
| 969 | */ |
| 970 | signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED); |
| 971 | signal->group_stop_count = 0; |
| 972 | signal->group_exit_code = 0; |
| 973 | } |
| 974 | } |
| 975 | |
| 976 | return !sig_ignored(p, sig, force); |
| 977 | } |
| 978 | |
| 979 | /* |
| 980 | * Test if P wants to take SIG. After we've checked all threads with this, |
| 981 | * it's equivalent to finding no threads not blocking SIG. Any threads not |
| 982 | * blocking SIG were ruled out because they are not running and already |
| 983 | * have pending signals. Such threads will dequeue from the shared queue |
| 984 | * as soon as they're available, so putting the signal on the shared queue |
| 985 | * will be equivalent to sending it to one such thread. |
| 986 | */ |
| 987 | static inline bool wants_signal(int sig, struct task_struct *p) |
| 988 | { |
| 989 | if (sigismember(&p->blocked, sig)) |
| 990 | return false; |
| 991 | |
| 992 | if (p->flags & PF_EXITING) |
| 993 | return false; |
| 994 | |
| 995 | if (sig == SIGKILL) |
| 996 | return true; |
| 997 | |
| 998 | if (task_is_stopped_or_traced(p)) |
| 999 | return false; |
| 1000 | |
| 1001 | return task_curr(p) || !task_sigpending(p); |
| 1002 | } |
| 1003 | |
| 1004 | static void complete_signal(int sig, struct task_struct *p, enum pid_type type) |
| 1005 | { |
| 1006 | struct signal_struct *signal = p->signal; |
| 1007 | struct task_struct *t; |
| 1008 | |
| 1009 | /* |
| 1010 | * Now find a thread we can wake up to take the signal off the queue. |
| 1011 | * |
| 1012 | * Try the suggested task first (may or may not be the main thread). |
| 1013 | */ |
| 1014 | if (wants_signal(sig, p)) |
| 1015 | t = p; |
| 1016 | else if ((type == PIDTYPE_PID) || thread_group_empty(p)) |
| 1017 | /* |
| 1018 | * There is just one thread and it does not need to be woken. |
| 1019 | * It will dequeue unblocked signals before it runs again. |
| 1020 | */ |
| 1021 | return; |
| 1022 | else { |
| 1023 | /* |
| 1024 | * Otherwise try to find a suitable thread. |
| 1025 | */ |
| 1026 | t = signal->curr_target; |
| 1027 | while (!wants_signal(sig, t)) { |
| 1028 | t = next_thread(t); |
| 1029 | if (t == signal->curr_target) |
| 1030 | /* |
| 1031 | * No thread needs to be woken. |
| 1032 | * Any eligible threads will see |
| 1033 | * the signal in the queue soon. |
| 1034 | */ |
| 1035 | return; |
| 1036 | } |
| 1037 | signal->curr_target = t; |
| 1038 | } |
| 1039 | |
| 1040 | /* |
| 1041 | * Found a killable thread. If the signal will be fatal, |
| 1042 | * then start taking the whole group down immediately. |
| 1043 | */ |
| 1044 | if (sig_fatal(p, sig) && |
| 1045 | (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) && |
| 1046 | !sigismember(&t->real_blocked, sig) && |
| 1047 | (sig == SIGKILL || !p->ptrace)) { |
| 1048 | /* |
| 1049 | * This signal will be fatal to the whole group. |
| 1050 | */ |
| 1051 | if (!sig_kernel_coredump(sig)) { |
| 1052 | /* |
| 1053 | * Start a group exit and wake everybody up. |
| 1054 | * This way we don't have other threads |
| 1055 | * running and doing things after a slower |
| 1056 | * thread has the fatal signal pending. |
| 1057 | */ |
| 1058 | signal->flags = SIGNAL_GROUP_EXIT; |
| 1059 | signal->group_exit_code = sig; |
| 1060 | signal->group_stop_count = 0; |
| 1061 | __for_each_thread(signal, t) { |
| 1062 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
| 1063 | sigaddset(&t->pending.signal, SIGKILL); |
| 1064 | signal_wake_up(t, 1); |
| 1065 | } |
| 1066 | return; |
| 1067 | } |
| 1068 | } |
| 1069 | |
| 1070 | /* |
| 1071 | * The signal is already in the shared-pending queue. |
| 1072 | * Tell the chosen thread to wake up and dequeue it. |
| 1073 | */ |
| 1074 | signal_wake_up(t, sig == SIGKILL); |
| 1075 | return; |
| 1076 | } |
| 1077 | |
| 1078 | static inline bool legacy_queue(struct sigpending *signals, int sig) |
| 1079 | { |
| 1080 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); |
| 1081 | } |
| 1082 | |
| 1083 | static int __send_signal_locked(int sig, struct kernel_siginfo *info, |
| 1084 | struct task_struct *t, enum pid_type type, bool force) |
| 1085 | { |
| 1086 | struct sigpending *pending; |
| 1087 | struct sigqueue *q; |
| 1088 | int override_rlimit; |
| 1089 | int ret = 0, result; |
| 1090 | |
| 1091 | lockdep_assert_held(&t->sighand->siglock); |
| 1092 | |
| 1093 | result = TRACE_SIGNAL_IGNORED; |
| 1094 | if (!prepare_signal(sig, t, force)) |
| 1095 | goto ret; |
| 1096 | |
| 1097 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
| 1098 | /* |
| 1099 | * Short-circuit ignored signals and support queuing |
| 1100 | * exactly one non-rt signal, so that we can get more |
| 1101 | * detailed information about the cause of the signal. |
| 1102 | */ |
| 1103 | result = TRACE_SIGNAL_ALREADY_PENDING; |
| 1104 | if (legacy_queue(pending, sig)) |
| 1105 | goto ret; |
| 1106 | |
| 1107 | result = TRACE_SIGNAL_DELIVERED; |
| 1108 | /* |
| 1109 | * Skip useless siginfo allocation for SIGKILL and kernel threads. |
| 1110 | */ |
| 1111 | if ((sig == SIGKILL) || (t->flags & PF_KTHREAD)) |
| 1112 | goto out_set; |
| 1113 | |
| 1114 | /* |
| 1115 | * Real-time signals must be queued if sent by sigqueue, or |
| 1116 | * some other real-time mechanism. It is implementation |
| 1117 | * defined whether kill() does so. We attempt to do so, on |
| 1118 | * the principle of least surprise, but since kill is not |
| 1119 | * allowed to fail with EAGAIN when low on memory we just |
| 1120 | * make sure at least one signal gets delivered and don't |
| 1121 | * pass on the info struct. |
| 1122 | */ |
| 1123 | if (sig < SIGRTMIN) |
| 1124 | override_rlimit = (is_si_special(info) || info->si_code >= 0); |
| 1125 | else |
| 1126 | override_rlimit = 0; |
| 1127 | |
| 1128 | q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0); |
| 1129 | |
| 1130 | if (q) { |
| 1131 | list_add_tail(&q->list, &pending->list); |
| 1132 | switch ((unsigned long) info) { |
| 1133 | case (unsigned long) SEND_SIG_NOINFO: |
| 1134 | clear_siginfo(&q->info); |
| 1135 | q->info.si_signo = sig; |
| 1136 | q->info.si_errno = 0; |
| 1137 | q->info.si_code = SI_USER; |
| 1138 | q->info.si_pid = task_tgid_nr_ns(current, |
| 1139 | task_active_pid_ns(t)); |
| 1140 | rcu_read_lock(); |
| 1141 | q->info.si_uid = |
| 1142 | from_kuid_munged(task_cred_xxx(t, user_ns), |
| 1143 | current_uid()); |
| 1144 | rcu_read_unlock(); |
| 1145 | break; |
| 1146 | case (unsigned long) SEND_SIG_PRIV: |
| 1147 | clear_siginfo(&q->info); |
| 1148 | q->info.si_signo = sig; |
| 1149 | q->info.si_errno = 0; |
| 1150 | q->info.si_code = SI_KERNEL; |
| 1151 | q->info.si_pid = 0; |
| 1152 | q->info.si_uid = 0; |
| 1153 | break; |
| 1154 | default: |
| 1155 | copy_siginfo(&q->info, info); |
| 1156 | break; |
| 1157 | } |
| 1158 | } else if (!is_si_special(info) && |
| 1159 | sig >= SIGRTMIN && info->si_code != SI_USER) { |
| 1160 | /* |
| 1161 | * Queue overflow, abort. We may abort if the |
| 1162 | * signal was rt and sent by user using something |
| 1163 | * other than kill(). |
| 1164 | */ |
| 1165 | result = TRACE_SIGNAL_OVERFLOW_FAIL; |
| 1166 | ret = -EAGAIN; |
| 1167 | goto ret; |
| 1168 | } else { |
| 1169 | /* |
| 1170 | * This is a silent loss of information. We still |
| 1171 | * send the signal, but the *info bits are lost. |
| 1172 | */ |
| 1173 | result = TRACE_SIGNAL_LOSE_INFO; |
| 1174 | } |
| 1175 | |
| 1176 | out_set: |
| 1177 | signalfd_notify(t, sig); |
| 1178 | sigaddset(&pending->signal, sig); |
| 1179 | |
| 1180 | /* Let multiprocess signals appear after on-going forks */ |
| 1181 | if (type > PIDTYPE_TGID) { |
| 1182 | struct multiprocess_signals *delayed; |
| 1183 | hlist_for_each_entry(delayed, &t->signal->multiprocess, node) { |
| 1184 | sigset_t *signal = &delayed->signal; |
| 1185 | /* Can't queue both a stop and a continue signal */ |
| 1186 | if (sig == SIGCONT) |
| 1187 | sigdelsetmask(signal, SIG_KERNEL_STOP_MASK); |
| 1188 | else if (sig_kernel_stop(sig)) |
| 1189 | sigdelset(signal, SIGCONT); |
| 1190 | sigaddset(signal, sig); |
| 1191 | } |
| 1192 | } |
| 1193 | |
| 1194 | complete_signal(sig, t, type); |
| 1195 | ret: |
| 1196 | trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result); |
| 1197 | return ret; |
| 1198 | } |
| 1199 | |
| 1200 | static inline bool has_si_pid_and_uid(struct kernel_siginfo *info) |
| 1201 | { |
| 1202 | bool ret = false; |
| 1203 | switch (siginfo_layout(info->si_signo, info->si_code)) { |
| 1204 | case SIL_KILL: |
| 1205 | case SIL_CHLD: |
| 1206 | case SIL_RT: |
| 1207 | ret = true; |
| 1208 | break; |
| 1209 | case SIL_TIMER: |
| 1210 | case SIL_POLL: |
| 1211 | case SIL_FAULT: |
| 1212 | case SIL_FAULT_TRAPNO: |
| 1213 | case SIL_FAULT_MCEERR: |
| 1214 | case SIL_FAULT_BNDERR: |
| 1215 | case SIL_FAULT_PKUERR: |
| 1216 | case SIL_FAULT_PERF_EVENT: |
| 1217 | case SIL_SYS: |
| 1218 | ret = false; |
| 1219 | break; |
| 1220 | } |
| 1221 | return ret; |
| 1222 | } |
| 1223 | |
| 1224 | int send_signal_locked(int sig, struct kernel_siginfo *info, |
| 1225 | struct task_struct *t, enum pid_type type) |
| 1226 | { |
| 1227 | /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */ |
| 1228 | bool force = false; |
| 1229 | |
| 1230 | if (info == SEND_SIG_NOINFO) { |
| 1231 | /* Force if sent from an ancestor pid namespace */ |
| 1232 | force = !task_pid_nr_ns(current, task_active_pid_ns(t)); |
| 1233 | } else if (info == SEND_SIG_PRIV) { |
| 1234 | /* Don't ignore kernel generated signals */ |
| 1235 | force = true; |
| 1236 | } else if (has_si_pid_and_uid(info)) { |
| 1237 | /* SIGKILL and SIGSTOP is special or has ids */ |
| 1238 | struct user_namespace *t_user_ns; |
| 1239 | |
| 1240 | rcu_read_lock(); |
| 1241 | t_user_ns = task_cred_xxx(t, user_ns); |
| 1242 | if (current_user_ns() != t_user_ns) { |
| 1243 | kuid_t uid = make_kuid(current_user_ns(), info->si_uid); |
| 1244 | info->si_uid = from_kuid_munged(t_user_ns, uid); |
| 1245 | } |
| 1246 | rcu_read_unlock(); |
| 1247 | |
| 1248 | /* A kernel generated signal? */ |
| 1249 | force = (info->si_code == SI_KERNEL); |
| 1250 | |
| 1251 | /* From an ancestor pid namespace? */ |
| 1252 | if (!task_pid_nr_ns(current, task_active_pid_ns(t))) { |
| 1253 | info->si_pid = 0; |
| 1254 | force = true; |
| 1255 | } |
| 1256 | } |
| 1257 | return __send_signal_locked(sig, info, t, type, force); |
| 1258 | } |
| 1259 | |
| 1260 | static void print_fatal_signal(int signr) |
| 1261 | { |
| 1262 | struct pt_regs *regs = task_pt_regs(current); |
| 1263 | struct file *exe_file; |
| 1264 | |
| 1265 | exe_file = get_task_exe_file(current); |
| 1266 | if (exe_file) { |
| 1267 | pr_info("%pD: %s: potentially unexpected fatal signal %d.\n", |
| 1268 | exe_file, current->comm, signr); |
| 1269 | fput(exe_file); |
| 1270 | } else { |
| 1271 | pr_info("%s: potentially unexpected fatal signal %d.\n", |
| 1272 | current->comm, signr); |
| 1273 | } |
| 1274 | |
| 1275 | #if defined(__i386__) && !defined(__arch_um__) |
| 1276 | pr_info("code at %08lx: ", regs->ip); |
| 1277 | { |
| 1278 | int i; |
| 1279 | for (i = 0; i < 16; i++) { |
| 1280 | unsigned char insn; |
| 1281 | |
| 1282 | if (get_user(insn, (unsigned char *)(regs->ip + i))) |
| 1283 | break; |
| 1284 | pr_cont("%02x ", insn); |
| 1285 | } |
| 1286 | } |
| 1287 | pr_cont("\n"); |
| 1288 | #endif |
| 1289 | preempt_disable(); |
| 1290 | show_regs(regs); |
| 1291 | preempt_enable(); |
| 1292 | } |
| 1293 | |
| 1294 | static int __init setup_print_fatal_signals(char *str) |
| 1295 | { |
| 1296 | get_option (&str, &print_fatal_signals); |
| 1297 | |
| 1298 | return 1; |
| 1299 | } |
| 1300 | |
| 1301 | __setup("print-fatal-signals=", setup_print_fatal_signals); |
| 1302 | |
| 1303 | int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, |
| 1304 | enum pid_type type) |
| 1305 | { |
| 1306 | unsigned long flags; |
| 1307 | int ret = -ESRCH; |
| 1308 | |
| 1309 | if (lock_task_sighand(p, &flags)) { |
| 1310 | ret = send_signal_locked(sig, info, p, type); |
| 1311 | unlock_task_sighand(p, &flags); |
| 1312 | } |
| 1313 | |
| 1314 | return ret; |
| 1315 | } |
| 1316 | |
| 1317 | enum sig_handler { |
| 1318 | HANDLER_CURRENT, /* If reachable use the current handler */ |
| 1319 | HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */ |
| 1320 | HANDLER_EXIT, /* Only visible as the process exit code */ |
| 1321 | }; |
| 1322 | |
| 1323 | /* |
| 1324 | * Force a signal that the process can't ignore: if necessary |
| 1325 | * we unblock the signal and change any SIG_IGN to SIG_DFL. |
| 1326 | * |
| 1327 | * Note: If we unblock the signal, we always reset it to SIG_DFL, |
| 1328 | * since we do not want to have a signal handler that was blocked |
| 1329 | * be invoked when user space had explicitly blocked it. |
| 1330 | * |
| 1331 | * We don't want to have recursive SIGSEGV's etc, for example, |
| 1332 | * that is why we also clear SIGNAL_UNKILLABLE. |
| 1333 | */ |
| 1334 | static int |
| 1335 | force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t, |
| 1336 | enum sig_handler handler) |
| 1337 | { |
| 1338 | unsigned long int flags; |
| 1339 | int ret, blocked, ignored; |
| 1340 | struct k_sigaction *action; |
| 1341 | int sig = info->si_signo; |
| 1342 | |
| 1343 | spin_lock_irqsave(&t->sighand->siglock, flags); |
| 1344 | action = &t->sighand->action[sig-1]; |
| 1345 | ignored = action->sa.sa_handler == SIG_IGN; |
| 1346 | blocked = sigismember(&t->blocked, sig); |
| 1347 | if (blocked || ignored || (handler != HANDLER_CURRENT)) { |
| 1348 | action->sa.sa_handler = SIG_DFL; |
| 1349 | if (handler == HANDLER_EXIT) |
| 1350 | action->sa.sa_flags |= SA_IMMUTABLE; |
| 1351 | if (blocked) { |
| 1352 | sigdelset(&t->blocked, sig); |
| 1353 | recalc_sigpending_and_wake(t); |
| 1354 | } |
| 1355 | } |
| 1356 | /* |
| 1357 | * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect |
| 1358 | * debugging to leave init killable. But HANDLER_EXIT is always fatal. |
| 1359 | */ |
| 1360 | if (action->sa.sa_handler == SIG_DFL && |
| 1361 | (!t->ptrace || (handler == HANDLER_EXIT))) |
| 1362 | t->signal->flags &= ~SIGNAL_UNKILLABLE; |
| 1363 | ret = send_signal_locked(sig, info, t, PIDTYPE_PID); |
| 1364 | spin_unlock_irqrestore(&t->sighand->siglock, flags); |
| 1365 | |
| 1366 | return ret; |
| 1367 | } |
| 1368 | |
| 1369 | int force_sig_info(struct kernel_siginfo *info) |
| 1370 | { |
| 1371 | return force_sig_info_to_task(info, current, HANDLER_CURRENT); |
| 1372 | } |
| 1373 | |
| 1374 | /* |
| 1375 | * Nuke all other threads in the group. |
| 1376 | */ |
| 1377 | int zap_other_threads(struct task_struct *p) |
| 1378 | { |
| 1379 | struct task_struct *t = p; |
| 1380 | int count = 0; |
| 1381 | |
| 1382 | p->signal->group_stop_count = 0; |
| 1383 | |
| 1384 | while_each_thread(p, t) { |
| 1385 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
| 1386 | /* Don't require de_thread to wait for the vhost_worker */ |
| 1387 | if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER) |
| 1388 | count++; |
| 1389 | |
| 1390 | /* Don't bother with already dead threads */ |
| 1391 | if (t->exit_state) |
| 1392 | continue; |
| 1393 | sigaddset(&t->pending.signal, SIGKILL); |
| 1394 | signal_wake_up(t, 1); |
| 1395 | } |
| 1396 | |
| 1397 | return count; |
| 1398 | } |
| 1399 | |
| 1400 | struct sighand_struct *__lock_task_sighand(struct task_struct *tsk, |
| 1401 | unsigned long *flags) |
| 1402 | { |
| 1403 | struct sighand_struct *sighand; |
| 1404 | |
| 1405 | rcu_read_lock(); |
| 1406 | for (;;) { |
| 1407 | sighand = rcu_dereference(tsk->sighand); |
| 1408 | if (unlikely(sighand == NULL)) |
| 1409 | break; |
| 1410 | |
| 1411 | /* |
| 1412 | * This sighand can be already freed and even reused, but |
| 1413 | * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which |
| 1414 | * initializes ->siglock: this slab can't go away, it has |
| 1415 | * the same object type, ->siglock can't be reinitialized. |
| 1416 | * |
| 1417 | * We need to ensure that tsk->sighand is still the same |
| 1418 | * after we take the lock, we can race with de_thread() or |
| 1419 | * __exit_signal(). In the latter case the next iteration |
| 1420 | * must see ->sighand == NULL. |
| 1421 | */ |
| 1422 | spin_lock_irqsave(&sighand->siglock, *flags); |
| 1423 | if (likely(sighand == rcu_access_pointer(tsk->sighand))) |
| 1424 | break; |
| 1425 | spin_unlock_irqrestore(&sighand->siglock, *flags); |
| 1426 | } |
| 1427 | rcu_read_unlock(); |
| 1428 | |
| 1429 | return sighand; |
| 1430 | } |
| 1431 | |
| 1432 | #ifdef CONFIG_LOCKDEP |
| 1433 | void lockdep_assert_task_sighand_held(struct task_struct *task) |
| 1434 | { |
| 1435 | struct sighand_struct *sighand; |
| 1436 | |
| 1437 | rcu_read_lock(); |
| 1438 | sighand = rcu_dereference(task->sighand); |
| 1439 | if (sighand) |
| 1440 | lockdep_assert_held(&sighand->siglock); |
| 1441 | else |
| 1442 | WARN_ON_ONCE(1); |
| 1443 | rcu_read_unlock(); |
| 1444 | } |
| 1445 | #endif |
| 1446 | |
| 1447 | /* |
| 1448 | * send signal info to all the members of a group |
| 1449 | */ |
| 1450 | int group_send_sig_info(int sig, struct kernel_siginfo *info, |
| 1451 | struct task_struct *p, enum pid_type type) |
| 1452 | { |
| 1453 | int ret; |
| 1454 | |
| 1455 | rcu_read_lock(); |
| 1456 | ret = check_kill_permission(sig, info, p); |
| 1457 | rcu_read_unlock(); |
| 1458 | |
| 1459 | if (!ret && sig) |
| 1460 | ret = do_send_sig_info(sig, info, p, type); |
| 1461 | |
| 1462 | return ret; |
| 1463 | } |
| 1464 | |
| 1465 | /* |
| 1466 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
| 1467 | * control characters do (^C, ^Z etc) |
| 1468 | * - the caller must hold at least a readlock on tasklist_lock |
| 1469 | */ |
| 1470 | int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) |
| 1471 | { |
| 1472 | struct task_struct *p = NULL; |
| 1473 | int ret = -ESRCH; |
| 1474 | |
| 1475 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
| 1476 | int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID); |
| 1477 | /* |
| 1478 | * If group_send_sig_info() succeeds at least once ret |
| 1479 | * becomes 0 and after that the code below has no effect. |
| 1480 | * Otherwise we return the last err or -ESRCH if this |
| 1481 | * process group is empty. |
| 1482 | */ |
| 1483 | if (ret) |
| 1484 | ret = err; |
| 1485 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
| 1486 | |
| 1487 | return ret; |
| 1488 | } |
| 1489 | |
| 1490 | int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) |
| 1491 | { |
| 1492 | int error = -ESRCH; |
| 1493 | struct task_struct *p; |
| 1494 | |
| 1495 | for (;;) { |
| 1496 | rcu_read_lock(); |
| 1497 | p = pid_task(pid, PIDTYPE_PID); |
| 1498 | if (p) |
| 1499 | error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); |
| 1500 | rcu_read_unlock(); |
| 1501 | if (likely(!p || error != -ESRCH)) |
| 1502 | return error; |
| 1503 | |
| 1504 | /* |
| 1505 | * The task was unhashed in between, try again. If it |
| 1506 | * is dead, pid_task() will return NULL, if we race with |
| 1507 | * de_thread() it will find the new leader. |
| 1508 | */ |
| 1509 | } |
| 1510 | } |
| 1511 | |
| 1512 | static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) |
| 1513 | { |
| 1514 | int error; |
| 1515 | rcu_read_lock(); |
| 1516 | error = kill_pid_info(sig, info, find_vpid(pid)); |
| 1517 | rcu_read_unlock(); |
| 1518 | return error; |
| 1519 | } |
| 1520 | |
| 1521 | static inline bool kill_as_cred_perm(const struct cred *cred, |
| 1522 | struct task_struct *target) |
| 1523 | { |
| 1524 | const struct cred *pcred = __task_cred(target); |
| 1525 | |
| 1526 | return uid_eq(cred->euid, pcred->suid) || |
| 1527 | uid_eq(cred->euid, pcred->uid) || |
| 1528 | uid_eq(cred->uid, pcred->suid) || |
| 1529 | uid_eq(cred->uid, pcred->uid); |
| 1530 | } |
| 1531 | |
| 1532 | /* |
| 1533 | * The usb asyncio usage of siginfo is wrong. The glibc support |
| 1534 | * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT. |
| 1535 | * AKA after the generic fields: |
| 1536 | * kernel_pid_t si_pid; |
| 1537 | * kernel_uid32_t si_uid; |
| 1538 | * sigval_t si_value; |
| 1539 | * |
| 1540 | * Unfortunately when usb generates SI_ASYNCIO it assumes the layout |
| 1541 | * after the generic fields is: |
| 1542 | * void __user *si_addr; |
| 1543 | * |
| 1544 | * This is a practical problem when there is a 64bit big endian kernel |
| 1545 | * and a 32bit userspace. As the 32bit address will encoded in the low |
| 1546 | * 32bits of the pointer. Those low 32bits will be stored at higher |
| 1547 | * address than appear in a 32 bit pointer. So userspace will not |
| 1548 | * see the address it was expecting for it's completions. |
| 1549 | * |
| 1550 | * There is nothing in the encoding that can allow |
| 1551 | * copy_siginfo_to_user32 to detect this confusion of formats, so |
| 1552 | * handle this by requiring the caller of kill_pid_usb_asyncio to |
| 1553 | * notice when this situration takes place and to store the 32bit |
| 1554 | * pointer in sival_int, instead of sival_addr of the sigval_t addr |
| 1555 | * parameter. |
| 1556 | */ |
| 1557 | int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, |
| 1558 | struct pid *pid, const struct cred *cred) |
| 1559 | { |
| 1560 | struct kernel_siginfo info; |
| 1561 | struct task_struct *p; |
| 1562 | unsigned long flags; |
| 1563 | int ret = -EINVAL; |
| 1564 | |
| 1565 | if (!valid_signal(sig)) |
| 1566 | return ret; |
| 1567 | |
| 1568 | clear_siginfo(&info); |
| 1569 | info.si_signo = sig; |
| 1570 | info.si_errno = errno; |
| 1571 | info.si_code = SI_ASYNCIO; |
| 1572 | *((sigval_t *)&info.si_pid) = addr; |
| 1573 | |
| 1574 | rcu_read_lock(); |
| 1575 | p = pid_task(pid, PIDTYPE_PID); |
| 1576 | if (!p) { |
| 1577 | ret = -ESRCH; |
| 1578 | goto out_unlock; |
| 1579 | } |
| 1580 | if (!kill_as_cred_perm(cred, p)) { |
| 1581 | ret = -EPERM; |
| 1582 | goto out_unlock; |
| 1583 | } |
| 1584 | ret = security_task_kill(p, &info, sig, cred); |
| 1585 | if (ret) |
| 1586 | goto out_unlock; |
| 1587 | |
| 1588 | if (sig) { |
| 1589 | if (lock_task_sighand(p, &flags)) { |
| 1590 | ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false); |
| 1591 | unlock_task_sighand(p, &flags); |
| 1592 | } else |
| 1593 | ret = -ESRCH; |
| 1594 | } |
| 1595 | out_unlock: |
| 1596 | rcu_read_unlock(); |
| 1597 | return ret; |
| 1598 | } |
| 1599 | EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio); |
| 1600 | |
| 1601 | /* |
| 1602 | * kill_something_info() interprets pid in interesting ways just like kill(2). |
| 1603 | * |
| 1604 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have |
| 1605 | * is probably wrong. Should make it like BSD or SYSV. |
| 1606 | */ |
| 1607 | |
| 1608 | static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid) |
| 1609 | { |
| 1610 | int ret; |
| 1611 | |
| 1612 | if (pid > 0) |
| 1613 | return kill_proc_info(sig, info, pid); |
| 1614 | |
| 1615 | /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ |
| 1616 | if (pid == INT_MIN) |
| 1617 | return -ESRCH; |
| 1618 | |
| 1619 | read_lock(&tasklist_lock); |
| 1620 | if (pid != -1) { |
| 1621 | ret = __kill_pgrp_info(sig, info, |
| 1622 | pid ? find_vpid(-pid) : task_pgrp(current)); |
| 1623 | } else { |
| 1624 | int retval = 0, count = 0; |
| 1625 | struct task_struct * p; |
| 1626 | |
| 1627 | for_each_process(p) { |
| 1628 | if (task_pid_vnr(p) > 1 && |
| 1629 | !same_thread_group(p, current)) { |
| 1630 | int err = group_send_sig_info(sig, info, p, |
| 1631 | PIDTYPE_MAX); |
| 1632 | ++count; |
| 1633 | if (err != -EPERM) |
| 1634 | retval = err; |
| 1635 | } |
| 1636 | } |
| 1637 | ret = count ? retval : -ESRCH; |
| 1638 | } |
| 1639 | read_unlock(&tasklist_lock); |
| 1640 | |
| 1641 | return ret; |
| 1642 | } |
| 1643 | |
| 1644 | /* |
| 1645 | * These are for backward compatibility with the rest of the kernel source. |
| 1646 | */ |
| 1647 | |
| 1648 | int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p) |
| 1649 | { |
| 1650 | /* |
| 1651 | * Make sure legacy kernel users don't send in bad values |
| 1652 | * (normal paths check this in check_kill_permission). |
| 1653 | */ |
| 1654 | if (!valid_signal(sig)) |
| 1655 | return -EINVAL; |
| 1656 | |
| 1657 | return do_send_sig_info(sig, info, p, PIDTYPE_PID); |
| 1658 | } |
| 1659 | EXPORT_SYMBOL(send_sig_info); |
| 1660 | |
| 1661 | #define __si_special(priv) \ |
| 1662 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) |
| 1663 | |
| 1664 | int |
| 1665 | send_sig(int sig, struct task_struct *p, int priv) |
| 1666 | { |
| 1667 | return send_sig_info(sig, __si_special(priv), p); |
| 1668 | } |
| 1669 | EXPORT_SYMBOL(send_sig); |
| 1670 | |
| 1671 | void force_sig(int sig) |
| 1672 | { |
| 1673 | struct kernel_siginfo info; |
| 1674 | |
| 1675 | clear_siginfo(&info); |
| 1676 | info.si_signo = sig; |
| 1677 | info.si_errno = 0; |
| 1678 | info.si_code = SI_KERNEL; |
| 1679 | info.si_pid = 0; |
| 1680 | info.si_uid = 0; |
| 1681 | force_sig_info(&info); |
| 1682 | } |
| 1683 | EXPORT_SYMBOL(force_sig); |
| 1684 | |
| 1685 | void force_fatal_sig(int sig) |
| 1686 | { |
| 1687 | struct kernel_siginfo info; |
| 1688 | |
| 1689 | clear_siginfo(&info); |
| 1690 | info.si_signo = sig; |
| 1691 | info.si_errno = 0; |
| 1692 | info.si_code = SI_KERNEL; |
| 1693 | info.si_pid = 0; |
| 1694 | info.si_uid = 0; |
| 1695 | force_sig_info_to_task(&info, current, HANDLER_SIG_DFL); |
| 1696 | } |
| 1697 | |
| 1698 | void force_exit_sig(int sig) |
| 1699 | { |
| 1700 | struct kernel_siginfo info; |
| 1701 | |
| 1702 | clear_siginfo(&info); |
| 1703 | info.si_signo = sig; |
| 1704 | info.si_errno = 0; |
| 1705 | info.si_code = SI_KERNEL; |
| 1706 | info.si_pid = 0; |
| 1707 | info.si_uid = 0; |
| 1708 | force_sig_info_to_task(&info, current, HANDLER_EXIT); |
| 1709 | } |
| 1710 | |
| 1711 | /* |
| 1712 | * When things go south during signal handling, we |
| 1713 | * will force a SIGSEGV. And if the signal that caused |
| 1714 | * the problem was already a SIGSEGV, we'll want to |
| 1715 | * make sure we don't even try to deliver the signal.. |
| 1716 | */ |
| 1717 | void force_sigsegv(int sig) |
| 1718 | { |
| 1719 | if (sig == SIGSEGV) |
| 1720 | force_fatal_sig(SIGSEGV); |
| 1721 | else |
| 1722 | force_sig(SIGSEGV); |
| 1723 | } |
| 1724 | |
| 1725 | int force_sig_fault_to_task(int sig, int code, void __user *addr, |
| 1726 | struct task_struct *t) |
| 1727 | { |
| 1728 | struct kernel_siginfo info; |
| 1729 | |
| 1730 | clear_siginfo(&info); |
| 1731 | info.si_signo = sig; |
| 1732 | info.si_errno = 0; |
| 1733 | info.si_code = code; |
| 1734 | info.si_addr = addr; |
| 1735 | return force_sig_info_to_task(&info, t, HANDLER_CURRENT); |
| 1736 | } |
| 1737 | |
| 1738 | int force_sig_fault(int sig, int code, void __user *addr) |
| 1739 | { |
| 1740 | return force_sig_fault_to_task(sig, code, addr, current); |
| 1741 | } |
| 1742 | |
| 1743 | int send_sig_fault(int sig, int code, void __user *addr, struct task_struct *t) |
| 1744 | { |
| 1745 | struct kernel_siginfo info; |
| 1746 | |
| 1747 | clear_siginfo(&info); |
| 1748 | info.si_signo = sig; |
| 1749 | info.si_errno = 0; |
| 1750 | info.si_code = code; |
| 1751 | info.si_addr = addr; |
| 1752 | return send_sig_info(info.si_signo, &info, t); |
| 1753 | } |
| 1754 | |
| 1755 | int force_sig_mceerr(int code, void __user *addr, short lsb) |
| 1756 | { |
| 1757 | struct kernel_siginfo info; |
| 1758 | |
| 1759 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); |
| 1760 | clear_siginfo(&info); |
| 1761 | info.si_signo = SIGBUS; |
| 1762 | info.si_errno = 0; |
| 1763 | info.si_code = code; |
| 1764 | info.si_addr = addr; |
| 1765 | info.si_addr_lsb = lsb; |
| 1766 | return force_sig_info(&info); |
| 1767 | } |
| 1768 | |
| 1769 | int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t) |
| 1770 | { |
| 1771 | struct kernel_siginfo info; |
| 1772 | |
| 1773 | WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR)); |
| 1774 | clear_siginfo(&info); |
| 1775 | info.si_signo = SIGBUS; |
| 1776 | info.si_errno = 0; |
| 1777 | info.si_code = code; |
| 1778 | info.si_addr = addr; |
| 1779 | info.si_addr_lsb = lsb; |
| 1780 | return send_sig_info(info.si_signo, &info, t); |
| 1781 | } |
| 1782 | EXPORT_SYMBOL(send_sig_mceerr); |
| 1783 | |
| 1784 | int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper) |
| 1785 | { |
| 1786 | struct kernel_siginfo info; |
| 1787 | |
| 1788 | clear_siginfo(&info); |
| 1789 | info.si_signo = SIGSEGV; |
| 1790 | info.si_errno = 0; |
| 1791 | info.si_code = SEGV_BNDERR; |
| 1792 | info.si_addr = addr; |
| 1793 | info.si_lower = lower; |
| 1794 | info.si_upper = upper; |
| 1795 | return force_sig_info(&info); |
| 1796 | } |
| 1797 | |
| 1798 | #ifdef SEGV_PKUERR |
| 1799 | int force_sig_pkuerr(void __user *addr, u32 pkey) |
| 1800 | { |
| 1801 | struct kernel_siginfo info; |
| 1802 | |
| 1803 | clear_siginfo(&info); |
| 1804 | info.si_signo = SIGSEGV; |
| 1805 | info.si_errno = 0; |
| 1806 | info.si_code = SEGV_PKUERR; |
| 1807 | info.si_addr = addr; |
| 1808 | info.si_pkey = pkey; |
| 1809 | return force_sig_info(&info); |
| 1810 | } |
| 1811 | #endif |
| 1812 | |
| 1813 | int send_sig_perf(void __user *addr, u32 type, u64 sig_data) |
| 1814 | { |
| 1815 | struct kernel_siginfo info; |
| 1816 | |
| 1817 | clear_siginfo(&info); |
| 1818 | info.si_signo = SIGTRAP; |
| 1819 | info.si_errno = 0; |
| 1820 | info.si_code = TRAP_PERF; |
| 1821 | info.si_addr = addr; |
| 1822 | info.si_perf_data = sig_data; |
| 1823 | info.si_perf_type = type; |
| 1824 | |
| 1825 | /* |
| 1826 | * Signals generated by perf events should not terminate the whole |
| 1827 | * process if SIGTRAP is blocked, however, delivering the signal |
| 1828 | * asynchronously is better than not delivering at all. But tell user |
| 1829 | * space if the signal was asynchronous, so it can clearly be |
| 1830 | * distinguished from normal synchronous ones. |
| 1831 | */ |
| 1832 | info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ? |
| 1833 | TRAP_PERF_FLAG_ASYNC : |
| 1834 | 0; |
| 1835 | |
| 1836 | return send_sig_info(info.si_signo, &info, current); |
| 1837 | } |
| 1838 | |
| 1839 | /** |
| 1840 | * force_sig_seccomp - signals the task to allow in-process syscall emulation |
| 1841 | * @syscall: syscall number to send to userland |
| 1842 | * @reason: filter-supplied reason code to send to userland (via si_errno) |
| 1843 | * @force_coredump: true to trigger a coredump |
| 1844 | * |
| 1845 | * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info. |
| 1846 | */ |
| 1847 | int force_sig_seccomp(int syscall, int reason, bool force_coredump) |
| 1848 | { |
| 1849 | struct kernel_siginfo info; |
| 1850 | |
| 1851 | clear_siginfo(&info); |
| 1852 | info.si_signo = SIGSYS; |
| 1853 | info.si_code = SYS_SECCOMP; |
| 1854 | info.si_call_addr = (void __user *)KSTK_EIP(current); |
| 1855 | info.si_errno = reason; |
| 1856 | info.si_arch = syscall_get_arch(current); |
| 1857 | info.si_syscall = syscall; |
| 1858 | return force_sig_info_to_task(&info, current, |
| 1859 | force_coredump ? HANDLER_EXIT : HANDLER_CURRENT); |
| 1860 | } |
| 1861 | |
| 1862 | /* For the crazy architectures that include trap information in |
| 1863 | * the errno field, instead of an actual errno value. |
| 1864 | */ |
| 1865 | int force_sig_ptrace_errno_trap(int errno, void __user *addr) |
| 1866 | { |
| 1867 | struct kernel_siginfo info; |
| 1868 | |
| 1869 | clear_siginfo(&info); |
| 1870 | info.si_signo = SIGTRAP; |
| 1871 | info.si_errno = errno; |
| 1872 | info.si_code = TRAP_HWBKPT; |
| 1873 | info.si_addr = addr; |
| 1874 | return force_sig_info(&info); |
| 1875 | } |
| 1876 | |
| 1877 | /* For the rare architectures that include trap information using |
| 1878 | * si_trapno. |
| 1879 | */ |
| 1880 | int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno) |
| 1881 | { |
| 1882 | struct kernel_siginfo info; |
| 1883 | |
| 1884 | clear_siginfo(&info); |
| 1885 | info.si_signo = sig; |
| 1886 | info.si_errno = 0; |
| 1887 | info.si_code = code; |
| 1888 | info.si_addr = addr; |
| 1889 | info.si_trapno = trapno; |
| 1890 | return force_sig_info(&info); |
| 1891 | } |
| 1892 | |
| 1893 | /* For the rare architectures that include trap information using |
| 1894 | * si_trapno. |
| 1895 | */ |
| 1896 | int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno, |
| 1897 | struct task_struct *t) |
| 1898 | { |
| 1899 | struct kernel_siginfo info; |
| 1900 | |
| 1901 | clear_siginfo(&info); |
| 1902 | info.si_signo = sig; |
| 1903 | info.si_errno = 0; |
| 1904 | info.si_code = code; |
| 1905 | info.si_addr = addr; |
| 1906 | info.si_trapno = trapno; |
| 1907 | return send_sig_info(info.si_signo, &info, t); |
| 1908 | } |
| 1909 | |
| 1910 | int kill_pgrp(struct pid *pid, int sig, int priv) |
| 1911 | { |
| 1912 | int ret; |
| 1913 | |
| 1914 | read_lock(&tasklist_lock); |
| 1915 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); |
| 1916 | read_unlock(&tasklist_lock); |
| 1917 | |
| 1918 | return ret; |
| 1919 | } |
| 1920 | EXPORT_SYMBOL(kill_pgrp); |
| 1921 | |
| 1922 | int kill_pid(struct pid *pid, int sig, int priv) |
| 1923 | { |
| 1924 | return kill_pid_info(sig, __si_special(priv), pid); |
| 1925 | } |
| 1926 | EXPORT_SYMBOL(kill_pid); |
| 1927 | |
| 1928 | /* |
| 1929 | * These functions support sending signals using preallocated sigqueue |
| 1930 | * structures. This is needed "because realtime applications cannot |
| 1931 | * afford to lose notifications of asynchronous events, like timer |
| 1932 | * expirations or I/O completions". In the case of POSIX Timers |
| 1933 | * we allocate the sigqueue structure from the timer_create. If this |
| 1934 | * allocation fails we are able to report the failure to the application |
| 1935 | * with an EAGAIN error. |
| 1936 | */ |
| 1937 | struct sigqueue *sigqueue_alloc(void) |
| 1938 | { |
| 1939 | return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC); |
| 1940 | } |
| 1941 | |
| 1942 | void sigqueue_free(struct sigqueue *q) |
| 1943 | { |
| 1944 | unsigned long flags; |
| 1945 | spinlock_t *lock = ¤t->sighand->siglock; |
| 1946 | |
| 1947 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
| 1948 | /* |
| 1949 | * We must hold ->siglock while testing q->list |
| 1950 | * to serialize with collect_signal() or with |
| 1951 | * __exit_signal()->flush_sigqueue(). |
| 1952 | */ |
| 1953 | spin_lock_irqsave(lock, flags); |
| 1954 | q->flags &= ~SIGQUEUE_PREALLOC; |
| 1955 | /* |
| 1956 | * If it is queued it will be freed when dequeued, |
| 1957 | * like the "regular" sigqueue. |
| 1958 | */ |
| 1959 | if (!list_empty(&q->list)) |
| 1960 | q = NULL; |
| 1961 | spin_unlock_irqrestore(lock, flags); |
| 1962 | |
| 1963 | if (q) |
| 1964 | __sigqueue_free(q); |
| 1965 | } |
| 1966 | |
| 1967 | int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) |
| 1968 | { |
| 1969 | int sig = q->info.si_signo; |
| 1970 | struct sigpending *pending; |
| 1971 | struct task_struct *t; |
| 1972 | unsigned long flags; |
| 1973 | int ret, result; |
| 1974 | |
| 1975 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
| 1976 | |
| 1977 | ret = -1; |
| 1978 | rcu_read_lock(); |
| 1979 | |
| 1980 | /* |
| 1981 | * This function is used by POSIX timers to deliver a timer signal. |
| 1982 | * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID |
| 1983 | * set), the signal must be delivered to the specific thread (queues |
| 1984 | * into t->pending). |
| 1985 | * |
| 1986 | * Where type is not PIDTYPE_PID, signals must be delivered to the |
| 1987 | * process. In this case, prefer to deliver to current if it is in |
| 1988 | * the same thread group as the target process, which avoids |
| 1989 | * unnecessarily waking up a potentially idle task. |
| 1990 | */ |
| 1991 | t = pid_task(pid, type); |
| 1992 | if (!t) |
| 1993 | goto ret; |
| 1994 | if (type != PIDTYPE_PID && same_thread_group(t, current)) |
| 1995 | t = current; |
| 1996 | if (!likely(lock_task_sighand(t, &flags))) |
| 1997 | goto ret; |
| 1998 | |
| 1999 | ret = 1; /* the signal is ignored */ |
| 2000 | result = TRACE_SIGNAL_IGNORED; |
| 2001 | if (!prepare_signal(sig, t, false)) |
| 2002 | goto out; |
| 2003 | |
| 2004 | ret = 0; |
| 2005 | if (unlikely(!list_empty(&q->list))) { |
| 2006 | /* |
| 2007 | * If an SI_TIMER entry is already queue just increment |
| 2008 | * the overrun count. |
| 2009 | */ |
| 2010 | BUG_ON(q->info.si_code != SI_TIMER); |
| 2011 | q->info.si_overrun++; |
| 2012 | result = TRACE_SIGNAL_ALREADY_PENDING; |
| 2013 | goto out; |
| 2014 | } |
| 2015 | q->info.si_overrun = 0; |
| 2016 | |
| 2017 | signalfd_notify(t, sig); |
| 2018 | pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; |
| 2019 | list_add_tail(&q->list, &pending->list); |
| 2020 | sigaddset(&pending->signal, sig); |
| 2021 | complete_signal(sig, t, type); |
| 2022 | result = TRACE_SIGNAL_DELIVERED; |
| 2023 | out: |
| 2024 | trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result); |
| 2025 | unlock_task_sighand(t, &flags); |
| 2026 | ret: |
| 2027 | rcu_read_unlock(); |
| 2028 | return ret; |
| 2029 | } |
| 2030 | |
| 2031 | static void do_notify_pidfd(struct task_struct *task) |
| 2032 | { |
| 2033 | struct pid *pid; |
| 2034 | |
| 2035 | WARN_ON(task->exit_state == 0); |
| 2036 | pid = task_pid(task); |
| 2037 | wake_up_all(&pid->wait_pidfd); |
| 2038 | } |
| 2039 | |
| 2040 | /* |
| 2041 | * Let a parent know about the death of a child. |
| 2042 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. |
| 2043 | * |
| 2044 | * Returns true if our parent ignored us and so we've switched to |
| 2045 | * self-reaping. |
| 2046 | */ |
| 2047 | bool do_notify_parent(struct task_struct *tsk, int sig) |
| 2048 | { |
| 2049 | struct kernel_siginfo info; |
| 2050 | unsigned long flags; |
| 2051 | struct sighand_struct *psig; |
| 2052 | bool autoreap = false; |
| 2053 | u64 utime, stime; |
| 2054 | |
| 2055 | WARN_ON_ONCE(sig == -1); |
| 2056 | |
| 2057 | /* do_notify_parent_cldstop should have been called instead. */ |
| 2058 | WARN_ON_ONCE(task_is_stopped_or_traced(tsk)); |
| 2059 | |
| 2060 | WARN_ON_ONCE(!tsk->ptrace && |
| 2061 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); |
| 2062 | |
| 2063 | /* Wake up all pidfd waiters */ |
| 2064 | do_notify_pidfd(tsk); |
| 2065 | |
| 2066 | if (sig != SIGCHLD) { |
| 2067 | /* |
| 2068 | * This is only possible if parent == real_parent. |
| 2069 | * Check if it has changed security domain. |
| 2070 | */ |
| 2071 | if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id)) |
| 2072 | sig = SIGCHLD; |
| 2073 | } |
| 2074 | |
| 2075 | clear_siginfo(&info); |
| 2076 | info.si_signo = sig; |
| 2077 | info.si_errno = 0; |
| 2078 | /* |
| 2079 | * We are under tasklist_lock here so our parent is tied to |
| 2080 | * us and cannot change. |
| 2081 | * |
| 2082 | * task_active_pid_ns will always return the same pid namespace |
| 2083 | * until a task passes through release_task. |
| 2084 | * |
| 2085 | * write_lock() currently calls preempt_disable() which is the |
| 2086 | * same as rcu_read_lock(), but according to Oleg, this is not |
| 2087 | * correct to rely on this |
| 2088 | */ |
| 2089 | rcu_read_lock(); |
| 2090 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent)); |
| 2091 | info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns), |
| 2092 | task_uid(tsk)); |
| 2093 | rcu_read_unlock(); |
| 2094 | |
| 2095 | task_cputime(tsk, &utime, &stime); |
| 2096 | info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime); |
| 2097 | info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime); |
| 2098 | |
| 2099 | info.si_status = tsk->exit_code & 0x7f; |
| 2100 | if (tsk->exit_code & 0x80) |
| 2101 | info.si_code = CLD_DUMPED; |
| 2102 | else if (tsk->exit_code & 0x7f) |
| 2103 | info.si_code = CLD_KILLED; |
| 2104 | else { |
| 2105 | info.si_code = CLD_EXITED; |
| 2106 | info.si_status = tsk->exit_code >> 8; |
| 2107 | } |
| 2108 | |
| 2109 | psig = tsk->parent->sighand; |
| 2110 | spin_lock_irqsave(&psig->siglock, flags); |
| 2111 | if (!tsk->ptrace && sig == SIGCHLD && |
| 2112 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
| 2113 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { |
| 2114 | /* |
| 2115 | * We are exiting and our parent doesn't care. POSIX.1 |
| 2116 | * defines special semantics for setting SIGCHLD to SIG_IGN |
| 2117 | * or setting the SA_NOCLDWAIT flag: we should be reaped |
| 2118 | * automatically and not left for our parent's wait4 call. |
| 2119 | * Rather than having the parent do it as a magic kind of |
| 2120 | * signal handler, we just set this to tell do_exit that we |
| 2121 | * can be cleaned up without becoming a zombie. Note that |
| 2122 | * we still call __wake_up_parent in this case, because a |
| 2123 | * blocked sys_wait4 might now return -ECHILD. |
| 2124 | * |
| 2125 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT |
| 2126 | * is implementation-defined: we do (if you don't want |
| 2127 | * it, just use SIG_IGN instead). |
| 2128 | */ |
| 2129 | autoreap = true; |
| 2130 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) |
| 2131 | sig = 0; |
| 2132 | } |
| 2133 | /* |
| 2134 | * Send with __send_signal as si_pid and si_uid are in the |
| 2135 | * parent's namespaces. |
| 2136 | */ |
| 2137 | if (valid_signal(sig) && sig) |
| 2138 | __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false); |
| 2139 | __wake_up_parent(tsk, tsk->parent); |
| 2140 | spin_unlock_irqrestore(&psig->siglock, flags); |
| 2141 | |
| 2142 | return autoreap; |
| 2143 | } |
| 2144 | |
| 2145 | /** |
| 2146 | * do_notify_parent_cldstop - notify parent of stopped/continued state change |
| 2147 | * @tsk: task reporting the state change |
| 2148 | * @for_ptracer: the notification is for ptracer |
| 2149 | * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report |
| 2150 | * |
| 2151 | * Notify @tsk's parent that the stopped/continued state has changed. If |
| 2152 | * @for_ptracer is %false, @tsk's group leader notifies to its real parent. |
| 2153 | * If %true, @tsk reports to @tsk->parent which should be the ptracer. |
| 2154 | * |
| 2155 | * CONTEXT: |
| 2156 | * Must be called with tasklist_lock at least read locked. |
| 2157 | */ |
| 2158 | static void do_notify_parent_cldstop(struct task_struct *tsk, |
| 2159 | bool for_ptracer, int why) |
| 2160 | { |
| 2161 | struct kernel_siginfo info; |
| 2162 | unsigned long flags; |
| 2163 | struct task_struct *parent; |
| 2164 | struct sighand_struct *sighand; |
| 2165 | u64 utime, stime; |
| 2166 | |
| 2167 | if (for_ptracer) { |
| 2168 | parent = tsk->parent; |
| 2169 | } else { |
| 2170 | tsk = tsk->group_leader; |
| 2171 | parent = tsk->real_parent; |
| 2172 | } |
| 2173 | |
| 2174 | clear_siginfo(&info); |
| 2175 | info.si_signo = SIGCHLD; |
| 2176 | info.si_errno = 0; |
| 2177 | /* |
| 2178 | * see comment in do_notify_parent() about the following 4 lines |
| 2179 | */ |
| 2180 | rcu_read_lock(); |
| 2181 | info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent)); |
| 2182 | info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk)); |
| 2183 | rcu_read_unlock(); |
| 2184 | |
| 2185 | task_cputime(tsk, &utime, &stime); |
| 2186 | info.si_utime = nsec_to_clock_t(utime); |
| 2187 | info.si_stime = nsec_to_clock_t(stime); |
| 2188 | |
| 2189 | info.si_code = why; |
| 2190 | switch (why) { |
| 2191 | case CLD_CONTINUED: |
| 2192 | info.si_status = SIGCONT; |
| 2193 | break; |
| 2194 | case CLD_STOPPED: |
| 2195 | info.si_status = tsk->signal->group_exit_code & 0x7f; |
| 2196 | break; |
| 2197 | case CLD_TRAPPED: |
| 2198 | info.si_status = tsk->exit_code & 0x7f; |
| 2199 | break; |
| 2200 | default: |
| 2201 | BUG(); |
| 2202 | } |
| 2203 | |
| 2204 | sighand = parent->sighand; |
| 2205 | spin_lock_irqsave(&sighand->siglock, flags); |
| 2206 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && |
| 2207 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) |
| 2208 | send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID); |
| 2209 | /* |
| 2210 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. |
| 2211 | */ |
| 2212 | __wake_up_parent(tsk, parent); |
| 2213 | spin_unlock_irqrestore(&sighand->siglock, flags); |
| 2214 | } |
| 2215 | |
| 2216 | /* |
| 2217 | * This must be called with current->sighand->siglock held. |
| 2218 | * |
| 2219 | * This should be the path for all ptrace stops. |
| 2220 | * We always set current->last_siginfo while stopped here. |
| 2221 | * That makes it a way to test a stopped process for |
| 2222 | * being ptrace-stopped vs being job-control-stopped. |
| 2223 | * |
| 2224 | * Returns the signal the ptracer requested the code resume |
| 2225 | * with. If the code did not stop because the tracer is gone, |
| 2226 | * the stop signal remains unchanged unless clear_code. |
| 2227 | */ |
| 2228 | static int ptrace_stop(int exit_code, int why, unsigned long message, |
| 2229 | kernel_siginfo_t *info) |
| 2230 | __releases(¤t->sighand->siglock) |
| 2231 | __acquires(¤t->sighand->siglock) |
| 2232 | { |
| 2233 | bool gstop_done = false; |
| 2234 | |
| 2235 | if (arch_ptrace_stop_needed()) { |
| 2236 | /* |
| 2237 | * The arch code has something special to do before a |
| 2238 | * ptrace stop. This is allowed to block, e.g. for faults |
| 2239 | * on user stack pages. We can't keep the siglock while |
| 2240 | * calling arch_ptrace_stop, so we must release it now. |
| 2241 | * To preserve proper semantics, we must do this before |
| 2242 | * any signal bookkeeping like checking group_stop_count. |
| 2243 | */ |
| 2244 | spin_unlock_irq(¤t->sighand->siglock); |
| 2245 | arch_ptrace_stop(); |
| 2246 | spin_lock_irq(¤t->sighand->siglock); |
| 2247 | } |
| 2248 | |
| 2249 | /* |
| 2250 | * After this point ptrace_signal_wake_up or signal_wake_up |
| 2251 | * will clear TASK_TRACED if ptrace_unlink happens or a fatal |
| 2252 | * signal comes in. Handle previous ptrace_unlinks and fatal |
| 2253 | * signals here to prevent ptrace_stop sleeping in schedule. |
| 2254 | */ |
| 2255 | if (!current->ptrace || __fatal_signal_pending(current)) |
| 2256 | return exit_code; |
| 2257 | |
| 2258 | set_special_state(TASK_TRACED); |
| 2259 | current->jobctl |= JOBCTL_TRACED; |
| 2260 | |
| 2261 | /* |
| 2262 | * We're committing to trapping. TRACED should be visible before |
| 2263 | * TRAPPING is cleared; otherwise, the tracer might fail do_wait(). |
| 2264 | * Also, transition to TRACED and updates to ->jobctl should be |
| 2265 | * atomic with respect to siglock and should be done after the arch |
| 2266 | * hook as siglock is released and regrabbed across it. |
| 2267 | * |
| 2268 | * TRACER TRACEE |
| 2269 | * |
| 2270 | * ptrace_attach() |
| 2271 | * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED) |
| 2272 | * do_wait() |
| 2273 | * set_current_state() smp_wmb(); |
| 2274 | * ptrace_do_wait() |
| 2275 | * wait_task_stopped() |
| 2276 | * task_stopped_code() |
| 2277 | * [L] task_is_traced() [S] task_clear_jobctl_trapping(); |
| 2278 | */ |
| 2279 | smp_wmb(); |
| 2280 | |
| 2281 | current->ptrace_message = message; |
| 2282 | current->last_siginfo = info; |
| 2283 | current->exit_code = exit_code; |
| 2284 | |
| 2285 | /* |
| 2286 | * If @why is CLD_STOPPED, we're trapping to participate in a group |
| 2287 | * stop. Do the bookkeeping. Note that if SIGCONT was delievered |
| 2288 | * across siglock relocks since INTERRUPT was scheduled, PENDING |
| 2289 | * could be clear now. We act as if SIGCONT is received after |
| 2290 | * TASK_TRACED is entered - ignore it. |
| 2291 | */ |
| 2292 | if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING)) |
| 2293 | gstop_done = task_participate_group_stop(current); |
| 2294 | |
| 2295 | /* any trap clears pending STOP trap, STOP trap clears NOTIFY */ |
| 2296 | task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP); |
| 2297 | if (info && info->si_code >> 8 == PTRACE_EVENT_STOP) |
| 2298 | task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY); |
| 2299 | |
| 2300 | /* entering a trap, clear TRAPPING */ |
| 2301 | task_clear_jobctl_trapping(current); |
| 2302 | |
| 2303 | spin_unlock_irq(¤t->sighand->siglock); |
| 2304 | read_lock(&tasklist_lock); |
| 2305 | /* |
| 2306 | * Notify parents of the stop. |
| 2307 | * |
| 2308 | * While ptraced, there are two parents - the ptracer and |
| 2309 | * the real_parent of the group_leader. The ptracer should |
| 2310 | * know about every stop while the real parent is only |
| 2311 | * interested in the completion of group stop. The states |
| 2312 | * for the two don't interact with each other. Notify |
| 2313 | * separately unless they're gonna be duplicates. |
| 2314 | */ |
| 2315 | if (current->ptrace) |
| 2316 | do_notify_parent_cldstop(current, true, why); |
| 2317 | if (gstop_done && (!current->ptrace || ptrace_reparented(current))) |
| 2318 | do_notify_parent_cldstop(current, false, why); |
| 2319 | |
| 2320 | /* |
| 2321 | * The previous do_notify_parent_cldstop() invocation woke ptracer. |
| 2322 | * One a PREEMPTION kernel this can result in preemption requirement |
| 2323 | * which will be fulfilled after read_unlock() and the ptracer will be |
| 2324 | * put on the CPU. |
| 2325 | * The ptracer is in wait_task_inactive(, __TASK_TRACED) waiting for |
| 2326 | * this task wait in schedule(). If this task gets preempted then it |
| 2327 | * remains enqueued on the runqueue. The ptracer will observe this and |
| 2328 | * then sleep for a delay of one HZ tick. In the meantime this task |
| 2329 | * gets scheduled, enters schedule() and will wait for the ptracer. |
| 2330 | * |
| 2331 | * This preemption point is not bad from a correctness point of |
| 2332 | * view but extends the runtime by one HZ tick time due to the |
| 2333 | * ptracer's sleep. The preempt-disable section ensures that there |
| 2334 | * will be no preemption between unlock and schedule() and so |
| 2335 | * improving the performance since the ptracer will observe that |
| 2336 | * the tracee is scheduled out once it gets on the CPU. |
| 2337 | * |
| 2338 | * On PREEMPT_RT locking tasklist_lock does not disable preemption. |
| 2339 | * Therefore the task can be preempted after do_notify_parent_cldstop() |
| 2340 | * before unlocking tasklist_lock so there is no benefit in doing this. |
| 2341 | * |
| 2342 | * In fact disabling preemption is harmful on PREEMPT_RT because |
| 2343 | * the spinlock_t in cgroup_enter_frozen() must not be acquired |
| 2344 | * with preemption disabled due to the 'sleeping' spinlock |
| 2345 | * substitution of RT. |
| 2346 | */ |
| 2347 | if (!IS_ENABLED(CONFIG_PREEMPT_RT)) |
| 2348 | preempt_disable(); |
| 2349 | read_unlock(&tasklist_lock); |
| 2350 | cgroup_enter_frozen(); |
| 2351 | if (!IS_ENABLED(CONFIG_PREEMPT_RT)) |
| 2352 | preempt_enable_no_resched(); |
| 2353 | schedule(); |
| 2354 | cgroup_leave_frozen(true); |
| 2355 | |
| 2356 | /* |
| 2357 | * We are back. Now reacquire the siglock before touching |
| 2358 | * last_siginfo, so that we are sure to have synchronized with |
| 2359 | * any signal-sending on another CPU that wants to examine it. |
| 2360 | */ |
| 2361 | spin_lock_irq(¤t->sighand->siglock); |
| 2362 | exit_code = current->exit_code; |
| 2363 | current->last_siginfo = NULL; |
| 2364 | current->ptrace_message = 0; |
| 2365 | current->exit_code = 0; |
| 2366 | |
| 2367 | /* LISTENING can be set only during STOP traps, clear it */ |
| 2368 | current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN); |
| 2369 | |
| 2370 | /* |
| 2371 | * Queued signals ignored us while we were stopped for tracing. |
| 2372 | * So check for any that we should take before resuming user mode. |
| 2373 | * This sets TIF_SIGPENDING, but never clears it. |
| 2374 | */ |
| 2375 | recalc_sigpending_tsk(current); |
| 2376 | return exit_code; |
| 2377 | } |
| 2378 | |
| 2379 | static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message) |
| 2380 | { |
| 2381 | kernel_siginfo_t info; |
| 2382 | |
| 2383 | clear_siginfo(&info); |
| 2384 | info.si_signo = signr; |
| 2385 | info.si_code = exit_code; |
| 2386 | info.si_pid = task_pid_vnr(current); |
| 2387 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
| 2388 | |
| 2389 | /* Let the debugger run. */ |
| 2390 | return ptrace_stop(exit_code, why, message, &info); |
| 2391 | } |
| 2392 | |
| 2393 | int ptrace_notify(int exit_code, unsigned long message) |
| 2394 | { |
| 2395 | int signr; |
| 2396 | |
| 2397 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); |
| 2398 | if (unlikely(task_work_pending(current))) |
| 2399 | task_work_run(); |
| 2400 | |
| 2401 | spin_lock_irq(¤t->sighand->siglock); |
| 2402 | signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message); |
| 2403 | spin_unlock_irq(¤t->sighand->siglock); |
| 2404 | return signr; |
| 2405 | } |
| 2406 | |
| 2407 | /** |
| 2408 | * do_signal_stop - handle group stop for SIGSTOP and other stop signals |
| 2409 | * @signr: signr causing group stop if initiating |
| 2410 | * |
| 2411 | * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr |
| 2412 | * and participate in it. If already set, participate in the existing |
| 2413 | * group stop. If participated in a group stop (and thus slept), %true is |
| 2414 | * returned with siglock released. |
| 2415 | * |
| 2416 | * If ptraced, this function doesn't handle stop itself. Instead, |
| 2417 | * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock |
| 2418 | * untouched. The caller must ensure that INTERRUPT trap handling takes |
| 2419 | * places afterwards. |
| 2420 | * |
| 2421 | * CONTEXT: |
| 2422 | * Must be called with @current->sighand->siglock held, which is released |
| 2423 | * on %true return. |
| 2424 | * |
| 2425 | * RETURNS: |
| 2426 | * %false if group stop is already cancelled or ptrace trap is scheduled. |
| 2427 | * %true if participated in group stop. |
| 2428 | */ |
| 2429 | static bool do_signal_stop(int signr) |
| 2430 | __releases(¤t->sighand->siglock) |
| 2431 | { |
| 2432 | struct signal_struct *sig = current->signal; |
| 2433 | |
| 2434 | if (!(current->jobctl & JOBCTL_STOP_PENDING)) { |
| 2435 | unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME; |
| 2436 | struct task_struct *t; |
| 2437 | |
| 2438 | /* signr will be recorded in task->jobctl for retries */ |
| 2439 | WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK); |
| 2440 | |
| 2441 | if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) || |
| 2442 | unlikely(sig->flags & SIGNAL_GROUP_EXIT) || |
| 2443 | unlikely(sig->group_exec_task)) |
| 2444 | return false; |
| 2445 | /* |
| 2446 | * There is no group stop already in progress. We must |
| 2447 | * initiate one now. |
| 2448 | * |
| 2449 | * While ptraced, a task may be resumed while group stop is |
| 2450 | * still in effect and then receive a stop signal and |
| 2451 | * initiate another group stop. This deviates from the |
| 2452 | * usual behavior as two consecutive stop signals can't |
| 2453 | * cause two group stops when !ptraced. That is why we |
| 2454 | * also check !task_is_stopped(t) below. |
| 2455 | * |
| 2456 | * The condition can be distinguished by testing whether |
| 2457 | * SIGNAL_STOP_STOPPED is already set. Don't generate |
| 2458 | * group_exit_code in such case. |
| 2459 | * |
| 2460 | * This is not necessary for SIGNAL_STOP_CONTINUED because |
| 2461 | * an intervening stop signal is required to cause two |
| 2462 | * continued events regardless of ptrace. |
| 2463 | */ |
| 2464 | if (!(sig->flags & SIGNAL_STOP_STOPPED)) |
| 2465 | sig->group_exit_code = signr; |
| 2466 | |
| 2467 | sig->group_stop_count = 0; |
| 2468 | |
| 2469 | if (task_set_jobctl_pending(current, signr | gstop)) |
| 2470 | sig->group_stop_count++; |
| 2471 | |
| 2472 | t = current; |
| 2473 | while_each_thread(current, t) { |
| 2474 | /* |
| 2475 | * Setting state to TASK_STOPPED for a group |
| 2476 | * stop is always done with the siglock held, |
| 2477 | * so this check has no races. |
| 2478 | */ |
| 2479 | if (!task_is_stopped(t) && |
| 2480 | task_set_jobctl_pending(t, signr | gstop)) { |
| 2481 | sig->group_stop_count++; |
| 2482 | if (likely(!(t->ptrace & PT_SEIZED))) |
| 2483 | signal_wake_up(t, 0); |
| 2484 | else |
| 2485 | ptrace_trap_notify(t); |
| 2486 | } |
| 2487 | } |
| 2488 | } |
| 2489 | |
| 2490 | if (likely(!current->ptrace)) { |
| 2491 | int notify = 0; |
| 2492 | |
| 2493 | /* |
| 2494 | * If there are no other threads in the group, or if there |
| 2495 | * is a group stop in progress and we are the last to stop, |
| 2496 | * report to the parent. |
| 2497 | */ |
| 2498 | if (task_participate_group_stop(current)) |
| 2499 | notify = CLD_STOPPED; |
| 2500 | |
| 2501 | current->jobctl |= JOBCTL_STOPPED; |
| 2502 | set_special_state(TASK_STOPPED); |
| 2503 | spin_unlock_irq(¤t->sighand->siglock); |
| 2504 | |
| 2505 | /* |
| 2506 | * Notify the parent of the group stop completion. Because |
| 2507 | * we're not holding either the siglock or tasklist_lock |
| 2508 | * here, ptracer may attach inbetween; however, this is for |
| 2509 | * group stop and should always be delivered to the real |
| 2510 | * parent of the group leader. The new ptracer will get |
| 2511 | * its notification when this task transitions into |
| 2512 | * TASK_TRACED. |
| 2513 | */ |
| 2514 | if (notify) { |
| 2515 | read_lock(&tasklist_lock); |
| 2516 | do_notify_parent_cldstop(current, false, notify); |
| 2517 | read_unlock(&tasklist_lock); |
| 2518 | } |
| 2519 | |
| 2520 | /* Now we don't run again until woken by SIGCONT or SIGKILL */ |
| 2521 | cgroup_enter_frozen(); |
| 2522 | schedule(); |
| 2523 | return true; |
| 2524 | } else { |
| 2525 | /* |
| 2526 | * While ptraced, group stop is handled by STOP trap. |
| 2527 | * Schedule it and let the caller deal with it. |
| 2528 | */ |
| 2529 | task_set_jobctl_pending(current, JOBCTL_TRAP_STOP); |
| 2530 | return false; |
| 2531 | } |
| 2532 | } |
| 2533 | |
| 2534 | /** |
| 2535 | * do_jobctl_trap - take care of ptrace jobctl traps |
| 2536 | * |
| 2537 | * When PT_SEIZED, it's used for both group stop and explicit |
| 2538 | * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with |
| 2539 | * accompanying siginfo. If stopped, lower eight bits of exit_code contain |
| 2540 | * the stop signal; otherwise, %SIGTRAP. |
| 2541 | * |
| 2542 | * When !PT_SEIZED, it's used only for group stop trap with stop signal |
| 2543 | * number as exit_code and no siginfo. |
| 2544 | * |
| 2545 | * CONTEXT: |
| 2546 | * Must be called with @current->sighand->siglock held, which may be |
| 2547 | * released and re-acquired before returning with intervening sleep. |
| 2548 | */ |
| 2549 | static void do_jobctl_trap(void) |
| 2550 | { |
| 2551 | struct signal_struct *signal = current->signal; |
| 2552 | int signr = current->jobctl & JOBCTL_STOP_SIGMASK; |
| 2553 | |
| 2554 | if (current->ptrace & PT_SEIZED) { |
| 2555 | if (!signal->group_stop_count && |
| 2556 | !(signal->flags & SIGNAL_STOP_STOPPED)) |
| 2557 | signr = SIGTRAP; |
| 2558 | WARN_ON_ONCE(!signr); |
| 2559 | ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8), |
| 2560 | CLD_STOPPED, 0); |
| 2561 | } else { |
| 2562 | WARN_ON_ONCE(!signr); |
| 2563 | ptrace_stop(signr, CLD_STOPPED, 0, NULL); |
| 2564 | } |
| 2565 | } |
| 2566 | |
| 2567 | /** |
| 2568 | * do_freezer_trap - handle the freezer jobctl trap |
| 2569 | * |
| 2570 | * Puts the task into frozen state, if only the task is not about to quit. |
| 2571 | * In this case it drops JOBCTL_TRAP_FREEZE. |
| 2572 | * |
| 2573 | * CONTEXT: |
| 2574 | * Must be called with @current->sighand->siglock held, |
| 2575 | * which is always released before returning. |
| 2576 | */ |
| 2577 | static void do_freezer_trap(void) |
| 2578 | __releases(¤t->sighand->siglock) |
| 2579 | { |
| 2580 | /* |
| 2581 | * If there are other trap bits pending except JOBCTL_TRAP_FREEZE, |
| 2582 | * let's make another loop to give it a chance to be handled. |
| 2583 | * In any case, we'll return back. |
| 2584 | */ |
| 2585 | if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) != |
| 2586 | JOBCTL_TRAP_FREEZE) { |
| 2587 | spin_unlock_irq(¤t->sighand->siglock); |
| 2588 | return; |
| 2589 | } |
| 2590 | |
| 2591 | /* |
| 2592 | * Now we're sure that there is no pending fatal signal and no |
| 2593 | * pending traps. Clear TIF_SIGPENDING to not get out of schedule() |
| 2594 | * immediately (if there is a non-fatal signal pending), and |
| 2595 | * put the task into sleep. |
| 2596 | */ |
| 2597 | __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); |
| 2598 | clear_thread_flag(TIF_SIGPENDING); |
| 2599 | spin_unlock_irq(¤t->sighand->siglock); |
| 2600 | cgroup_enter_frozen(); |
| 2601 | schedule(); |
| 2602 | } |
| 2603 | |
| 2604 | static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type) |
| 2605 | { |
| 2606 | /* |
| 2607 | * We do not check sig_kernel_stop(signr) but set this marker |
| 2608 | * unconditionally because we do not know whether debugger will |
| 2609 | * change signr. This flag has no meaning unless we are going |
| 2610 | * to stop after return from ptrace_stop(). In this case it will |
| 2611 | * be checked in do_signal_stop(), we should only stop if it was |
| 2612 | * not cleared by SIGCONT while we were sleeping. See also the |
| 2613 | * comment in dequeue_signal(). |
| 2614 | */ |
| 2615 | current->jobctl |= JOBCTL_STOP_DEQUEUED; |
| 2616 | signr = ptrace_stop(signr, CLD_TRAPPED, 0, info); |
| 2617 | |
| 2618 | /* We're back. Did the debugger cancel the sig? */ |
| 2619 | if (signr == 0) |
| 2620 | return signr; |
| 2621 | |
| 2622 | /* |
| 2623 | * Update the siginfo structure if the signal has |
| 2624 | * changed. If the debugger wanted something |
| 2625 | * specific in the siginfo structure then it should |
| 2626 | * have updated *info via PTRACE_SETSIGINFO. |
| 2627 | */ |
| 2628 | if (signr != info->si_signo) { |
| 2629 | clear_siginfo(info); |
| 2630 | info->si_signo = signr; |
| 2631 | info->si_errno = 0; |
| 2632 | info->si_code = SI_USER; |
| 2633 | rcu_read_lock(); |
| 2634 | info->si_pid = task_pid_vnr(current->parent); |
| 2635 | info->si_uid = from_kuid_munged(current_user_ns(), |
| 2636 | task_uid(current->parent)); |
| 2637 | rcu_read_unlock(); |
| 2638 | } |
| 2639 | |
| 2640 | /* If the (new) signal is now blocked, requeue it. */ |
| 2641 | if (sigismember(¤t->blocked, signr) || |
| 2642 | fatal_signal_pending(current)) { |
| 2643 | send_signal_locked(signr, info, current, type); |
| 2644 | signr = 0; |
| 2645 | } |
| 2646 | |
| 2647 | return signr; |
| 2648 | } |
| 2649 | |
| 2650 | static void hide_si_addr_tag_bits(struct ksignal *ksig) |
| 2651 | { |
| 2652 | switch (siginfo_layout(ksig->sig, ksig->info.si_code)) { |
| 2653 | case SIL_FAULT: |
| 2654 | case SIL_FAULT_TRAPNO: |
| 2655 | case SIL_FAULT_MCEERR: |
| 2656 | case SIL_FAULT_BNDERR: |
| 2657 | case SIL_FAULT_PKUERR: |
| 2658 | case SIL_FAULT_PERF_EVENT: |
| 2659 | ksig->info.si_addr = arch_untagged_si_addr( |
| 2660 | ksig->info.si_addr, ksig->sig, ksig->info.si_code); |
| 2661 | break; |
| 2662 | case SIL_KILL: |
| 2663 | case SIL_TIMER: |
| 2664 | case SIL_POLL: |
| 2665 | case SIL_CHLD: |
| 2666 | case SIL_RT: |
| 2667 | case SIL_SYS: |
| 2668 | break; |
| 2669 | } |
| 2670 | } |
| 2671 | |
| 2672 | bool get_signal(struct ksignal *ksig) |
| 2673 | { |
| 2674 | struct sighand_struct *sighand = current->sighand; |
| 2675 | struct signal_struct *signal = current->signal; |
| 2676 | int signr; |
| 2677 | |
| 2678 | clear_notify_signal(); |
| 2679 | if (unlikely(task_work_pending(current))) |
| 2680 | task_work_run(); |
| 2681 | |
| 2682 | if (!task_sigpending(current)) |
| 2683 | return false; |
| 2684 | |
| 2685 | if (unlikely(uprobe_deny_signal())) |
| 2686 | return false; |
| 2687 | |
| 2688 | /* |
| 2689 | * Do this once, we can't return to user-mode if freezing() == T. |
| 2690 | * do_signal_stop() and ptrace_stop() do freezable_schedule() and |
| 2691 | * thus do not need another check after return. |
| 2692 | */ |
| 2693 | try_to_freeze(); |
| 2694 | |
| 2695 | relock: |
| 2696 | spin_lock_irq(&sighand->siglock); |
| 2697 | |
| 2698 | /* |
| 2699 | * Every stopped thread goes here after wakeup. Check to see if |
| 2700 | * we should notify the parent, prepare_signal(SIGCONT) encodes |
| 2701 | * the CLD_ si_code into SIGNAL_CLD_MASK bits. |
| 2702 | */ |
| 2703 | if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { |
| 2704 | int why; |
| 2705 | |
| 2706 | if (signal->flags & SIGNAL_CLD_CONTINUED) |
| 2707 | why = CLD_CONTINUED; |
| 2708 | else |
| 2709 | why = CLD_STOPPED; |
| 2710 | |
| 2711 | signal->flags &= ~SIGNAL_CLD_MASK; |
| 2712 | |
| 2713 | spin_unlock_irq(&sighand->siglock); |
| 2714 | |
| 2715 | /* |
| 2716 | * Notify the parent that we're continuing. This event is |
| 2717 | * always per-process and doesn't make whole lot of sense |
| 2718 | * for ptracers, who shouldn't consume the state via |
| 2719 | * wait(2) either, but, for backward compatibility, notify |
| 2720 | * the ptracer of the group leader too unless it's gonna be |
| 2721 | * a duplicate. |
| 2722 | */ |
| 2723 | read_lock(&tasklist_lock); |
| 2724 | do_notify_parent_cldstop(current, false, why); |
| 2725 | |
| 2726 | if (ptrace_reparented(current->group_leader)) |
| 2727 | do_notify_parent_cldstop(current->group_leader, |
| 2728 | true, why); |
| 2729 | read_unlock(&tasklist_lock); |
| 2730 | |
| 2731 | goto relock; |
| 2732 | } |
| 2733 | |
| 2734 | for (;;) { |
| 2735 | struct k_sigaction *ka; |
| 2736 | enum pid_type type; |
| 2737 | |
| 2738 | /* Has this task already been marked for death? */ |
| 2739 | if ((signal->flags & SIGNAL_GROUP_EXIT) || |
| 2740 | signal->group_exec_task) { |
| 2741 | clear_siginfo(&ksig->info); |
| 2742 | ksig->info.si_signo = signr = SIGKILL; |
| 2743 | sigdelset(¤t->pending.signal, SIGKILL); |
| 2744 | trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, |
| 2745 | &sighand->action[SIGKILL - 1]); |
| 2746 | recalc_sigpending(); |
| 2747 | goto fatal; |
| 2748 | } |
| 2749 | |
| 2750 | if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && |
| 2751 | do_signal_stop(0)) |
| 2752 | goto relock; |
| 2753 | |
| 2754 | if (unlikely(current->jobctl & |
| 2755 | (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) { |
| 2756 | if (current->jobctl & JOBCTL_TRAP_MASK) { |
| 2757 | do_jobctl_trap(); |
| 2758 | spin_unlock_irq(&sighand->siglock); |
| 2759 | } else if (current->jobctl & JOBCTL_TRAP_FREEZE) |
| 2760 | do_freezer_trap(); |
| 2761 | |
| 2762 | goto relock; |
| 2763 | } |
| 2764 | |
| 2765 | /* |
| 2766 | * If the task is leaving the frozen state, let's update |
| 2767 | * cgroup counters and reset the frozen bit. |
| 2768 | */ |
| 2769 | if (unlikely(cgroup_task_frozen(current))) { |
| 2770 | spin_unlock_irq(&sighand->siglock); |
| 2771 | cgroup_leave_frozen(false); |
| 2772 | goto relock; |
| 2773 | } |
| 2774 | |
| 2775 | /* |
| 2776 | * Signals generated by the execution of an instruction |
| 2777 | * need to be delivered before any other pending signals |
| 2778 | * so that the instruction pointer in the signal stack |
| 2779 | * frame points to the faulting instruction. |
| 2780 | */ |
| 2781 | type = PIDTYPE_PID; |
| 2782 | signr = dequeue_synchronous_signal(&ksig->info); |
| 2783 | if (!signr) |
| 2784 | signr = dequeue_signal(current, ¤t->blocked, |
| 2785 | &ksig->info, &type); |
| 2786 | |
| 2787 | if (!signr) |
| 2788 | break; /* will return 0 */ |
| 2789 | |
| 2790 | if (unlikely(current->ptrace) && (signr != SIGKILL) && |
| 2791 | !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) { |
| 2792 | signr = ptrace_signal(signr, &ksig->info, type); |
| 2793 | if (!signr) |
| 2794 | continue; |
| 2795 | } |
| 2796 | |
| 2797 | ka = &sighand->action[signr-1]; |
| 2798 | |
| 2799 | /* Trace actually delivered signals. */ |
| 2800 | trace_signal_deliver(signr, &ksig->info, ka); |
| 2801 | |
| 2802 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ |
| 2803 | continue; |
| 2804 | if (ka->sa.sa_handler != SIG_DFL) { |
| 2805 | /* Run the handler. */ |
| 2806 | ksig->ka = *ka; |
| 2807 | |
| 2808 | if (ka->sa.sa_flags & SA_ONESHOT) |
| 2809 | ka->sa.sa_handler = SIG_DFL; |
| 2810 | |
| 2811 | break; /* will return non-zero "signr" value */ |
| 2812 | } |
| 2813 | |
| 2814 | /* |
| 2815 | * Now we are doing the default action for this signal. |
| 2816 | */ |
| 2817 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ |
| 2818 | continue; |
| 2819 | |
| 2820 | /* |
| 2821 | * Global init gets no signals it doesn't want. |
| 2822 | * Container-init gets no signals it doesn't want from same |
| 2823 | * container. |
| 2824 | * |
| 2825 | * Note that if global/container-init sees a sig_kernel_only() |
| 2826 | * signal here, the signal must have been generated internally |
| 2827 | * or must have come from an ancestor namespace. In either |
| 2828 | * case, the signal cannot be dropped. |
| 2829 | */ |
| 2830 | if (unlikely(signal->flags & SIGNAL_UNKILLABLE) && |
| 2831 | !sig_kernel_only(signr)) |
| 2832 | continue; |
| 2833 | |
| 2834 | if (sig_kernel_stop(signr)) { |
| 2835 | /* |
| 2836 | * The default action is to stop all threads in |
| 2837 | * the thread group. The job control signals |
| 2838 | * do nothing in an orphaned pgrp, but SIGSTOP |
| 2839 | * always works. Note that siglock needs to be |
| 2840 | * dropped during the call to is_orphaned_pgrp() |
| 2841 | * because of lock ordering with tasklist_lock. |
| 2842 | * This allows an intervening SIGCONT to be posted. |
| 2843 | * We need to check for that and bail out if necessary. |
| 2844 | */ |
| 2845 | if (signr != SIGSTOP) { |
| 2846 | spin_unlock_irq(&sighand->siglock); |
| 2847 | |
| 2848 | /* signals can be posted during this window */ |
| 2849 | |
| 2850 | if (is_current_pgrp_orphaned()) |
| 2851 | goto relock; |
| 2852 | |
| 2853 | spin_lock_irq(&sighand->siglock); |
| 2854 | } |
| 2855 | |
| 2856 | if (likely(do_signal_stop(ksig->info.si_signo))) { |
| 2857 | /* It released the siglock. */ |
| 2858 | goto relock; |
| 2859 | } |
| 2860 | |
| 2861 | /* |
| 2862 | * We didn't actually stop, due to a race |
| 2863 | * with SIGCONT or something like that. |
| 2864 | */ |
| 2865 | continue; |
| 2866 | } |
| 2867 | |
| 2868 | fatal: |
| 2869 | spin_unlock_irq(&sighand->siglock); |
| 2870 | if (unlikely(cgroup_task_frozen(current))) |
| 2871 | cgroup_leave_frozen(true); |
| 2872 | |
| 2873 | /* |
| 2874 | * Anything else is fatal, maybe with a core dump. |
| 2875 | */ |
| 2876 | current->flags |= PF_SIGNALED; |
| 2877 | |
| 2878 | if (sig_kernel_coredump(signr)) { |
| 2879 | if (print_fatal_signals) |
| 2880 | print_fatal_signal(ksig->info.si_signo); |
| 2881 | proc_coredump_connector(current); |
| 2882 | /* |
| 2883 | * If it was able to dump core, this kills all |
| 2884 | * other threads in the group and synchronizes with |
| 2885 | * their demise. If we lost the race with another |
| 2886 | * thread getting here, it set group_exit_code |
| 2887 | * first and our do_group_exit call below will use |
| 2888 | * that value and ignore the one we pass it. |
| 2889 | */ |
| 2890 | do_coredump(&ksig->info); |
| 2891 | } |
| 2892 | |
| 2893 | /* |
| 2894 | * PF_USER_WORKER threads will catch and exit on fatal signals |
| 2895 | * themselves. They have cleanup that must be performed, so |
| 2896 | * we cannot call do_exit() on their behalf. |
| 2897 | */ |
| 2898 | if (current->flags & PF_USER_WORKER) |
| 2899 | goto out; |
| 2900 | |
| 2901 | /* |
| 2902 | * Death signals, no core dump. |
| 2903 | */ |
| 2904 | do_group_exit(ksig->info.si_signo); |
| 2905 | /* NOTREACHED */ |
| 2906 | } |
| 2907 | spin_unlock_irq(&sighand->siglock); |
| 2908 | out: |
| 2909 | ksig->sig = signr; |
| 2910 | |
| 2911 | if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS)) |
| 2912 | hide_si_addr_tag_bits(ksig); |
| 2913 | |
| 2914 | return ksig->sig > 0; |
| 2915 | } |
| 2916 | |
| 2917 | /** |
| 2918 | * signal_delivered - called after signal delivery to update blocked signals |
| 2919 | * @ksig: kernel signal struct |
| 2920 | * @stepping: nonzero if debugger single-step or block-step in use |
| 2921 | * |
| 2922 | * This function should be called when a signal has successfully been |
| 2923 | * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask |
| 2924 | * is always blocked), and the signal itself is blocked unless %SA_NODEFER |
| 2925 | * is set in @ksig->ka.sa.sa_flags. Tracing is notified. |
| 2926 | */ |
| 2927 | static void signal_delivered(struct ksignal *ksig, int stepping) |
| 2928 | { |
| 2929 | sigset_t blocked; |
| 2930 | |
| 2931 | /* A signal was successfully delivered, and the |
| 2932 | saved sigmask was stored on the signal frame, |
| 2933 | and will be restored by sigreturn. So we can |
| 2934 | simply clear the restore sigmask flag. */ |
| 2935 | clear_restore_sigmask(); |
| 2936 | |
| 2937 | sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask); |
| 2938 | if (!(ksig->ka.sa.sa_flags & SA_NODEFER)) |
| 2939 | sigaddset(&blocked, ksig->sig); |
| 2940 | set_current_blocked(&blocked); |
| 2941 | if (current->sas_ss_flags & SS_AUTODISARM) |
| 2942 | sas_ss_reset(current); |
| 2943 | if (stepping) |
| 2944 | ptrace_notify(SIGTRAP, 0); |
| 2945 | } |
| 2946 | |
| 2947 | void signal_setup_done(int failed, struct ksignal *ksig, int stepping) |
| 2948 | { |
| 2949 | if (failed) |
| 2950 | force_sigsegv(ksig->sig); |
| 2951 | else |
| 2952 | signal_delivered(ksig, stepping); |
| 2953 | } |
| 2954 | |
| 2955 | /* |
| 2956 | * It could be that complete_signal() picked us to notify about the |
| 2957 | * group-wide signal. Other threads should be notified now to take |
| 2958 | * the shared signals in @which since we will not. |
| 2959 | */ |
| 2960 | static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) |
| 2961 | { |
| 2962 | sigset_t retarget; |
| 2963 | struct task_struct *t; |
| 2964 | |
| 2965 | sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); |
| 2966 | if (sigisemptyset(&retarget)) |
| 2967 | return; |
| 2968 | |
| 2969 | t = tsk; |
| 2970 | while_each_thread(tsk, t) { |
| 2971 | if (t->flags & PF_EXITING) |
| 2972 | continue; |
| 2973 | |
| 2974 | if (!has_pending_signals(&retarget, &t->blocked)) |
| 2975 | continue; |
| 2976 | /* Remove the signals this thread can handle. */ |
| 2977 | sigandsets(&retarget, &retarget, &t->blocked); |
| 2978 | |
| 2979 | if (!task_sigpending(t)) |
| 2980 | signal_wake_up(t, 0); |
| 2981 | |
| 2982 | if (sigisemptyset(&retarget)) |
| 2983 | break; |
| 2984 | } |
| 2985 | } |
| 2986 | |
| 2987 | void exit_signals(struct task_struct *tsk) |
| 2988 | { |
| 2989 | int group_stop = 0; |
| 2990 | sigset_t unblocked; |
| 2991 | |
| 2992 | /* |
| 2993 | * @tsk is about to have PF_EXITING set - lock out users which |
| 2994 | * expect stable threadgroup. |
| 2995 | */ |
| 2996 | cgroup_threadgroup_change_begin(tsk); |
| 2997 | |
| 2998 | if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) { |
| 2999 | sched_mm_cid_exit_signals(tsk); |
| 3000 | tsk->flags |= PF_EXITING; |
| 3001 | cgroup_threadgroup_change_end(tsk); |
| 3002 | return; |
| 3003 | } |
| 3004 | |
| 3005 | spin_lock_irq(&tsk->sighand->siglock); |
| 3006 | /* |
| 3007 | * From now this task is not visible for group-wide signals, |
| 3008 | * see wants_signal(), do_signal_stop(). |
| 3009 | */ |
| 3010 | sched_mm_cid_exit_signals(tsk); |
| 3011 | tsk->flags |= PF_EXITING; |
| 3012 | |
| 3013 | cgroup_threadgroup_change_end(tsk); |
| 3014 | |
| 3015 | if (!task_sigpending(tsk)) |
| 3016 | goto out; |
| 3017 | |
| 3018 | unblocked = tsk->blocked; |
| 3019 | signotset(&unblocked); |
| 3020 | retarget_shared_pending(tsk, &unblocked); |
| 3021 | |
| 3022 | if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) && |
| 3023 | task_participate_group_stop(tsk)) |
| 3024 | group_stop = CLD_STOPPED; |
| 3025 | out: |
| 3026 | spin_unlock_irq(&tsk->sighand->siglock); |
| 3027 | |
| 3028 | /* |
| 3029 | * If group stop has completed, deliver the notification. This |
| 3030 | * should always go to the real parent of the group leader. |
| 3031 | */ |
| 3032 | if (unlikely(group_stop)) { |
| 3033 | read_lock(&tasklist_lock); |
| 3034 | do_notify_parent_cldstop(tsk, false, group_stop); |
| 3035 | read_unlock(&tasklist_lock); |
| 3036 | } |
| 3037 | } |
| 3038 | |
| 3039 | /* |
| 3040 | * System call entry points. |
| 3041 | */ |
| 3042 | |
| 3043 | /** |
| 3044 | * sys_restart_syscall - restart a system call |
| 3045 | */ |
| 3046 | SYSCALL_DEFINE0(restart_syscall) |
| 3047 | { |
| 3048 | struct restart_block *restart = ¤t->restart_block; |
| 3049 | return restart->fn(restart); |
| 3050 | } |
| 3051 | |
| 3052 | long do_no_restart_syscall(struct restart_block *param) |
| 3053 | { |
| 3054 | return -EINTR; |
| 3055 | } |
| 3056 | |
| 3057 | static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset) |
| 3058 | { |
| 3059 | if (task_sigpending(tsk) && !thread_group_empty(tsk)) { |
| 3060 | sigset_t newblocked; |
| 3061 | /* A set of now blocked but previously unblocked signals. */ |
| 3062 | sigandnsets(&newblocked, newset, ¤t->blocked); |
| 3063 | retarget_shared_pending(tsk, &newblocked); |
| 3064 | } |
| 3065 | tsk->blocked = *newset; |
| 3066 | recalc_sigpending(); |
| 3067 | } |
| 3068 | |
| 3069 | /** |
| 3070 | * set_current_blocked - change current->blocked mask |
| 3071 | * @newset: new mask |
| 3072 | * |
| 3073 | * It is wrong to change ->blocked directly, this helper should be used |
| 3074 | * to ensure the process can't miss a shared signal we are going to block. |
| 3075 | */ |
| 3076 | void set_current_blocked(sigset_t *newset) |
| 3077 | { |
| 3078 | sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
| 3079 | __set_current_blocked(newset); |
| 3080 | } |
| 3081 | |
| 3082 | void __set_current_blocked(const sigset_t *newset) |
| 3083 | { |
| 3084 | struct task_struct *tsk = current; |
| 3085 | |
| 3086 | /* |
| 3087 | * In case the signal mask hasn't changed, there is nothing we need |
| 3088 | * to do. The current->blocked shouldn't be modified by other task. |
| 3089 | */ |
| 3090 | if (sigequalsets(&tsk->blocked, newset)) |
| 3091 | return; |
| 3092 | |
| 3093 | spin_lock_irq(&tsk->sighand->siglock); |
| 3094 | __set_task_blocked(tsk, newset); |
| 3095 | spin_unlock_irq(&tsk->sighand->siglock); |
| 3096 | } |
| 3097 | |
| 3098 | /* |
| 3099 | * This is also useful for kernel threads that want to temporarily |
| 3100 | * (or permanently) block certain signals. |
| 3101 | * |
| 3102 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel |
| 3103 | * interface happily blocks "unblockable" signals like SIGKILL |
| 3104 | * and friends. |
| 3105 | */ |
| 3106 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) |
| 3107 | { |
| 3108 | struct task_struct *tsk = current; |
| 3109 | sigset_t newset; |
| 3110 | |
| 3111 | /* Lockless, only current can change ->blocked, never from irq */ |
| 3112 | if (oldset) |
| 3113 | *oldset = tsk->blocked; |
| 3114 | |
| 3115 | switch (how) { |
| 3116 | case SIG_BLOCK: |
| 3117 | sigorsets(&newset, &tsk->blocked, set); |
| 3118 | break; |
| 3119 | case SIG_UNBLOCK: |
| 3120 | sigandnsets(&newset, &tsk->blocked, set); |
| 3121 | break; |
| 3122 | case SIG_SETMASK: |
| 3123 | newset = *set; |
| 3124 | break; |
| 3125 | default: |
| 3126 | return -EINVAL; |
| 3127 | } |
| 3128 | |
| 3129 | __set_current_blocked(&newset); |
| 3130 | return 0; |
| 3131 | } |
| 3132 | EXPORT_SYMBOL(sigprocmask); |
| 3133 | |
| 3134 | /* |
| 3135 | * The api helps set app-provided sigmasks. |
| 3136 | * |
| 3137 | * This is useful for syscalls such as ppoll, pselect, io_pgetevents and |
| 3138 | * epoll_pwait where a new sigmask is passed from userland for the syscalls. |
| 3139 | * |
| 3140 | * Note that it does set_restore_sigmask() in advance, so it must be always |
| 3141 | * paired with restore_saved_sigmask_unless() before return from syscall. |
| 3142 | */ |
| 3143 | int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize) |
| 3144 | { |
| 3145 | sigset_t kmask; |
| 3146 | |
| 3147 | if (!umask) |
| 3148 | return 0; |
| 3149 | if (sigsetsize != sizeof(sigset_t)) |
| 3150 | return -EINVAL; |
| 3151 | if (copy_from_user(&kmask, umask, sizeof(sigset_t))) |
| 3152 | return -EFAULT; |
| 3153 | |
| 3154 | set_restore_sigmask(); |
| 3155 | current->saved_sigmask = current->blocked; |
| 3156 | set_current_blocked(&kmask); |
| 3157 | |
| 3158 | return 0; |
| 3159 | } |
| 3160 | |
| 3161 | #ifdef CONFIG_COMPAT |
| 3162 | int set_compat_user_sigmask(const compat_sigset_t __user *umask, |
| 3163 | size_t sigsetsize) |
| 3164 | { |
| 3165 | sigset_t kmask; |
| 3166 | |
| 3167 | if (!umask) |
| 3168 | return 0; |
| 3169 | if (sigsetsize != sizeof(compat_sigset_t)) |
| 3170 | return -EINVAL; |
| 3171 | if (get_compat_sigset(&kmask, umask)) |
| 3172 | return -EFAULT; |
| 3173 | |
| 3174 | set_restore_sigmask(); |
| 3175 | current->saved_sigmask = current->blocked; |
| 3176 | set_current_blocked(&kmask); |
| 3177 | |
| 3178 | return 0; |
| 3179 | } |
| 3180 | #endif |
| 3181 | |
| 3182 | /** |
| 3183 | * sys_rt_sigprocmask - change the list of currently blocked signals |
| 3184 | * @how: whether to add, remove, or set signals |
| 3185 | * @nset: stores pending signals |
| 3186 | * @oset: previous value of signal mask if non-null |
| 3187 | * @sigsetsize: size of sigset_t type |
| 3188 | */ |
| 3189 | SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset, |
| 3190 | sigset_t __user *, oset, size_t, sigsetsize) |
| 3191 | { |
| 3192 | sigset_t old_set, new_set; |
| 3193 | int error; |
| 3194 | |
| 3195 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 3196 | if (sigsetsize != sizeof(sigset_t)) |
| 3197 | return -EINVAL; |
| 3198 | |
| 3199 | old_set = current->blocked; |
| 3200 | |
| 3201 | if (nset) { |
| 3202 | if (copy_from_user(&new_set, nset, sizeof(sigset_t))) |
| 3203 | return -EFAULT; |
| 3204 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
| 3205 | |
| 3206 | error = sigprocmask(how, &new_set, NULL); |
| 3207 | if (error) |
| 3208 | return error; |
| 3209 | } |
| 3210 | |
| 3211 | if (oset) { |
| 3212 | if (copy_to_user(oset, &old_set, sizeof(sigset_t))) |
| 3213 | return -EFAULT; |
| 3214 | } |
| 3215 | |
| 3216 | return 0; |
| 3217 | } |
| 3218 | |
| 3219 | #ifdef CONFIG_COMPAT |
| 3220 | COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, |
| 3221 | compat_sigset_t __user *, oset, compat_size_t, sigsetsize) |
| 3222 | { |
| 3223 | sigset_t old_set = current->blocked; |
| 3224 | |
| 3225 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 3226 | if (sigsetsize != sizeof(sigset_t)) |
| 3227 | return -EINVAL; |
| 3228 | |
| 3229 | if (nset) { |
| 3230 | sigset_t new_set; |
| 3231 | int error; |
| 3232 | if (get_compat_sigset(&new_set, nset)) |
| 3233 | return -EFAULT; |
| 3234 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
| 3235 | |
| 3236 | error = sigprocmask(how, &new_set, NULL); |
| 3237 | if (error) |
| 3238 | return error; |
| 3239 | } |
| 3240 | return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; |
| 3241 | } |
| 3242 | #endif |
| 3243 | |
| 3244 | static void do_sigpending(sigset_t *set) |
| 3245 | { |
| 3246 | spin_lock_irq(¤t->sighand->siglock); |
| 3247 | sigorsets(set, ¤t->pending.signal, |
| 3248 | ¤t->signal->shared_pending.signal); |
| 3249 | spin_unlock_irq(¤t->sighand->siglock); |
| 3250 | |
| 3251 | /* Outside the lock because only this thread touches it. */ |
| 3252 | sigandsets(set, ¤t->blocked, set); |
| 3253 | } |
| 3254 | |
| 3255 | /** |
| 3256 | * sys_rt_sigpending - examine a pending signal that has been raised |
| 3257 | * while blocked |
| 3258 | * @uset: stores pending signals |
| 3259 | * @sigsetsize: size of sigset_t type or larger |
| 3260 | */ |
| 3261 | SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) |
| 3262 | { |
| 3263 | sigset_t set; |
| 3264 | |
| 3265 | if (sigsetsize > sizeof(*uset)) |
| 3266 | return -EINVAL; |
| 3267 | |
| 3268 | do_sigpending(&set); |
| 3269 | |
| 3270 | if (copy_to_user(uset, &set, sigsetsize)) |
| 3271 | return -EFAULT; |
| 3272 | |
| 3273 | return 0; |
| 3274 | } |
| 3275 | |
| 3276 | #ifdef CONFIG_COMPAT |
| 3277 | COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, |
| 3278 | compat_size_t, sigsetsize) |
| 3279 | { |
| 3280 | sigset_t set; |
| 3281 | |
| 3282 | if (sigsetsize > sizeof(*uset)) |
| 3283 | return -EINVAL; |
| 3284 | |
| 3285 | do_sigpending(&set); |
| 3286 | |
| 3287 | return put_compat_sigset(uset, &set, sigsetsize); |
| 3288 | } |
| 3289 | #endif |
| 3290 | |
| 3291 | static const struct { |
| 3292 | unsigned char limit, layout; |
| 3293 | } sig_sicodes[] = { |
| 3294 | [SIGILL] = { NSIGILL, SIL_FAULT }, |
| 3295 | [SIGFPE] = { NSIGFPE, SIL_FAULT }, |
| 3296 | [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, |
| 3297 | [SIGBUS] = { NSIGBUS, SIL_FAULT }, |
| 3298 | [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, |
| 3299 | #if defined(SIGEMT) |
| 3300 | [SIGEMT] = { NSIGEMT, SIL_FAULT }, |
| 3301 | #endif |
| 3302 | [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, |
| 3303 | [SIGPOLL] = { NSIGPOLL, SIL_POLL }, |
| 3304 | [SIGSYS] = { NSIGSYS, SIL_SYS }, |
| 3305 | }; |
| 3306 | |
| 3307 | static bool known_siginfo_layout(unsigned sig, int si_code) |
| 3308 | { |
| 3309 | if (si_code == SI_KERNEL) |
| 3310 | return true; |
| 3311 | else if ((si_code > SI_USER)) { |
| 3312 | if (sig_specific_sicodes(sig)) { |
| 3313 | if (si_code <= sig_sicodes[sig].limit) |
| 3314 | return true; |
| 3315 | } |
| 3316 | else if (si_code <= NSIGPOLL) |
| 3317 | return true; |
| 3318 | } |
| 3319 | else if (si_code >= SI_DETHREAD) |
| 3320 | return true; |
| 3321 | else if (si_code == SI_ASYNCNL) |
| 3322 | return true; |
| 3323 | return false; |
| 3324 | } |
| 3325 | |
| 3326 | enum siginfo_layout siginfo_layout(unsigned sig, int si_code) |
| 3327 | { |
| 3328 | enum siginfo_layout layout = SIL_KILL; |
| 3329 | if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { |
| 3330 | if ((sig < ARRAY_SIZE(sig_sicodes)) && |
| 3331 | (si_code <= sig_sicodes[sig].limit)) { |
| 3332 | layout = sig_sicodes[sig].layout; |
| 3333 | /* Handle the exceptions */ |
| 3334 | if ((sig == SIGBUS) && |
| 3335 | (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO)) |
| 3336 | layout = SIL_FAULT_MCEERR; |
| 3337 | else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR)) |
| 3338 | layout = SIL_FAULT_BNDERR; |
| 3339 | #ifdef SEGV_PKUERR |
| 3340 | else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR)) |
| 3341 | layout = SIL_FAULT_PKUERR; |
| 3342 | #endif |
| 3343 | else if ((sig == SIGTRAP) && (si_code == TRAP_PERF)) |
| 3344 | layout = SIL_FAULT_PERF_EVENT; |
| 3345 | else if (IS_ENABLED(CONFIG_SPARC) && |
| 3346 | (sig == SIGILL) && (si_code == ILL_ILLTRP)) |
| 3347 | layout = SIL_FAULT_TRAPNO; |
| 3348 | else if (IS_ENABLED(CONFIG_ALPHA) && |
| 3349 | ((sig == SIGFPE) || |
| 3350 | ((sig == SIGTRAP) && (si_code == TRAP_UNK)))) |
| 3351 | layout = SIL_FAULT_TRAPNO; |
| 3352 | } |
| 3353 | else if (si_code <= NSIGPOLL) |
| 3354 | layout = SIL_POLL; |
| 3355 | } else { |
| 3356 | if (si_code == SI_TIMER) |
| 3357 | layout = SIL_TIMER; |
| 3358 | else if (si_code == SI_SIGIO) |
| 3359 | layout = SIL_POLL; |
| 3360 | else if (si_code < 0) |
| 3361 | layout = SIL_RT; |
| 3362 | } |
| 3363 | return layout; |
| 3364 | } |
| 3365 | |
| 3366 | static inline char __user *si_expansion(const siginfo_t __user *info) |
| 3367 | { |
| 3368 | return ((char __user *)info) + sizeof(struct kernel_siginfo); |
| 3369 | } |
| 3370 | |
| 3371 | int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from) |
| 3372 | { |
| 3373 | char __user *expansion = si_expansion(to); |
| 3374 | if (copy_to_user(to, from , sizeof(struct kernel_siginfo))) |
| 3375 | return -EFAULT; |
| 3376 | if (clear_user(expansion, SI_EXPANSION_SIZE)) |
| 3377 | return -EFAULT; |
| 3378 | return 0; |
| 3379 | } |
| 3380 | |
| 3381 | static int post_copy_siginfo_from_user(kernel_siginfo_t *info, |
| 3382 | const siginfo_t __user *from) |
| 3383 | { |
| 3384 | if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) { |
| 3385 | char __user *expansion = si_expansion(from); |
| 3386 | char buf[SI_EXPANSION_SIZE]; |
| 3387 | int i; |
| 3388 | /* |
| 3389 | * An unknown si_code might need more than |
| 3390 | * sizeof(struct kernel_siginfo) bytes. Verify all of the |
| 3391 | * extra bytes are 0. This guarantees copy_siginfo_to_user |
| 3392 | * will return this data to userspace exactly. |
| 3393 | */ |
| 3394 | if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE)) |
| 3395 | return -EFAULT; |
| 3396 | for (i = 0; i < SI_EXPANSION_SIZE; i++) { |
| 3397 | if (buf[i] != 0) |
| 3398 | return -E2BIG; |
| 3399 | } |
| 3400 | } |
| 3401 | return 0; |
| 3402 | } |
| 3403 | |
| 3404 | static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to, |
| 3405 | const siginfo_t __user *from) |
| 3406 | { |
| 3407 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) |
| 3408 | return -EFAULT; |
| 3409 | to->si_signo = signo; |
| 3410 | return post_copy_siginfo_from_user(to, from); |
| 3411 | } |
| 3412 | |
| 3413 | int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from) |
| 3414 | { |
| 3415 | if (copy_from_user(to, from, sizeof(struct kernel_siginfo))) |
| 3416 | return -EFAULT; |
| 3417 | return post_copy_siginfo_from_user(to, from); |
| 3418 | } |
| 3419 | |
| 3420 | #ifdef CONFIG_COMPAT |
| 3421 | /** |
| 3422 | * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo |
| 3423 | * @to: compat siginfo destination |
| 3424 | * @from: kernel siginfo source |
| 3425 | * |
| 3426 | * Note: This function does not work properly for the SIGCHLD on x32, but |
| 3427 | * fortunately it doesn't have to. The only valid callers for this function are |
| 3428 | * copy_siginfo_to_user32, which is overriden for x32 and the coredump code. |
| 3429 | * The latter does not care because SIGCHLD will never cause a coredump. |
| 3430 | */ |
| 3431 | void copy_siginfo_to_external32(struct compat_siginfo *to, |
| 3432 | const struct kernel_siginfo *from) |
| 3433 | { |
| 3434 | memset(to, 0, sizeof(*to)); |
| 3435 | |
| 3436 | to->si_signo = from->si_signo; |
| 3437 | to->si_errno = from->si_errno; |
| 3438 | to->si_code = from->si_code; |
| 3439 | switch(siginfo_layout(from->si_signo, from->si_code)) { |
| 3440 | case SIL_KILL: |
| 3441 | to->si_pid = from->si_pid; |
| 3442 | to->si_uid = from->si_uid; |
| 3443 | break; |
| 3444 | case SIL_TIMER: |
| 3445 | to->si_tid = from->si_tid; |
| 3446 | to->si_overrun = from->si_overrun; |
| 3447 | to->si_int = from->si_int; |
| 3448 | break; |
| 3449 | case SIL_POLL: |
| 3450 | to->si_band = from->si_band; |
| 3451 | to->si_fd = from->si_fd; |
| 3452 | break; |
| 3453 | case SIL_FAULT: |
| 3454 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3455 | break; |
| 3456 | case SIL_FAULT_TRAPNO: |
| 3457 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3458 | to->si_trapno = from->si_trapno; |
| 3459 | break; |
| 3460 | case SIL_FAULT_MCEERR: |
| 3461 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3462 | to->si_addr_lsb = from->si_addr_lsb; |
| 3463 | break; |
| 3464 | case SIL_FAULT_BNDERR: |
| 3465 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3466 | to->si_lower = ptr_to_compat(from->si_lower); |
| 3467 | to->si_upper = ptr_to_compat(from->si_upper); |
| 3468 | break; |
| 3469 | case SIL_FAULT_PKUERR: |
| 3470 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3471 | to->si_pkey = from->si_pkey; |
| 3472 | break; |
| 3473 | case SIL_FAULT_PERF_EVENT: |
| 3474 | to->si_addr = ptr_to_compat(from->si_addr); |
| 3475 | to->si_perf_data = from->si_perf_data; |
| 3476 | to->si_perf_type = from->si_perf_type; |
| 3477 | to->si_perf_flags = from->si_perf_flags; |
| 3478 | break; |
| 3479 | case SIL_CHLD: |
| 3480 | to->si_pid = from->si_pid; |
| 3481 | to->si_uid = from->si_uid; |
| 3482 | to->si_status = from->si_status; |
| 3483 | to->si_utime = from->si_utime; |
| 3484 | to->si_stime = from->si_stime; |
| 3485 | break; |
| 3486 | case SIL_RT: |
| 3487 | to->si_pid = from->si_pid; |
| 3488 | to->si_uid = from->si_uid; |
| 3489 | to->si_int = from->si_int; |
| 3490 | break; |
| 3491 | case SIL_SYS: |
| 3492 | to->si_call_addr = ptr_to_compat(from->si_call_addr); |
| 3493 | to->si_syscall = from->si_syscall; |
| 3494 | to->si_arch = from->si_arch; |
| 3495 | break; |
| 3496 | } |
| 3497 | } |
| 3498 | |
| 3499 | int __copy_siginfo_to_user32(struct compat_siginfo __user *to, |
| 3500 | const struct kernel_siginfo *from) |
| 3501 | { |
| 3502 | struct compat_siginfo new; |
| 3503 | |
| 3504 | copy_siginfo_to_external32(&new, from); |
| 3505 | if (copy_to_user(to, &new, sizeof(struct compat_siginfo))) |
| 3506 | return -EFAULT; |
| 3507 | return 0; |
| 3508 | } |
| 3509 | |
| 3510 | static int post_copy_siginfo_from_user32(kernel_siginfo_t *to, |
| 3511 | const struct compat_siginfo *from) |
| 3512 | { |
| 3513 | clear_siginfo(to); |
| 3514 | to->si_signo = from->si_signo; |
| 3515 | to->si_errno = from->si_errno; |
| 3516 | to->si_code = from->si_code; |
| 3517 | switch(siginfo_layout(from->si_signo, from->si_code)) { |
| 3518 | case SIL_KILL: |
| 3519 | to->si_pid = from->si_pid; |
| 3520 | to->si_uid = from->si_uid; |
| 3521 | break; |
| 3522 | case SIL_TIMER: |
| 3523 | to->si_tid = from->si_tid; |
| 3524 | to->si_overrun = from->si_overrun; |
| 3525 | to->si_int = from->si_int; |
| 3526 | break; |
| 3527 | case SIL_POLL: |
| 3528 | to->si_band = from->si_band; |
| 3529 | to->si_fd = from->si_fd; |
| 3530 | break; |
| 3531 | case SIL_FAULT: |
| 3532 | to->si_addr = compat_ptr(from->si_addr); |
| 3533 | break; |
| 3534 | case SIL_FAULT_TRAPNO: |
| 3535 | to->si_addr = compat_ptr(from->si_addr); |
| 3536 | to->si_trapno = from->si_trapno; |
| 3537 | break; |
| 3538 | case SIL_FAULT_MCEERR: |
| 3539 | to->si_addr = compat_ptr(from->si_addr); |
| 3540 | to->si_addr_lsb = from->si_addr_lsb; |
| 3541 | break; |
| 3542 | case SIL_FAULT_BNDERR: |
| 3543 | to->si_addr = compat_ptr(from->si_addr); |
| 3544 | to->si_lower = compat_ptr(from->si_lower); |
| 3545 | to->si_upper = compat_ptr(from->si_upper); |
| 3546 | break; |
| 3547 | case SIL_FAULT_PKUERR: |
| 3548 | to->si_addr = compat_ptr(from->si_addr); |
| 3549 | to->si_pkey = from->si_pkey; |
| 3550 | break; |
| 3551 | case SIL_FAULT_PERF_EVENT: |
| 3552 | to->si_addr = compat_ptr(from->si_addr); |
| 3553 | to->si_perf_data = from->si_perf_data; |
| 3554 | to->si_perf_type = from->si_perf_type; |
| 3555 | to->si_perf_flags = from->si_perf_flags; |
| 3556 | break; |
| 3557 | case SIL_CHLD: |
| 3558 | to->si_pid = from->si_pid; |
| 3559 | to->si_uid = from->si_uid; |
| 3560 | to->si_status = from->si_status; |
| 3561 | #ifdef CONFIG_X86_X32_ABI |
| 3562 | if (in_x32_syscall()) { |
| 3563 | to->si_utime = from->_sifields._sigchld_x32._utime; |
| 3564 | to->si_stime = from->_sifields._sigchld_x32._stime; |
| 3565 | } else |
| 3566 | #endif |
| 3567 | { |
| 3568 | to->si_utime = from->si_utime; |
| 3569 | to->si_stime = from->si_stime; |
| 3570 | } |
| 3571 | break; |
| 3572 | case SIL_RT: |
| 3573 | to->si_pid = from->si_pid; |
| 3574 | to->si_uid = from->si_uid; |
| 3575 | to->si_int = from->si_int; |
| 3576 | break; |
| 3577 | case SIL_SYS: |
| 3578 | to->si_call_addr = compat_ptr(from->si_call_addr); |
| 3579 | to->si_syscall = from->si_syscall; |
| 3580 | to->si_arch = from->si_arch; |
| 3581 | break; |
| 3582 | } |
| 3583 | return 0; |
| 3584 | } |
| 3585 | |
| 3586 | static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to, |
| 3587 | const struct compat_siginfo __user *ufrom) |
| 3588 | { |
| 3589 | struct compat_siginfo from; |
| 3590 | |
| 3591 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) |
| 3592 | return -EFAULT; |
| 3593 | |
| 3594 | from.si_signo = signo; |
| 3595 | return post_copy_siginfo_from_user32(to, &from); |
| 3596 | } |
| 3597 | |
| 3598 | int copy_siginfo_from_user32(struct kernel_siginfo *to, |
| 3599 | const struct compat_siginfo __user *ufrom) |
| 3600 | { |
| 3601 | struct compat_siginfo from; |
| 3602 | |
| 3603 | if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo))) |
| 3604 | return -EFAULT; |
| 3605 | |
| 3606 | return post_copy_siginfo_from_user32(to, &from); |
| 3607 | } |
| 3608 | #endif /* CONFIG_COMPAT */ |
| 3609 | |
| 3610 | /** |
| 3611 | * do_sigtimedwait - wait for queued signals specified in @which |
| 3612 | * @which: queued signals to wait for |
| 3613 | * @info: if non-null, the signal's siginfo is returned here |
| 3614 | * @ts: upper bound on process time suspension |
| 3615 | */ |
| 3616 | static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info, |
| 3617 | const struct timespec64 *ts) |
| 3618 | { |
| 3619 | ktime_t *to = NULL, timeout = KTIME_MAX; |
| 3620 | struct task_struct *tsk = current; |
| 3621 | sigset_t mask = *which; |
| 3622 | enum pid_type type; |
| 3623 | int sig, ret = 0; |
| 3624 | |
| 3625 | if (ts) { |
| 3626 | if (!timespec64_valid(ts)) |
| 3627 | return -EINVAL; |
| 3628 | timeout = timespec64_to_ktime(*ts); |
| 3629 | to = &timeout; |
| 3630 | } |
| 3631 | |
| 3632 | /* |
| 3633 | * Invert the set of allowed signals to get those we want to block. |
| 3634 | */ |
| 3635 | sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); |
| 3636 | signotset(&mask); |
| 3637 | |
| 3638 | spin_lock_irq(&tsk->sighand->siglock); |
| 3639 | sig = dequeue_signal(tsk, &mask, info, &type); |
| 3640 | if (!sig && timeout) { |
| 3641 | /* |
| 3642 | * None ready, temporarily unblock those we're interested |
| 3643 | * while we are sleeping in so that we'll be awakened when |
| 3644 | * they arrive. Unblocking is always fine, we can avoid |
| 3645 | * set_current_blocked(). |
| 3646 | */ |
| 3647 | tsk->real_blocked = tsk->blocked; |
| 3648 | sigandsets(&tsk->blocked, &tsk->blocked, &mask); |
| 3649 | recalc_sigpending(); |
| 3650 | spin_unlock_irq(&tsk->sighand->siglock); |
| 3651 | |
| 3652 | __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE); |
| 3653 | ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns, |
| 3654 | HRTIMER_MODE_REL); |
| 3655 | spin_lock_irq(&tsk->sighand->siglock); |
| 3656 | __set_task_blocked(tsk, &tsk->real_blocked); |
| 3657 | sigemptyset(&tsk->real_blocked); |
| 3658 | sig = dequeue_signal(tsk, &mask, info, &type); |
| 3659 | } |
| 3660 | spin_unlock_irq(&tsk->sighand->siglock); |
| 3661 | |
| 3662 | if (sig) |
| 3663 | return sig; |
| 3664 | return ret ? -EINTR : -EAGAIN; |
| 3665 | } |
| 3666 | |
| 3667 | /** |
| 3668 | * sys_rt_sigtimedwait - synchronously wait for queued signals specified |
| 3669 | * in @uthese |
| 3670 | * @uthese: queued signals to wait for |
| 3671 | * @uinfo: if non-null, the signal's siginfo is returned here |
| 3672 | * @uts: upper bound on process time suspension |
| 3673 | * @sigsetsize: size of sigset_t type |
| 3674 | */ |
| 3675 | SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese, |
| 3676 | siginfo_t __user *, uinfo, |
| 3677 | const struct __kernel_timespec __user *, uts, |
| 3678 | size_t, sigsetsize) |
| 3679 | { |
| 3680 | sigset_t these; |
| 3681 | struct timespec64 ts; |
| 3682 | kernel_siginfo_t info; |
| 3683 | int ret; |
| 3684 | |
| 3685 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 3686 | if (sigsetsize != sizeof(sigset_t)) |
| 3687 | return -EINVAL; |
| 3688 | |
| 3689 | if (copy_from_user(&these, uthese, sizeof(these))) |
| 3690 | return -EFAULT; |
| 3691 | |
| 3692 | if (uts) { |
| 3693 | if (get_timespec64(&ts, uts)) |
| 3694 | return -EFAULT; |
| 3695 | } |
| 3696 | |
| 3697 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
| 3698 | |
| 3699 | if (ret > 0 && uinfo) { |
| 3700 | if (copy_siginfo_to_user(uinfo, &info)) |
| 3701 | ret = -EFAULT; |
| 3702 | } |
| 3703 | |
| 3704 | return ret; |
| 3705 | } |
| 3706 | |
| 3707 | #ifdef CONFIG_COMPAT_32BIT_TIME |
| 3708 | SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese, |
| 3709 | siginfo_t __user *, uinfo, |
| 3710 | const struct old_timespec32 __user *, uts, |
| 3711 | size_t, sigsetsize) |
| 3712 | { |
| 3713 | sigset_t these; |
| 3714 | struct timespec64 ts; |
| 3715 | kernel_siginfo_t info; |
| 3716 | int ret; |
| 3717 | |
| 3718 | if (sigsetsize != sizeof(sigset_t)) |
| 3719 | return -EINVAL; |
| 3720 | |
| 3721 | if (copy_from_user(&these, uthese, sizeof(these))) |
| 3722 | return -EFAULT; |
| 3723 | |
| 3724 | if (uts) { |
| 3725 | if (get_old_timespec32(&ts, uts)) |
| 3726 | return -EFAULT; |
| 3727 | } |
| 3728 | |
| 3729 | ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL); |
| 3730 | |
| 3731 | if (ret > 0 && uinfo) { |
| 3732 | if (copy_siginfo_to_user(uinfo, &info)) |
| 3733 | ret = -EFAULT; |
| 3734 | } |
| 3735 | |
| 3736 | return ret; |
| 3737 | } |
| 3738 | #endif |
| 3739 | |
| 3740 | #ifdef CONFIG_COMPAT |
| 3741 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese, |
| 3742 | struct compat_siginfo __user *, uinfo, |
| 3743 | struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize) |
| 3744 | { |
| 3745 | sigset_t s; |
| 3746 | struct timespec64 t; |
| 3747 | kernel_siginfo_t info; |
| 3748 | long ret; |
| 3749 | |
| 3750 | if (sigsetsize != sizeof(sigset_t)) |
| 3751 | return -EINVAL; |
| 3752 | |
| 3753 | if (get_compat_sigset(&s, uthese)) |
| 3754 | return -EFAULT; |
| 3755 | |
| 3756 | if (uts) { |
| 3757 | if (get_timespec64(&t, uts)) |
| 3758 | return -EFAULT; |
| 3759 | } |
| 3760 | |
| 3761 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); |
| 3762 | |
| 3763 | if (ret > 0 && uinfo) { |
| 3764 | if (copy_siginfo_to_user32(uinfo, &info)) |
| 3765 | ret = -EFAULT; |
| 3766 | } |
| 3767 | |
| 3768 | return ret; |
| 3769 | } |
| 3770 | |
| 3771 | #ifdef CONFIG_COMPAT_32BIT_TIME |
| 3772 | COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese, |
| 3773 | struct compat_siginfo __user *, uinfo, |
| 3774 | struct old_timespec32 __user *, uts, compat_size_t, sigsetsize) |
| 3775 | { |
| 3776 | sigset_t s; |
| 3777 | struct timespec64 t; |
| 3778 | kernel_siginfo_t info; |
| 3779 | long ret; |
| 3780 | |
| 3781 | if (sigsetsize != sizeof(sigset_t)) |
| 3782 | return -EINVAL; |
| 3783 | |
| 3784 | if (get_compat_sigset(&s, uthese)) |
| 3785 | return -EFAULT; |
| 3786 | |
| 3787 | if (uts) { |
| 3788 | if (get_old_timespec32(&t, uts)) |
| 3789 | return -EFAULT; |
| 3790 | } |
| 3791 | |
| 3792 | ret = do_sigtimedwait(&s, &info, uts ? &t : NULL); |
| 3793 | |
| 3794 | if (ret > 0 && uinfo) { |
| 3795 | if (copy_siginfo_to_user32(uinfo, &info)) |
| 3796 | ret = -EFAULT; |
| 3797 | } |
| 3798 | |
| 3799 | return ret; |
| 3800 | } |
| 3801 | #endif |
| 3802 | #endif |
| 3803 | |
| 3804 | static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info) |
| 3805 | { |
| 3806 | clear_siginfo(info); |
| 3807 | info->si_signo = sig; |
| 3808 | info->si_errno = 0; |
| 3809 | info->si_code = SI_USER; |
| 3810 | info->si_pid = task_tgid_vnr(current); |
| 3811 | info->si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
| 3812 | } |
| 3813 | |
| 3814 | /** |
| 3815 | * sys_kill - send a signal to a process |
| 3816 | * @pid: the PID of the process |
| 3817 | * @sig: signal to be sent |
| 3818 | */ |
| 3819 | SYSCALL_DEFINE2(kill, pid_t, pid, int, sig) |
| 3820 | { |
| 3821 | struct kernel_siginfo info; |
| 3822 | |
| 3823 | prepare_kill_siginfo(sig, &info); |
| 3824 | |
| 3825 | return kill_something_info(sig, &info, pid); |
| 3826 | } |
| 3827 | |
| 3828 | /* |
| 3829 | * Verify that the signaler and signalee either are in the same pid namespace |
| 3830 | * or that the signaler's pid namespace is an ancestor of the signalee's pid |
| 3831 | * namespace. |
| 3832 | */ |
| 3833 | static bool access_pidfd_pidns(struct pid *pid) |
| 3834 | { |
| 3835 | struct pid_namespace *active = task_active_pid_ns(current); |
| 3836 | struct pid_namespace *p = ns_of_pid(pid); |
| 3837 | |
| 3838 | for (;;) { |
| 3839 | if (!p) |
| 3840 | return false; |
| 3841 | if (p == active) |
| 3842 | break; |
| 3843 | p = p->parent; |
| 3844 | } |
| 3845 | |
| 3846 | return true; |
| 3847 | } |
| 3848 | |
| 3849 | static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, |
| 3850 | siginfo_t __user *info) |
| 3851 | { |
| 3852 | #ifdef CONFIG_COMPAT |
| 3853 | /* |
| 3854 | * Avoid hooking up compat syscalls and instead handle necessary |
| 3855 | * conversions here. Note, this is a stop-gap measure and should not be |
| 3856 | * considered a generic solution. |
| 3857 | */ |
| 3858 | if (in_compat_syscall()) |
| 3859 | return copy_siginfo_from_user32( |
| 3860 | kinfo, (struct compat_siginfo __user *)info); |
| 3861 | #endif |
| 3862 | return copy_siginfo_from_user(kinfo, info); |
| 3863 | } |
| 3864 | |
| 3865 | static struct pid *pidfd_to_pid(const struct file *file) |
| 3866 | { |
| 3867 | struct pid *pid; |
| 3868 | |
| 3869 | pid = pidfd_pid(file); |
| 3870 | if (!IS_ERR(pid)) |
| 3871 | return pid; |
| 3872 | |
| 3873 | return tgid_pidfd_to_pid(file); |
| 3874 | } |
| 3875 | |
| 3876 | /** |
| 3877 | * sys_pidfd_send_signal - Signal a process through a pidfd |
| 3878 | * @pidfd: file descriptor of the process |
| 3879 | * @sig: signal to send |
| 3880 | * @info: signal info |
| 3881 | * @flags: future flags |
| 3882 | * |
| 3883 | * The syscall currently only signals via PIDTYPE_PID which covers |
| 3884 | * kill(<positive-pid>, <signal>. It does not signal threads or process |
| 3885 | * groups. |
| 3886 | * In order to extend the syscall to threads and process groups the @flags |
| 3887 | * argument should be used. In essence, the @flags argument will determine |
| 3888 | * what is signaled and not the file descriptor itself. Put in other words, |
| 3889 | * grouping is a property of the flags argument not a property of the file |
| 3890 | * descriptor. |
| 3891 | * |
| 3892 | * Return: 0 on success, negative errno on failure |
| 3893 | */ |
| 3894 | SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, |
| 3895 | siginfo_t __user *, info, unsigned int, flags) |
| 3896 | { |
| 3897 | int ret; |
| 3898 | struct fd f; |
| 3899 | struct pid *pid; |
| 3900 | kernel_siginfo_t kinfo; |
| 3901 | |
| 3902 | /* Enforce flags be set to 0 until we add an extension. */ |
| 3903 | if (flags) |
| 3904 | return -EINVAL; |
| 3905 | |
| 3906 | f = fdget(pidfd); |
| 3907 | if (!f.file) |
| 3908 | return -EBADF; |
| 3909 | |
| 3910 | /* Is this a pidfd? */ |
| 3911 | pid = pidfd_to_pid(f.file); |
| 3912 | if (IS_ERR(pid)) { |
| 3913 | ret = PTR_ERR(pid); |
| 3914 | goto err; |
| 3915 | } |
| 3916 | |
| 3917 | ret = -EINVAL; |
| 3918 | if (!access_pidfd_pidns(pid)) |
| 3919 | goto err; |
| 3920 | |
| 3921 | if (info) { |
| 3922 | ret = copy_siginfo_from_user_any(&kinfo, info); |
| 3923 | if (unlikely(ret)) |
| 3924 | goto err; |
| 3925 | |
| 3926 | ret = -EINVAL; |
| 3927 | if (unlikely(sig != kinfo.si_signo)) |
| 3928 | goto err; |
| 3929 | |
| 3930 | /* Only allow sending arbitrary signals to yourself. */ |
| 3931 | ret = -EPERM; |
| 3932 | if ((task_pid(current) != pid) && |
| 3933 | (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) |
| 3934 | goto err; |
| 3935 | } else { |
| 3936 | prepare_kill_siginfo(sig, &kinfo); |
| 3937 | } |
| 3938 | |
| 3939 | ret = kill_pid_info(sig, &kinfo, pid); |
| 3940 | |
| 3941 | err: |
| 3942 | fdput(f); |
| 3943 | return ret; |
| 3944 | } |
| 3945 | |
| 3946 | static int |
| 3947 | do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info) |
| 3948 | { |
| 3949 | struct task_struct *p; |
| 3950 | int error = -ESRCH; |
| 3951 | |
| 3952 | rcu_read_lock(); |
| 3953 | p = find_task_by_vpid(pid); |
| 3954 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
| 3955 | error = check_kill_permission(sig, info, p); |
| 3956 | /* |
| 3957 | * The null signal is a permissions and process existence |
| 3958 | * probe. No signal is actually delivered. |
| 3959 | */ |
| 3960 | if (!error && sig) { |
| 3961 | error = do_send_sig_info(sig, info, p, PIDTYPE_PID); |
| 3962 | /* |
| 3963 | * If lock_task_sighand() failed we pretend the task |
| 3964 | * dies after receiving the signal. The window is tiny, |
| 3965 | * and the signal is private anyway. |
| 3966 | */ |
| 3967 | if (unlikely(error == -ESRCH)) |
| 3968 | error = 0; |
| 3969 | } |
| 3970 | } |
| 3971 | rcu_read_unlock(); |
| 3972 | |
| 3973 | return error; |
| 3974 | } |
| 3975 | |
| 3976 | static int do_tkill(pid_t tgid, pid_t pid, int sig) |
| 3977 | { |
| 3978 | struct kernel_siginfo info; |
| 3979 | |
| 3980 | clear_siginfo(&info); |
| 3981 | info.si_signo = sig; |
| 3982 | info.si_errno = 0; |
| 3983 | info.si_code = SI_TKILL; |
| 3984 | info.si_pid = task_tgid_vnr(current); |
| 3985 | info.si_uid = from_kuid_munged(current_user_ns(), current_uid()); |
| 3986 | |
| 3987 | return do_send_specific(tgid, pid, sig, &info); |
| 3988 | } |
| 3989 | |
| 3990 | /** |
| 3991 | * sys_tgkill - send signal to one specific thread |
| 3992 | * @tgid: the thread group ID of the thread |
| 3993 | * @pid: the PID of the thread |
| 3994 | * @sig: signal to be sent |
| 3995 | * |
| 3996 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
| 3997 | * exists but it's not belonging to the target process anymore. This |
| 3998 | * method solves the problem of threads exiting and PIDs getting reused. |
| 3999 | */ |
| 4000 | SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig) |
| 4001 | { |
| 4002 | /* This is only valid for single tasks */ |
| 4003 | if (pid <= 0 || tgid <= 0) |
| 4004 | return -EINVAL; |
| 4005 | |
| 4006 | return do_tkill(tgid, pid, sig); |
| 4007 | } |
| 4008 | |
| 4009 | /** |
| 4010 | * sys_tkill - send signal to one specific task |
| 4011 | * @pid: the PID of the task |
| 4012 | * @sig: signal to be sent |
| 4013 | * |
| 4014 | * Send a signal to only one task, even if it's a CLONE_THREAD task. |
| 4015 | */ |
| 4016 | SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig) |
| 4017 | { |
| 4018 | /* This is only valid for single tasks */ |
| 4019 | if (pid <= 0) |
| 4020 | return -EINVAL; |
| 4021 | |
| 4022 | return do_tkill(0, pid, sig); |
| 4023 | } |
| 4024 | |
| 4025 | static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info) |
| 4026 | { |
| 4027 | /* Not even root can pretend to send signals from the kernel. |
| 4028 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
| 4029 | */ |
| 4030 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
| 4031 | (task_pid_vnr(current) != pid)) |
| 4032 | return -EPERM; |
| 4033 | |
| 4034 | /* POSIX.1b doesn't mention process groups. */ |
| 4035 | return kill_proc_info(sig, info, pid); |
| 4036 | } |
| 4037 | |
| 4038 | /** |
| 4039 | * sys_rt_sigqueueinfo - send signal information to a signal |
| 4040 | * @pid: the PID of the thread |
| 4041 | * @sig: signal to be sent |
| 4042 | * @uinfo: signal info to be sent |
| 4043 | */ |
| 4044 | SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, |
| 4045 | siginfo_t __user *, uinfo) |
| 4046 | { |
| 4047 | kernel_siginfo_t info; |
| 4048 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
| 4049 | if (unlikely(ret)) |
| 4050 | return ret; |
| 4051 | return do_rt_sigqueueinfo(pid, sig, &info); |
| 4052 | } |
| 4053 | |
| 4054 | #ifdef CONFIG_COMPAT |
| 4055 | COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo, |
| 4056 | compat_pid_t, pid, |
| 4057 | int, sig, |
| 4058 | struct compat_siginfo __user *, uinfo) |
| 4059 | { |
| 4060 | kernel_siginfo_t info; |
| 4061 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
| 4062 | if (unlikely(ret)) |
| 4063 | return ret; |
| 4064 | return do_rt_sigqueueinfo(pid, sig, &info); |
| 4065 | } |
| 4066 | #endif |
| 4067 | |
| 4068 | static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info) |
| 4069 | { |
| 4070 | /* This is only valid for single tasks */ |
| 4071 | if (pid <= 0 || tgid <= 0) |
| 4072 | return -EINVAL; |
| 4073 | |
| 4074 | /* Not even root can pretend to send signals from the kernel. |
| 4075 | * Nor can they impersonate a kill()/tgkill(), which adds source info. |
| 4076 | */ |
| 4077 | if ((info->si_code >= 0 || info->si_code == SI_TKILL) && |
| 4078 | (task_pid_vnr(current) != pid)) |
| 4079 | return -EPERM; |
| 4080 | |
| 4081 | return do_send_specific(tgid, pid, sig, info); |
| 4082 | } |
| 4083 | |
| 4084 | SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, |
| 4085 | siginfo_t __user *, uinfo) |
| 4086 | { |
| 4087 | kernel_siginfo_t info; |
| 4088 | int ret = __copy_siginfo_from_user(sig, &info, uinfo); |
| 4089 | if (unlikely(ret)) |
| 4090 | return ret; |
| 4091 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
| 4092 | } |
| 4093 | |
| 4094 | #ifdef CONFIG_COMPAT |
| 4095 | COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, |
| 4096 | compat_pid_t, tgid, |
| 4097 | compat_pid_t, pid, |
| 4098 | int, sig, |
| 4099 | struct compat_siginfo __user *, uinfo) |
| 4100 | { |
| 4101 | kernel_siginfo_t info; |
| 4102 | int ret = __copy_siginfo_from_user32(sig, &info, uinfo); |
| 4103 | if (unlikely(ret)) |
| 4104 | return ret; |
| 4105 | return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); |
| 4106 | } |
| 4107 | #endif |
| 4108 | |
| 4109 | /* |
| 4110 | * For kthreads only, must not be used if cloned with CLONE_SIGHAND |
| 4111 | */ |
| 4112 | void kernel_sigaction(int sig, __sighandler_t action) |
| 4113 | { |
| 4114 | spin_lock_irq(¤t->sighand->siglock); |
| 4115 | current->sighand->action[sig - 1].sa.sa_handler = action; |
| 4116 | if (action == SIG_IGN) { |
| 4117 | sigset_t mask; |
| 4118 | |
| 4119 | sigemptyset(&mask); |
| 4120 | sigaddset(&mask, sig); |
| 4121 | |
| 4122 | flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); |
| 4123 | flush_sigqueue_mask(&mask, ¤t->pending); |
| 4124 | recalc_sigpending(); |
| 4125 | } |
| 4126 | spin_unlock_irq(¤t->sighand->siglock); |
| 4127 | } |
| 4128 | EXPORT_SYMBOL(kernel_sigaction); |
| 4129 | |
| 4130 | void __weak sigaction_compat_abi(struct k_sigaction *act, |
| 4131 | struct k_sigaction *oact) |
| 4132 | { |
| 4133 | } |
| 4134 | |
| 4135 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
| 4136 | { |
| 4137 | struct task_struct *p = current, *t; |
| 4138 | struct k_sigaction *k; |
| 4139 | sigset_t mask; |
| 4140 | |
| 4141 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
| 4142 | return -EINVAL; |
| 4143 | |
| 4144 | k = &p->sighand->action[sig-1]; |
| 4145 | |
| 4146 | spin_lock_irq(&p->sighand->siglock); |
| 4147 | if (k->sa.sa_flags & SA_IMMUTABLE) { |
| 4148 | spin_unlock_irq(&p->sighand->siglock); |
| 4149 | return -EINVAL; |
| 4150 | } |
| 4151 | if (oact) |
| 4152 | *oact = *k; |
| 4153 | |
| 4154 | /* |
| 4155 | * Make sure that we never accidentally claim to support SA_UNSUPPORTED, |
| 4156 | * e.g. by having an architecture use the bit in their uapi. |
| 4157 | */ |
| 4158 | BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED); |
| 4159 | |
| 4160 | /* |
| 4161 | * Clear unknown flag bits in order to allow userspace to detect missing |
| 4162 | * support for flag bits and to allow the kernel to use non-uapi bits |
| 4163 | * internally. |
| 4164 | */ |
| 4165 | if (act) |
| 4166 | act->sa.sa_flags &= UAPI_SA_FLAGS; |
| 4167 | if (oact) |
| 4168 | oact->sa.sa_flags &= UAPI_SA_FLAGS; |
| 4169 | |
| 4170 | sigaction_compat_abi(act, oact); |
| 4171 | |
| 4172 | if (act) { |
| 4173 | sigdelsetmask(&act->sa.sa_mask, |
| 4174 | sigmask(SIGKILL) | sigmask(SIGSTOP)); |
| 4175 | *k = *act; |
| 4176 | /* |
| 4177 | * POSIX 3.3.1.3: |
| 4178 | * "Setting a signal action to SIG_IGN for a signal that is |
| 4179 | * pending shall cause the pending signal to be discarded, |
| 4180 | * whether or not it is blocked." |
| 4181 | * |
| 4182 | * "Setting a signal action to SIG_DFL for a signal that is |
| 4183 | * pending and whose default action is to ignore the signal |
| 4184 | * (for example, SIGCHLD), shall cause the pending signal to |
| 4185 | * be discarded, whether or not it is blocked" |
| 4186 | */ |
| 4187 | if (sig_handler_ignored(sig_handler(p, sig), sig)) { |
| 4188 | sigemptyset(&mask); |
| 4189 | sigaddset(&mask, sig); |
| 4190 | flush_sigqueue_mask(&mask, &p->signal->shared_pending); |
| 4191 | for_each_thread(p, t) |
| 4192 | flush_sigqueue_mask(&mask, &t->pending); |
| 4193 | } |
| 4194 | } |
| 4195 | |
| 4196 | spin_unlock_irq(&p->sighand->siglock); |
| 4197 | return 0; |
| 4198 | } |
| 4199 | |
| 4200 | #ifdef CONFIG_DYNAMIC_SIGFRAME |
| 4201 | static inline void sigaltstack_lock(void) |
| 4202 | __acquires(¤t->sighand->siglock) |
| 4203 | { |
| 4204 | spin_lock_irq(¤t->sighand->siglock); |
| 4205 | } |
| 4206 | |
| 4207 | static inline void sigaltstack_unlock(void) |
| 4208 | __releases(¤t->sighand->siglock) |
| 4209 | { |
| 4210 | spin_unlock_irq(¤t->sighand->siglock); |
| 4211 | } |
| 4212 | #else |
| 4213 | static inline void sigaltstack_lock(void) { } |
| 4214 | static inline void sigaltstack_unlock(void) { } |
| 4215 | #endif |
| 4216 | |
| 4217 | static int |
| 4218 | do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, |
| 4219 | size_t min_ss_size) |
| 4220 | { |
| 4221 | struct task_struct *t = current; |
| 4222 | int ret = 0; |
| 4223 | |
| 4224 | if (oss) { |
| 4225 | memset(oss, 0, sizeof(stack_t)); |
| 4226 | oss->ss_sp = (void __user *) t->sas_ss_sp; |
| 4227 | oss->ss_size = t->sas_ss_size; |
| 4228 | oss->ss_flags = sas_ss_flags(sp) | |
| 4229 | (current->sas_ss_flags & SS_FLAG_BITS); |
| 4230 | } |
| 4231 | |
| 4232 | if (ss) { |
| 4233 | void __user *ss_sp = ss->ss_sp; |
| 4234 | size_t ss_size = ss->ss_size; |
| 4235 | unsigned ss_flags = ss->ss_flags; |
| 4236 | int ss_mode; |
| 4237 | |
| 4238 | if (unlikely(on_sig_stack(sp))) |
| 4239 | return -EPERM; |
| 4240 | |
| 4241 | ss_mode = ss_flags & ~SS_FLAG_BITS; |
| 4242 | if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK && |
| 4243 | ss_mode != 0)) |
| 4244 | return -EINVAL; |
| 4245 | |
| 4246 | /* |
| 4247 | * Return before taking any locks if no actual |
| 4248 | * sigaltstack changes were requested. |
| 4249 | */ |
| 4250 | if (t->sas_ss_sp == (unsigned long)ss_sp && |
| 4251 | t->sas_ss_size == ss_size && |
| 4252 | t->sas_ss_flags == ss_flags) |
| 4253 | return 0; |
| 4254 | |
| 4255 | sigaltstack_lock(); |
| 4256 | if (ss_mode == SS_DISABLE) { |
| 4257 | ss_size = 0; |
| 4258 | ss_sp = NULL; |
| 4259 | } else { |
| 4260 | if (unlikely(ss_size < min_ss_size)) |
| 4261 | ret = -ENOMEM; |
| 4262 | if (!sigaltstack_size_valid(ss_size)) |
| 4263 | ret = -ENOMEM; |
| 4264 | } |
| 4265 | if (!ret) { |
| 4266 | t->sas_ss_sp = (unsigned long) ss_sp; |
| 4267 | t->sas_ss_size = ss_size; |
| 4268 | t->sas_ss_flags = ss_flags; |
| 4269 | } |
| 4270 | sigaltstack_unlock(); |
| 4271 | } |
| 4272 | return ret; |
| 4273 | } |
| 4274 | |
| 4275 | SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) |
| 4276 | { |
| 4277 | stack_t new, old; |
| 4278 | int err; |
| 4279 | if (uss && copy_from_user(&new, uss, sizeof(stack_t))) |
| 4280 | return -EFAULT; |
| 4281 | err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL, |
| 4282 | current_user_stack_pointer(), |
| 4283 | MINSIGSTKSZ); |
| 4284 | if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t))) |
| 4285 | err = -EFAULT; |
| 4286 | return err; |
| 4287 | } |
| 4288 | |
| 4289 | int restore_altstack(const stack_t __user *uss) |
| 4290 | { |
| 4291 | stack_t new; |
| 4292 | if (copy_from_user(&new, uss, sizeof(stack_t))) |
| 4293 | return -EFAULT; |
| 4294 | (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(), |
| 4295 | MINSIGSTKSZ); |
| 4296 | /* squash all but EFAULT for now */ |
| 4297 | return 0; |
| 4298 | } |
| 4299 | |
| 4300 | int __save_altstack(stack_t __user *uss, unsigned long sp) |
| 4301 | { |
| 4302 | struct task_struct *t = current; |
| 4303 | int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) | |
| 4304 | __put_user(t->sas_ss_flags, &uss->ss_flags) | |
| 4305 | __put_user(t->sas_ss_size, &uss->ss_size); |
| 4306 | return err; |
| 4307 | } |
| 4308 | |
| 4309 | #ifdef CONFIG_COMPAT |
| 4310 | static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr, |
| 4311 | compat_stack_t __user *uoss_ptr) |
| 4312 | { |
| 4313 | stack_t uss, uoss; |
| 4314 | int ret; |
| 4315 | |
| 4316 | if (uss_ptr) { |
| 4317 | compat_stack_t uss32; |
| 4318 | if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t))) |
| 4319 | return -EFAULT; |
| 4320 | uss.ss_sp = compat_ptr(uss32.ss_sp); |
| 4321 | uss.ss_flags = uss32.ss_flags; |
| 4322 | uss.ss_size = uss32.ss_size; |
| 4323 | } |
| 4324 | ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, |
| 4325 | compat_user_stack_pointer(), |
| 4326 | COMPAT_MINSIGSTKSZ); |
| 4327 | if (ret >= 0 && uoss_ptr) { |
| 4328 | compat_stack_t old; |
| 4329 | memset(&old, 0, sizeof(old)); |
| 4330 | old.ss_sp = ptr_to_compat(uoss.ss_sp); |
| 4331 | old.ss_flags = uoss.ss_flags; |
| 4332 | old.ss_size = uoss.ss_size; |
| 4333 | if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t))) |
| 4334 | ret = -EFAULT; |
| 4335 | } |
| 4336 | return ret; |
| 4337 | } |
| 4338 | |
| 4339 | COMPAT_SYSCALL_DEFINE2(sigaltstack, |
| 4340 | const compat_stack_t __user *, uss_ptr, |
| 4341 | compat_stack_t __user *, uoss_ptr) |
| 4342 | { |
| 4343 | return do_compat_sigaltstack(uss_ptr, uoss_ptr); |
| 4344 | } |
| 4345 | |
| 4346 | int compat_restore_altstack(const compat_stack_t __user *uss) |
| 4347 | { |
| 4348 | int err = do_compat_sigaltstack(uss, NULL); |
| 4349 | /* squash all but -EFAULT for now */ |
| 4350 | return err == -EFAULT ? err : 0; |
| 4351 | } |
| 4352 | |
| 4353 | int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp) |
| 4354 | { |
| 4355 | int err; |
| 4356 | struct task_struct *t = current; |
| 4357 | err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), |
| 4358 | &uss->ss_sp) | |
| 4359 | __put_user(t->sas_ss_flags, &uss->ss_flags) | |
| 4360 | __put_user(t->sas_ss_size, &uss->ss_size); |
| 4361 | return err; |
| 4362 | } |
| 4363 | #endif |
| 4364 | |
| 4365 | #ifdef __ARCH_WANT_SYS_SIGPENDING |
| 4366 | |
| 4367 | /** |
| 4368 | * sys_sigpending - examine pending signals |
| 4369 | * @uset: where mask of pending signal is returned |
| 4370 | */ |
| 4371 | SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset) |
| 4372 | { |
| 4373 | sigset_t set; |
| 4374 | |
| 4375 | if (sizeof(old_sigset_t) > sizeof(*uset)) |
| 4376 | return -EINVAL; |
| 4377 | |
| 4378 | do_sigpending(&set); |
| 4379 | |
| 4380 | if (copy_to_user(uset, &set, sizeof(old_sigset_t))) |
| 4381 | return -EFAULT; |
| 4382 | |
| 4383 | return 0; |
| 4384 | } |
| 4385 | |
| 4386 | #ifdef CONFIG_COMPAT |
| 4387 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) |
| 4388 | { |
| 4389 | sigset_t set; |
| 4390 | |
| 4391 | do_sigpending(&set); |
| 4392 | |
| 4393 | return put_user(set.sig[0], set32); |
| 4394 | } |
| 4395 | #endif |
| 4396 | |
| 4397 | #endif |
| 4398 | |
| 4399 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK |
| 4400 | /** |
| 4401 | * sys_sigprocmask - examine and change blocked signals |
| 4402 | * @how: whether to add, remove, or set signals |
| 4403 | * @nset: signals to add or remove (if non-null) |
| 4404 | * @oset: previous value of signal mask if non-null |
| 4405 | * |
| 4406 | * Some platforms have their own version with special arguments; |
| 4407 | * others support only sys_rt_sigprocmask. |
| 4408 | */ |
| 4409 | |
| 4410 | SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset, |
| 4411 | old_sigset_t __user *, oset) |
| 4412 | { |
| 4413 | old_sigset_t old_set, new_set; |
| 4414 | sigset_t new_blocked; |
| 4415 | |
| 4416 | old_set = current->blocked.sig[0]; |
| 4417 | |
| 4418 | if (nset) { |
| 4419 | if (copy_from_user(&new_set, nset, sizeof(*nset))) |
| 4420 | return -EFAULT; |
| 4421 | |
| 4422 | new_blocked = current->blocked; |
| 4423 | |
| 4424 | switch (how) { |
| 4425 | case SIG_BLOCK: |
| 4426 | sigaddsetmask(&new_blocked, new_set); |
| 4427 | break; |
| 4428 | case SIG_UNBLOCK: |
| 4429 | sigdelsetmask(&new_blocked, new_set); |
| 4430 | break; |
| 4431 | case SIG_SETMASK: |
| 4432 | new_blocked.sig[0] = new_set; |
| 4433 | break; |
| 4434 | default: |
| 4435 | return -EINVAL; |
| 4436 | } |
| 4437 | |
| 4438 | set_current_blocked(&new_blocked); |
| 4439 | } |
| 4440 | |
| 4441 | if (oset) { |
| 4442 | if (copy_to_user(oset, &old_set, sizeof(*oset))) |
| 4443 | return -EFAULT; |
| 4444 | } |
| 4445 | |
| 4446 | return 0; |
| 4447 | } |
| 4448 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ |
| 4449 | |
| 4450 | #ifndef CONFIG_ODD_RT_SIGACTION |
| 4451 | /** |
| 4452 | * sys_rt_sigaction - alter an action taken by a process |
| 4453 | * @sig: signal to be sent |
| 4454 | * @act: new sigaction |
| 4455 | * @oact: used to save the previous sigaction |
| 4456 | * @sigsetsize: size of sigset_t type |
| 4457 | */ |
| 4458 | SYSCALL_DEFINE4(rt_sigaction, int, sig, |
| 4459 | const struct sigaction __user *, act, |
| 4460 | struct sigaction __user *, oact, |
| 4461 | size_t, sigsetsize) |
| 4462 | { |
| 4463 | struct k_sigaction new_sa, old_sa; |
| 4464 | int ret; |
| 4465 | |
| 4466 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 4467 | if (sigsetsize != sizeof(sigset_t)) |
| 4468 | return -EINVAL; |
| 4469 | |
| 4470 | if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) |
| 4471 | return -EFAULT; |
| 4472 | |
| 4473 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); |
| 4474 | if (ret) |
| 4475 | return ret; |
| 4476 | |
| 4477 | if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) |
| 4478 | return -EFAULT; |
| 4479 | |
| 4480 | return 0; |
| 4481 | } |
| 4482 | #ifdef CONFIG_COMPAT |
| 4483 | COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig, |
| 4484 | const struct compat_sigaction __user *, act, |
| 4485 | struct compat_sigaction __user *, oact, |
| 4486 | compat_size_t, sigsetsize) |
| 4487 | { |
| 4488 | struct k_sigaction new_ka, old_ka; |
| 4489 | #ifdef __ARCH_HAS_SA_RESTORER |
| 4490 | compat_uptr_t restorer; |
| 4491 | #endif |
| 4492 | int ret; |
| 4493 | |
| 4494 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 4495 | if (sigsetsize != sizeof(compat_sigset_t)) |
| 4496 | return -EINVAL; |
| 4497 | |
| 4498 | if (act) { |
| 4499 | compat_uptr_t handler; |
| 4500 | ret = get_user(handler, &act->sa_handler); |
| 4501 | new_ka.sa.sa_handler = compat_ptr(handler); |
| 4502 | #ifdef __ARCH_HAS_SA_RESTORER |
| 4503 | ret |= get_user(restorer, &act->sa_restorer); |
| 4504 | new_ka.sa.sa_restorer = compat_ptr(restorer); |
| 4505 | #endif |
| 4506 | ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask); |
| 4507 | ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags); |
| 4508 | if (ret) |
| 4509 | return -EFAULT; |
| 4510 | } |
| 4511 | |
| 4512 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
| 4513 | if (!ret && oact) { |
| 4514 | ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), |
| 4515 | &oact->sa_handler); |
| 4516 | ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask, |
| 4517 | sizeof(oact->sa_mask)); |
| 4518 | ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags); |
| 4519 | #ifdef __ARCH_HAS_SA_RESTORER |
| 4520 | ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), |
| 4521 | &oact->sa_restorer); |
| 4522 | #endif |
| 4523 | } |
| 4524 | return ret; |
| 4525 | } |
| 4526 | #endif |
| 4527 | #endif /* !CONFIG_ODD_RT_SIGACTION */ |
| 4528 | |
| 4529 | #ifdef CONFIG_OLD_SIGACTION |
| 4530 | SYSCALL_DEFINE3(sigaction, int, sig, |
| 4531 | const struct old_sigaction __user *, act, |
| 4532 | struct old_sigaction __user *, oact) |
| 4533 | { |
| 4534 | struct k_sigaction new_ka, old_ka; |
| 4535 | int ret; |
| 4536 | |
| 4537 | if (act) { |
| 4538 | old_sigset_t mask; |
| 4539 | if (!access_ok(act, sizeof(*act)) || |
| 4540 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || |
| 4541 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || |
| 4542 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || |
| 4543 | __get_user(mask, &act->sa_mask)) |
| 4544 | return -EFAULT; |
| 4545 | #ifdef __ARCH_HAS_KA_RESTORER |
| 4546 | new_ka.ka_restorer = NULL; |
| 4547 | #endif |
| 4548 | siginitset(&new_ka.sa.sa_mask, mask); |
| 4549 | } |
| 4550 | |
| 4551 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
| 4552 | |
| 4553 | if (!ret && oact) { |
| 4554 | if (!access_ok(oact, sizeof(*oact)) || |
| 4555 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || |
| 4556 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || |
| 4557 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || |
| 4558 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) |
| 4559 | return -EFAULT; |
| 4560 | } |
| 4561 | |
| 4562 | return ret; |
| 4563 | } |
| 4564 | #endif |
| 4565 | #ifdef CONFIG_COMPAT_OLD_SIGACTION |
| 4566 | COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, |
| 4567 | const struct compat_old_sigaction __user *, act, |
| 4568 | struct compat_old_sigaction __user *, oact) |
| 4569 | { |
| 4570 | struct k_sigaction new_ka, old_ka; |
| 4571 | int ret; |
| 4572 | compat_old_sigset_t mask; |
| 4573 | compat_uptr_t handler, restorer; |
| 4574 | |
| 4575 | if (act) { |
| 4576 | if (!access_ok(act, sizeof(*act)) || |
| 4577 | __get_user(handler, &act->sa_handler) || |
| 4578 | __get_user(restorer, &act->sa_restorer) || |
| 4579 | __get_user(new_ka.sa.sa_flags, &act->sa_flags) || |
| 4580 | __get_user(mask, &act->sa_mask)) |
| 4581 | return -EFAULT; |
| 4582 | |
| 4583 | #ifdef __ARCH_HAS_KA_RESTORER |
| 4584 | new_ka.ka_restorer = NULL; |
| 4585 | #endif |
| 4586 | new_ka.sa.sa_handler = compat_ptr(handler); |
| 4587 | new_ka.sa.sa_restorer = compat_ptr(restorer); |
| 4588 | siginitset(&new_ka.sa.sa_mask, mask); |
| 4589 | } |
| 4590 | |
| 4591 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); |
| 4592 | |
| 4593 | if (!ret && oact) { |
| 4594 | if (!access_ok(oact, sizeof(*oact)) || |
| 4595 | __put_user(ptr_to_compat(old_ka.sa.sa_handler), |
| 4596 | &oact->sa_handler) || |
| 4597 | __put_user(ptr_to_compat(old_ka.sa.sa_restorer), |
| 4598 | &oact->sa_restorer) || |
| 4599 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || |
| 4600 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) |
| 4601 | return -EFAULT; |
| 4602 | } |
| 4603 | return ret; |
| 4604 | } |
| 4605 | #endif |
| 4606 | |
| 4607 | #ifdef CONFIG_SGETMASK_SYSCALL |
| 4608 | |
| 4609 | /* |
| 4610 | * For backwards compatibility. Functionality superseded by sigprocmask. |
| 4611 | */ |
| 4612 | SYSCALL_DEFINE0(sgetmask) |
| 4613 | { |
| 4614 | /* SMP safe */ |
| 4615 | return current->blocked.sig[0]; |
| 4616 | } |
| 4617 | |
| 4618 | SYSCALL_DEFINE1(ssetmask, int, newmask) |
| 4619 | { |
| 4620 | int old = current->blocked.sig[0]; |
| 4621 | sigset_t newset; |
| 4622 | |
| 4623 | siginitset(&newset, newmask); |
| 4624 | set_current_blocked(&newset); |
| 4625 | |
| 4626 | return old; |
| 4627 | } |
| 4628 | #endif /* CONFIG_SGETMASK_SYSCALL */ |
| 4629 | |
| 4630 | #ifdef __ARCH_WANT_SYS_SIGNAL |
| 4631 | /* |
| 4632 | * For backwards compatibility. Functionality superseded by sigaction. |
| 4633 | */ |
| 4634 | SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler) |
| 4635 | { |
| 4636 | struct k_sigaction new_sa, old_sa; |
| 4637 | int ret; |
| 4638 | |
| 4639 | new_sa.sa.sa_handler = handler; |
| 4640 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; |
| 4641 | sigemptyset(&new_sa.sa.sa_mask); |
| 4642 | |
| 4643 | ret = do_sigaction(sig, &new_sa, &old_sa); |
| 4644 | |
| 4645 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; |
| 4646 | } |
| 4647 | #endif /* __ARCH_WANT_SYS_SIGNAL */ |
| 4648 | |
| 4649 | #ifdef __ARCH_WANT_SYS_PAUSE |
| 4650 | |
| 4651 | SYSCALL_DEFINE0(pause) |
| 4652 | { |
| 4653 | while (!signal_pending(current)) { |
| 4654 | __set_current_state(TASK_INTERRUPTIBLE); |
| 4655 | schedule(); |
| 4656 | } |
| 4657 | return -ERESTARTNOHAND; |
| 4658 | } |
| 4659 | |
| 4660 | #endif |
| 4661 | |
| 4662 | static int sigsuspend(sigset_t *set) |
| 4663 | { |
| 4664 | current->saved_sigmask = current->blocked; |
| 4665 | set_current_blocked(set); |
| 4666 | |
| 4667 | while (!signal_pending(current)) { |
| 4668 | __set_current_state(TASK_INTERRUPTIBLE); |
| 4669 | schedule(); |
| 4670 | } |
| 4671 | set_restore_sigmask(); |
| 4672 | return -ERESTARTNOHAND; |
| 4673 | } |
| 4674 | |
| 4675 | /** |
| 4676 | * sys_rt_sigsuspend - replace the signal mask for a value with the |
| 4677 | * @unewset value until a signal is received |
| 4678 | * @unewset: new signal mask value |
| 4679 | * @sigsetsize: size of sigset_t type |
| 4680 | */ |
| 4681 | SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize) |
| 4682 | { |
| 4683 | sigset_t newset; |
| 4684 | |
| 4685 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 4686 | if (sigsetsize != sizeof(sigset_t)) |
| 4687 | return -EINVAL; |
| 4688 | |
| 4689 | if (copy_from_user(&newset, unewset, sizeof(newset))) |
| 4690 | return -EFAULT; |
| 4691 | return sigsuspend(&newset); |
| 4692 | } |
| 4693 | |
| 4694 | #ifdef CONFIG_COMPAT |
| 4695 | COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize) |
| 4696 | { |
| 4697 | sigset_t newset; |
| 4698 | |
| 4699 | /* XXX: Don't preclude handling different sized sigset_t's. */ |
| 4700 | if (sigsetsize != sizeof(sigset_t)) |
| 4701 | return -EINVAL; |
| 4702 | |
| 4703 | if (get_compat_sigset(&newset, unewset)) |
| 4704 | return -EFAULT; |
| 4705 | return sigsuspend(&newset); |
| 4706 | } |
| 4707 | #endif |
| 4708 | |
| 4709 | #ifdef CONFIG_OLD_SIGSUSPEND |
| 4710 | SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask) |
| 4711 | { |
| 4712 | sigset_t blocked; |
| 4713 | siginitset(&blocked, mask); |
| 4714 | return sigsuspend(&blocked); |
| 4715 | } |
| 4716 | #endif |
| 4717 | #ifdef CONFIG_OLD_SIGSUSPEND3 |
| 4718 | SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) |
| 4719 | { |
| 4720 | sigset_t blocked; |
| 4721 | siginitset(&blocked, mask); |
| 4722 | return sigsuspend(&blocked); |
| 4723 | } |
| 4724 | #endif |
| 4725 | |
| 4726 | __weak const char *arch_vma_name(struct vm_area_struct *vma) |
| 4727 | { |
| 4728 | return NULL; |
| 4729 | } |
| 4730 | |
| 4731 | static inline void siginfo_buildtime_checks(void) |
| 4732 | { |
| 4733 | BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE); |
| 4734 | |
| 4735 | /* Verify the offsets in the two siginfos match */ |
| 4736 | #define CHECK_OFFSET(field) \ |
| 4737 | BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field)) |
| 4738 | |
| 4739 | /* kill */ |
| 4740 | CHECK_OFFSET(si_pid); |
| 4741 | CHECK_OFFSET(si_uid); |
| 4742 | |
| 4743 | /* timer */ |
| 4744 | CHECK_OFFSET(si_tid); |
| 4745 | CHECK_OFFSET(si_overrun); |
| 4746 | CHECK_OFFSET(si_value); |
| 4747 | |
| 4748 | /* rt */ |
| 4749 | CHECK_OFFSET(si_pid); |
| 4750 | CHECK_OFFSET(si_uid); |
| 4751 | CHECK_OFFSET(si_value); |
| 4752 | |
| 4753 | /* sigchld */ |
| 4754 | CHECK_OFFSET(si_pid); |
| 4755 | CHECK_OFFSET(si_uid); |
| 4756 | CHECK_OFFSET(si_status); |
| 4757 | CHECK_OFFSET(si_utime); |
| 4758 | CHECK_OFFSET(si_stime); |
| 4759 | |
| 4760 | /* sigfault */ |
| 4761 | CHECK_OFFSET(si_addr); |
| 4762 | CHECK_OFFSET(si_trapno); |
| 4763 | CHECK_OFFSET(si_addr_lsb); |
| 4764 | CHECK_OFFSET(si_lower); |
| 4765 | CHECK_OFFSET(si_upper); |
| 4766 | CHECK_OFFSET(si_pkey); |
| 4767 | CHECK_OFFSET(si_perf_data); |
| 4768 | CHECK_OFFSET(si_perf_type); |
| 4769 | CHECK_OFFSET(si_perf_flags); |
| 4770 | |
| 4771 | /* sigpoll */ |
| 4772 | CHECK_OFFSET(si_band); |
| 4773 | CHECK_OFFSET(si_fd); |
| 4774 | |
| 4775 | /* sigsys */ |
| 4776 | CHECK_OFFSET(si_call_addr); |
| 4777 | CHECK_OFFSET(si_syscall); |
| 4778 | CHECK_OFFSET(si_arch); |
| 4779 | #undef CHECK_OFFSET |
| 4780 | |
| 4781 | /* usb asyncio */ |
| 4782 | BUILD_BUG_ON(offsetof(struct siginfo, si_pid) != |
| 4783 | offsetof(struct siginfo, si_addr)); |
| 4784 | if (sizeof(int) == sizeof(void __user *)) { |
| 4785 | BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) != |
| 4786 | sizeof(void __user *)); |
| 4787 | } else { |
| 4788 | BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) + |
| 4789 | sizeof_field(struct siginfo, si_uid)) != |
| 4790 | sizeof(void __user *)); |
| 4791 | BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) != |
| 4792 | offsetof(struct siginfo, si_uid)); |
| 4793 | } |
| 4794 | #ifdef CONFIG_COMPAT |
| 4795 | BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) != |
| 4796 | offsetof(struct compat_siginfo, si_addr)); |
| 4797 | BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != |
| 4798 | sizeof(compat_uptr_t)); |
| 4799 | BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) != |
| 4800 | sizeof_field(struct siginfo, si_pid)); |
| 4801 | #endif |
| 4802 | } |
| 4803 | |
| 4804 | #if defined(CONFIG_SYSCTL) |
| 4805 | static struct ctl_table signal_debug_table[] = { |
| 4806 | #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE |
| 4807 | { |
| 4808 | .procname = "exception-trace", |
| 4809 | .data = &show_unhandled_signals, |
| 4810 | .maxlen = sizeof(int), |
| 4811 | .mode = 0644, |
| 4812 | .proc_handler = proc_dointvec |
| 4813 | }, |
| 4814 | #endif |
| 4815 | { } |
| 4816 | }; |
| 4817 | |
| 4818 | static int __init init_signal_sysctls(void) |
| 4819 | { |
| 4820 | register_sysctl_init("debug", signal_debug_table); |
| 4821 | return 0; |
| 4822 | } |
| 4823 | early_initcall(init_signal_sysctls); |
| 4824 | #endif /* CONFIG_SYSCTL */ |
| 4825 | |
| 4826 | void __init signals_init(void) |
| 4827 | { |
| 4828 | siginfo_buildtime_checks(); |
| 4829 | |
| 4830 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT); |
| 4831 | } |
| 4832 | |
| 4833 | #ifdef CONFIG_KGDB_KDB |
| 4834 | #include <linux/kdb.h> |
| 4835 | /* |
| 4836 | * kdb_send_sig - Allows kdb to send signals without exposing |
| 4837 | * signal internals. This function checks if the required locks are |
| 4838 | * available before calling the main signal code, to avoid kdb |
| 4839 | * deadlocks. |
| 4840 | */ |
| 4841 | void kdb_send_sig(struct task_struct *t, int sig) |
| 4842 | { |
| 4843 | static struct task_struct *kdb_prev_t; |
| 4844 | int new_t, ret; |
| 4845 | if (!spin_trylock(&t->sighand->siglock)) { |
| 4846 | kdb_printf("Can't do kill command now.\n" |
| 4847 | "The sigmask lock is held somewhere else in " |
| 4848 | "kernel, try again later\n"); |
| 4849 | return; |
| 4850 | } |
| 4851 | new_t = kdb_prev_t != t; |
| 4852 | kdb_prev_t = t; |
| 4853 | if (!task_is_running(t) && new_t) { |
| 4854 | spin_unlock(&t->sighand->siglock); |
| 4855 | kdb_printf("Process is not RUNNING, sending a signal from " |
| 4856 | "kdb risks deadlock\n" |
| 4857 | "on the run queue locks. " |
| 4858 | "The signal has _not_ been sent.\n" |
| 4859 | "Reissue the kill command if you want to risk " |
| 4860 | "the deadlock.\n"); |
| 4861 | return; |
| 4862 | } |
| 4863 | ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID); |
| 4864 | spin_unlock(&t->sighand->siglock); |
| 4865 | if (ret) |
| 4866 | kdb_printf("Fail to deliver Signal %d to process %d.\n", |
| 4867 | sig, t->pid); |
| 4868 | else |
| 4869 | kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid); |
| 4870 | } |
| 4871 | #endif /* CONFIG_KGDB_KDB */ |