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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/ptrace.c
4 *
5 * (C) Copyright 1999 Linus Torvalds
6 *
7 * Common interfaces for "ptrace()" which we do not want
8 * to continually duplicate across every architecture.
9 */
10
11#include <linux/capability.h>
12#include <linux/export.h>
13#include <linux/sched.h>
14#include <linux/sched/mm.h>
15#include <linux/sched/coredump.h>
16#include <linux/sched/task.h>
17#include <linux/errno.h>
18#include <linux/mm.h>
19#include <linux/highmem.h>
20#include <linux/pagemap.h>
21#include <linux/ptrace.h>
22#include <linux/security.h>
23#include <linux/signal.h>
24#include <linux/uio.h>
25#include <linux/audit.h>
26#include <linux/pid_namespace.h>
27#include <linux/syscalls.h>
28#include <linux/uaccess.h>
29#include <linux/regset.h>
30#include <linux/hw_breakpoint.h>
31#include <linux/cn_proc.h>
32#include <linux/compat.h>
33#include <linux/sched/signal.h>
34
35#include <asm/syscall.h> /* for syscall_get_* */
36
37/*
38 * Access another process' address space via ptrace.
39 * Source/target buffer must be kernel space,
40 * Do not walk the page table directly, use get_user_pages
41 */
42int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
43 void *buf, int len, unsigned int gup_flags)
44{
45 struct mm_struct *mm;
46 int ret;
47
48 mm = get_task_mm(tsk);
49 if (!mm)
50 return 0;
51
52 if (!tsk->ptrace ||
53 (current != tsk->parent) ||
54 ((get_dumpable(mm) != SUID_DUMP_USER) &&
55 !ptracer_capable(tsk, mm->user_ns))) {
56 mmput(mm);
57 return 0;
58 }
59
60 ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
61 mmput(mm);
62
63 return ret;
64}
65
66
67void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
68 const struct cred *ptracer_cred)
69{
70 BUG_ON(!list_empty(&child->ptrace_entry));
71 list_add(&child->ptrace_entry, &new_parent->ptraced);
72 child->parent = new_parent;
73 child->ptracer_cred = get_cred(ptracer_cred);
74}
75
76/*
77 * ptrace a task: make the debugger its new parent and
78 * move it to the ptrace list.
79 *
80 * Must be called with the tasklist lock write-held.
81 */
82static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
83{
84 __ptrace_link(child, new_parent, current_cred());
85}
86
87/**
88 * __ptrace_unlink - unlink ptracee and restore its execution state
89 * @child: ptracee to be unlinked
90 *
91 * Remove @child from the ptrace list, move it back to the original parent,
92 * and restore the execution state so that it conforms to the group stop
93 * state.
94 *
95 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
96 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
97 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
98 * If the ptracer is exiting, the ptracee can be in any state.
99 *
100 * After detach, the ptracee should be in a state which conforms to the
101 * group stop. If the group is stopped or in the process of stopping, the
102 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
103 * up from TASK_TRACED.
104 *
105 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
106 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
107 * to but in the opposite direction of what happens while attaching to a
108 * stopped task. However, in this direction, the intermediate RUNNING
109 * state is not hidden even from the current ptracer and if it immediately
110 * re-attaches and performs a WNOHANG wait(2), it may fail.
111 *
112 * CONTEXT:
113 * write_lock_irq(tasklist_lock)
114 */
115void __ptrace_unlink(struct task_struct *child)
116{
117 const struct cred *old_cred;
118 BUG_ON(!child->ptrace);
119
120 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
121#ifdef TIF_SYSCALL_EMU
122 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
123#endif
124
125 child->parent = child->real_parent;
126 list_del_init(&child->ptrace_entry);
127 old_cred = child->ptracer_cred;
128 child->ptracer_cred = NULL;
129 put_cred(old_cred);
130
131 spin_lock(&child->sighand->siglock);
132 child->ptrace = 0;
133 /*
134 * Clear all pending traps and TRAPPING. TRAPPING should be
135 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
136 */
137 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
138 task_clear_jobctl_trapping(child);
139
140 /*
141 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
142 * @child isn't dead.
143 */
144 if (!(child->flags & PF_EXITING) &&
145 (child->signal->flags & SIGNAL_STOP_STOPPED ||
146 child->signal->group_stop_count)) {
147 child->jobctl |= JOBCTL_STOP_PENDING;
148
149 /*
150 * This is only possible if this thread was cloned by the
151 * traced task running in the stopped group, set the signal
152 * for the future reports.
153 * FIXME: we should change ptrace_init_task() to handle this
154 * case.
155 */
156 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
157 child->jobctl |= SIGSTOP;
158 }
159
160 /*
161 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
162 * @child in the butt. Note that @resume should be used iff @child
163 * is in TASK_TRACED; otherwise, we might unduly disrupt
164 * TASK_KILLABLE sleeps.
165 */
166 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
167 ptrace_signal_wake_up(child, true);
168
169 spin_unlock(&child->sighand->siglock);
170}
171
172/* Ensure that nothing can wake it up, even SIGKILL */
173static bool ptrace_freeze_traced(struct task_struct *task)
174{
175 bool ret = false;
176
177 /* Lockless, nobody but us can set this flag */
178 if (task->jobctl & JOBCTL_LISTENING)
179 return ret;
180
181 spin_lock_irq(&task->sighand->siglock);
182 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
183 task->state = __TASK_TRACED;
184 ret = true;
185 }
186 spin_unlock_irq(&task->sighand->siglock);
187
188 return ret;
189}
190
191static void ptrace_unfreeze_traced(struct task_struct *task)
192{
193 if (task->state != __TASK_TRACED)
194 return;
195
196 WARN_ON(!task->ptrace || task->parent != current);
197
198 /*
199 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
200 * Recheck state under the lock to close this race.
201 */
202 spin_lock_irq(&task->sighand->siglock);
203 if (task->state == __TASK_TRACED) {
204 if (__fatal_signal_pending(task))
205 wake_up_state(task, __TASK_TRACED);
206 else
207 task->state = TASK_TRACED;
208 }
209 spin_unlock_irq(&task->sighand->siglock);
210}
211
212/**
213 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
214 * @child: ptracee to check for
215 * @ignore_state: don't check whether @child is currently %TASK_TRACED
216 *
217 * Check whether @child is being ptraced by %current and ready for further
218 * ptrace operations. If @ignore_state is %false, @child also should be in
219 * %TASK_TRACED state and on return the child is guaranteed to be traced
220 * and not executing. If @ignore_state is %true, @child can be in any
221 * state.
222 *
223 * CONTEXT:
224 * Grabs and releases tasklist_lock and @child->sighand->siglock.
225 *
226 * RETURNS:
227 * 0 on success, -ESRCH if %child is not ready.
228 */
229static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
230{
231 int ret = -ESRCH;
232
233 /*
234 * We take the read lock around doing both checks to close a
235 * possible race where someone else was tracing our child and
236 * detached between these two checks. After this locked check,
237 * we are sure that this is our traced child and that can only
238 * be changed by us so it's not changing right after this.
239 */
240 read_lock(&tasklist_lock);
241 if (child->ptrace && child->parent == current) {
242 WARN_ON(child->state == __TASK_TRACED);
243 /*
244 * child->sighand can't be NULL, release_task()
245 * does ptrace_unlink() before __exit_signal().
246 */
247 if (ignore_state || ptrace_freeze_traced(child))
248 ret = 0;
249 }
250 read_unlock(&tasklist_lock);
251
252 if (!ret && !ignore_state) {
253 if (!wait_task_inactive(child, __TASK_TRACED)) {
254 /*
255 * This can only happen if may_ptrace_stop() fails and
256 * ptrace_stop() changes ->state back to TASK_RUNNING,
257 * so we should not worry about leaking __TASK_TRACED.
258 */
259 WARN_ON(child->state == __TASK_TRACED);
260 ret = -ESRCH;
261 }
262 }
263
264 return ret;
265}
266
267static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
268{
269 if (mode & PTRACE_MODE_NOAUDIT)
270 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
271 else
272 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
273}
274
275/* Returns 0 on success, -errno on denial. */
276static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
277{
278 const struct cred *cred = current_cred(), *tcred;
279 struct mm_struct *mm;
280 kuid_t caller_uid;
281 kgid_t caller_gid;
282
283 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
284 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
285 return -EPERM;
286 }
287
288 /* May we inspect the given task?
289 * This check is used both for attaching with ptrace
290 * and for allowing access to sensitive information in /proc.
291 *
292 * ptrace_attach denies several cases that /proc allows
293 * because setting up the necessary parent/child relationship
294 * or halting the specified task is impossible.
295 */
296
297 /* Don't let security modules deny introspection */
298 if (same_thread_group(task, current))
299 return 0;
300 rcu_read_lock();
301 if (mode & PTRACE_MODE_FSCREDS) {
302 caller_uid = cred->fsuid;
303 caller_gid = cred->fsgid;
304 } else {
305 /*
306 * Using the euid would make more sense here, but something
307 * in userland might rely on the old behavior, and this
308 * shouldn't be a security problem since
309 * PTRACE_MODE_REALCREDS implies that the caller explicitly
310 * used a syscall that requests access to another process
311 * (and not a filesystem syscall to procfs).
312 */
313 caller_uid = cred->uid;
314 caller_gid = cred->gid;
315 }
316 tcred = __task_cred(task);
317 if (uid_eq(caller_uid, tcred->euid) &&
318 uid_eq(caller_uid, tcred->suid) &&
319 uid_eq(caller_uid, tcred->uid) &&
320 gid_eq(caller_gid, tcred->egid) &&
321 gid_eq(caller_gid, tcred->sgid) &&
322 gid_eq(caller_gid, tcred->gid))
323 goto ok;
324 if (ptrace_has_cap(tcred->user_ns, mode))
325 goto ok;
326 rcu_read_unlock();
327 return -EPERM;
328ok:
329 rcu_read_unlock();
330 /*
331 * If a task drops privileges and becomes nondumpable (through a syscall
332 * like setresuid()) while we are trying to access it, we must ensure
333 * that the dumpability is read after the credentials; otherwise,
334 * we may be able to attach to a task that we shouldn't be able to
335 * attach to (as if the task had dropped privileges without becoming
336 * nondumpable).
337 * Pairs with a write barrier in commit_creds().
338 */
339 smp_rmb();
340 mm = task->mm;
341 if (mm &&
342 ((get_dumpable(mm) != SUID_DUMP_USER) &&
343 !ptrace_has_cap(mm->user_ns, mode)))
344 return -EPERM;
345
346 return security_ptrace_access_check(task, mode);
347}
348
349bool ptrace_may_access(struct task_struct *task, unsigned int mode)
350{
351 int err;
352 task_lock(task);
353 err = __ptrace_may_access(task, mode);
354 task_unlock(task);
355 return !err;
356}
357
358static int ptrace_attach(struct task_struct *task, long request,
359 unsigned long addr,
360 unsigned long flags)
361{
362 bool seize = (request == PTRACE_SEIZE);
363 int retval;
364
365 retval = -EIO;
366 if (seize) {
367 if (addr != 0)
368 goto out;
369 if (flags & ~(unsigned long)PTRACE_O_MASK)
370 goto out;
371 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
372 } else {
373 flags = PT_PTRACED;
374 }
375
376 audit_ptrace(task);
377
378 retval = -EPERM;
379 if (unlikely(task->flags & PF_KTHREAD))
380 goto out;
381 if (same_thread_group(task, current))
382 goto out;
383
384 /*
385 * Protect exec's credential calculations against our interference;
386 * SUID, SGID and LSM creds get determined differently
387 * under ptrace.
388 */
389 retval = -ERESTARTNOINTR;
390 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
391 goto out;
392
393 task_lock(task);
394 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
395 task_unlock(task);
396 if (retval)
397 goto unlock_creds;
398
399 write_lock_irq(&tasklist_lock);
400 retval = -EPERM;
401 if (unlikely(task->exit_state))
402 goto unlock_tasklist;
403 if (task->ptrace)
404 goto unlock_tasklist;
405
406 if (seize)
407 flags |= PT_SEIZED;
408 task->ptrace = flags;
409
410 ptrace_link(task, current);
411
412 /* SEIZE doesn't trap tracee on attach */
413 if (!seize)
414 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
415
416 spin_lock(&task->sighand->siglock);
417
418 /*
419 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
420 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
421 * will be cleared if the child completes the transition or any
422 * event which clears the group stop states happens. We'll wait
423 * for the transition to complete before returning from this
424 * function.
425 *
426 * This hides STOPPED -> RUNNING -> TRACED transition from the
427 * attaching thread but a different thread in the same group can
428 * still observe the transient RUNNING state. IOW, if another
429 * thread's WNOHANG wait(2) on the stopped tracee races against
430 * ATTACH, the wait(2) may fail due to the transient RUNNING.
431 *
432 * The following task_is_stopped() test is safe as both transitions
433 * in and out of STOPPED are protected by siglock.
434 */
435 if (task_is_stopped(task) &&
436 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
437 signal_wake_up_state(task, __TASK_STOPPED);
438
439 spin_unlock(&task->sighand->siglock);
440
441 retval = 0;
442unlock_tasklist:
443 write_unlock_irq(&tasklist_lock);
444unlock_creds:
445 mutex_unlock(&task->signal->cred_guard_mutex);
446out:
447 if (!retval) {
448 /*
449 * We do not bother to change retval or clear JOBCTL_TRAPPING
450 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
451 * not return to user-mode, it will exit and clear this bit in
452 * __ptrace_unlink() if it wasn't already cleared by the tracee;
453 * and until then nobody can ptrace this task.
454 */
455 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
456 proc_ptrace_connector(task, PTRACE_ATTACH);
457 }
458
459 return retval;
460}
461
462/**
463 * ptrace_traceme -- helper for PTRACE_TRACEME
464 *
465 * Performs checks and sets PT_PTRACED.
466 * Should be used by all ptrace implementations for PTRACE_TRACEME.
467 */
468static int ptrace_traceme(void)
469{
470 int ret = -EPERM;
471
472 write_lock_irq(&tasklist_lock);
473 /* Are we already being traced? */
474 if (!current->ptrace) {
475 ret = security_ptrace_traceme(current->parent);
476 /*
477 * Check PF_EXITING to ensure ->real_parent has not passed
478 * exit_ptrace(). Otherwise we don't report the error but
479 * pretend ->real_parent untraces us right after return.
480 */
481 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
482 current->ptrace = PT_PTRACED;
483 ptrace_link(current, current->real_parent);
484 }
485 }
486 write_unlock_irq(&tasklist_lock);
487
488 return ret;
489}
490
491/*
492 * Called with irqs disabled, returns true if childs should reap themselves.
493 */
494static int ignoring_children(struct sighand_struct *sigh)
495{
496 int ret;
497 spin_lock(&sigh->siglock);
498 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
499 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
500 spin_unlock(&sigh->siglock);
501 return ret;
502}
503
504/*
505 * Called with tasklist_lock held for writing.
506 * Unlink a traced task, and clean it up if it was a traced zombie.
507 * Return true if it needs to be reaped with release_task().
508 * (We can't call release_task() here because we already hold tasklist_lock.)
509 *
510 * If it's a zombie, our attachedness prevented normal parent notification
511 * or self-reaping. Do notification now if it would have happened earlier.
512 * If it should reap itself, return true.
513 *
514 * If it's our own child, there is no notification to do. But if our normal
515 * children self-reap, then this child was prevented by ptrace and we must
516 * reap it now, in that case we must also wake up sub-threads sleeping in
517 * do_wait().
518 */
519static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
520{
521 bool dead;
522
523 __ptrace_unlink(p);
524
525 if (p->exit_state != EXIT_ZOMBIE)
526 return false;
527
528 dead = !thread_group_leader(p);
529
530 if (!dead && thread_group_empty(p)) {
531 if (!same_thread_group(p->real_parent, tracer))
532 dead = do_notify_parent(p, p->exit_signal);
533 else if (ignoring_children(tracer->sighand)) {
534 __wake_up_parent(p, tracer);
535 dead = true;
536 }
537 }
538 /* Mark it as in the process of being reaped. */
539 if (dead)
540 p->exit_state = EXIT_DEAD;
541 return dead;
542}
543
544static int ptrace_detach(struct task_struct *child, unsigned int data)
545{
546 if (!valid_signal(data))
547 return -EIO;
548
549 /* Architecture-specific hardware disable .. */
550 ptrace_disable(child);
551
552 write_lock_irq(&tasklist_lock);
553 /*
554 * We rely on ptrace_freeze_traced(). It can't be killed and
555 * untraced by another thread, it can't be a zombie.
556 */
557 WARN_ON(!child->ptrace || child->exit_state);
558 /*
559 * tasklist_lock avoids the race with wait_task_stopped(), see
560 * the comment in ptrace_resume().
561 */
562 child->exit_code = data;
563 __ptrace_detach(current, child);
564 write_unlock_irq(&tasklist_lock);
565
566 proc_ptrace_connector(child, PTRACE_DETACH);
567
568 return 0;
569}
570
571/*
572 * Detach all tasks we were using ptrace on. Called with tasklist held
573 * for writing.
574 */
575void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
576{
577 struct task_struct *p, *n;
578
579 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
580 if (unlikely(p->ptrace & PT_EXITKILL))
581 send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
582
583 if (__ptrace_detach(tracer, p))
584 list_add(&p->ptrace_entry, dead);
585 }
586}
587
588int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
589{
590 int copied = 0;
591
592 while (len > 0) {
593 char buf[128];
594 int this_len, retval;
595
596 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
597 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
598
599 if (!retval) {
600 if (copied)
601 break;
602 return -EIO;
603 }
604 if (copy_to_user(dst, buf, retval))
605 return -EFAULT;
606 copied += retval;
607 src += retval;
608 dst += retval;
609 len -= retval;
610 }
611 return copied;
612}
613
614int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
615{
616 int copied = 0;
617
618 while (len > 0) {
619 char buf[128];
620 int this_len, retval;
621
622 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
623 if (copy_from_user(buf, src, this_len))
624 return -EFAULT;
625 retval = ptrace_access_vm(tsk, dst, buf, this_len,
626 FOLL_FORCE | FOLL_WRITE);
627 if (!retval) {
628 if (copied)
629 break;
630 return -EIO;
631 }
632 copied += retval;
633 src += retval;
634 dst += retval;
635 len -= retval;
636 }
637 return copied;
638}
639
640static int ptrace_setoptions(struct task_struct *child, unsigned long data)
641{
642 unsigned flags;
643
644 if (data & ~(unsigned long)PTRACE_O_MASK)
645 return -EINVAL;
646
647 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
648 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
649 !IS_ENABLED(CONFIG_SECCOMP))
650 return -EINVAL;
651
652 if (!capable(CAP_SYS_ADMIN))
653 return -EPERM;
654
655 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
656 current->ptrace & PT_SUSPEND_SECCOMP)
657 return -EPERM;
658 }
659
660 /* Avoid intermediate state when all opts are cleared */
661 flags = child->ptrace;
662 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
663 flags |= (data << PT_OPT_FLAG_SHIFT);
664 child->ptrace = flags;
665
666 return 0;
667}
668
669static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
670{
671 unsigned long flags;
672 int error = -ESRCH;
673
674 if (lock_task_sighand(child, &flags)) {
675 error = -EINVAL;
676 if (likely(child->last_siginfo != NULL)) {
677 copy_siginfo(info, child->last_siginfo);
678 error = 0;
679 }
680 unlock_task_sighand(child, &flags);
681 }
682 return error;
683}
684
685static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
686{
687 unsigned long flags;
688 int error = -ESRCH;
689
690 if (lock_task_sighand(child, &flags)) {
691 error = -EINVAL;
692 if (likely(child->last_siginfo != NULL)) {
693 copy_siginfo(child->last_siginfo, info);
694 error = 0;
695 }
696 unlock_task_sighand(child, &flags);
697 }
698 return error;
699}
700
701static int ptrace_peek_siginfo(struct task_struct *child,
702 unsigned long addr,
703 unsigned long data)
704{
705 struct ptrace_peeksiginfo_args arg;
706 struct sigpending *pending;
707 struct sigqueue *q;
708 int ret, i;
709
710 ret = copy_from_user(&arg, (void __user *) addr,
711 sizeof(struct ptrace_peeksiginfo_args));
712 if (ret)
713 return -EFAULT;
714
715 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
716 return -EINVAL; /* unknown flags */
717
718 if (arg.nr < 0)
719 return -EINVAL;
720
721 /* Ensure arg.off fits in an unsigned long */
722 if (arg.off > ULONG_MAX)
723 return 0;
724
725 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
726 pending = &child->signal->shared_pending;
727 else
728 pending = &child->pending;
729
730 for (i = 0; i < arg.nr; ) {
731 kernel_siginfo_t info;
732 unsigned long off = arg.off + i;
733 bool found = false;
734
735 spin_lock_irq(&child->sighand->siglock);
736 list_for_each_entry(q, &pending->list, list) {
737 if (!off--) {
738 found = true;
739 copy_siginfo(&info, &q->info);
740 break;
741 }
742 }
743 spin_unlock_irq(&child->sighand->siglock);
744
745 if (!found) /* beyond the end of the list */
746 break;
747
748#ifdef CONFIG_COMPAT
749 if (unlikely(in_compat_syscall())) {
750 compat_siginfo_t __user *uinfo = compat_ptr(data);
751
752 if (copy_siginfo_to_user32(uinfo, &info)) {
753 ret = -EFAULT;
754 break;
755 }
756
757 } else
758#endif
759 {
760 siginfo_t __user *uinfo = (siginfo_t __user *) data;
761
762 if (copy_siginfo_to_user(uinfo, &info)) {
763 ret = -EFAULT;
764 break;
765 }
766 }
767
768 data += sizeof(siginfo_t);
769 i++;
770
771 if (signal_pending(current))
772 break;
773
774 cond_resched();
775 }
776
777 if (i > 0)
778 return i;
779
780 return ret;
781}
782
783#ifdef PTRACE_SINGLESTEP
784#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
785#else
786#define is_singlestep(request) 0
787#endif
788
789#ifdef PTRACE_SINGLEBLOCK
790#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
791#else
792#define is_singleblock(request) 0
793#endif
794
795#ifdef PTRACE_SYSEMU
796#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
797#else
798#define is_sysemu_singlestep(request) 0
799#endif
800
801static int ptrace_resume(struct task_struct *child, long request,
802 unsigned long data)
803{
804 bool need_siglock;
805
806 if (!valid_signal(data))
807 return -EIO;
808
809 if (request == PTRACE_SYSCALL)
810 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
811 else
812 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
813
814#ifdef TIF_SYSCALL_EMU
815 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
816 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
817 else
818 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
819#endif
820
821 if (is_singleblock(request)) {
822 if (unlikely(!arch_has_block_step()))
823 return -EIO;
824 user_enable_block_step(child);
825 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
826 if (unlikely(!arch_has_single_step()))
827 return -EIO;
828 user_enable_single_step(child);
829 } else {
830 user_disable_single_step(child);
831 }
832
833 /*
834 * Change ->exit_code and ->state under siglock to avoid the race
835 * with wait_task_stopped() in between; a non-zero ->exit_code will
836 * wrongly look like another report from tracee.
837 *
838 * Note that we need siglock even if ->exit_code == data and/or this
839 * status was not reported yet, the new status must not be cleared by
840 * wait_task_stopped() after resume.
841 *
842 * If data == 0 we do not care if wait_task_stopped() reports the old
843 * status and clears the code too; this can't race with the tracee, it
844 * takes siglock after resume.
845 */
846 need_siglock = data && !thread_group_empty(current);
847 if (need_siglock)
848 spin_lock_irq(&child->sighand->siglock);
849 child->exit_code = data;
850 wake_up_state(child, __TASK_TRACED);
851 if (need_siglock)
852 spin_unlock_irq(&child->sighand->siglock);
853
854 return 0;
855}
856
857#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
858
859static const struct user_regset *
860find_regset(const struct user_regset_view *view, unsigned int type)
861{
862 const struct user_regset *regset;
863 int n;
864
865 for (n = 0; n < view->n; ++n) {
866 regset = view->regsets + n;
867 if (regset->core_note_type == type)
868 return regset;
869 }
870
871 return NULL;
872}
873
874static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
875 struct iovec *kiov)
876{
877 const struct user_regset_view *view = task_user_regset_view(task);
878 const struct user_regset *regset = find_regset(view, type);
879 int regset_no;
880
881 if (!regset || (kiov->iov_len % regset->size) != 0)
882 return -EINVAL;
883
884 regset_no = regset - view->regsets;
885 kiov->iov_len = min(kiov->iov_len,
886 (__kernel_size_t) (regset->n * regset->size));
887
888 if (req == PTRACE_GETREGSET)
889 return copy_regset_to_user(task, view, regset_no, 0,
890 kiov->iov_len, kiov->iov_base);
891 else
892 return copy_regset_from_user(task, view, regset_no, 0,
893 kiov->iov_len, kiov->iov_base);
894}
895
896/*
897 * This is declared in linux/regset.h and defined in machine-dependent
898 * code. We put the export here, near the primary machine-neutral use,
899 * to ensure no machine forgets it.
900 */
901EXPORT_SYMBOL_GPL(task_user_regset_view);
902
903static unsigned long
904ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
905 struct ptrace_syscall_info *info)
906{
907 unsigned long args[ARRAY_SIZE(info->entry.args)];
908 int i;
909
910 info->op = PTRACE_SYSCALL_INFO_ENTRY;
911 info->entry.nr = syscall_get_nr(child, regs);
912 syscall_get_arguments(child, regs, args);
913 for (i = 0; i < ARRAY_SIZE(args); i++)
914 info->entry.args[i] = args[i];
915
916 /* args is the last field in struct ptrace_syscall_info.entry */
917 return offsetofend(struct ptrace_syscall_info, entry.args);
918}
919
920static unsigned long
921ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
922 struct ptrace_syscall_info *info)
923{
924 /*
925 * As struct ptrace_syscall_info.entry is currently a subset
926 * of struct ptrace_syscall_info.seccomp, it makes sense to
927 * initialize that subset using ptrace_get_syscall_info_entry().
928 * This can be reconsidered in the future if these structures
929 * diverge significantly enough.
930 */
931 ptrace_get_syscall_info_entry(child, regs, info);
932 info->op = PTRACE_SYSCALL_INFO_SECCOMP;
933 info->seccomp.ret_data = child->ptrace_message;
934
935 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
936 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
937}
938
939static unsigned long
940ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
941 struct ptrace_syscall_info *info)
942{
943 info->op = PTRACE_SYSCALL_INFO_EXIT;
944 info->exit.rval = syscall_get_error(child, regs);
945 info->exit.is_error = !!info->exit.rval;
946 if (!info->exit.is_error)
947 info->exit.rval = syscall_get_return_value(child, regs);
948
949 /* is_error is the last field in struct ptrace_syscall_info.exit */
950 return offsetofend(struct ptrace_syscall_info, exit.is_error);
951}
952
953static int
954ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
955 void __user *datavp)
956{
957 struct pt_regs *regs = task_pt_regs(child);
958 struct ptrace_syscall_info info = {
959 .op = PTRACE_SYSCALL_INFO_NONE,
960 .arch = syscall_get_arch(child),
961 .instruction_pointer = instruction_pointer(regs),
962 .stack_pointer = user_stack_pointer(regs),
963 };
964 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
965 unsigned long write_size;
966
967 /*
968 * This does not need lock_task_sighand() to access
969 * child->last_siginfo because ptrace_freeze_traced()
970 * called earlier by ptrace_check_attach() ensures that
971 * the tracee cannot go away and clear its last_siginfo.
972 */
973 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
974 case SIGTRAP | 0x80:
975 switch (child->ptrace_message) {
976 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
977 actual_size = ptrace_get_syscall_info_entry(child, regs,
978 &info);
979 break;
980 case PTRACE_EVENTMSG_SYSCALL_EXIT:
981 actual_size = ptrace_get_syscall_info_exit(child, regs,
982 &info);
983 break;
984 }
985 break;
986 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
987 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
988 &info);
989 break;
990 }
991
992 write_size = min(actual_size, user_size);
993 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
994}
995#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
996
997int ptrace_request(struct task_struct *child, long request,
998 unsigned long addr, unsigned long data)
999{
1000 bool seized = child->ptrace & PT_SEIZED;
1001 int ret = -EIO;
1002 kernel_siginfo_t siginfo, *si;
1003 void __user *datavp = (void __user *) data;
1004 unsigned long __user *datalp = datavp;
1005 unsigned long flags;
1006
1007 switch (request) {
1008 case PTRACE_PEEKTEXT:
1009 case PTRACE_PEEKDATA:
1010 return generic_ptrace_peekdata(child, addr, data);
1011 case PTRACE_POKETEXT:
1012 case PTRACE_POKEDATA:
1013 return generic_ptrace_pokedata(child, addr, data);
1014
1015#ifdef PTRACE_OLDSETOPTIONS
1016 case PTRACE_OLDSETOPTIONS:
1017#endif
1018 case PTRACE_SETOPTIONS:
1019 ret = ptrace_setoptions(child, data);
1020 break;
1021 case PTRACE_GETEVENTMSG:
1022 ret = put_user(child->ptrace_message, datalp);
1023 break;
1024
1025 case PTRACE_PEEKSIGINFO:
1026 ret = ptrace_peek_siginfo(child, addr, data);
1027 break;
1028
1029 case PTRACE_GETSIGINFO:
1030 ret = ptrace_getsiginfo(child, &siginfo);
1031 if (!ret)
1032 ret = copy_siginfo_to_user(datavp, &siginfo);
1033 break;
1034
1035 case PTRACE_SETSIGINFO:
1036 ret = copy_siginfo_from_user(&siginfo, datavp);
1037 if (!ret)
1038 ret = ptrace_setsiginfo(child, &siginfo);
1039 break;
1040
1041 case PTRACE_GETSIGMASK: {
1042 sigset_t *mask;
1043
1044 if (addr != sizeof(sigset_t)) {
1045 ret = -EINVAL;
1046 break;
1047 }
1048
1049 if (test_tsk_restore_sigmask(child))
1050 mask = &child->saved_sigmask;
1051 else
1052 mask = &child->blocked;
1053
1054 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
1055 ret = -EFAULT;
1056 else
1057 ret = 0;
1058
1059 break;
1060 }
1061
1062 case PTRACE_SETSIGMASK: {
1063 sigset_t new_set;
1064
1065 if (addr != sizeof(sigset_t)) {
1066 ret = -EINVAL;
1067 break;
1068 }
1069
1070 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1071 ret = -EFAULT;
1072 break;
1073 }
1074
1075 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1076
1077 /*
1078 * Every thread does recalc_sigpending() after resume, so
1079 * retarget_shared_pending() and recalc_sigpending() are not
1080 * called here.
1081 */
1082 spin_lock_irq(&child->sighand->siglock);
1083 child->blocked = new_set;
1084 spin_unlock_irq(&child->sighand->siglock);
1085
1086 clear_tsk_restore_sigmask(child);
1087
1088 ret = 0;
1089 break;
1090 }
1091
1092 case PTRACE_INTERRUPT:
1093 /*
1094 * Stop tracee without any side-effect on signal or job
1095 * control. At least one trap is guaranteed to happen
1096 * after this request. If @child is already trapped, the
1097 * current trap is not disturbed and another trap will
1098 * happen after the current trap is ended with PTRACE_CONT.
1099 *
1100 * The actual trap might not be PTRACE_EVENT_STOP trap but
1101 * the pending condition is cleared regardless.
1102 */
1103 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1104 break;
1105
1106 /*
1107 * INTERRUPT doesn't disturb existing trap sans one
1108 * exception. If ptracer issued LISTEN for the current
1109 * STOP, this INTERRUPT should clear LISTEN and re-trap
1110 * tracee into STOP.
1111 */
1112 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
1113 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
1114
1115 unlock_task_sighand(child, &flags);
1116 ret = 0;
1117 break;
1118
1119 case PTRACE_LISTEN:
1120 /*
1121 * Listen for events. Tracee must be in STOP. It's not
1122 * resumed per-se but is not considered to be in TRACED by
1123 * wait(2) or ptrace(2). If an async event (e.g. group
1124 * stop state change) happens, tracee will enter STOP trap
1125 * again. Alternatively, ptracer can issue INTERRUPT to
1126 * finish listening and re-trap tracee into STOP.
1127 */
1128 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1129 break;
1130
1131 si = child->last_siginfo;
1132 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1133 child->jobctl |= JOBCTL_LISTENING;
1134 /*
1135 * If NOTIFY is set, it means event happened between
1136 * start of this trap and now. Trigger re-trap.
1137 */
1138 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1139 ptrace_signal_wake_up(child, true);
1140 ret = 0;
1141 }
1142 unlock_task_sighand(child, &flags);
1143 break;
1144
1145 case PTRACE_DETACH: /* detach a process that was attached. */
1146 ret = ptrace_detach(child, data);
1147 break;
1148
1149#ifdef CONFIG_BINFMT_ELF_FDPIC
1150 case PTRACE_GETFDPIC: {
1151 struct mm_struct *mm = get_task_mm(child);
1152 unsigned long tmp = 0;
1153
1154 ret = -ESRCH;
1155 if (!mm)
1156 break;
1157
1158 switch (addr) {
1159 case PTRACE_GETFDPIC_EXEC:
1160 tmp = mm->context.exec_fdpic_loadmap;
1161 break;
1162 case PTRACE_GETFDPIC_INTERP:
1163 tmp = mm->context.interp_fdpic_loadmap;
1164 break;
1165 default:
1166 break;
1167 }
1168 mmput(mm);
1169
1170 ret = put_user(tmp, datalp);
1171 break;
1172 }
1173#endif
1174
1175#ifdef PTRACE_SINGLESTEP
1176 case PTRACE_SINGLESTEP:
1177#endif
1178#ifdef PTRACE_SINGLEBLOCK
1179 case PTRACE_SINGLEBLOCK:
1180#endif
1181#ifdef PTRACE_SYSEMU
1182 case PTRACE_SYSEMU:
1183 case PTRACE_SYSEMU_SINGLESTEP:
1184#endif
1185 case PTRACE_SYSCALL:
1186 case PTRACE_CONT:
1187 return ptrace_resume(child, request, data);
1188
1189 case PTRACE_KILL:
1190 if (child->exit_state) /* already dead */
1191 return 0;
1192 return ptrace_resume(child, request, SIGKILL);
1193
1194#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1195 case PTRACE_GETREGSET:
1196 case PTRACE_SETREGSET: {
1197 struct iovec kiov;
1198 struct iovec __user *uiov = datavp;
1199
1200 if (!access_ok(uiov, sizeof(*uiov)))
1201 return -EFAULT;
1202
1203 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1204 __get_user(kiov.iov_len, &uiov->iov_len))
1205 return -EFAULT;
1206
1207 ret = ptrace_regset(child, request, addr, &kiov);
1208 if (!ret)
1209 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1210 break;
1211 }
1212
1213 case PTRACE_GET_SYSCALL_INFO:
1214 ret = ptrace_get_syscall_info(child, addr, datavp);
1215 break;
1216#endif
1217
1218 case PTRACE_SECCOMP_GET_FILTER:
1219 ret = seccomp_get_filter(child, addr, datavp);
1220 break;
1221
1222 case PTRACE_SECCOMP_GET_METADATA:
1223 ret = seccomp_get_metadata(child, addr, datavp);
1224 break;
1225
1226 default:
1227 break;
1228 }
1229
1230 return ret;
1231}
1232
1233#ifndef arch_ptrace_attach
1234#define arch_ptrace_attach(child) do { } while (0)
1235#endif
1236
1237SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1238 unsigned long, data)
1239{
1240 struct task_struct *child;
1241 long ret;
1242
1243 if (request == PTRACE_TRACEME) {
1244 ret = ptrace_traceme();
1245 if (!ret)
1246 arch_ptrace_attach(current);
1247 goto out;
1248 }
1249
1250 child = find_get_task_by_vpid(pid);
1251 if (!child) {
1252 ret = -ESRCH;
1253 goto out;
1254 }
1255
1256 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1257 ret = ptrace_attach(child, request, addr, data);
1258 /*
1259 * Some architectures need to do book-keeping after
1260 * a ptrace attach.
1261 */
1262 if (!ret)
1263 arch_ptrace_attach(child);
1264 goto out_put_task_struct;
1265 }
1266
1267 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1268 request == PTRACE_INTERRUPT);
1269 if (ret < 0)
1270 goto out_put_task_struct;
1271
1272 ret = arch_ptrace(child, request, addr, data);
1273 if (ret || request != PTRACE_DETACH)
1274 ptrace_unfreeze_traced(child);
1275
1276 out_put_task_struct:
1277 put_task_struct(child);
1278 out:
1279 return ret;
1280}
1281
1282int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1283 unsigned long data)
1284{
1285 unsigned long tmp;
1286 int copied;
1287
1288 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1289 if (copied != sizeof(tmp))
1290 return -EIO;
1291 return put_user(tmp, (unsigned long __user *)data);
1292}
1293
1294int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1295 unsigned long data)
1296{
1297 int copied;
1298
1299 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1300 FOLL_FORCE | FOLL_WRITE);
1301 return (copied == sizeof(data)) ? 0 : -EIO;
1302}
1303
1304#if defined CONFIG_COMPAT
1305
1306int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1307 compat_ulong_t addr, compat_ulong_t data)
1308{
1309 compat_ulong_t __user *datap = compat_ptr(data);
1310 compat_ulong_t word;
1311 kernel_siginfo_t siginfo;
1312 int ret;
1313
1314 switch (request) {
1315 case PTRACE_PEEKTEXT:
1316 case PTRACE_PEEKDATA:
1317 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1318 FOLL_FORCE);
1319 if (ret != sizeof(word))
1320 ret = -EIO;
1321 else
1322 ret = put_user(word, datap);
1323 break;
1324
1325 case PTRACE_POKETEXT:
1326 case PTRACE_POKEDATA:
1327 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1328 FOLL_FORCE | FOLL_WRITE);
1329 ret = (ret != sizeof(data) ? -EIO : 0);
1330 break;
1331
1332 case PTRACE_GETEVENTMSG:
1333 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1334 break;
1335
1336 case PTRACE_GETSIGINFO:
1337 ret = ptrace_getsiginfo(child, &siginfo);
1338 if (!ret)
1339 ret = copy_siginfo_to_user32(
1340 (struct compat_siginfo __user *) datap,
1341 &siginfo);
1342 break;
1343
1344 case PTRACE_SETSIGINFO:
1345 ret = copy_siginfo_from_user32(
1346 &siginfo, (struct compat_siginfo __user *) datap);
1347 if (!ret)
1348 ret = ptrace_setsiginfo(child, &siginfo);
1349 break;
1350#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1351 case PTRACE_GETREGSET:
1352 case PTRACE_SETREGSET:
1353 {
1354 struct iovec kiov;
1355 struct compat_iovec __user *uiov =
1356 (struct compat_iovec __user *) datap;
1357 compat_uptr_t ptr;
1358 compat_size_t len;
1359
1360 if (!access_ok(uiov, sizeof(*uiov)))
1361 return -EFAULT;
1362
1363 if (__get_user(ptr, &uiov->iov_base) ||
1364 __get_user(len, &uiov->iov_len))
1365 return -EFAULT;
1366
1367 kiov.iov_base = compat_ptr(ptr);
1368 kiov.iov_len = len;
1369
1370 ret = ptrace_regset(child, request, addr, &kiov);
1371 if (!ret)
1372 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1373 break;
1374 }
1375#endif
1376
1377 default:
1378 ret = ptrace_request(child, request, addr, data);
1379 }
1380
1381 return ret;
1382}
1383
1384COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1385 compat_long_t, addr, compat_long_t, data)
1386{
1387 struct task_struct *child;
1388 long ret;
1389
1390 if (request == PTRACE_TRACEME) {
1391 ret = ptrace_traceme();
1392 goto out;
1393 }
1394
1395 child = find_get_task_by_vpid(pid);
1396 if (!child) {
1397 ret = -ESRCH;
1398 goto out;
1399 }
1400
1401 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1402 ret = ptrace_attach(child, request, addr, data);
1403 /*
1404 * Some architectures need to do book-keeping after
1405 * a ptrace attach.
1406 */
1407 if (!ret)
1408 arch_ptrace_attach(child);
1409 goto out_put_task_struct;
1410 }
1411
1412 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1413 request == PTRACE_INTERRUPT);
1414 if (!ret) {
1415 ret = compat_arch_ptrace(child, request, addr, data);
1416 if (ret || request != PTRACE_DETACH)
1417 ptrace_unfreeze_traced(child);
1418 }
1419
1420 out_put_task_struct:
1421 put_task_struct(child);
1422 out:
1423 return ret;
1424}
1425#endif /* CONFIG_COMPAT */
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/ptrace.c
4 *
5 * (C) Copyright 1999 Linus Torvalds
6 *
7 * Common interfaces for "ptrace()" which we do not want
8 * to continually duplicate across every architecture.
9 */
10
11#include <linux/capability.h>
12#include <linux/export.h>
13#include <linux/sched.h>
14#include <linux/sched/mm.h>
15#include <linux/sched/coredump.h>
16#include <linux/sched/task.h>
17#include <linux/errno.h>
18#include <linux/mm.h>
19#include <linux/highmem.h>
20#include <linux/pagemap.h>
21#include <linux/ptrace.h>
22#include <linux/security.h>
23#include <linux/signal.h>
24#include <linux/uio.h>
25#include <linux/audit.h>
26#include <linux/pid_namespace.h>
27#include <linux/syscalls.h>
28#include <linux/uaccess.h>
29#include <linux/regset.h>
30#include <linux/hw_breakpoint.h>
31#include <linux/cn_proc.h>
32#include <linux/compat.h>
33#include <linux/sched/signal.h>
34#include <linux/minmax.h>
35
36#include <asm/syscall.h> /* for syscall_get_* */
37
38/*
39 * Access another process' address space via ptrace.
40 * Source/target buffer must be kernel space,
41 * Do not walk the page table directly, use get_user_pages
42 */
43int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
44 void *buf, int len, unsigned int gup_flags)
45{
46 struct mm_struct *mm;
47 int ret;
48
49 mm = get_task_mm(tsk);
50 if (!mm)
51 return 0;
52
53 if (!tsk->ptrace ||
54 (current != tsk->parent) ||
55 ((get_dumpable(mm) != SUID_DUMP_USER) &&
56 !ptracer_capable(tsk, mm->user_ns))) {
57 mmput(mm);
58 return 0;
59 }
60
61 ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
62 mmput(mm);
63
64 return ret;
65}
66
67
68void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
69 const struct cred *ptracer_cred)
70{
71 BUG_ON(!list_empty(&child->ptrace_entry));
72 list_add(&child->ptrace_entry, &new_parent->ptraced);
73 child->parent = new_parent;
74 child->ptracer_cred = get_cred(ptracer_cred);
75}
76
77/*
78 * ptrace a task: make the debugger its new parent and
79 * move it to the ptrace list.
80 *
81 * Must be called with the tasklist lock write-held.
82 */
83static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
84{
85 __ptrace_link(child, new_parent, current_cred());
86}
87
88/**
89 * __ptrace_unlink - unlink ptracee and restore its execution state
90 * @child: ptracee to be unlinked
91 *
92 * Remove @child from the ptrace list, move it back to the original parent,
93 * and restore the execution state so that it conforms to the group stop
94 * state.
95 *
96 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
97 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
98 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
99 * If the ptracer is exiting, the ptracee can be in any state.
100 *
101 * After detach, the ptracee should be in a state which conforms to the
102 * group stop. If the group is stopped or in the process of stopping, the
103 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
104 * up from TASK_TRACED.
105 *
106 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
107 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
108 * to but in the opposite direction of what happens while attaching to a
109 * stopped task. However, in this direction, the intermediate RUNNING
110 * state is not hidden even from the current ptracer and if it immediately
111 * re-attaches and performs a WNOHANG wait(2), it may fail.
112 *
113 * CONTEXT:
114 * write_lock_irq(tasklist_lock)
115 */
116void __ptrace_unlink(struct task_struct *child)
117{
118 const struct cred *old_cred;
119 BUG_ON(!child->ptrace);
120
121 clear_task_syscall_work(child, SYSCALL_TRACE);
122#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
123 clear_task_syscall_work(child, SYSCALL_EMU);
124#endif
125
126 child->parent = child->real_parent;
127 list_del_init(&child->ptrace_entry);
128 old_cred = child->ptracer_cred;
129 child->ptracer_cred = NULL;
130 put_cred(old_cred);
131
132 spin_lock(&child->sighand->siglock);
133 child->ptrace = 0;
134 /*
135 * Clear all pending traps and TRAPPING. TRAPPING should be
136 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
137 */
138 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
139 task_clear_jobctl_trapping(child);
140
141 /*
142 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
143 * @child isn't dead.
144 */
145 if (!(child->flags & PF_EXITING) &&
146 (child->signal->flags & SIGNAL_STOP_STOPPED ||
147 child->signal->group_stop_count)) {
148 child->jobctl |= JOBCTL_STOP_PENDING;
149
150 /*
151 * This is only possible if this thread was cloned by the
152 * traced task running in the stopped group, set the signal
153 * for the future reports.
154 * FIXME: we should change ptrace_init_task() to handle this
155 * case.
156 */
157 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
158 child->jobctl |= SIGSTOP;
159 }
160
161 /*
162 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
163 * @child in the butt. Note that @resume should be used iff @child
164 * is in TASK_TRACED; otherwise, we might unduly disrupt
165 * TASK_KILLABLE sleeps.
166 */
167 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
168 ptrace_signal_wake_up(child, true);
169
170 spin_unlock(&child->sighand->siglock);
171}
172
173static bool looks_like_a_spurious_pid(struct task_struct *task)
174{
175 if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
176 return false;
177
178 if (task_pid_vnr(task) == task->ptrace_message)
179 return false;
180 /*
181 * The tracee changed its pid but the PTRACE_EVENT_EXEC event
182 * was not wait()'ed, most probably debugger targets the old
183 * leader which was destroyed in de_thread().
184 */
185 return true;
186}
187
188/* Ensure that nothing can wake it up, even SIGKILL */
189static bool ptrace_freeze_traced(struct task_struct *task)
190{
191 bool ret = false;
192
193 /* Lockless, nobody but us can set this flag */
194 if (task->jobctl & JOBCTL_LISTENING)
195 return ret;
196
197 spin_lock_irq(&task->sighand->siglock);
198 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
199 !__fatal_signal_pending(task)) {
200 WRITE_ONCE(task->__state, __TASK_TRACED);
201 ret = true;
202 }
203 spin_unlock_irq(&task->sighand->siglock);
204
205 return ret;
206}
207
208static void ptrace_unfreeze_traced(struct task_struct *task)
209{
210 if (READ_ONCE(task->__state) != __TASK_TRACED)
211 return;
212
213 WARN_ON(!task->ptrace || task->parent != current);
214
215 /*
216 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
217 * Recheck state under the lock to close this race.
218 */
219 spin_lock_irq(&task->sighand->siglock);
220 if (READ_ONCE(task->__state) == __TASK_TRACED) {
221 if (__fatal_signal_pending(task))
222 wake_up_state(task, __TASK_TRACED);
223 else
224 WRITE_ONCE(task->__state, TASK_TRACED);
225 }
226 spin_unlock_irq(&task->sighand->siglock);
227}
228
229/**
230 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
231 * @child: ptracee to check for
232 * @ignore_state: don't check whether @child is currently %TASK_TRACED
233 *
234 * Check whether @child is being ptraced by %current and ready for further
235 * ptrace operations. If @ignore_state is %false, @child also should be in
236 * %TASK_TRACED state and on return the child is guaranteed to be traced
237 * and not executing. If @ignore_state is %true, @child can be in any
238 * state.
239 *
240 * CONTEXT:
241 * Grabs and releases tasklist_lock and @child->sighand->siglock.
242 *
243 * RETURNS:
244 * 0 on success, -ESRCH if %child is not ready.
245 */
246static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
247{
248 int ret = -ESRCH;
249
250 /*
251 * We take the read lock around doing both checks to close a
252 * possible race where someone else was tracing our child and
253 * detached between these two checks. After this locked check,
254 * we are sure that this is our traced child and that can only
255 * be changed by us so it's not changing right after this.
256 */
257 read_lock(&tasklist_lock);
258 if (child->ptrace && child->parent == current) {
259 WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED);
260 /*
261 * child->sighand can't be NULL, release_task()
262 * does ptrace_unlink() before __exit_signal().
263 */
264 if (ignore_state || ptrace_freeze_traced(child))
265 ret = 0;
266 }
267 read_unlock(&tasklist_lock);
268
269 if (!ret && !ignore_state) {
270 if (!wait_task_inactive(child, __TASK_TRACED)) {
271 /*
272 * This can only happen if may_ptrace_stop() fails and
273 * ptrace_stop() changes ->state back to TASK_RUNNING,
274 * so we should not worry about leaking __TASK_TRACED.
275 */
276 WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED);
277 ret = -ESRCH;
278 }
279 }
280
281 return ret;
282}
283
284static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
285{
286 if (mode & PTRACE_MODE_NOAUDIT)
287 return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
288 return ns_capable(ns, CAP_SYS_PTRACE);
289}
290
291/* Returns 0 on success, -errno on denial. */
292static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
293{
294 const struct cred *cred = current_cred(), *tcred;
295 struct mm_struct *mm;
296 kuid_t caller_uid;
297 kgid_t caller_gid;
298
299 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
300 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
301 return -EPERM;
302 }
303
304 /* May we inspect the given task?
305 * This check is used both for attaching with ptrace
306 * and for allowing access to sensitive information in /proc.
307 *
308 * ptrace_attach denies several cases that /proc allows
309 * because setting up the necessary parent/child relationship
310 * or halting the specified task is impossible.
311 */
312
313 /* Don't let security modules deny introspection */
314 if (same_thread_group(task, current))
315 return 0;
316 rcu_read_lock();
317 if (mode & PTRACE_MODE_FSCREDS) {
318 caller_uid = cred->fsuid;
319 caller_gid = cred->fsgid;
320 } else {
321 /*
322 * Using the euid would make more sense here, but something
323 * in userland might rely on the old behavior, and this
324 * shouldn't be a security problem since
325 * PTRACE_MODE_REALCREDS implies that the caller explicitly
326 * used a syscall that requests access to another process
327 * (and not a filesystem syscall to procfs).
328 */
329 caller_uid = cred->uid;
330 caller_gid = cred->gid;
331 }
332 tcred = __task_cred(task);
333 if (uid_eq(caller_uid, tcred->euid) &&
334 uid_eq(caller_uid, tcred->suid) &&
335 uid_eq(caller_uid, tcred->uid) &&
336 gid_eq(caller_gid, tcred->egid) &&
337 gid_eq(caller_gid, tcred->sgid) &&
338 gid_eq(caller_gid, tcred->gid))
339 goto ok;
340 if (ptrace_has_cap(tcred->user_ns, mode))
341 goto ok;
342 rcu_read_unlock();
343 return -EPERM;
344ok:
345 rcu_read_unlock();
346 /*
347 * If a task drops privileges and becomes nondumpable (through a syscall
348 * like setresuid()) while we are trying to access it, we must ensure
349 * that the dumpability is read after the credentials; otherwise,
350 * we may be able to attach to a task that we shouldn't be able to
351 * attach to (as if the task had dropped privileges without becoming
352 * nondumpable).
353 * Pairs with a write barrier in commit_creds().
354 */
355 smp_rmb();
356 mm = task->mm;
357 if (mm &&
358 ((get_dumpable(mm) != SUID_DUMP_USER) &&
359 !ptrace_has_cap(mm->user_ns, mode)))
360 return -EPERM;
361
362 return security_ptrace_access_check(task, mode);
363}
364
365bool ptrace_may_access(struct task_struct *task, unsigned int mode)
366{
367 int err;
368 task_lock(task);
369 err = __ptrace_may_access(task, mode);
370 task_unlock(task);
371 return !err;
372}
373
374static int ptrace_attach(struct task_struct *task, long request,
375 unsigned long addr,
376 unsigned long flags)
377{
378 bool seize = (request == PTRACE_SEIZE);
379 int retval;
380
381 retval = -EIO;
382 if (seize) {
383 if (addr != 0)
384 goto out;
385 if (flags & ~(unsigned long)PTRACE_O_MASK)
386 goto out;
387 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
388 } else {
389 flags = PT_PTRACED;
390 }
391
392 audit_ptrace(task);
393
394 retval = -EPERM;
395 if (unlikely(task->flags & PF_KTHREAD))
396 goto out;
397 if (same_thread_group(task, current))
398 goto out;
399
400 /*
401 * Protect exec's credential calculations against our interference;
402 * SUID, SGID and LSM creds get determined differently
403 * under ptrace.
404 */
405 retval = -ERESTARTNOINTR;
406 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
407 goto out;
408
409 task_lock(task);
410 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
411 task_unlock(task);
412 if (retval)
413 goto unlock_creds;
414
415 write_lock_irq(&tasklist_lock);
416 retval = -EPERM;
417 if (unlikely(task->exit_state))
418 goto unlock_tasklist;
419 if (task->ptrace)
420 goto unlock_tasklist;
421
422 if (seize)
423 flags |= PT_SEIZED;
424 task->ptrace = flags;
425
426 ptrace_link(task, current);
427
428 /* SEIZE doesn't trap tracee on attach */
429 if (!seize)
430 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
431
432 spin_lock(&task->sighand->siglock);
433
434 /*
435 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
436 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
437 * will be cleared if the child completes the transition or any
438 * event which clears the group stop states happens. We'll wait
439 * for the transition to complete before returning from this
440 * function.
441 *
442 * This hides STOPPED -> RUNNING -> TRACED transition from the
443 * attaching thread but a different thread in the same group can
444 * still observe the transient RUNNING state. IOW, if another
445 * thread's WNOHANG wait(2) on the stopped tracee races against
446 * ATTACH, the wait(2) may fail due to the transient RUNNING.
447 *
448 * The following task_is_stopped() test is safe as both transitions
449 * in and out of STOPPED are protected by siglock.
450 */
451 if (task_is_stopped(task) &&
452 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
453 signal_wake_up_state(task, __TASK_STOPPED);
454
455 spin_unlock(&task->sighand->siglock);
456
457 retval = 0;
458unlock_tasklist:
459 write_unlock_irq(&tasklist_lock);
460unlock_creds:
461 mutex_unlock(&task->signal->cred_guard_mutex);
462out:
463 if (!retval) {
464 /*
465 * We do not bother to change retval or clear JOBCTL_TRAPPING
466 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
467 * not return to user-mode, it will exit and clear this bit in
468 * __ptrace_unlink() if it wasn't already cleared by the tracee;
469 * and until then nobody can ptrace this task.
470 */
471 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
472 proc_ptrace_connector(task, PTRACE_ATTACH);
473 }
474
475 return retval;
476}
477
478/**
479 * ptrace_traceme -- helper for PTRACE_TRACEME
480 *
481 * Performs checks and sets PT_PTRACED.
482 * Should be used by all ptrace implementations for PTRACE_TRACEME.
483 */
484static int ptrace_traceme(void)
485{
486 int ret = -EPERM;
487
488 write_lock_irq(&tasklist_lock);
489 /* Are we already being traced? */
490 if (!current->ptrace) {
491 ret = security_ptrace_traceme(current->parent);
492 /*
493 * Check PF_EXITING to ensure ->real_parent has not passed
494 * exit_ptrace(). Otherwise we don't report the error but
495 * pretend ->real_parent untraces us right after return.
496 */
497 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
498 current->ptrace = PT_PTRACED;
499 ptrace_link(current, current->real_parent);
500 }
501 }
502 write_unlock_irq(&tasklist_lock);
503
504 return ret;
505}
506
507/*
508 * Called with irqs disabled, returns true if childs should reap themselves.
509 */
510static int ignoring_children(struct sighand_struct *sigh)
511{
512 int ret;
513 spin_lock(&sigh->siglock);
514 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
515 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
516 spin_unlock(&sigh->siglock);
517 return ret;
518}
519
520/*
521 * Called with tasklist_lock held for writing.
522 * Unlink a traced task, and clean it up if it was a traced zombie.
523 * Return true if it needs to be reaped with release_task().
524 * (We can't call release_task() here because we already hold tasklist_lock.)
525 *
526 * If it's a zombie, our attachedness prevented normal parent notification
527 * or self-reaping. Do notification now if it would have happened earlier.
528 * If it should reap itself, return true.
529 *
530 * If it's our own child, there is no notification to do. But if our normal
531 * children self-reap, then this child was prevented by ptrace and we must
532 * reap it now, in that case we must also wake up sub-threads sleeping in
533 * do_wait().
534 */
535static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
536{
537 bool dead;
538
539 __ptrace_unlink(p);
540
541 if (p->exit_state != EXIT_ZOMBIE)
542 return false;
543
544 dead = !thread_group_leader(p);
545
546 if (!dead && thread_group_empty(p)) {
547 if (!same_thread_group(p->real_parent, tracer))
548 dead = do_notify_parent(p, p->exit_signal);
549 else if (ignoring_children(tracer->sighand)) {
550 __wake_up_parent(p, tracer);
551 dead = true;
552 }
553 }
554 /* Mark it as in the process of being reaped. */
555 if (dead)
556 p->exit_state = EXIT_DEAD;
557 return dead;
558}
559
560static int ptrace_detach(struct task_struct *child, unsigned int data)
561{
562 if (!valid_signal(data))
563 return -EIO;
564
565 /* Architecture-specific hardware disable .. */
566 ptrace_disable(child);
567
568 write_lock_irq(&tasklist_lock);
569 /*
570 * We rely on ptrace_freeze_traced(). It can't be killed and
571 * untraced by another thread, it can't be a zombie.
572 */
573 WARN_ON(!child->ptrace || child->exit_state);
574 /*
575 * tasklist_lock avoids the race with wait_task_stopped(), see
576 * the comment in ptrace_resume().
577 */
578 child->exit_code = data;
579 __ptrace_detach(current, child);
580 write_unlock_irq(&tasklist_lock);
581
582 proc_ptrace_connector(child, PTRACE_DETACH);
583
584 return 0;
585}
586
587/*
588 * Detach all tasks we were using ptrace on. Called with tasklist held
589 * for writing.
590 */
591void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
592{
593 struct task_struct *p, *n;
594
595 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
596 if (unlikely(p->ptrace & PT_EXITKILL))
597 send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
598
599 if (__ptrace_detach(tracer, p))
600 list_add(&p->ptrace_entry, dead);
601 }
602}
603
604int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
605{
606 int copied = 0;
607
608 while (len > 0) {
609 char buf[128];
610 int this_len, retval;
611
612 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
613 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
614
615 if (!retval) {
616 if (copied)
617 break;
618 return -EIO;
619 }
620 if (copy_to_user(dst, buf, retval))
621 return -EFAULT;
622 copied += retval;
623 src += retval;
624 dst += retval;
625 len -= retval;
626 }
627 return copied;
628}
629
630int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
631{
632 int copied = 0;
633
634 while (len > 0) {
635 char buf[128];
636 int this_len, retval;
637
638 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
639 if (copy_from_user(buf, src, this_len))
640 return -EFAULT;
641 retval = ptrace_access_vm(tsk, dst, buf, this_len,
642 FOLL_FORCE | FOLL_WRITE);
643 if (!retval) {
644 if (copied)
645 break;
646 return -EIO;
647 }
648 copied += retval;
649 src += retval;
650 dst += retval;
651 len -= retval;
652 }
653 return copied;
654}
655
656static int ptrace_setoptions(struct task_struct *child, unsigned long data)
657{
658 unsigned flags;
659
660 if (data & ~(unsigned long)PTRACE_O_MASK)
661 return -EINVAL;
662
663 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
664 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
665 !IS_ENABLED(CONFIG_SECCOMP))
666 return -EINVAL;
667
668 if (!capable(CAP_SYS_ADMIN))
669 return -EPERM;
670
671 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
672 current->ptrace & PT_SUSPEND_SECCOMP)
673 return -EPERM;
674 }
675
676 /* Avoid intermediate state when all opts are cleared */
677 flags = child->ptrace;
678 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
679 flags |= (data << PT_OPT_FLAG_SHIFT);
680 child->ptrace = flags;
681
682 return 0;
683}
684
685static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
686{
687 unsigned long flags;
688 int error = -ESRCH;
689
690 if (lock_task_sighand(child, &flags)) {
691 error = -EINVAL;
692 if (likely(child->last_siginfo != NULL)) {
693 copy_siginfo(info, child->last_siginfo);
694 error = 0;
695 }
696 unlock_task_sighand(child, &flags);
697 }
698 return error;
699}
700
701static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
702{
703 unsigned long flags;
704 int error = -ESRCH;
705
706 if (lock_task_sighand(child, &flags)) {
707 error = -EINVAL;
708 if (likely(child->last_siginfo != NULL)) {
709 copy_siginfo(child->last_siginfo, info);
710 error = 0;
711 }
712 unlock_task_sighand(child, &flags);
713 }
714 return error;
715}
716
717static int ptrace_peek_siginfo(struct task_struct *child,
718 unsigned long addr,
719 unsigned long data)
720{
721 struct ptrace_peeksiginfo_args arg;
722 struct sigpending *pending;
723 struct sigqueue *q;
724 int ret, i;
725
726 ret = copy_from_user(&arg, (void __user *) addr,
727 sizeof(struct ptrace_peeksiginfo_args));
728 if (ret)
729 return -EFAULT;
730
731 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
732 return -EINVAL; /* unknown flags */
733
734 if (arg.nr < 0)
735 return -EINVAL;
736
737 /* Ensure arg.off fits in an unsigned long */
738 if (arg.off > ULONG_MAX)
739 return 0;
740
741 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
742 pending = &child->signal->shared_pending;
743 else
744 pending = &child->pending;
745
746 for (i = 0; i < arg.nr; ) {
747 kernel_siginfo_t info;
748 unsigned long off = arg.off + i;
749 bool found = false;
750
751 spin_lock_irq(&child->sighand->siglock);
752 list_for_each_entry(q, &pending->list, list) {
753 if (!off--) {
754 found = true;
755 copy_siginfo(&info, &q->info);
756 break;
757 }
758 }
759 spin_unlock_irq(&child->sighand->siglock);
760
761 if (!found) /* beyond the end of the list */
762 break;
763
764#ifdef CONFIG_COMPAT
765 if (unlikely(in_compat_syscall())) {
766 compat_siginfo_t __user *uinfo = compat_ptr(data);
767
768 if (copy_siginfo_to_user32(uinfo, &info)) {
769 ret = -EFAULT;
770 break;
771 }
772
773 } else
774#endif
775 {
776 siginfo_t __user *uinfo = (siginfo_t __user *) data;
777
778 if (copy_siginfo_to_user(uinfo, &info)) {
779 ret = -EFAULT;
780 break;
781 }
782 }
783
784 data += sizeof(siginfo_t);
785 i++;
786
787 if (signal_pending(current))
788 break;
789
790 cond_resched();
791 }
792
793 if (i > 0)
794 return i;
795
796 return ret;
797}
798
799#ifdef CONFIG_RSEQ
800static long ptrace_get_rseq_configuration(struct task_struct *task,
801 unsigned long size, void __user *data)
802{
803 struct ptrace_rseq_configuration conf = {
804 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
805 .rseq_abi_size = sizeof(*task->rseq),
806 .signature = task->rseq_sig,
807 .flags = 0,
808 };
809
810 size = min_t(unsigned long, size, sizeof(conf));
811 if (copy_to_user(data, &conf, size))
812 return -EFAULT;
813 return sizeof(conf);
814}
815#endif
816
817#ifdef PTRACE_SINGLESTEP
818#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
819#else
820#define is_singlestep(request) 0
821#endif
822
823#ifdef PTRACE_SINGLEBLOCK
824#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
825#else
826#define is_singleblock(request) 0
827#endif
828
829#ifdef PTRACE_SYSEMU
830#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
831#else
832#define is_sysemu_singlestep(request) 0
833#endif
834
835static int ptrace_resume(struct task_struct *child, long request,
836 unsigned long data)
837{
838 bool need_siglock;
839
840 if (!valid_signal(data))
841 return -EIO;
842
843 if (request == PTRACE_SYSCALL)
844 set_task_syscall_work(child, SYSCALL_TRACE);
845 else
846 clear_task_syscall_work(child, SYSCALL_TRACE);
847
848#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
849 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
850 set_task_syscall_work(child, SYSCALL_EMU);
851 else
852 clear_task_syscall_work(child, SYSCALL_EMU);
853#endif
854
855 if (is_singleblock(request)) {
856 if (unlikely(!arch_has_block_step()))
857 return -EIO;
858 user_enable_block_step(child);
859 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
860 if (unlikely(!arch_has_single_step()))
861 return -EIO;
862 user_enable_single_step(child);
863 } else {
864 user_disable_single_step(child);
865 }
866
867 /*
868 * Change ->exit_code and ->state under siglock to avoid the race
869 * with wait_task_stopped() in between; a non-zero ->exit_code will
870 * wrongly look like another report from tracee.
871 *
872 * Note that we need siglock even if ->exit_code == data and/or this
873 * status was not reported yet, the new status must not be cleared by
874 * wait_task_stopped() after resume.
875 *
876 * If data == 0 we do not care if wait_task_stopped() reports the old
877 * status and clears the code too; this can't race with the tracee, it
878 * takes siglock after resume.
879 */
880 need_siglock = data && !thread_group_empty(current);
881 if (need_siglock)
882 spin_lock_irq(&child->sighand->siglock);
883 child->exit_code = data;
884 wake_up_state(child, __TASK_TRACED);
885 if (need_siglock)
886 spin_unlock_irq(&child->sighand->siglock);
887
888 return 0;
889}
890
891#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
892
893static const struct user_regset *
894find_regset(const struct user_regset_view *view, unsigned int type)
895{
896 const struct user_regset *regset;
897 int n;
898
899 for (n = 0; n < view->n; ++n) {
900 regset = view->regsets + n;
901 if (regset->core_note_type == type)
902 return regset;
903 }
904
905 return NULL;
906}
907
908static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
909 struct iovec *kiov)
910{
911 const struct user_regset_view *view = task_user_regset_view(task);
912 const struct user_regset *regset = find_regset(view, type);
913 int regset_no;
914
915 if (!regset || (kiov->iov_len % regset->size) != 0)
916 return -EINVAL;
917
918 regset_no = regset - view->regsets;
919 kiov->iov_len = min(kiov->iov_len,
920 (__kernel_size_t) (regset->n * regset->size));
921
922 if (req == PTRACE_GETREGSET)
923 return copy_regset_to_user(task, view, regset_no, 0,
924 kiov->iov_len, kiov->iov_base);
925 else
926 return copy_regset_from_user(task, view, regset_no, 0,
927 kiov->iov_len, kiov->iov_base);
928}
929
930/*
931 * This is declared in linux/regset.h and defined in machine-dependent
932 * code. We put the export here, near the primary machine-neutral use,
933 * to ensure no machine forgets it.
934 */
935EXPORT_SYMBOL_GPL(task_user_regset_view);
936
937static unsigned long
938ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
939 struct ptrace_syscall_info *info)
940{
941 unsigned long args[ARRAY_SIZE(info->entry.args)];
942 int i;
943
944 info->op = PTRACE_SYSCALL_INFO_ENTRY;
945 info->entry.nr = syscall_get_nr(child, regs);
946 syscall_get_arguments(child, regs, args);
947 for (i = 0; i < ARRAY_SIZE(args); i++)
948 info->entry.args[i] = args[i];
949
950 /* args is the last field in struct ptrace_syscall_info.entry */
951 return offsetofend(struct ptrace_syscall_info, entry.args);
952}
953
954static unsigned long
955ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
956 struct ptrace_syscall_info *info)
957{
958 /*
959 * As struct ptrace_syscall_info.entry is currently a subset
960 * of struct ptrace_syscall_info.seccomp, it makes sense to
961 * initialize that subset using ptrace_get_syscall_info_entry().
962 * This can be reconsidered in the future if these structures
963 * diverge significantly enough.
964 */
965 ptrace_get_syscall_info_entry(child, regs, info);
966 info->op = PTRACE_SYSCALL_INFO_SECCOMP;
967 info->seccomp.ret_data = child->ptrace_message;
968
969 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
970 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
971}
972
973static unsigned long
974ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
975 struct ptrace_syscall_info *info)
976{
977 info->op = PTRACE_SYSCALL_INFO_EXIT;
978 info->exit.rval = syscall_get_error(child, regs);
979 info->exit.is_error = !!info->exit.rval;
980 if (!info->exit.is_error)
981 info->exit.rval = syscall_get_return_value(child, regs);
982
983 /* is_error is the last field in struct ptrace_syscall_info.exit */
984 return offsetofend(struct ptrace_syscall_info, exit.is_error);
985}
986
987static int
988ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
989 void __user *datavp)
990{
991 struct pt_regs *regs = task_pt_regs(child);
992 struct ptrace_syscall_info info = {
993 .op = PTRACE_SYSCALL_INFO_NONE,
994 .arch = syscall_get_arch(child),
995 .instruction_pointer = instruction_pointer(regs),
996 .stack_pointer = user_stack_pointer(regs),
997 };
998 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
999 unsigned long write_size;
1000
1001 /*
1002 * This does not need lock_task_sighand() to access
1003 * child->last_siginfo because ptrace_freeze_traced()
1004 * called earlier by ptrace_check_attach() ensures that
1005 * the tracee cannot go away and clear its last_siginfo.
1006 */
1007 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
1008 case SIGTRAP | 0x80:
1009 switch (child->ptrace_message) {
1010 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
1011 actual_size = ptrace_get_syscall_info_entry(child, regs,
1012 &info);
1013 break;
1014 case PTRACE_EVENTMSG_SYSCALL_EXIT:
1015 actual_size = ptrace_get_syscall_info_exit(child, regs,
1016 &info);
1017 break;
1018 }
1019 break;
1020 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
1021 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
1022 &info);
1023 break;
1024 }
1025
1026 write_size = min(actual_size, user_size);
1027 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
1028}
1029#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
1030
1031int ptrace_request(struct task_struct *child, long request,
1032 unsigned long addr, unsigned long data)
1033{
1034 bool seized = child->ptrace & PT_SEIZED;
1035 int ret = -EIO;
1036 kernel_siginfo_t siginfo, *si;
1037 void __user *datavp = (void __user *) data;
1038 unsigned long __user *datalp = datavp;
1039 unsigned long flags;
1040
1041 switch (request) {
1042 case PTRACE_PEEKTEXT:
1043 case PTRACE_PEEKDATA:
1044 return generic_ptrace_peekdata(child, addr, data);
1045 case PTRACE_POKETEXT:
1046 case PTRACE_POKEDATA:
1047 return generic_ptrace_pokedata(child, addr, data);
1048
1049#ifdef PTRACE_OLDSETOPTIONS
1050 case PTRACE_OLDSETOPTIONS:
1051#endif
1052 case PTRACE_SETOPTIONS:
1053 ret = ptrace_setoptions(child, data);
1054 break;
1055 case PTRACE_GETEVENTMSG:
1056 ret = put_user(child->ptrace_message, datalp);
1057 break;
1058
1059 case PTRACE_PEEKSIGINFO:
1060 ret = ptrace_peek_siginfo(child, addr, data);
1061 break;
1062
1063 case PTRACE_GETSIGINFO:
1064 ret = ptrace_getsiginfo(child, &siginfo);
1065 if (!ret)
1066 ret = copy_siginfo_to_user(datavp, &siginfo);
1067 break;
1068
1069 case PTRACE_SETSIGINFO:
1070 ret = copy_siginfo_from_user(&siginfo, datavp);
1071 if (!ret)
1072 ret = ptrace_setsiginfo(child, &siginfo);
1073 break;
1074
1075 case PTRACE_GETSIGMASK: {
1076 sigset_t *mask;
1077
1078 if (addr != sizeof(sigset_t)) {
1079 ret = -EINVAL;
1080 break;
1081 }
1082
1083 if (test_tsk_restore_sigmask(child))
1084 mask = &child->saved_sigmask;
1085 else
1086 mask = &child->blocked;
1087
1088 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
1089 ret = -EFAULT;
1090 else
1091 ret = 0;
1092
1093 break;
1094 }
1095
1096 case PTRACE_SETSIGMASK: {
1097 sigset_t new_set;
1098
1099 if (addr != sizeof(sigset_t)) {
1100 ret = -EINVAL;
1101 break;
1102 }
1103
1104 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1105 ret = -EFAULT;
1106 break;
1107 }
1108
1109 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1110
1111 /*
1112 * Every thread does recalc_sigpending() after resume, so
1113 * retarget_shared_pending() and recalc_sigpending() are not
1114 * called here.
1115 */
1116 spin_lock_irq(&child->sighand->siglock);
1117 child->blocked = new_set;
1118 spin_unlock_irq(&child->sighand->siglock);
1119
1120 clear_tsk_restore_sigmask(child);
1121
1122 ret = 0;
1123 break;
1124 }
1125
1126 case PTRACE_INTERRUPT:
1127 /*
1128 * Stop tracee without any side-effect on signal or job
1129 * control. At least one trap is guaranteed to happen
1130 * after this request. If @child is already trapped, the
1131 * current trap is not disturbed and another trap will
1132 * happen after the current trap is ended with PTRACE_CONT.
1133 *
1134 * The actual trap might not be PTRACE_EVENT_STOP trap but
1135 * the pending condition is cleared regardless.
1136 */
1137 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1138 break;
1139
1140 /*
1141 * INTERRUPT doesn't disturb existing trap sans one
1142 * exception. If ptracer issued LISTEN for the current
1143 * STOP, this INTERRUPT should clear LISTEN and re-trap
1144 * tracee into STOP.
1145 */
1146 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
1147 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
1148
1149 unlock_task_sighand(child, &flags);
1150 ret = 0;
1151 break;
1152
1153 case PTRACE_LISTEN:
1154 /*
1155 * Listen for events. Tracee must be in STOP. It's not
1156 * resumed per-se but is not considered to be in TRACED by
1157 * wait(2) or ptrace(2). If an async event (e.g. group
1158 * stop state change) happens, tracee will enter STOP trap
1159 * again. Alternatively, ptracer can issue INTERRUPT to
1160 * finish listening and re-trap tracee into STOP.
1161 */
1162 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1163 break;
1164
1165 si = child->last_siginfo;
1166 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1167 child->jobctl |= JOBCTL_LISTENING;
1168 /*
1169 * If NOTIFY is set, it means event happened between
1170 * start of this trap and now. Trigger re-trap.
1171 */
1172 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1173 ptrace_signal_wake_up(child, true);
1174 ret = 0;
1175 }
1176 unlock_task_sighand(child, &flags);
1177 break;
1178
1179 case PTRACE_DETACH: /* detach a process that was attached. */
1180 ret = ptrace_detach(child, data);
1181 break;
1182
1183#ifdef CONFIG_BINFMT_ELF_FDPIC
1184 case PTRACE_GETFDPIC: {
1185 struct mm_struct *mm = get_task_mm(child);
1186 unsigned long tmp = 0;
1187
1188 ret = -ESRCH;
1189 if (!mm)
1190 break;
1191
1192 switch (addr) {
1193 case PTRACE_GETFDPIC_EXEC:
1194 tmp = mm->context.exec_fdpic_loadmap;
1195 break;
1196 case PTRACE_GETFDPIC_INTERP:
1197 tmp = mm->context.interp_fdpic_loadmap;
1198 break;
1199 default:
1200 break;
1201 }
1202 mmput(mm);
1203
1204 ret = put_user(tmp, datalp);
1205 break;
1206 }
1207#endif
1208
1209#ifdef PTRACE_SINGLESTEP
1210 case PTRACE_SINGLESTEP:
1211#endif
1212#ifdef PTRACE_SINGLEBLOCK
1213 case PTRACE_SINGLEBLOCK:
1214#endif
1215#ifdef PTRACE_SYSEMU
1216 case PTRACE_SYSEMU:
1217 case PTRACE_SYSEMU_SINGLESTEP:
1218#endif
1219 case PTRACE_SYSCALL:
1220 case PTRACE_CONT:
1221 return ptrace_resume(child, request, data);
1222
1223 case PTRACE_KILL:
1224 if (child->exit_state) /* already dead */
1225 return 0;
1226 return ptrace_resume(child, request, SIGKILL);
1227
1228#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1229 case PTRACE_GETREGSET:
1230 case PTRACE_SETREGSET: {
1231 struct iovec kiov;
1232 struct iovec __user *uiov = datavp;
1233
1234 if (!access_ok(uiov, sizeof(*uiov)))
1235 return -EFAULT;
1236
1237 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1238 __get_user(kiov.iov_len, &uiov->iov_len))
1239 return -EFAULT;
1240
1241 ret = ptrace_regset(child, request, addr, &kiov);
1242 if (!ret)
1243 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1244 break;
1245 }
1246
1247 case PTRACE_GET_SYSCALL_INFO:
1248 ret = ptrace_get_syscall_info(child, addr, datavp);
1249 break;
1250#endif
1251
1252 case PTRACE_SECCOMP_GET_FILTER:
1253 ret = seccomp_get_filter(child, addr, datavp);
1254 break;
1255
1256 case PTRACE_SECCOMP_GET_METADATA:
1257 ret = seccomp_get_metadata(child, addr, datavp);
1258 break;
1259
1260#ifdef CONFIG_RSEQ
1261 case PTRACE_GET_RSEQ_CONFIGURATION:
1262 ret = ptrace_get_rseq_configuration(child, addr, datavp);
1263 break;
1264#endif
1265
1266 default:
1267 break;
1268 }
1269
1270 return ret;
1271}
1272
1273#ifndef arch_ptrace_attach
1274#define arch_ptrace_attach(child) do { } while (0)
1275#endif
1276
1277SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1278 unsigned long, data)
1279{
1280 struct task_struct *child;
1281 long ret;
1282
1283 if (request == PTRACE_TRACEME) {
1284 ret = ptrace_traceme();
1285 if (!ret)
1286 arch_ptrace_attach(current);
1287 goto out;
1288 }
1289
1290 child = find_get_task_by_vpid(pid);
1291 if (!child) {
1292 ret = -ESRCH;
1293 goto out;
1294 }
1295
1296 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1297 ret = ptrace_attach(child, request, addr, data);
1298 /*
1299 * Some architectures need to do book-keeping after
1300 * a ptrace attach.
1301 */
1302 if (!ret)
1303 arch_ptrace_attach(child);
1304 goto out_put_task_struct;
1305 }
1306
1307 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1308 request == PTRACE_INTERRUPT);
1309 if (ret < 0)
1310 goto out_put_task_struct;
1311
1312 ret = arch_ptrace(child, request, addr, data);
1313 if (ret || request != PTRACE_DETACH)
1314 ptrace_unfreeze_traced(child);
1315
1316 out_put_task_struct:
1317 put_task_struct(child);
1318 out:
1319 return ret;
1320}
1321
1322int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1323 unsigned long data)
1324{
1325 unsigned long tmp;
1326 int copied;
1327
1328 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1329 if (copied != sizeof(tmp))
1330 return -EIO;
1331 return put_user(tmp, (unsigned long __user *)data);
1332}
1333
1334int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1335 unsigned long data)
1336{
1337 int copied;
1338
1339 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1340 FOLL_FORCE | FOLL_WRITE);
1341 return (copied == sizeof(data)) ? 0 : -EIO;
1342}
1343
1344#if defined CONFIG_COMPAT
1345
1346int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1347 compat_ulong_t addr, compat_ulong_t data)
1348{
1349 compat_ulong_t __user *datap = compat_ptr(data);
1350 compat_ulong_t word;
1351 kernel_siginfo_t siginfo;
1352 int ret;
1353
1354 switch (request) {
1355 case PTRACE_PEEKTEXT:
1356 case PTRACE_PEEKDATA:
1357 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1358 FOLL_FORCE);
1359 if (ret != sizeof(word))
1360 ret = -EIO;
1361 else
1362 ret = put_user(word, datap);
1363 break;
1364
1365 case PTRACE_POKETEXT:
1366 case PTRACE_POKEDATA:
1367 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1368 FOLL_FORCE | FOLL_WRITE);
1369 ret = (ret != sizeof(data) ? -EIO : 0);
1370 break;
1371
1372 case PTRACE_GETEVENTMSG:
1373 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1374 break;
1375
1376 case PTRACE_GETSIGINFO:
1377 ret = ptrace_getsiginfo(child, &siginfo);
1378 if (!ret)
1379 ret = copy_siginfo_to_user32(
1380 (struct compat_siginfo __user *) datap,
1381 &siginfo);
1382 break;
1383
1384 case PTRACE_SETSIGINFO:
1385 ret = copy_siginfo_from_user32(
1386 &siginfo, (struct compat_siginfo __user *) datap);
1387 if (!ret)
1388 ret = ptrace_setsiginfo(child, &siginfo);
1389 break;
1390#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1391 case PTRACE_GETREGSET:
1392 case PTRACE_SETREGSET:
1393 {
1394 struct iovec kiov;
1395 struct compat_iovec __user *uiov =
1396 (struct compat_iovec __user *) datap;
1397 compat_uptr_t ptr;
1398 compat_size_t len;
1399
1400 if (!access_ok(uiov, sizeof(*uiov)))
1401 return -EFAULT;
1402
1403 if (__get_user(ptr, &uiov->iov_base) ||
1404 __get_user(len, &uiov->iov_len))
1405 return -EFAULT;
1406
1407 kiov.iov_base = compat_ptr(ptr);
1408 kiov.iov_len = len;
1409
1410 ret = ptrace_regset(child, request, addr, &kiov);
1411 if (!ret)
1412 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1413 break;
1414 }
1415#endif
1416
1417 default:
1418 ret = ptrace_request(child, request, addr, data);
1419 }
1420
1421 return ret;
1422}
1423
1424COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1425 compat_long_t, addr, compat_long_t, data)
1426{
1427 struct task_struct *child;
1428 long ret;
1429
1430 if (request == PTRACE_TRACEME) {
1431 ret = ptrace_traceme();
1432 goto out;
1433 }
1434
1435 child = find_get_task_by_vpid(pid);
1436 if (!child) {
1437 ret = -ESRCH;
1438 goto out;
1439 }
1440
1441 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1442 ret = ptrace_attach(child, request, addr, data);
1443 /*
1444 * Some architectures need to do book-keeping after
1445 * a ptrace attach.
1446 */
1447 if (!ret)
1448 arch_ptrace_attach(child);
1449 goto out_put_task_struct;
1450 }
1451
1452 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1453 request == PTRACE_INTERRUPT);
1454 if (!ret) {
1455 ret = compat_arch_ptrace(child, request, addr, data);
1456 if (ret || request != PTRACE_DETACH)
1457 ptrace_unfreeze_traced(child);
1458 }
1459
1460 out_put_task_struct:
1461 put_task_struct(child);
1462 out:
1463 return ret;
1464}
1465#endif /* CONFIG_COMPAT */