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