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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/*
32 * ptrace a task: make the debugger its new parent and
33 * move it to the ptrace list.
34 *
35 * Must be called with the tasklist lock write-held.
36 */
37void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
38{
39 BUG_ON(!list_empty(&child->ptrace_entry));
40 list_add(&child->ptrace_entry, &new_parent->ptraced);
41 child->parent = new_parent;
42}
43
44/**
45 * __ptrace_unlink - unlink ptracee and restore its execution state
46 * @child: ptracee to be unlinked
47 *
48 * Remove @child from the ptrace list, move it back to the original parent,
49 * and restore the execution state so that it conforms to the group stop
50 * state.
51 *
52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
55 * If the ptracer is exiting, the ptracee can be in any state.
56 *
57 * After detach, the ptracee should be in a state which conforms to the
58 * group stop. If the group is stopped or in the process of stopping, the
59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
60 * up from TASK_TRACED.
61 *
62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
64 * to but in the opposite direction of what happens while attaching to a
65 * stopped task. However, in this direction, the intermediate RUNNING
66 * state is not hidden even from the current ptracer and if it immediately
67 * re-attaches and performs a WNOHANG wait(2), it may fail.
68 *
69 * CONTEXT:
70 * write_lock_irq(tasklist_lock)
71 */
72void __ptrace_unlink(struct task_struct *child)
73{
74 BUG_ON(!child->ptrace);
75
76 child->parent = child->real_parent;
77 list_del_init(&child->ptrace_entry);
78
79 spin_lock(&child->sighand->siglock);
80 child->ptrace = 0;
81 /*
82 * Clear all pending traps and TRAPPING. TRAPPING should be
83 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
84 */
85 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
86 task_clear_jobctl_trapping(child);
87
88 /*
89 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
90 * @child isn't dead.
91 */
92 if (!(child->flags & PF_EXITING) &&
93 (child->signal->flags & SIGNAL_STOP_STOPPED ||
94 child->signal->group_stop_count)) {
95 child->jobctl |= JOBCTL_STOP_PENDING;
96
97 /*
98 * This is only possible if this thread was cloned by the
99 * traced task running in the stopped group, set the signal
100 * for the future reports.
101 * FIXME: we should change ptrace_init_task() to handle this
102 * case.
103 */
104 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
105 child->jobctl |= SIGSTOP;
106 }
107
108 /*
109 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
110 * @child in the butt. Note that @resume should be used iff @child
111 * is in TASK_TRACED; otherwise, we might unduly disrupt
112 * TASK_KILLABLE sleeps.
113 */
114 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
115 ptrace_signal_wake_up(child, true);
116
117 spin_unlock(&child->sighand->siglock);
118}
119
120/* Ensure that nothing can wake it up, even SIGKILL */
121static bool ptrace_freeze_traced(struct task_struct *task)
122{
123 bool ret = false;
124
125 /* Lockless, nobody but us can set this flag */
126 if (task->jobctl & JOBCTL_LISTENING)
127 return ret;
128
129 spin_lock_irq(&task->sighand->siglock);
130 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
131 task->state = __TASK_TRACED;
132 ret = true;
133 }
134 spin_unlock_irq(&task->sighand->siglock);
135
136 return ret;
137}
138
139static void ptrace_unfreeze_traced(struct task_struct *task)
140{
141 if (task->state != __TASK_TRACED)
142 return;
143
144 WARN_ON(!task->ptrace || task->parent != current);
145
146 spin_lock_irq(&task->sighand->siglock);
147 if (__fatal_signal_pending(task))
148 wake_up_state(task, __TASK_TRACED);
149 else
150 task->state = TASK_TRACED;
151 spin_unlock_irq(&task->sighand->siglock);
152}
153
154/**
155 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
156 * @child: ptracee to check for
157 * @ignore_state: don't check whether @child is currently %TASK_TRACED
158 *
159 * Check whether @child is being ptraced by %current and ready for further
160 * ptrace operations. If @ignore_state is %false, @child also should be in
161 * %TASK_TRACED state and on return the child is guaranteed to be traced
162 * and not executing. If @ignore_state is %true, @child can be in any
163 * state.
164 *
165 * CONTEXT:
166 * Grabs and releases tasklist_lock and @child->sighand->siglock.
167 *
168 * RETURNS:
169 * 0 on success, -ESRCH if %child is not ready.
170 */
171static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
172{
173 int ret = -ESRCH;
174
175 /*
176 * We take the read lock around doing both checks to close a
177 * possible race where someone else was tracing our child and
178 * detached between these two checks. After this locked check,
179 * we are sure that this is our traced child and that can only
180 * be changed by us so it's not changing right after this.
181 */
182 read_lock(&tasklist_lock);
183 if (child->ptrace && child->parent == current) {
184 WARN_ON(child->state == __TASK_TRACED);
185 /*
186 * child->sighand can't be NULL, release_task()
187 * does ptrace_unlink() before __exit_signal().
188 */
189 if (ignore_state || ptrace_freeze_traced(child))
190 ret = 0;
191 }
192 read_unlock(&tasklist_lock);
193
194 if (!ret && !ignore_state) {
195 if (!wait_task_inactive(child, __TASK_TRACED)) {
196 /*
197 * This can only happen if may_ptrace_stop() fails and
198 * ptrace_stop() changes ->state back to TASK_RUNNING,
199 * so we should not worry about leaking __TASK_TRACED.
200 */
201 WARN_ON(child->state == __TASK_TRACED);
202 ret = -ESRCH;
203 }
204 }
205
206 return ret;
207}
208
209static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
210{
211 if (mode & PTRACE_MODE_NOAUDIT)
212 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
213 else
214 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
215}
216
217/* Returns 0 on success, -errno on denial. */
218static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
219{
220 const struct cred *cred = current_cred(), *tcred;
221 int dumpable = 0;
222 kuid_t caller_uid;
223 kgid_t caller_gid;
224
225 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
226 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
227 return -EPERM;
228 }
229
230 /* May we inspect the given task?
231 * This check is used both for attaching with ptrace
232 * and for allowing access to sensitive information in /proc.
233 *
234 * ptrace_attach denies several cases that /proc allows
235 * because setting up the necessary parent/child relationship
236 * or halting the specified task is impossible.
237 */
238
239 /* Don't let security modules deny introspection */
240 if (same_thread_group(task, current))
241 return 0;
242 rcu_read_lock();
243 if (mode & PTRACE_MODE_FSCREDS) {
244 caller_uid = cred->fsuid;
245 caller_gid = cred->fsgid;
246 } else {
247 /*
248 * Using the euid would make more sense here, but something
249 * in userland might rely on the old behavior, and this
250 * shouldn't be a security problem since
251 * PTRACE_MODE_REALCREDS implies that the caller explicitly
252 * used a syscall that requests access to another process
253 * (and not a filesystem syscall to procfs).
254 */
255 caller_uid = cred->uid;
256 caller_gid = cred->gid;
257 }
258 tcred = __task_cred(task);
259 if (uid_eq(caller_uid, tcred->euid) &&
260 uid_eq(caller_uid, tcred->suid) &&
261 uid_eq(caller_uid, tcred->uid) &&
262 gid_eq(caller_gid, tcred->egid) &&
263 gid_eq(caller_gid, tcred->sgid) &&
264 gid_eq(caller_gid, tcred->gid))
265 goto ok;
266 if (ptrace_has_cap(tcred->user_ns, mode))
267 goto ok;
268 rcu_read_unlock();
269 return -EPERM;
270ok:
271 rcu_read_unlock();
272 smp_rmb();
273 if (task->mm)
274 dumpable = get_dumpable(task->mm);
275 rcu_read_lock();
276 if (dumpable != SUID_DUMP_USER &&
277 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
278 rcu_read_unlock();
279 return -EPERM;
280 }
281 rcu_read_unlock();
282
283 return security_ptrace_access_check(task, mode);
284}
285
286bool ptrace_may_access(struct task_struct *task, unsigned int mode)
287{
288 int err;
289 task_lock(task);
290 err = __ptrace_may_access(task, mode);
291 task_unlock(task);
292 return !err;
293}
294
295static int ptrace_attach(struct task_struct *task, long request,
296 unsigned long addr,
297 unsigned long flags)
298{
299 bool seize = (request == PTRACE_SEIZE);
300 int retval;
301
302 retval = -EIO;
303 if (seize) {
304 if (addr != 0)
305 goto out;
306 if (flags & ~(unsigned long)PTRACE_O_MASK)
307 goto out;
308 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
309 } else {
310 flags = PT_PTRACED;
311 }
312
313 audit_ptrace(task);
314
315 retval = -EPERM;
316 if (unlikely(task->flags & PF_KTHREAD))
317 goto out;
318 if (same_thread_group(task, current))
319 goto out;
320
321 /*
322 * Protect exec's credential calculations against our interference;
323 * SUID, SGID and LSM creds get determined differently
324 * under ptrace.
325 */
326 retval = -ERESTARTNOINTR;
327 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
328 goto out;
329
330 task_lock(task);
331 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
332 task_unlock(task);
333 if (retval)
334 goto unlock_creds;
335
336 write_lock_irq(&tasklist_lock);
337 retval = -EPERM;
338 if (unlikely(task->exit_state))
339 goto unlock_tasklist;
340 if (task->ptrace)
341 goto unlock_tasklist;
342
343 if (seize)
344 flags |= PT_SEIZED;
345 rcu_read_lock();
346 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
347 flags |= PT_PTRACE_CAP;
348 rcu_read_unlock();
349 task->ptrace = flags;
350
351 __ptrace_link(task, current);
352
353 /* SEIZE doesn't trap tracee on attach */
354 if (!seize)
355 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
356
357 spin_lock(&task->sighand->siglock);
358
359 /*
360 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
361 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
362 * will be cleared if the child completes the transition or any
363 * event which clears the group stop states happens. We'll wait
364 * for the transition to complete before returning from this
365 * function.
366 *
367 * This hides STOPPED -> RUNNING -> TRACED transition from the
368 * attaching thread but a different thread in the same group can
369 * still observe the transient RUNNING state. IOW, if another
370 * thread's WNOHANG wait(2) on the stopped tracee races against
371 * ATTACH, the wait(2) may fail due to the transient RUNNING.
372 *
373 * The following task_is_stopped() test is safe as both transitions
374 * in and out of STOPPED are protected by siglock.
375 */
376 if (task_is_stopped(task) &&
377 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
378 signal_wake_up_state(task, __TASK_STOPPED);
379
380 spin_unlock(&task->sighand->siglock);
381
382 retval = 0;
383unlock_tasklist:
384 write_unlock_irq(&tasklist_lock);
385unlock_creds:
386 mutex_unlock(&task->signal->cred_guard_mutex);
387out:
388 if (!retval) {
389 /*
390 * We do not bother to change retval or clear JOBCTL_TRAPPING
391 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
392 * not return to user-mode, it will exit and clear this bit in
393 * __ptrace_unlink() if it wasn't already cleared by the tracee;
394 * and until then nobody can ptrace this task.
395 */
396 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
397 proc_ptrace_connector(task, PTRACE_ATTACH);
398 }
399
400 return retval;
401}
402
403/**
404 * ptrace_traceme -- helper for PTRACE_TRACEME
405 *
406 * Performs checks and sets PT_PTRACED.
407 * Should be used by all ptrace implementations for PTRACE_TRACEME.
408 */
409static int ptrace_traceme(void)
410{
411 int ret = -EPERM;
412
413 write_lock_irq(&tasklist_lock);
414 /* Are we already being traced? */
415 if (!current->ptrace) {
416 ret = security_ptrace_traceme(current->parent);
417 /*
418 * Check PF_EXITING to ensure ->real_parent has not passed
419 * exit_ptrace(). Otherwise we don't report the error but
420 * pretend ->real_parent untraces us right after return.
421 */
422 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
423 current->ptrace = PT_PTRACED;
424 __ptrace_link(current, current->real_parent);
425 }
426 }
427 write_unlock_irq(&tasklist_lock);
428
429 return ret;
430}
431
432/*
433 * Called with irqs disabled, returns true if childs should reap themselves.
434 */
435static int ignoring_children(struct sighand_struct *sigh)
436{
437 int ret;
438 spin_lock(&sigh->siglock);
439 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
440 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
441 spin_unlock(&sigh->siglock);
442 return ret;
443}
444
445/*
446 * Called with tasklist_lock held for writing.
447 * Unlink a traced task, and clean it up if it was a traced zombie.
448 * Return true if it needs to be reaped with release_task().
449 * (We can't call release_task() here because we already hold tasklist_lock.)
450 *
451 * If it's a zombie, our attachedness prevented normal parent notification
452 * or self-reaping. Do notification now if it would have happened earlier.
453 * If it should reap itself, return true.
454 *
455 * If it's our own child, there is no notification to do. But if our normal
456 * children self-reap, then this child was prevented by ptrace and we must
457 * reap it now, in that case we must also wake up sub-threads sleeping in
458 * do_wait().
459 */
460static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
461{
462 bool dead;
463
464 __ptrace_unlink(p);
465
466 if (p->exit_state != EXIT_ZOMBIE)
467 return false;
468
469 dead = !thread_group_leader(p);
470
471 if (!dead && thread_group_empty(p)) {
472 if (!same_thread_group(p->real_parent, tracer))
473 dead = do_notify_parent(p, p->exit_signal);
474 else if (ignoring_children(tracer->sighand)) {
475 __wake_up_parent(p, tracer);
476 dead = true;
477 }
478 }
479 /* Mark it as in the process of being reaped. */
480 if (dead)
481 p->exit_state = EXIT_DEAD;
482 return dead;
483}
484
485static int ptrace_detach(struct task_struct *child, unsigned int data)
486{
487 if (!valid_signal(data))
488 return -EIO;
489
490 /* Architecture-specific hardware disable .. */
491 ptrace_disable(child);
492 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
493
494 write_lock_irq(&tasklist_lock);
495 /*
496 * We rely on ptrace_freeze_traced(). It can't be killed and
497 * untraced by another thread, it can't be a zombie.
498 */
499 WARN_ON(!child->ptrace || child->exit_state);
500 /*
501 * tasklist_lock avoids the race with wait_task_stopped(), see
502 * the comment in ptrace_resume().
503 */
504 child->exit_code = data;
505 __ptrace_detach(current, child);
506 write_unlock_irq(&tasklist_lock);
507
508 proc_ptrace_connector(child, PTRACE_DETACH);
509
510 return 0;
511}
512
513/*
514 * Detach all tasks we were using ptrace on. Called with tasklist held
515 * for writing.
516 */
517void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
518{
519 struct task_struct *p, *n;
520
521 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
522 if (unlikely(p->ptrace & PT_EXITKILL))
523 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
524
525 if (__ptrace_detach(tracer, p))
526 list_add(&p->ptrace_entry, dead);
527 }
528}
529
530int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
531{
532 int copied = 0;
533
534 while (len > 0) {
535 char buf[128];
536 int this_len, retval;
537
538 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
539 retval = access_process_vm(tsk, src, buf, this_len, 0);
540 if (!retval) {
541 if (copied)
542 break;
543 return -EIO;
544 }
545 if (copy_to_user(dst, buf, retval))
546 return -EFAULT;
547 copied += retval;
548 src += retval;
549 dst += retval;
550 len -= retval;
551 }
552 return copied;
553}
554
555int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
556{
557 int copied = 0;
558
559 while (len > 0) {
560 char buf[128];
561 int this_len, retval;
562
563 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
564 if (copy_from_user(buf, src, this_len))
565 return -EFAULT;
566 retval = access_process_vm(tsk, dst, buf, this_len, 1);
567 if (!retval) {
568 if (copied)
569 break;
570 return -EIO;
571 }
572 copied += retval;
573 src += retval;
574 dst += retval;
575 len -= retval;
576 }
577 return copied;
578}
579
580static int ptrace_setoptions(struct task_struct *child, unsigned long data)
581{
582 unsigned flags;
583
584 if (data & ~(unsigned long)PTRACE_O_MASK)
585 return -EINVAL;
586
587 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
588 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
589 !config_enabled(CONFIG_SECCOMP))
590 return -EINVAL;
591
592 if (!capable(CAP_SYS_ADMIN))
593 return -EPERM;
594
595 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
596 current->ptrace & PT_SUSPEND_SECCOMP)
597 return -EPERM;
598 }
599
600 /* Avoid intermediate state when all opts are cleared */
601 flags = child->ptrace;
602 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
603 flags |= (data << PT_OPT_FLAG_SHIFT);
604 child->ptrace = flags;
605
606 return 0;
607}
608
609static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
610{
611 unsigned long flags;
612 int error = -ESRCH;
613
614 if (lock_task_sighand(child, &flags)) {
615 error = -EINVAL;
616 if (likely(child->last_siginfo != NULL)) {
617 *info = *child->last_siginfo;
618 error = 0;
619 }
620 unlock_task_sighand(child, &flags);
621 }
622 return error;
623}
624
625static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
626{
627 unsigned long flags;
628 int error = -ESRCH;
629
630 if (lock_task_sighand(child, &flags)) {
631 error = -EINVAL;
632 if (likely(child->last_siginfo != NULL)) {
633 *child->last_siginfo = *info;
634 error = 0;
635 }
636 unlock_task_sighand(child, &flags);
637 }
638 return error;
639}
640
641static int ptrace_peek_siginfo(struct task_struct *child,
642 unsigned long addr,
643 unsigned long data)
644{
645 struct ptrace_peeksiginfo_args arg;
646 struct sigpending *pending;
647 struct sigqueue *q;
648 int ret, i;
649
650 ret = copy_from_user(&arg, (void __user *) addr,
651 sizeof(struct ptrace_peeksiginfo_args));
652 if (ret)
653 return -EFAULT;
654
655 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
656 return -EINVAL; /* unknown flags */
657
658 if (arg.nr < 0)
659 return -EINVAL;
660
661 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
662 pending = &child->signal->shared_pending;
663 else
664 pending = &child->pending;
665
666 for (i = 0; i < arg.nr; ) {
667 siginfo_t info;
668 s32 off = arg.off + i;
669
670 spin_lock_irq(&child->sighand->siglock);
671 list_for_each_entry(q, &pending->list, list) {
672 if (!off--) {
673 copy_siginfo(&info, &q->info);
674 break;
675 }
676 }
677 spin_unlock_irq(&child->sighand->siglock);
678
679 if (off >= 0) /* beyond the end of the list */
680 break;
681
682#ifdef CONFIG_COMPAT
683 if (unlikely(in_compat_syscall())) {
684 compat_siginfo_t __user *uinfo = compat_ptr(data);
685
686 if (copy_siginfo_to_user32(uinfo, &info) ||
687 __put_user(info.si_code, &uinfo->si_code)) {
688 ret = -EFAULT;
689 break;
690 }
691
692 } else
693#endif
694 {
695 siginfo_t __user *uinfo = (siginfo_t __user *) data;
696
697 if (copy_siginfo_to_user(uinfo, &info) ||
698 __put_user(info.si_code, &uinfo->si_code)) {
699 ret = -EFAULT;
700 break;
701 }
702 }
703
704 data += sizeof(siginfo_t);
705 i++;
706
707 if (signal_pending(current))
708 break;
709
710 cond_resched();
711 }
712
713 if (i > 0)
714 return i;
715
716 return ret;
717}
718
719#ifdef PTRACE_SINGLESTEP
720#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
721#else
722#define is_singlestep(request) 0
723#endif
724
725#ifdef PTRACE_SINGLEBLOCK
726#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
727#else
728#define is_singleblock(request) 0
729#endif
730
731#ifdef PTRACE_SYSEMU
732#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
733#else
734#define is_sysemu_singlestep(request) 0
735#endif
736
737static int ptrace_resume(struct task_struct *child, long request,
738 unsigned long data)
739{
740 bool need_siglock;
741
742 if (!valid_signal(data))
743 return -EIO;
744
745 if (request == PTRACE_SYSCALL)
746 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
747 else
748 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
749
750#ifdef TIF_SYSCALL_EMU
751 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
752 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
753 else
754 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
755#endif
756
757 if (is_singleblock(request)) {
758 if (unlikely(!arch_has_block_step()))
759 return -EIO;
760 user_enable_block_step(child);
761 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
762 if (unlikely(!arch_has_single_step()))
763 return -EIO;
764 user_enable_single_step(child);
765 } else {
766 user_disable_single_step(child);
767 }
768
769 /*
770 * Change ->exit_code and ->state under siglock to avoid the race
771 * with wait_task_stopped() in between; a non-zero ->exit_code will
772 * wrongly look like another report from tracee.
773 *
774 * Note that we need siglock even if ->exit_code == data and/or this
775 * status was not reported yet, the new status must not be cleared by
776 * wait_task_stopped() after resume.
777 *
778 * If data == 0 we do not care if wait_task_stopped() reports the old
779 * status and clears the code too; this can't race with the tracee, it
780 * takes siglock after resume.
781 */
782 need_siglock = data && !thread_group_empty(current);
783 if (need_siglock)
784 spin_lock_irq(&child->sighand->siglock);
785 child->exit_code = data;
786 wake_up_state(child, __TASK_TRACED);
787 if (need_siglock)
788 spin_unlock_irq(&child->sighand->siglock);
789
790 return 0;
791}
792
793#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
794
795static const struct user_regset *
796find_regset(const struct user_regset_view *view, unsigned int type)
797{
798 const struct user_regset *regset;
799 int n;
800
801 for (n = 0; n < view->n; ++n) {
802 regset = view->regsets + n;
803 if (regset->core_note_type == type)
804 return regset;
805 }
806
807 return NULL;
808}
809
810static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
811 struct iovec *kiov)
812{
813 const struct user_regset_view *view = task_user_regset_view(task);
814 const struct user_regset *regset = find_regset(view, type);
815 int regset_no;
816
817 if (!regset || (kiov->iov_len % regset->size) != 0)
818 return -EINVAL;
819
820 regset_no = regset - view->regsets;
821 kiov->iov_len = min(kiov->iov_len,
822 (__kernel_size_t) (regset->n * regset->size));
823
824 if (req == PTRACE_GETREGSET)
825 return copy_regset_to_user(task, view, regset_no, 0,
826 kiov->iov_len, kiov->iov_base);
827 else
828 return copy_regset_from_user(task, view, regset_no, 0,
829 kiov->iov_len, kiov->iov_base);
830}
831
832/*
833 * This is declared in linux/regset.h and defined in machine-dependent
834 * code. We put the export here, near the primary machine-neutral use,
835 * to ensure no machine forgets it.
836 */
837EXPORT_SYMBOL_GPL(task_user_regset_view);
838#endif
839
840int ptrace_request(struct task_struct *child, long request,
841 unsigned long addr, unsigned long data)
842{
843 bool seized = child->ptrace & PT_SEIZED;
844 int ret = -EIO;
845 siginfo_t siginfo, *si;
846 void __user *datavp = (void __user *) data;
847 unsigned long __user *datalp = datavp;
848 unsigned long flags;
849
850 switch (request) {
851 case PTRACE_PEEKTEXT:
852 case PTRACE_PEEKDATA:
853 return generic_ptrace_peekdata(child, addr, data);
854 case PTRACE_POKETEXT:
855 case PTRACE_POKEDATA:
856 return generic_ptrace_pokedata(child, addr, data);
857
858#ifdef PTRACE_OLDSETOPTIONS
859 case PTRACE_OLDSETOPTIONS:
860#endif
861 case PTRACE_SETOPTIONS:
862 ret = ptrace_setoptions(child, data);
863 break;
864 case PTRACE_GETEVENTMSG:
865 ret = put_user(child->ptrace_message, datalp);
866 break;
867
868 case PTRACE_PEEKSIGINFO:
869 ret = ptrace_peek_siginfo(child, addr, data);
870 break;
871
872 case PTRACE_GETSIGINFO:
873 ret = ptrace_getsiginfo(child, &siginfo);
874 if (!ret)
875 ret = copy_siginfo_to_user(datavp, &siginfo);
876 break;
877
878 case PTRACE_SETSIGINFO:
879 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
880 ret = -EFAULT;
881 else
882 ret = ptrace_setsiginfo(child, &siginfo);
883 break;
884
885 case PTRACE_GETSIGMASK:
886 if (addr != sizeof(sigset_t)) {
887 ret = -EINVAL;
888 break;
889 }
890
891 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
892 ret = -EFAULT;
893 else
894 ret = 0;
895
896 break;
897
898 case PTRACE_SETSIGMASK: {
899 sigset_t new_set;
900
901 if (addr != sizeof(sigset_t)) {
902 ret = -EINVAL;
903 break;
904 }
905
906 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
907 ret = -EFAULT;
908 break;
909 }
910
911 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
912
913 /*
914 * Every thread does recalc_sigpending() after resume, so
915 * retarget_shared_pending() and recalc_sigpending() are not
916 * called here.
917 */
918 spin_lock_irq(&child->sighand->siglock);
919 child->blocked = new_set;
920 spin_unlock_irq(&child->sighand->siglock);
921
922 ret = 0;
923 break;
924 }
925
926 case PTRACE_INTERRUPT:
927 /*
928 * Stop tracee without any side-effect on signal or job
929 * control. At least one trap is guaranteed to happen
930 * after this request. If @child is already trapped, the
931 * current trap is not disturbed and another trap will
932 * happen after the current trap is ended with PTRACE_CONT.
933 *
934 * The actual trap might not be PTRACE_EVENT_STOP trap but
935 * the pending condition is cleared regardless.
936 */
937 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
938 break;
939
940 /*
941 * INTERRUPT doesn't disturb existing trap sans one
942 * exception. If ptracer issued LISTEN for the current
943 * STOP, this INTERRUPT should clear LISTEN and re-trap
944 * tracee into STOP.
945 */
946 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
947 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
948
949 unlock_task_sighand(child, &flags);
950 ret = 0;
951 break;
952
953 case PTRACE_LISTEN:
954 /*
955 * Listen for events. Tracee must be in STOP. It's not
956 * resumed per-se but is not considered to be in TRACED by
957 * wait(2) or ptrace(2). If an async event (e.g. group
958 * stop state change) happens, tracee will enter STOP trap
959 * again. Alternatively, ptracer can issue INTERRUPT to
960 * finish listening and re-trap tracee into STOP.
961 */
962 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
963 break;
964
965 si = child->last_siginfo;
966 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
967 child->jobctl |= JOBCTL_LISTENING;
968 /*
969 * If NOTIFY is set, it means event happened between
970 * start of this trap and now. Trigger re-trap.
971 */
972 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
973 ptrace_signal_wake_up(child, true);
974 ret = 0;
975 }
976 unlock_task_sighand(child, &flags);
977 break;
978
979 case PTRACE_DETACH: /* detach a process that was attached. */
980 ret = ptrace_detach(child, data);
981 break;
982
983#ifdef CONFIG_BINFMT_ELF_FDPIC
984 case PTRACE_GETFDPIC: {
985 struct mm_struct *mm = get_task_mm(child);
986 unsigned long tmp = 0;
987
988 ret = -ESRCH;
989 if (!mm)
990 break;
991
992 switch (addr) {
993 case PTRACE_GETFDPIC_EXEC:
994 tmp = mm->context.exec_fdpic_loadmap;
995 break;
996 case PTRACE_GETFDPIC_INTERP:
997 tmp = mm->context.interp_fdpic_loadmap;
998 break;
999 default:
1000 break;
1001 }
1002 mmput(mm);
1003
1004 ret = put_user(tmp, datalp);
1005 break;
1006 }
1007#endif
1008
1009#ifdef PTRACE_SINGLESTEP
1010 case PTRACE_SINGLESTEP:
1011#endif
1012#ifdef PTRACE_SINGLEBLOCK
1013 case PTRACE_SINGLEBLOCK:
1014#endif
1015#ifdef PTRACE_SYSEMU
1016 case PTRACE_SYSEMU:
1017 case PTRACE_SYSEMU_SINGLESTEP:
1018#endif
1019 case PTRACE_SYSCALL:
1020 case PTRACE_CONT:
1021 return ptrace_resume(child, request, data);
1022
1023 case PTRACE_KILL:
1024 if (child->exit_state) /* already dead */
1025 return 0;
1026 return ptrace_resume(child, request, SIGKILL);
1027
1028#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1029 case PTRACE_GETREGSET:
1030 case PTRACE_SETREGSET: {
1031 struct iovec kiov;
1032 struct iovec __user *uiov = datavp;
1033
1034 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1035 return -EFAULT;
1036
1037 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1038 __get_user(kiov.iov_len, &uiov->iov_len))
1039 return -EFAULT;
1040
1041 ret = ptrace_regset(child, request, addr, &kiov);
1042 if (!ret)
1043 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1044 break;
1045 }
1046#endif
1047
1048 case PTRACE_SECCOMP_GET_FILTER:
1049 ret = seccomp_get_filter(child, addr, datavp);
1050 break;
1051
1052 default:
1053 break;
1054 }
1055
1056 return ret;
1057}
1058
1059static struct task_struct *ptrace_get_task_struct(pid_t pid)
1060{
1061 struct task_struct *child;
1062
1063 rcu_read_lock();
1064 child = find_task_by_vpid(pid);
1065 if (child)
1066 get_task_struct(child);
1067 rcu_read_unlock();
1068
1069 if (!child)
1070 return ERR_PTR(-ESRCH);
1071 return child;
1072}
1073
1074#ifndef arch_ptrace_attach
1075#define arch_ptrace_attach(child) do { } while (0)
1076#endif
1077
1078SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1079 unsigned long, data)
1080{
1081 struct task_struct *child;
1082 long ret;
1083
1084 if (request == PTRACE_TRACEME) {
1085 ret = ptrace_traceme();
1086 if (!ret)
1087 arch_ptrace_attach(current);
1088 goto out;
1089 }
1090
1091 child = ptrace_get_task_struct(pid);
1092 if (IS_ERR(child)) {
1093 ret = PTR_ERR(child);
1094 goto out;
1095 }
1096
1097 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1098 ret = ptrace_attach(child, request, addr, data);
1099 /*
1100 * Some architectures need to do book-keeping after
1101 * a ptrace attach.
1102 */
1103 if (!ret)
1104 arch_ptrace_attach(child);
1105 goto out_put_task_struct;
1106 }
1107
1108 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1109 request == PTRACE_INTERRUPT);
1110 if (ret < 0)
1111 goto out_put_task_struct;
1112
1113 ret = arch_ptrace(child, request, addr, data);
1114 if (ret || request != PTRACE_DETACH)
1115 ptrace_unfreeze_traced(child);
1116
1117 out_put_task_struct:
1118 put_task_struct(child);
1119 out:
1120 return ret;
1121}
1122
1123int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1124 unsigned long data)
1125{
1126 unsigned long tmp;
1127 int copied;
1128
1129 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1130 if (copied != sizeof(tmp))
1131 return -EIO;
1132 return put_user(tmp, (unsigned long __user *)data);
1133}
1134
1135int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1136 unsigned long data)
1137{
1138 int copied;
1139
1140 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1141 return (copied == sizeof(data)) ? 0 : -EIO;
1142}
1143
1144#if defined CONFIG_COMPAT
1145
1146int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1147 compat_ulong_t addr, compat_ulong_t data)
1148{
1149 compat_ulong_t __user *datap = compat_ptr(data);
1150 compat_ulong_t word;
1151 siginfo_t siginfo;
1152 int ret;
1153
1154 switch (request) {
1155 case PTRACE_PEEKTEXT:
1156 case PTRACE_PEEKDATA:
1157 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1158 if (ret != sizeof(word))
1159 ret = -EIO;
1160 else
1161 ret = put_user(word, datap);
1162 break;
1163
1164 case PTRACE_POKETEXT:
1165 case PTRACE_POKEDATA:
1166 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1167 ret = (ret != sizeof(data) ? -EIO : 0);
1168 break;
1169
1170 case PTRACE_GETEVENTMSG:
1171 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1172 break;
1173
1174 case PTRACE_GETSIGINFO:
1175 ret = ptrace_getsiginfo(child, &siginfo);
1176 if (!ret)
1177 ret = copy_siginfo_to_user32(
1178 (struct compat_siginfo __user *) datap,
1179 &siginfo);
1180 break;
1181
1182 case PTRACE_SETSIGINFO:
1183 memset(&siginfo, 0, sizeof siginfo);
1184 if (copy_siginfo_from_user32(
1185 &siginfo, (struct compat_siginfo __user *) datap))
1186 ret = -EFAULT;
1187 else
1188 ret = ptrace_setsiginfo(child, &siginfo);
1189 break;
1190#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1191 case PTRACE_GETREGSET:
1192 case PTRACE_SETREGSET:
1193 {
1194 struct iovec kiov;
1195 struct compat_iovec __user *uiov =
1196 (struct compat_iovec __user *) datap;
1197 compat_uptr_t ptr;
1198 compat_size_t len;
1199
1200 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1201 return -EFAULT;
1202
1203 if (__get_user(ptr, &uiov->iov_base) ||
1204 __get_user(len, &uiov->iov_len))
1205 return -EFAULT;
1206
1207 kiov.iov_base = compat_ptr(ptr);
1208 kiov.iov_len = len;
1209
1210 ret = ptrace_regset(child, request, addr, &kiov);
1211 if (!ret)
1212 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1213 break;
1214 }
1215#endif
1216
1217 default:
1218 ret = ptrace_request(child, request, addr, data);
1219 }
1220
1221 return ret;
1222}
1223
1224COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1225 compat_long_t, addr, compat_long_t, data)
1226{
1227 struct task_struct *child;
1228 long ret;
1229
1230 if (request == PTRACE_TRACEME) {
1231 ret = ptrace_traceme();
1232 goto out;
1233 }
1234
1235 child = ptrace_get_task_struct(pid);
1236 if (IS_ERR(child)) {
1237 ret = PTR_ERR(child);
1238 goto out;
1239 }
1240
1241 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1242 ret = ptrace_attach(child, request, addr, data);
1243 /*
1244 * Some architectures need to do book-keeping after
1245 * a ptrace attach.
1246 */
1247 if (!ret)
1248 arch_ptrace_attach(child);
1249 goto out_put_task_struct;
1250 }
1251
1252 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1253 request == PTRACE_INTERRUPT);
1254 if (!ret) {
1255 ret = compat_arch_ptrace(child, request, addr, data);
1256 if (ret || request != PTRACE_DETACH)
1257 ptrace_unfreeze_traced(child);
1258 }
1259
1260 out_put_task_struct:
1261 put_task_struct(child);
1262 out:
1263 return ret;
1264}
1265#endif /* CONFIG_COMPAT */
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/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/ptrace.h>
18#include <linux/security.h>
19#include <linux/signal.h>
20#include <linux/audit.h>
21#include <linux/pid_namespace.h>
22#include <linux/syscalls.h>
23#include <linux/uaccess.h>
24#include <linux/regset.h>
25#include <linux/hw_breakpoint.h>
26#include <linux/cn_proc.h>
27
28
29static int ptrace_trapping_sleep_fn(void *flags)
30{
31 schedule();
32 return 0;
33}
34
35/*
36 * ptrace a task: make the debugger its new parent and
37 * move it to the ptrace list.
38 *
39 * Must be called with the tasklist lock write-held.
40 */
41void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
42{
43 BUG_ON(!list_empty(&child->ptrace_entry));
44 list_add(&child->ptrace_entry, &new_parent->ptraced);
45 child->parent = new_parent;
46}
47
48/**
49 * __ptrace_unlink - unlink ptracee and restore its execution state
50 * @child: ptracee to be unlinked
51 *
52 * Remove @child from the ptrace list, move it back to the original parent,
53 * and restore the execution state so that it conforms to the group stop
54 * state.
55 *
56 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
57 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
58 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
59 * If the ptracer is exiting, the ptracee can be in any state.
60 *
61 * After detach, the ptracee should be in a state which conforms to the
62 * group stop. If the group is stopped or in the process of stopping, the
63 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
64 * up from TASK_TRACED.
65 *
66 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
67 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
68 * to but in the opposite direction of what happens while attaching to a
69 * stopped task. However, in this direction, the intermediate RUNNING
70 * state is not hidden even from the current ptracer and if it immediately
71 * re-attaches and performs a WNOHANG wait(2), it may fail.
72 *
73 * CONTEXT:
74 * write_lock_irq(tasklist_lock)
75 */
76void __ptrace_unlink(struct task_struct *child)
77{
78 BUG_ON(!child->ptrace);
79
80 child->ptrace = 0;
81 child->parent = child->real_parent;
82 list_del_init(&child->ptrace_entry);
83
84 spin_lock(&child->sighand->siglock);
85
86 /*
87 * Clear all pending traps and TRAPPING. TRAPPING should be
88 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
89 */
90 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
91 task_clear_jobctl_trapping(child);
92
93 /*
94 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
95 * @child isn't dead.
96 */
97 if (!(child->flags & PF_EXITING) &&
98 (child->signal->flags & SIGNAL_STOP_STOPPED ||
99 child->signal->group_stop_count))
100 child->jobctl |= JOBCTL_STOP_PENDING;
101
102 /*
103 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
104 * @child in the butt. Note that @resume should be used iff @child
105 * is in TASK_TRACED; otherwise, we might unduly disrupt
106 * TASK_KILLABLE sleeps.
107 */
108 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
109 signal_wake_up(child, task_is_traced(child));
110
111 spin_unlock(&child->sighand->siglock);
112}
113
114/**
115 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
116 * @child: ptracee to check for
117 * @ignore_state: don't check whether @child is currently %TASK_TRACED
118 *
119 * Check whether @child is being ptraced by %current and ready for further
120 * ptrace operations. If @ignore_state is %false, @child also should be in
121 * %TASK_TRACED state and on return the child is guaranteed to be traced
122 * and not executing. If @ignore_state is %true, @child can be in any
123 * state.
124 *
125 * CONTEXT:
126 * Grabs and releases tasklist_lock and @child->sighand->siglock.
127 *
128 * RETURNS:
129 * 0 on success, -ESRCH if %child is not ready.
130 */
131int ptrace_check_attach(struct task_struct *child, bool ignore_state)
132{
133 int ret = -ESRCH;
134
135 /*
136 * We take the read lock around doing both checks to close a
137 * possible race where someone else was tracing our child and
138 * detached between these two checks. After this locked check,
139 * we are sure that this is our traced child and that can only
140 * be changed by us so it's not changing right after this.
141 */
142 read_lock(&tasklist_lock);
143 if ((child->ptrace & PT_PTRACED) && child->parent == current) {
144 /*
145 * child->sighand can't be NULL, release_task()
146 * does ptrace_unlink() before __exit_signal().
147 */
148 spin_lock_irq(&child->sighand->siglock);
149 WARN_ON_ONCE(task_is_stopped(child));
150 if (ignore_state || (task_is_traced(child) &&
151 !(child->jobctl & JOBCTL_LISTENING)))
152 ret = 0;
153 spin_unlock_irq(&child->sighand->siglock);
154 }
155 read_unlock(&tasklist_lock);
156
157 if (!ret && !ignore_state)
158 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
159
160 /* All systems go.. */
161 return ret;
162}
163
164int __ptrace_may_access(struct task_struct *task, unsigned int mode)
165{
166 const struct cred *cred = current_cred(), *tcred;
167
168 /* May we inspect the given task?
169 * This check is used both for attaching with ptrace
170 * and for allowing access to sensitive information in /proc.
171 *
172 * ptrace_attach denies several cases that /proc allows
173 * because setting up the necessary parent/child relationship
174 * or halting the specified task is impossible.
175 */
176 int dumpable = 0;
177 /* Don't let security modules deny introspection */
178 if (task == current)
179 return 0;
180 rcu_read_lock();
181 tcred = __task_cred(task);
182 if (cred->user->user_ns == tcred->user->user_ns &&
183 (cred->uid == tcred->euid &&
184 cred->uid == tcred->suid &&
185 cred->uid == tcred->uid &&
186 cred->gid == tcred->egid &&
187 cred->gid == tcred->sgid &&
188 cred->gid == tcred->gid))
189 goto ok;
190 if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE))
191 goto ok;
192 rcu_read_unlock();
193 return -EPERM;
194ok:
195 rcu_read_unlock();
196 smp_rmb();
197 if (task->mm)
198 dumpable = get_dumpable(task->mm);
199 if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE))
200 return -EPERM;
201
202 return security_ptrace_access_check(task, mode);
203}
204
205bool ptrace_may_access(struct task_struct *task, unsigned int mode)
206{
207 int err;
208 task_lock(task);
209 err = __ptrace_may_access(task, mode);
210 task_unlock(task);
211 return !err;
212}
213
214static int ptrace_attach(struct task_struct *task, long request,
215 unsigned long flags)
216{
217 bool seize = (request == PTRACE_SEIZE);
218 int retval;
219
220 /*
221 * SEIZE will enable new ptrace behaviors which will be implemented
222 * gradually. SEIZE_DEVEL is used to prevent applications
223 * expecting full SEIZE behaviors trapping on kernel commits which
224 * are still in the process of implementing them.
225 *
226 * Only test programs for new ptrace behaviors being implemented
227 * should set SEIZE_DEVEL. If unset, SEIZE will fail with -EIO.
228 *
229 * Once SEIZE behaviors are completely implemented, this flag and
230 * the following test will be removed.
231 */
232 retval = -EIO;
233 if (seize && !(flags & PTRACE_SEIZE_DEVEL))
234 goto out;
235
236 audit_ptrace(task);
237
238 retval = -EPERM;
239 if (unlikely(task->flags & PF_KTHREAD))
240 goto out;
241 if (same_thread_group(task, current))
242 goto out;
243
244 /*
245 * Protect exec's credential calculations against our interference;
246 * interference; SUID, SGID and LSM creds get determined differently
247 * under ptrace.
248 */
249 retval = -ERESTARTNOINTR;
250 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
251 goto out;
252
253 task_lock(task);
254 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
255 task_unlock(task);
256 if (retval)
257 goto unlock_creds;
258
259 write_lock_irq(&tasklist_lock);
260 retval = -EPERM;
261 if (unlikely(task->exit_state))
262 goto unlock_tasklist;
263 if (task->ptrace)
264 goto unlock_tasklist;
265
266 task->ptrace = PT_PTRACED;
267 if (seize)
268 task->ptrace |= PT_SEIZED;
269 if (task_ns_capable(task, CAP_SYS_PTRACE))
270 task->ptrace |= PT_PTRACE_CAP;
271
272 __ptrace_link(task, current);
273
274 /* SEIZE doesn't trap tracee on attach */
275 if (!seize)
276 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
277
278 spin_lock(&task->sighand->siglock);
279
280 /*
281 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
282 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
283 * will be cleared if the child completes the transition or any
284 * event which clears the group stop states happens. We'll wait
285 * for the transition to complete before returning from this
286 * function.
287 *
288 * This hides STOPPED -> RUNNING -> TRACED transition from the
289 * attaching thread but a different thread in the same group can
290 * still observe the transient RUNNING state. IOW, if another
291 * thread's WNOHANG wait(2) on the stopped tracee races against
292 * ATTACH, the wait(2) may fail due to the transient RUNNING.
293 *
294 * The following task_is_stopped() test is safe as both transitions
295 * in and out of STOPPED are protected by siglock.
296 */
297 if (task_is_stopped(task) &&
298 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
299 signal_wake_up(task, 1);
300
301 spin_unlock(&task->sighand->siglock);
302
303 retval = 0;
304unlock_tasklist:
305 write_unlock_irq(&tasklist_lock);
306unlock_creds:
307 mutex_unlock(&task->signal->cred_guard_mutex);
308out:
309 if (!retval) {
310 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
311 ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE);
312 proc_ptrace_connector(task, PTRACE_ATTACH);
313 }
314
315 return retval;
316}
317
318/**
319 * ptrace_traceme -- helper for PTRACE_TRACEME
320 *
321 * Performs checks and sets PT_PTRACED.
322 * Should be used by all ptrace implementations for PTRACE_TRACEME.
323 */
324static int ptrace_traceme(void)
325{
326 int ret = -EPERM;
327
328 write_lock_irq(&tasklist_lock);
329 /* Are we already being traced? */
330 if (!current->ptrace) {
331 ret = security_ptrace_traceme(current->parent);
332 /*
333 * Check PF_EXITING to ensure ->real_parent has not passed
334 * exit_ptrace(). Otherwise we don't report the error but
335 * pretend ->real_parent untraces us right after return.
336 */
337 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
338 current->ptrace = PT_PTRACED;
339 __ptrace_link(current, current->real_parent);
340 }
341 }
342 write_unlock_irq(&tasklist_lock);
343
344 return ret;
345}
346
347/*
348 * Called with irqs disabled, returns true if childs should reap themselves.
349 */
350static int ignoring_children(struct sighand_struct *sigh)
351{
352 int ret;
353 spin_lock(&sigh->siglock);
354 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
355 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
356 spin_unlock(&sigh->siglock);
357 return ret;
358}
359
360/*
361 * Called with tasklist_lock held for writing.
362 * Unlink a traced task, and clean it up if it was a traced zombie.
363 * Return true if it needs to be reaped with release_task().
364 * (We can't call release_task() here because we already hold tasklist_lock.)
365 *
366 * If it's a zombie, our attachedness prevented normal parent notification
367 * or self-reaping. Do notification now if it would have happened earlier.
368 * If it should reap itself, return true.
369 *
370 * If it's our own child, there is no notification to do. But if our normal
371 * children self-reap, then this child was prevented by ptrace and we must
372 * reap it now, in that case we must also wake up sub-threads sleeping in
373 * do_wait().
374 */
375static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
376{
377 bool dead;
378
379 __ptrace_unlink(p);
380
381 if (p->exit_state != EXIT_ZOMBIE)
382 return false;
383
384 dead = !thread_group_leader(p);
385
386 if (!dead && thread_group_empty(p)) {
387 if (!same_thread_group(p->real_parent, tracer))
388 dead = do_notify_parent(p, p->exit_signal);
389 else if (ignoring_children(tracer->sighand)) {
390 __wake_up_parent(p, tracer);
391 dead = true;
392 }
393 }
394 /* Mark it as in the process of being reaped. */
395 if (dead)
396 p->exit_state = EXIT_DEAD;
397 return dead;
398}
399
400static int ptrace_detach(struct task_struct *child, unsigned int data)
401{
402 bool dead = false;
403
404 if (!valid_signal(data))
405 return -EIO;
406
407 /* Architecture-specific hardware disable .. */
408 ptrace_disable(child);
409 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
410
411 write_lock_irq(&tasklist_lock);
412 /*
413 * This child can be already killed. Make sure de_thread() or
414 * our sub-thread doing do_wait() didn't do release_task() yet.
415 */
416 if (child->ptrace) {
417 child->exit_code = data;
418 dead = __ptrace_detach(current, child);
419 }
420 write_unlock_irq(&tasklist_lock);
421
422 proc_ptrace_connector(child, PTRACE_DETACH);
423 if (unlikely(dead))
424 release_task(child);
425
426 return 0;
427}
428
429/*
430 * Detach all tasks we were using ptrace on. Called with tasklist held
431 * for writing, and returns with it held too. But note it can release
432 * and reacquire the lock.
433 */
434void exit_ptrace(struct task_struct *tracer)
435 __releases(&tasklist_lock)
436 __acquires(&tasklist_lock)
437{
438 struct task_struct *p, *n;
439 LIST_HEAD(ptrace_dead);
440
441 if (likely(list_empty(&tracer->ptraced)))
442 return;
443
444 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
445 if (__ptrace_detach(tracer, p))
446 list_add(&p->ptrace_entry, &ptrace_dead);
447 }
448
449 write_unlock_irq(&tasklist_lock);
450 BUG_ON(!list_empty(&tracer->ptraced));
451
452 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
453 list_del_init(&p->ptrace_entry);
454 release_task(p);
455 }
456
457 write_lock_irq(&tasklist_lock);
458}
459
460int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
461{
462 int copied = 0;
463
464 while (len > 0) {
465 char buf[128];
466 int this_len, retval;
467
468 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
469 retval = access_process_vm(tsk, src, buf, this_len, 0);
470 if (!retval) {
471 if (copied)
472 break;
473 return -EIO;
474 }
475 if (copy_to_user(dst, buf, retval))
476 return -EFAULT;
477 copied += retval;
478 src += retval;
479 dst += retval;
480 len -= retval;
481 }
482 return copied;
483}
484
485int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
486{
487 int copied = 0;
488
489 while (len > 0) {
490 char buf[128];
491 int this_len, retval;
492
493 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
494 if (copy_from_user(buf, src, this_len))
495 return -EFAULT;
496 retval = access_process_vm(tsk, dst, buf, this_len, 1);
497 if (!retval) {
498 if (copied)
499 break;
500 return -EIO;
501 }
502 copied += retval;
503 src += retval;
504 dst += retval;
505 len -= retval;
506 }
507 return copied;
508}
509
510static int ptrace_setoptions(struct task_struct *child, unsigned long data)
511{
512 child->ptrace &= ~PT_TRACE_MASK;
513
514 if (data & PTRACE_O_TRACESYSGOOD)
515 child->ptrace |= PT_TRACESYSGOOD;
516
517 if (data & PTRACE_O_TRACEFORK)
518 child->ptrace |= PT_TRACE_FORK;
519
520 if (data & PTRACE_O_TRACEVFORK)
521 child->ptrace |= PT_TRACE_VFORK;
522
523 if (data & PTRACE_O_TRACECLONE)
524 child->ptrace |= PT_TRACE_CLONE;
525
526 if (data & PTRACE_O_TRACEEXEC)
527 child->ptrace |= PT_TRACE_EXEC;
528
529 if (data & PTRACE_O_TRACEVFORKDONE)
530 child->ptrace |= PT_TRACE_VFORK_DONE;
531
532 if (data & PTRACE_O_TRACEEXIT)
533 child->ptrace |= PT_TRACE_EXIT;
534
535 return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
536}
537
538static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
539{
540 unsigned long flags;
541 int error = -ESRCH;
542
543 if (lock_task_sighand(child, &flags)) {
544 error = -EINVAL;
545 if (likely(child->last_siginfo != NULL)) {
546 *info = *child->last_siginfo;
547 error = 0;
548 }
549 unlock_task_sighand(child, &flags);
550 }
551 return error;
552}
553
554static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
555{
556 unsigned long flags;
557 int error = -ESRCH;
558
559 if (lock_task_sighand(child, &flags)) {
560 error = -EINVAL;
561 if (likely(child->last_siginfo != NULL)) {
562 *child->last_siginfo = *info;
563 error = 0;
564 }
565 unlock_task_sighand(child, &flags);
566 }
567 return error;
568}
569
570
571#ifdef PTRACE_SINGLESTEP
572#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
573#else
574#define is_singlestep(request) 0
575#endif
576
577#ifdef PTRACE_SINGLEBLOCK
578#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
579#else
580#define is_singleblock(request) 0
581#endif
582
583#ifdef PTRACE_SYSEMU
584#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
585#else
586#define is_sysemu_singlestep(request) 0
587#endif
588
589static int ptrace_resume(struct task_struct *child, long request,
590 unsigned long data)
591{
592 if (!valid_signal(data))
593 return -EIO;
594
595 if (request == PTRACE_SYSCALL)
596 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
597 else
598 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
599
600#ifdef TIF_SYSCALL_EMU
601 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
602 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
603 else
604 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
605#endif
606
607 if (is_singleblock(request)) {
608 if (unlikely(!arch_has_block_step()))
609 return -EIO;
610 user_enable_block_step(child);
611 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
612 if (unlikely(!arch_has_single_step()))
613 return -EIO;
614 user_enable_single_step(child);
615 } else {
616 user_disable_single_step(child);
617 }
618
619 child->exit_code = data;
620 wake_up_state(child, __TASK_TRACED);
621
622 return 0;
623}
624
625#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
626
627static const struct user_regset *
628find_regset(const struct user_regset_view *view, unsigned int type)
629{
630 const struct user_regset *regset;
631 int n;
632
633 for (n = 0; n < view->n; ++n) {
634 regset = view->regsets + n;
635 if (regset->core_note_type == type)
636 return regset;
637 }
638
639 return NULL;
640}
641
642static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
643 struct iovec *kiov)
644{
645 const struct user_regset_view *view = task_user_regset_view(task);
646 const struct user_regset *regset = find_regset(view, type);
647 int regset_no;
648
649 if (!regset || (kiov->iov_len % regset->size) != 0)
650 return -EINVAL;
651
652 regset_no = regset - view->regsets;
653 kiov->iov_len = min(kiov->iov_len,
654 (__kernel_size_t) (regset->n * regset->size));
655
656 if (req == PTRACE_GETREGSET)
657 return copy_regset_to_user(task, view, regset_no, 0,
658 kiov->iov_len, kiov->iov_base);
659 else
660 return copy_regset_from_user(task, view, regset_no, 0,
661 kiov->iov_len, kiov->iov_base);
662}
663
664#endif
665
666int ptrace_request(struct task_struct *child, long request,
667 unsigned long addr, unsigned long data)
668{
669 bool seized = child->ptrace & PT_SEIZED;
670 int ret = -EIO;
671 siginfo_t siginfo, *si;
672 void __user *datavp = (void __user *) data;
673 unsigned long __user *datalp = datavp;
674 unsigned long flags;
675
676 switch (request) {
677 case PTRACE_PEEKTEXT:
678 case PTRACE_PEEKDATA:
679 return generic_ptrace_peekdata(child, addr, data);
680 case PTRACE_POKETEXT:
681 case PTRACE_POKEDATA:
682 return generic_ptrace_pokedata(child, addr, data);
683
684#ifdef PTRACE_OLDSETOPTIONS
685 case PTRACE_OLDSETOPTIONS:
686#endif
687 case PTRACE_SETOPTIONS:
688 ret = ptrace_setoptions(child, data);
689 break;
690 case PTRACE_GETEVENTMSG:
691 ret = put_user(child->ptrace_message, datalp);
692 break;
693
694 case PTRACE_GETSIGINFO:
695 ret = ptrace_getsiginfo(child, &siginfo);
696 if (!ret)
697 ret = copy_siginfo_to_user(datavp, &siginfo);
698 break;
699
700 case PTRACE_SETSIGINFO:
701 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
702 ret = -EFAULT;
703 else
704 ret = ptrace_setsiginfo(child, &siginfo);
705 break;
706
707 case PTRACE_INTERRUPT:
708 /*
709 * Stop tracee without any side-effect on signal or job
710 * control. At least one trap is guaranteed to happen
711 * after this request. If @child is already trapped, the
712 * current trap is not disturbed and another trap will
713 * happen after the current trap is ended with PTRACE_CONT.
714 *
715 * The actual trap might not be PTRACE_EVENT_STOP trap but
716 * the pending condition is cleared regardless.
717 */
718 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
719 break;
720
721 /*
722 * INTERRUPT doesn't disturb existing trap sans one
723 * exception. If ptracer issued LISTEN for the current
724 * STOP, this INTERRUPT should clear LISTEN and re-trap
725 * tracee into STOP.
726 */
727 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
728 signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
729
730 unlock_task_sighand(child, &flags);
731 ret = 0;
732 break;
733
734 case PTRACE_LISTEN:
735 /*
736 * Listen for events. Tracee must be in STOP. It's not
737 * resumed per-se but is not considered to be in TRACED by
738 * wait(2) or ptrace(2). If an async event (e.g. group
739 * stop state change) happens, tracee will enter STOP trap
740 * again. Alternatively, ptracer can issue INTERRUPT to
741 * finish listening and re-trap tracee into STOP.
742 */
743 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
744 break;
745
746 si = child->last_siginfo;
747 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
748 child->jobctl |= JOBCTL_LISTENING;
749 /*
750 * If NOTIFY is set, it means event happened between
751 * start of this trap and now. Trigger re-trap.
752 */
753 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
754 signal_wake_up(child, true);
755 ret = 0;
756 }
757 unlock_task_sighand(child, &flags);
758 break;
759
760 case PTRACE_DETACH: /* detach a process that was attached. */
761 ret = ptrace_detach(child, data);
762 break;
763
764#ifdef CONFIG_BINFMT_ELF_FDPIC
765 case PTRACE_GETFDPIC: {
766 struct mm_struct *mm = get_task_mm(child);
767 unsigned long tmp = 0;
768
769 ret = -ESRCH;
770 if (!mm)
771 break;
772
773 switch (addr) {
774 case PTRACE_GETFDPIC_EXEC:
775 tmp = mm->context.exec_fdpic_loadmap;
776 break;
777 case PTRACE_GETFDPIC_INTERP:
778 tmp = mm->context.interp_fdpic_loadmap;
779 break;
780 default:
781 break;
782 }
783 mmput(mm);
784
785 ret = put_user(tmp, datalp);
786 break;
787 }
788#endif
789
790#ifdef PTRACE_SINGLESTEP
791 case PTRACE_SINGLESTEP:
792#endif
793#ifdef PTRACE_SINGLEBLOCK
794 case PTRACE_SINGLEBLOCK:
795#endif
796#ifdef PTRACE_SYSEMU
797 case PTRACE_SYSEMU:
798 case PTRACE_SYSEMU_SINGLESTEP:
799#endif
800 case PTRACE_SYSCALL:
801 case PTRACE_CONT:
802 return ptrace_resume(child, request, data);
803
804 case PTRACE_KILL:
805 if (child->exit_state) /* already dead */
806 return 0;
807 return ptrace_resume(child, request, SIGKILL);
808
809#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
810 case PTRACE_GETREGSET:
811 case PTRACE_SETREGSET:
812 {
813 struct iovec kiov;
814 struct iovec __user *uiov = datavp;
815
816 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
817 return -EFAULT;
818
819 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
820 __get_user(kiov.iov_len, &uiov->iov_len))
821 return -EFAULT;
822
823 ret = ptrace_regset(child, request, addr, &kiov);
824 if (!ret)
825 ret = __put_user(kiov.iov_len, &uiov->iov_len);
826 break;
827 }
828#endif
829 default:
830 break;
831 }
832
833 return ret;
834}
835
836static struct task_struct *ptrace_get_task_struct(pid_t pid)
837{
838 struct task_struct *child;
839
840 rcu_read_lock();
841 child = find_task_by_vpid(pid);
842 if (child)
843 get_task_struct(child);
844 rcu_read_unlock();
845
846 if (!child)
847 return ERR_PTR(-ESRCH);
848 return child;
849}
850
851#ifndef arch_ptrace_attach
852#define arch_ptrace_attach(child) do { } while (0)
853#endif
854
855SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
856 unsigned long, data)
857{
858 struct task_struct *child;
859 long ret;
860
861 if (request == PTRACE_TRACEME) {
862 ret = ptrace_traceme();
863 if (!ret)
864 arch_ptrace_attach(current);
865 goto out;
866 }
867
868 child = ptrace_get_task_struct(pid);
869 if (IS_ERR(child)) {
870 ret = PTR_ERR(child);
871 goto out;
872 }
873
874 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
875 ret = ptrace_attach(child, request, data);
876 /*
877 * Some architectures need to do book-keeping after
878 * a ptrace attach.
879 */
880 if (!ret)
881 arch_ptrace_attach(child);
882 goto out_put_task_struct;
883 }
884
885 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
886 request == PTRACE_INTERRUPT);
887 if (ret < 0)
888 goto out_put_task_struct;
889
890 ret = arch_ptrace(child, request, addr, data);
891
892 out_put_task_struct:
893 put_task_struct(child);
894 out:
895 return ret;
896}
897
898int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
899 unsigned long data)
900{
901 unsigned long tmp;
902 int copied;
903
904 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
905 if (copied != sizeof(tmp))
906 return -EIO;
907 return put_user(tmp, (unsigned long __user *)data);
908}
909
910int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
911 unsigned long data)
912{
913 int copied;
914
915 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
916 return (copied == sizeof(data)) ? 0 : -EIO;
917}
918
919#if defined CONFIG_COMPAT
920#include <linux/compat.h>
921
922int compat_ptrace_request(struct task_struct *child, compat_long_t request,
923 compat_ulong_t addr, compat_ulong_t data)
924{
925 compat_ulong_t __user *datap = compat_ptr(data);
926 compat_ulong_t word;
927 siginfo_t siginfo;
928 int ret;
929
930 switch (request) {
931 case PTRACE_PEEKTEXT:
932 case PTRACE_PEEKDATA:
933 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
934 if (ret != sizeof(word))
935 ret = -EIO;
936 else
937 ret = put_user(word, datap);
938 break;
939
940 case PTRACE_POKETEXT:
941 case PTRACE_POKEDATA:
942 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
943 ret = (ret != sizeof(data) ? -EIO : 0);
944 break;
945
946 case PTRACE_GETEVENTMSG:
947 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
948 break;
949
950 case PTRACE_GETSIGINFO:
951 ret = ptrace_getsiginfo(child, &siginfo);
952 if (!ret)
953 ret = copy_siginfo_to_user32(
954 (struct compat_siginfo __user *) datap,
955 &siginfo);
956 break;
957
958 case PTRACE_SETSIGINFO:
959 memset(&siginfo, 0, sizeof siginfo);
960 if (copy_siginfo_from_user32(
961 &siginfo, (struct compat_siginfo __user *) datap))
962 ret = -EFAULT;
963 else
964 ret = ptrace_setsiginfo(child, &siginfo);
965 break;
966#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
967 case PTRACE_GETREGSET:
968 case PTRACE_SETREGSET:
969 {
970 struct iovec kiov;
971 struct compat_iovec __user *uiov =
972 (struct compat_iovec __user *) datap;
973 compat_uptr_t ptr;
974 compat_size_t len;
975
976 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
977 return -EFAULT;
978
979 if (__get_user(ptr, &uiov->iov_base) ||
980 __get_user(len, &uiov->iov_len))
981 return -EFAULT;
982
983 kiov.iov_base = compat_ptr(ptr);
984 kiov.iov_len = len;
985
986 ret = ptrace_regset(child, request, addr, &kiov);
987 if (!ret)
988 ret = __put_user(kiov.iov_len, &uiov->iov_len);
989 break;
990 }
991#endif
992
993 default:
994 ret = ptrace_request(child, request, addr, data);
995 }
996
997 return ret;
998}
999
1000asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
1001 compat_long_t addr, compat_long_t data)
1002{
1003 struct task_struct *child;
1004 long ret;
1005
1006 if (request == PTRACE_TRACEME) {
1007 ret = ptrace_traceme();
1008 goto out;
1009 }
1010
1011 child = ptrace_get_task_struct(pid);
1012 if (IS_ERR(child)) {
1013 ret = PTR_ERR(child);
1014 goto out;
1015 }
1016
1017 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1018 ret = ptrace_attach(child, request, data);
1019 /*
1020 * Some architectures need to do book-keeping after
1021 * a ptrace attach.
1022 */
1023 if (!ret)
1024 arch_ptrace_attach(child);
1025 goto out_put_task_struct;
1026 }
1027
1028 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1029 request == PTRACE_INTERRUPT);
1030 if (!ret)
1031 ret = compat_arch_ptrace(child, request, addr, data);
1032
1033 out_put_task_struct:
1034 put_task_struct(child);
1035 out:
1036 return ret;
1037}
1038#endif /* CONFIG_COMPAT */
1039
1040#ifdef CONFIG_HAVE_HW_BREAKPOINT
1041int ptrace_get_breakpoints(struct task_struct *tsk)
1042{
1043 if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
1044 return 0;
1045
1046 return -1;
1047}
1048
1049void ptrace_put_breakpoints(struct task_struct *tsk)
1050{
1051 if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
1052 flush_ptrace_hw_breakpoint(tsk);
1053}
1054#endif /* CONFIG_HAVE_HW_BREAKPOINT */