kernel/ptrace.c

   1 /*
   2  * linux/kernel/ptrace.c
   3  *
   4  * (C) Copyright 1999 Linus Torvalds
   5  *
   6  * Common interfaces for "ptrace()" which we do not want
   7  * to continually duplicate across every architecture.
   8  */
   9
  10 #include <linux/capability.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/errno.h>
  14 #include <linux/mm.h>
  15 #include <linux/highmem.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/security.h>
  19 #include <linux/signal.h>
  20 #include <linux/audit.h>
  21 #include <linux/pid_namespace.h>
  22 #include <linux/syscalls.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/regset.h>
  25 #include <linux/hw_breakpoint.h>
  26
  27
  28 /*
  29  * ptrace a task: make the debugger its new parent and
  30  * move it to the ptrace list.
  31  *
  32  * Must be called with the tasklist lock write-held.
  33  */
  34 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
  35 {
  36         BUG_ON(!list_empty(&child->ptrace_entry));
  37         list_add(&child->ptrace_entry, &new_parent->ptraced);
  38         child->parent = new_parent;
  39 }
  40
  41 /**
  42  * __ptrace_unlink - unlink ptracee and restore its execution state
  43  * @child: ptracee to be unlinked
  44  *
  45  * Remove @child from the ptrace list, move it back to the original parent,
  46  * and restore the execution state so that it conforms to the group stop
  47  * state.
  48  *
  49  * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
  50  * exiting.  For PTRACE_DETACH, unless the ptracee has been killed between
  51  * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
  52  * If the ptracer is exiting, the ptracee can be in any state.
  53  *
  54  * After detach, the ptracee should be in a state which conforms to the
  55  * group stop.  If the group is stopped or in the process of stopping, the
  56  * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
  57  * up from TASK_TRACED.
  58  *
  59  * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
  60  * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
  61  * to but in the opposite direction of what happens while attaching to a
  62  * stopped task.  However, in this direction, the intermediate RUNNING
  63  * state is not hidden even from the current ptracer and if it immediately
  64  * re-attaches and performs a WNOHANG wait(2), it may fail.
  65  *
  66  * CONTEXT:
  67  * write_lock_irq(tasklist_lock)
  68  */
  69 void __ptrace_unlink(struct task_struct *child)
  70 {
  71         BUG_ON(!child->ptrace);
  72
  73         child->ptrace = 0;
  74         child->parent = child->real_parent;
  75         list_del_init(&child->ptrace_entry);
  76
  77         spin_lock(&child->sighand->siglock);
  78
  79         /*
  80          * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
  81          * @child isn't dead.
  82          */
  83         if (!(child->flags & PF_EXITING) &&
  84             (child->signal->flags & SIGNAL_STOP_STOPPED ||
  85              child->signal->group_stop_count))
  86                 child->jobctl |= JOBCTL_STOP_PENDING;
  87
  88         /*
  89          * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
  90          * @child in the butt.  Note that @resume should be used iff @child
  91          * is in TASK_TRACED; otherwise, we might unduly disrupt
  92          * TASK_KILLABLE sleeps.
  93          */
  94         if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
  95                 signal_wake_up(child, task_is_traced(child));
  96
  97         spin_unlock(&child->sighand->siglock);
  98 }
  99
 100 /**
 101  * ptrace_check_attach - check whether ptracee is ready for ptrace operation
 102  * @child: ptracee to check for
 103  * @ignore_state: don't check whether @child is currently %TASK_TRACED
 104  *
 105  * Check whether @child is being ptraced by %current and ready for further
 106  * ptrace operations.  If @ignore_state is %false, @child also should be in
 107  * %TASK_TRACED state and on return the child is guaranteed to be traced
 108  * and not executing.  If @ignore_state is %true, @child can be in any
 109  * state.
 110  *
 111  * CONTEXT:
 112  * Grabs and releases tasklist_lock and @child->sighand->siglock.
 113  *
 114  * RETURNS:
 115  * 0 on success, -ESRCH if %child is not ready.
 116  */
 117 int ptrace_check_attach(struct task_struct *child, bool ignore_state)
 118 {
 119         int ret = -ESRCH;
 120
 121         /*
 122          * We take the read lock around doing both checks to close a
 123          * possible race where someone else was tracing our child and
 124          * detached between these two checks.  After this locked check,
 125          * we are sure that this is our traced child and that can only
 126          * be changed by us so it's not changing right after this.
 127          */
 128         read_lock(&tasklist_lock);
 129         if ((child->ptrace & PT_PTRACED) && child->parent == current) {
 130                 /*
 131                  * child->sighand can't be NULL, release_task()
 132                  * does ptrace_unlink() before __exit_signal().
 133                  */
 134                 spin_lock_irq(&child->sighand->siglock);
 135                 WARN_ON_ONCE(task_is_stopped(child));
 136                 if (task_is_traced(child) || ignore_state)
 137                         ret = 0;
 138                 spin_unlock_irq(&child->sighand->siglock);
 139         }
 140         read_unlock(&tasklist_lock);
 141
 142         if (!ret && !ignore_state)
 143                 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
 144
 145         /* All systems go.. */
 146         return ret;
 147 }
 148
 149 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 150 {
 151         const struct cred *cred = current_cred(), *tcred;
 152
 153         /* May we inspect the given task?
 154          * This check is used both for attaching with ptrace
 155          * and for allowing access to sensitive information in /proc.
 156          *
 157          * ptrace_attach denies several cases that /proc allows
 158          * because setting up the necessary parent/child relationship
 159          * or halting the specified task is impossible.
 160          */
 161         int dumpable = 0;
 162         /* Don't let security modules deny introspection */
 163         if (task == current)
 164                 return 0;
 165         rcu_read_lock();
 166         tcred = __task_cred(task);
 167         if (cred->user->user_ns == tcred->user->user_ns &&
 168             (cred->uid == tcred->euid &&
 169              cred->uid == tcred->suid &&
 170              cred->uid == tcred->uid  &&
 171              cred->gid == tcred->egid &&
 172              cred->gid == tcred->sgid &&
 173              cred->gid == tcred->gid))
 174                 goto ok;
 175         if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE))
 176                 goto ok;
 177         rcu_read_unlock();
 178         return -EPERM;
 179 ok:
 180         rcu_read_unlock();
 181         smp_rmb();
 182         if (task->mm)
 183                 dumpable = get_dumpable(task->mm);
 184         if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE))
 185                 return -EPERM;
 186
 187         return security_ptrace_access_check(task, mode);
 188 }
 189
 190 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
 191 {
 192         int err;
 193         task_lock(task);
 194         err = __ptrace_may_access(task, mode);
 195         task_unlock(task);
 196         return !err;
 197 }
 198
 199 static int ptrace_attach(struct task_struct *task)
 200 {
 201         int retval;
 202
 203         audit_ptrace(task);
 204
 205         retval = -EPERM;
 206         if (unlikely(task->flags & PF_KTHREAD))
 207                 goto out;
 208         if (same_thread_group(task, current))
 209                 goto out;
 210
 211         /*
 212          * Protect exec's credential calculations against our interference;
 213          * interference; SUID, SGID and LSM creds get determined differently
 214          * under ptrace.
 215          */
 216         retval = -ERESTARTNOINTR;
 217         if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
 218                 goto out;
 219
 220         task_lock(task);
 221         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
 222         task_unlock(task);
 223         if (retval)
 224                 goto unlock_creds;
 225
 226         write_lock_irq(&tasklist_lock);
 227         retval = -EPERM;
 228         if (unlikely(task->exit_state))
 229                 goto unlock_tasklist;
 230         if (task->ptrace)
 231                 goto unlock_tasklist;
 232
 233         task->ptrace = PT_PTRACED;
 234         if (task_ns_capable(task, CAP_SYS_PTRACE))
 235                 task->ptrace |= PT_PTRACE_CAP;
 236
 237         __ptrace_link(task, current);
 238         send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
 239
 240         spin_lock(&task->sighand->siglock);
 241
 242         /*
 243          * If the task is already STOPPED, set JOBCTL_STOP_PENDING and
 244          * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
 245          * will be cleared if the child completes the transition or any
 246          * event which clears the group stop states happens.  We'll wait
 247          * for the transition to complete before returning from this
 248          * function.
 249          *
 250          * This hides STOPPED -> RUNNING -> TRACED transition from the
 251          * attaching thread but a different thread in the same group can
 252          * still observe the transient RUNNING state.  IOW, if another
 253          * thread's WNOHANG wait(2) on the stopped tracee races against
 254          * ATTACH, the wait(2) may fail due to the transient RUNNING.
 255          *
 256          * The following task_is_stopped() test is safe as both transitions
 257          * in and out of STOPPED are protected by siglock.
 258          */
 259         if (task_is_stopped(task)) {
 260                 task->jobctl |= JOBCTL_STOP_PENDING | JOBCTL_TRAPPING;
 261                 signal_wake_up(task, 1);
 262         }
 263
 264         spin_unlock(&task->sighand->siglock);
 265
 266         retval = 0;
 267 unlock_tasklist:
 268         write_unlock_irq(&tasklist_lock);
 269 unlock_creds:
 270         mutex_unlock(&task->signal->cred_guard_mutex);
 271 out:
 272         if (!retval)
 273                 wait_event(current->signal->wait_chldexit,
 274                            !(task->jobctl & JOBCTL_TRAPPING));
 275         return retval;
 276 }
 277
 278 /**
 279  * ptrace_traceme  --  helper for PTRACE_TRACEME
 280  *
 281  * Performs checks and sets PT_PTRACED.
 282  * Should be used by all ptrace implementations for PTRACE_TRACEME.
 283  */
 284 static int ptrace_traceme(void)
 285 {
 286         int ret = -EPERM;
 287
 288         write_lock_irq(&tasklist_lock);
 289         /* Are we already being traced? */
 290         if (!current->ptrace) {
 291                 ret = security_ptrace_traceme(current->parent);
 292                 /*
 293                  * Check PF_EXITING to ensure ->real_parent has not passed
 294                  * exit_ptrace(). Otherwise we don't report the error but
 295                  * pretend ->real_parent untraces us right after return.
 296                  */
 297                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
 298                         current->ptrace = PT_PTRACED;
 299                         __ptrace_link(current, current->real_parent);
 300                 }
 301         }
 302         write_unlock_irq(&tasklist_lock);
 303
 304         return ret;
 305 }
 306
 307 /*
 308  * Called with irqs disabled, returns true if childs should reap themselves.
 309  */
 310 static int ignoring_children(struct sighand_struct *sigh)
 311 {
 312         int ret;
 313         spin_lock(&sigh->siglock);
 314         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
 315               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
 316         spin_unlock(&sigh->siglock);
 317         return ret;
 318 }
 319
 320 /*
 321  * Called with tasklist_lock held for writing.
 322  * Unlink a traced task, and clean it up if it was a traced zombie.
 323  * Return true if it needs to be reaped with release_task().
 324  * (We can't call release_task() here because we already hold tasklist_lock.)
 325  *
 326  * If it's a zombie, our attachedness prevented normal parent notification
 327  * or self-reaping.  Do notification now if it would have happened earlier.
 328  * If it should reap itself, return true.
 329  *
 330  * If it's our own child, there is no notification to do. But if our normal
 331  * children self-reap, then this child was prevented by ptrace and we must
 332  * reap it now, in that case we must also wake up sub-threads sleeping in
 333  * do_wait().
 334  */
 335 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
 336 {
 337         __ptrace_unlink(p);
 338
 339         if (p->exit_state == EXIT_ZOMBIE) {
 340                 if (!task_detached(p) && thread_group_empty(p)) {
 341                         if (!same_thread_group(p->real_parent, tracer))
 342                                 do_notify_parent(p, p->exit_signal);
 343                         else if (ignoring_children(tracer->sighand)) {
 344                                 __wake_up_parent(p, tracer);
 345                                 p->exit_signal = -1;
 346                         }
 347                 }
 348                 if (task_detached(p)) {
 349                         /* Mark it as in the process of being reaped. */
 350                         p->exit_state = EXIT_DEAD;
 351                         return true;
 352                 }
 353         }
 354
 355         return false;
 356 }
 357
 358 static int ptrace_detach(struct task_struct *child, unsigned int data)
 359 {
 360         bool dead = false;
 361
 362         if (!valid_signal(data))
 363                 return -EIO;
 364
 365         /* Architecture-specific hardware disable .. */
 366         ptrace_disable(child);
 367         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 368
 369         write_lock_irq(&tasklist_lock);
 370         /*
 371          * This child can be already killed. Make sure de_thread() or
 372          * our sub-thread doing do_wait() didn't do release_task() yet.
 373          */
 374         if (child->ptrace) {
 375                 child->exit_code = data;
 376                 dead = __ptrace_detach(current, child);
 377         }
 378         write_unlock_irq(&tasklist_lock);
 379
 380         if (unlikely(dead))
 381                 release_task(child);
 382
 383         return 0;
 384 }
 385
 386 /*
 387  * Detach all tasks we were using ptrace on. Called with tasklist held
 388  * for writing, and returns with it held too. But note it can release
 389  * and reacquire the lock.
 390  */
 391 void exit_ptrace(struct task_struct *tracer)
 392         __releases(&tasklist_lock)
 393         __acquires(&tasklist_lock)
 394 {
 395         struct task_struct *p, *n;
 396         LIST_HEAD(ptrace_dead);
 397
 398         if (likely(list_empty(&tracer->ptraced)))
 399                 return;
 400
 401         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
 402                 if (__ptrace_detach(tracer, p))
 403                         list_add(&p->ptrace_entry, &ptrace_dead);
 404         }
 405
 406         write_unlock_irq(&tasklist_lock);
 407         BUG_ON(!list_empty(&tracer->ptraced));
 408
 409         list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
 410                 list_del_init(&p->ptrace_entry);
 411                 release_task(p);
 412         }
 413
 414         write_lock_irq(&tasklist_lock);
 415 }
 416
 417 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
 418 {
 419         int copied = 0;
 420
 421         while (len > 0) {
 422                 char buf[128];
 423                 int this_len, retval;
 424
 425                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 426                 retval = access_process_vm(tsk, src, buf, this_len, 0);
 427                 if (!retval) {
 428                         if (copied)
 429                                 break;
 430                         return -EIO;
 431                 }
 432                 if (copy_to_user(dst, buf, retval))
 433                         return -EFAULT;
 434                 copied += retval;
 435                 src += retval;
 436                 dst += retval;
 437                 len -= retval;
 438         }
 439         return copied;
 440 }
 441
 442 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
 443 {
 444         int copied = 0;
 445
 446         while (len > 0) {
 447                 char buf[128];
 448                 int this_len, retval;
 449
 450                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 451                 if (copy_from_user(buf, src, this_len))
 452                         return -EFAULT;
 453                 retval = access_process_vm(tsk, dst, buf, this_len, 1);
 454                 if (!retval) {
 455                         if (copied)
 456                                 break;
 457                         return -EIO;
 458                 }
 459                 copied += retval;
 460                 src += retval;
 461                 dst += retval;
 462                 len -= retval;
 463         }
 464         return copied;
 465 }
 466
 467 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 468 {
 469         child->ptrace &= ~PT_TRACE_MASK;
 470
 471         if (data & PTRACE_O_TRACESYSGOOD)
 472                 child->ptrace |= PT_TRACESYSGOOD;
 473
 474         if (data & PTRACE_O_TRACEFORK)
 475                 child->ptrace |= PT_TRACE_FORK;
 476
 477         if (data & PTRACE_O_TRACEVFORK)
 478                 child->ptrace |= PT_TRACE_VFORK;
 479
 480         if (data & PTRACE_O_TRACECLONE)
 481                 child->ptrace |= PT_TRACE_CLONE;
 482
 483         if (data & PTRACE_O_TRACEEXEC)
 484                 child->ptrace |= PT_TRACE_EXEC;
 485
 486         if (data & PTRACE_O_TRACEVFORKDONE)
 487                 child->ptrace |= PT_TRACE_VFORK_DONE;
 488
 489         if (data & PTRACE_O_TRACEEXIT)
 490                 child->ptrace |= PT_TRACE_EXIT;
 491
 492         return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
 493 }
 494
 495 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 496 {
 497         unsigned long flags;
 498         int error = -ESRCH;
 499
 500         if (lock_task_sighand(child, &flags)) {
 501                 error = -EINVAL;
 502                 if (likely(child->last_siginfo != NULL)) {
 503                         *info = *child->last_siginfo;
 504                         error = 0;
 505                 }
 506                 unlock_task_sighand(child, &flags);
 507         }
 508         return error;
 509 }
 510
 511 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
 512 {
 513         unsigned long flags;
 514         int error = -ESRCH;
 515
 516         if (lock_task_sighand(child, &flags)) {
 517                 error = -EINVAL;
 518                 if (likely(child->last_siginfo != NULL)) {
 519                         *child->last_siginfo = *info;
 520                         error = 0;
 521                 }
 522                 unlock_task_sighand(child, &flags);
 523         }
 524         return error;
 525 }
 526
 527
 528 #ifdef PTRACE_SINGLESTEP
 529 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
 530 #else
 531 #define is_singlestep(request)          0
 532 #endif
 533
 534 #ifdef PTRACE_SINGLEBLOCK
 535 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
 536 #else
 537 #define is_singleblock(request)         0
 538 #endif
 539
 540 #ifdef PTRACE_SYSEMU
 541 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
 542 #else
 543 #define is_sysemu_singlestep(request)   0
 544 #endif
 545
 546 static int ptrace_resume(struct task_struct *child, long request,
 547                          unsigned long data)
 548 {
 549         if (!valid_signal(data))
 550                 return -EIO;
 551
 552         if (request == PTRACE_SYSCALL)
 553                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 554         else
 555                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 556
 557 #ifdef TIF_SYSCALL_EMU
 558         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
 559                 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 560         else
 561                 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 562 #endif
 563
 564         if (is_singleblock(request)) {
 565                 if (unlikely(!arch_has_block_step()))
 566                         return -EIO;
 567                 user_enable_block_step(child);
 568         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
 569                 if (unlikely(!arch_has_single_step()))
 570                         return -EIO;
 571                 user_enable_single_step(child);
 572         } else {
 573                 user_disable_single_step(child);
 574         }
 575
 576         child->exit_code = data;
 577         wake_up_state(child, __TASK_TRACED);
 578
 579         return 0;
 580 }
 581
 582 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 583
 584 static const struct user_regset *
 585 find_regset(const struct user_regset_view *view, unsigned int type)
 586 {
 587         const struct user_regset *regset;
 588         int n;
 589
 590         for (n = 0; n < view->n; ++n) {
 591                 regset = view->regsets + n;
 592                 if (regset->core_note_type == type)
 593                         return regset;
 594         }
 595
 596         return NULL;
 597 }
 598
 599 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
 600                          struct iovec *kiov)
 601 {
 602         const struct user_regset_view *view = task_user_regset_view(task);
 603         const struct user_regset *regset = find_regset(view, type);
 604         int regset_no;
 605
 606         if (!regset || (kiov->iov_len % regset->size) != 0)
 607                 return -EINVAL;
 608
 609         regset_no = regset - view->regsets;
 610         kiov->iov_len = min(kiov->iov_len,
 611                             (__kernel_size_t) (regset->n * regset->size));
 612
 613         if (req == PTRACE_GETREGSET)
 614                 return copy_regset_to_user(task, view, regset_no, 0,
 615                                            kiov->iov_len, kiov->iov_base);
 616         else
 617                 return copy_regset_from_user(task, view, regset_no, 0,
 618                                              kiov->iov_len, kiov->iov_base);
 619 }
 620
 621 #endif
 622
 623 int ptrace_request(struct task_struct *child, long request,
 624                    unsigned long addr, unsigned long data)
 625 {
 626         int ret = -EIO;
 627         siginfo_t siginfo;
 628         void __user *datavp = (void __user *) data;
 629         unsigned long __user *datalp = datavp;
 630
 631         switch (request) {
 632         case PTRACE_PEEKTEXT:
 633         case PTRACE_PEEKDATA:
 634                 return generic_ptrace_peekdata(child, addr, data);
 635         case PTRACE_POKETEXT:
 636         case PTRACE_POKEDATA:
 637                 return generic_ptrace_pokedata(child, addr, data);
 638
 639 #ifdef PTRACE_OLDSETOPTIONS
 640         case PTRACE_OLDSETOPTIONS:
 641 #endif
 642         case PTRACE_SETOPTIONS:
 643                 ret = ptrace_setoptions(child, data);
 644                 break;
 645         case PTRACE_GETEVENTMSG:
 646                 ret = put_user(child->ptrace_message, datalp);
 647                 break;
 648
 649         case PTRACE_GETSIGINFO:
 650                 ret = ptrace_getsiginfo(child, &siginfo);
 651                 if (!ret)
 652                         ret = copy_siginfo_to_user(datavp, &siginfo);
 653                 break;
 654
 655         case PTRACE_SETSIGINFO:
 656                 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
 657                         ret = -EFAULT;
 658                 else
 659                         ret = ptrace_setsiginfo(child, &siginfo);
 660                 break;
 661
 662         case PTRACE_DETACH:      /* detach a process that was attached. */
 663                 ret = ptrace_detach(child, data);
 664                 break;
 665
 666 #ifdef CONFIG_BINFMT_ELF_FDPIC
 667         case PTRACE_GETFDPIC: {
 668                 struct mm_struct *mm = get_task_mm(child);
 669                 unsigned long tmp = 0;
 670
 671                 ret = -ESRCH;
 672                 if (!mm)
 673                         break;
 674
 675                 switch (addr) {
 676                 case PTRACE_GETFDPIC_EXEC:
 677                         tmp = mm->context.exec_fdpic_loadmap;
 678                         break;
 679                 case PTRACE_GETFDPIC_INTERP:
 680                         tmp = mm->context.interp_fdpic_loadmap;
 681                         break;
 682                 default:
 683                         break;
 684                 }
 685                 mmput(mm);
 686
 687                 ret = put_user(tmp, datalp);
 688                 break;
 689         }
 690 #endif
 691
 692 #ifdef PTRACE_SINGLESTEP
 693         case PTRACE_SINGLESTEP:
 694 #endif
 695 #ifdef PTRACE_SINGLEBLOCK
 696         case PTRACE_SINGLEBLOCK:
 697 #endif
 698 #ifdef PTRACE_SYSEMU
 699         case PTRACE_SYSEMU:
 700         case PTRACE_SYSEMU_SINGLESTEP:
 701 #endif
 702         case PTRACE_SYSCALL:
 703         case PTRACE_CONT:
 704                 return ptrace_resume(child, request, data);
 705
 706         case PTRACE_KILL:
 707                 if (child->exit_state)  /* already dead */
 708                         return 0;
 709                 return ptrace_resume(child, request, SIGKILL);
 710
 711 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 712         case PTRACE_GETREGSET:
 713         case PTRACE_SETREGSET:
 714         {
 715                 struct iovec kiov;
 716                 struct iovec __user *uiov = datavp;
 717
 718                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
 719                         return -EFAULT;
 720
 721                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
 722                     __get_user(kiov.iov_len, &uiov->iov_len))
 723                         return -EFAULT;
 724
 725                 ret = ptrace_regset(child, request, addr, &kiov);
 726                 if (!ret)
 727                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
 728                 break;
 729         }
 730 #endif
 731         default:
 732                 break;
 733         }
 734
 735         return ret;
 736 }
 737
 738 static struct task_struct *ptrace_get_task_struct(pid_t pid)
 739 {
 740         struct task_struct *child;
 741
 742         rcu_read_lock();
 743         child = find_task_by_vpid(pid);
 744         if (child)
 745                 get_task_struct(child);
 746         rcu_read_unlock();
 747
 748         if (!child)
 749                 return ERR_PTR(-ESRCH);
 750         return child;
 751 }
 752
 753 #ifndef arch_ptrace_attach
 754 #define arch_ptrace_attach(child)       do { } while (0)
 755 #endif
 756
 757 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
 758                 unsigned long, data)
 759 {
 760         struct task_struct *child;
 761         long ret;
 762
 763         if (request == PTRACE_TRACEME) {
 764                 ret = ptrace_traceme();
 765                 if (!ret)
 766                         arch_ptrace_attach(current);
 767                 goto out;
 768         }
 769
 770         child = ptrace_get_task_struct(pid);
 771         if (IS_ERR(child)) {
 772                 ret = PTR_ERR(child);
 773                 goto out;
 774         }
 775
 776         if (request == PTRACE_ATTACH) {
 777                 ret = ptrace_attach(child);
 778                 /*
 779                  * Some architectures need to do book-keeping after
 780                  * a ptrace attach.
 781                  */
 782                 if (!ret)
 783                         arch_ptrace_attach(child);
 784                 goto out_put_task_struct;
 785         }
 786
 787         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 788         if (ret < 0)
 789                 goto out_put_task_struct;
 790
 791         ret = arch_ptrace(child, request, addr, data);
 792
 793  out_put_task_struct:
 794         put_task_struct(child);
 795  out:
 796         return ret;
 797 }
 798
 799 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 800                             unsigned long data)
 801 {
 802         unsigned long tmp;
 803         int copied;
 804
 805         copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
 806         if (copied != sizeof(tmp))
 807                 return -EIO;
 808         return put_user(tmp, (unsigned long __user *)data);
 809 }
 810
 811 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 812                             unsigned long data)
 813 {
 814         int copied;
 815
 816         copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
 817         return (copied == sizeof(data)) ? 0 : -EIO;
 818 }
 819
 820 #if defined CONFIG_COMPAT
 821 #include <linux/compat.h>
 822
 823 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 824                           compat_ulong_t addr, compat_ulong_t data)
 825 {
 826         compat_ulong_t __user *datap = compat_ptr(data);
 827         compat_ulong_t word;
 828         siginfo_t siginfo;
 829         int ret;
 830
 831         switch (request) {
 832         case PTRACE_PEEKTEXT:
 833         case PTRACE_PEEKDATA:
 834                 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
 835                 if (ret != sizeof(word))
 836                         ret = -EIO;
 837                 else
 838                         ret = put_user(word, datap);
 839                 break;
 840
 841         case PTRACE_POKETEXT:
 842         case PTRACE_POKEDATA:
 843                 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
 844                 ret = (ret != sizeof(data) ? -EIO : 0);
 845                 break;
 846
 847         case PTRACE_GETEVENTMSG:
 848                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
 849                 break;
 850
 851         case PTRACE_GETSIGINFO:
 852                 ret = ptrace_getsiginfo(child, &siginfo);
 853                 if (!ret)
 854                         ret = copy_siginfo_to_user32(
 855                                 (struct compat_siginfo __user *) datap,
 856                                 &siginfo);
 857                 break;
 858
 859         case PTRACE_SETSIGINFO:
 860                 memset(&siginfo, 0, sizeof siginfo);
 861                 if (copy_siginfo_from_user32(
 862                             &siginfo, (struct compat_siginfo __user *) datap))
 863                         ret = -EFAULT;
 864                 else
 865                         ret = ptrace_setsiginfo(child, &siginfo);
 866                 break;
 867 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 868         case PTRACE_GETREGSET:
 869         case PTRACE_SETREGSET:
 870         {
 871                 struct iovec kiov;
 872                 struct compat_iovec __user *uiov =
 873                         (struct compat_iovec __user *) datap;
 874                 compat_uptr_t ptr;
 875                 compat_size_t len;
 876
 877                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
 878                         return -EFAULT;
 879
 880                 if (__get_user(ptr, &uiov->iov_base) ||
 881                     __get_user(len, &uiov->iov_len))
 882                         return -EFAULT;
 883
 884                 kiov.iov_base = compat_ptr(ptr);
 885                 kiov.iov_len = len;
 886
 887                 ret = ptrace_regset(child, request, addr, &kiov);
 888                 if (!ret)
 889                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
 890                 break;
 891         }
 892 #endif
 893
 894         default:
 895                 ret = ptrace_request(child, request, addr, data);
 896         }
 897
 898         return ret;
 899 }
 900
 901 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
 902                                   compat_long_t addr, compat_long_t data)
 903 {
 904         struct task_struct *child;
 905         long ret;
 906
 907         if (request == PTRACE_TRACEME) {
 908                 ret = ptrace_traceme();
 909                 goto out;
 910         }
 911
 912         child = ptrace_get_task_struct(pid);
 913         if (IS_ERR(child)) {
 914                 ret = PTR_ERR(child);
 915                 goto out;
 916         }
 917
 918         if (request == PTRACE_ATTACH) {
 919                 ret = ptrace_attach(child);
 920                 /*
 921                  * Some architectures need to do book-keeping after
 922                  * a ptrace attach.
 923                  */
 924                 if (!ret)
 925                         arch_ptrace_attach(child);
 926                 goto out_put_task_struct;
 927         }
 928
 929         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 930         if (!ret)
 931                 ret = compat_arch_ptrace(child, request, addr, data);
 932
 933  out_put_task_struct:
 934         put_task_struct(child);
 935  out:
 936         return ret;
 937 }
 938 #endif  /* CONFIG_COMPAT */
 939
 940 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 941 int ptrace_get_breakpoints(struct task_struct *tsk)
 942 {
 943         if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
 944                 return 0;
 945
 946         return -1;
 947 }
 948
 949 void ptrace_put_breakpoints(struct task_struct *tsk)
 950 {
 951         if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
 952                 flush_ptrace_hw_breakpoint(tsk);
 953 }
 954 #endif /* CONFIG_HAVE_HW_BREAKPOINT */