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Source at commit fbf123cd4cc0c097fe9a99c90109ebb2a5e94a50 created 10 years 3 months ago. By Lars-Peter Clausen, dma: jz4740: Dequeue descriptor from active list before completing it | |
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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 | |
10 | #include <linux/capability.h> |
11 | #include <linux/export.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/ptrace.h> |
18 | #include <linux/security.h> |
19 | #include <linux/signal.h> |
20 | #include <linux/uio.h> |
21 | #include <linux/audit.h> |
22 | #include <linux/pid_namespace.h> |
23 | #include <linux/syscalls.h> |
24 | #include <linux/uaccess.h> |
25 | #include <linux/regset.h> |
26 | #include <linux/hw_breakpoint.h> |
27 | #include <linux/cn_proc.h> |
28 | #include <linux/compat.h> |
29 | |
30 | |
31 | static int ptrace_trapping_sleep_fn(void *flags) |
32 | { |
33 | schedule(); |
34 | return 0; |
35 | } |
36 | |
37 | /* |
38 | * ptrace a task: make the debugger its new parent and |
39 | * move it to the ptrace list. |
40 | * |
41 | * Must be called with the tasklist lock write-held. |
42 | */ |
43 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) |
44 | { |
45 | BUG_ON(!list_empty(&child->ptrace_entry)); |
46 | list_add(&child->ptrace_entry, &new_parent->ptraced); |
47 | child->parent = new_parent; |
48 | } |
49 | |
50 | /** |
51 | * __ptrace_unlink - unlink ptracee and restore its execution state |
52 | * @child: ptracee to be unlinked |
53 | * |
54 | * Remove @child from the ptrace list, move it back to the original parent, |
55 | * and restore the execution state so that it conforms to the group stop |
56 | * state. |
57 | * |
58 | * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer |
59 | * exiting. For PTRACE_DETACH, unless the ptracee has been killed between |
60 | * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. |
61 | * If the ptracer is exiting, the ptracee can be in any state. |
62 | * |
63 | * After detach, the ptracee should be in a state which conforms to the |
64 | * group stop. If the group is stopped or in the process of stopping, the |
65 | * ptracee should be put into TASK_STOPPED; otherwise, it should be woken |
66 | * up from TASK_TRACED. |
67 | * |
68 | * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, |
69 | * it goes through TRACED -> RUNNING -> STOPPED transition which is similar |
70 | * to but in the opposite direction of what happens while attaching to a |
71 | * stopped task. However, in this direction, the intermediate RUNNING |
72 | * state is not hidden even from the current ptracer and if it immediately |
73 | * re-attaches and performs a WNOHANG wait(2), it may fail. |
74 | * |
75 | * CONTEXT: |
76 | * write_lock_irq(tasklist_lock) |
77 | */ |
78 | void __ptrace_unlink(struct task_struct *child) |
79 | { |
80 | BUG_ON(!child->ptrace); |
81 | |
82 | child->ptrace = 0; |
83 | child->parent = child->real_parent; |
84 | list_del_init(&child->ptrace_entry); |
85 | |
86 | spin_lock(&child->sighand->siglock); |
87 | |
88 | /* |
89 | * Clear all pending traps and TRAPPING. TRAPPING should be |
90 | * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. |
91 | */ |
92 | task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); |
93 | task_clear_jobctl_trapping(child); |
94 | |
95 | /* |
96 | * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and |
97 | * @child isn't dead. |
98 | */ |
99 | if (!(child->flags & PF_EXITING) && |
100 | (child->signal->flags & SIGNAL_STOP_STOPPED || |
101 | child->signal->group_stop_count)) { |
102 | child->jobctl |= JOBCTL_STOP_PENDING; |
103 | |
104 | /* |
105 | * This is only possible if this thread was cloned by the |
106 | * traced task running in the stopped group, set the signal |
107 | * for the future reports. |
108 | * FIXME: we should change ptrace_init_task() to handle this |
109 | * case. |
110 | */ |
111 | if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) |
112 | child->jobctl |= SIGSTOP; |
113 | } |
114 | |
115 | /* |
116 | * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick |
117 | * @child in the butt. Note that @resume should be used iff @child |
118 | * is in TASK_TRACED; otherwise, we might unduly disrupt |
119 | * TASK_KILLABLE sleeps. |
120 | */ |
121 | if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) |
122 | ptrace_signal_wake_up(child, true); |
123 | |
124 | spin_unlock(&child->sighand->siglock); |
125 | } |
126 | |
127 | /* Ensure that nothing can wake it up, even SIGKILL */ |
128 | static bool ptrace_freeze_traced(struct task_struct *task) |
129 | { |
130 | bool ret = false; |
131 | |
132 | /* Lockless, nobody but us can set this flag */ |
133 | if (task->jobctl & JOBCTL_LISTENING) |
134 | return ret; |
135 | |
136 | spin_lock_irq(&task->sighand->siglock); |
137 | if (task_is_traced(task) && !__fatal_signal_pending(task)) { |
138 | task->state = __TASK_TRACED; |
139 | ret = true; |
140 | } |
141 | spin_unlock_irq(&task->sighand->siglock); |
142 | |
143 | return ret; |
144 | } |
145 | |
146 | static void ptrace_unfreeze_traced(struct task_struct *task) |
147 | { |
148 | if (task->state != __TASK_TRACED) |
149 | return; |
150 | |
151 | WARN_ON(!task->ptrace || task->parent != current); |
152 | |
153 | spin_lock_irq(&task->sighand->siglock); |
154 | if (__fatal_signal_pending(task)) |
155 | wake_up_state(task, __TASK_TRACED); |
156 | else |
157 | task->state = TASK_TRACED; |
158 | spin_unlock_irq(&task->sighand->siglock); |
159 | } |
160 | |
161 | /** |
162 | * ptrace_check_attach - check whether ptracee is ready for ptrace operation |
163 | * @child: ptracee to check for |
164 | * @ignore_state: don't check whether @child is currently %TASK_TRACED |
165 | * |
166 | * Check whether @child is being ptraced by %current and ready for further |
167 | * ptrace operations. If @ignore_state is %false, @child also should be in |
168 | * %TASK_TRACED state and on return the child is guaranteed to be traced |
169 | * and not executing. If @ignore_state is %true, @child can be in any |
170 | * state. |
171 | * |
172 | * CONTEXT: |
173 | * Grabs and releases tasklist_lock and @child->sighand->siglock. |
174 | * |
175 | * RETURNS: |
176 | * 0 on success, -ESRCH if %child is not ready. |
177 | */ |
178 | static int ptrace_check_attach(struct task_struct *child, bool ignore_state) |
179 | { |
180 | int ret = -ESRCH; |
181 | |
182 | /* |
183 | * We take the read lock around doing both checks to close a |
184 | * possible race where someone else was tracing our child and |
185 | * detached between these two checks. After this locked check, |
186 | * we are sure that this is our traced child and that can only |
187 | * be changed by us so it's not changing right after this. |
188 | */ |
189 | read_lock(&tasklist_lock); |
190 | if (child->ptrace && child->parent == current) { |
191 | WARN_ON(child->state == __TASK_TRACED); |
192 | /* |
193 | * child->sighand can't be NULL, release_task() |
194 | * does ptrace_unlink() before __exit_signal(). |
195 | */ |
196 | if (ignore_state || ptrace_freeze_traced(child)) |
197 | ret = 0; |
198 | } |
199 | read_unlock(&tasklist_lock); |
200 | |
201 | if (!ret && !ignore_state) { |
202 | if (!wait_task_inactive(child, __TASK_TRACED)) { |
203 | /* |
204 | * This can only happen if may_ptrace_stop() fails and |
205 | * ptrace_stop() changes ->state back to TASK_RUNNING, |
206 | * so we should not worry about leaking __TASK_TRACED. |
207 | */ |
208 | WARN_ON(child->state == __TASK_TRACED); |
209 | ret = -ESRCH; |
210 | } |
211 | } |
212 | |
213 | return ret; |
214 | } |
215 | |
216 | static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) |
217 | { |
218 | if (mode & PTRACE_MODE_NOAUDIT) |
219 | return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); |
220 | else |
221 | return has_ns_capability(current, ns, CAP_SYS_PTRACE); |
222 | } |
223 | |
224 | /* Returns 0 on success, -errno on denial. */ |
225 | static int __ptrace_may_access(struct task_struct *task, unsigned int mode) |
226 | { |
227 | const struct cred *cred = current_cred(), *tcred; |
228 | |
229 | /* May we inspect the given task? |
230 | * This check is used both for attaching with ptrace |
231 | * and for allowing access to sensitive information in /proc. |
232 | * |
233 | * ptrace_attach denies several cases that /proc allows |
234 | * because setting up the necessary parent/child relationship |
235 | * or halting the specified task is impossible. |
236 | */ |
237 | int dumpable = 0; |
238 | /* Don't let security modules deny introspection */ |
239 | if (same_thread_group(task, current)) |
240 | return 0; |
241 | rcu_read_lock(); |
242 | tcred = __task_cred(task); |
243 | if (uid_eq(cred->uid, tcred->euid) && |
244 | uid_eq(cred->uid, tcred->suid) && |
245 | uid_eq(cred->uid, tcred->uid) && |
246 | gid_eq(cred->gid, tcred->egid) && |
247 | gid_eq(cred->gid, tcred->sgid) && |
248 | gid_eq(cred->gid, tcred->gid)) |
249 | goto ok; |
250 | if (ptrace_has_cap(tcred->user_ns, mode)) |
251 | goto ok; |
252 | rcu_read_unlock(); |
253 | return -EPERM; |
254 | ok: |
255 | rcu_read_unlock(); |
256 | smp_rmb(); |
257 | if (task->mm) |
258 | dumpable = get_dumpable(task->mm); |
259 | rcu_read_lock(); |
260 | if (dumpable != SUID_DUMP_USER && |
261 | !ptrace_has_cap(__task_cred(task)->user_ns, mode)) { |
262 | rcu_read_unlock(); |
263 | return -EPERM; |
264 | } |
265 | rcu_read_unlock(); |
266 | |
267 | return security_ptrace_access_check(task, mode); |
268 | } |
269 | |
270 | bool ptrace_may_access(struct task_struct *task, unsigned int mode) |
271 | { |
272 | int err; |
273 | task_lock(task); |
274 | err = __ptrace_may_access(task, mode); |
275 | task_unlock(task); |
276 | return !err; |
277 | } |
278 | |
279 | static int ptrace_attach(struct task_struct *task, long request, |
280 | unsigned long addr, |
281 | unsigned long flags) |
282 | { |
283 | bool seize = (request == PTRACE_SEIZE); |
284 | int retval; |
285 | |
286 | retval = -EIO; |
287 | if (seize) { |
288 | if (addr != 0) |
289 | goto out; |
290 | if (flags & ~(unsigned long)PTRACE_O_MASK) |
291 | goto out; |
292 | flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); |
293 | } else { |
294 | flags = PT_PTRACED; |
295 | } |
296 | |
297 | audit_ptrace(task); |
298 | |
299 | retval = -EPERM; |
300 | if (unlikely(task->flags & PF_KTHREAD)) |
301 | goto out; |
302 | if (same_thread_group(task, current)) |
303 | goto out; |
304 | |
305 | /* |
306 | * Protect exec's credential calculations against our interference; |
307 | * SUID, SGID and LSM creds get determined differently |
308 | * under ptrace. |
309 | */ |
310 | retval = -ERESTARTNOINTR; |
311 | if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) |
312 | goto out; |
313 | |
314 | task_lock(task); |
315 | retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); |
316 | task_unlock(task); |
317 | if (retval) |
318 | goto unlock_creds; |
319 | |
320 | write_lock_irq(&tasklist_lock); |
321 | retval = -EPERM; |
322 | if (unlikely(task->exit_state)) |
323 | goto unlock_tasklist; |
324 | if (task->ptrace) |
325 | goto unlock_tasklist; |
326 | |
327 | if (seize) |
328 | flags |= PT_SEIZED; |
329 | rcu_read_lock(); |
330 | if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE)) |
331 | flags |= PT_PTRACE_CAP; |
332 | rcu_read_unlock(); |
333 | task->ptrace = flags; |
334 | |
335 | __ptrace_link(task, current); |
336 | |
337 | /* SEIZE doesn't trap tracee on attach */ |
338 | if (!seize) |
339 | send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); |
340 | |
341 | spin_lock(&task->sighand->siglock); |
342 | |
343 | /* |
344 | * If the task is already STOPPED, set JOBCTL_TRAP_STOP and |
345 | * TRAPPING, and kick it so that it transits to TRACED. TRAPPING |
346 | * will be cleared if the child completes the transition or any |
347 | * event which clears the group stop states happens. We'll wait |
348 | * for the transition to complete before returning from this |
349 | * function. |
350 | * |
351 | * This hides STOPPED -> RUNNING -> TRACED transition from the |
352 | * attaching thread but a different thread in the same group can |
353 | * still observe the transient RUNNING state. IOW, if another |
354 | * thread's WNOHANG wait(2) on the stopped tracee races against |
355 | * ATTACH, the wait(2) may fail due to the transient RUNNING. |
356 | * |
357 | * The following task_is_stopped() test is safe as both transitions |
358 | * in and out of STOPPED are protected by siglock. |
359 | */ |
360 | if (task_is_stopped(task) && |
361 | task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) |
362 | signal_wake_up_state(task, __TASK_STOPPED); |
363 | |
364 | spin_unlock(&task->sighand->siglock); |
365 | |
366 | retval = 0; |
367 | unlock_tasklist: |
368 | write_unlock_irq(&tasklist_lock); |
369 | unlock_creds: |
370 | mutex_unlock(&task->signal->cred_guard_mutex); |
371 | out: |
372 | if (!retval) { |
373 | wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, |
374 | ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); |
375 | proc_ptrace_connector(task, PTRACE_ATTACH); |
376 | } |
377 | |
378 | return retval; |
379 | } |
380 | |
381 | /** |
382 | * ptrace_traceme -- helper for PTRACE_TRACEME |
383 | * |
384 | * Performs checks and sets PT_PTRACED. |
385 | * Should be used by all ptrace implementations for PTRACE_TRACEME. |
386 | */ |
387 | static int ptrace_traceme(void) |
388 | { |
389 | int ret = -EPERM; |
390 | |
391 | write_lock_irq(&tasklist_lock); |
392 | /* Are we already being traced? */ |
393 | if (!current->ptrace) { |
394 | ret = security_ptrace_traceme(current->parent); |
395 | /* |
396 | * Check PF_EXITING to ensure ->real_parent has not passed |
397 | * exit_ptrace(). Otherwise we don't report the error but |
398 | * pretend ->real_parent untraces us right after return. |
399 | */ |
400 | if (!ret && !(current->real_parent->flags & PF_EXITING)) { |
401 | current->ptrace = PT_PTRACED; |
402 | __ptrace_link(current, current->real_parent); |
403 | } |
404 | } |
405 | write_unlock_irq(&tasklist_lock); |
406 | |
407 | return ret; |
408 | } |
409 | |
410 | /* |
411 | * Called with irqs disabled, returns true if childs should reap themselves. |
412 | */ |
413 | static int ignoring_children(struct sighand_struct *sigh) |
414 | { |
415 | int ret; |
416 | spin_lock(&sigh->siglock); |
417 | ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || |
418 | (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); |
419 | spin_unlock(&sigh->siglock); |
420 | return ret; |
421 | } |
422 | |
423 | /* |
424 | * Called with tasklist_lock held for writing. |
425 | * Unlink a traced task, and clean it up if it was a traced zombie. |
426 | * Return true if it needs to be reaped with release_task(). |
427 | * (We can't call release_task() here because we already hold tasklist_lock.) |
428 | * |
429 | * If it's a zombie, our attachedness prevented normal parent notification |
430 | * or self-reaping. Do notification now if it would have happened earlier. |
431 | * If it should reap itself, return true. |
432 | * |
433 | * If it's our own child, there is no notification to do. But if our normal |
434 | * children self-reap, then this child was prevented by ptrace and we must |
435 | * reap it now, in that case we must also wake up sub-threads sleeping in |
436 | * do_wait(). |
437 | */ |
438 | static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) |
439 | { |
440 | bool dead; |
441 | |
442 | __ptrace_unlink(p); |
443 | |
444 | if (p->exit_state != EXIT_ZOMBIE) |
445 | return false; |
446 | |
447 | dead = !thread_group_leader(p); |
448 | |
449 | if (!dead && thread_group_empty(p)) { |
450 | if (!same_thread_group(p->real_parent, tracer)) |
451 | dead = do_notify_parent(p, p->exit_signal); |
452 | else if (ignoring_children(tracer->sighand)) { |
453 | __wake_up_parent(p, tracer); |
454 | dead = true; |
455 | } |
456 | } |
457 | /* Mark it as in the process of being reaped. */ |
458 | if (dead) |
459 | p->exit_state = EXIT_DEAD; |
460 | return dead; |
461 | } |
462 | |
463 | static int ptrace_detach(struct task_struct *child, unsigned int data) |
464 | { |
465 | bool dead = false; |
466 | |
467 | if (!valid_signal(data)) |
468 | return -EIO; |
469 | |
470 | /* Architecture-specific hardware disable .. */ |
471 | ptrace_disable(child); |
472 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
473 | |
474 | write_lock_irq(&tasklist_lock); |
475 | /* |
476 | * This child can be already killed. Make sure de_thread() or |
477 | * our sub-thread doing do_wait() didn't do release_task() yet. |
478 | */ |
479 | if (child->ptrace) { |
480 | child->exit_code = data; |
481 | dead = __ptrace_detach(current, child); |
482 | } |
483 | write_unlock_irq(&tasklist_lock); |
484 | |
485 | proc_ptrace_connector(child, PTRACE_DETACH); |
486 | if (unlikely(dead)) |
487 | release_task(child); |
488 | |
489 | return 0; |
490 | } |
491 | |
492 | /* |
493 | * Detach all tasks we were using ptrace on. Called with tasklist held |
494 | * for writing, and returns with it held too. But note it can release |
495 | * and reacquire the lock. |
496 | */ |
497 | void exit_ptrace(struct task_struct *tracer) |
498 | __releases(&tasklist_lock) |
499 | __acquires(&tasklist_lock) |
500 | { |
501 | struct task_struct *p, *n; |
502 | LIST_HEAD(ptrace_dead); |
503 | |
504 | if (likely(list_empty(&tracer->ptraced))) |
505 | return; |
506 | |
507 | list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { |
508 | if (unlikely(p->ptrace & PT_EXITKILL)) |
509 | send_sig_info(SIGKILL, SEND_SIG_FORCED, p); |
510 | |
511 | if (__ptrace_detach(tracer, p)) |
512 | list_add(&p->ptrace_entry, &ptrace_dead); |
513 | } |
514 | |
515 | write_unlock_irq(&tasklist_lock); |
516 | BUG_ON(!list_empty(&tracer->ptraced)); |
517 | |
518 | list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { |
519 | list_del_init(&p->ptrace_entry); |
520 | release_task(p); |
521 | } |
522 | |
523 | write_lock_irq(&tasklist_lock); |
524 | } |
525 | |
526 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) |
527 | { |
528 | int copied = 0; |
529 | |
530 | while (len > 0) { |
531 | char buf[128]; |
532 | int this_len, retval; |
533 | |
534 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; |
535 | retval = access_process_vm(tsk, src, buf, this_len, 0); |
536 | if (!retval) { |
537 | if (copied) |
538 | break; |
539 | return -EIO; |
540 | } |
541 | if (copy_to_user(dst, buf, retval)) |
542 | return -EFAULT; |
543 | copied += retval; |
544 | src += retval; |
545 | dst += retval; |
546 | len -= retval; |
547 | } |
548 | return copied; |
549 | } |
550 | |
551 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) |
552 | { |
553 | int copied = 0; |
554 | |
555 | while (len > 0) { |
556 | char buf[128]; |
557 | int this_len, retval; |
558 | |
559 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; |
560 | if (copy_from_user(buf, src, this_len)) |
561 | return -EFAULT; |
562 | retval = access_process_vm(tsk, dst, buf, this_len, 1); |
563 | if (!retval) { |
564 | if (copied) |
565 | break; |
566 | return -EIO; |
567 | } |
568 | copied += retval; |
569 | src += retval; |
570 | dst += retval; |
571 | len -= retval; |
572 | } |
573 | return copied; |
574 | } |
575 | |
576 | static int ptrace_setoptions(struct task_struct *child, unsigned long data) |
577 | { |
578 | unsigned flags; |
579 | |
580 | if (data & ~(unsigned long)PTRACE_O_MASK) |
581 | return -EINVAL; |
582 | |
583 | /* Avoid intermediate state when all opts are cleared */ |
584 | flags = child->ptrace; |
585 | flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); |
586 | flags |= (data << PT_OPT_FLAG_SHIFT); |
587 | child->ptrace = flags; |
588 | |
589 | return 0; |
590 | } |
591 | |
592 | static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) |
593 | { |
594 | unsigned long flags; |
595 | int error = -ESRCH; |
596 | |
597 | if (lock_task_sighand(child, &flags)) { |
598 | error = -EINVAL; |
599 | if (likely(child->last_siginfo != NULL)) { |
600 | *info = *child->last_siginfo; |
601 | error = 0; |
602 | } |
603 | unlock_task_sighand(child, &flags); |
604 | } |
605 | return error; |
606 | } |
607 | |
608 | static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) |
609 | { |
610 | unsigned long flags; |
611 | int error = -ESRCH; |
612 | |
613 | if (lock_task_sighand(child, &flags)) { |
614 | error = -EINVAL; |
615 | if (likely(child->last_siginfo != NULL)) { |
616 | *child->last_siginfo = *info; |
617 | error = 0; |
618 | } |
619 | unlock_task_sighand(child, &flags); |
620 | } |
621 | return error; |
622 | } |
623 | |
624 | static int ptrace_peek_siginfo(struct task_struct *child, |
625 | unsigned long addr, |
626 | unsigned long data) |
627 | { |
628 | struct ptrace_peeksiginfo_args arg; |
629 | struct sigpending *pending; |
630 | struct sigqueue *q; |
631 | int ret, i; |
632 | |
633 | ret = copy_from_user(&arg, (void __user *) addr, |
634 | sizeof(struct ptrace_peeksiginfo_args)); |
635 | if (ret) |
636 | return -EFAULT; |
637 | |
638 | if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) |
639 | return -EINVAL; /* unknown flags */ |
640 | |
641 | if (arg.nr < 0) |
642 | return -EINVAL; |
643 | |
644 | if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) |
645 | pending = &child->signal->shared_pending; |
646 | else |
647 | pending = &child->pending; |
648 | |
649 | for (i = 0; i < arg.nr; ) { |
650 | siginfo_t info; |
651 | s32 off = arg.off + i; |
652 | |
653 | spin_lock_irq(&child->sighand->siglock); |
654 | list_for_each_entry(q, &pending->list, list) { |
655 | if (!off--) { |
656 | copy_siginfo(&info, &q->info); |
657 | break; |
658 | } |
659 | } |
660 | spin_unlock_irq(&child->sighand->siglock); |
661 | |
662 | if (off >= 0) /* beyond the end of the list */ |
663 | break; |
664 | |
665 | #ifdef CONFIG_COMPAT |
666 | if (unlikely(is_compat_task())) { |
667 | compat_siginfo_t __user *uinfo = compat_ptr(data); |
668 | |
669 | if (copy_siginfo_to_user32(uinfo, &info) || |
670 | __put_user(info.si_code, &uinfo->si_code)) { |
671 | ret = -EFAULT; |
672 | break; |
673 | } |
674 | |
675 | } else |
676 | #endif |
677 | { |
678 | siginfo_t __user *uinfo = (siginfo_t __user *) data; |
679 | |
680 | if (copy_siginfo_to_user(uinfo, &info) || |
681 | __put_user(info.si_code, &uinfo->si_code)) { |
682 | ret = -EFAULT; |
683 | break; |
684 | } |
685 | } |
686 | |
687 | data += sizeof(siginfo_t); |
688 | i++; |
689 | |
690 | if (signal_pending(current)) |
691 | break; |
692 | |
693 | cond_resched(); |
694 | } |
695 | |
696 | if (i > 0) |
697 | return i; |
698 | |
699 | return ret; |
700 | } |
701 | |
702 | #ifdef PTRACE_SINGLESTEP |
703 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) |
704 | #else |
705 | #define is_singlestep(request) 0 |
706 | #endif |
707 | |
708 | #ifdef PTRACE_SINGLEBLOCK |
709 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) |
710 | #else |
711 | #define is_singleblock(request) 0 |
712 | #endif |
713 | |
714 | #ifdef PTRACE_SYSEMU |
715 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) |
716 | #else |
717 | #define is_sysemu_singlestep(request) 0 |
718 | #endif |
719 | |
720 | static int ptrace_resume(struct task_struct *child, long request, |
721 | unsigned long data) |
722 | { |
723 | if (!valid_signal(data)) |
724 | return -EIO; |
725 | |
726 | if (request == PTRACE_SYSCALL) |
727 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
728 | else |
729 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
730 | |
731 | #ifdef TIF_SYSCALL_EMU |
732 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) |
733 | set_tsk_thread_flag(child, TIF_SYSCALL_EMU); |
734 | else |
735 | clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); |
736 | #endif |
737 | |
738 | if (is_singleblock(request)) { |
739 | if (unlikely(!arch_has_block_step())) |
740 | return -EIO; |
741 | user_enable_block_step(child); |
742 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { |
743 | if (unlikely(!arch_has_single_step())) |
744 | return -EIO; |
745 | user_enable_single_step(child); |
746 | } else { |
747 | user_disable_single_step(child); |
748 | } |
749 | |
750 | child->exit_code = data; |
751 | wake_up_state(child, __TASK_TRACED); |
752 | |
753 | return 0; |
754 | } |
755 | |
756 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK |
757 | |
758 | static const struct user_regset * |
759 | find_regset(const struct user_regset_view *view, unsigned int type) |
760 | { |
761 | const struct user_regset *regset; |
762 | int n; |
763 | |
764 | for (n = 0; n < view->n; ++n) { |
765 | regset = view->regsets + n; |
766 | if (regset->core_note_type == type) |
767 | return regset; |
768 | } |
769 | |
770 | return NULL; |
771 | } |
772 | |
773 | static int ptrace_regset(struct task_struct *task, int req, unsigned int type, |
774 | struct iovec *kiov) |
775 | { |
776 | const struct user_regset_view *view = task_user_regset_view(task); |
777 | const struct user_regset *regset = find_regset(view, type); |
778 | int regset_no; |
779 | |
780 | if (!regset || (kiov->iov_len % regset->size) != 0) |
781 | return -EINVAL; |
782 | |
783 | regset_no = regset - view->regsets; |
784 | kiov->iov_len = min(kiov->iov_len, |
785 | (__kernel_size_t) (regset->n * regset->size)); |
786 | |
787 | if (req == PTRACE_GETREGSET) |
788 | return copy_regset_to_user(task, view, regset_no, 0, |
789 | kiov->iov_len, kiov->iov_base); |
790 | else |
791 | return copy_regset_from_user(task, view, regset_no, 0, |
792 | kiov->iov_len, kiov->iov_base); |
793 | } |
794 | |
795 | /* |
796 | * This is declared in linux/regset.h and defined in machine-dependent |
797 | * code. We put the export here, near the primary machine-neutral use, |
798 | * to ensure no machine forgets it. |
799 | */ |
800 | EXPORT_SYMBOL_GPL(task_user_regset_view); |
801 | #endif |
802 | |
803 | int ptrace_request(struct task_struct *child, long request, |
804 | unsigned long addr, unsigned long data) |
805 | { |
806 | bool seized = child->ptrace & PT_SEIZED; |
807 | int ret = -EIO; |
808 | siginfo_t siginfo, *si; |
809 | void __user *datavp = (void __user *) data; |
810 | unsigned long __user *datalp = datavp; |
811 | unsigned long flags; |
812 | |
813 | switch (request) { |
814 | case PTRACE_PEEKTEXT: |
815 | case PTRACE_PEEKDATA: |
816 | return generic_ptrace_peekdata(child, addr, data); |
817 | case PTRACE_POKETEXT: |
818 | case PTRACE_POKEDATA: |
819 | return generic_ptrace_pokedata(child, addr, data); |
820 | |
821 | #ifdef PTRACE_OLDSETOPTIONS |
822 | case PTRACE_OLDSETOPTIONS: |
823 | #endif |
824 | case PTRACE_SETOPTIONS: |
825 | ret = ptrace_setoptions(child, data); |
826 | break; |
827 | case PTRACE_GETEVENTMSG: |
828 | ret = put_user(child->ptrace_message, datalp); |
829 | break; |
830 | |
831 | case PTRACE_PEEKSIGINFO: |
832 | ret = ptrace_peek_siginfo(child, addr, data); |
833 | break; |
834 | |
835 | case PTRACE_GETSIGINFO: |
836 | ret = ptrace_getsiginfo(child, &siginfo); |
837 | if (!ret) |
838 | ret = copy_siginfo_to_user(datavp, &siginfo); |
839 | break; |
840 | |
841 | case PTRACE_SETSIGINFO: |
842 | if (copy_from_user(&siginfo, datavp, sizeof siginfo)) |
843 | ret = -EFAULT; |
844 | else |
845 | ret = ptrace_setsiginfo(child, &siginfo); |
846 | break; |
847 | |
848 | case PTRACE_GETSIGMASK: |
849 | if (addr != sizeof(sigset_t)) { |
850 | ret = -EINVAL; |
851 | break; |
852 | } |
853 | |
854 | if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) |
855 | ret = -EFAULT; |
856 | else |
857 | ret = 0; |
858 | |
859 | break; |
860 | |
861 | case PTRACE_SETSIGMASK: { |
862 | sigset_t new_set; |
863 | |
864 | if (addr != sizeof(sigset_t)) { |
865 | ret = -EINVAL; |
866 | break; |
867 | } |
868 | |
869 | if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { |
870 | ret = -EFAULT; |
871 | break; |
872 | } |
873 | |
874 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); |
875 | |
876 | /* |
877 | * Every thread does recalc_sigpending() after resume, so |
878 | * retarget_shared_pending() and recalc_sigpending() are not |
879 | * called here. |
880 | */ |
881 | spin_lock_irq(&child->sighand->siglock); |
882 | child->blocked = new_set; |
883 | spin_unlock_irq(&child->sighand->siglock); |
884 | |
885 | ret = 0; |
886 | break; |
887 | } |
888 | |
889 | case PTRACE_INTERRUPT: |
890 | /* |
891 | * Stop tracee without any side-effect on signal or job |
892 | * control. At least one trap is guaranteed to happen |
893 | * after this request. If @child is already trapped, the |
894 | * current trap is not disturbed and another trap will |
895 | * happen after the current trap is ended with PTRACE_CONT. |
896 | * |
897 | * The actual trap might not be PTRACE_EVENT_STOP trap but |
898 | * the pending condition is cleared regardless. |
899 | */ |
900 | if (unlikely(!seized || !lock_task_sighand(child, &flags))) |
901 | break; |
902 | |
903 | /* |
904 | * INTERRUPT doesn't disturb existing trap sans one |
905 | * exception. If ptracer issued LISTEN for the current |
906 | * STOP, this INTERRUPT should clear LISTEN and re-trap |
907 | * tracee into STOP. |
908 | */ |
909 | if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) |
910 | ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); |
911 | |
912 | unlock_task_sighand(child, &flags); |
913 | ret = 0; |
914 | break; |
915 | |
916 | case PTRACE_LISTEN: |
917 | /* |
918 | * Listen for events. Tracee must be in STOP. It's not |
919 | * resumed per-se but is not considered to be in TRACED by |
920 | * wait(2) or ptrace(2). If an async event (e.g. group |
921 | * stop state change) happens, tracee will enter STOP trap |
922 | * again. Alternatively, ptracer can issue INTERRUPT to |
923 | * finish listening and re-trap tracee into STOP. |
924 | */ |
925 | if (unlikely(!seized || !lock_task_sighand(child, &flags))) |
926 | break; |
927 | |
928 | si = child->last_siginfo; |
929 | if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { |
930 | child->jobctl |= JOBCTL_LISTENING; |
931 | /* |
932 | * If NOTIFY is set, it means event happened between |
933 | * start of this trap and now. Trigger re-trap. |
934 | */ |
935 | if (child->jobctl & JOBCTL_TRAP_NOTIFY) |
936 | ptrace_signal_wake_up(child, true); |
937 | ret = 0; |
938 | } |
939 | unlock_task_sighand(child, &flags); |
940 | break; |
941 | |
942 | case PTRACE_DETACH: /* detach a process that was attached. */ |
943 | ret = ptrace_detach(child, data); |
944 | break; |
945 | |
946 | #ifdef CONFIG_BINFMT_ELF_FDPIC |
947 | case PTRACE_GETFDPIC: { |
948 | struct mm_struct *mm = get_task_mm(child); |
949 | unsigned long tmp = 0; |
950 | |
951 | ret = -ESRCH; |
952 | if (!mm) |
953 | break; |
954 | |
955 | switch (addr) { |
956 | case PTRACE_GETFDPIC_EXEC: |
957 | tmp = mm->context.exec_fdpic_loadmap; |
958 | break; |
959 | case PTRACE_GETFDPIC_INTERP: |
960 | tmp = mm->context.interp_fdpic_loadmap; |
961 | break; |
962 | default: |
963 | break; |
964 | } |
965 | mmput(mm); |
966 | |
967 | ret = put_user(tmp, datalp); |
968 | break; |
969 | } |
970 | #endif |
971 | |
972 | #ifdef PTRACE_SINGLESTEP |
973 | case PTRACE_SINGLESTEP: |
974 | #endif |
975 | #ifdef PTRACE_SINGLEBLOCK |
976 | case PTRACE_SINGLEBLOCK: |
977 | #endif |
978 | #ifdef PTRACE_SYSEMU |
979 | case PTRACE_SYSEMU: |
980 | case PTRACE_SYSEMU_SINGLESTEP: |
981 | #endif |
982 | case PTRACE_SYSCALL: |
983 | case PTRACE_CONT: |
984 | return ptrace_resume(child, request, data); |
985 | |
986 | case PTRACE_KILL: |
987 | if (child->exit_state) /* already dead */ |
988 | return 0; |
989 | return ptrace_resume(child, request, SIGKILL); |
990 | |
991 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK |
992 | case PTRACE_GETREGSET: |
993 | case PTRACE_SETREGSET: { |
994 | struct iovec kiov; |
995 | struct iovec __user *uiov = datavp; |
996 | |
997 | if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) |
998 | return -EFAULT; |
999 | |
1000 | if (__get_user(kiov.iov_base, &uiov->iov_base) || |
1001 | __get_user(kiov.iov_len, &uiov->iov_len)) |
1002 | return -EFAULT; |
1003 | |
1004 | ret = ptrace_regset(child, request, addr, &kiov); |
1005 | if (!ret) |
1006 | ret = __put_user(kiov.iov_len, &uiov->iov_len); |
1007 | break; |
1008 | } |
1009 | #endif |
1010 | default: |
1011 | break; |
1012 | } |
1013 | |
1014 | return ret; |
1015 | } |
1016 | |
1017 | static struct task_struct *ptrace_get_task_struct(pid_t pid) |
1018 | { |
1019 | struct task_struct *child; |
1020 | |
1021 | rcu_read_lock(); |
1022 | child = find_task_by_vpid(pid); |
1023 | if (child) |
1024 | get_task_struct(child); |
1025 | rcu_read_unlock(); |
1026 | |
1027 | if (!child) |
1028 | return ERR_PTR(-ESRCH); |
1029 | return child; |
1030 | } |
1031 | |
1032 | #ifndef arch_ptrace_attach |
1033 | #define arch_ptrace_attach(child) do { } while (0) |
1034 | #endif |
1035 | |
1036 | SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, |
1037 | unsigned long, data) |
1038 | { |
1039 | struct task_struct *child; |
1040 | long ret; |
1041 | |
1042 | if (request == PTRACE_TRACEME) { |
1043 | ret = ptrace_traceme(); |
1044 | if (!ret) |
1045 | arch_ptrace_attach(current); |
1046 | goto out; |
1047 | } |
1048 | |
1049 | child = ptrace_get_task_struct(pid); |
1050 | if (IS_ERR(child)) { |
1051 | ret = PTR_ERR(child); |
1052 | goto out; |
1053 | } |
1054 | |
1055 | if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { |
1056 | ret = ptrace_attach(child, request, addr, data); |
1057 | /* |
1058 | * Some architectures need to do book-keeping after |
1059 | * a ptrace attach. |
1060 | */ |
1061 | if (!ret) |
1062 | arch_ptrace_attach(child); |
1063 | goto out_put_task_struct; |
1064 | } |
1065 | |
1066 | ret = ptrace_check_attach(child, request == PTRACE_KILL || |
1067 | request == PTRACE_INTERRUPT); |
1068 | if (ret < 0) |
1069 | goto out_put_task_struct; |
1070 | |
1071 | ret = arch_ptrace(child, request, addr, data); |
1072 | if (ret || request != PTRACE_DETACH) |
1073 | ptrace_unfreeze_traced(child); |
1074 | |
1075 | out_put_task_struct: |
1076 | put_task_struct(child); |
1077 | out: |
1078 | return ret; |
1079 | } |
1080 | |
1081 | int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, |
1082 | unsigned long data) |
1083 | { |
1084 | unsigned long tmp; |
1085 | int copied; |
1086 | |
1087 | copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); |
1088 | if (copied != sizeof(tmp)) |
1089 | return -EIO; |
1090 | return put_user(tmp, (unsigned long __user *)data); |
1091 | } |
1092 | |
1093 | int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, |
1094 | unsigned long data) |
1095 | { |
1096 | int copied; |
1097 | |
1098 | copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); |
1099 | return (copied == sizeof(data)) ? 0 : -EIO; |
1100 | } |
1101 | |
1102 | #if defined CONFIG_COMPAT |
1103 | #include <linux/compat.h> |
1104 | |
1105 | int compat_ptrace_request(struct task_struct *child, compat_long_t request, |
1106 | compat_ulong_t addr, compat_ulong_t data) |
1107 | { |
1108 | compat_ulong_t __user *datap = compat_ptr(data); |
1109 | compat_ulong_t word; |
1110 | siginfo_t siginfo; |
1111 | int ret; |
1112 | |
1113 | switch (request) { |
1114 | case PTRACE_PEEKTEXT: |
1115 | case PTRACE_PEEKDATA: |
1116 | ret = access_process_vm(child, addr, &word, sizeof(word), 0); |
1117 | if (ret != sizeof(word)) |
1118 | ret = -EIO; |
1119 | else |
1120 | ret = put_user(word, datap); |
1121 | break; |
1122 | |
1123 | case PTRACE_POKETEXT: |
1124 | case PTRACE_POKEDATA: |
1125 | ret = access_process_vm(child, addr, &data, sizeof(data), 1); |
1126 | ret = (ret != sizeof(data) ? -EIO : 0); |
1127 | break; |
1128 | |
1129 | case PTRACE_GETEVENTMSG: |
1130 | ret = put_user((compat_ulong_t) child->ptrace_message, datap); |
1131 | break; |
1132 | |
1133 | case PTRACE_GETSIGINFO: |
1134 | ret = ptrace_getsiginfo(child, &siginfo); |
1135 | if (!ret) |
1136 | ret = copy_siginfo_to_user32( |
1137 | (struct compat_siginfo __user *) datap, |
1138 | &siginfo); |
1139 | break; |
1140 | |
1141 | case PTRACE_SETSIGINFO: |
1142 | memset(&siginfo, 0, sizeof siginfo); |
1143 | if (copy_siginfo_from_user32( |
1144 | &siginfo, (struct compat_siginfo __user *) datap)) |
1145 | ret = -EFAULT; |
1146 | else |
1147 | ret = ptrace_setsiginfo(child, &siginfo); |
1148 | break; |
1149 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK |
1150 | case PTRACE_GETREGSET: |
1151 | case PTRACE_SETREGSET: |
1152 | { |
1153 | struct iovec kiov; |
1154 | struct compat_iovec __user *uiov = |
1155 | (struct compat_iovec __user *) datap; |
1156 | compat_uptr_t ptr; |
1157 | compat_size_t len; |
1158 | |
1159 | if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) |
1160 | return -EFAULT; |
1161 | |
1162 | if (__get_user(ptr, &uiov->iov_base) || |
1163 | __get_user(len, &uiov->iov_len)) |
1164 | return -EFAULT; |
1165 | |
1166 | kiov.iov_base = compat_ptr(ptr); |
1167 | kiov.iov_len = len; |
1168 | |
1169 | ret = ptrace_regset(child, request, addr, &kiov); |
1170 | if (!ret) |
1171 | ret = __put_user(kiov.iov_len, &uiov->iov_len); |
1172 | break; |
1173 | } |
1174 | #endif |
1175 | |
1176 | default: |
1177 | ret = ptrace_request(child, request, addr, data); |
1178 | } |
1179 | |
1180 | return ret; |
1181 | } |
1182 | |
1183 | COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, |
1184 | compat_long_t, addr, compat_long_t, data) |
1185 | { |
1186 | struct task_struct *child; |
1187 | long ret; |
1188 | |
1189 | if (request == PTRACE_TRACEME) { |
1190 | ret = ptrace_traceme(); |
1191 | goto out; |
1192 | } |
1193 | |
1194 | child = ptrace_get_task_struct(pid); |
1195 | if (IS_ERR(child)) { |
1196 | ret = PTR_ERR(child); |
1197 | goto out; |
1198 | } |
1199 | |
1200 | if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { |
1201 | ret = ptrace_attach(child, request, addr, data); |
1202 | /* |
1203 | * Some architectures need to do book-keeping after |
1204 | * a ptrace attach. |
1205 | */ |
1206 | if (!ret) |
1207 | arch_ptrace_attach(child); |
1208 | goto out_put_task_struct; |
1209 | } |
1210 | |
1211 | ret = ptrace_check_attach(child, request == PTRACE_KILL || |
1212 | request == PTRACE_INTERRUPT); |
1213 | if (!ret) { |
1214 | ret = compat_arch_ptrace(child, request, addr, data); |
1215 | if (ret || request != PTRACE_DETACH) |
1216 | ptrace_unfreeze_traced(child); |
1217 | } |
1218 | |
1219 | out_put_task_struct: |
1220 | put_task_struct(child); |
1221 | out: |
1222 | return ret; |
1223 | } |
1224 | #endif /* CONFIG_COMPAT */ |
1225 |
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