root/kernel/ptrace.c

DEFINITIONS

1. ptrace_access_vm
2. __ptrace_link
3. ptrace_link
4. __ptrace_unlink
5. ptrace_freeze_traced
6. ptrace_unfreeze_traced
7. ptrace_check_attach
8. ptrace_has_cap
9. __ptrace_may_access
10. ptrace_may_access
11. ptrace_attach
12. ptrace_traceme
13. ignoring_children
14. __ptrace_detach
15. ptrace_detach
16. exit_ptrace
17. ptrace_readdata
18. ptrace_writedata
19. ptrace_setoptions
20. ptrace_getsiginfo
21. ptrace_setsiginfo
22. ptrace_peek_siginfo
23. ptrace_resume
24. find_regset
25. ptrace_regset
26. ptrace_get_syscall_info_entry
27. ptrace_get_syscall_info_seccomp
28. ptrace_get_syscall_info_exit
29. ptrace_get_syscall_info
30. ptrace_request
31. SYSCALL_DEFINE4
32. generic_ptrace_peekdata
33. generic_ptrace_pokedata
34. compat_ptrace_request
35. COMPAT_SYSCALL_DEFINE4

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