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