Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/ptrace.c | |
3 | * | |
4 | * (C) Copyright 1999 Linus Torvalds | |
5 | * | |
6 | * Common interfaces for "ptrace()" which we do not want | |
7 | * to continually duplicate across every architecture. | |
8 | */ | |
9 | ||
c59ede7b | 10 | #include <linux/capability.h> |
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/sched.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/highmem.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/smp_lock.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/security.h> | |
7ed20e1a | 20 | #include <linux/signal.h> |
a5cb013d | 21 | #include <linux/audit.h> |
b488893a | 22 | #include <linux/pid_namespace.h> |
f17d30a8 | 23 | #include <linux/syscalls.h> |
3a709703 | 24 | #include <linux/uaccess.h> |
1da177e4 | 25 | |
bf53de90 | 26 | |
1da177e4 LT |
27 | /* |
28 | * ptrace a task: make the debugger its new parent and | |
29 | * move it to the ptrace list. | |
30 | * | |
31 | * Must be called with the tasklist lock write-held. | |
32 | */ | |
36c8b586 | 33 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) |
1da177e4 | 34 | { |
f470021a RM |
35 | BUG_ON(!list_empty(&child->ptrace_entry)); |
36 | list_add(&child->ptrace_entry, &new_parent->ptraced); | |
1da177e4 | 37 | child->parent = new_parent; |
1da177e4 | 38 | } |
3a709703 | 39 | |
1da177e4 LT |
40 | /* |
41 | * Turn a tracing stop into a normal stop now, since with no tracer there | |
42 | * would be no way to wake it up with SIGCONT or SIGKILL. If there was a | |
43 | * signal sent that would resume the child, but didn't because it was in | |
44 | * TASK_TRACED, resume it now. | |
45 | * Requires that irqs be disabled. | |
46 | */ | |
b747c8c1 | 47 | static void ptrace_untrace(struct task_struct *child) |
1da177e4 LT |
48 | { |
49 | spin_lock(&child->sighand->siglock); | |
6618a3e2 | 50 | if (task_is_traced(child)) { |
1ee11844 ON |
51 | /* |
52 | * If the group stop is completed or in progress, | |
53 | * this thread was already counted as stopped. | |
54 | */ | |
55 | if (child->signal->flags & SIGNAL_STOP_STOPPED || | |
56 | child->signal->group_stop_count) | |
d9ae90ac | 57 | __set_task_state(child, TASK_STOPPED); |
1ee11844 | 58 | else |
1da177e4 | 59 | signal_wake_up(child, 1); |
1da177e4 LT |
60 | } |
61 | spin_unlock(&child->sighand->siglock); | |
62 | } | |
63 | ||
64 | /* | |
65 | * unptrace a task: move it back to its original parent and | |
66 | * remove it from the ptrace list. | |
67 | * | |
68 | * Must be called with the tasklist lock write-held. | |
69 | */ | |
36c8b586 | 70 | void __ptrace_unlink(struct task_struct *child) |
1da177e4 | 71 | { |
5ecfbae0 ON |
72 | BUG_ON(!child->ptrace); |
73 | ||
1da177e4 | 74 | child->ptrace = 0; |
f470021a RM |
75 | child->parent = child->real_parent; |
76 | list_del_init(&child->ptrace_entry); | |
1da177e4 | 77 | |
bf53de90 | 78 | arch_ptrace_untrace(child); |
6618a3e2 | 79 | if (task_is_traced(child)) |
e57a5059 | 80 | ptrace_untrace(child); |
1da177e4 LT |
81 | } |
82 | ||
83 | /* | |
84 | * Check that we have indeed attached to the thing.. | |
85 | */ | |
86 | int ptrace_check_attach(struct task_struct *child, int kill) | |
87 | { | |
88 | int ret = -ESRCH; | |
89 | ||
90 | /* | |
91 | * We take the read lock around doing both checks to close a | |
92 | * possible race where someone else was tracing our child and | |
93 | * detached between these two checks. After this locked check, | |
94 | * we are sure that this is our traced child and that can only | |
95 | * be changed by us so it's not changing right after this. | |
96 | */ | |
97 | read_lock(&tasklist_lock); | |
c0c0b649 | 98 | if ((child->ptrace & PT_PTRACED) && child->parent == current) { |
1da177e4 | 99 | ret = 0; |
c0c0b649 ON |
100 | /* |
101 | * child->sighand can't be NULL, release_task() | |
102 | * does ptrace_unlink() before __exit_signal(). | |
103 | */ | |
1da177e4 | 104 | spin_lock_irq(&child->sighand->siglock); |
d9ae90ac | 105 | if (task_is_stopped(child)) |
1da177e4 | 106 | child->state = TASK_TRACED; |
d9ae90ac | 107 | else if (!task_is_traced(child) && !kill) |
1da177e4 | 108 | ret = -ESRCH; |
1da177e4 LT |
109 | spin_unlock_irq(&child->sighand->siglock); |
110 | } | |
111 | read_unlock(&tasklist_lock); | |
112 | ||
d9ae90ac | 113 | if (!ret && !kill) |
85ba2d86 | 114 | ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; |
1da177e4 LT |
115 | |
116 | /* All systems go.. */ | |
117 | return ret; | |
118 | } | |
119 | ||
006ebb40 | 120 | int __ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be | 121 | { |
c69e8d9c | 122 | const struct cred *cred = current_cred(), *tcred; |
b6dff3ec | 123 | |
df26c40e EB |
124 | /* May we inspect the given task? |
125 | * This check is used both for attaching with ptrace | |
126 | * and for allowing access to sensitive information in /proc. | |
127 | * | |
128 | * ptrace_attach denies several cases that /proc allows | |
129 | * because setting up the necessary parent/child relationship | |
130 | * or halting the specified task is impossible. | |
131 | */ | |
132 | int dumpable = 0; | |
133 | /* Don't let security modules deny introspection */ | |
134 | if (task == current) | |
135 | return 0; | |
c69e8d9c DH |
136 | rcu_read_lock(); |
137 | tcred = __task_cred(task); | |
138 | if ((cred->uid != tcred->euid || | |
139 | cred->uid != tcred->suid || | |
140 | cred->uid != tcred->uid || | |
141 | cred->gid != tcred->egid || | |
142 | cred->gid != tcred->sgid || | |
143 | cred->gid != tcred->gid) && | |
144 | !capable(CAP_SYS_PTRACE)) { | |
145 | rcu_read_unlock(); | |
ab8d11be | 146 | return -EPERM; |
c69e8d9c DH |
147 | } |
148 | rcu_read_unlock(); | |
ab8d11be | 149 | smp_rmb(); |
df26c40e | 150 | if (task->mm) |
6c5d5238 | 151 | dumpable = get_dumpable(task->mm); |
df26c40e | 152 | if (!dumpable && !capable(CAP_SYS_PTRACE)) |
ab8d11be MS |
153 | return -EPERM; |
154 | ||
5cd9c58f | 155 | return security_ptrace_may_access(task, mode); |
ab8d11be MS |
156 | } |
157 | ||
006ebb40 | 158 | bool ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be MS |
159 | { |
160 | int err; | |
161 | task_lock(task); | |
006ebb40 | 162 | err = __ptrace_may_access(task, mode); |
ab8d11be | 163 | task_unlock(task); |
3a709703 | 164 | return !err; |
ab8d11be MS |
165 | } |
166 | ||
1da177e4 LT |
167 | int ptrace_attach(struct task_struct *task) |
168 | { | |
169 | int retval; | |
6175ecfe | 170 | unsigned long flags; |
f5b40e36 | 171 | |
a5cb013d AV |
172 | audit_ptrace(task); |
173 | ||
1da177e4 | 174 | retval = -EPERM; |
b79b7ba9 ON |
175 | if (unlikely(task->flags & PF_KTHREAD)) |
176 | goto out; | |
bac0abd6 | 177 | if (same_thread_group(task, current)) |
f5b40e36 LT |
178 | goto out; |
179 | ||
5e751e99 DH |
180 | /* Protect the target's credential calculations against our |
181 | * interference; SUID, SGID and LSM creds get determined differently | |
182 | * under ptrace. | |
d84f4f99 | 183 | */ |
5e751e99 | 184 | retval = mutex_lock_interruptible(&task->cred_guard_mutex); |
d84f4f99 DH |
185 | if (retval < 0) |
186 | goto out; | |
f358166a LT |
187 | repeat: |
188 | /* | |
189 | * Nasty, nasty. | |
190 | * | |
191 | * We want to hold both the task-lock and the | |
192 | * tasklist_lock for writing at the same time. | |
193 | * But that's against the rules (tasklist_lock | |
194 | * is taken for reading by interrupts on other | |
195 | * cpu's that may have task_lock). | |
196 | */ | |
f5b40e36 | 197 | task_lock(task); |
6175ecfe | 198 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { |
f358166a LT |
199 | task_unlock(task); |
200 | do { | |
201 | cpu_relax(); | |
202 | } while (!write_can_lock(&tasklist_lock)); | |
203 | goto repeat; | |
204 | } | |
f5b40e36 | 205 | |
006ebb40 | 206 | retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); |
1da177e4 LT |
207 | if (retval) |
208 | goto bad; | |
209 | ||
b79b7ba9 ON |
210 | retval = -EPERM; |
211 | if (unlikely(task->exit_state)) | |
212 | goto bad; | |
213 | if (task->ptrace & PT_PTRACED) | |
214 | goto bad; | |
215 | ||
6b39c7bf | 216 | task->ptrace |= PT_PTRACED; |
1da177e4 LT |
217 | if (capable(CAP_SYS_PTRACE)) |
218 | task->ptrace |= PT_PTRACE_CAP; | |
1da177e4 | 219 | |
1da177e4 | 220 | __ptrace_link(task, current); |
33e9fc7d | 221 | send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); |
b79b7ba9 ON |
222 | |
223 | retval = 0; | |
1da177e4 | 224 | bad: |
6175ecfe | 225 | write_unlock_irqrestore(&tasklist_lock, flags); |
1da177e4 | 226 | task_unlock(task); |
5e751e99 | 227 | mutex_unlock(&task->cred_guard_mutex); |
f5b40e36 | 228 | out: |
1da177e4 LT |
229 | return retval; |
230 | } | |
231 | ||
39c626ae ON |
232 | /* |
233 | * Called with irqs disabled, returns true if childs should reap themselves. | |
234 | */ | |
235 | static int ignoring_children(struct sighand_struct *sigh) | |
236 | { | |
237 | int ret; | |
238 | spin_lock(&sigh->siglock); | |
239 | ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || | |
240 | (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); | |
241 | spin_unlock(&sigh->siglock); | |
242 | return ret; | |
243 | } | |
244 | ||
245 | /* | |
246 | * Called with tasklist_lock held for writing. | |
247 | * Unlink a traced task, and clean it up if it was a traced zombie. | |
248 | * Return true if it needs to be reaped with release_task(). | |
249 | * (We can't call release_task() here because we already hold tasklist_lock.) | |
250 | * | |
251 | * If it's a zombie, our attachedness prevented normal parent notification | |
252 | * or self-reaping. Do notification now if it would have happened earlier. | |
253 | * If it should reap itself, return true. | |
254 | * | |
255 | * If it's our own child, there is no notification to do. | |
256 | * But if our normal children self-reap, then this child | |
257 | * was prevented by ptrace and we must reap it now. | |
258 | */ | |
259 | static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) | |
260 | { | |
261 | __ptrace_unlink(p); | |
262 | ||
263 | if (p->exit_state == EXIT_ZOMBIE) { | |
264 | if (!task_detached(p) && thread_group_empty(p)) { | |
265 | if (!same_thread_group(p->real_parent, tracer)) | |
266 | do_notify_parent(p, p->exit_signal); | |
267 | else if (ignoring_children(tracer->sighand)) | |
268 | p->exit_signal = -1; | |
269 | } | |
270 | if (task_detached(p)) { | |
271 | /* Mark it as in the process of being reaped. */ | |
272 | p->exit_state = EXIT_DEAD; | |
273 | return true; | |
274 | } | |
275 | } | |
276 | ||
277 | return false; | |
278 | } | |
279 | ||
1da177e4 LT |
280 | int ptrace_detach(struct task_struct *child, unsigned int data) |
281 | { | |
39c626ae | 282 | bool dead = false; |
4576145c | 283 | |
7ed20e1a | 284 | if (!valid_signal(data)) |
5ecfbae0 | 285 | return -EIO; |
1da177e4 LT |
286 | |
287 | /* Architecture-specific hardware disable .. */ | |
288 | ptrace_disable(child); | |
7d941432 | 289 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
1da177e4 | 290 | |
95c3eb76 | 291 | write_lock_irq(&tasklist_lock); |
39c626ae ON |
292 | /* |
293 | * This child can be already killed. Make sure de_thread() or | |
294 | * our sub-thread doing do_wait() didn't do release_task() yet. | |
295 | */ | |
95c3eb76 ON |
296 | if (child->ptrace) { |
297 | child->exit_code = data; | |
4576145c | 298 | dead = __ptrace_detach(current, child); |
edaba2c5 ON |
299 | if (!child->exit_state) |
300 | wake_up_process(child); | |
95c3eb76 | 301 | } |
1da177e4 LT |
302 | write_unlock_irq(&tasklist_lock); |
303 | ||
4576145c ON |
304 | if (unlikely(dead)) |
305 | release_task(child); | |
306 | ||
1da177e4 LT |
307 | return 0; |
308 | } | |
309 | ||
39c626ae ON |
310 | /* |
311 | * Detach all tasks we were using ptrace on. | |
312 | */ | |
313 | void exit_ptrace(struct task_struct *tracer) | |
314 | { | |
315 | struct task_struct *p, *n; | |
316 | LIST_HEAD(ptrace_dead); | |
317 | ||
318 | write_lock_irq(&tasklist_lock); | |
319 | list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { | |
320 | if (__ptrace_detach(tracer, p)) | |
321 | list_add(&p->ptrace_entry, &ptrace_dead); | |
322 | } | |
323 | write_unlock_irq(&tasklist_lock); | |
324 | ||
325 | BUG_ON(!list_empty(&tracer->ptraced)); | |
326 | ||
327 | list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { | |
328 | list_del_init(&p->ptrace_entry); | |
329 | release_task(p); | |
330 | } | |
331 | } | |
332 | ||
1da177e4 LT |
333 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) |
334 | { | |
335 | int copied = 0; | |
336 | ||
337 | while (len > 0) { | |
338 | char buf[128]; | |
339 | int this_len, retval; | |
340 | ||
341 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
342 | retval = access_process_vm(tsk, src, buf, this_len, 0); | |
343 | if (!retval) { | |
344 | if (copied) | |
345 | break; | |
346 | return -EIO; | |
347 | } | |
348 | if (copy_to_user(dst, buf, retval)) | |
349 | return -EFAULT; | |
350 | copied += retval; | |
351 | src += retval; | |
352 | dst += retval; | |
3a709703 | 353 | len -= retval; |
1da177e4 LT |
354 | } |
355 | return copied; | |
356 | } | |
357 | ||
358 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) | |
359 | { | |
360 | int copied = 0; | |
361 | ||
362 | while (len > 0) { | |
363 | char buf[128]; | |
364 | int this_len, retval; | |
365 | ||
366 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
367 | if (copy_from_user(buf, src, this_len)) | |
368 | return -EFAULT; | |
369 | retval = access_process_vm(tsk, dst, buf, this_len, 1); | |
370 | if (!retval) { | |
371 | if (copied) | |
372 | break; | |
373 | return -EIO; | |
374 | } | |
375 | copied += retval; | |
376 | src += retval; | |
377 | dst += retval; | |
3a709703 | 378 | len -= retval; |
1da177e4 LT |
379 | } |
380 | return copied; | |
381 | } | |
382 | ||
383 | static int ptrace_setoptions(struct task_struct *child, long data) | |
384 | { | |
385 | child->ptrace &= ~PT_TRACE_MASK; | |
386 | ||
387 | if (data & PTRACE_O_TRACESYSGOOD) | |
388 | child->ptrace |= PT_TRACESYSGOOD; | |
389 | ||
390 | if (data & PTRACE_O_TRACEFORK) | |
391 | child->ptrace |= PT_TRACE_FORK; | |
392 | ||
393 | if (data & PTRACE_O_TRACEVFORK) | |
394 | child->ptrace |= PT_TRACE_VFORK; | |
395 | ||
396 | if (data & PTRACE_O_TRACECLONE) | |
397 | child->ptrace |= PT_TRACE_CLONE; | |
398 | ||
399 | if (data & PTRACE_O_TRACEEXEC) | |
400 | child->ptrace |= PT_TRACE_EXEC; | |
401 | ||
402 | if (data & PTRACE_O_TRACEVFORKDONE) | |
403 | child->ptrace |= PT_TRACE_VFORK_DONE; | |
404 | ||
405 | if (data & PTRACE_O_TRACEEXIT) | |
406 | child->ptrace |= PT_TRACE_EXIT; | |
407 | ||
408 | return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; | |
409 | } | |
410 | ||
e16b2781 | 411 | static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) |
1da177e4 | 412 | { |
1da177e4 LT |
413 | int error = -ESRCH; |
414 | ||
415 | read_lock(&tasklist_lock); | |
416 | if (likely(child->sighand != NULL)) { | |
417 | error = -EINVAL; | |
418 | spin_lock_irq(&child->sighand->siglock); | |
419 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 420 | *info = *child->last_siginfo; |
1da177e4 LT |
421 | error = 0; |
422 | } | |
423 | spin_unlock_irq(&child->sighand->siglock); | |
424 | } | |
425 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
426 | return error; |
427 | } | |
428 | ||
e16b2781 | 429 | static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) |
1da177e4 | 430 | { |
1da177e4 LT |
431 | int error = -ESRCH; |
432 | ||
1da177e4 LT |
433 | read_lock(&tasklist_lock); |
434 | if (likely(child->sighand != NULL)) { | |
435 | error = -EINVAL; | |
436 | spin_lock_irq(&child->sighand->siglock); | |
437 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 438 | *child->last_siginfo = *info; |
1da177e4 LT |
439 | error = 0; |
440 | } | |
441 | spin_unlock_irq(&child->sighand->siglock); | |
442 | } | |
443 | read_unlock(&tasklist_lock); | |
444 | return error; | |
445 | } | |
446 | ||
36df29d7 RM |
447 | |
448 | #ifdef PTRACE_SINGLESTEP | |
449 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) | |
450 | #else | |
451 | #define is_singlestep(request) 0 | |
452 | #endif | |
453 | ||
5b88abbf RM |
454 | #ifdef PTRACE_SINGLEBLOCK |
455 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) | |
456 | #else | |
457 | #define is_singleblock(request) 0 | |
458 | #endif | |
459 | ||
36df29d7 RM |
460 | #ifdef PTRACE_SYSEMU |
461 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) | |
462 | #else | |
463 | #define is_sysemu_singlestep(request) 0 | |
464 | #endif | |
465 | ||
466 | static int ptrace_resume(struct task_struct *child, long request, long data) | |
467 | { | |
468 | if (!valid_signal(data)) | |
469 | return -EIO; | |
470 | ||
471 | if (request == PTRACE_SYSCALL) | |
472 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
473 | else | |
474 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
475 | ||
476 | #ifdef TIF_SYSCALL_EMU | |
477 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) | |
478 | set_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
479 | else | |
480 | clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
481 | #endif | |
482 | ||
5b88abbf RM |
483 | if (is_singleblock(request)) { |
484 | if (unlikely(!arch_has_block_step())) | |
485 | return -EIO; | |
486 | user_enable_block_step(child); | |
487 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { | |
36df29d7 RM |
488 | if (unlikely(!arch_has_single_step())) |
489 | return -EIO; | |
490 | user_enable_single_step(child); | |
3a709703 | 491 | } else { |
36df29d7 | 492 | user_disable_single_step(child); |
3a709703 | 493 | } |
36df29d7 RM |
494 | |
495 | child->exit_code = data; | |
496 | wake_up_process(child); | |
497 | ||
498 | return 0; | |
499 | } | |
500 | ||
1da177e4 LT |
501 | int ptrace_request(struct task_struct *child, long request, |
502 | long addr, long data) | |
503 | { | |
504 | int ret = -EIO; | |
e16b2781 | 505 | siginfo_t siginfo; |
1da177e4 LT |
506 | |
507 | switch (request) { | |
16c3e389 RM |
508 | case PTRACE_PEEKTEXT: |
509 | case PTRACE_PEEKDATA: | |
510 | return generic_ptrace_peekdata(child, addr, data); | |
511 | case PTRACE_POKETEXT: | |
512 | case PTRACE_POKEDATA: | |
513 | return generic_ptrace_pokedata(child, addr, data); | |
514 | ||
1da177e4 LT |
515 | #ifdef PTRACE_OLDSETOPTIONS |
516 | case PTRACE_OLDSETOPTIONS: | |
517 | #endif | |
518 | case PTRACE_SETOPTIONS: | |
519 | ret = ptrace_setoptions(child, data); | |
520 | break; | |
521 | case PTRACE_GETEVENTMSG: | |
522 | ret = put_user(child->ptrace_message, (unsigned long __user *) data); | |
523 | break; | |
e16b2781 | 524 | |
1da177e4 | 525 | case PTRACE_GETSIGINFO: |
e16b2781 RM |
526 | ret = ptrace_getsiginfo(child, &siginfo); |
527 | if (!ret) | |
528 | ret = copy_siginfo_to_user((siginfo_t __user *) data, | |
529 | &siginfo); | |
1da177e4 | 530 | break; |
e16b2781 | 531 | |
1da177e4 | 532 | case PTRACE_SETSIGINFO: |
e16b2781 RM |
533 | if (copy_from_user(&siginfo, (siginfo_t __user *) data, |
534 | sizeof siginfo)) | |
535 | ret = -EFAULT; | |
536 | else | |
537 | ret = ptrace_setsiginfo(child, &siginfo); | |
1da177e4 | 538 | break; |
e16b2781 | 539 | |
1bcf5482 AD |
540 | case PTRACE_DETACH: /* detach a process that was attached. */ |
541 | ret = ptrace_detach(child, data); | |
542 | break; | |
36df29d7 RM |
543 | |
544 | #ifdef PTRACE_SINGLESTEP | |
545 | case PTRACE_SINGLESTEP: | |
546 | #endif | |
5b88abbf RM |
547 | #ifdef PTRACE_SINGLEBLOCK |
548 | case PTRACE_SINGLEBLOCK: | |
549 | #endif | |
36df29d7 RM |
550 | #ifdef PTRACE_SYSEMU |
551 | case PTRACE_SYSEMU: | |
552 | case PTRACE_SYSEMU_SINGLESTEP: | |
553 | #endif | |
554 | case PTRACE_SYSCALL: | |
555 | case PTRACE_CONT: | |
556 | return ptrace_resume(child, request, data); | |
557 | ||
558 | case PTRACE_KILL: | |
559 | if (child->exit_state) /* already dead */ | |
560 | return 0; | |
561 | return ptrace_resume(child, request, SIGKILL); | |
562 | ||
1da177e4 LT |
563 | default: |
564 | break; | |
565 | } | |
566 | ||
567 | return ret; | |
568 | } | |
481bed45 | 569 | |
6b9c7ed8 CH |
570 | /** |
571 | * ptrace_traceme -- helper for PTRACE_TRACEME | |
572 | * | |
573 | * Performs checks and sets PT_PTRACED. | |
574 | * Should be used by all ptrace implementations for PTRACE_TRACEME. | |
575 | */ | |
576 | int ptrace_traceme(void) | |
481bed45 | 577 | { |
f5b40e36 | 578 | int ret = -EPERM; |
481bed45 CH |
579 | |
580 | /* | |
6b9c7ed8 CH |
581 | * Are we already being traced? |
582 | */ | |
f470021a | 583 | repeat: |
f5b40e36 LT |
584 | task_lock(current); |
585 | if (!(current->ptrace & PT_PTRACED)) { | |
f470021a RM |
586 | /* |
587 | * See ptrace_attach() comments about the locking here. | |
588 | */ | |
589 | unsigned long flags; | |
590 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { | |
591 | task_unlock(current); | |
592 | do { | |
593 | cpu_relax(); | |
594 | } while (!write_can_lock(&tasklist_lock)); | |
595 | goto repeat; | |
596 | } | |
597 | ||
5cd9c58f | 598 | ret = security_ptrace_traceme(current->parent); |
f470021a | 599 | |
f5b40e36 | 600 | /* |
f1671f6d ON |
601 | * Check PF_EXITING to ensure ->real_parent has not passed |
602 | * exit_ptrace(). Otherwise we don't report the error but | |
603 | * pretend ->real_parent untraces us right after return. | |
f5b40e36 | 604 | */ |
f1671f6d | 605 | if (!ret && !(current->real_parent->flags & PF_EXITING)) { |
f5b40e36 | 606 | current->ptrace |= PT_PTRACED; |
f470021a RM |
607 | __ptrace_link(current, current->real_parent); |
608 | } | |
609 | ||
610 | write_unlock_irqrestore(&tasklist_lock, flags); | |
f5b40e36 LT |
611 | } |
612 | task_unlock(current); | |
613 | return ret; | |
6b9c7ed8 | 614 | } |
481bed45 | 615 | |
6b9c7ed8 CH |
616 | /** |
617 | * ptrace_get_task_struct -- grab a task struct reference for ptrace | |
618 | * @pid: process id to grab a task_struct reference of | |
619 | * | |
620 | * This function is a helper for ptrace implementations. It checks | |
621 | * permissions and then grabs a task struct for use of the actual | |
622 | * ptrace implementation. | |
623 | * | |
624 | * Returns the task_struct for @pid or an ERR_PTR() on failure. | |
625 | */ | |
626 | struct task_struct *ptrace_get_task_struct(pid_t pid) | |
627 | { | |
628 | struct task_struct *child; | |
481bed45 | 629 | |
481bed45 | 630 | read_lock(&tasklist_lock); |
228ebcbe | 631 | child = find_task_by_vpid(pid); |
481bed45 CH |
632 | if (child) |
633 | get_task_struct(child); | |
f400e198 | 634 | |
481bed45 CH |
635 | read_unlock(&tasklist_lock); |
636 | if (!child) | |
6b9c7ed8 CH |
637 | return ERR_PTR(-ESRCH); |
638 | return child; | |
481bed45 CH |
639 | } |
640 | ||
0ac15559 CH |
641 | #ifndef arch_ptrace_attach |
642 | #define arch_ptrace_attach(child) do { } while (0) | |
643 | #endif | |
644 | ||
1e7bfb21 | 645 | SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data) |
481bed45 CH |
646 | { |
647 | struct task_struct *child; | |
648 | long ret; | |
649 | ||
650 | /* | |
651 | * This lock_kernel fixes a subtle race with suid exec | |
652 | */ | |
653 | lock_kernel(); | |
6b9c7ed8 CH |
654 | if (request == PTRACE_TRACEME) { |
655 | ret = ptrace_traceme(); | |
6ea6dd93 HS |
656 | if (!ret) |
657 | arch_ptrace_attach(current); | |
481bed45 | 658 | goto out; |
6b9c7ed8 CH |
659 | } |
660 | ||
661 | child = ptrace_get_task_struct(pid); | |
662 | if (IS_ERR(child)) { | |
663 | ret = PTR_ERR(child); | |
664 | goto out; | |
665 | } | |
481bed45 CH |
666 | |
667 | if (request == PTRACE_ATTACH) { | |
668 | ret = ptrace_attach(child); | |
0ac15559 CH |
669 | /* |
670 | * Some architectures need to do book-keeping after | |
671 | * a ptrace attach. | |
672 | */ | |
673 | if (!ret) | |
674 | arch_ptrace_attach(child); | |
005f18df | 675 | goto out_put_task_struct; |
481bed45 CH |
676 | } |
677 | ||
678 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
679 | if (ret < 0) | |
680 | goto out_put_task_struct; | |
681 | ||
682 | ret = arch_ptrace(child, request, addr, data); | |
481bed45 CH |
683 | |
684 | out_put_task_struct: | |
685 | put_task_struct(child); | |
686 | out: | |
687 | unlock_kernel(); | |
688 | return ret; | |
689 | } | |
76647323 AD |
690 | |
691 | int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data) | |
692 | { | |
693 | unsigned long tmp; | |
694 | int copied; | |
695 | ||
696 | copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); | |
697 | if (copied != sizeof(tmp)) | |
698 | return -EIO; | |
699 | return put_user(tmp, (unsigned long __user *)data); | |
700 | } | |
f284ce72 AD |
701 | |
702 | int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data) | |
703 | { | |
704 | int copied; | |
705 | ||
706 | copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); | |
707 | return (copied == sizeof(data)) ? 0 : -EIO; | |
708 | } | |
032d82d9 | 709 | |
96b8936a | 710 | #if defined CONFIG_COMPAT |
032d82d9 RM |
711 | #include <linux/compat.h> |
712 | ||
713 | int compat_ptrace_request(struct task_struct *child, compat_long_t request, | |
714 | compat_ulong_t addr, compat_ulong_t data) | |
715 | { | |
716 | compat_ulong_t __user *datap = compat_ptr(data); | |
717 | compat_ulong_t word; | |
e16b2781 | 718 | siginfo_t siginfo; |
032d82d9 RM |
719 | int ret; |
720 | ||
721 | switch (request) { | |
722 | case PTRACE_PEEKTEXT: | |
723 | case PTRACE_PEEKDATA: | |
724 | ret = access_process_vm(child, addr, &word, sizeof(word), 0); | |
725 | if (ret != sizeof(word)) | |
726 | ret = -EIO; | |
727 | else | |
728 | ret = put_user(word, datap); | |
729 | break; | |
730 | ||
731 | case PTRACE_POKETEXT: | |
732 | case PTRACE_POKEDATA: | |
733 | ret = access_process_vm(child, addr, &data, sizeof(data), 1); | |
734 | ret = (ret != sizeof(data) ? -EIO : 0); | |
735 | break; | |
736 | ||
737 | case PTRACE_GETEVENTMSG: | |
738 | ret = put_user((compat_ulong_t) child->ptrace_message, datap); | |
739 | break; | |
740 | ||
e16b2781 RM |
741 | case PTRACE_GETSIGINFO: |
742 | ret = ptrace_getsiginfo(child, &siginfo); | |
743 | if (!ret) | |
744 | ret = copy_siginfo_to_user32( | |
745 | (struct compat_siginfo __user *) datap, | |
746 | &siginfo); | |
747 | break; | |
748 | ||
749 | case PTRACE_SETSIGINFO: | |
750 | memset(&siginfo, 0, sizeof siginfo); | |
751 | if (copy_siginfo_from_user32( | |
752 | &siginfo, (struct compat_siginfo __user *) datap)) | |
753 | ret = -EFAULT; | |
754 | else | |
755 | ret = ptrace_setsiginfo(child, &siginfo); | |
756 | break; | |
757 | ||
032d82d9 RM |
758 | default: |
759 | ret = ptrace_request(child, request, addr, data); | |
760 | } | |
761 | ||
762 | return ret; | |
763 | } | |
c269f196 | 764 | |
c269f196 RM |
765 | asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, |
766 | compat_long_t addr, compat_long_t data) | |
767 | { | |
768 | struct task_struct *child; | |
769 | long ret; | |
770 | ||
771 | /* | |
772 | * This lock_kernel fixes a subtle race with suid exec | |
773 | */ | |
774 | lock_kernel(); | |
775 | if (request == PTRACE_TRACEME) { | |
776 | ret = ptrace_traceme(); | |
777 | goto out; | |
778 | } | |
779 | ||
780 | child = ptrace_get_task_struct(pid); | |
781 | if (IS_ERR(child)) { | |
782 | ret = PTR_ERR(child); | |
783 | goto out; | |
784 | } | |
785 | ||
786 | if (request == PTRACE_ATTACH) { | |
787 | ret = ptrace_attach(child); | |
788 | /* | |
789 | * Some architectures need to do book-keeping after | |
790 | * a ptrace attach. | |
791 | */ | |
792 | if (!ret) | |
793 | arch_ptrace_attach(child); | |
794 | goto out_put_task_struct; | |
795 | } | |
796 | ||
797 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
798 | if (!ret) | |
799 | ret = compat_arch_ptrace(child, request, addr, data); | |
800 | ||
801 | out_put_task_struct: | |
802 | put_task_struct(child); | |
803 | out: | |
804 | unlock_kernel(); | |
805 | return ret; | |
806 | } | |
96b8936a | 807 | #endif /* CONFIG_COMPAT */ |