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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 * Access another process' address space via ptrace.
32 * Source/target buffer must be kernel space,
33 * Do not walk the page table directly, use get_user_pages
34 */
35int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
36 void *buf, int len, unsigned int gup_flags)
37{
38 struct mm_struct *mm;
39 int ret;
40
41 mm = get_task_mm(tsk);
42 if (!mm)
43 return 0;
44
45 if (!tsk->ptrace ||
46 (current != tsk->parent) ||
47 ((get_dumpable(mm) != SUID_DUMP_USER) &&
48 !ptracer_capable(tsk, mm->user_ns))) {
49 mmput(mm);
50 return 0;
51 }
52
53 ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
54 mmput(mm);
55
56 return ret;
57}
58
59
60/*
61 * ptrace a task: make the debugger its new parent and
62 * move it to the ptrace list.
63 *
64 * Must be called with the tasklist lock write-held.
65 */
66void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
67{
68 BUG_ON(!list_empty(&child->ptrace_entry));
69 list_add(&child->ptrace_entry, &new_parent->ptraced);
70 child->parent = new_parent;
71 rcu_read_lock();
72 child->ptracer_cred = get_cred(__task_cred(new_parent));
73 rcu_read_unlock();
74}
75
76/**
77 * __ptrace_unlink - unlink ptracee and restore its execution state
78 * @child: ptracee to be unlinked
79 *
80 * Remove @child from the ptrace list, move it back to the original parent,
81 * and restore the execution state so that it conforms to the group stop
82 * state.
83 *
84 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
85 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
86 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
87 * If the ptracer is exiting, the ptracee can be in any state.
88 *
89 * After detach, the ptracee should be in a state which conforms to the
90 * group stop. If the group is stopped or in the process of stopping, the
91 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
92 * up from TASK_TRACED.
93 *
94 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
95 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
96 * to but in the opposite direction of what happens while attaching to a
97 * stopped task. However, in this direction, the intermediate RUNNING
98 * state is not hidden even from the current ptracer and if it immediately
99 * re-attaches and performs a WNOHANG wait(2), it may fail.
100 *
101 * CONTEXT:
102 * write_lock_irq(tasklist_lock)
103 */
104void __ptrace_unlink(struct task_struct *child)
105{
106 const struct cred *old_cred;
107 BUG_ON(!child->ptrace);
108
109 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
110
111 child->parent = child->real_parent;
112 list_del_init(&child->ptrace_entry);
113 old_cred = child->ptracer_cred;
114 child->ptracer_cred = NULL;
115 put_cred(old_cred);
116
117 spin_lock(&child->sighand->siglock);
118 child->ptrace = 0;
119 /*
120 * Clear all pending traps and TRAPPING. TRAPPING should be
121 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
122 */
123 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
124 task_clear_jobctl_trapping(child);
125
126 /*
127 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
128 * @child isn't dead.
129 */
130 if (!(child->flags & PF_EXITING) &&
131 (child->signal->flags & SIGNAL_STOP_STOPPED ||
132 child->signal->group_stop_count)) {
133 child->jobctl |= JOBCTL_STOP_PENDING;
134
135 /*
136 * This is only possible if this thread was cloned by the
137 * traced task running in the stopped group, set the signal
138 * for the future reports.
139 * FIXME: we should change ptrace_init_task() to handle this
140 * case.
141 */
142 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
143 child->jobctl |= SIGSTOP;
144 }
145
146 /*
147 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
148 * @child in the butt. Note that @resume should be used iff @child
149 * is in TASK_TRACED; otherwise, we might unduly disrupt
150 * TASK_KILLABLE sleeps.
151 */
152 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
153 ptrace_signal_wake_up(child, true);
154
155 spin_unlock(&child->sighand->siglock);
156}
157
158/* Ensure that nothing can wake it up, even SIGKILL */
159static bool ptrace_freeze_traced(struct task_struct *task)
160{
161 bool ret = false;
162
163 /* Lockless, nobody but us can set this flag */
164 if (task->jobctl & JOBCTL_LISTENING)
165 return ret;
166
167 spin_lock_irq(&task->sighand->siglock);
168 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
169 task->state = __TASK_TRACED;
170 ret = true;
171 }
172 spin_unlock_irq(&task->sighand->siglock);
173
174 return ret;
175}
176
177static void ptrace_unfreeze_traced(struct task_struct *task)
178{
179 if (task->state != __TASK_TRACED)
180 return;
181
182 WARN_ON(!task->ptrace || task->parent != current);
183
184 /*
185 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
186 * Recheck state under the lock to close this race.
187 */
188 spin_lock_irq(&task->sighand->siglock);
189 if (task->state == __TASK_TRACED) {
190 if (__fatal_signal_pending(task))
191 wake_up_state(task, __TASK_TRACED);
192 else
193 task->state = TASK_TRACED;
194 }
195 spin_unlock_irq(&task->sighand->siglock);
196}
197
198/**
199 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
200 * @child: ptracee to check for
201 * @ignore_state: don't check whether @child is currently %TASK_TRACED
202 *
203 * Check whether @child is being ptraced by %current and ready for further
204 * ptrace operations. If @ignore_state is %false, @child also should be in
205 * %TASK_TRACED state and on return the child is guaranteed to be traced
206 * and not executing. If @ignore_state is %true, @child can be in any
207 * state.
208 *
209 * CONTEXT:
210 * Grabs and releases tasklist_lock and @child->sighand->siglock.
211 *
212 * RETURNS:
213 * 0 on success, -ESRCH if %child is not ready.
214 */
215static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
216{
217 int ret = -ESRCH;
218
219 /*
220 * We take the read lock around doing both checks to close a
221 * possible race where someone else was tracing our child and
222 * detached between these two checks. After this locked check,
223 * we are sure that this is our traced child and that can only
224 * be changed by us so it's not changing right after this.
225 */
226 read_lock(&tasklist_lock);
227 if (child->ptrace && child->parent == current) {
228 WARN_ON(child->state == __TASK_TRACED);
229 /*
230 * child->sighand can't be NULL, release_task()
231 * does ptrace_unlink() before __exit_signal().
232 */
233 if (ignore_state || ptrace_freeze_traced(child))
234 ret = 0;
235 }
236 read_unlock(&tasklist_lock);
237
238 if (!ret && !ignore_state) {
239 if (!wait_task_inactive(child, __TASK_TRACED)) {
240 /*
241 * This can only happen if may_ptrace_stop() fails and
242 * ptrace_stop() changes ->state back to TASK_RUNNING,
243 * so we should not worry about leaking __TASK_TRACED.
244 */
245 WARN_ON(child->state == __TASK_TRACED);
246 ret = -ESRCH;
247 }
248 }
249
250 return ret;
251}
252
253static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
254{
255 if (mode & PTRACE_MODE_NOAUDIT)
256 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
257 else
258 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
259}
260
261/* Returns 0 on success, -errno on denial. */
262static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
263{
264 const struct cred *cred = current_cred(), *tcred;
265 struct mm_struct *mm;
266 kuid_t caller_uid;
267 kgid_t caller_gid;
268
269 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
270 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
271 return -EPERM;
272 }
273
274 /* May we inspect the given task?
275 * This check is used both for attaching with ptrace
276 * and for allowing access to sensitive information in /proc.
277 *
278 * ptrace_attach denies several cases that /proc allows
279 * because setting up the necessary parent/child relationship
280 * or halting the specified task is impossible.
281 */
282
283 /* Don't let security modules deny introspection */
284 if (same_thread_group(task, current))
285 return 0;
286 rcu_read_lock();
287 if (mode & PTRACE_MODE_FSCREDS) {
288 caller_uid = cred->fsuid;
289 caller_gid = cred->fsgid;
290 } else {
291 /*
292 * Using the euid would make more sense here, but something
293 * in userland might rely on the old behavior, and this
294 * shouldn't be a security problem since
295 * PTRACE_MODE_REALCREDS implies that the caller explicitly
296 * used a syscall that requests access to another process
297 * (and not a filesystem syscall to procfs).
298 */
299 caller_uid = cred->uid;
300 caller_gid = cred->gid;
301 }
302 tcred = __task_cred(task);
303 if (uid_eq(caller_uid, tcred->euid) &&
304 uid_eq(caller_uid, tcred->suid) &&
305 uid_eq(caller_uid, tcred->uid) &&
306 gid_eq(caller_gid, tcred->egid) &&
307 gid_eq(caller_gid, tcred->sgid) &&
308 gid_eq(caller_gid, tcred->gid))
309 goto ok;
310 if (ptrace_has_cap(tcred->user_ns, mode))
311 goto ok;
312 rcu_read_unlock();
313 return -EPERM;
314ok:
315 rcu_read_unlock();
316 mm = task->mm;
317 if (mm &&
318 ((get_dumpable(mm) != SUID_DUMP_USER) &&
319 !ptrace_has_cap(mm->user_ns, mode)))
320 return -EPERM;
321
322 return security_ptrace_access_check(task, mode);
323}
324
325bool ptrace_may_access(struct task_struct *task, unsigned int mode)
326{
327 int err;
328 task_lock(task);
329 err = __ptrace_may_access(task, mode);
330 task_unlock(task);
331 return !err;
332}
333
334static int ptrace_attach(struct task_struct *task, long request,
335 unsigned long addr,
336 unsigned long flags)
337{
338 bool seize = (request == PTRACE_SEIZE);
339 int retval;
340
341 retval = -EIO;
342 if (seize) {
343 if (addr != 0)
344 goto out;
345 if (flags & ~(unsigned long)PTRACE_O_MASK)
346 goto out;
347 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
348 } else {
349 flags = PT_PTRACED;
350 }
351
352 audit_ptrace(task);
353
354 retval = -EPERM;
355 if (unlikely(task->flags & PF_KTHREAD))
356 goto out;
357 if (same_thread_group(task, current))
358 goto out;
359
360 /*
361 * Protect exec's credential calculations against our interference;
362 * SUID, SGID and LSM creds get determined differently
363 * under ptrace.
364 */
365 retval = -ERESTARTNOINTR;
366 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
367 goto out;
368
369 task_lock(task);
370 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
371 task_unlock(task);
372 if (retval)
373 goto unlock_creds;
374
375 write_lock_irq(&tasklist_lock);
376 retval = -EPERM;
377 if (unlikely(task->exit_state))
378 goto unlock_tasklist;
379 if (task->ptrace)
380 goto unlock_tasklist;
381
382 if (seize)
383 flags |= PT_SEIZED;
384 task->ptrace = flags;
385
386 __ptrace_link(task, current);
387
388 /* SEIZE doesn't trap tracee on attach */
389 if (!seize)
390 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
391
392 spin_lock(&task->sighand->siglock);
393
394 /*
395 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
396 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
397 * will be cleared if the child completes the transition or any
398 * event which clears the group stop states happens. We'll wait
399 * for the transition to complete before returning from this
400 * function.
401 *
402 * This hides STOPPED -> RUNNING -> TRACED transition from the
403 * attaching thread but a different thread in the same group can
404 * still observe the transient RUNNING state. IOW, if another
405 * thread's WNOHANG wait(2) on the stopped tracee races against
406 * ATTACH, the wait(2) may fail due to the transient RUNNING.
407 *
408 * The following task_is_stopped() test is safe as both transitions
409 * in and out of STOPPED are protected by siglock.
410 */
411 if (task_is_stopped(task) &&
412 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
413 signal_wake_up_state(task, __TASK_STOPPED);
414
415 spin_unlock(&task->sighand->siglock);
416
417 retval = 0;
418unlock_tasklist:
419 write_unlock_irq(&tasklist_lock);
420unlock_creds:
421 mutex_unlock(&task->signal->cred_guard_mutex);
422out:
423 if (!retval) {
424 /*
425 * We do not bother to change retval or clear JOBCTL_TRAPPING
426 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
427 * not return to user-mode, it will exit and clear this bit in
428 * __ptrace_unlink() if it wasn't already cleared by the tracee;
429 * and until then nobody can ptrace this task.
430 */
431 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
432 proc_ptrace_connector(task, PTRACE_ATTACH);
433 }
434
435 return retval;
436}
437
438/**
439 * ptrace_traceme -- helper for PTRACE_TRACEME
440 *
441 * Performs checks and sets PT_PTRACED.
442 * Should be used by all ptrace implementations for PTRACE_TRACEME.
443 */
444static int ptrace_traceme(void)
445{
446 int ret = -EPERM;
447
448 write_lock_irq(&tasklist_lock);
449 /* Are we already being traced? */
450 if (!current->ptrace) {
451 ret = security_ptrace_traceme(current->parent);
452 /*
453 * Check PF_EXITING to ensure ->real_parent has not passed
454 * exit_ptrace(). Otherwise we don't report the error but
455 * pretend ->real_parent untraces us right after return.
456 */
457 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
458 current->ptrace = PT_PTRACED;
459 __ptrace_link(current, current->real_parent);
460 }
461 }
462 write_unlock_irq(&tasklist_lock);
463
464 return ret;
465}
466
467/*
468 * Called with irqs disabled, returns true if childs should reap themselves.
469 */
470static int ignoring_children(struct sighand_struct *sigh)
471{
472 int ret;
473 spin_lock(&sigh->siglock);
474 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
475 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
476 spin_unlock(&sigh->siglock);
477 return ret;
478}
479
480/*
481 * Called with tasklist_lock held for writing.
482 * Unlink a traced task, and clean it up if it was a traced zombie.
483 * Return true if it needs to be reaped with release_task().
484 * (We can't call release_task() here because we already hold tasklist_lock.)
485 *
486 * If it's a zombie, our attachedness prevented normal parent notification
487 * or self-reaping. Do notification now if it would have happened earlier.
488 * If it should reap itself, return true.
489 *
490 * If it's our own child, there is no notification to do. But if our normal
491 * children self-reap, then this child was prevented by ptrace and we must
492 * reap it now, in that case we must also wake up sub-threads sleeping in
493 * do_wait().
494 */
495static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
496{
497 bool dead;
498
499 __ptrace_unlink(p);
500
501 if (p->exit_state != EXIT_ZOMBIE)
502 return false;
503
504 dead = !thread_group_leader(p);
505
506 if (!dead && thread_group_empty(p)) {
507 if (!same_thread_group(p->real_parent, tracer))
508 dead = do_notify_parent(p, p->exit_signal);
509 else if (ignoring_children(tracer->sighand)) {
510 __wake_up_parent(p, tracer);
511 dead = true;
512 }
513 }
514 /* Mark it as in the process of being reaped. */
515 if (dead)
516 p->exit_state = EXIT_DEAD;
517 return dead;
518}
519
520static int ptrace_detach(struct task_struct *child, unsigned int data)
521{
522 if (!valid_signal(data))
523 return -EIO;
524
525 /* Architecture-specific hardware disable .. */
526 ptrace_disable(child);
527
528 write_lock_irq(&tasklist_lock);
529 /*
530 * We rely on ptrace_freeze_traced(). It can't be killed and
531 * untraced by another thread, it can't be a zombie.
532 */
533 WARN_ON(!child->ptrace || child->exit_state);
534 /*
535 * tasklist_lock avoids the race with wait_task_stopped(), see
536 * the comment in ptrace_resume().
537 */
538 child->exit_code = data;
539 __ptrace_detach(current, child);
540 write_unlock_irq(&tasklist_lock);
541
542 proc_ptrace_connector(child, PTRACE_DETACH);
543
544 return 0;
545}
546
547/*
548 * Detach all tasks we were using ptrace on. Called with tasklist held
549 * for writing.
550 */
551void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
552{
553 struct task_struct *p, *n;
554
555 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
556 if (unlikely(p->ptrace & PT_EXITKILL))
557 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
558
559 if (__ptrace_detach(tracer, p))
560 list_add(&p->ptrace_entry, dead);
561 }
562}
563
564int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
565{
566 int copied = 0;
567
568 while (len > 0) {
569 char buf[128];
570 int this_len, retval;
571
572 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
573 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
574
575 if (!retval) {
576 if (copied)
577 break;
578 return -EIO;
579 }
580 if (copy_to_user(dst, buf, retval))
581 return -EFAULT;
582 copied += retval;
583 src += retval;
584 dst += retval;
585 len -= retval;
586 }
587 return copied;
588}
589
590int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
591{
592 int copied = 0;
593
594 while (len > 0) {
595 char buf[128];
596 int this_len, retval;
597
598 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
599 if (copy_from_user(buf, src, this_len))
600 return -EFAULT;
601 retval = ptrace_access_vm(tsk, dst, buf, this_len,
602 FOLL_FORCE | FOLL_WRITE);
603 if (!retval) {
604 if (copied)
605 break;
606 return -EIO;
607 }
608 copied += retval;
609 src += retval;
610 dst += retval;
611 len -= retval;
612 }
613 return copied;
614}
615
616static int ptrace_setoptions(struct task_struct *child, unsigned long data)
617{
618 unsigned flags;
619
620 if (data & ~(unsigned long)PTRACE_O_MASK)
621 return -EINVAL;
622
623 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
624 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
625 !IS_ENABLED(CONFIG_SECCOMP))
626 return -EINVAL;
627
628 if (!capable(CAP_SYS_ADMIN))
629 return -EPERM;
630
631 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
632 current->ptrace & PT_SUSPEND_SECCOMP)
633 return -EPERM;
634 }
635
636 /* Avoid intermediate state when all opts are cleared */
637 flags = child->ptrace;
638 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
639 flags |= (data << PT_OPT_FLAG_SHIFT);
640 child->ptrace = flags;
641
642 return 0;
643}
644
645static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
646{
647 unsigned long flags;
648 int error = -ESRCH;
649
650 if (lock_task_sighand(child, &flags)) {
651 error = -EINVAL;
652 if (likely(child->last_siginfo != NULL)) {
653 *info = *child->last_siginfo;
654 error = 0;
655 }
656 unlock_task_sighand(child, &flags);
657 }
658 return error;
659}
660
661static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
662{
663 unsigned long flags;
664 int error = -ESRCH;
665
666 if (lock_task_sighand(child, &flags)) {
667 error = -EINVAL;
668 if (likely(child->last_siginfo != NULL)) {
669 *child->last_siginfo = *info;
670 error = 0;
671 }
672 unlock_task_sighand(child, &flags);
673 }
674 return error;
675}
676
677static int ptrace_peek_siginfo(struct task_struct *child,
678 unsigned long addr,
679 unsigned long data)
680{
681 struct ptrace_peeksiginfo_args arg;
682 struct sigpending *pending;
683 struct sigqueue *q;
684 int ret, i;
685
686 ret = copy_from_user(&arg, (void __user *) addr,
687 sizeof(struct ptrace_peeksiginfo_args));
688 if (ret)
689 return -EFAULT;
690
691 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
692 return -EINVAL; /* unknown flags */
693
694 if (arg.nr < 0)
695 return -EINVAL;
696
697 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
698 pending = &child->signal->shared_pending;
699 else
700 pending = &child->pending;
701
702 for (i = 0; i < arg.nr; ) {
703 siginfo_t info;
704 s32 off = arg.off + i;
705
706 spin_lock_irq(&child->sighand->siglock);
707 list_for_each_entry(q, &pending->list, list) {
708 if (!off--) {
709 copy_siginfo(&info, &q->info);
710 break;
711 }
712 }
713 spin_unlock_irq(&child->sighand->siglock);
714
715 if (off >= 0) /* beyond the end of the list */
716 break;
717
718#ifdef CONFIG_COMPAT
719 if (unlikely(in_compat_syscall())) {
720 compat_siginfo_t __user *uinfo = compat_ptr(data);
721
722 if (copy_siginfo_to_user32(uinfo, &info) ||
723 __put_user(info.si_code, &uinfo->si_code)) {
724 ret = -EFAULT;
725 break;
726 }
727
728 } else
729#endif
730 {
731 siginfo_t __user *uinfo = (siginfo_t __user *) data;
732
733 if (copy_siginfo_to_user(uinfo, &info) ||
734 __put_user(info.si_code, &uinfo->si_code)) {
735 ret = -EFAULT;
736 break;
737 }
738 }
739
740 data += sizeof(siginfo_t);
741 i++;
742
743 if (signal_pending(current))
744 break;
745
746 cond_resched();
747 }
748
749 if (i > 0)
750 return i;
751
752 return ret;
753}
754
755#ifdef PTRACE_SINGLESTEP
756#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
757#else
758#define is_singlestep(request) 0
759#endif
760
761#ifdef PTRACE_SINGLEBLOCK
762#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
763#else
764#define is_singleblock(request) 0
765#endif
766
767#ifdef PTRACE_SYSEMU
768#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
769#else
770#define is_sysemu_singlestep(request) 0
771#endif
772
773static int ptrace_resume(struct task_struct *child, long request,
774 unsigned long data)
775{
776 bool need_siglock;
777
778 if (!valid_signal(data))
779 return -EIO;
780
781 if (request == PTRACE_SYSCALL)
782 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
783 else
784 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
785
786#ifdef TIF_SYSCALL_EMU
787 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
788 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
789 else
790 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
791#endif
792
793 if (is_singleblock(request)) {
794 if (unlikely(!arch_has_block_step()))
795 return -EIO;
796 user_enable_block_step(child);
797 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
798 if (unlikely(!arch_has_single_step()))
799 return -EIO;
800 user_enable_single_step(child);
801 } else {
802 user_disable_single_step(child);
803 }
804
805 /*
806 * Change ->exit_code and ->state under siglock to avoid the race
807 * with wait_task_stopped() in between; a non-zero ->exit_code will
808 * wrongly look like another report from tracee.
809 *
810 * Note that we need siglock even if ->exit_code == data and/or this
811 * status was not reported yet, the new status must not be cleared by
812 * wait_task_stopped() after resume.
813 *
814 * If data == 0 we do not care if wait_task_stopped() reports the old
815 * status and clears the code too; this can't race with the tracee, it
816 * takes siglock after resume.
817 */
818 need_siglock = data && !thread_group_empty(current);
819 if (need_siglock)
820 spin_lock_irq(&child->sighand->siglock);
821 child->exit_code = data;
822 wake_up_state(child, __TASK_TRACED);
823 if (need_siglock)
824 spin_unlock_irq(&child->sighand->siglock);
825
826 return 0;
827}
828
829#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
830
831static const struct user_regset *
832find_regset(const struct user_regset_view *view, unsigned int type)
833{
834 const struct user_regset *regset;
835 int n;
836
837 for (n = 0; n < view->n; ++n) {
838 regset = view->regsets + n;
839 if (regset->core_note_type == type)
840 return regset;
841 }
842
843 return NULL;
844}
845
846static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
847 struct iovec *kiov)
848{
849 const struct user_regset_view *view = task_user_regset_view(task);
850 const struct user_regset *regset = find_regset(view, type);
851 int regset_no;
852
853 if (!regset || (kiov->iov_len % regset->size) != 0)
854 return -EINVAL;
855
856 regset_no = regset - view->regsets;
857 kiov->iov_len = min(kiov->iov_len,
858 (__kernel_size_t) (regset->n * regset->size));
859
860 if (req == PTRACE_GETREGSET)
861 return copy_regset_to_user(task, view, regset_no, 0,
862 kiov->iov_len, kiov->iov_base);
863 else
864 return copy_regset_from_user(task, view, regset_no, 0,
865 kiov->iov_len, kiov->iov_base);
866}
867
868/*
869 * This is declared in linux/regset.h and defined in machine-dependent
870 * code. We put the export here, near the primary machine-neutral use,
871 * to ensure no machine forgets it.
872 */
873EXPORT_SYMBOL_GPL(task_user_regset_view);
874#endif
875
876int ptrace_request(struct task_struct *child, long request,
877 unsigned long addr, unsigned long data)
878{
879 bool seized = child->ptrace & PT_SEIZED;
880 int ret = -EIO;
881 siginfo_t siginfo, *si;
882 void __user *datavp = (void __user *) data;
883 unsigned long __user *datalp = datavp;
884 unsigned long flags;
885
886 switch (request) {
887 case PTRACE_PEEKTEXT:
888 case PTRACE_PEEKDATA:
889 return generic_ptrace_peekdata(child, addr, data);
890 case PTRACE_POKETEXT:
891 case PTRACE_POKEDATA:
892 return generic_ptrace_pokedata(child, addr, data);
893
894#ifdef PTRACE_OLDSETOPTIONS
895 case PTRACE_OLDSETOPTIONS:
896#endif
897 case PTRACE_SETOPTIONS:
898 ret = ptrace_setoptions(child, data);
899 break;
900 case PTRACE_GETEVENTMSG:
901 ret = put_user(child->ptrace_message, datalp);
902 break;
903
904 case PTRACE_PEEKSIGINFO:
905 ret = ptrace_peek_siginfo(child, addr, data);
906 break;
907
908 case PTRACE_GETSIGINFO:
909 ret = ptrace_getsiginfo(child, &siginfo);
910 if (!ret)
911 ret = copy_siginfo_to_user(datavp, &siginfo);
912 break;
913
914 case PTRACE_SETSIGINFO:
915 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
916 ret = -EFAULT;
917 else
918 ret = ptrace_setsiginfo(child, &siginfo);
919 break;
920
921 case PTRACE_GETSIGMASK:
922 if (addr != sizeof(sigset_t)) {
923 ret = -EINVAL;
924 break;
925 }
926
927 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
928 ret = -EFAULT;
929 else
930 ret = 0;
931
932 break;
933
934 case PTRACE_SETSIGMASK: {
935 sigset_t new_set;
936
937 if (addr != sizeof(sigset_t)) {
938 ret = -EINVAL;
939 break;
940 }
941
942 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
943 ret = -EFAULT;
944 break;
945 }
946
947 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
948
949 /*
950 * Every thread does recalc_sigpending() after resume, so
951 * retarget_shared_pending() and recalc_sigpending() are not
952 * called here.
953 */
954 spin_lock_irq(&child->sighand->siglock);
955 child->blocked = new_set;
956 spin_unlock_irq(&child->sighand->siglock);
957
958 ret = 0;
959 break;
960 }
961
962 case PTRACE_INTERRUPT:
963 /*
964 * Stop tracee without any side-effect on signal or job
965 * control. At least one trap is guaranteed to happen
966 * after this request. If @child is already trapped, the
967 * current trap is not disturbed and another trap will
968 * happen after the current trap is ended with PTRACE_CONT.
969 *
970 * The actual trap might not be PTRACE_EVENT_STOP trap but
971 * the pending condition is cleared regardless.
972 */
973 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
974 break;
975
976 /*
977 * INTERRUPT doesn't disturb existing trap sans one
978 * exception. If ptracer issued LISTEN for the current
979 * STOP, this INTERRUPT should clear LISTEN and re-trap
980 * tracee into STOP.
981 */
982 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
983 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
984
985 unlock_task_sighand(child, &flags);
986 ret = 0;
987 break;
988
989 case PTRACE_LISTEN:
990 /*
991 * Listen for events. Tracee must be in STOP. It's not
992 * resumed per-se but is not considered to be in TRACED by
993 * wait(2) or ptrace(2). If an async event (e.g. group
994 * stop state change) happens, tracee will enter STOP trap
995 * again. Alternatively, ptracer can issue INTERRUPT to
996 * finish listening and re-trap tracee into STOP.
997 */
998 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
999 break;
1000
1001 si = child->last_siginfo;
1002 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1003 child->jobctl |= JOBCTL_LISTENING;
1004 /*
1005 * If NOTIFY is set, it means event happened between
1006 * start of this trap and now. Trigger re-trap.
1007 */
1008 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1009 ptrace_signal_wake_up(child, true);
1010 ret = 0;
1011 }
1012 unlock_task_sighand(child, &flags);
1013 break;
1014
1015 case PTRACE_DETACH: /* detach a process that was attached. */
1016 ret = ptrace_detach(child, data);
1017 break;
1018
1019#ifdef CONFIG_BINFMT_ELF_FDPIC
1020 case PTRACE_GETFDPIC: {
1021 struct mm_struct *mm = get_task_mm(child);
1022 unsigned long tmp = 0;
1023
1024 ret = -ESRCH;
1025 if (!mm)
1026 break;
1027
1028 switch (addr) {
1029 case PTRACE_GETFDPIC_EXEC:
1030 tmp = mm->context.exec_fdpic_loadmap;
1031 break;
1032 case PTRACE_GETFDPIC_INTERP:
1033 tmp = mm->context.interp_fdpic_loadmap;
1034 break;
1035 default:
1036 break;
1037 }
1038 mmput(mm);
1039
1040 ret = put_user(tmp, datalp);
1041 break;
1042 }
1043#endif
1044
1045#ifdef PTRACE_SINGLESTEP
1046 case PTRACE_SINGLESTEP:
1047#endif
1048#ifdef PTRACE_SINGLEBLOCK
1049 case PTRACE_SINGLEBLOCK:
1050#endif
1051#ifdef PTRACE_SYSEMU
1052 case PTRACE_SYSEMU:
1053 case PTRACE_SYSEMU_SINGLESTEP:
1054#endif
1055 case PTRACE_SYSCALL:
1056 case PTRACE_CONT:
1057 return ptrace_resume(child, request, data);
1058
1059 case PTRACE_KILL:
1060 if (child->exit_state) /* already dead */
1061 return 0;
1062 return ptrace_resume(child, request, SIGKILL);
1063
1064#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1065 case PTRACE_GETREGSET:
1066 case PTRACE_SETREGSET: {
1067 struct iovec kiov;
1068 struct iovec __user *uiov = datavp;
1069
1070 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1071 return -EFAULT;
1072
1073 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1074 __get_user(kiov.iov_len, &uiov->iov_len))
1075 return -EFAULT;
1076
1077 ret = ptrace_regset(child, request, addr, &kiov);
1078 if (!ret)
1079 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1080 break;
1081 }
1082#endif
1083
1084 case PTRACE_SECCOMP_GET_FILTER:
1085 ret = seccomp_get_filter(child, addr, datavp);
1086 break;
1087
1088 default:
1089 break;
1090 }
1091
1092 return ret;
1093}
1094
1095static struct task_struct *ptrace_get_task_struct(pid_t pid)
1096{
1097 struct task_struct *child;
1098
1099 rcu_read_lock();
1100 child = find_task_by_vpid(pid);
1101 if (child)
1102 get_task_struct(child);
1103 rcu_read_unlock();
1104
1105 if (!child)
1106 return ERR_PTR(-ESRCH);
1107 return child;
1108}
1109
1110#ifndef arch_ptrace_attach
1111#define arch_ptrace_attach(child) do { } while (0)
1112#endif
1113
1114SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1115 unsigned long, data)
1116{
1117 struct task_struct *child;
1118 long ret;
1119
1120 if (request == PTRACE_TRACEME) {
1121 ret = ptrace_traceme();
1122 if (!ret)
1123 arch_ptrace_attach(current);
1124 goto out;
1125 }
1126
1127 child = ptrace_get_task_struct(pid);
1128 if (IS_ERR(child)) {
1129 ret = PTR_ERR(child);
1130 goto out;
1131 }
1132
1133 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1134 ret = ptrace_attach(child, request, addr, data);
1135 /*
1136 * Some architectures need to do book-keeping after
1137 * a ptrace attach.
1138 */
1139 if (!ret)
1140 arch_ptrace_attach(child);
1141 goto out_put_task_struct;
1142 }
1143
1144 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1145 request == PTRACE_INTERRUPT);
1146 if (ret < 0)
1147 goto out_put_task_struct;
1148
1149 ret = arch_ptrace(child, request, addr, data);
1150 if (ret || request != PTRACE_DETACH)
1151 ptrace_unfreeze_traced(child);
1152
1153 out_put_task_struct:
1154 put_task_struct(child);
1155 out:
1156 return ret;
1157}
1158
1159int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1160 unsigned long data)
1161{
1162 unsigned long tmp;
1163 int copied;
1164
1165 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1166 if (copied != sizeof(tmp))
1167 return -EIO;
1168 return put_user(tmp, (unsigned long __user *)data);
1169}
1170
1171int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1172 unsigned long data)
1173{
1174 int copied;
1175
1176 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1177 FOLL_FORCE | FOLL_WRITE);
1178 return (copied == sizeof(data)) ? 0 : -EIO;
1179}
1180
1181#if defined CONFIG_COMPAT
1182
1183int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1184 compat_ulong_t addr, compat_ulong_t data)
1185{
1186 compat_ulong_t __user *datap = compat_ptr(data);
1187 compat_ulong_t word;
1188 siginfo_t siginfo;
1189 int ret;
1190
1191 switch (request) {
1192 case PTRACE_PEEKTEXT:
1193 case PTRACE_PEEKDATA:
1194 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1195 FOLL_FORCE);
1196 if (ret != sizeof(word))
1197 ret = -EIO;
1198 else
1199 ret = put_user(word, datap);
1200 break;
1201
1202 case PTRACE_POKETEXT:
1203 case PTRACE_POKEDATA:
1204 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1205 FOLL_FORCE | FOLL_WRITE);
1206 ret = (ret != sizeof(data) ? -EIO : 0);
1207 break;
1208
1209 case PTRACE_GETEVENTMSG:
1210 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1211 break;
1212
1213 case PTRACE_GETSIGINFO:
1214 ret = ptrace_getsiginfo(child, &siginfo);
1215 if (!ret)
1216 ret = copy_siginfo_to_user32(
1217 (struct compat_siginfo __user *) datap,
1218 &siginfo);
1219 break;
1220
1221 case PTRACE_SETSIGINFO:
1222 memset(&siginfo, 0, sizeof siginfo);
1223 if (copy_siginfo_from_user32(
1224 &siginfo, (struct compat_siginfo __user *) datap))
1225 ret = -EFAULT;
1226 else
1227 ret = ptrace_setsiginfo(child, &siginfo);
1228 break;
1229#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1230 case PTRACE_GETREGSET:
1231 case PTRACE_SETREGSET:
1232 {
1233 struct iovec kiov;
1234 struct compat_iovec __user *uiov =
1235 (struct compat_iovec __user *) datap;
1236 compat_uptr_t ptr;
1237 compat_size_t len;
1238
1239 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1240 return -EFAULT;
1241
1242 if (__get_user(ptr, &uiov->iov_base) ||
1243 __get_user(len, &uiov->iov_len))
1244 return -EFAULT;
1245
1246 kiov.iov_base = compat_ptr(ptr);
1247 kiov.iov_len = len;
1248
1249 ret = ptrace_regset(child, request, addr, &kiov);
1250 if (!ret)
1251 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1252 break;
1253 }
1254#endif
1255
1256 default:
1257 ret = ptrace_request(child, request, addr, data);
1258 }
1259
1260 return ret;
1261}
1262
1263COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1264 compat_long_t, addr, compat_long_t, data)
1265{
1266 struct task_struct *child;
1267 long ret;
1268
1269 if (request == PTRACE_TRACEME) {
1270 ret = ptrace_traceme();
1271 goto out;
1272 }
1273
1274 child = ptrace_get_task_struct(pid);
1275 if (IS_ERR(child)) {
1276 ret = PTR_ERR(child);
1277 goto out;
1278 }
1279
1280 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1281 ret = ptrace_attach(child, request, addr, data);
1282 /*
1283 * Some architectures need to do book-keeping after
1284 * a ptrace attach.
1285 */
1286 if (!ret)
1287 arch_ptrace_attach(child);
1288 goto out_put_task_struct;
1289 }
1290
1291 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1292 request == PTRACE_INTERRUPT);
1293 if (!ret) {
1294 ret = compat_arch_ptrace(child, request, addr, data);
1295 if (ret || request != PTRACE_DETACH)
1296 ptrace_unfreeze_traced(child);
1297 }
1298
1299 out_put_task_struct:
1300 put_task_struct(child);
1301 out:
1302 return ret;
1303}
1304#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/export.h>
12#include <linux/sched.h>
13#include <linux/sched/mm.h>
14#include <linux/sched/coredump.h>
15#include <linux/sched/task.h>
16#include <linux/errno.h>
17#include <linux/mm.h>
18#include <linux/highmem.h>
19#include <linux/pagemap.h>
20#include <linux/ptrace.h>
21#include <linux/security.h>
22#include <linux/signal.h>
23#include <linux/uio.h>
24#include <linux/audit.h>
25#include <linux/pid_namespace.h>
26#include <linux/syscalls.h>
27#include <linux/uaccess.h>
28#include <linux/regset.h>
29#include <linux/hw_breakpoint.h>
30#include <linux/cn_proc.h>
31#include <linux/compat.h>
32
33/*
34 * Access another process' address space via ptrace.
35 * Source/target buffer must be kernel space,
36 * Do not walk the page table directly, use get_user_pages
37 */
38int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
39 void *buf, int len, unsigned int gup_flags)
40{
41 struct mm_struct *mm;
42 int ret;
43
44 mm = get_task_mm(tsk);
45 if (!mm)
46 return 0;
47
48 if (!tsk->ptrace ||
49 (current != tsk->parent) ||
50 ((get_dumpable(mm) != SUID_DUMP_USER) &&
51 !ptracer_capable(tsk, mm->user_ns))) {
52 mmput(mm);
53 return 0;
54 }
55
56 ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
57 mmput(mm);
58
59 return ret;
60}
61
62
63void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
64 const struct cred *ptracer_cred)
65{
66 BUG_ON(!list_empty(&child->ptrace_entry));
67 list_add(&child->ptrace_entry, &new_parent->ptraced);
68 child->parent = new_parent;
69 child->ptracer_cred = get_cred(ptracer_cred);
70}
71
72/*
73 * ptrace a task: make the debugger its new parent and
74 * move it to the ptrace list.
75 *
76 * Must be called with the tasklist lock write-held.
77 */
78static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
79{
80 rcu_read_lock();
81 __ptrace_link(child, new_parent, __task_cred(new_parent));
82 rcu_read_unlock();
83}
84
85/**
86 * __ptrace_unlink - unlink ptracee and restore its execution state
87 * @child: ptracee to be unlinked
88 *
89 * Remove @child from the ptrace list, move it back to the original parent,
90 * and restore the execution state so that it conforms to the group stop
91 * state.
92 *
93 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
94 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
95 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
96 * If the ptracer is exiting, the ptracee can be in any state.
97 *
98 * After detach, the ptracee should be in a state which conforms to the
99 * group stop. If the group is stopped or in the process of stopping, the
100 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
101 * up from TASK_TRACED.
102 *
103 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
104 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
105 * to but in the opposite direction of what happens while attaching to a
106 * stopped task. However, in this direction, the intermediate RUNNING
107 * state is not hidden even from the current ptracer and if it immediately
108 * re-attaches and performs a WNOHANG wait(2), it may fail.
109 *
110 * CONTEXT:
111 * write_lock_irq(tasklist_lock)
112 */
113void __ptrace_unlink(struct task_struct *child)
114{
115 const struct cred *old_cred;
116 BUG_ON(!child->ptrace);
117
118 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
119
120 child->parent = child->real_parent;
121 list_del_init(&child->ptrace_entry);
122 old_cred = child->ptracer_cred;
123 child->ptracer_cred = NULL;
124 put_cred(old_cred);
125
126 spin_lock(&child->sighand->siglock);
127 child->ptrace = 0;
128 /*
129 * Clear all pending traps and TRAPPING. TRAPPING should be
130 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
131 */
132 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
133 task_clear_jobctl_trapping(child);
134
135 /*
136 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
137 * @child isn't dead.
138 */
139 if (!(child->flags & PF_EXITING) &&
140 (child->signal->flags & SIGNAL_STOP_STOPPED ||
141 child->signal->group_stop_count)) {
142 child->jobctl |= JOBCTL_STOP_PENDING;
143
144 /*
145 * This is only possible if this thread was cloned by the
146 * traced task running in the stopped group, set the signal
147 * for the future reports.
148 * FIXME: we should change ptrace_init_task() to handle this
149 * case.
150 */
151 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
152 child->jobctl |= SIGSTOP;
153 }
154
155 /*
156 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
157 * @child in the butt. Note that @resume should be used iff @child
158 * is in TASK_TRACED; otherwise, we might unduly disrupt
159 * TASK_KILLABLE sleeps.
160 */
161 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
162 ptrace_signal_wake_up(child, true);
163
164 spin_unlock(&child->sighand->siglock);
165}
166
167/* Ensure that nothing can wake it up, even SIGKILL */
168static bool ptrace_freeze_traced(struct task_struct *task)
169{
170 bool ret = false;
171
172 /* Lockless, nobody but us can set this flag */
173 if (task->jobctl & JOBCTL_LISTENING)
174 return ret;
175
176 spin_lock_irq(&task->sighand->siglock);
177 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
178 task->state = __TASK_TRACED;
179 ret = true;
180 }
181 spin_unlock_irq(&task->sighand->siglock);
182
183 return ret;
184}
185
186static void ptrace_unfreeze_traced(struct task_struct *task)
187{
188 if (task->state != __TASK_TRACED)
189 return;
190
191 WARN_ON(!task->ptrace || task->parent != current);
192
193 /*
194 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
195 * Recheck state under the lock to close this race.
196 */
197 spin_lock_irq(&task->sighand->siglock);
198 if (task->state == __TASK_TRACED) {
199 if (__fatal_signal_pending(task))
200 wake_up_state(task, __TASK_TRACED);
201 else
202 task->state = TASK_TRACED;
203 }
204 spin_unlock_irq(&task->sighand->siglock);
205}
206
207/**
208 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
209 * @child: ptracee to check for
210 * @ignore_state: don't check whether @child is currently %TASK_TRACED
211 *
212 * Check whether @child is being ptraced by %current and ready for further
213 * ptrace operations. If @ignore_state is %false, @child also should be in
214 * %TASK_TRACED state and on return the child is guaranteed to be traced
215 * and not executing. If @ignore_state is %true, @child can be in any
216 * state.
217 *
218 * CONTEXT:
219 * Grabs and releases tasklist_lock and @child->sighand->siglock.
220 *
221 * RETURNS:
222 * 0 on success, -ESRCH if %child is not ready.
223 */
224static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
225{
226 int ret = -ESRCH;
227
228 /*
229 * We take the read lock around doing both checks to close a
230 * possible race where someone else was tracing our child and
231 * detached between these two checks. After this locked check,
232 * we are sure that this is our traced child and that can only
233 * be changed by us so it's not changing right after this.
234 */
235 read_lock(&tasklist_lock);
236 if (child->ptrace && child->parent == current) {
237 WARN_ON(child->state == __TASK_TRACED);
238 /*
239 * child->sighand can't be NULL, release_task()
240 * does ptrace_unlink() before __exit_signal().
241 */
242 if (ignore_state || ptrace_freeze_traced(child))
243 ret = 0;
244 }
245 read_unlock(&tasklist_lock);
246
247 if (!ret && !ignore_state) {
248 if (!wait_task_inactive(child, __TASK_TRACED)) {
249 /*
250 * This can only happen if may_ptrace_stop() fails and
251 * ptrace_stop() changes ->state back to TASK_RUNNING,
252 * so we should not worry about leaking __TASK_TRACED.
253 */
254 WARN_ON(child->state == __TASK_TRACED);
255 ret = -ESRCH;
256 }
257 }
258
259 return ret;
260}
261
262static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
263{
264 if (mode & PTRACE_MODE_NOAUDIT)
265 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
266 else
267 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
268}
269
270/* Returns 0 on success, -errno on denial. */
271static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
272{
273 const struct cred *cred = current_cred(), *tcred;
274 struct mm_struct *mm;
275 kuid_t caller_uid;
276 kgid_t caller_gid;
277
278 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
279 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
280 return -EPERM;
281 }
282
283 /* May we inspect the given task?
284 * This check is used both for attaching with ptrace
285 * and for allowing access to sensitive information in /proc.
286 *
287 * ptrace_attach denies several cases that /proc allows
288 * because setting up the necessary parent/child relationship
289 * or halting the specified task is impossible.
290 */
291
292 /* Don't let security modules deny introspection */
293 if (same_thread_group(task, current))
294 return 0;
295 rcu_read_lock();
296 if (mode & PTRACE_MODE_FSCREDS) {
297 caller_uid = cred->fsuid;
298 caller_gid = cred->fsgid;
299 } else {
300 /*
301 * Using the euid would make more sense here, but something
302 * in userland might rely on the old behavior, and this
303 * shouldn't be a security problem since
304 * PTRACE_MODE_REALCREDS implies that the caller explicitly
305 * used a syscall that requests access to another process
306 * (and not a filesystem syscall to procfs).
307 */
308 caller_uid = cred->uid;
309 caller_gid = cred->gid;
310 }
311 tcred = __task_cred(task);
312 if (uid_eq(caller_uid, tcred->euid) &&
313 uid_eq(caller_uid, tcred->suid) &&
314 uid_eq(caller_uid, tcred->uid) &&
315 gid_eq(caller_gid, tcred->egid) &&
316 gid_eq(caller_gid, tcred->sgid) &&
317 gid_eq(caller_gid, tcred->gid))
318 goto ok;
319 if (ptrace_has_cap(tcred->user_ns, mode))
320 goto ok;
321 rcu_read_unlock();
322 return -EPERM;
323ok:
324 rcu_read_unlock();
325 mm = task->mm;
326 if (mm &&
327 ((get_dumpable(mm) != SUID_DUMP_USER) &&
328 !ptrace_has_cap(mm->user_ns, mode)))
329 return -EPERM;
330
331 return security_ptrace_access_check(task, mode);
332}
333
334bool ptrace_may_access(struct task_struct *task, unsigned int mode)
335{
336 int err;
337 task_lock(task);
338 err = __ptrace_may_access(task, mode);
339 task_unlock(task);
340 return !err;
341}
342
343static int ptrace_attach(struct task_struct *task, long request,
344 unsigned long addr,
345 unsigned long flags)
346{
347 bool seize = (request == PTRACE_SEIZE);
348 int retval;
349
350 retval = -EIO;
351 if (seize) {
352 if (addr != 0)
353 goto out;
354 if (flags & ~(unsigned long)PTRACE_O_MASK)
355 goto out;
356 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
357 } else {
358 flags = PT_PTRACED;
359 }
360
361 audit_ptrace(task);
362
363 retval = -EPERM;
364 if (unlikely(task->flags & PF_KTHREAD))
365 goto out;
366 if (same_thread_group(task, current))
367 goto out;
368
369 /*
370 * Protect exec's credential calculations against our interference;
371 * SUID, SGID and LSM creds get determined differently
372 * under ptrace.
373 */
374 retval = -ERESTARTNOINTR;
375 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
376 goto out;
377
378 task_lock(task);
379 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
380 task_unlock(task);
381 if (retval)
382 goto unlock_creds;
383
384 write_lock_irq(&tasklist_lock);
385 retval = -EPERM;
386 if (unlikely(task->exit_state))
387 goto unlock_tasklist;
388 if (task->ptrace)
389 goto unlock_tasklist;
390
391 if (seize)
392 flags |= PT_SEIZED;
393 task->ptrace = flags;
394
395 ptrace_link(task, current);
396
397 /* SEIZE doesn't trap tracee on attach */
398 if (!seize)
399 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
400
401 spin_lock(&task->sighand->siglock);
402
403 /*
404 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
405 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
406 * will be cleared if the child completes the transition or any
407 * event which clears the group stop states happens. We'll wait
408 * for the transition to complete before returning from this
409 * function.
410 *
411 * This hides STOPPED -> RUNNING -> TRACED transition from the
412 * attaching thread but a different thread in the same group can
413 * still observe the transient RUNNING state. IOW, if another
414 * thread's WNOHANG wait(2) on the stopped tracee races against
415 * ATTACH, the wait(2) may fail due to the transient RUNNING.
416 *
417 * The following task_is_stopped() test is safe as both transitions
418 * in and out of STOPPED are protected by siglock.
419 */
420 if (task_is_stopped(task) &&
421 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
422 signal_wake_up_state(task, __TASK_STOPPED);
423
424 spin_unlock(&task->sighand->siglock);
425
426 retval = 0;
427unlock_tasklist:
428 write_unlock_irq(&tasklist_lock);
429unlock_creds:
430 mutex_unlock(&task->signal->cred_guard_mutex);
431out:
432 if (!retval) {
433 /*
434 * We do not bother to change retval or clear JOBCTL_TRAPPING
435 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
436 * not return to user-mode, it will exit and clear this bit in
437 * __ptrace_unlink() if it wasn't already cleared by the tracee;
438 * and until then nobody can ptrace this task.
439 */
440 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
441 proc_ptrace_connector(task, PTRACE_ATTACH);
442 }
443
444 return retval;
445}
446
447/**
448 * ptrace_traceme -- helper for PTRACE_TRACEME
449 *
450 * Performs checks and sets PT_PTRACED.
451 * Should be used by all ptrace implementations for PTRACE_TRACEME.
452 */
453static int ptrace_traceme(void)
454{
455 int ret = -EPERM;
456
457 write_lock_irq(&tasklist_lock);
458 /* Are we already being traced? */
459 if (!current->ptrace) {
460 ret = security_ptrace_traceme(current->parent);
461 /*
462 * Check PF_EXITING to ensure ->real_parent has not passed
463 * exit_ptrace(). Otherwise we don't report the error but
464 * pretend ->real_parent untraces us right after return.
465 */
466 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
467 current->ptrace = PT_PTRACED;
468 ptrace_link(current, current->real_parent);
469 }
470 }
471 write_unlock_irq(&tasklist_lock);
472
473 return ret;
474}
475
476/*
477 * Called with irqs disabled, returns true if childs should reap themselves.
478 */
479static int ignoring_children(struct sighand_struct *sigh)
480{
481 int ret;
482 spin_lock(&sigh->siglock);
483 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
484 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
485 spin_unlock(&sigh->siglock);
486 return ret;
487}
488
489/*
490 * Called with tasklist_lock held for writing.
491 * Unlink a traced task, and clean it up if it was a traced zombie.
492 * Return true if it needs to be reaped with release_task().
493 * (We can't call release_task() here because we already hold tasklist_lock.)
494 *
495 * If it's a zombie, our attachedness prevented normal parent notification
496 * or self-reaping. Do notification now if it would have happened earlier.
497 * If it should reap itself, return true.
498 *
499 * If it's our own child, there is no notification to do. But if our normal
500 * children self-reap, then this child was prevented by ptrace and we must
501 * reap it now, in that case we must also wake up sub-threads sleeping in
502 * do_wait().
503 */
504static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
505{
506 bool dead;
507
508 __ptrace_unlink(p);
509
510 if (p->exit_state != EXIT_ZOMBIE)
511 return false;
512
513 dead = !thread_group_leader(p);
514
515 if (!dead && thread_group_empty(p)) {
516 if (!same_thread_group(p->real_parent, tracer))
517 dead = do_notify_parent(p, p->exit_signal);
518 else if (ignoring_children(tracer->sighand)) {
519 __wake_up_parent(p, tracer);
520 dead = true;
521 }
522 }
523 /* Mark it as in the process of being reaped. */
524 if (dead)
525 p->exit_state = EXIT_DEAD;
526 return dead;
527}
528
529static int ptrace_detach(struct task_struct *child, unsigned int data)
530{
531 if (!valid_signal(data))
532 return -EIO;
533
534 /* Architecture-specific hardware disable .. */
535 ptrace_disable(child);
536
537 write_lock_irq(&tasklist_lock);
538 /*
539 * We rely on ptrace_freeze_traced(). It can't be killed and
540 * untraced by another thread, it can't be a zombie.
541 */
542 WARN_ON(!child->ptrace || child->exit_state);
543 /*
544 * tasklist_lock avoids the race with wait_task_stopped(), see
545 * the comment in ptrace_resume().
546 */
547 child->exit_code = data;
548 __ptrace_detach(current, child);
549 write_unlock_irq(&tasklist_lock);
550
551 proc_ptrace_connector(child, PTRACE_DETACH);
552
553 return 0;
554}
555
556/*
557 * Detach all tasks we were using ptrace on. Called with tasklist held
558 * for writing.
559 */
560void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
561{
562 struct task_struct *p, *n;
563
564 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
565 if (unlikely(p->ptrace & PT_EXITKILL))
566 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
567
568 if (__ptrace_detach(tracer, p))
569 list_add(&p->ptrace_entry, dead);
570 }
571}
572
573int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
574{
575 int copied = 0;
576
577 while (len > 0) {
578 char buf[128];
579 int this_len, retval;
580
581 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
582 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
583
584 if (!retval) {
585 if (copied)
586 break;
587 return -EIO;
588 }
589 if (copy_to_user(dst, buf, retval))
590 return -EFAULT;
591 copied += retval;
592 src += retval;
593 dst += retval;
594 len -= retval;
595 }
596 return copied;
597}
598
599int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
600{
601 int copied = 0;
602
603 while (len > 0) {
604 char buf[128];
605 int this_len, retval;
606
607 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
608 if (copy_from_user(buf, src, this_len))
609 return -EFAULT;
610 retval = ptrace_access_vm(tsk, dst, buf, this_len,
611 FOLL_FORCE | FOLL_WRITE);
612 if (!retval) {
613 if (copied)
614 break;
615 return -EIO;
616 }
617 copied += retval;
618 src += retval;
619 dst += retval;
620 len -= retval;
621 }
622 return copied;
623}
624
625static int ptrace_setoptions(struct task_struct *child, unsigned long data)
626{
627 unsigned flags;
628
629 if (data & ~(unsigned long)PTRACE_O_MASK)
630 return -EINVAL;
631
632 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
633 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
634 !IS_ENABLED(CONFIG_SECCOMP))
635 return -EINVAL;
636
637 if (!capable(CAP_SYS_ADMIN))
638 return -EPERM;
639
640 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
641 current->ptrace & PT_SUSPEND_SECCOMP)
642 return -EPERM;
643 }
644
645 /* Avoid intermediate state when all opts are cleared */
646 flags = child->ptrace;
647 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
648 flags |= (data << PT_OPT_FLAG_SHIFT);
649 child->ptrace = flags;
650
651 return 0;
652}
653
654static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
655{
656 unsigned long flags;
657 int error = -ESRCH;
658
659 if (lock_task_sighand(child, &flags)) {
660 error = -EINVAL;
661 if (likely(child->last_siginfo != NULL)) {
662 copy_siginfo(info, child->last_siginfo);
663 error = 0;
664 }
665 unlock_task_sighand(child, &flags);
666 }
667 return error;
668}
669
670static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
671{
672 unsigned long flags;
673 int error = -ESRCH;
674
675 if (lock_task_sighand(child, &flags)) {
676 error = -EINVAL;
677 if (likely(child->last_siginfo != NULL)) {
678 copy_siginfo(child->last_siginfo, info);
679 error = 0;
680 }
681 unlock_task_sighand(child, &flags);
682 }
683 return error;
684}
685
686static int ptrace_peek_siginfo(struct task_struct *child,
687 unsigned long addr,
688 unsigned long data)
689{
690 struct ptrace_peeksiginfo_args arg;
691 struct sigpending *pending;
692 struct sigqueue *q;
693 int ret, i;
694
695 ret = copy_from_user(&arg, (void __user *) addr,
696 sizeof(struct ptrace_peeksiginfo_args));
697 if (ret)
698 return -EFAULT;
699
700 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
701 return -EINVAL; /* unknown flags */
702
703 if (arg.nr < 0)
704 return -EINVAL;
705
706 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
707 pending = &child->signal->shared_pending;
708 else
709 pending = &child->pending;
710
711 for (i = 0; i < arg.nr; ) {
712 siginfo_t info;
713 s32 off = arg.off + i;
714
715 spin_lock_irq(&child->sighand->siglock);
716 list_for_each_entry(q, &pending->list, list) {
717 if (!off--) {
718 copy_siginfo(&info, &q->info);
719 break;
720 }
721 }
722 spin_unlock_irq(&child->sighand->siglock);
723
724 if (off >= 0) /* beyond the end of the list */
725 break;
726
727#ifdef CONFIG_COMPAT
728 if (unlikely(in_compat_syscall())) {
729 compat_siginfo_t __user *uinfo = compat_ptr(data);
730
731 if (copy_siginfo_to_user32(uinfo, &info)) {
732 ret = -EFAULT;
733 break;
734 }
735
736 } else
737#endif
738 {
739 siginfo_t __user *uinfo = (siginfo_t __user *) data;
740
741 if (copy_siginfo_to_user(uinfo, &info)) {
742 ret = -EFAULT;
743 break;
744 }
745 }
746
747 data += sizeof(siginfo_t);
748 i++;
749
750 if (signal_pending(current))
751 break;
752
753 cond_resched();
754 }
755
756 if (i > 0)
757 return i;
758
759 return ret;
760}
761
762#ifdef PTRACE_SINGLESTEP
763#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
764#else
765#define is_singlestep(request) 0
766#endif
767
768#ifdef PTRACE_SINGLEBLOCK
769#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
770#else
771#define is_singleblock(request) 0
772#endif
773
774#ifdef PTRACE_SYSEMU
775#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
776#else
777#define is_sysemu_singlestep(request) 0
778#endif
779
780static int ptrace_resume(struct task_struct *child, long request,
781 unsigned long data)
782{
783 bool need_siglock;
784
785 if (!valid_signal(data))
786 return -EIO;
787
788 if (request == PTRACE_SYSCALL)
789 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
790 else
791 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
792
793#ifdef TIF_SYSCALL_EMU
794 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
795 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
796 else
797 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
798#endif
799
800 if (is_singleblock(request)) {
801 if (unlikely(!arch_has_block_step()))
802 return -EIO;
803 user_enable_block_step(child);
804 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
805 if (unlikely(!arch_has_single_step()))
806 return -EIO;
807 user_enable_single_step(child);
808 } else {
809 user_disable_single_step(child);
810 }
811
812 /*
813 * Change ->exit_code and ->state under siglock to avoid the race
814 * with wait_task_stopped() in between; a non-zero ->exit_code will
815 * wrongly look like another report from tracee.
816 *
817 * Note that we need siglock even if ->exit_code == data and/or this
818 * status was not reported yet, the new status must not be cleared by
819 * wait_task_stopped() after resume.
820 *
821 * If data == 0 we do not care if wait_task_stopped() reports the old
822 * status and clears the code too; this can't race with the tracee, it
823 * takes siglock after resume.
824 */
825 need_siglock = data && !thread_group_empty(current);
826 if (need_siglock)
827 spin_lock_irq(&child->sighand->siglock);
828 child->exit_code = data;
829 wake_up_state(child, __TASK_TRACED);
830 if (need_siglock)
831 spin_unlock_irq(&child->sighand->siglock);
832
833 return 0;
834}
835
836#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
837
838static const struct user_regset *
839find_regset(const struct user_regset_view *view, unsigned int type)
840{
841 const struct user_regset *regset;
842 int n;
843
844 for (n = 0; n < view->n; ++n) {
845 regset = view->regsets + n;
846 if (regset->core_note_type == type)
847 return regset;
848 }
849
850 return NULL;
851}
852
853static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
854 struct iovec *kiov)
855{
856 const struct user_regset_view *view = task_user_regset_view(task);
857 const struct user_regset *regset = find_regset(view, type);
858 int regset_no;
859
860 if (!regset || (kiov->iov_len % regset->size) != 0)
861 return -EINVAL;
862
863 regset_no = regset - view->regsets;
864 kiov->iov_len = min(kiov->iov_len,
865 (__kernel_size_t) (regset->n * regset->size));
866
867 if (req == PTRACE_GETREGSET)
868 return copy_regset_to_user(task, view, regset_no, 0,
869 kiov->iov_len, kiov->iov_base);
870 else
871 return copy_regset_from_user(task, view, regset_no, 0,
872 kiov->iov_len, kiov->iov_base);
873}
874
875/*
876 * This is declared in linux/regset.h and defined in machine-dependent
877 * code. We put the export here, near the primary machine-neutral use,
878 * to ensure no machine forgets it.
879 */
880EXPORT_SYMBOL_GPL(task_user_regset_view);
881#endif
882
883int ptrace_request(struct task_struct *child, long request,
884 unsigned long addr, unsigned long data)
885{
886 bool seized = child->ptrace & PT_SEIZED;
887 int ret = -EIO;
888 siginfo_t siginfo, *si;
889 void __user *datavp = (void __user *) data;
890 unsigned long __user *datalp = datavp;
891 unsigned long flags;
892
893 switch (request) {
894 case PTRACE_PEEKTEXT:
895 case PTRACE_PEEKDATA:
896 return generic_ptrace_peekdata(child, addr, data);
897 case PTRACE_POKETEXT:
898 case PTRACE_POKEDATA:
899 return generic_ptrace_pokedata(child, addr, data);
900
901#ifdef PTRACE_OLDSETOPTIONS
902 case PTRACE_OLDSETOPTIONS:
903#endif
904 case PTRACE_SETOPTIONS:
905 ret = ptrace_setoptions(child, data);
906 break;
907 case PTRACE_GETEVENTMSG:
908 ret = put_user(child->ptrace_message, datalp);
909 break;
910
911 case PTRACE_PEEKSIGINFO:
912 ret = ptrace_peek_siginfo(child, addr, data);
913 break;
914
915 case PTRACE_GETSIGINFO:
916 ret = ptrace_getsiginfo(child, &siginfo);
917 if (!ret)
918 ret = copy_siginfo_to_user(datavp, &siginfo);
919 break;
920
921 case PTRACE_SETSIGINFO:
922 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
923 ret = -EFAULT;
924 else
925 ret = ptrace_setsiginfo(child, &siginfo);
926 break;
927
928 case PTRACE_GETSIGMASK:
929 if (addr != sizeof(sigset_t)) {
930 ret = -EINVAL;
931 break;
932 }
933
934 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
935 ret = -EFAULT;
936 else
937 ret = 0;
938
939 break;
940
941 case PTRACE_SETSIGMASK: {
942 sigset_t new_set;
943
944 if (addr != sizeof(sigset_t)) {
945 ret = -EINVAL;
946 break;
947 }
948
949 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
950 ret = -EFAULT;
951 break;
952 }
953
954 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
955
956 /*
957 * Every thread does recalc_sigpending() after resume, so
958 * retarget_shared_pending() and recalc_sigpending() are not
959 * called here.
960 */
961 spin_lock_irq(&child->sighand->siglock);
962 child->blocked = new_set;
963 spin_unlock_irq(&child->sighand->siglock);
964
965 ret = 0;
966 break;
967 }
968
969 case PTRACE_INTERRUPT:
970 /*
971 * Stop tracee without any side-effect on signal or job
972 * control. At least one trap is guaranteed to happen
973 * after this request. If @child is already trapped, the
974 * current trap is not disturbed and another trap will
975 * happen after the current trap is ended with PTRACE_CONT.
976 *
977 * The actual trap might not be PTRACE_EVENT_STOP trap but
978 * the pending condition is cleared regardless.
979 */
980 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
981 break;
982
983 /*
984 * INTERRUPT doesn't disturb existing trap sans one
985 * exception. If ptracer issued LISTEN for the current
986 * STOP, this INTERRUPT should clear LISTEN and re-trap
987 * tracee into STOP.
988 */
989 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
990 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
991
992 unlock_task_sighand(child, &flags);
993 ret = 0;
994 break;
995
996 case PTRACE_LISTEN:
997 /*
998 * Listen for events. Tracee must be in STOP. It's not
999 * resumed per-se but is not considered to be in TRACED by
1000 * wait(2) or ptrace(2). If an async event (e.g. group
1001 * stop state change) happens, tracee will enter STOP trap
1002 * again. Alternatively, ptracer can issue INTERRUPT to
1003 * finish listening and re-trap tracee into STOP.
1004 */
1005 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1006 break;
1007
1008 si = child->last_siginfo;
1009 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1010 child->jobctl |= JOBCTL_LISTENING;
1011 /*
1012 * If NOTIFY is set, it means event happened between
1013 * start of this trap and now. Trigger re-trap.
1014 */
1015 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1016 ptrace_signal_wake_up(child, true);
1017 ret = 0;
1018 }
1019 unlock_task_sighand(child, &flags);
1020 break;
1021
1022 case PTRACE_DETACH: /* detach a process that was attached. */
1023 ret = ptrace_detach(child, data);
1024 break;
1025
1026#ifdef CONFIG_BINFMT_ELF_FDPIC
1027 case PTRACE_GETFDPIC: {
1028 struct mm_struct *mm = get_task_mm(child);
1029 unsigned long tmp = 0;
1030
1031 ret = -ESRCH;
1032 if (!mm)
1033 break;
1034
1035 switch (addr) {
1036 case PTRACE_GETFDPIC_EXEC:
1037 tmp = mm->context.exec_fdpic_loadmap;
1038 break;
1039 case PTRACE_GETFDPIC_INTERP:
1040 tmp = mm->context.interp_fdpic_loadmap;
1041 break;
1042 default:
1043 break;
1044 }
1045 mmput(mm);
1046
1047 ret = put_user(tmp, datalp);
1048 break;
1049 }
1050#endif
1051
1052#ifdef PTRACE_SINGLESTEP
1053 case PTRACE_SINGLESTEP:
1054#endif
1055#ifdef PTRACE_SINGLEBLOCK
1056 case PTRACE_SINGLEBLOCK:
1057#endif
1058#ifdef PTRACE_SYSEMU
1059 case PTRACE_SYSEMU:
1060 case PTRACE_SYSEMU_SINGLESTEP:
1061#endif
1062 case PTRACE_SYSCALL:
1063 case PTRACE_CONT:
1064 return ptrace_resume(child, request, data);
1065
1066 case PTRACE_KILL:
1067 if (child->exit_state) /* already dead */
1068 return 0;
1069 return ptrace_resume(child, request, SIGKILL);
1070
1071#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1072 case PTRACE_GETREGSET:
1073 case PTRACE_SETREGSET: {
1074 struct iovec kiov;
1075 struct iovec __user *uiov = datavp;
1076
1077 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1078 return -EFAULT;
1079
1080 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1081 __get_user(kiov.iov_len, &uiov->iov_len))
1082 return -EFAULT;
1083
1084 ret = ptrace_regset(child, request, addr, &kiov);
1085 if (!ret)
1086 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1087 break;
1088 }
1089#endif
1090
1091 case PTRACE_SECCOMP_GET_FILTER:
1092 ret = seccomp_get_filter(child, addr, datavp);
1093 break;
1094
1095 case PTRACE_SECCOMP_GET_METADATA:
1096 ret = seccomp_get_metadata(child, addr, datavp);
1097 break;
1098
1099 default:
1100 break;
1101 }
1102
1103 return ret;
1104}
1105
1106#ifndef arch_ptrace_attach
1107#define arch_ptrace_attach(child) do { } while (0)
1108#endif
1109
1110SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1111 unsigned long, data)
1112{
1113 struct task_struct *child;
1114 long ret;
1115
1116 if (request == PTRACE_TRACEME) {
1117 ret = ptrace_traceme();
1118 if (!ret)
1119 arch_ptrace_attach(current);
1120 goto out;
1121 }
1122
1123 child = find_get_task_by_vpid(pid);
1124 if (!child) {
1125 ret = -ESRCH;
1126 goto out;
1127 }
1128
1129 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1130 ret = ptrace_attach(child, request, addr, data);
1131 /*
1132 * Some architectures need to do book-keeping after
1133 * a ptrace attach.
1134 */
1135 if (!ret)
1136 arch_ptrace_attach(child);
1137 goto out_put_task_struct;
1138 }
1139
1140 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1141 request == PTRACE_INTERRUPT);
1142 if (ret < 0)
1143 goto out_put_task_struct;
1144
1145 ret = arch_ptrace(child, request, addr, data);
1146 if (ret || request != PTRACE_DETACH)
1147 ptrace_unfreeze_traced(child);
1148
1149 out_put_task_struct:
1150 put_task_struct(child);
1151 out:
1152 return ret;
1153}
1154
1155int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1156 unsigned long data)
1157{
1158 unsigned long tmp;
1159 int copied;
1160
1161 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1162 if (copied != sizeof(tmp))
1163 return -EIO;
1164 return put_user(tmp, (unsigned long __user *)data);
1165}
1166
1167int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1168 unsigned long data)
1169{
1170 int copied;
1171
1172 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1173 FOLL_FORCE | FOLL_WRITE);
1174 return (copied == sizeof(data)) ? 0 : -EIO;
1175}
1176
1177#if defined CONFIG_COMPAT
1178
1179int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1180 compat_ulong_t addr, compat_ulong_t data)
1181{
1182 compat_ulong_t __user *datap = compat_ptr(data);
1183 compat_ulong_t word;
1184 siginfo_t siginfo;
1185 int ret;
1186
1187 switch (request) {
1188 case PTRACE_PEEKTEXT:
1189 case PTRACE_PEEKDATA:
1190 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1191 FOLL_FORCE);
1192 if (ret != sizeof(word))
1193 ret = -EIO;
1194 else
1195 ret = put_user(word, datap);
1196 break;
1197
1198 case PTRACE_POKETEXT:
1199 case PTRACE_POKEDATA:
1200 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1201 FOLL_FORCE | FOLL_WRITE);
1202 ret = (ret != sizeof(data) ? -EIO : 0);
1203 break;
1204
1205 case PTRACE_GETEVENTMSG:
1206 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1207 break;
1208
1209 case PTRACE_GETSIGINFO:
1210 ret = ptrace_getsiginfo(child, &siginfo);
1211 if (!ret)
1212 ret = copy_siginfo_to_user32(
1213 (struct compat_siginfo __user *) datap,
1214 &siginfo);
1215 break;
1216
1217 case PTRACE_SETSIGINFO:
1218 if (copy_siginfo_from_user32(
1219 &siginfo, (struct compat_siginfo __user *) datap))
1220 ret = -EFAULT;
1221 else
1222 ret = ptrace_setsiginfo(child, &siginfo);
1223 break;
1224#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1225 case PTRACE_GETREGSET:
1226 case PTRACE_SETREGSET:
1227 {
1228 struct iovec kiov;
1229 struct compat_iovec __user *uiov =
1230 (struct compat_iovec __user *) datap;
1231 compat_uptr_t ptr;
1232 compat_size_t len;
1233
1234 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1235 return -EFAULT;
1236
1237 if (__get_user(ptr, &uiov->iov_base) ||
1238 __get_user(len, &uiov->iov_len))
1239 return -EFAULT;
1240
1241 kiov.iov_base = compat_ptr(ptr);
1242 kiov.iov_len = len;
1243
1244 ret = ptrace_regset(child, request, addr, &kiov);
1245 if (!ret)
1246 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1247 break;
1248 }
1249#endif
1250
1251 default:
1252 ret = ptrace_request(child, request, addr, data);
1253 }
1254
1255 return ret;
1256}
1257
1258COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1259 compat_long_t, addr, compat_long_t, data)
1260{
1261 struct task_struct *child;
1262 long ret;
1263
1264 if (request == PTRACE_TRACEME) {
1265 ret = ptrace_traceme();
1266 goto out;
1267 }
1268
1269 child = find_get_task_by_vpid(pid);
1270 if (!child) {
1271 ret = -ESRCH;
1272 goto out;
1273 }
1274
1275 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1276 ret = ptrace_attach(child, request, addr, data);
1277 /*
1278 * Some architectures need to do book-keeping after
1279 * a ptrace attach.
1280 */
1281 if (!ret)
1282 arch_ptrace_attach(child);
1283 goto out_put_task_struct;
1284 }
1285
1286 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1287 request == PTRACE_INTERRUPT);
1288 if (!ret) {
1289 ret = compat_arch_ptrace(child, request, addr, data);
1290 if (ret || request != PTRACE_DETACH)
1291 ptrace_unfreeze_traced(child);
1292 }
1293
1294 out_put_task_struct:
1295 put_task_struct(child);
1296 out:
1297 return ret;
1298}
1299#endif /* CONFIG_COMPAT */