kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/kernel/ptrace.c
   4  *
   5  * (C) Copyright 1999 Linus Torvalds
   6  *
   7  * Common interfaces for "ptrace()" which we do not want
   8  * to continually duplicate across every architecture.
   9  */
  10
  11 #include <linux/capability.h>
  12 #include <linux/export.h>
  13 #include <linux/sched.h>
  14 #include <linux/sched/mm.h>
  15 #include <linux/sched/coredump.h>
  16 #include <linux/sched/task.h>
  17 #include <linux/errno.h>
  18 #include <linux/mm.h>
  19 #include <linux/highmem.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/security.h>
  23 #include <linux/signal.h>
  24 #include <linux/uio.h>
  25 #include <linux/audit.h>
  26 #include <linux/pid_namespace.h>
  27 #include <linux/syscalls.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/regset.h>
  30 #include <linux/hw_breakpoint.h>
  31 #include <linux/cn_proc.h>
  32 #include <linux/compat.h>
  33 #include <linux/sched/signal.h>
  34 #include <linux/minmax.h>
  35
  36 #include <asm/syscall.h>        /* for syscall_get_* */
  37
  38 /*
  39  * Access another process' address space via ptrace.
  40  * Source/target buffer must be kernel space,
  41  * Do not walk the page table directly, use get_user_pages
  42  */
  43 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
  44                      void *buf, int len, unsigned int gup_flags)
  45 {
  46         struct mm_struct *mm;
  47         int ret;
  48
  49         mm = get_task_mm(tsk);
  50         if (!mm)
  51                 return 0;
  52
  53         if (!tsk->ptrace ||
  54             (current != tsk->parent) ||
  55             ((get_dumpable(mm) != SUID_DUMP_USER) &&
  56              !ptracer_capable(tsk, mm->user_ns))) {
  57                 mmput(mm);
  58                 return 0;
  59         }
  60
  61         ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
  62         mmput(mm);
  63
  64         return ret;
  65 }
  66
  67
  68 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
  69                    const struct cred *ptracer_cred)
  70 {
  71         BUG_ON(!list_empty(&child->ptrace_entry));
  72         list_add(&child->ptrace_entry, &new_parent->ptraced);
  73         child->parent = new_parent;
  74         child->ptracer_cred = get_cred(ptracer_cred);
  75 }
  76
  77 /*
  78  * ptrace a task: make the debugger its new parent and
  79  * move it to the ptrace list.
  80  *
  81  * Must be called with the tasklist lock write-held.
  82  */
  83 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
  84 {
  85         __ptrace_link(child, new_parent, current_cred());
  86 }
  87
  88 /**
  89  * __ptrace_unlink - unlink ptracee and restore its execution state
  90  * @child: ptracee to be unlinked
  91  *
  92  * Remove @child from the ptrace list, move it back to the original parent,
  93  * and restore the execution state so that it conforms to the group stop
  94  * state.
  95  *
  96  * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
  97  * exiting.  For PTRACE_DETACH, unless the ptracee has been killed between
  98  * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
  99  * If the ptracer is exiting, the ptracee can be in any state.
 100  *
 101  * After detach, the ptracee should be in a state which conforms to the
 102  * group stop.  If the group is stopped or in the process of stopping, the
 103  * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
 104  * up from TASK_TRACED.
 105  *
 106  * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
 107  * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
 108  * to but in the opposite direction of what happens while attaching to a
 109  * stopped task.  However, in this direction, the intermediate RUNNING
 110  * state is not hidden even from the current ptracer and if it immediately
 111  * re-attaches and performs a WNOHANG wait(2), it may fail.
 112  *
 113  * CONTEXT:
 114  * write_lock_irq(tasklist_lock)
 115  */
 116 void __ptrace_unlink(struct task_struct *child)
 117 {
 118         const struct cred *old_cred;
 119         BUG_ON(!child->ptrace);
 120
 121         clear_task_syscall_work(child, SYSCALL_TRACE);
 122 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
 123         clear_task_syscall_work(child, SYSCALL_EMU);
 124 #endif
 125
 126         child->parent = child->real_parent;
 127         list_del_init(&child->ptrace_entry);
 128         old_cred = child->ptracer_cred;
 129         child->ptracer_cred = NULL;
 130         put_cred(old_cred);
 131
 132         spin_lock(&child->sighand->siglock);
 133         child->ptrace = 0;
 134         /*
 135          * Clear all pending traps and TRAPPING.  TRAPPING should be
 136          * cleared regardless of JOBCTL_STOP_PENDING.  Do it explicitly.
 137          */
 138         task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
 139         task_clear_jobctl_trapping(child);
 140
 141         /*
 142          * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
 143          * @child isn't dead.
 144          */
 145         if (!(child->flags & PF_EXITING) &&
 146             (child->signal->flags & SIGNAL_STOP_STOPPED ||
 147              child->signal->group_stop_count)) {
 148                 child->jobctl |= JOBCTL_STOP_PENDING;
 149
 150                 /*
 151                  * This is only possible if this thread was cloned by the
 152                  * traced task running in the stopped group, set the signal
 153                  * for the future reports.
 154                  * FIXME: we should change ptrace_init_task() to handle this
 155                  * case.
 156                  */
 157                 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
 158                         child->jobctl |= SIGSTOP;
 159         }
 160
 161         /*
 162          * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
 163          * @child in the butt.  Note that @resume should be used iff @child
 164          * is in TASK_TRACED; otherwise, we might unduly disrupt
 165          * TASK_KILLABLE sleeps.
 166          */
 167         if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
 168                 ptrace_signal_wake_up(child, true);
 169
 170         spin_unlock(&child->sighand->siglock);
 171 }
 172
 173 static bool looks_like_a_spurious_pid(struct task_struct *task)
 174 {
 175         if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
 176                 return false;
 177
 178         if (task_pid_vnr(task) == task->ptrace_message)
 179                 return false;
 180         /*
 181          * The tracee changed its pid but the PTRACE_EVENT_EXEC event
 182          * was not wait()'ed, most probably debugger targets the old
 183          * leader which was destroyed in de_thread().
 184          */
 185         return true;
 186 }
 187
 188 /* Ensure that nothing can wake it up, even SIGKILL */
 189 static bool ptrace_freeze_traced(struct task_struct *task)
 190 {
 191         bool ret = false;
 192
 193         /* Lockless, nobody but us can set this flag */
 194         if (task->jobctl & JOBCTL_LISTENING)
 195                 return ret;
 196
 197         spin_lock_irq(&task->sighand->siglock);
 198         if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
 199             !__fatal_signal_pending(task)) {
 200                 WRITE_ONCE(task->__state, __TASK_TRACED);
 201                 ret = true;
 202         }
 203         spin_unlock_irq(&task->sighand->siglock);
 204
 205         return ret;
 206 }
 207
 208 static void ptrace_unfreeze_traced(struct task_struct *task)
 209 {
 210         if (READ_ONCE(task->__state) != __TASK_TRACED)
 211                 return;
 212
 213         WARN_ON(!task->ptrace || task->parent != current);
 214
 215         /*
 216          * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
 217          * Recheck state under the lock to close this race.
 218          */
 219         spin_lock_irq(&task->sighand->siglock);
 220         if (READ_ONCE(task->__state) == __TASK_TRACED) {
 221                 if (__fatal_signal_pending(task))
 222                         wake_up_state(task, __TASK_TRACED);
 223                 else
 224                         WRITE_ONCE(task->__state, TASK_TRACED);
 225         }
 226         spin_unlock_irq(&task->sighand->siglock);
 227 }
 228
 229 /**
 230  * ptrace_check_attach - check whether ptracee is ready for ptrace operation
 231  * @child: ptracee to check for
 232  * @ignore_state: don't check whether @child is currently %TASK_TRACED
 233  *
 234  * Check whether @child is being ptraced by %current and ready for further
 235  * ptrace operations.  If @ignore_state is %false, @child also should be in
 236  * %TASK_TRACED state and on return the child is guaranteed to be traced
 237  * and not executing.  If @ignore_state is %true, @child can be in any
 238  * state.
 239  *
 240  * CONTEXT:
 241  * Grabs and releases tasklist_lock and @child->sighand->siglock.
 242  *
 243  * RETURNS:
 244  * 0 on success, -ESRCH if %child is not ready.
 245  */
 246 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
 247 {
 248         int ret = -ESRCH;
 249
 250         /*
 251          * We take the read lock around doing both checks to close a
 252          * possible race where someone else was tracing our child and
 253          * detached between these two checks.  After this locked check,
 254          * we are sure that this is our traced child and that can only
 255          * be changed by us so it's not changing right after this.
 256          */
 257         read_lock(&tasklist_lock);
 258         if (child->ptrace && child->parent == current) {
 259                 WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED);
 260                 /*
 261                  * child->sighand can't be NULL, release_task()
 262                  * does ptrace_unlink() before __exit_signal().
 263                  */
 264                 if (ignore_state || ptrace_freeze_traced(child))
 265                         ret = 0;
 266         }
 267         read_unlock(&tasklist_lock);
 268
 269         if (!ret && !ignore_state) {
 270                 if (!wait_task_inactive(child, __TASK_TRACED)) {
 271                         /*
 272                          * This can only happen if may_ptrace_stop() fails and
 273                          * ptrace_stop() changes ->state back to TASK_RUNNING,
 274                          * so we should not worry about leaking __TASK_TRACED.
 275                          */
 276                         WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED);
 277                         ret = -ESRCH;
 278                 }
 279         }
 280
 281         return ret;
 282 }
 283
 284 static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
 285 {
 286         if (mode & PTRACE_MODE_NOAUDIT)
 287                 return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
 288         return ns_capable(ns, CAP_SYS_PTRACE);
 289 }
 290
 291 /* Returns 0 on success, -errno on denial. */
 292 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 293 {
 294         const struct cred *cred = current_cred(), *tcred;
 295         struct mm_struct *mm;
 296         kuid_t caller_uid;
 297         kgid_t caller_gid;
 298
 299         if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
 300                 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
 301                 return -EPERM;
 302         }
 303
 304         /* May we inspect the given task?
 305          * This check is used both for attaching with ptrace
 306          * and for allowing access to sensitive information in /proc.
 307          *
 308          * ptrace_attach denies several cases that /proc allows
 309          * because setting up the necessary parent/child relationship
 310          * or halting the specified task is impossible.
 311          */
 312
 313         /* Don't let security modules deny introspection */
 314         if (same_thread_group(task, current))
 315                 return 0;
 316         rcu_read_lock();
 317         if (mode & PTRACE_MODE_FSCREDS) {
 318                 caller_uid = cred->fsuid;
 319                 caller_gid = cred->fsgid;
 320         } else {
 321                 /*
 322                  * Using the euid would make more sense here, but something
 323                  * in userland might rely on the old behavior, and this
 324                  * shouldn't be a security problem since
 325                  * PTRACE_MODE_REALCREDS implies that the caller explicitly
 326                  * used a syscall that requests access to another process
 327                  * (and not a filesystem syscall to procfs).
 328                  */
 329                 caller_uid = cred->uid;
 330                 caller_gid = cred->gid;
 331         }
 332         tcred = __task_cred(task);
 333         if (uid_eq(caller_uid, tcred->euid) &&
 334             uid_eq(caller_uid, tcred->suid) &&
 335             uid_eq(caller_uid, tcred->uid)  &&
 336             gid_eq(caller_gid, tcred->egid) &&
 337             gid_eq(caller_gid, tcred->sgid) &&
 338             gid_eq(caller_gid, tcred->gid))
 339                 goto ok;
 340         if (ptrace_has_cap(tcred->user_ns, mode))
 341                 goto ok;
 342         rcu_read_unlock();
 343         return -EPERM;
 344 ok:
 345         rcu_read_unlock();
 346         /*
 347          * If a task drops privileges and becomes nondumpable (through a syscall
 348          * like setresuid()) while we are trying to access it, we must ensure
 349          * that the dumpability is read after the credentials; otherwise,
 350          * we may be able to attach to a task that we shouldn't be able to
 351          * attach to (as if the task had dropped privileges without becoming
 352          * nondumpable).
 353          * Pairs with a write barrier in commit_creds().
 354          */
 355         smp_rmb();
 356         mm = task->mm;
 357         if (mm &&
 358             ((get_dumpable(mm) != SUID_DUMP_USER) &&
 359              !ptrace_has_cap(mm->user_ns, mode)))
 360             return -EPERM;
 361
 362         return security_ptrace_access_check(task, mode);
 363 }
 364
 365 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
 366 {
 367         int err;
 368         task_lock(task);
 369         err = __ptrace_may_access(task, mode);
 370         task_unlock(task);
 371         return !err;
 372 }
 373
 374 static int ptrace_attach(struct task_struct *task, long request,
 375                          unsigned long addr,
 376                          unsigned long flags)
 377 {
 378         bool seize = (request == PTRACE_SEIZE);
 379         int retval;
 380
 381         retval = -EIO;
 382         if (seize) {
 383                 if (addr != 0)
 384                         goto out;
 385                 if (flags & ~(unsigned long)PTRACE_O_MASK)
 386                         goto out;
 387                 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
 388         } else {
 389                 flags = PT_PTRACED;
 390         }
 391
 392         audit_ptrace(task);
 393
 394         retval = -EPERM;
 395         if (unlikely(task->flags & PF_KTHREAD))
 396                 goto out;
 397         if (same_thread_group(task, current))
 398                 goto out;
 399
 400         /*
 401          * Protect exec's credential calculations against our interference;
 402          * SUID, SGID and LSM creds get determined differently
 403          * under ptrace.
 404          */
 405         retval = -ERESTARTNOINTR;
 406         if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
 407                 goto out;
 408
 409         task_lock(task);
 410         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
 411         task_unlock(task);
 412         if (retval)
 413                 goto unlock_creds;
 414
 415         write_lock_irq(&tasklist_lock);
 416         retval = -EPERM;
 417         if (unlikely(task->exit_state))
 418                 goto unlock_tasklist;
 419         if (task->ptrace)
 420                 goto unlock_tasklist;
 421
 422         if (seize)
 423                 flags |= PT_SEIZED;
 424         task->ptrace = flags;
 425
 426         ptrace_link(task, current);
 427
 428         /* SEIZE doesn't trap tracee on attach */
 429         if (!seize)
 430                 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
 431
 432         spin_lock(&task->sighand->siglock);
 433
 434         /*
 435          * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
 436          * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
 437          * will be cleared if the child completes the transition or any
 438          * event which clears the group stop states happens.  We'll wait
 439          * for the transition to complete before returning from this
 440          * function.
 441          *
 442          * This hides STOPPED -> RUNNING -> TRACED transition from the
 443          * attaching thread but a different thread in the same group can
 444          * still observe the transient RUNNING state.  IOW, if another
 445          * thread's WNOHANG wait(2) on the stopped tracee races against
 446          * ATTACH, the wait(2) may fail due to the transient RUNNING.
 447          *
 448          * The following task_is_stopped() test is safe as both transitions
 449          * in and out of STOPPED are protected by siglock.
 450          */
 451         if (task_is_stopped(task) &&
 452             task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
 453                 signal_wake_up_state(task, __TASK_STOPPED);
 454
 455         spin_unlock(&task->sighand->siglock);
 456
 457         retval = 0;
 458 unlock_tasklist:
 459         write_unlock_irq(&tasklist_lock);
 460 unlock_creds:
 461         mutex_unlock(&task->signal->cred_guard_mutex);
 462 out:
 463         if (!retval) {
 464                 /*
 465                  * We do not bother to change retval or clear JOBCTL_TRAPPING
 466                  * if wait_on_bit() was interrupted by SIGKILL. The tracer will
 467                  * not return to user-mode, it will exit and clear this bit in
 468                  * __ptrace_unlink() if it wasn't already cleared by the tracee;
 469                  * and until then nobody can ptrace this task.
 470                  */
 471                 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
 472                 proc_ptrace_connector(task, PTRACE_ATTACH);
 473         }
 474
 475         return retval;
 476 }
 477
 478 /**
 479  * ptrace_traceme  --  helper for PTRACE_TRACEME
 480  *
 481  * Performs checks and sets PT_PTRACED.
 482  * Should be used by all ptrace implementations for PTRACE_TRACEME.
 483  */
 484 static int ptrace_traceme(void)
 485 {
 486         int ret = -EPERM;
 487
 488         write_lock_irq(&tasklist_lock);
 489         /* Are we already being traced? */
 490         if (!current->ptrace) {
 491                 ret = security_ptrace_traceme(current->parent);
 492                 /*
 493                  * Check PF_EXITING to ensure ->real_parent has not passed
 494                  * exit_ptrace(). Otherwise we don't report the error but
 495                  * pretend ->real_parent untraces us right after return.
 496                  */
 497                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
 498                         current->ptrace = PT_PTRACED;
 499                         ptrace_link(current, current->real_parent);
 500                 }
 501         }
 502         write_unlock_irq(&tasklist_lock);
 503
 504         return ret;
 505 }
 506
 507 /*
 508  * Called with irqs disabled, returns true if childs should reap themselves.
 509  */
 510 static int ignoring_children(struct sighand_struct *sigh)
 511 {
 512         int ret;
 513         spin_lock(&sigh->siglock);
 514         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
 515               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
 516         spin_unlock(&sigh->siglock);
 517         return ret;
 518 }
 519
 520 /*
 521  * Called with tasklist_lock held for writing.
 522  * Unlink a traced task, and clean it up if it was a traced zombie.
 523  * Return true if it needs to be reaped with release_task().
 524  * (We can't call release_task() here because we already hold tasklist_lock.)
 525  *
 526  * If it's a zombie, our attachedness prevented normal parent notification
 527  * or self-reaping.  Do notification now if it would have happened earlier.
 528  * If it should reap itself, return true.
 529  *
 530  * If it's our own child, there is no notification to do. But if our normal
 531  * children self-reap, then this child was prevented by ptrace and we must
 532  * reap it now, in that case we must also wake up sub-threads sleeping in
 533  * do_wait().
 534  */
 535 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
 536 {
 537         bool dead;
 538
 539         __ptrace_unlink(p);
 540
 541         if (p->exit_state != EXIT_ZOMBIE)
 542                 return false;
 543
 544         dead = !thread_group_leader(p);
 545
 546         if (!dead && thread_group_empty(p)) {
 547                 if (!same_thread_group(p->real_parent, tracer))
 548                         dead = do_notify_parent(p, p->exit_signal);
 549                 else if (ignoring_children(tracer->sighand)) {
 550                         __wake_up_parent(p, tracer);
 551                         dead = true;
 552                 }
 553         }
 554         /* Mark it as in the process of being reaped. */
 555         if (dead)
 556                 p->exit_state = EXIT_DEAD;
 557         return dead;
 558 }
 559
 560 static int ptrace_detach(struct task_struct *child, unsigned int data)
 561 {
 562         if (!valid_signal(data))
 563                 return -EIO;
 564
 565         /* Architecture-specific hardware disable .. */
 566         ptrace_disable(child);
 567
 568         write_lock_irq(&tasklist_lock);
 569         /*
 570          * We rely on ptrace_freeze_traced(). It can't be killed and
 571          * untraced by another thread, it can't be a zombie.
 572          */
 573         WARN_ON(!child->ptrace || child->exit_state);
 574         /*
 575          * tasklist_lock avoids the race with wait_task_stopped(), see
 576          * the comment in ptrace_resume().
 577          */
 578         child->exit_code = data;
 579         __ptrace_detach(current, child);
 580         write_unlock_irq(&tasklist_lock);
 581
 582         proc_ptrace_connector(child, PTRACE_DETACH);
 583
 584         return 0;
 585 }
 586
 587 /*
 588  * Detach all tasks we were using ptrace on. Called with tasklist held
 589  * for writing.
 590  */
 591 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
 592 {
 593         struct task_struct *p, *n;
 594
 595         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
 596                 if (unlikely(p->ptrace & PT_EXITKILL))
 597                         send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
 598
 599                 if (__ptrace_detach(tracer, p))
 600                         list_add(&p->ptrace_entry, dead);
 601         }
 602 }
 603
 604 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
 605 {
 606         int copied = 0;
 607
 608         while (len > 0) {
 609                 char buf[128];
 610                 int this_len, retval;
 611
 612                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 613                 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
 614
 615                 if (!retval) {
 616                         if (copied)
 617                                 break;
 618                         return -EIO;
 619                 }
 620                 if (copy_to_user(dst, buf, retval))
 621                         return -EFAULT;
 622                 copied += retval;
 623                 src += retval;
 624                 dst += retval;
 625                 len -= retval;
 626         }
 627         return copied;
 628 }
 629
 630 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
 631 {
 632         int copied = 0;
 633
 634         while (len > 0) {
 635                 char buf[128];
 636                 int this_len, retval;
 637
 638                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 639                 if (copy_from_user(buf, src, this_len))
 640                         return -EFAULT;
 641                 retval = ptrace_access_vm(tsk, dst, buf, this_len,
 642                                 FOLL_FORCE | FOLL_WRITE);
 643                 if (!retval) {
 644                         if (copied)
 645                                 break;
 646                         return -EIO;
 647                 }
 648                 copied += retval;
 649                 src += retval;
 650                 dst += retval;
 651                 len -= retval;
 652         }
 653         return copied;
 654 }
 655
 656 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 657 {
 658         unsigned flags;
 659
 660         if (data & ~(unsigned long)PTRACE_O_MASK)
 661                 return -EINVAL;
 662
 663         if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
 664                 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
 665                     !IS_ENABLED(CONFIG_SECCOMP))
 666                         return -EINVAL;
 667
 668                 if (!capable(CAP_SYS_ADMIN))
 669                         return -EPERM;
 670
 671                 if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
 672                     current->ptrace & PT_SUSPEND_SECCOMP)
 673                         return -EPERM;
 674         }
 675
 676         /* Avoid intermediate state when all opts are cleared */
 677         flags = child->ptrace;
 678         flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
 679         flags |= (data << PT_OPT_FLAG_SHIFT);
 680         child->ptrace = flags;
 681
 682         return 0;
 683 }
 684
 685 static int ptrace_getsiginfo(struct task_struct *child, 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(info, child->last_siginfo);
 694                         error = 0;
 695                 }
 696                 unlock_task_sighand(child, &flags);
 697         }
 698         return error;
 699 }
 700
 701 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
 702 {
 703         unsigned long flags;
 704         int error = -ESRCH;
 705
 706         if (lock_task_sighand(child, &flags)) {
 707                 error = -EINVAL;
 708                 if (likely(child->last_siginfo != NULL)) {
 709                         copy_siginfo(child->last_siginfo, info);
 710                         error = 0;
 711                 }
 712                 unlock_task_sighand(child, &flags);
 713         }
 714         return error;
 715 }
 716
 717 static int ptrace_peek_siginfo(struct task_struct *child,
 718                                 unsigned long addr,
 719                                 unsigned long data)
 720 {
 721         struct ptrace_peeksiginfo_args arg;
 722         struct sigpending *pending;
 723         struct sigqueue *q;
 724         int ret, i;
 725
 726         ret = copy_from_user(&arg, (void __user *) addr,
 727                                 sizeof(struct ptrace_peeksiginfo_args));
 728         if (ret)
 729                 return -EFAULT;
 730
 731         if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
 732                 return -EINVAL; /* unknown flags */
 733
 734         if (arg.nr < 0)
 735                 return -EINVAL;
 736
 737         /* Ensure arg.off fits in an unsigned long */
 738         if (arg.off > ULONG_MAX)
 739                 return 0;
 740
 741         if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
 742                 pending = &child->signal->shared_pending;
 743         else
 744                 pending = &child->pending;
 745
 746         for (i = 0; i < arg.nr; ) {
 747                 kernel_siginfo_t info;
 748                 unsigned long off = arg.off + i;
 749                 bool found = false;
 750
 751                 spin_lock_irq(&child->sighand->siglock);
 752                 list_for_each_entry(q, &pending->list, list) {
 753                         if (!off--) {
 754                                 found = true;
 755                                 copy_siginfo(&info, &q->info);
 756                                 break;
 757                         }
 758                 }
 759                 spin_unlock_irq(&child->sighand->siglock);
 760
 761                 if (!found) /* beyond the end of the list */
 762                         break;
 763
 764 #ifdef CONFIG_COMPAT
 765                 if (unlikely(in_compat_syscall())) {
 766                         compat_siginfo_t __user *uinfo = compat_ptr(data);
 767
 768                         if (copy_siginfo_to_user32(uinfo, &info)) {
 769                                 ret = -EFAULT;
 770                                 break;
 771                         }
 772
 773                 } else
 774 #endif
 775                 {
 776                         siginfo_t __user *uinfo = (siginfo_t __user *) data;
 777
 778                         if (copy_siginfo_to_user(uinfo, &info)) {
 779                                 ret = -EFAULT;
 780                                 break;
 781                         }
 782                 }
 783
 784                 data += sizeof(siginfo_t);
 785                 i++;
 786
 787                 if (signal_pending(current))
 788                         break;
 789
 790                 cond_resched();
 791         }
 792
 793         if (i > 0)
 794                 return i;
 795
 796         return ret;
 797 }
 798
 799 #ifdef CONFIG_RSEQ
 800 static long ptrace_get_rseq_configuration(struct task_struct *task,
 801                                           unsigned long size, void __user *data)
 802 {
 803         struct ptrace_rseq_configuration conf = {
 804                 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
 805                 .rseq_abi_size = sizeof(*task->rseq),
 806                 .signature = task->rseq_sig,
 807                 .flags = 0,
 808         };
 809
 810         size = min_t(unsigned long, size, sizeof(conf));
 811         if (copy_to_user(data, &conf, size))
 812                 return -EFAULT;
 813         return sizeof(conf);
 814 }
 815 #endif
 816
 817 #ifdef PTRACE_SINGLESTEP
 818 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
 819 #else
 820 #define is_singlestep(request)          0
 821 #endif
 822
 823 #ifdef PTRACE_SINGLEBLOCK
 824 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
 825 #else
 826 #define is_singleblock(request)         0
 827 #endif
 828
 829 #ifdef PTRACE_SYSEMU
 830 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
 831 #else
 832 #define is_sysemu_singlestep(request)   0
 833 #endif
 834
 835 static int ptrace_resume(struct task_struct *child, long request,
 836                          unsigned long data)
 837 {
 838         bool need_siglock;
 839
 840         if (!valid_signal(data))
 841                 return -EIO;
 842
 843         if (request == PTRACE_SYSCALL)
 844                 set_task_syscall_work(child, SYSCALL_TRACE);
 845         else
 846                 clear_task_syscall_work(child, SYSCALL_TRACE);
 847
 848 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
 849         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
 850                 set_task_syscall_work(child, SYSCALL_EMU);
 851         else
 852                 clear_task_syscall_work(child, SYSCALL_EMU);
 853 #endif
 854
 855         if (is_singleblock(request)) {
 856                 if (unlikely(!arch_has_block_step()))
 857                         return -EIO;
 858                 user_enable_block_step(child);
 859         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
 860                 if (unlikely(!arch_has_single_step()))
 861                         return -EIO;
 862                 user_enable_single_step(child);
 863         } else {
 864                 user_disable_single_step(child);
 865         }
 866
 867         /*
 868          * Change ->exit_code and ->state under siglock to avoid the race
 869          * with wait_task_stopped() in between; a non-zero ->exit_code will
 870          * wrongly look like another report from tracee.
 871          *
 872          * Note that we need siglock even if ->exit_code == data and/or this
 873          * status was not reported yet, the new status must not be cleared by
 874          * wait_task_stopped() after resume.
 875          *
 876          * If data == 0 we do not care if wait_task_stopped() reports the old
 877          * status and clears the code too; this can't race with the tracee, it
 878          * takes siglock after resume.
 879          */
 880         need_siglock = data && !thread_group_empty(current);
 881         if (need_siglock)
 882                 spin_lock_irq(&child->sighand->siglock);
 883         child->exit_code = data;
 884         wake_up_state(child, __TASK_TRACED);
 885         if (need_siglock)
 886                 spin_unlock_irq(&child->sighand->siglock);
 887
 888         return 0;
 889 }
 890
 891 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 892
 893 static const struct user_regset *
 894 find_regset(const struct user_regset_view *view, unsigned int type)
 895 {
 896         const struct user_regset *regset;
 897         int n;
 898
 899         for (n = 0; n < view->n; ++n) {
 900                 regset = view->regsets + n;
 901                 if (regset->core_note_type == type)
 902                         return regset;
 903         }
 904
 905         return NULL;
 906 }
 907
 908 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
 909                          struct iovec *kiov)
 910 {
 911         const struct user_regset_view *view = task_user_regset_view(task);
 912         const struct user_regset *regset = find_regset(view, type);
 913         int regset_no;
 914
 915         if (!regset || (kiov->iov_len % regset->size) != 0)
 916                 return -EINVAL;
 917
 918         regset_no = regset - view->regsets;
 919         kiov->iov_len = min(kiov->iov_len,
 920                             (__kernel_size_t) (regset->n * regset->size));
 921
 922         if (req == PTRACE_GETREGSET)
 923                 return copy_regset_to_user(task, view, regset_no, 0,
 924                                            kiov->iov_len, kiov->iov_base);
 925         else
 926                 return copy_regset_from_user(task, view, regset_no, 0,
 927                                              kiov->iov_len, kiov->iov_base);
 928 }
 929
 930 /*
 931  * This is declared in linux/regset.h and defined in machine-dependent
 932  * code.  We put the export here, near the primary machine-neutral use,
 933  * to ensure no machine forgets it.
 934  */
 935 EXPORT_SYMBOL_GPL(task_user_regset_view);
 936
 937 static unsigned long
 938 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
 939                               struct ptrace_syscall_info *info)
 940 {
 941         unsigned long args[ARRAY_SIZE(info->entry.args)];
 942         int i;
 943
 944         info->op = PTRACE_SYSCALL_INFO_ENTRY;
 945         info->entry.nr = syscall_get_nr(child, regs);
 946         syscall_get_arguments(child, regs, args);
 947         for (i = 0; i < ARRAY_SIZE(args); i++)
 948                 info->entry.args[i] = args[i];
 949
 950         /* args is the last field in struct ptrace_syscall_info.entry */
 951         return offsetofend(struct ptrace_syscall_info, entry.args);
 952 }
 953
 954 static unsigned long
 955 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
 956                                 struct ptrace_syscall_info *info)
 957 {
 958         /*
 959          * As struct ptrace_syscall_info.entry is currently a subset
 960          * of struct ptrace_syscall_info.seccomp, it makes sense to
 961          * initialize that subset using ptrace_get_syscall_info_entry().
 962          * This can be reconsidered in the future if these structures
 963          * diverge significantly enough.
 964          */
 965         ptrace_get_syscall_info_entry(child, regs, info);
 966         info->op = PTRACE_SYSCALL_INFO_SECCOMP;
 967         info->seccomp.ret_data = child->ptrace_message;
 968
 969         /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
 970         return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
 971 }
 972
 973 static unsigned long
 974 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
 975                              struct ptrace_syscall_info *info)
 976 {
 977         info->op = PTRACE_SYSCALL_INFO_EXIT;
 978         info->exit.rval = syscall_get_error(child, regs);
 979         info->exit.is_error = !!info->exit.rval;
 980         if (!info->exit.is_error)
 981                 info->exit.rval = syscall_get_return_value(child, regs);
 982
 983         /* is_error is the last field in struct ptrace_syscall_info.exit */
 984         return offsetofend(struct ptrace_syscall_info, exit.is_error);
 985 }
 986
 987 static int
 988 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
 989                         void __user *datavp)
 990 {
 991         struct pt_regs *regs = task_pt_regs(child);
 992         struct ptrace_syscall_info info = {
 993                 .op = PTRACE_SYSCALL_INFO_NONE,
 994                 .arch = syscall_get_arch(child),
 995                 .instruction_pointer = instruction_pointer(regs),
 996                 .stack_pointer = user_stack_pointer(regs),
 997         };
 998         unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
 999         unsigned long write_size;
1000
1001         /*
1002          * This does not need lock_task_sighand() to access
1003          * child->last_siginfo because ptrace_freeze_traced()
1004          * called earlier by ptrace_check_attach() ensures that
1005          * the tracee cannot go away and clear its last_siginfo.
1006          */
1007         switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
1008         case SIGTRAP | 0x80:
1009                 switch (child->ptrace_message) {
1010                 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
1011                         actual_size = ptrace_get_syscall_info_entry(child, regs,
1012                                                                     &info);
1013                         break;
1014                 case PTRACE_EVENTMSG_SYSCALL_EXIT:
1015                         actual_size = ptrace_get_syscall_info_exit(child, regs,
1016                                                                    &info);
1017                         break;
1018                 }
1019                 break;
1020         case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
1021                 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
1022                                                               &info);
1023                 break;
1024         }
1025
1026         write_size = min(actual_size, user_size);
1027         return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
1028 }
1029 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
1030
1031 int ptrace_request(struct task_struct *child, long request,
1032                    unsigned long addr, unsigned long data)
1033 {
1034         bool seized = child->ptrace & PT_SEIZED;
1035         int ret = -EIO;
1036         kernel_siginfo_t siginfo, *si;
1037         void __user *datavp = (void __user *) data;
1038         unsigned long __user *datalp = datavp;
1039         unsigned long flags;
1040
1041         switch (request) {
1042         case PTRACE_PEEKTEXT:
1043         case PTRACE_PEEKDATA:
1044                 return generic_ptrace_peekdata(child, addr, data);
1045         case PTRACE_POKETEXT:
1046         case PTRACE_POKEDATA:
1047                 return generic_ptrace_pokedata(child, addr, data);
1048
1049 #ifdef PTRACE_OLDSETOPTIONS
1050         case PTRACE_OLDSETOPTIONS:
1051 #endif
1052         case PTRACE_SETOPTIONS:
1053                 ret = ptrace_setoptions(child, data);
1054                 break;
1055         case PTRACE_GETEVENTMSG:
1056                 ret = put_user(child->ptrace_message, datalp);
1057                 break;
1058
1059         case PTRACE_PEEKSIGINFO:
1060                 ret = ptrace_peek_siginfo(child, addr, data);
1061                 break;
1062
1063         case PTRACE_GETSIGINFO:
1064                 ret = ptrace_getsiginfo(child, &siginfo);
1065                 if (!ret)
1066                         ret = copy_siginfo_to_user(datavp, &siginfo);
1067                 break;
1068
1069         case PTRACE_SETSIGINFO:
1070                 ret = copy_siginfo_from_user(&siginfo, datavp);
1071                 if (!ret)
1072                         ret = ptrace_setsiginfo(child, &siginfo);
1073                 break;
1074
1075         case PTRACE_GETSIGMASK: {
1076                 sigset_t *mask;
1077
1078                 if (addr != sizeof(sigset_t)) {
1079                         ret = -EINVAL;
1080                         break;
1081                 }
1082
1083                 if (test_tsk_restore_sigmask(child))
1084                         mask = &child->saved_sigmask;
1085                 else
1086                         mask = &child->blocked;
1087
1088                 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
1089                         ret = -EFAULT;
1090                 else
1091                         ret = 0;
1092
1093                 break;
1094         }
1095
1096         case PTRACE_SETSIGMASK: {
1097                 sigset_t new_set;
1098
1099                 if (addr != sizeof(sigset_t)) {
1100                         ret = -EINVAL;
1101                         break;
1102                 }
1103
1104                 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1105                         ret = -EFAULT;
1106                         break;
1107                 }
1108
1109                 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1110
1111                 /*
1112                  * Every thread does recalc_sigpending() after resume, so
1113                  * retarget_shared_pending() and recalc_sigpending() are not
1114                  * called here.
1115                  */
1116                 spin_lock_irq(&child->sighand->siglock);
1117                 child->blocked = new_set;
1118                 spin_unlock_irq(&child->sighand->siglock);
1119
1120                 clear_tsk_restore_sigmask(child);
1121
1122                 ret = 0;
1123                 break;
1124         }
1125
1126         case PTRACE_INTERRUPT:
1127                 /*
1128                  * Stop tracee without any side-effect on signal or job
1129                  * control.  At least one trap is guaranteed to happen
1130                  * after this request.  If @child is already trapped, the
1131                  * current trap is not disturbed and another trap will
1132                  * happen after the current trap is ended with PTRACE_CONT.
1133                  *
1134                  * The actual trap might not be PTRACE_EVENT_STOP trap but
1135                  * the pending condition is cleared regardless.
1136                  */
1137                 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1138                         break;
1139
1140                 /*
1141                  * INTERRUPT doesn't disturb existing trap sans one
1142                  * exception.  If ptracer issued LISTEN for the current
1143                  * STOP, this INTERRUPT should clear LISTEN and re-trap
1144                  * tracee into STOP.
1145                  */
1146                 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
1147                         ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
1148
1149                 unlock_task_sighand(child, &flags);
1150                 ret = 0;
1151                 break;
1152
1153         case PTRACE_LISTEN:
1154                 /*
1155                  * Listen for events.  Tracee must be in STOP.  It's not
1156                  * resumed per-se but is not considered to be in TRACED by
1157                  * wait(2) or ptrace(2).  If an async event (e.g. group
1158                  * stop state change) happens, tracee will enter STOP trap
1159                  * again.  Alternatively, ptracer can issue INTERRUPT to
1160                  * finish listening and re-trap tracee into STOP.
1161                  */
1162                 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1163                         break;
1164
1165                 si = child->last_siginfo;
1166                 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1167                         child->jobctl |= JOBCTL_LISTENING;
1168                         /*
1169                          * If NOTIFY is set, it means event happened between
1170                          * start of this trap and now.  Trigger re-trap.
1171                          */
1172                         if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1173                                 ptrace_signal_wake_up(child, true);
1174                         ret = 0;
1175                 }
1176                 unlock_task_sighand(child, &flags);
1177                 break;
1178
1179         case PTRACE_DETACH:      /* detach a process that was attached. */
1180                 ret = ptrace_detach(child, data);
1181                 break;
1182
1183 #ifdef CONFIG_BINFMT_ELF_FDPIC
1184         case PTRACE_GETFDPIC: {
1185                 struct mm_struct *mm = get_task_mm(child);
1186                 unsigned long tmp = 0;
1187
1188                 ret = -ESRCH;
1189                 if (!mm)
1190                         break;
1191
1192                 switch (addr) {
1193                 case PTRACE_GETFDPIC_EXEC:
1194                         tmp = mm->context.exec_fdpic_loadmap;
1195                         break;
1196                 case PTRACE_GETFDPIC_INTERP:
1197                         tmp = mm->context.interp_fdpic_loadmap;
1198                         break;
1199                 default:
1200                         break;
1201                 }
1202                 mmput(mm);
1203
1204                 ret = put_user(tmp, datalp);
1205                 break;
1206         }
1207 #endif
1208
1209 #ifdef PTRACE_SINGLESTEP
1210         case PTRACE_SINGLESTEP:
1211 #endif
1212 #ifdef PTRACE_SINGLEBLOCK
1213         case PTRACE_SINGLEBLOCK:
1214 #endif
1215 #ifdef PTRACE_SYSEMU
1216         case PTRACE_SYSEMU:
1217         case PTRACE_SYSEMU_SINGLESTEP:
1218 #endif
1219         case PTRACE_SYSCALL:
1220         case PTRACE_CONT:
1221                 return ptrace_resume(child, request, data);
1222
1223         case PTRACE_KILL:
1224                 if (child->exit_state)  /* already dead */
1225                         return 0;
1226                 return ptrace_resume(child, request, SIGKILL);
1227
1228 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1229         case PTRACE_GETREGSET:
1230         case PTRACE_SETREGSET: {
1231                 struct iovec kiov;
1232                 struct iovec __user *uiov = datavp;
1233
1234                 if (!access_ok(uiov, sizeof(*uiov)))
1235                         return -EFAULT;
1236
1237                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1238                     __get_user(kiov.iov_len, &uiov->iov_len))
1239                         return -EFAULT;
1240
1241                 ret = ptrace_regset(child, request, addr, &kiov);
1242                 if (!ret)
1243                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
1244                 break;
1245         }
1246
1247         case PTRACE_GET_SYSCALL_INFO:
1248                 ret = ptrace_get_syscall_info(child, addr, datavp);
1249                 break;
1250 #endif
1251
1252         case PTRACE_SECCOMP_GET_FILTER:
1253                 ret = seccomp_get_filter(child, addr, datavp);
1254                 break;
1255
1256         case PTRACE_SECCOMP_GET_METADATA:
1257                 ret = seccomp_get_metadata(child, addr, datavp);
1258                 break;
1259
1260 #ifdef CONFIG_RSEQ
1261         case PTRACE_GET_RSEQ_CONFIGURATION:
1262                 ret = ptrace_get_rseq_configuration(child, addr, datavp);
1263                 break;
1264 #endif
1265
1266         default:
1267                 break;
1268         }
1269
1270         return ret;
1271 }
1272
1273 #ifndef arch_ptrace_attach
1274 #define arch_ptrace_attach(child)       do { } while (0)
1275 #endif
1276
1277 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1278                 unsigned long, data)
1279 {
1280         struct task_struct *child;
1281         long ret;
1282
1283         if (request == PTRACE_TRACEME) {
1284                 ret = ptrace_traceme();
1285                 if (!ret)
1286                         arch_ptrace_attach(current);
1287                 goto out;
1288         }
1289
1290         child = find_get_task_by_vpid(pid);
1291         if (!child) {
1292                 ret = -ESRCH;
1293                 goto out;
1294         }
1295
1296         if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1297                 ret = ptrace_attach(child, request, addr, data);
1298                 /*
1299                  * Some architectures need to do book-keeping after
1300                  * a ptrace attach.
1301                  */
1302                 if (!ret)
1303                         arch_ptrace_attach(child);
1304                 goto out_put_task_struct;
1305         }
1306
1307         ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1308                                   request == PTRACE_INTERRUPT);
1309         if (ret < 0)
1310                 goto out_put_task_struct;
1311
1312         ret = arch_ptrace(child, request, addr, data);
1313         if (ret || request != PTRACE_DETACH)
1314                 ptrace_unfreeze_traced(child);
1315
1316  out_put_task_struct:
1317         put_task_struct(child);
1318  out:
1319         return ret;
1320 }
1321
1322 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1323                             unsigned long data)
1324 {
1325         unsigned long tmp;
1326         int copied;
1327
1328         copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1329         if (copied != sizeof(tmp))
1330                 return -EIO;
1331         return put_user(tmp, (unsigned long __user *)data);
1332 }
1333
1334 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1335                             unsigned long data)
1336 {
1337         int copied;
1338
1339         copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1340                         FOLL_FORCE | FOLL_WRITE);
1341         return (copied == sizeof(data)) ? 0 : -EIO;
1342 }
1343
1344 #if defined CONFIG_COMPAT
1345
1346 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1347                           compat_ulong_t addr, compat_ulong_t data)
1348 {
1349         compat_ulong_t __user *datap = compat_ptr(data);
1350         compat_ulong_t word;
1351         kernel_siginfo_t siginfo;
1352         int ret;
1353
1354         switch (request) {
1355         case PTRACE_PEEKTEXT:
1356         case PTRACE_PEEKDATA:
1357                 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1358                                 FOLL_FORCE);
1359                 if (ret != sizeof(word))
1360                         ret = -EIO;
1361                 else
1362                         ret = put_user(word, datap);
1363                 break;
1364
1365         case PTRACE_POKETEXT:
1366         case PTRACE_POKEDATA:
1367                 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1368                                 FOLL_FORCE | FOLL_WRITE);
1369                 ret = (ret != sizeof(data) ? -EIO : 0);
1370                 break;
1371
1372         case PTRACE_GETEVENTMSG:
1373                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1374                 break;
1375
1376         case PTRACE_GETSIGINFO:
1377                 ret = ptrace_getsiginfo(child, &siginfo);
1378                 if (!ret)
1379                         ret = copy_siginfo_to_user32(
1380                                 (struct compat_siginfo __user *) datap,
1381                                 &siginfo);
1382                 break;
1383
1384         case PTRACE_SETSIGINFO:
1385                 ret = copy_siginfo_from_user32(
1386                         &siginfo, (struct compat_siginfo __user *) datap);
1387                 if (!ret)
1388                         ret = ptrace_setsiginfo(child, &siginfo);
1389                 break;
1390 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1391         case PTRACE_GETREGSET:
1392         case PTRACE_SETREGSET:
1393         {
1394                 struct iovec kiov;
1395                 struct compat_iovec __user *uiov =
1396                         (struct compat_iovec __user *) datap;
1397                 compat_uptr_t ptr;
1398                 compat_size_t len;
1399
1400                 if (!access_ok(uiov, sizeof(*uiov)))
1401                         return -EFAULT;
1402
1403                 if (__get_user(ptr, &uiov->iov_base) ||
1404                     __get_user(len, &uiov->iov_len))
1405                         return -EFAULT;
1406
1407                 kiov.iov_base = compat_ptr(ptr);
1408                 kiov.iov_len = len;
1409
1410                 ret = ptrace_regset(child, request, addr, &kiov);
1411                 if (!ret)
1412                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
1413                 break;
1414         }
1415 #endif
1416
1417         default:
1418                 ret = ptrace_request(child, request, addr, data);
1419         }
1420
1421         return ret;
1422 }
1423
1424 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1425                        compat_long_t, addr, compat_long_t, data)
1426 {
1427         struct task_struct *child;
1428         long ret;
1429
1430         if (request == PTRACE_TRACEME) {
1431                 ret = ptrace_traceme();
1432                 goto out;
1433         }
1434
1435         child = find_get_task_by_vpid(pid);
1436         if (!child) {
1437                 ret = -ESRCH;
1438                 goto out;
1439         }
1440
1441         if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1442                 ret = ptrace_attach(child, request, addr, data);
1443                 /*
1444                  * Some architectures need to do book-keeping after
1445                  * a ptrace attach.
1446                  */
1447                 if (!ret)
1448                         arch_ptrace_attach(child);
1449                 goto out_put_task_struct;
1450         }
1451
1452         ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1453                                   request == PTRACE_INTERRUPT);
1454         if (!ret) {
1455                 ret = compat_arch_ptrace(child, request, addr, data);
1456                 if (ret || request != PTRACE_DETACH)
1457                         ptrace_unfreeze_traced(child);
1458         }
1459
1460  out_put_task_struct:
1461         put_task_struct(child);
1462  out:
1463         return ret;
1464 }
1465 #endif  /* CONFIG_COMPAT */