linux/kernel/ptrace.c
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   1/*
   2 * linux/kernel/ptrace.c
   3 *
   4 * (C) Copyright 1999 Linus Torvalds
   5 *
   6 * Common interfaces for "ptrace()" which we do not want
   7 * to continually duplicate across every architecture.
   8 */
   9
  10#include <linux/capability.h>
  11#include <linux/export.h>
  12#include <linux/sched.h>
  13#include <linux/errno.h>
  14#include <linux/mm.h>
  15#include <linux/highmem.h>
  16#include <linux/pagemap.h>
  17#include <linux/ptrace.h>
  18#include <linux/security.h>
  19#include <linux/signal.h>
  20#include <linux/audit.h>
  21#include <linux/pid_namespace.h>
  22#include <linux/syscalls.h>
  23#include <linux/uaccess.h>
  24#include <linux/regset.h>
  25#include <linux/hw_breakpoint.h>
  26#include <linux/cn_proc.h>
  27
  28
  29static int ptrace_trapping_sleep_fn(void *flags)
  30{
  31        schedule();
  32        return 0;
  33}
  34
  35/*
  36 * ptrace a task: make the debugger its new parent and
  37 * move it to the ptrace list.
  38 *
  39 * Must be called with the tasklist lock write-held.
  40 */
  41void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
  42{
  43        BUG_ON(!list_empty(&child->ptrace_entry));
  44        list_add(&child->ptrace_entry, &new_parent->ptraced);
  45        child->parent = new_parent;
  46}
  47
  48/**
  49 * __ptrace_unlink - unlink ptracee and restore its execution state
  50 * @child: ptracee to be unlinked
  51 *
  52 * Remove @child from the ptrace list, move it back to the original parent,
  53 * and restore the execution state so that it conforms to the group stop
  54 * state.
  55 *
  56 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
  57 * exiting.  For PTRACE_DETACH, unless the ptracee has been killed between
  58 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
  59 * If the ptracer is exiting, the ptracee can be in any state.
  60 *
  61 * After detach, the ptracee should be in a state which conforms to the
  62 * group stop.  If the group is stopped or in the process of stopping, the
  63 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
  64 * up from TASK_TRACED.
  65 *
  66 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
  67 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
  68 * to but in the opposite direction of what happens while attaching to a
  69 * stopped task.  However, in this direction, the intermediate RUNNING
  70 * state is not hidden even from the current ptracer and if it immediately
  71 * re-attaches and performs a WNOHANG wait(2), it may fail.
  72 *
  73 * CONTEXT:
  74 * write_lock_irq(tasklist_lock)
  75 */
  76void __ptrace_unlink(struct task_struct *child)
  77{
  78        BUG_ON(!child->ptrace);
  79
  80        child->ptrace = 0;
  81        child->parent = child->real_parent;
  82        list_del_init(&child->ptrace_entry);
  83
  84        spin_lock(&child->sighand->siglock);
  85
  86        /*
  87         * Clear all pending traps and TRAPPING.  TRAPPING should be
  88         * cleared regardless of JOBCTL_STOP_PENDING.  Do it explicitly.
  89         */
  90        task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
  91        task_clear_jobctl_trapping(child);
  92
  93        /*
  94         * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
  95         * @child isn't dead.
  96         */
  97        if (!(child->flags & PF_EXITING) &&
  98            (child->signal->flags & SIGNAL_STOP_STOPPED ||
  99             child->signal->group_stop_count)) {
 100                child->jobctl |= JOBCTL_STOP_PENDING;
 101
 102                /*
 103                 * This is only possible if this thread was cloned by the
 104                 * traced task running in the stopped group, set the signal
 105                 * for the future reports.
 106                 * FIXME: we should change ptrace_init_task() to handle this
 107                 * case.
 108                 */
 109                if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
 110                        child->jobctl |= SIGSTOP;
 111        }
 112
 113        /*
 114         * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
 115         * @child in the butt.  Note that @resume should be used iff @child
 116         * is in TASK_TRACED; otherwise, we might unduly disrupt
 117         * TASK_KILLABLE sleeps.
 118         */
 119        if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
 120                signal_wake_up(child, task_is_traced(child));
 121
 122        spin_unlock(&child->sighand->siglock);
 123}
 124
 125/**
 126 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
 127 * @child: ptracee to check for
 128 * @ignore_state: don't check whether @child is currently %TASK_TRACED
 129 *
 130 * Check whether @child is being ptraced by %current and ready for further
 131 * ptrace operations.  If @ignore_state is %false, @child also should be in
 132 * %TASK_TRACED state and on return the child is guaranteed to be traced
 133 * and not executing.  If @ignore_state is %true, @child can be in any
 134 * state.
 135 *
 136 * CONTEXT:
 137 * Grabs and releases tasklist_lock and @child->sighand->siglock.
 138 *
 139 * RETURNS:
 140 * 0 on success, -ESRCH if %child is not ready.
 141 */
 142int ptrace_check_attach(struct task_struct *child, bool ignore_state)
 143{
 144        int ret = -ESRCH;
 145
 146        /*
 147         * We take the read lock around doing both checks to close a
 148         * possible race where someone else was tracing our child and
 149         * detached between these two checks.  After this locked check,
 150         * we are sure that this is our traced child and that can only
 151         * be changed by us so it's not changing right after this.
 152         */
 153        read_lock(&tasklist_lock);
 154        if ((child->ptrace & PT_PTRACED) && child->parent == current) {
 155                /*
 156                 * child->sighand can't be NULL, release_task()
 157                 * does ptrace_unlink() before __exit_signal().
 158                 */
 159                spin_lock_irq(&child->sighand->siglock);
 160                WARN_ON_ONCE(task_is_stopped(child));
 161                if (ignore_state || (task_is_traced(child) &&
 162                                     !(child->jobctl & JOBCTL_LISTENING)))
 163                        ret = 0;
 164                spin_unlock_irq(&child->sighand->siglock);
 165        }
 166        read_unlock(&tasklist_lock);
 167
 168        if (!ret && !ignore_state)
 169                ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
 170
 171        /* All systems go.. */
 172        return ret;
 173}
 174
 175static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
 176{
 177        if (mode & PTRACE_MODE_NOAUDIT)
 178                return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
 179        else
 180                return has_ns_capability(current, ns, CAP_SYS_PTRACE);
 181}
 182
 183/* Returns 0 on success, -errno on denial. */
 184static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 185{
 186        const struct cred *cred = current_cred(), *tcred;
 187
 188        /* May we inspect the given task?
 189         * This check is used both for attaching with ptrace
 190         * and for allowing access to sensitive information in /proc.
 191         *
 192         * ptrace_attach denies several cases that /proc allows
 193         * because setting up the necessary parent/child relationship
 194         * or halting the specified task is impossible.
 195         */
 196        int dumpable = 0;
 197        /* Don't let security modules deny introspection */
 198        if (task == current)
 199                return 0;
 200        rcu_read_lock();
 201        tcred = __task_cred(task);
 202        if (uid_eq(cred->uid, tcred->euid) &&
 203            uid_eq(cred->uid, tcred->suid) &&
 204            uid_eq(cred->uid, tcred->uid)  &&
 205            gid_eq(cred->gid, tcred->egid) &&
 206            gid_eq(cred->gid, tcred->sgid) &&
 207            gid_eq(cred->gid, tcred->gid))
 208                goto ok;
 209        if (ptrace_has_cap(tcred->user_ns, mode))
 210                goto ok;
 211        rcu_read_unlock();
 212        return -EPERM;
 213ok:
 214        rcu_read_unlock();
 215        smp_rmb();
 216        if (task->mm)
 217                dumpable = get_dumpable(task->mm);
 218        if (!dumpable  && !ptrace_has_cap(task_user_ns(task), mode))
 219                return -EPERM;
 220
 221        return security_ptrace_access_check(task, mode);
 222}
 223
 224bool ptrace_may_access(struct task_struct *task, unsigned int mode)
 225{
 226        int err;
 227        task_lock(task);
 228        err = __ptrace_may_access(task, mode);
 229        task_unlock(task);
 230        return !err;
 231}
 232
 233static int ptrace_attach(struct task_struct *task, long request,
 234                         unsigned long addr,
 235                         unsigned long flags)
 236{
 237        bool seize = (request == PTRACE_SEIZE);
 238        int retval;
 239
 240        retval = -EIO;
 241        if (seize) {
 242                if (addr != 0)
 243                        goto out;
 244                if (flags & ~(unsigned long)PTRACE_O_MASK)
 245                        goto out;
 246                flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
 247        } else {
 248                flags = PT_PTRACED;
 249        }
 250
 251        audit_ptrace(task);
 252
 253        retval = -EPERM;
 254        if (unlikely(task->flags & PF_KTHREAD))
 255                goto out;
 256        if (same_thread_group(task, current))
 257                goto out;
 258
 259        /*
 260         * Protect exec's credential calculations against our interference;
 261         * SUID, SGID and LSM creds get determined differently
 262         * under ptrace.
 263         */
 264        retval = -ERESTARTNOINTR;
 265        if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
 266                goto out;
 267
 268        task_lock(task);
 269        retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
 270        task_unlock(task);
 271        if (retval)
 272                goto unlock_creds;
 273
 274        write_lock_irq(&tasklist_lock);
 275        retval = -EPERM;
 276        if (unlikely(task->exit_state))
 277                goto unlock_tasklist;
 278        if (task->ptrace)
 279                goto unlock_tasklist;
 280
 281        if (seize)
 282                flags |= PT_SEIZED;
 283        if (ns_capable(task_user_ns(task), CAP_SYS_PTRACE))
 284                flags |= PT_PTRACE_CAP;
 285        task->ptrace = flags;
 286
 287        __ptrace_link(task, current);
 288
 289        /* SEIZE doesn't trap tracee on attach */
 290        if (!seize)
 291                send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
 292
 293        spin_lock(&task->sighand->siglock);
 294
 295        /*
 296         * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
 297         * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
 298         * will be cleared if the child completes the transition or any
 299         * event which clears the group stop states happens.  We'll wait
 300         * for the transition to complete before returning from this
 301         * function.
 302         *
 303         * This hides STOPPED -> RUNNING -> TRACED transition from the
 304         * attaching thread but a different thread in the same group can
 305         * still observe the transient RUNNING state.  IOW, if another
 306         * thread's WNOHANG wait(2) on the stopped tracee races against
 307         * ATTACH, the wait(2) may fail due to the transient RUNNING.
 308         *
 309         * The following task_is_stopped() test is safe as both transitions
 310         * in and out of STOPPED are protected by siglock.
 311         */
 312        if (task_is_stopped(task) &&
 313            task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
 314                signal_wake_up(task, 1);
 315
 316        spin_unlock(&task->sighand->siglock);
 317
 318        retval = 0;
 319unlock_tasklist:
 320        write_unlock_irq(&tasklist_lock);
 321unlock_creds:
 322        mutex_unlock(&task->signal->cred_guard_mutex);
 323out:
 324        if (!retval) {
 325                wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
 326                            ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE);
 327                proc_ptrace_connector(task, PTRACE_ATTACH);
 328        }
 329
 330        return retval;
 331}
 332
 333/**
 334 * ptrace_traceme  --  helper for PTRACE_TRACEME
 335 *
 336 * Performs checks and sets PT_PTRACED.
 337 * Should be used by all ptrace implementations for PTRACE_TRACEME.
 338 */
 339static int ptrace_traceme(void)
 340{
 341        int ret = -EPERM;
 342
 343        write_lock_irq(&tasklist_lock);
 344        /* Are we already being traced? */
 345        if (!current->ptrace) {
 346                ret = security_ptrace_traceme(current->parent);
 347                /*
 348                 * Check PF_EXITING to ensure ->real_parent has not passed
 349                 * exit_ptrace(). Otherwise we don't report the error but
 350                 * pretend ->real_parent untraces us right after return.
 351                 */
 352                if (!ret && !(current->real_parent->flags & PF_EXITING)) {
 353                        current->ptrace = PT_PTRACED;
 354                        __ptrace_link(current, current->real_parent);
 355                }
 356        }
 357        write_unlock_irq(&tasklist_lock);
 358
 359        return ret;
 360}
 361
 362/*
 363 * Called with irqs disabled, returns true if childs should reap themselves.
 364 */
 365static int ignoring_children(struct sighand_struct *sigh)
 366{
 367        int ret;
 368        spin_lock(&sigh->siglock);
 369        ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
 370              (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
 371        spin_unlock(&sigh->siglock);
 372        return ret;
 373}
 374
 375/*
 376 * Called with tasklist_lock held for writing.
 377 * Unlink a traced task, and clean it up if it was a traced zombie.
 378 * Return true if it needs to be reaped with release_task().
 379 * (We can't call release_task() here because we already hold tasklist_lock.)
 380 *
 381 * If it's a zombie, our attachedness prevented normal parent notification
 382 * or self-reaping.  Do notification now if it would have happened earlier.
 383 * If it should reap itself, return true.
 384 *
 385 * If it's our own child, there is no notification to do. But if our normal
 386 * children self-reap, then this child was prevented by ptrace and we must
 387 * reap it now, in that case we must also wake up sub-threads sleeping in
 388 * do_wait().
 389 */
 390static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
 391{
 392        bool dead;
 393
 394        __ptrace_unlink(p);
 395
 396        if (p->exit_state != EXIT_ZOMBIE)
 397                return false;
 398
 399        dead = !thread_group_leader(p);
 400
 401        if (!dead && thread_group_empty(p)) {
 402                if (!same_thread_group(p->real_parent, tracer))
 403                        dead = do_notify_parent(p, p->exit_signal);
 404                else if (ignoring_children(tracer->sighand)) {
 405                        __wake_up_parent(p, tracer);
 406                        dead = true;
 407                }
 408        }
 409        /* Mark it as in the process of being reaped. */
 410        if (dead)
 411                p->exit_state = EXIT_DEAD;
 412        return dead;
 413}
 414
 415static int ptrace_detach(struct task_struct *child, unsigned int data)
 416{
 417        bool dead = false;
 418
 419        if (!valid_signal(data))
 420                return -EIO;
 421
 422        /* Architecture-specific hardware disable .. */
 423        ptrace_disable(child);
 424        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 425
 426        write_lock_irq(&tasklist_lock);
 427        /*
 428         * This child can be already killed. Make sure de_thread() or
 429         * our sub-thread doing do_wait() didn't do release_task() yet.
 430         */
 431        if (child->ptrace) {
 432                child->exit_code = data;
 433                dead = __ptrace_detach(current, child);
 434        }
 435        write_unlock_irq(&tasklist_lock);
 436
 437        proc_ptrace_connector(child, PTRACE_DETACH);
 438        if (unlikely(dead))
 439                release_task(child);
 440
 441        return 0;
 442}
 443
 444/*
 445 * Detach all tasks we were using ptrace on. Called with tasklist held
 446 * for writing, and returns with it held too. But note it can release
 447 * and reacquire the lock.
 448 */
 449void exit_ptrace(struct task_struct *tracer)
 450        __releases(&tasklist_lock)
 451        __acquires(&tasklist_lock)
 452{
 453        struct task_struct *p, *n;
 454        LIST_HEAD(ptrace_dead);
 455
 456        if (likely(list_empty(&tracer->ptraced)))
 457                return;
 458
 459        list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
 460                if (__ptrace_detach(tracer, p))
 461                        list_add(&p->ptrace_entry, &ptrace_dead);
 462        }
 463
 464        write_unlock_irq(&tasklist_lock);
 465        BUG_ON(!list_empty(&tracer->ptraced));
 466
 467        list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
 468                list_del_init(&p->ptrace_entry);
 469                release_task(p);
 470        }
 471
 472        write_lock_irq(&tasklist_lock);
 473}
 474
 475int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
 476{
 477        int copied = 0;
 478
 479        while (len > 0) {
 480                char buf[128];
 481                int this_len, retval;
 482
 483                this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 484                retval = access_process_vm(tsk, src, buf, this_len, 0);
 485                if (!retval) {
 486                        if (copied)
 487                                break;
 488                        return -EIO;
 489                }
 490                if (copy_to_user(dst, buf, retval))
 491                        return -EFAULT;
 492                copied += retval;
 493                src += retval;
 494                dst += retval;
 495                len -= retval;
 496        }
 497        return copied;
 498}
 499
 500int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
 501{
 502        int copied = 0;
 503
 504        while (len > 0) {
 505                char buf[128];
 506                int this_len, retval;
 507
 508                this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
 509                if (copy_from_user(buf, src, this_len))
 510                        return -EFAULT;
 511                retval = access_process_vm(tsk, dst, buf, this_len, 1);
 512                if (!retval) {
 513                        if (copied)
 514                                break;
 515                        return -EIO;
 516                }
 517                copied += retval;
 518                src += retval;
 519                dst += retval;
 520                len -= retval;
 521        }
 522        return copied;
 523}
 524
 525static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 526{
 527        unsigned flags;
 528
 529        if (data & ~(unsigned long)PTRACE_O_MASK)
 530                return -EINVAL;
 531
 532        /* Avoid intermediate state when all opts are cleared */
 533        flags = child->ptrace;
 534        flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
 535        flags |= (data << PT_OPT_FLAG_SHIFT);
 536        child->ptrace = flags;
 537
 538        return 0;
 539}
 540
 541static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 542{
 543        unsigned long flags;
 544        int error = -ESRCH;
 545
 546        if (lock_task_sighand(child, &flags)) {
 547                error = -EINVAL;
 548                if (likely(child->last_siginfo != NULL)) {
 549                        *info = *child->last_siginfo;
 550                        error = 0;
 551                }
 552                unlock_task_sighand(child, &flags);
 553        }
 554        return error;
 555}
 556
 557static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
 558{
 559        unsigned long flags;
 560        int error = -ESRCH;
 561
 562        if (lock_task_sighand(child, &flags)) {
 563                error = -EINVAL;
 564                if (likely(child->last_siginfo != NULL)) {
 565                        *child->last_siginfo = *info;
 566                        error = 0;
 567                }
 568                unlock_task_sighand(child, &flags);
 569        }
 570        return error;
 571}
 572
 573
 574#ifdef PTRACE_SINGLESTEP
 575#define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
 576#else
 577#define is_singlestep(request)          0
 578#endif
 579
 580#ifdef PTRACE_SINGLEBLOCK
 581#define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
 582#else
 583#define is_singleblock(request)         0
 584#endif
 585
 586#ifdef PTRACE_SYSEMU
 587#define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
 588#else
 589#define is_sysemu_singlestep(request)   0
 590#endif
 591
 592static int ptrace_resume(struct task_struct *child, long request,
 593                         unsigned long data)
 594{
 595        if (!valid_signal(data))
 596                return -EIO;
 597
 598        if (request == PTRACE_SYSCALL)
 599                set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 600        else
 601                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 602
 603#ifdef TIF_SYSCALL_EMU
 604        if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
 605                set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 606        else
 607                clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 608#endif
 609
 610        if (is_singleblock(request)) {
 611                if (unlikely(!arch_has_block_step()))
 612                        return -EIO;
 613                user_enable_block_step(child);
 614        } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
 615                if (unlikely(!arch_has_single_step()))
 616                        return -EIO;
 617                user_enable_single_step(child);
 618        } else {
 619                user_disable_single_step(child);
 620        }
 621
 622        child->exit_code = data;
 623        wake_up_state(child, __TASK_TRACED);
 624
 625        return 0;
 626}
 627
 628#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 629
 630static const struct user_regset *
 631find_regset(const struct user_regset_view *view, unsigned int type)
 632{
 633        const struct user_regset *regset;
 634        int n;
 635
 636        for (n = 0; n < view->n; ++n) {
 637                regset = view->regsets + n;
 638                if (regset->core_note_type == type)
 639                        return regset;
 640        }
 641
 642        return NULL;
 643}
 644
 645static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
 646                         struct iovec *kiov)
 647{
 648        const struct user_regset_view *view = task_user_regset_view(task);
 649        const struct user_regset *regset = find_regset(view, type);
 650        int regset_no;
 651
 652        if (!regset || (kiov->iov_len % regset->size) != 0)
 653                return -EINVAL;
 654
 655        regset_no = regset - view->regsets;
 656        kiov->iov_len = min(kiov->iov_len,
 657                            (__kernel_size_t) (regset->n * regset->size));
 658
 659        if (req == PTRACE_GETREGSET)
 660                return copy_regset_to_user(task, view, regset_no, 0,
 661                                           kiov->iov_len, kiov->iov_base);
 662        else
 663                return copy_regset_from_user(task, view, regset_no, 0,
 664                                             kiov->iov_len, kiov->iov_base);
 665}
 666
 667#endif
 668
 669int ptrace_request(struct task_struct *child, long request,
 670                   unsigned long addr, unsigned long data)
 671{
 672        bool seized = child->ptrace & PT_SEIZED;
 673        int ret = -EIO;
 674        siginfo_t siginfo, *si;
 675        void __user *datavp = (void __user *) data;
 676        unsigned long __user *datalp = datavp;
 677        unsigned long flags;
 678
 679        switch (request) {
 680        case PTRACE_PEEKTEXT:
 681        case PTRACE_PEEKDATA:
 682                return generic_ptrace_peekdata(child, addr, data);
 683        case PTRACE_POKETEXT:
 684        case PTRACE_POKEDATA:
 685                return generic_ptrace_pokedata(child, addr, data);
 686
 687#ifdef PTRACE_OLDSETOPTIONS
 688        case PTRACE_OLDSETOPTIONS:
 689#endif
 690        case PTRACE_SETOPTIONS:
 691                ret = ptrace_setoptions(child, data);
 692                break;
 693        case PTRACE_GETEVENTMSG:
 694                ret = put_user(child->ptrace_message, datalp);
 695                break;
 696
 697        case PTRACE_GETSIGINFO:
 698                ret = ptrace_getsiginfo(child, &siginfo);
 699                if (!ret)
 700                        ret = copy_siginfo_to_user(datavp, &siginfo);
 701                break;
 702
 703        case PTRACE_SETSIGINFO:
 704                if (copy_from_user(&siginfo, datavp, sizeof siginfo))
 705                        ret = -EFAULT;
 706                else
 707                        ret = ptrace_setsiginfo(child, &siginfo);
 708                break;
 709
 710        case PTRACE_INTERRUPT:
 711                /*
 712                 * Stop tracee without any side-effect on signal or job
 713                 * control.  At least one trap is guaranteed to happen
 714                 * after this request.  If @child is already trapped, the
 715                 * current trap is not disturbed and another trap will
 716                 * happen after the current trap is ended with PTRACE_CONT.
 717                 *
 718                 * The actual trap might not be PTRACE_EVENT_STOP trap but
 719                 * the pending condition is cleared regardless.
 720                 */
 721                if (unlikely(!seized || !lock_task_sighand(child, &flags)))
 722                        break;
 723
 724                /*
 725                 * INTERRUPT doesn't disturb existing trap sans one
 726                 * exception.  If ptracer issued LISTEN for the current
 727                 * STOP, this INTERRUPT should clear LISTEN and re-trap
 728                 * tracee into STOP.
 729                 */
 730                if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
 731                        signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
 732
 733                unlock_task_sighand(child, &flags);
 734                ret = 0;
 735                break;
 736
 737        case PTRACE_LISTEN:
 738                /*
 739                 * Listen for events.  Tracee must be in STOP.  It's not
 740                 * resumed per-se but is not considered to be in TRACED by
 741                 * wait(2) or ptrace(2).  If an async event (e.g. group
 742                 * stop state change) happens, tracee will enter STOP trap
 743                 * again.  Alternatively, ptracer can issue INTERRUPT to
 744                 * finish listening and re-trap tracee into STOP.
 745                 */
 746                if (unlikely(!seized || !lock_task_sighand(child, &flags)))
 747                        break;
 748
 749                si = child->last_siginfo;
 750                if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
 751                        child->jobctl |= JOBCTL_LISTENING;
 752                        /*
 753                         * If NOTIFY is set, it means event happened between
 754                         * start of this trap and now.  Trigger re-trap.
 755                         */
 756                        if (child->jobctl & JOBCTL_TRAP_NOTIFY)
 757                                signal_wake_up(child, true);
 758                        ret = 0;
 759                }
 760                unlock_task_sighand(child, &flags);
 761                break;
 762
 763        case PTRACE_DETACH:      /* detach a process that was attached. */
 764                ret = ptrace_detach(child, data);
 765                break;
 766
 767#ifdef CONFIG_BINFMT_ELF_FDPIC
 768        case PTRACE_GETFDPIC: {
 769                struct mm_struct *mm = get_task_mm(child);
 770                unsigned long tmp = 0;
 771
 772                ret = -ESRCH;
 773                if (!mm)
 774                        break;
 775
 776                switch (addr) {
 777                case PTRACE_GETFDPIC_EXEC:
 778                        tmp = mm->context.exec_fdpic_loadmap;
 779                        break;
 780                case PTRACE_GETFDPIC_INTERP:
 781                        tmp = mm->context.interp_fdpic_loadmap;
 782                        break;
 783                default:
 784                        break;
 785                }
 786                mmput(mm);
 787
 788                ret = put_user(tmp, datalp);
 789                break;
 790        }
 791#endif
 792
 793#ifdef PTRACE_SINGLESTEP
 794        case PTRACE_SINGLESTEP:
 795#endif
 796#ifdef PTRACE_SINGLEBLOCK
 797        case PTRACE_SINGLEBLOCK:
 798#endif
 799#ifdef PTRACE_SYSEMU
 800        case PTRACE_SYSEMU:
 801        case PTRACE_SYSEMU_SINGLESTEP:
 802#endif
 803        case PTRACE_SYSCALL:
 804        case PTRACE_CONT:
 805                return ptrace_resume(child, request, data);
 806
 807        case PTRACE_KILL:
 808                if (child->exit_state)  /* already dead */
 809                        return 0;
 810                return ptrace_resume(child, request, SIGKILL);
 811
 812#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 813        case PTRACE_GETREGSET:
 814        case PTRACE_SETREGSET:
 815        {
 816                struct iovec kiov;
 817                struct iovec __user *uiov = datavp;
 818
 819                if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
 820                        return -EFAULT;
 821
 822                if (__get_user(kiov.iov_base, &uiov->iov_base) ||
 823                    __get_user(kiov.iov_len, &uiov->iov_len))
 824                        return -EFAULT;
 825
 826                ret = ptrace_regset(child, request, addr, &kiov);
 827                if (!ret)
 828                        ret = __put_user(kiov.iov_len, &uiov->iov_len);
 829                break;
 830        }
 831#endif
 832        default:
 833                break;
 834        }
 835
 836        return ret;
 837}
 838
 839static struct task_struct *ptrace_get_task_struct(pid_t pid)
 840{
 841        struct task_struct *child;
 842
 843        rcu_read_lock();
 844        child = find_task_by_vpid(pid);
 845        if (child)
 846                get_task_struct(child);
 847        rcu_read_unlock();
 848
 849        if (!child)
 850                return ERR_PTR(-ESRCH);
 851        return child;
 852}
 853
 854#ifndef arch_ptrace_attach
 855#define arch_ptrace_attach(child)       do { } while (0)
 856#endif
 857
 858SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
 859                unsigned long, data)
 860{
 861        struct task_struct *child;
 862        long ret;
 863
 864        if (request == PTRACE_TRACEME) {
 865                ret = ptrace_traceme();
 866                if (!ret)
 867                        arch_ptrace_attach(current);
 868                goto out;
 869        }
 870
 871        child = ptrace_get_task_struct(pid);
 872        if (IS_ERR(child)) {
 873                ret = PTR_ERR(child);
 874                goto out;
 875        }
 876
 877        if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
 878                ret = ptrace_attach(child, request, addr, data);
 879                /*
 880                 * Some architectures need to do book-keeping after
 881                 * a ptrace attach.
 882                 */
 883                if (!ret)
 884                        arch_ptrace_attach(child);
 885                goto out_put_task_struct;
 886        }
 887
 888        ret = ptrace_check_attach(child, request == PTRACE_KILL ||
 889                                  request == PTRACE_INTERRUPT);
 890        if (ret < 0)
 891                goto out_put_task_struct;
 892
 893        ret = arch_ptrace(child, request, addr, data);
 894
 895 out_put_task_struct:
 896        put_task_struct(child);
 897 out:
 898        return ret;
 899}
 900
 901int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
 902                            unsigned long data)
 903{
 904        unsigned long tmp;
 905        int copied;
 906
 907        copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
 908        if (copied != sizeof(tmp))
 909                return -EIO;
 910        return put_user(tmp, (unsigned long __user *)data);
 911}
 912
 913int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
 914                            unsigned long data)
 915{
 916        int copied;
 917
 918        copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
 919        return (copied == sizeof(data)) ? 0 : -EIO;
 920}
 921
 922#if defined CONFIG_COMPAT
 923#include <linux/compat.h>
 924
 925int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 926                          compat_ulong_t addr, compat_ulong_t data)
 927{
 928        compat_ulong_t __user *datap = compat_ptr(data);
 929        compat_ulong_t word;
 930        siginfo_t siginfo;
 931        int ret;
 932
 933        switch (request) {
 934        case PTRACE_PEEKTEXT:
 935        case PTRACE_PEEKDATA:
 936                ret = access_process_vm(child, addr, &word, sizeof(word), 0);
 937                if (ret != sizeof(word))
 938                        ret = -EIO;
 939                else
 940                        ret = put_user(word, datap);
 941                break;
 942
 943        case PTRACE_POKETEXT:
 944        case PTRACE_POKEDATA:
 945                ret = access_process_vm(child, addr, &data, sizeof(data), 1);
 946                ret = (ret != sizeof(data) ? -EIO : 0);
 947                break;
 948
 949        case PTRACE_GETEVENTMSG:
 950                ret = put_user((compat_ulong_t) child->ptrace_message, datap);
 951                break;
 952
 953        case PTRACE_GETSIGINFO:
 954                ret = ptrace_getsiginfo(child, &siginfo);
 955                if (!ret)
 956                        ret = copy_siginfo_to_user32(
 957                                (struct compat_siginfo __user *) datap,
 958                                &siginfo);
 959                break;
 960
 961        case PTRACE_SETSIGINFO:
 962                memset(&siginfo, 0, sizeof siginfo);
 963                if (copy_siginfo_from_user32(
 964                            &siginfo, (struct compat_siginfo __user *) datap))
 965                        ret = -EFAULT;
 966                else
 967                        ret = ptrace_setsiginfo(child, &siginfo);
 968                break;
 969#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
 970        case PTRACE_GETREGSET:
 971        case PTRACE_SETREGSET:
 972        {
 973                struct iovec kiov;
 974                struct compat_iovec __user *uiov =
 975                        (struct compat_iovec __user *) datap;
 976                compat_uptr_t ptr;
 977                compat_size_t len;
 978
 979                if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
 980                        return -EFAULT;
 981
 982                if (__get_user(ptr, &uiov->iov_base) ||
 983                    __get_user(len, &uiov->iov_len))
 984                        return -EFAULT;
 985
 986                kiov.iov_base = compat_ptr(ptr);
 987                kiov.iov_len = len;
 988
 989                ret = ptrace_regset(child, request, addr, &kiov);
 990                if (!ret)
 991                        ret = __put_user(kiov.iov_len, &uiov->iov_len);
 992                break;
 993        }
 994#endif
 995
 996        default:
 997                ret = ptrace_request(child, request, addr, data);
 998        }
 999
1000        return ret;
1001}
1002
1003asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
1004                                  compat_long_t addr, compat_long_t data)
1005{
1006        struct task_struct *child;
1007        long ret;
1008
1009        if (request == PTRACE_TRACEME) {
1010                ret = ptrace_traceme();
1011                goto out;
1012        }
1013
1014        child = ptrace_get_task_struct(pid);
1015        if (IS_ERR(child)) {
1016                ret = PTR_ERR(child);
1017                goto out;
1018        }
1019
1020        if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1021                ret = ptrace_attach(child, request, addr, data);
1022                /*
1023                 * Some architectures need to do book-keeping after
1024                 * a ptrace attach.
1025                 */
1026                if (!ret)
1027                        arch_ptrace_attach(child);
1028                goto out_put_task_struct;
1029        }
1030
1031        ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1032                                  request == PTRACE_INTERRUPT);
1033        if (!ret)
1034                ret = compat_arch_ptrace(child, request, addr, data);
1035
1036 out_put_task_struct:
1037        put_task_struct(child);
1038 out:
1039        return ret;
1040}
1041#endif  /* CONFIG_COMPAT */
1042
1043#ifdef CONFIG_HAVE_HW_BREAKPOINT
1044int ptrace_get_breakpoints(struct task_struct *tsk)
1045{
1046        if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt))
1047                return 0;
1048
1049        return -1;
1050}
1051
1052void ptrace_put_breakpoints(struct task_struct *tsk)
1053{
1054        if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt))
1055                flush_ptrace_hw_breakpoint(tsk);
1056}
1057#endif /* CONFIG_HAVE_HW_BREAKPOINT */
1058
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