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TOMOYO Linux Cross Reference
Linux/kernel/ptrace.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/kernel/ptrace.c
  4  *
  5  * (C) Copyright 1999 Linus Torvalds
  6  *
  7  * Common interfaces for "ptrace()" which we do not want
  8  * to continually duplicate across every architecture.
  9  */
 10 
 11 #include <linux/capability.h>
 12 #include <linux/export.h>
 13 #include <linux/sched.h>
 14 #include <linux/sched/mm.h>
 15 #include <linux/sched/coredump.h>
 16 #include <linux/sched/task.h>
 17 #include <linux/errno.h>
 18 #include <linux/mm.h>
 19 #include <linux/highmem.h>
 20 #include <linux/pagemap.h>
 21 #include <linux/ptrace.h>
 22 #include <linux/security.h>
 23 #include <linux/signal.h>
 24 #include <linux/uio.h>
 25 #include <linux/audit.h>
 26 #include <linux/pid_namespace.h>
 27 #include <linux/syscalls.h>
 28 #include <linux/uaccess.h>
 29 #include <linux/regset.h>
 30 #include <linux/hw_breakpoint.h>
 31 #include <linux/cn_proc.h>
 32 #include <linux/compat.h>
 33 #include <linux/sched/signal.h>
 34 
 35 #include <asm/syscall.h>        /* for syscall_get_* */
 36 
 37 /*
 38  * Access another process' address space via ptrace.
 39  * Source/target buffer must be kernel space,
 40  * Do not walk the page table directly, use get_user_pages
 41  */
 42 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
 43                      void *buf, int len, unsigned int gup_flags)
 44 {
 45         struct mm_struct *mm;
 46         int ret;
 47 
 48         mm = get_task_mm(tsk);
 49         if (!mm)
 50                 return 0;
 51 
 52         if (!tsk->ptrace ||
 53             (current != tsk->parent) ||
 54             ((get_dumpable(mm) != SUID_DUMP_USER) &&
 55              !ptracer_capable(tsk, mm->user_ns))) {
 56                 mmput(mm);
 57                 return 0;
 58         }
 59 
 60         ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
 61         mmput(mm);
 62 
 63         return ret;
 64 }
 65 
 66 
 67 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
 68                    const struct cred *ptracer_cred)
 69 {
 70         BUG_ON(!list_empty(&child->ptrace_entry));
 71         list_add(&child->ptrace_entry, &new_parent->ptraced);
 72         child->parent = new_parent;
 73         child->ptracer_cred = get_cred(ptracer_cred);
 74 }
 75 
 76 /*
 77  * ptrace a task: make the debugger its new parent and
 78  * move it to the ptrace list.
 79  *
 80  * Must be called with the tasklist lock write-held.
 81  */
 82 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
 83 {
 84         __ptrace_link(child, new_parent, current_cred());
 85 }
 86 
 87 /**
 88  * __ptrace_unlink - unlink ptracee and restore its execution state
 89  * @child: ptracee to be unlinked
 90  *
 91  * Remove @child from the ptrace list, move it back to the original parent,
 92  * and restore the execution state so that it conforms to the group stop
 93  * state.
 94  *
 95  * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
 96  * exiting.  For PTRACE_DETACH, unless the ptracee has been killed between
 97  * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
 98  * If the ptracer is exiting, the ptracee can be in any state.
 99  *
100  * After detach, the ptracee should be in a state which conforms to the
101  * group stop.  If the group is stopped or in the process of stopping, the
102  * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
103  * up from TASK_TRACED.
104  *
105  * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
106  * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
107  * to but in the opposite direction of what happens while attaching to a
108  * stopped task.  However, in this direction, the intermediate RUNNING
109  * state is not hidden even from the current ptracer and if it immediately
110  * re-attaches and performs a WNOHANG wait(2), it may fail.
111  *
112  * CONTEXT:
113  * write_lock_irq(tasklist_lock)
114  */
115 void __ptrace_unlink(struct task_struct *child)
116 {
117         const struct cred *old_cred;
118         BUG_ON(!child->ptrace);
119 
120         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
121 #ifdef TIF_SYSCALL_EMU
122         clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
123 #endif
124 
125         child->parent = child->real_parent;
126         list_del_init(&child->ptrace_entry);
127         old_cred = child->ptracer_cred;
128         child->ptracer_cred = NULL;
129         put_cred(old_cred);
130 
131         spin_lock(&child->sighand->siglock);
132         child->ptrace = 0;
133         /*
134          * Clear all pending traps and TRAPPING.  TRAPPING should be
135          * cleared regardless of JOBCTL_STOP_PENDING.  Do it explicitly.
136          */
137         task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
138         task_clear_jobctl_trapping(child);
139 
140         /*
141          * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
142          * @child isn't dead.
143          */
144         if (!(child->flags & PF_EXITING) &&
145             (child->signal->flags & SIGNAL_STOP_STOPPED ||
146              child->signal->group_stop_count)) {
147                 child->jobctl |= JOBCTL_STOP_PENDING;
148 
149                 /*
150                  * This is only possible if this thread was cloned by the
151                  * traced task running in the stopped group, set the signal
152                  * for the future reports.
153                  * FIXME: we should change ptrace_init_task() to handle this
154                  * case.
155                  */
156                 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
157                         child->jobctl |= SIGSTOP;
158         }
159 
160         /*
161          * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
162          * @child in the butt.  Note that @resume should be used iff @child
163          * is in TASK_TRACED; otherwise, we might unduly disrupt
164          * TASK_KILLABLE sleeps.
165          */
166         if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
167                 ptrace_signal_wake_up(child, true);
168 
169         spin_unlock(&child->sighand->siglock);
170 }
171 
172 /* Ensure that nothing can wake it up, even SIGKILL */
173 static bool ptrace_freeze_traced(struct task_struct *task)
174 {
175         bool ret = false;
176 
177         /* Lockless, nobody but us can set this flag */
178         if (task->jobctl & JOBCTL_LISTENING)
179                 return ret;
180 
181         spin_lock_irq(&task->sighand->siglock);
182         if (task_is_traced(task) && !__fatal_signal_pending(task)) {
183                 task->state = __TASK_TRACED;
184                 ret = true;
185         }
186         spin_unlock_irq(&task->sighand->siglock);
187 
188         return ret;
189 }
190 
191 static void ptrace_unfreeze_traced(struct task_struct *task)
192 {
193         if (task->state != __TASK_TRACED)
194                 return;
195 
196         WARN_ON(!task->ptrace || task->parent != current);
197 
198         /*
199          * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
200          * Recheck state under the lock to close this race.
201          */
202         spin_lock_irq(&task->sighand->siglock);
203         if (task->state == __TASK_TRACED) {
204                 if (__fatal_signal_pending(task))
205                         wake_up_state(task, __TASK_TRACED);
206                 else
207                         task->state = TASK_TRACED;
208         }
209         spin_unlock_irq(&task->sighand->siglock);
210 }
211 
212 /**
213  * ptrace_check_attach - check whether ptracee is ready for ptrace operation
214  * @child: ptracee to check for
215  * @ignore_state: don't check whether @child is currently %TASK_TRACED
216  *
217  * Check whether @child is being ptraced by %current and ready for further
218  * ptrace operations.  If @ignore_state is %false, @child also should be in
219  * %TASK_TRACED state and on return the child is guaranteed to be traced
220  * and not executing.  If @ignore_state is %true, @child can be in any
221  * state.
222  *
223  * CONTEXT:
224  * Grabs and releases tasklist_lock and @child->sighand->siglock.
225  *
226  * RETURNS:
227  * 0 on success, -ESRCH if %child is not ready.
228  */
229 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
230 {
231         int ret = -ESRCH;
232 
233         /*
234          * We take the read lock around doing both checks to close a
235          * possible race where someone else was tracing our child and
236          * detached between these two checks.  After this locked check,
237          * we are sure that this is our traced child and that can only
238          * be changed by us so it's not changing right after this.
239          */
240         read_lock(&tasklist_lock);
241         if (child->ptrace && child->parent == current) {
242                 WARN_ON(child->state == __TASK_TRACED);
243                 /*
244                  * child->sighand can't be NULL, release_task()
245                  * does ptrace_unlink() before __exit_signal().
246                  */
247                 if (ignore_state || ptrace_freeze_traced(child))
248                         ret = 0;
249         }
250         read_unlock(&tasklist_lock);
251 
252         if (!ret && !ignore_state) {
253                 if (!wait_task_inactive(child, __TASK_TRACED)) {
254                         /*
255                          * This can only happen if may_ptrace_stop() fails and
256                          * ptrace_stop() changes ->state back to TASK_RUNNING,
257                          * so we should not worry about leaking __TASK_TRACED.
258                          */
259                         WARN_ON(child->state == __TASK_TRACED);
260                         ret = -ESRCH;
261                 }
262         }
263 
264         return ret;
265 }
266 
267 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
268 {
269         if (mode & PTRACE_MODE_NOAUDIT)
270                 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
271         else
272                 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
273 }
274 
275 /* Returns 0 on success, -errno on denial. */
276 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
277 {
278         const struct cred *cred = current_cred(), *tcred;
279         struct mm_struct *mm;
280         kuid_t caller_uid;
281         kgid_t caller_gid;
282 
283         if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
284                 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
285                 return -EPERM;
286         }
287 
288         /* May we inspect the given task?
289          * This check is used both for attaching with ptrace
290          * and for allowing access to sensitive information in /proc.
291          *
292          * ptrace_attach denies several cases that /proc allows
293          * because setting up the necessary parent/child relationship
294          * or halting the specified task is impossible.
295          */
296 
297         /* Don't let security modules deny introspection */
298         if (same_thread_group(task, current))
299                 return 0;
300         rcu_read_lock();
301         if (mode & PTRACE_MODE_FSCREDS) {
302                 caller_uid = cred->fsuid;
303                 caller_gid = cred->fsgid;
304         } else {
305                 /*
306                  * Using the euid would make more sense here, but something
307                  * in userland might rely on the old behavior, and this
308                  * shouldn't be a security problem since
309                  * PTRACE_MODE_REALCREDS implies that the caller explicitly
310                  * used a syscall that requests access to another process
311                  * (and not a filesystem syscall to procfs).
312                  */
313                 caller_uid = cred->uid;
314                 caller_gid = cred->gid;
315         }
316         tcred = __task_cred(task);
317         if (uid_eq(caller_uid, tcred->euid) &&
318             uid_eq(caller_uid, tcred->suid) &&
319             uid_eq(caller_uid, tcred->uid)  &&
320             gid_eq(caller_gid, tcred->egid) &&
321             gid_eq(caller_gid, tcred->sgid) &&
322             gid_eq(caller_gid, tcred->gid))
323                 goto ok;
324         if (ptrace_has_cap(tcred->user_ns, mode))
325                 goto ok;
326         rcu_read_unlock();
327         return -EPERM;
328 ok:
329         rcu_read_unlock();
330         /*
331          * If a task drops privileges and becomes nondumpable (through a syscall
332          * like setresuid()) while we are trying to access it, we must ensure
333          * that the dumpability is read after the credentials; otherwise,
334          * we may be able to attach to a task that we shouldn't be able to
335          * attach to (as if the task had dropped privileges without becoming
336          * nondumpable).
337          * Pairs with a write barrier in commit_creds().
338          */
339         smp_rmb();
340         mm = task->mm;
341         if (mm &&
342             ((get_dumpable(mm) != SUID_DUMP_USER) &&
343              !ptrace_has_cap(mm->user_ns, mode)))
344             return -EPERM;
345 
346         return security_ptrace_access_check(task, mode);
347 }
348 
349 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
350 {
351         int err;
352         task_lock(task);
353         err = __ptrace_may_access(task, mode);
354         task_unlock(task);
355         return !err;
356 }
357 
358 static int ptrace_attach(struct task_struct *task, long request,
359                          unsigned long addr,
360                          unsigned long flags)
361 {
362         bool seize = (request == PTRACE_SEIZE);
363         int retval;
364 
365         retval = -EIO;
366         if (seize) {
367                 if (addr != 0)
368                         goto out;
369                 if (flags & ~(unsigned long)PTRACE_O_MASK)
370                         goto out;
371                 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
372         } else {
373                 flags = PT_PTRACED;
374         }
375 
376         audit_ptrace(task);
377 
378         retval = -EPERM;
379         if (unlikely(task->flags & PF_KTHREAD))
380                 goto out;
381         if (same_thread_group(task, current))
382                 goto out;
383 
384         /*
385          * Protect exec's credential calculations against our interference;
386          * SUID, SGID and LSM creds get determined differently
387          * under ptrace.
388          */
389         retval = -ERESTARTNOINTR;
390         if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
391                 goto out;
392 
393         task_lock(task);
394         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
395         task_unlock(task);
396         if (retval)
397                 goto unlock_creds;
398 
399         write_lock_irq(&tasklist_lock);
400         retval = -EPERM;
401         if (unlikely(task->exit_state))
402                 goto unlock_tasklist;
403         if (task->ptrace)
404                 goto unlock_tasklist;
405 
406         if (seize)
407                 flags |= PT_SEIZED;
408         task->ptrace = flags;
409 
410         ptrace_link(task, current);
411 
412         /* SEIZE doesn't trap tracee on attach */
413         if (!seize)
414                 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
415 
416         spin_lock(&task->sighand->siglock);
417 
418         /*
419          * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
420          * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
421          * will be cleared if the child completes the transition or any
422          * event which clears the group stop states happens.  We'll wait
423          * for the transition to complete before returning from this
424          * function.
425          *
426          * This hides STOPPED -> RUNNING -> TRACED transition from the
427          * attaching thread but a different thread in the same group can
428          * still observe the transient RUNNING state.  IOW, if another
429          * thread's WNOHANG wait(2) on the stopped tracee races against
430          * ATTACH, the wait(2) may fail due to the transient RUNNING.
431          *
432          * The following task_is_stopped() test is safe as both transitions
433          * in and out of STOPPED are protected by siglock.
434          */
435         if (task_is_stopped(task) &&
436             task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
437                 signal_wake_up_state(task, __TASK_STOPPED);
438 
439         spin_unlock(&task->sighand->siglock);
440 
441         retval = 0;
442 unlock_tasklist:
443         write_unlock_irq(&tasklist_lock);
444 unlock_creds:
445         mutex_unlock(&task->signal->cred_guard_mutex);
446 out:
447         if (!retval) {
448                 /*
449                  * We do not bother to change retval or clear JOBCTL_TRAPPING
450                  * if wait_on_bit() was interrupted by SIGKILL. The tracer will
451                  * not return to user-mode, it will exit and clear this bit in
452                  * __ptrace_unlink() if it wasn't already cleared by the tracee;
453                  * and until then nobody can ptrace this task.
454                  */
455                 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
456                 proc_ptrace_connector(task, PTRACE_ATTACH);
457         }
458 
459         return retval;
460 }
461 
462 /**
463  * ptrace_traceme  --  helper for PTRACE_TRACEME
464  *
465  * Performs checks and sets PT_PTRACED.
466  * Should be used by all ptrace implementations for PTRACE_TRACEME.
467  */
468 static int ptrace_traceme(void)
469 {
470         int ret = -EPERM;
471 
472         write_lock_irq(&tasklist_lock);
473         /* Are we already being traced? */
474         if (!current->ptrace) {
475                 ret = security_ptrace_traceme(current->parent);
476                 /*
477                  * Check PF_EXITING to ensure ->real_parent has not passed
478                  * exit_ptrace(). Otherwise we don't report the error but
479                  * pretend ->real_parent untraces us right after return.
480                  */
481                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
482                         current->ptrace = PT_PTRACED;
483                         ptrace_link(current, current->real_parent);
484                 }
485         }
486         write_unlock_irq(&tasklist_lock);
487 
488         return ret;
489 }
490 
491 /*
492  * Called with irqs disabled, returns true if childs should reap themselves.
493  */
494 static int ignoring_children(struct sighand_struct *sigh)
495 {
496         int ret;
497         spin_lock(&sigh->siglock);
498         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
499               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
500         spin_unlock(&sigh->siglock);
501         return ret;
502 }
503 
504 /*
505  * Called with tasklist_lock held for writing.
506  * Unlink a traced task, and clean it up if it was a traced zombie.
507  * Return true if it needs to be reaped with release_task().
508  * (We can't call release_task() here because we already hold tasklist_lock.)
509  *
510  * If it's a zombie, our attachedness prevented normal parent notification
511  * or self-reaping.  Do notification now if it would have happened earlier.
512  * If it should reap itself, return true.
513  *
514  * If it's our own child, there is no notification to do. But if our normal
515  * children self-reap, then this child was prevented by ptrace and we must
516  * reap it now, in that case we must also wake up sub-threads sleeping in
517  * do_wait().
518  */
519 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
520 {
521         bool dead;
522 
523         __ptrace_unlink(p);
524 
525         if (p->exit_state != EXIT_ZOMBIE)
526                 return false;
527 
528         dead = !thread_group_leader(p);
529 
530         if (!dead && thread_group_empty(p)) {
531                 if (!same_thread_group(p->real_parent, tracer))
532                         dead = do_notify_parent(p, p->exit_signal);
533                 else if (ignoring_children(tracer->sighand)) {
534                         __wake_up_parent(p, tracer);
535                         dead = true;
536                 }
537         }
538         /* Mark it as in the process of being reaped. */
539         if (dead)
540                 p->exit_state = EXIT_DEAD;
541         return dead;
542 }
543 
544 static int ptrace_detach(struct task_struct *child, unsigned int data)
545 {
546         if (!valid_signal(data))
547                 return -EIO;
548 
549         /* Architecture-specific hardware disable .. */
550         ptrace_disable(child);
551 
552         write_lock_irq(&tasklist_lock);
553         /*
554          * We rely on ptrace_freeze_traced(). It can't be killed and
555          * untraced by another thread, it can't be a zombie.
556          */
557         WARN_ON(!child->ptrace || child->exit_state);
558         /*
559          * tasklist_lock avoids the race with wait_task_stopped(), see
560          * the comment in ptrace_resume().
561          */
562         child->exit_code = data;
563         __ptrace_detach(current, child);
564         write_unlock_irq(&tasklist_lock);
565 
566         proc_ptrace_connector(child, PTRACE_DETACH);
567 
568         return 0;
569 }
570 
571 /*
572  * Detach all tasks we were using ptrace on. Called with tasklist held
573  * for writing.
574  */
575 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
576 {
577         struct task_struct *p, *n;
578 
579         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
580                 if (unlikely(p->ptrace & PT_EXITKILL))
581                         send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
582 
583                 if (__ptrace_detach(tracer, p))
584                         list_add(&p->ptrace_entry, dead);
585         }
586 }
587 
588 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
589 {
590         int copied = 0;
591 
592         while (len > 0) {
593                 char buf[128];
594                 int this_len, retval;
595 
596                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
597                 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
598 
599                 if (!retval) {
600                         if (copied)
601                                 break;
602                         return -EIO;
603                 }
604                 if (copy_to_user(dst, buf, retval))
605                         return -EFAULT;
606                 copied += retval;
607                 src += retval;
608                 dst += retval;
609                 len -= retval;
610         }
611         return copied;
612 }
613 
614 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
615 {
616         int copied = 0;
617 
618         while (len > 0) {
619                 char buf[128];
620                 int this_len, retval;
621 
622                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
623                 if (copy_from_user(buf, src, this_len))
624                         return -EFAULT;
625                 retval = ptrace_access_vm(tsk, dst, buf, this_len,
626                                 FOLL_FORCE | FOLL_WRITE);
627                 if (!retval) {
628                         if (copied)
629                                 break;
630                         return -EIO;
631                 }
632                 copied += retval;
633                 src += retval;
634                 dst += retval;
635                 len -= retval;
636         }
637         return copied;
638 }
639 
640 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
641 {
642         unsigned flags;
643 
644         if (data & ~(unsigned long)PTRACE_O_MASK)
645                 return -EINVAL;
646 
647         if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
648                 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
649                     !IS_ENABLED(CONFIG_SECCOMP))
650                         return -EINVAL;
651 
652                 if (!capable(CAP_SYS_ADMIN))
653                         return -EPERM;
654 
655                 if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
656                     current->ptrace & PT_SUSPEND_SECCOMP)
657                         return -EPERM;
658         }
659 
660         /* Avoid intermediate state when all opts are cleared */
661         flags = child->ptrace;
662         flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
663         flags |= (data << PT_OPT_FLAG_SHIFT);
664         child->ptrace = flags;
665 
666         return 0;
667 }
668 
669 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
670 {
671         unsigned long flags;
672         int error = -ESRCH;
673 
674         if (lock_task_sighand(child, &flags)) {
675                 error = -EINVAL;
676                 if (likely(child->last_siginfo != NULL)) {
677                         copy_siginfo(info, child->last_siginfo);
678                         error = 0;
679                 }
680                 unlock_task_sighand(child, &flags);
681         }
682         return error;
683 }
684 
685 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
686 {
687         unsigned long flags;
688         int error = -ESRCH;
689 
690         if (lock_task_sighand(child, &flags)) {
691                 error = -EINVAL;
692                 if (likely(child->last_siginfo != NULL)) {
693                         copy_siginfo(child->last_siginfo, info);
694                         error = 0;
695                 }
696                 unlock_task_sighand(child, &flags);
697         }
698         return error;
699 }
700 
701 static int ptrace_peek_siginfo(struct task_struct *child,
702                                 unsigned long addr,
703                                 unsigned long data)
704 {
705         struct ptrace_peeksiginfo_args arg;
706         struct sigpending *pending;
707         struct sigqueue *q;
708         int ret, i;
709 
710         ret = copy_from_user(&arg, (void __user *) addr,
711                                 sizeof(struct ptrace_peeksiginfo_args));
712         if (ret)
713                 return -EFAULT;
714 
715         if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
716                 return -EINVAL; /* unknown flags */
717 
718         if (arg.nr < 0)
719                 return -EINVAL;
720 
721         /* Ensure arg.off fits in an unsigned long */
722         if (arg.off > ULONG_MAX)
723                 return 0;
724 
725         if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
726                 pending = &child->signal->shared_pending;
727         else
728                 pending = &child->pending;
729 
730         for (i = 0; i < arg.nr; ) {
731                 kernel_siginfo_t info;
732                 unsigned long off = arg.off + i;
733                 bool found = false;
734 
735                 spin_lock_irq(&child->sighand->siglock);
736                 list_for_each_entry(q, &pending->list, list) {
737                         if (!off--) {
738                                 found = true;
739                                 copy_siginfo(&info, &q->info);
740                                 break;
741                         }
742                 }
743                 spin_unlock_irq(&child->sighand->siglock);
744 
745                 if (!found) /* beyond the end of the list */
746                         break;
747 
748 #ifdef CONFIG_COMPAT
749                 if (unlikely(in_compat_syscall())) {
750                         compat_siginfo_t __user *uinfo = compat_ptr(data);
751 
752                         if (copy_siginfo_to_user32(uinfo, &info)) {
753                                 ret = -EFAULT;
754                                 break;
755                         }
756 
757                 } else
758 #endif
759                 {
760                         siginfo_t __user *uinfo = (siginfo_t __user *) data;
761 
762                         if (copy_siginfo_to_user(uinfo, &info)) {
763                                 ret = -EFAULT;
764                                 break;
765                         }
766                 }
767 
768                 data += sizeof(siginfo_t);
769                 i++;
770 
771                 if (signal_pending(current))
772                         break;
773 
774                 cond_resched();
775         }
776 
777         if (i > 0)
778                 return i;
779 
780         return ret;
781 }
782 
783 #ifdef PTRACE_SINGLESTEP
784 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
785 #else
786 #define is_singlestep(request)          0
787 #endif
788 
789 #ifdef PTRACE_SINGLEBLOCK
790 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
791 #else
792 #define is_singleblock(request)         0
793 #endif
794 
795 #ifdef PTRACE_SYSEMU
796 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
797 #else
798 #define is_sysemu_singlestep(request)   0
799 #endif
800 
801 static int ptrace_resume(struct task_struct *child, long request,
802                          unsigned long data)
803 {
804         bool need_siglock;
805 
806         if (!valid_signal(data))
807                 return -EIO;
808 
809         if (request == PTRACE_SYSCALL)
810                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
811         else
812                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
813 
814 #ifdef TIF_SYSCALL_EMU
815         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
816                 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
817         else
818                 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
819 #endif
820 
821         if (is_singleblock(request)) {
822                 if (unlikely(!arch_has_block_step()))
823                         return -EIO;
824                 user_enable_block_step(child);
825         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
826                 if (unlikely(!arch_has_single_step()))
827                         return -EIO;
828                 user_enable_single_step(child);
829         } else {
830                 user_disable_single_step(child);
831         }
832 
833         /*
834          * Change ->exit_code and ->state under siglock to avoid the race
835          * with wait_task_stopped() in between; a non-zero ->exit_code will
836          * wrongly look like another report from tracee.
837          *
838          * Note that we need siglock even if ->exit_code == data and/or this
839          * status was not reported yet, the new status must not be cleared by
840          * wait_task_stopped() after resume.
841          *
842          * If data == 0 we do not care if wait_task_stopped() reports the old
843          * status and clears the code too; this can't race with the tracee, it
844          * takes siglock after resume.
845          */
846         need_siglock = data && !thread_group_empty(current);
847         if (need_siglock)
848                 spin_lock_irq(&child->sighand->siglock);
849         child->exit_code = data;
850         wake_up_state(child, __TASK_TRACED);
851         if (need_siglock)
852                 spin_unlock_irq(&child->sighand->siglock);
853 
854         return 0;
855 }
856 
857 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
858 
859 static const struct user_regset *
860 find_regset(const struct user_regset_view *view, unsigned int type)
861 {
862         const struct user_regset *regset;
863         int n;
864 
865         for (n = 0; n < view->n; ++n) {
866                 regset = view->regsets + n;
867                 if (regset->core_note_type == type)
868                         return regset;
869         }
870 
871         return NULL;
872 }
873 
874 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
875                          struct iovec *kiov)
876 {
877         const struct user_regset_view *view = task_user_regset_view(task);
878         const struct user_regset *regset = find_regset(view, type);
879         int regset_no;
880 
881         if (!regset || (kiov->iov_len % regset->size) != 0)
882                 return -EINVAL;
883 
884         regset_no = regset - view->regsets;
885         kiov->iov_len = min(kiov->iov_len,
886                             (__kernel_size_t) (regset->n * regset->size));
887 
888         if (req == PTRACE_GETREGSET)
889                 return copy_regset_to_user(task, view, regset_no, 0,
890                                            kiov->iov_len, kiov->iov_base);
891         else
892                 return copy_regset_from_user(task, view, regset_no, 0,
893                                              kiov->iov_len, kiov->iov_base);
894 }
895 
896 /*
897  * This is declared in linux/regset.h and defined in machine-dependent
898  * code.  We put the export here, near the primary machine-neutral use,
899  * to ensure no machine forgets it.
900  */
901 EXPORT_SYMBOL_GPL(task_user_regset_view);
902 
903 static unsigned long
904 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
905                               struct ptrace_syscall_info *info)
906 {
907         unsigned long args[ARRAY_SIZE(info->entry.args)];
908         int i;
909 
910         info->op = PTRACE_SYSCALL_INFO_ENTRY;
911         info->entry.nr = syscall_get_nr(child, regs);
912         syscall_get_arguments(child, regs, args);
913         for (i = 0; i < ARRAY_SIZE(args); i++)
914                 info->entry.args[i] = args[i];
915 
916         /* args is the last field in struct ptrace_syscall_info.entry */
917         return offsetofend(struct ptrace_syscall_info, entry.args);
918 }
919 
920 static unsigned long
921 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
922                                 struct ptrace_syscall_info *info)
923 {
924         /*
925          * As struct ptrace_syscall_info.entry is currently a subset
926          * of struct ptrace_syscall_info.seccomp, it makes sense to
927          * initialize that subset using ptrace_get_syscall_info_entry().
928          * This can be reconsidered in the future if these structures
929          * diverge significantly enough.
930          */
931         ptrace_get_syscall_info_entry(child, regs, info);
932         info->op = PTRACE_SYSCALL_INFO_SECCOMP;
933         info->seccomp.ret_data = child->ptrace_message;
934 
935         /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
936         return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
937 }
938 
939 static unsigned long
940 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
941                              struct ptrace_syscall_info *info)
942 {
943         info->op = PTRACE_SYSCALL_INFO_EXIT;
944         info->exit.rval = syscall_get_error(child, regs);
945         info->exit.is_error = !!info->exit.rval;
946         if (!info->exit.is_error)
947                 info->exit.rval = syscall_get_return_value(child, regs);
948 
949         /* is_error is the last field in struct ptrace_syscall_info.exit */
950         return offsetofend(struct ptrace_syscall_info, exit.is_error);
951 }
952 
953 static int
954 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
955                         void __user *datavp)
956 {
957         struct pt_regs *regs = task_pt_regs(child);
958         struct ptrace_syscall_info info = {
959                 .op = PTRACE_SYSCALL_INFO_NONE,
960                 .arch = syscall_get_arch(child),
961                 .instruction_pointer = instruction_pointer(regs),
962                 .stack_pointer = user_stack_pointer(regs),
963         };
964         unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
965         unsigned long write_size;
966 
967         /*
968          * This does not need lock_task_sighand() to access
969          * child->last_siginfo because ptrace_freeze_traced()
970          * called earlier by ptrace_check_attach() ensures that
971          * the tracee cannot go away and clear its last_siginfo.
972          */
973         switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
974         case SIGTRAP | 0x80:
975                 switch (child->ptrace_message) {
976                 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
977                         actual_size = ptrace_get_syscall_info_entry(child, regs,
978                                                                     &info);
979                         break;
980                 case PTRACE_EVENTMSG_SYSCALL_EXIT:
981                         actual_size = ptrace_get_syscall_info_exit(child, regs,
982                                                                    &info);
983                         break;
984                 }
985                 break;
986         case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
987                 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
988                                                               &info);
989                 break;
990         }
991 
992         write_size = min(actual_size, user_size);
993         return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
994 }
995 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
996 
997 int ptrace_request(struct task_struct *child, long request,
998                    unsigned long addr, unsigned long data)
999 {
1000         bool seized = child->ptrace & PT_SEIZED;
1001         int ret = -EIO;
1002         kernel_siginfo_t siginfo, *si;
1003         void __user *datavp = (void __user *) data;
1004         unsigned long __user *datalp = datavp;
1005         unsigned long flags;
1006 
1007         switch (request) {
1008         case PTRACE_PEEKTEXT:
1009         case PTRACE_PEEKDATA:
1010                 return generic_ptrace_peekdata(child, addr, data);
1011         case PTRACE_POKETEXT:
1012         case PTRACE_POKEDATA:
1013                 return generic_ptrace_pokedata(child, addr, data);
1014 
1015 #ifdef PTRACE_OLDSETOPTIONS
1016         case PTRACE_OLDSETOPTIONS:
1017 #endif
1018         case PTRACE_SETOPTIONS:
1019                 ret = ptrace_setoptions(child, data);
1020                 break;
1021         case PTRACE_GETEVENTMSG:
1022                 ret = put_user(child->ptrace_message, datalp);
1023                 break;
1024 
1025         case PTRACE_PEEKSIGINFO:
1026                 ret = ptrace_peek_siginfo(child, addr, data);
1027                 break;
1028 
1029         case PTRACE_GETSIGINFO:
1030                 ret = ptrace_getsiginfo(child, &siginfo);
1031                 if (!ret)
1032                         ret = copy_siginfo_to_user(datavp, &siginfo);
1033                 break;
1034 
1035         case PTRACE_SETSIGINFO:
1036                 ret = copy_siginfo_from_user(&siginfo, datavp);
1037                 if (!ret)
1038                         ret = ptrace_setsiginfo(child, &siginfo);
1039                 break;
1040 
1041         case PTRACE_GETSIGMASK: {
1042                 sigset_t *mask;
1043 
1044                 if (addr != sizeof(sigset_t)) {
1045                         ret = -EINVAL;
1046                         break;
1047                 }
1048 
1049                 if (test_tsk_restore_sigmask(child))
1050                         mask = &child->saved_sigmask;
1051                 else
1052                         mask = &child->blocked;
1053 
1054                 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
1055                         ret = -EFAULT;
1056                 else
1057                         ret = 0;
1058 
1059                 break;
1060         }
1061 
1062         case PTRACE_SETSIGMASK: {
1063                 sigset_t new_set;
1064 
1065                 if (addr != sizeof(sigset_t)) {
1066                         ret = -EINVAL;
1067                         break;
1068                 }
1069 
1070                 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1071                         ret = -EFAULT;
1072                         break;
1073                 }
1074 
1075                 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1076 
1077                 /*
1078                  * Every thread does recalc_sigpending() after resume, so
1079                  * retarget_shared_pending() and recalc_sigpending() are not
1080                  * called here.
1081                  */
1082                 spin_lock_irq(&child->sighand->siglock);
1083                 child->blocked = new_set;
1084                 spin_unlock_irq(&child->sighand->siglock);
1085 
1086                 clear_tsk_restore_sigmask(child);
1087 
1088                 ret = 0;
1089                 break;
1090         }
1091 
1092         case PTRACE_INTERRUPT:
1093                 /*
1094                  * Stop tracee without any side-effect on signal or job
1095                  * control.  At least one trap is guaranteed to happen
1096                  * after this request.  If @child is already trapped, the
1097                  * current trap is not disturbed and another trap will
1098                  * happen after the current trap is ended with PTRACE_CONT.
1099                  *
1100                  * The actual trap might not be PTRACE_EVENT_STOP trap but
1101                  * the pending condition is cleared regardless.
1102                  */
1103                 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1104                         break;
1105 
1106                 /*
1107                  * INTERRUPT doesn't disturb existing trap sans one
1108                  * exception.  If ptracer issued LISTEN for the current
1109                  * STOP, this INTERRUPT should clear LISTEN and re-trap
1110                  * tracee into STOP.
1111                  */
1112                 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
1113                         ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
1114 
1115                 unlock_task_sighand(child, &flags);
1116                 ret = 0;
1117                 break;
1118 
1119         case PTRACE_LISTEN:
1120                 /*
1121                  * Listen for events.  Tracee must be in STOP.  It's not
1122                  * resumed per-se but is not considered to be in TRACED by
1123                  * wait(2) or ptrace(2).  If an async event (e.g. group
1124                  * stop state change) happens, tracee will enter STOP trap
1125                  * again.  Alternatively, ptracer can issue INTERRUPT to
1126                  * finish listening and re-trap tracee into STOP.
1127                  */
1128                 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1129                         break;
1130 
1131                 si = child->last_siginfo;
1132                 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1133                         child->jobctl |= JOBCTL_LISTENING;
1134                         /*
1135                          * If NOTIFY is set, it means event happened between
1136                          * start of this trap and now.  Trigger re-trap.
1137                          */
1138                         if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1139                                 ptrace_signal_wake_up(child, true);
1140                         ret = 0;
1141                 }
1142                 unlock_task_sighand(child, &flags);
1143                 break;
1144 
1145         case PTRACE_DETACH:      /* detach a process that was attached. */
1146                 ret = ptrace_detach(child, data);
1147                 break;
1148 
1149 #ifdef CONFIG_BINFMT_ELF_FDPIC
1150         case PTRACE_GETFDPIC: {
1151                 struct mm_struct *mm = get_task_mm(child);
1152                 unsigned long tmp = 0;
1153 
1154                 ret = -ESRCH;
1155                 if (!mm)
1156                         break;
1157 
1158                 switch (addr) {
1159                 case PTRACE_GETFDPIC_EXEC:
1160                         tmp = mm->context.exec_fdpic_loadmap;
1161                         break;
1162                 case PTRACE_GETFDPIC_INTERP:
1163                         tmp = mm->context.interp_fdpic_loadmap;
1164                         break;
1165                 default:
1166                         break;
1167                 }
1168                 mmput(mm);
1169 
1170                 ret = put_user(tmp, datalp);
1171                 break;
1172         }
1173 #endif
1174 
1175 #ifdef PTRACE_SINGLESTEP
1176         case PTRACE_SINGLESTEP:
1177 #endif
1178 #ifdef PTRACE_SINGLEBLOCK
1179         case PTRACE_SINGLEBLOCK:
1180 #endif
1181 #ifdef PTRACE_SYSEMU
1182         case PTRACE_SYSEMU:
1183         case PTRACE_SYSEMU_SINGLESTEP:
1184 #endif
1185         case PTRACE_SYSCALL:
1186         case PTRACE_CONT:
1187                 return ptrace_resume(child, request, data);
1188 
1189         case PTRACE_KILL:
1190                 if (child->exit_state)  /* already dead */
1191                         return 0;
1192                 return ptrace_resume(child, request, SIGKILL);
1193 
1194 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1195         case PTRACE_GETREGSET:
1196         case PTRACE_SETREGSET: {
1197                 struct iovec kiov;
1198                 struct iovec __user *uiov = datavp;
1199 
1200                 if (!access_ok(uiov, sizeof(*uiov)))
1201                         return -EFAULT;
1202 
1203                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1204                     __get_user(kiov.iov_len, &uiov->iov_len))
1205                         return -EFAULT;
1206 
1207                 ret = ptrace_regset(child, request, addr, &kiov);
1208                 if (!ret)
1209                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
1210                 break;
1211         }
1212 
1213         case PTRACE_GET_SYSCALL_INFO:
1214                 ret = ptrace_get_syscall_info(child, addr, datavp);
1215                 break;
1216 #endif
1217 
1218         case PTRACE_SECCOMP_GET_FILTER:
1219                 ret = seccomp_get_filter(child, addr, datavp);
1220                 break;
1221 
1222         case PTRACE_SECCOMP_GET_METADATA:
1223                 ret = seccomp_get_metadata(child, addr, datavp);
1224                 break;
1225 
1226         default:
1227                 break;
1228         }
1229 
1230         return ret;
1231 }
1232 
1233 #ifndef arch_ptrace_attach
1234 #define arch_ptrace_attach(child)       do { } while (0)
1235 #endif
1236 
1237 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1238                 unsigned long, data)
1239 {
1240         struct task_struct *child;
1241         long ret;
1242         {
1243                 const int rc = ccs_ptrace_permission(request, pid);
1244                 if (rc)
1245                         return rc;
1246         }
1247 
1248         if (request == PTRACE_TRACEME) {
1249                 ret = ptrace_traceme();
1250                 if (!ret)
1251                         arch_ptrace_attach(current);
1252                 goto out;
1253         }
1254 
1255         child = find_get_task_by_vpid(pid);
1256         if (!child) {
1257                 ret = -ESRCH;
1258                 goto out;
1259         }
1260 
1261         if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1262                 ret = ptrace_attach(child, request, addr, data);
1263                 /*
1264                  * Some architectures need to do book-keeping after
1265                  * a ptrace attach.
1266                  */
1267                 if (!ret)
1268                         arch_ptrace_attach(child);
1269                 goto out_put_task_struct;
1270         }
1271 
1272         ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1273                                   request == PTRACE_INTERRUPT);
1274         if (ret < 0)
1275                 goto out_put_task_struct;
1276 
1277         ret = arch_ptrace(child, request, addr, data);
1278         if (ret || request != PTRACE_DETACH)
1279                 ptrace_unfreeze_traced(child);
1280 
1281  out_put_task_struct:
1282         put_task_struct(child);
1283  out:
1284         return ret;
1285 }
1286 
1287 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1288                             unsigned long data)
1289 {
1290         unsigned long tmp;
1291         int copied;
1292 
1293         copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1294         if (copied != sizeof(tmp))
1295                 return -EIO;
1296         return put_user(tmp, (unsigned long __user *)data);
1297 }
1298 
1299 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1300                             unsigned long data)
1301 {
1302         int copied;
1303 
1304         copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1305                         FOLL_FORCE | FOLL_WRITE);
1306         return (copied == sizeof(data)) ? 0 : -EIO;
1307 }
1308 
1309 #if defined CONFIG_COMPAT
1310 
1311 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1312                           compat_ulong_t addr, compat_ulong_t data)
1313 {
1314         compat_ulong_t __user *datap = compat_ptr(data);
1315         compat_ulong_t word;
1316         kernel_siginfo_t siginfo;
1317         int ret;
1318 
1319         switch (request) {
1320         case PTRACE_PEEKTEXT:
1321         case PTRACE_PEEKDATA:
1322                 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1323                                 FOLL_FORCE);
1324                 if (ret != sizeof(word))
1325                         ret = -EIO;
1326                 else
1327                         ret = put_user(word, datap);
1328                 break;
1329 
1330         case PTRACE_POKETEXT:
1331         case PTRACE_POKEDATA:
1332                 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1333                                 FOLL_FORCE | FOLL_WRITE);
1334                 ret = (ret != sizeof(data) ? -EIO : 0);
1335                 break;
1336 
1337         case PTRACE_GETEVENTMSG:
1338                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1339                 break;
1340 
1341         case PTRACE_GETSIGINFO:
1342                 ret = ptrace_getsiginfo(child, &siginfo);
1343                 if (!ret)
1344                         ret = copy_siginfo_to_user32(
1345                                 (struct compat_siginfo __user *) datap,
1346                                 &siginfo);
1347                 break;
1348 
1349         case PTRACE_SETSIGINFO:
1350                 ret = copy_siginfo_from_user32(
1351                         &siginfo, (struct compat_siginfo __user *) datap);
1352                 if (!ret)
1353                         ret = ptrace_setsiginfo(child, &siginfo);
1354                 break;
1355 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1356         case PTRACE_GETREGSET:
1357         case PTRACE_SETREGSET:
1358         {
1359                 struct iovec kiov;
1360                 struct compat_iovec __user *uiov =
1361                         (struct compat_iovec __user *) datap;
1362                 compat_uptr_t ptr;
1363                 compat_size_t len;
1364 
1365                 if (!access_ok(uiov, sizeof(*uiov)))
1366                         return -EFAULT;
1367 
1368                 if (__get_user(ptr, &uiov->iov_base) ||
1369                     __get_user(len, &uiov->iov_len))
1370                         return -EFAULT;
1371 
1372                 kiov.iov_base = compat_ptr(ptr);
1373                 kiov.iov_len = len;
1374 
1375                 ret = ptrace_regset(child, request, addr, &kiov);
1376                 if (!ret)
1377                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
1378                 break;
1379         }
1380 #endif
1381 
1382         default:
1383                 ret = ptrace_request(child, request, addr, data);
1384         }
1385 
1386         return ret;
1387 }
1388 
1389 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1390                        compat_long_t, addr, compat_long_t, data)
1391 {
1392         struct task_struct *child;
1393         long ret;
1394         {
1395                 const int rc = ccs_ptrace_permission(request, pid);
1396                 if (rc)
1397                         return rc;
1398         }
1399 
1400         if (request == PTRACE_TRACEME) {
1401                 ret = ptrace_traceme();
1402                 goto out;
1403         }
1404 
1405         child = find_get_task_by_vpid(pid);
1406         if (!child) {
1407                 ret = -ESRCH;
1408                 goto out;
1409         }
1410 
1411         if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1412                 ret = ptrace_attach(child, request, addr, data);
1413                 /*
1414                  * Some architectures need to do book-keeping after
1415                  * a ptrace attach.
1416                  */
1417                 if (!ret)
1418                         arch_ptrace_attach(child);
1419                 goto out_put_task_struct;
1420         }
1421 
1422         ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1423                                   request == PTRACE_INTERRUPT);
1424         if (!ret) {
1425                 ret = compat_arch_ptrace(child, request, addr, data);
1426                 if (ret || request != PTRACE_DETACH)
1427                         ptrace_unfreeze_traced(child);
1428         }
1429 
1430  out_put_task_struct:
1431         put_task_struct(child);
1432  out:
1433         return ret;
1434 }
1435 #endif  /* CONFIG_COMPAT */
1436 

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