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