Loading...
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 */
1/*
2 * linux/kernel/ptrace.c
3 *
4 * (C) Copyright 1999 Linus Torvalds
5 *
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
8 */
9
10#include <linux/capability.h>
11#include <linux/export.h>
12#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/mm.h>
15#include <linux/highmem.h>
16#include <linux/pagemap.h>
17#include <linux/ptrace.h>
18#include <linux/security.h>
19#include <linux/signal.h>
20#include <linux/uio.h>
21#include <linux/audit.h>
22#include <linux/pid_namespace.h>
23#include <linux/syscalls.h>
24#include <linux/uaccess.h>
25#include <linux/regset.h>
26#include <linux/hw_breakpoint.h>
27#include <linux/cn_proc.h>
28#include <linux/compat.h>
29
30
31/*
32 * ptrace a task: make the debugger its new parent and
33 * move it to the ptrace list.
34 *
35 * Must be called with the tasklist lock write-held.
36 */
37void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
38{
39 BUG_ON(!list_empty(&child->ptrace_entry));
40 list_add(&child->ptrace_entry, &new_parent->ptraced);
41 child->parent = new_parent;
42}
43
44/**
45 * __ptrace_unlink - unlink ptracee and restore its execution state
46 * @child: ptracee to be unlinked
47 *
48 * Remove @child from the ptrace list, move it back to the original parent,
49 * and restore the execution state so that it conforms to the group stop
50 * state.
51 *
52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
55 * If the ptracer is exiting, the ptracee can be in any state.
56 *
57 * After detach, the ptracee should be in a state which conforms to the
58 * group stop. If the group is stopped or in the process of stopping, the
59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
60 * up from TASK_TRACED.
61 *
62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
64 * to but in the opposite direction of what happens while attaching to a
65 * stopped task. However, in this direction, the intermediate RUNNING
66 * state is not hidden even from the current ptracer and if it immediately
67 * re-attaches and performs a WNOHANG wait(2), it may fail.
68 *
69 * CONTEXT:
70 * write_lock_irq(tasklist_lock)
71 */
72void __ptrace_unlink(struct task_struct *child)
73{
74 BUG_ON(!child->ptrace);
75
76 child->parent = child->real_parent;
77 list_del_init(&child->ptrace_entry);
78
79 spin_lock(&child->sighand->siglock);
80 child->ptrace = 0;
81 /*
82 * Clear all pending traps and TRAPPING. TRAPPING should be
83 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
84 */
85 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
86 task_clear_jobctl_trapping(child);
87
88 /*
89 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
90 * @child isn't dead.
91 */
92 if (!(child->flags & PF_EXITING) &&
93 (child->signal->flags & SIGNAL_STOP_STOPPED ||
94 child->signal->group_stop_count)) {
95 child->jobctl |= JOBCTL_STOP_PENDING;
96
97 /*
98 * This is only possible if this thread was cloned by the
99 * traced task running in the stopped group, set the signal
100 * for the future reports.
101 * FIXME: we should change ptrace_init_task() to handle this
102 * case.
103 */
104 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
105 child->jobctl |= SIGSTOP;
106 }
107
108 /*
109 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
110 * @child in the butt. Note that @resume should be used iff @child
111 * is in TASK_TRACED; otherwise, we might unduly disrupt
112 * TASK_KILLABLE sleeps.
113 */
114 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
115 ptrace_signal_wake_up(child, true);
116
117 spin_unlock(&child->sighand->siglock);
118}
119
120/* Ensure that nothing can wake it up, even SIGKILL */
121static bool ptrace_freeze_traced(struct task_struct *task)
122{
123 bool ret = false;
124
125 /* Lockless, nobody but us can set this flag */
126 if (task->jobctl & JOBCTL_LISTENING)
127 return ret;
128
129 spin_lock_irq(&task->sighand->siglock);
130 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
131 task->state = __TASK_TRACED;
132 ret = true;
133 }
134 spin_unlock_irq(&task->sighand->siglock);
135
136 return ret;
137}
138
139static void ptrace_unfreeze_traced(struct task_struct *task)
140{
141 if (task->state != __TASK_TRACED)
142 return;
143
144 WARN_ON(!task->ptrace || task->parent != current);
145
146 spin_lock_irq(&task->sighand->siglock);
147 if (__fatal_signal_pending(task))
148 wake_up_state(task, __TASK_TRACED);
149 else
150 task->state = TASK_TRACED;
151 spin_unlock_irq(&task->sighand->siglock);
152}
153
154/**
155 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
156 * @child: ptracee to check for
157 * @ignore_state: don't check whether @child is currently %TASK_TRACED
158 *
159 * Check whether @child is being ptraced by %current and ready for further
160 * ptrace operations. If @ignore_state is %false, @child also should be in
161 * %TASK_TRACED state and on return the child is guaranteed to be traced
162 * and not executing. If @ignore_state is %true, @child can be in any
163 * state.
164 *
165 * CONTEXT:
166 * Grabs and releases tasklist_lock and @child->sighand->siglock.
167 *
168 * RETURNS:
169 * 0 on success, -ESRCH if %child is not ready.
170 */
171static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
172{
173 int ret = -ESRCH;
174
175 /*
176 * We take the read lock around doing both checks to close a
177 * possible race where someone else was tracing our child and
178 * detached between these two checks. After this locked check,
179 * we are sure that this is our traced child and that can only
180 * be changed by us so it's not changing right after this.
181 */
182 read_lock(&tasklist_lock);
183 if (child->ptrace && child->parent == current) {
184 WARN_ON(child->state == __TASK_TRACED);
185 /*
186 * child->sighand can't be NULL, release_task()
187 * does ptrace_unlink() before __exit_signal().
188 */
189 if (ignore_state || ptrace_freeze_traced(child))
190 ret = 0;
191 }
192 read_unlock(&tasklist_lock);
193
194 if (!ret && !ignore_state) {
195 if (!wait_task_inactive(child, __TASK_TRACED)) {
196 /*
197 * This can only happen if may_ptrace_stop() fails and
198 * ptrace_stop() changes ->state back to TASK_RUNNING,
199 * so we should not worry about leaking __TASK_TRACED.
200 */
201 WARN_ON(child->state == __TASK_TRACED);
202 ret = -ESRCH;
203 }
204 }
205
206 return ret;
207}
208
209static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
210{
211 if (mode & PTRACE_MODE_NOAUDIT)
212 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
213 else
214 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
215}
216
217/* Returns 0 on success, -errno on denial. */
218static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
219{
220 const struct cred *cred = current_cred(), *tcred;
221 int dumpable = 0;
222 kuid_t caller_uid;
223 kgid_t caller_gid;
224
225 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
226 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
227 return -EPERM;
228 }
229
230 /* May we inspect the given task?
231 * This check is used both for attaching with ptrace
232 * and for allowing access to sensitive information in /proc.
233 *
234 * ptrace_attach denies several cases that /proc allows
235 * because setting up the necessary parent/child relationship
236 * or halting the specified task is impossible.
237 */
238
239 /* Don't let security modules deny introspection */
240 if (same_thread_group(task, current))
241 return 0;
242 rcu_read_lock();
243 if (mode & PTRACE_MODE_FSCREDS) {
244 caller_uid = cred->fsuid;
245 caller_gid = cred->fsgid;
246 } else {
247 /*
248 * Using the euid would make more sense here, but something
249 * in userland might rely on the old behavior, and this
250 * shouldn't be a security problem since
251 * PTRACE_MODE_REALCREDS implies that the caller explicitly
252 * used a syscall that requests access to another process
253 * (and not a filesystem syscall to procfs).
254 */
255 caller_uid = cred->uid;
256 caller_gid = cred->gid;
257 }
258 tcred = __task_cred(task);
259 if (uid_eq(caller_uid, tcred->euid) &&
260 uid_eq(caller_uid, tcred->suid) &&
261 uid_eq(caller_uid, tcred->uid) &&
262 gid_eq(caller_gid, tcred->egid) &&
263 gid_eq(caller_gid, tcred->sgid) &&
264 gid_eq(caller_gid, tcred->gid))
265 goto ok;
266 if (ptrace_has_cap(tcred->user_ns, mode))
267 goto ok;
268 rcu_read_unlock();
269 return -EPERM;
270ok:
271 rcu_read_unlock();
272 smp_rmb();
273 if (task->mm)
274 dumpable = get_dumpable(task->mm);
275 rcu_read_lock();
276 if (dumpable != SUID_DUMP_USER &&
277 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
278 rcu_read_unlock();
279 return -EPERM;
280 }
281 rcu_read_unlock();
282
283 return security_ptrace_access_check(task, mode);
284}
285
286bool ptrace_may_access(struct task_struct *task, unsigned int mode)
287{
288 int err;
289 task_lock(task);
290 err = __ptrace_may_access(task, mode);
291 task_unlock(task);
292 return !err;
293}
294
295static int ptrace_attach(struct task_struct *task, long request,
296 unsigned long addr,
297 unsigned long flags)
298{
299 bool seize = (request == PTRACE_SEIZE);
300 int retval;
301
302 retval = -EIO;
303 if (seize) {
304 if (addr != 0)
305 goto out;
306 if (flags & ~(unsigned long)PTRACE_O_MASK)
307 goto out;
308 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
309 } else {
310 flags = PT_PTRACED;
311 }
312
313 audit_ptrace(task);
314
315 retval = -EPERM;
316 if (unlikely(task->flags & PF_KTHREAD))
317 goto out;
318 if (same_thread_group(task, current))
319 goto out;
320
321 /*
322 * Protect exec's credential calculations against our interference;
323 * SUID, SGID and LSM creds get determined differently
324 * under ptrace.
325 */
326 retval = -ERESTARTNOINTR;
327 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
328 goto out;
329
330 task_lock(task);
331 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
332 task_unlock(task);
333 if (retval)
334 goto unlock_creds;
335
336 write_lock_irq(&tasklist_lock);
337 retval = -EPERM;
338 if (unlikely(task->exit_state))
339 goto unlock_tasklist;
340 if (task->ptrace)
341 goto unlock_tasklist;
342
343 if (seize)
344 flags |= PT_SEIZED;
345 rcu_read_lock();
346 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
347 flags |= PT_PTRACE_CAP;
348 rcu_read_unlock();
349 task->ptrace = flags;
350
351 __ptrace_link(task, current);
352
353 /* SEIZE doesn't trap tracee on attach */
354 if (!seize)
355 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
356
357 spin_lock(&task->sighand->siglock);
358
359 /*
360 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
361 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
362 * will be cleared if the child completes the transition or any
363 * event which clears the group stop states happens. We'll wait
364 * for the transition to complete before returning from this
365 * function.
366 *
367 * This hides STOPPED -> RUNNING -> TRACED transition from the
368 * attaching thread but a different thread in the same group can
369 * still observe the transient RUNNING state. IOW, if another
370 * thread's WNOHANG wait(2) on the stopped tracee races against
371 * ATTACH, the wait(2) may fail due to the transient RUNNING.
372 *
373 * The following task_is_stopped() test is safe as both transitions
374 * in and out of STOPPED are protected by siglock.
375 */
376 if (task_is_stopped(task) &&
377 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
378 signal_wake_up_state(task, __TASK_STOPPED);
379
380 spin_unlock(&task->sighand->siglock);
381
382 retval = 0;
383unlock_tasklist:
384 write_unlock_irq(&tasklist_lock);
385unlock_creds:
386 mutex_unlock(&task->signal->cred_guard_mutex);
387out:
388 if (!retval) {
389 /*
390 * We do not bother to change retval or clear JOBCTL_TRAPPING
391 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
392 * not return to user-mode, it will exit and clear this bit in
393 * __ptrace_unlink() if it wasn't already cleared by the tracee;
394 * and until then nobody can ptrace this task.
395 */
396 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
397 proc_ptrace_connector(task, PTRACE_ATTACH);
398 }
399
400 return retval;
401}
402
403/**
404 * ptrace_traceme -- helper for PTRACE_TRACEME
405 *
406 * Performs checks and sets PT_PTRACED.
407 * Should be used by all ptrace implementations for PTRACE_TRACEME.
408 */
409static int ptrace_traceme(void)
410{
411 int ret = -EPERM;
412
413 write_lock_irq(&tasklist_lock);
414 /* Are we already being traced? */
415 if (!current->ptrace) {
416 ret = security_ptrace_traceme(current->parent);
417 /*
418 * Check PF_EXITING to ensure ->real_parent has not passed
419 * exit_ptrace(). Otherwise we don't report the error but
420 * pretend ->real_parent untraces us right after return.
421 */
422 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
423 current->ptrace = PT_PTRACED;
424 __ptrace_link(current, current->real_parent);
425 }
426 }
427 write_unlock_irq(&tasklist_lock);
428
429 return ret;
430}
431
432/*
433 * Called with irqs disabled, returns true if childs should reap themselves.
434 */
435static int ignoring_children(struct sighand_struct *sigh)
436{
437 int ret;
438 spin_lock(&sigh->siglock);
439 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
440 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
441 spin_unlock(&sigh->siglock);
442 return ret;
443}
444
445/*
446 * Called with tasklist_lock held for writing.
447 * Unlink a traced task, and clean it up if it was a traced zombie.
448 * Return true if it needs to be reaped with release_task().
449 * (We can't call release_task() here because we already hold tasklist_lock.)
450 *
451 * If it's a zombie, our attachedness prevented normal parent notification
452 * or self-reaping. Do notification now if it would have happened earlier.
453 * If it should reap itself, return true.
454 *
455 * If it's our own child, there is no notification to do. But if our normal
456 * children self-reap, then this child was prevented by ptrace and we must
457 * reap it now, in that case we must also wake up sub-threads sleeping in
458 * do_wait().
459 */
460static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
461{
462 bool dead;
463
464 __ptrace_unlink(p);
465
466 if (p->exit_state != EXIT_ZOMBIE)
467 return false;
468
469 dead = !thread_group_leader(p);
470
471 if (!dead && thread_group_empty(p)) {
472 if (!same_thread_group(p->real_parent, tracer))
473 dead = do_notify_parent(p, p->exit_signal);
474 else if (ignoring_children(tracer->sighand)) {
475 __wake_up_parent(p, tracer);
476 dead = true;
477 }
478 }
479 /* Mark it as in the process of being reaped. */
480 if (dead)
481 p->exit_state = EXIT_DEAD;
482 return dead;
483}
484
485static int ptrace_detach(struct task_struct *child, unsigned int data)
486{
487 if (!valid_signal(data))
488 return -EIO;
489
490 /* Architecture-specific hardware disable .. */
491 ptrace_disable(child);
492 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
493
494 write_lock_irq(&tasklist_lock);
495 /*
496 * We rely on ptrace_freeze_traced(). It can't be killed and
497 * untraced by another thread, it can't be a zombie.
498 */
499 WARN_ON(!child->ptrace || child->exit_state);
500 /*
501 * tasklist_lock avoids the race with wait_task_stopped(), see
502 * the comment in ptrace_resume().
503 */
504 child->exit_code = data;
505 __ptrace_detach(current, child);
506 write_unlock_irq(&tasklist_lock);
507
508 proc_ptrace_connector(child, PTRACE_DETACH);
509
510 return 0;
511}
512
513/*
514 * Detach all tasks we were using ptrace on. Called with tasklist held
515 * for writing.
516 */
517void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
518{
519 struct task_struct *p, *n;
520
521 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
522 if (unlikely(p->ptrace & PT_EXITKILL))
523 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
524
525 if (__ptrace_detach(tracer, p))
526 list_add(&p->ptrace_entry, dead);
527 }
528}
529
530int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
531{
532 int copied = 0;
533
534 while (len > 0) {
535 char buf[128];
536 int this_len, retval;
537
538 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
539 retval = access_process_vm(tsk, src, buf, this_len, 0);
540 if (!retval) {
541 if (copied)
542 break;
543 return -EIO;
544 }
545 if (copy_to_user(dst, buf, retval))
546 return -EFAULT;
547 copied += retval;
548 src += retval;
549 dst += retval;
550 len -= retval;
551 }
552 return copied;
553}
554
555int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
556{
557 int copied = 0;
558
559 while (len > 0) {
560 char buf[128];
561 int this_len, retval;
562
563 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
564 if (copy_from_user(buf, src, this_len))
565 return -EFAULT;
566 retval = access_process_vm(tsk, dst, buf, this_len, 1);
567 if (!retval) {
568 if (copied)
569 break;
570 return -EIO;
571 }
572 copied += retval;
573 src += retval;
574 dst += retval;
575 len -= retval;
576 }
577 return copied;
578}
579
580static int ptrace_setoptions(struct task_struct *child, unsigned long data)
581{
582 unsigned flags;
583
584 if (data & ~(unsigned long)PTRACE_O_MASK)
585 return -EINVAL;
586
587 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
588 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
589 !config_enabled(CONFIG_SECCOMP))
590 return -EINVAL;
591
592 if (!capable(CAP_SYS_ADMIN))
593 return -EPERM;
594
595 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
596 current->ptrace & PT_SUSPEND_SECCOMP)
597 return -EPERM;
598 }
599
600 /* Avoid intermediate state when all opts are cleared */
601 flags = child->ptrace;
602 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
603 flags |= (data << PT_OPT_FLAG_SHIFT);
604 child->ptrace = flags;
605
606 return 0;
607}
608
609static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
610{
611 unsigned long flags;
612 int error = -ESRCH;
613
614 if (lock_task_sighand(child, &flags)) {
615 error = -EINVAL;
616 if (likely(child->last_siginfo != NULL)) {
617 *info = *child->last_siginfo;
618 error = 0;
619 }
620 unlock_task_sighand(child, &flags);
621 }
622 return error;
623}
624
625static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
626{
627 unsigned long flags;
628 int error = -ESRCH;
629
630 if (lock_task_sighand(child, &flags)) {
631 error = -EINVAL;
632 if (likely(child->last_siginfo != NULL)) {
633 *child->last_siginfo = *info;
634 error = 0;
635 }
636 unlock_task_sighand(child, &flags);
637 }
638 return error;
639}
640
641static int ptrace_peek_siginfo(struct task_struct *child,
642 unsigned long addr,
643 unsigned long data)
644{
645 struct ptrace_peeksiginfo_args arg;
646 struct sigpending *pending;
647 struct sigqueue *q;
648 int ret, i;
649
650 ret = copy_from_user(&arg, (void __user *) addr,
651 sizeof(struct ptrace_peeksiginfo_args));
652 if (ret)
653 return -EFAULT;
654
655 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
656 return -EINVAL; /* unknown flags */
657
658 if (arg.nr < 0)
659 return -EINVAL;
660
661 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
662 pending = &child->signal->shared_pending;
663 else
664 pending = &child->pending;
665
666 for (i = 0; i < arg.nr; ) {
667 siginfo_t info;
668 s32 off = arg.off + i;
669
670 spin_lock_irq(&child->sighand->siglock);
671 list_for_each_entry(q, &pending->list, list) {
672 if (!off--) {
673 copy_siginfo(&info, &q->info);
674 break;
675 }
676 }
677 spin_unlock_irq(&child->sighand->siglock);
678
679 if (off >= 0) /* beyond the end of the list */
680 break;
681
682#ifdef CONFIG_COMPAT
683 if (unlikely(in_compat_syscall())) {
684 compat_siginfo_t __user *uinfo = compat_ptr(data);
685
686 if (copy_siginfo_to_user32(uinfo, &info) ||
687 __put_user(info.si_code, &uinfo->si_code)) {
688 ret = -EFAULT;
689 break;
690 }
691
692 } else
693#endif
694 {
695 siginfo_t __user *uinfo = (siginfo_t __user *) data;
696
697 if (copy_siginfo_to_user(uinfo, &info) ||
698 __put_user(info.si_code, &uinfo->si_code)) {
699 ret = -EFAULT;
700 break;
701 }
702 }
703
704 data += sizeof(siginfo_t);
705 i++;
706
707 if (signal_pending(current))
708 break;
709
710 cond_resched();
711 }
712
713 if (i > 0)
714 return i;
715
716 return ret;
717}
718
719#ifdef PTRACE_SINGLESTEP
720#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
721#else
722#define is_singlestep(request) 0
723#endif
724
725#ifdef PTRACE_SINGLEBLOCK
726#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
727#else
728#define is_singleblock(request) 0
729#endif
730
731#ifdef PTRACE_SYSEMU
732#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
733#else
734#define is_sysemu_singlestep(request) 0
735#endif
736
737static int ptrace_resume(struct task_struct *child, long request,
738 unsigned long data)
739{
740 bool need_siglock;
741
742 if (!valid_signal(data))
743 return -EIO;
744
745 if (request == PTRACE_SYSCALL)
746 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
747 else
748 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
749
750#ifdef TIF_SYSCALL_EMU
751 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
752 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
753 else
754 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
755#endif
756
757 if (is_singleblock(request)) {
758 if (unlikely(!arch_has_block_step()))
759 return -EIO;
760 user_enable_block_step(child);
761 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
762 if (unlikely(!arch_has_single_step()))
763 return -EIO;
764 user_enable_single_step(child);
765 } else {
766 user_disable_single_step(child);
767 }
768
769 /*
770 * Change ->exit_code and ->state under siglock to avoid the race
771 * with wait_task_stopped() in between; a non-zero ->exit_code will
772 * wrongly look like another report from tracee.
773 *
774 * Note that we need siglock even if ->exit_code == data and/or this
775 * status was not reported yet, the new status must not be cleared by
776 * wait_task_stopped() after resume.
777 *
778 * If data == 0 we do not care if wait_task_stopped() reports the old
779 * status and clears the code too; this can't race with the tracee, it
780 * takes siglock after resume.
781 */
782 need_siglock = data && !thread_group_empty(current);
783 if (need_siglock)
784 spin_lock_irq(&child->sighand->siglock);
785 child->exit_code = data;
786 wake_up_state(child, __TASK_TRACED);
787 if (need_siglock)
788 spin_unlock_irq(&child->sighand->siglock);
789
790 return 0;
791}
792
793#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
794
795static const struct user_regset *
796find_regset(const struct user_regset_view *view, unsigned int type)
797{
798 const struct user_regset *regset;
799 int n;
800
801 for (n = 0; n < view->n; ++n) {
802 regset = view->regsets + n;
803 if (regset->core_note_type == type)
804 return regset;
805 }
806
807 return NULL;
808}
809
810static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
811 struct iovec *kiov)
812{
813 const struct user_regset_view *view = task_user_regset_view(task);
814 const struct user_regset *regset = find_regset(view, type);
815 int regset_no;
816
817 if (!regset || (kiov->iov_len % regset->size) != 0)
818 return -EINVAL;
819
820 regset_no = regset - view->regsets;
821 kiov->iov_len = min(kiov->iov_len,
822 (__kernel_size_t) (regset->n * regset->size));
823
824 if (req == PTRACE_GETREGSET)
825 return copy_regset_to_user(task, view, regset_no, 0,
826 kiov->iov_len, kiov->iov_base);
827 else
828 return copy_regset_from_user(task, view, regset_no, 0,
829 kiov->iov_len, kiov->iov_base);
830}
831
832/*
833 * This is declared in linux/regset.h and defined in machine-dependent
834 * code. We put the export here, near the primary machine-neutral use,
835 * to ensure no machine forgets it.
836 */
837EXPORT_SYMBOL_GPL(task_user_regset_view);
838#endif
839
840int ptrace_request(struct task_struct *child, long request,
841 unsigned long addr, unsigned long data)
842{
843 bool seized = child->ptrace & PT_SEIZED;
844 int ret = -EIO;
845 siginfo_t siginfo, *si;
846 void __user *datavp = (void __user *) data;
847 unsigned long __user *datalp = datavp;
848 unsigned long flags;
849
850 switch (request) {
851 case PTRACE_PEEKTEXT:
852 case PTRACE_PEEKDATA:
853 return generic_ptrace_peekdata(child, addr, data);
854 case PTRACE_POKETEXT:
855 case PTRACE_POKEDATA:
856 return generic_ptrace_pokedata(child, addr, data);
857
858#ifdef PTRACE_OLDSETOPTIONS
859 case PTRACE_OLDSETOPTIONS:
860#endif
861 case PTRACE_SETOPTIONS:
862 ret = ptrace_setoptions(child, data);
863 break;
864 case PTRACE_GETEVENTMSG:
865 ret = put_user(child->ptrace_message, datalp);
866 break;
867
868 case PTRACE_PEEKSIGINFO:
869 ret = ptrace_peek_siginfo(child, addr, data);
870 break;
871
872 case PTRACE_GETSIGINFO:
873 ret = ptrace_getsiginfo(child, &siginfo);
874 if (!ret)
875 ret = copy_siginfo_to_user(datavp, &siginfo);
876 break;
877
878 case PTRACE_SETSIGINFO:
879 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
880 ret = -EFAULT;
881 else
882 ret = ptrace_setsiginfo(child, &siginfo);
883 break;
884
885 case PTRACE_GETSIGMASK:
886 if (addr != sizeof(sigset_t)) {
887 ret = -EINVAL;
888 break;
889 }
890
891 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
892 ret = -EFAULT;
893 else
894 ret = 0;
895
896 break;
897
898 case PTRACE_SETSIGMASK: {
899 sigset_t new_set;
900
901 if (addr != sizeof(sigset_t)) {
902 ret = -EINVAL;
903 break;
904 }
905
906 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
907 ret = -EFAULT;
908 break;
909 }
910
911 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
912
913 /*
914 * Every thread does recalc_sigpending() after resume, so
915 * retarget_shared_pending() and recalc_sigpending() are not
916 * called here.
917 */
918 spin_lock_irq(&child->sighand->siglock);
919 child->blocked = new_set;
920 spin_unlock_irq(&child->sighand->siglock);
921
922 ret = 0;
923 break;
924 }
925
926 case PTRACE_INTERRUPT:
927 /*
928 * Stop tracee without any side-effect on signal or job
929 * control. At least one trap is guaranteed to happen
930 * after this request. If @child is already trapped, the
931 * current trap is not disturbed and another trap will
932 * happen after the current trap is ended with PTRACE_CONT.
933 *
934 * The actual trap might not be PTRACE_EVENT_STOP trap but
935 * the pending condition is cleared regardless.
936 */
937 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
938 break;
939
940 /*
941 * INTERRUPT doesn't disturb existing trap sans one
942 * exception. If ptracer issued LISTEN for the current
943 * STOP, this INTERRUPT should clear LISTEN and re-trap
944 * tracee into STOP.
945 */
946 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
947 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
948
949 unlock_task_sighand(child, &flags);
950 ret = 0;
951 break;
952
953 case PTRACE_LISTEN:
954 /*
955 * Listen for events. Tracee must be in STOP. It's not
956 * resumed per-se but is not considered to be in TRACED by
957 * wait(2) or ptrace(2). If an async event (e.g. group
958 * stop state change) happens, tracee will enter STOP trap
959 * again. Alternatively, ptracer can issue INTERRUPT to
960 * finish listening and re-trap tracee into STOP.
961 */
962 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
963 break;
964
965 si = child->last_siginfo;
966 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
967 child->jobctl |= JOBCTL_LISTENING;
968 /*
969 * If NOTIFY is set, it means event happened between
970 * start of this trap and now. Trigger re-trap.
971 */
972 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
973 ptrace_signal_wake_up(child, true);
974 ret = 0;
975 }
976 unlock_task_sighand(child, &flags);
977 break;
978
979 case PTRACE_DETACH: /* detach a process that was attached. */
980 ret = ptrace_detach(child, data);
981 break;
982
983#ifdef CONFIG_BINFMT_ELF_FDPIC
984 case PTRACE_GETFDPIC: {
985 struct mm_struct *mm = get_task_mm(child);
986 unsigned long tmp = 0;
987
988 ret = -ESRCH;
989 if (!mm)
990 break;
991
992 switch (addr) {
993 case PTRACE_GETFDPIC_EXEC:
994 tmp = mm->context.exec_fdpic_loadmap;
995 break;
996 case PTRACE_GETFDPIC_INTERP:
997 tmp = mm->context.interp_fdpic_loadmap;
998 break;
999 default:
1000 break;
1001 }
1002 mmput(mm);
1003
1004 ret = put_user(tmp, datalp);
1005 break;
1006 }
1007#endif
1008
1009#ifdef PTRACE_SINGLESTEP
1010 case PTRACE_SINGLESTEP:
1011#endif
1012#ifdef PTRACE_SINGLEBLOCK
1013 case PTRACE_SINGLEBLOCK:
1014#endif
1015#ifdef PTRACE_SYSEMU
1016 case PTRACE_SYSEMU:
1017 case PTRACE_SYSEMU_SINGLESTEP:
1018#endif
1019 case PTRACE_SYSCALL:
1020 case PTRACE_CONT:
1021 return ptrace_resume(child, request, data);
1022
1023 case PTRACE_KILL:
1024 if (child->exit_state) /* already dead */
1025 return 0;
1026 return ptrace_resume(child, request, SIGKILL);
1027
1028#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1029 case PTRACE_GETREGSET:
1030 case PTRACE_SETREGSET: {
1031 struct iovec kiov;
1032 struct iovec __user *uiov = datavp;
1033
1034 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1035 return -EFAULT;
1036
1037 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1038 __get_user(kiov.iov_len, &uiov->iov_len))
1039 return -EFAULT;
1040
1041 ret = ptrace_regset(child, request, addr, &kiov);
1042 if (!ret)
1043 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1044 break;
1045 }
1046#endif
1047
1048 case PTRACE_SECCOMP_GET_FILTER:
1049 ret = seccomp_get_filter(child, addr, datavp);
1050 break;
1051
1052 default:
1053 break;
1054 }
1055
1056 return ret;
1057}
1058
1059static struct task_struct *ptrace_get_task_struct(pid_t pid)
1060{
1061 struct task_struct *child;
1062
1063 rcu_read_lock();
1064 child = find_task_by_vpid(pid);
1065 if (child)
1066 get_task_struct(child);
1067 rcu_read_unlock();
1068
1069 if (!child)
1070 return ERR_PTR(-ESRCH);
1071 return child;
1072}
1073
1074#ifndef arch_ptrace_attach
1075#define arch_ptrace_attach(child) do { } while (0)
1076#endif
1077
1078SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1079 unsigned long, data)
1080{
1081 struct task_struct *child;
1082 long ret;
1083
1084 if (request == PTRACE_TRACEME) {
1085 ret = ptrace_traceme();
1086 if (!ret)
1087 arch_ptrace_attach(current);
1088 goto out;
1089 }
1090
1091 child = ptrace_get_task_struct(pid);
1092 if (IS_ERR(child)) {
1093 ret = PTR_ERR(child);
1094 goto out;
1095 }
1096
1097 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1098 ret = ptrace_attach(child, request, addr, data);
1099 /*
1100 * Some architectures need to do book-keeping after
1101 * a ptrace attach.
1102 */
1103 if (!ret)
1104 arch_ptrace_attach(child);
1105 goto out_put_task_struct;
1106 }
1107
1108 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1109 request == PTRACE_INTERRUPT);
1110 if (ret < 0)
1111 goto out_put_task_struct;
1112
1113 ret = arch_ptrace(child, request, addr, data);
1114 if (ret || request != PTRACE_DETACH)
1115 ptrace_unfreeze_traced(child);
1116
1117 out_put_task_struct:
1118 put_task_struct(child);
1119 out:
1120 return ret;
1121}
1122
1123int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1124 unsigned long data)
1125{
1126 unsigned long tmp;
1127 int copied;
1128
1129 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1130 if (copied != sizeof(tmp))
1131 return -EIO;
1132 return put_user(tmp, (unsigned long __user *)data);
1133}
1134
1135int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1136 unsigned long data)
1137{
1138 int copied;
1139
1140 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1141 return (copied == sizeof(data)) ? 0 : -EIO;
1142}
1143
1144#if defined CONFIG_COMPAT
1145
1146int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1147 compat_ulong_t addr, compat_ulong_t data)
1148{
1149 compat_ulong_t __user *datap = compat_ptr(data);
1150 compat_ulong_t word;
1151 siginfo_t siginfo;
1152 int ret;
1153
1154 switch (request) {
1155 case PTRACE_PEEKTEXT:
1156 case PTRACE_PEEKDATA:
1157 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1158 if (ret != sizeof(word))
1159 ret = -EIO;
1160 else
1161 ret = put_user(word, datap);
1162 break;
1163
1164 case PTRACE_POKETEXT:
1165 case PTRACE_POKEDATA:
1166 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1167 ret = (ret != sizeof(data) ? -EIO : 0);
1168 break;
1169
1170 case PTRACE_GETEVENTMSG:
1171 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1172 break;
1173
1174 case PTRACE_GETSIGINFO:
1175 ret = ptrace_getsiginfo(child, &siginfo);
1176 if (!ret)
1177 ret = copy_siginfo_to_user32(
1178 (struct compat_siginfo __user *) datap,
1179 &siginfo);
1180 break;
1181
1182 case PTRACE_SETSIGINFO:
1183 memset(&siginfo, 0, sizeof siginfo);
1184 if (copy_siginfo_from_user32(
1185 &siginfo, (struct compat_siginfo __user *) datap))
1186 ret = -EFAULT;
1187 else
1188 ret = ptrace_setsiginfo(child, &siginfo);
1189 break;
1190#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1191 case PTRACE_GETREGSET:
1192 case PTRACE_SETREGSET:
1193 {
1194 struct iovec kiov;
1195 struct compat_iovec __user *uiov =
1196 (struct compat_iovec __user *) datap;
1197 compat_uptr_t ptr;
1198 compat_size_t len;
1199
1200 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1201 return -EFAULT;
1202
1203 if (__get_user(ptr, &uiov->iov_base) ||
1204 __get_user(len, &uiov->iov_len))
1205 return -EFAULT;
1206
1207 kiov.iov_base = compat_ptr(ptr);
1208 kiov.iov_len = len;
1209
1210 ret = ptrace_regset(child, request, addr, &kiov);
1211 if (!ret)
1212 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1213 break;
1214 }
1215#endif
1216
1217 default:
1218 ret = ptrace_request(child, request, addr, data);
1219 }
1220
1221 return ret;
1222}
1223
1224COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1225 compat_long_t, addr, compat_long_t, data)
1226{
1227 struct task_struct *child;
1228 long ret;
1229
1230 if (request == PTRACE_TRACEME) {
1231 ret = ptrace_traceme();
1232 goto out;
1233 }
1234
1235 child = ptrace_get_task_struct(pid);
1236 if (IS_ERR(child)) {
1237 ret = PTR_ERR(child);
1238 goto out;
1239 }
1240
1241 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1242 ret = ptrace_attach(child, request, addr, data);
1243 /*
1244 * Some architectures need to do book-keeping after
1245 * a ptrace attach.
1246 */
1247 if (!ret)
1248 arch_ptrace_attach(child);
1249 goto out_put_task_struct;
1250 }
1251
1252 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1253 request == PTRACE_INTERRUPT);
1254 if (!ret) {
1255 ret = compat_arch_ptrace(child, request, addr, data);
1256 if (ret || request != PTRACE_DETACH)
1257 ptrace_unfreeze_traced(child);
1258 }
1259
1260 out_put_task_struct:
1261 put_task_struct(child);
1262 out:
1263 return ret;
1264}
1265#endif /* CONFIG_COMPAT */