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 /* 189 * Ensure that nothing can wake it up, even SIGKILL 190 * 191 * A task is switched to this state while a ptrace operation is in progress; 192 * such that the ptrace operation is uninterruptible. 193 */ 194 static bool ptrace_freeze_traced(struct task_struct *task) 195 { 196 bool ret = false; 197 198 /* Lockless, nobody but us can set this flag */ 199 if (task->jobctl & JOBCTL_LISTENING) 200 return ret; 201 202 spin_lock_irq(&task->sighand->siglock); 203 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) && 204 !__fatal_signal_pending(task)) { 205 task->jobctl |= JOBCTL_PTRACE_FROZEN; 206 ret = true; 207 } 208 spin_unlock_irq(&task->sighand->siglock); 209 210 return ret; 211 } 212 213 static void ptrace_unfreeze_traced(struct task_struct *task) 214 { 215 unsigned long flags; 216 217 /* 218 * The child may be awake and may have cleared 219 * JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will 220 * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew. 221 */ 222 if (lock_task_sighand(task, &flags)) { 223 task->jobctl &= ~JOBCTL_PTRACE_FROZEN; 224 if (__fatal_signal_pending(task)) { 225 task->jobctl &= ~JOBCTL_TRACED; 226 wake_up_state(task, __TASK_TRACED); 227 } 228 unlock_task_sighand(task, &flags); 229 } 230 } 231 232 /** 233 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 234 * @child: ptracee to check for 235 * @ignore_state: don't check whether @child is currently %TASK_TRACED 236 * 237 * Check whether @child is being ptraced by %current and ready for further 238 * ptrace operations. If @ignore_state is %false, @child also should be in 239 * %TASK_TRACED state and on return the child is guaranteed to be traced 240 * and not executing. If @ignore_state is %true, @child can be in any 241 * state. 242 * 243 * CONTEXT: 244 * Grabs and releases tasklist_lock and @child->sighand->siglock. 245 * 246 * RETURNS: 247 * 0 on success, -ESRCH if %child is not ready. 248 */ 249 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 250 { 251 int ret = -ESRCH; 252 253 /* 254 * We take the read lock around doing both checks to close a 255 * possible race where someone else was tracing our child and 256 * detached between these two checks. After this locked check, 257 * we are sure that this is our traced child and that can only 258 * be changed by us so it's not changing right after this. 259 */ 260 read_lock(&tasklist_lock); 261 if (child->ptrace && child->parent == current) { 262 /* 263 * child->sighand can't be NULL, release_task() 264 * does ptrace_unlink() before __exit_signal(). 265 */ 266 if (ignore_state || ptrace_freeze_traced(child)) 267 ret = 0; 268 } 269 read_unlock(&tasklist_lock); 270 271 if (!ret && !ignore_state && 272 WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN))) 273 ret = -ESRCH; 274 275 return ret; 276 } 277 278 static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 279 { 280 if (mode & PTRACE_MODE_NOAUDIT) 281 return ns_capable_noaudit(ns, CAP_SYS_PTRACE); 282 return ns_capable(ns, CAP_SYS_PTRACE); 283 } 284 285 /* Returns 0 on success, -errno on denial. */ 286 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 287 { 288 const struct cred *cred = current_cred(), *tcred; 289 struct mm_struct *mm; 290 kuid_t caller_uid; 291 kgid_t caller_gid; 292 293 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) { 294 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n"); 295 return -EPERM; 296 } 297 298 /* May we inspect the given task? 299 * This check is used both for attaching with ptrace 300 * and for allowing access to sensitive information in /proc. 301 * 302 * ptrace_attach denies several cases that /proc allows 303 * because setting up the necessary parent/child relationship 304 * or halting the specified task is impossible. 305 */ 306 307 /* Don't let security modules deny introspection */ 308 if (same_thread_group(task, current)) 309 return 0; 310 rcu_read_lock(); 311 if (mode & PTRACE_MODE_FSCREDS) { 312 caller_uid = cred->fsuid; 313 caller_gid = cred->fsgid; 314 } else { 315 /* 316 * Using the euid would make more sense here, but something 317 * in userland might rely on the old behavior, and this 318 * shouldn't be a security problem since 319 * PTRACE_MODE_REALCREDS implies that the caller explicitly 320 * used a syscall that requests access to another process 321 * (and not a filesystem syscall to procfs). 322 */ 323 caller_uid = cred->uid; 324 caller_gid = cred->gid; 325 } 326 tcred = __task_cred(task); 327 if (uid_eq(caller_uid, tcred->euid) && 328 uid_eq(caller_uid, tcred->suid) && 329 uid_eq(caller_uid, tcred->uid) && 330 gid_eq(caller_gid, tcred->egid) && 331 gid_eq(caller_gid, tcred->sgid) && 332 gid_eq(caller_gid, tcred->gid)) 333 goto ok; 334 if (ptrace_has_cap(tcred->user_ns, mode)) 335 goto ok; 336 rcu_read_unlock(); 337 return -EPERM; 338 ok: 339 rcu_read_unlock(); 340 /* 341 * If a task drops privileges and becomes nondumpable (through a syscall 342 * like setresuid()) while we are trying to access it, we must ensure 343 * that the dumpability is read after the credentials; otherwise, 344 * we may be able to attach to a task that we shouldn't be able to 345 * attach to (as if the task had dropped privileges without becoming 346 * nondumpable). 347 * Pairs with a write barrier in commit_creds(). 348 */ 349 smp_rmb(); 350 mm = task->mm; 351 if (mm && 352 ((get_dumpable(mm) != SUID_DUMP_USER) && 353 !ptrace_has_cap(mm->user_ns, mode))) 354 return -EPERM; 355 356 return security_ptrace_access_check(task, mode); 357 } 358 359 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 360 { 361 int err; 362 task_lock(task); 363 err = __ptrace_may_access(task, mode); 364 task_unlock(task); 365 return !err; 366 } 367 368 static int check_ptrace_options(unsigned long data) 369 { 370 if (data & ~(unsigned long)PTRACE_O_MASK) 371 return -EINVAL; 372 373 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 374 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 375 !IS_ENABLED(CONFIG_SECCOMP)) 376 return -EINVAL; 377 378 if (!capable(CAP_SYS_ADMIN)) 379 return -EPERM; 380 381 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 382 current->ptrace & PT_SUSPEND_SECCOMP) 383 return -EPERM; 384 } 385 return 0; 386 } 387 388 static int ptrace_attach(struct task_struct *task, long request, 389 unsigned long addr, 390 unsigned long flags) 391 { 392 bool seize = (request == PTRACE_SEIZE); 393 int retval; 394 395 retval = -EIO; 396 if (seize) { 397 if (addr != 0) 398 goto out; 399 /* 400 * This duplicates the check in check_ptrace_options() because 401 * ptrace_attach() and ptrace_setoptions() have historically 402 * used different error codes for unknown ptrace options. 403 */ 404 if (flags & ~(unsigned long)PTRACE_O_MASK) 405 goto out; 406 retval = check_ptrace_options(flags); 407 if (retval) 408 return retval; 409 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 410 } else { 411 flags = PT_PTRACED; 412 } 413 414 audit_ptrace(task); 415 416 retval = -EPERM; 417 if (unlikely(task->flags & PF_KTHREAD)) 418 goto out; 419 if (same_thread_group(task, current)) 420 goto out; 421 422 /* 423 * Protect exec's credential calculations against our interference; 424 * SUID, SGID and LSM creds get determined differently 425 * under ptrace. 426 */ 427 retval = -ERESTARTNOINTR; 428 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 429 goto out; 430 431 task_lock(task); 432 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); 433 task_unlock(task); 434 if (retval) 435 goto unlock_creds; 436 437 write_lock_irq(&tasklist_lock); 438 retval = -EPERM; 439 if (unlikely(task->exit_state)) 440 goto unlock_tasklist; 441 if (task->ptrace) 442 goto unlock_tasklist; 443 444 task->ptrace = flags; 445 446 ptrace_link(task, current); 447 448 /* SEIZE doesn't trap tracee on attach */ 449 if (!seize) 450 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 451 452 spin_lock(&task->sighand->siglock); 453 454 /* 455 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 456 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 457 * will be cleared if the child completes the transition or any 458 * event which clears the group stop states happens. We'll wait 459 * for the transition to complete before returning from this 460 * function. 461 * 462 * This hides STOPPED -> RUNNING -> TRACED transition from the 463 * attaching thread but a different thread in the same group can 464 * still observe the transient RUNNING state. IOW, if another 465 * thread's WNOHANG wait(2) on the stopped tracee races against 466 * ATTACH, the wait(2) may fail due to the transient RUNNING. 467 * 468 * The following task_is_stopped() test is safe as both transitions 469 * in and out of STOPPED are protected by siglock. 470 */ 471 if (task_is_stopped(task) && 472 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) { 473 task->jobctl &= ~JOBCTL_STOPPED; 474 signal_wake_up_state(task, __TASK_STOPPED); 475 } 476 477 spin_unlock(&task->sighand->siglock); 478 479 retval = 0; 480 unlock_tasklist: 481 write_unlock_irq(&tasklist_lock); 482 unlock_creds: 483 mutex_unlock(&task->signal->cred_guard_mutex); 484 out: 485 if (!retval) { 486 /* 487 * We do not bother to change retval or clear JOBCTL_TRAPPING 488 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 489 * not return to user-mode, it will exit and clear this bit in 490 * __ptrace_unlink() if it wasn't already cleared by the tracee; 491 * and until then nobody can ptrace this task. 492 */ 493 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 494 proc_ptrace_connector(task, PTRACE_ATTACH); 495 } 496 497 return retval; 498 } 499 500 /** 501 * ptrace_traceme -- helper for PTRACE_TRACEME 502 * 503 * Performs checks and sets PT_PTRACED. 504 * Should be used by all ptrace implementations for PTRACE_TRACEME. 505 */ 506 static int ptrace_traceme(void) 507 { 508 int ret = -EPERM; 509 510 write_lock_irq(&tasklist_lock); 511 /* Are we already being traced? */ 512 if (!current->ptrace) { 513 ret = security_ptrace_traceme(current->parent); 514 /* 515 * Check PF_EXITING to ensure ->real_parent has not passed 516 * exit_ptrace(). Otherwise we don't report the error but 517 * pretend ->real_parent untraces us right after return. 518 */ 519 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 520 current->ptrace = PT_PTRACED; 521 ptrace_link(current, current->real_parent); 522 } 523 } 524 write_unlock_irq(&tasklist_lock); 525 526 return ret; 527 } 528 529 /* 530 * Called with irqs disabled, returns true if childs should reap themselves. 531 */ 532 static int ignoring_children(struct sighand_struct *sigh) 533 { 534 int ret; 535 spin_lock(&sigh->siglock); 536 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 537 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 538 spin_unlock(&sigh->siglock); 539 return ret; 540 } 541 542 /* 543 * Called with tasklist_lock held for writing. 544 * Unlink a traced task, and clean it up if it was a traced zombie. 545 * Return true if it needs to be reaped with release_task(). 546 * (We can't call release_task() here because we already hold tasklist_lock.) 547 * 548 * If it's a zombie, our attachedness prevented normal parent notification 549 * or self-reaping. Do notification now if it would have happened earlier. 550 * If it should reap itself, return true. 551 * 552 * If it's our own child, there is no notification to do. But if our normal 553 * children self-reap, then this child was prevented by ptrace and we must 554 * reap it now, in that case we must also wake up sub-threads sleeping in 555 * do_wait(). 556 */ 557 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 558 { 559 bool dead; 560 561 __ptrace_unlink(p); 562 563 if (p->exit_state != EXIT_ZOMBIE) 564 return false; 565 566 dead = !thread_group_leader(p); 567 568 if (!dead && thread_group_empty(p)) { 569 if (!same_thread_group(p->real_parent, tracer)) 570 dead = do_notify_parent(p, p->exit_signal); 571 else if (ignoring_children(tracer->sighand)) { 572 __wake_up_parent(p, tracer); 573 dead = true; 574 } 575 } 576 /* Mark it as in the process of being reaped. */ 577 if (dead) 578 p->exit_state = EXIT_DEAD; 579 return dead; 580 } 581 582 static int ptrace_detach(struct task_struct *child, unsigned int data) 583 { 584 if (!valid_signal(data)) 585 return -EIO; 586 587 /* Architecture-specific hardware disable .. */ 588 ptrace_disable(child); 589 590 write_lock_irq(&tasklist_lock); 591 /* 592 * We rely on ptrace_freeze_traced(). It can't be killed and 593 * untraced by another thread, it can't be a zombie. 594 */ 595 WARN_ON(!child->ptrace || child->exit_state); 596 /* 597 * tasklist_lock avoids the race with wait_task_stopped(), see 598 * the comment in ptrace_resume(). 599 */ 600 child->exit_code = data; 601 __ptrace_detach(current, child); 602 write_unlock_irq(&tasklist_lock); 603 604 proc_ptrace_connector(child, PTRACE_DETACH); 605 606 return 0; 607 } 608 609 /* 610 * Detach all tasks we were using ptrace on. Called with tasklist held 611 * for writing. 612 */ 613 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 614 { 615 struct task_struct *p, *n; 616 617 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 618 if (unlikely(p->ptrace & PT_EXITKILL)) 619 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 620 621 if (__ptrace_detach(tracer, p)) 622 list_add(&p->ptrace_entry, dead); 623 } 624 } 625 626 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 627 { 628 int copied = 0; 629 630 while (len > 0) { 631 char buf[128]; 632 int this_len, retval; 633 634 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 635 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 636 637 if (!retval) { 638 if (copied) 639 break; 640 return -EIO; 641 } 642 if (copy_to_user(dst, buf, retval)) 643 return -EFAULT; 644 copied += retval; 645 src += retval; 646 dst += retval; 647 len -= retval; 648 } 649 return copied; 650 } 651 652 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 653 { 654 int copied = 0; 655 656 while (len > 0) { 657 char buf[128]; 658 int this_len, retval; 659 660 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 661 if (copy_from_user(buf, src, this_len)) 662 return -EFAULT; 663 retval = ptrace_access_vm(tsk, dst, buf, this_len, 664 FOLL_FORCE | FOLL_WRITE); 665 if (!retval) { 666 if (copied) 667 break; 668 return -EIO; 669 } 670 copied += retval; 671 src += retval; 672 dst += retval; 673 len -= retval; 674 } 675 return copied; 676 } 677 678 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 679 { 680 unsigned flags; 681 int ret; 682 683 ret = check_ptrace_options(data); 684 if (ret) 685 return ret; 686 687 /* Avoid intermediate state when all opts are cleared */ 688 flags = child->ptrace; 689 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 690 flags |= (data << PT_OPT_FLAG_SHIFT); 691 child->ptrace = flags; 692 693 return 0; 694 } 695 696 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 697 { 698 unsigned long flags; 699 int error = -ESRCH; 700 701 if (lock_task_sighand(child, &flags)) { 702 error = -EINVAL; 703 if (likely(child->last_siginfo != NULL)) { 704 copy_siginfo(info, child->last_siginfo); 705 error = 0; 706 } 707 unlock_task_sighand(child, &flags); 708 } 709 return error; 710 } 711 712 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 713 { 714 unsigned long flags; 715 int error = -ESRCH; 716 717 if (lock_task_sighand(child, &flags)) { 718 error = -EINVAL; 719 if (likely(child->last_siginfo != NULL)) { 720 copy_siginfo(child->last_siginfo, info); 721 error = 0; 722 } 723 unlock_task_sighand(child, &flags); 724 } 725 return error; 726 } 727 728 static int ptrace_peek_siginfo(struct task_struct *child, 729 unsigned long addr, 730 unsigned long data) 731 { 732 struct ptrace_peeksiginfo_args arg; 733 struct sigpending *pending; 734 struct sigqueue *q; 735 int ret, i; 736 737 ret = copy_from_user(&arg, (void __user *) addr, 738 sizeof(struct ptrace_peeksiginfo_args)); 739 if (ret) 740 return -EFAULT; 741 742 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 743 return -EINVAL; /* unknown flags */ 744 745 if (arg.nr < 0) 746 return -EINVAL; 747 748 /* Ensure arg.off fits in an unsigned long */ 749 if (arg.off > ULONG_MAX) 750 return 0; 751 752 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 753 pending = &child->signal->shared_pending; 754 else 755 pending = &child->pending; 756 757 for (i = 0; i < arg.nr; ) { 758 kernel_siginfo_t info; 759 unsigned long off = arg.off + i; 760 bool found = false; 761 762 spin_lock_irq(&child->sighand->siglock); 763 list_for_each_entry(q, &pending->list, list) { 764 if (!off--) { 765 found = true; 766 copy_siginfo(&info, &q->info); 767 break; 768 } 769 } 770 spin_unlock_irq(&child->sighand->siglock); 771 772 if (!found) /* beyond the end of the list */ 773 break; 774 775 #ifdef CONFIG_COMPAT 776 if (unlikely(in_compat_syscall())) { 777 compat_siginfo_t __user *uinfo = compat_ptr(data); 778 779 if (copy_siginfo_to_user32(uinfo, &info)) { 780 ret = -EFAULT; 781 break; 782 } 783 784 } else 785 #endif 786 { 787 siginfo_t __user *uinfo = (siginfo_t __user *) data; 788 789 if (copy_siginfo_to_user(uinfo, &info)) { 790 ret = -EFAULT; 791 break; 792 } 793 } 794 795 data += sizeof(siginfo_t); 796 i++; 797 798 if (signal_pending(current)) 799 break; 800 801 cond_resched(); 802 } 803 804 if (i > 0) 805 return i; 806 807 return ret; 808 } 809 810 #ifdef CONFIG_RSEQ 811 static long ptrace_get_rseq_configuration(struct task_struct *task, 812 unsigned long size, void __user *data) 813 { 814 struct ptrace_rseq_configuration conf = { 815 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, 816 .rseq_abi_size = task->rseq_len, 817 .signature = task->rseq_sig, 818 .flags = 0, 819 }; 820 821 size = min_t(unsigned long, size, sizeof(conf)); 822 if (copy_to_user(data, &conf, size)) 823 return -EFAULT; 824 return sizeof(conf); 825 } 826 #endif 827 828 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 829 830 #ifdef PTRACE_SINGLEBLOCK 831 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 832 #else 833 #define is_singleblock(request) 0 834 #endif 835 836 #ifdef PTRACE_SYSEMU 837 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 838 #else 839 #define is_sysemu_singlestep(request) 0 840 #endif 841 842 static int ptrace_resume(struct task_struct *child, long request, 843 unsigned long data) 844 { 845 if (!valid_signal(data)) 846 return -EIO; 847 848 if (request == PTRACE_SYSCALL) 849 set_task_syscall_work(child, SYSCALL_TRACE); 850 else 851 clear_task_syscall_work(child, SYSCALL_TRACE); 852 853 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 854 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 855 set_task_syscall_work(child, SYSCALL_EMU); 856 else 857 clear_task_syscall_work(child, SYSCALL_EMU); 858 #endif 859 860 if (is_singleblock(request)) { 861 if (unlikely(!arch_has_block_step())) 862 return -EIO; 863 user_enable_block_step(child); 864 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 865 if (unlikely(!arch_has_single_step())) 866 return -EIO; 867 user_enable_single_step(child); 868 } else { 869 user_disable_single_step(child); 870 } 871 872 /* 873 * Change ->exit_code and ->state under siglock to avoid the race 874 * with wait_task_stopped() in between; a non-zero ->exit_code will 875 * wrongly look like another report from tracee. 876 * 877 * Note that we need siglock even if ->exit_code == data and/or this 878 * status was not reported yet, the new status must not be cleared by 879 * wait_task_stopped() after resume. 880 */ 881 spin_lock_irq(&child->sighand->siglock); 882 child->exit_code = data; 883 child->jobctl &= ~JOBCTL_TRACED; 884 wake_up_state(child, __TASK_TRACED); 885 spin_unlock_irq(&child->sighand->siglock); 886 887 return 0; 888 } 889 890 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 891 892 static const struct user_regset * 893 find_regset(const struct user_regset_view *view, unsigned int type) 894 { 895 const struct user_regset *regset; 896 int n; 897 898 for (n = 0; n < view->n; ++n) { 899 regset = view->regsets + n; 900 if (regset->core_note_type == type) 901 return regset; 902 } 903 904 return NULL; 905 } 906 907 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 908 struct iovec *kiov) 909 { 910 const struct user_regset_view *view = task_user_regset_view(task); 911 const struct user_regset *regset = find_regset(view, type); 912 int regset_no; 913 914 if (!regset || (kiov->iov_len % regset->size) != 0) 915 return -EINVAL; 916 917 regset_no = regset - view->regsets; 918 kiov->iov_len = min(kiov->iov_len, 919 (__kernel_size_t) (regset->n * regset->size)); 920 921 if (req == PTRACE_GETREGSET) 922 return copy_regset_to_user(task, view, regset_no, 0, 923 kiov->iov_len, kiov->iov_base); 924 else 925 return copy_regset_from_user(task, view, regset_no, 0, 926 kiov->iov_len, kiov->iov_base); 927 } 928 929 /* 930 * This is declared in linux/regset.h and defined in machine-dependent 931 * code. We put the export here, near the primary machine-neutral use, 932 * to ensure no machine forgets it. 933 */ 934 EXPORT_SYMBOL_GPL(task_user_regset_view); 935 936 static unsigned long 937 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 938 struct ptrace_syscall_info *info) 939 { 940 unsigned long args[ARRAY_SIZE(info->entry.args)]; 941 int i; 942 943 info->op = PTRACE_SYSCALL_INFO_ENTRY; 944 info->entry.nr = syscall_get_nr(child, regs); 945 syscall_get_arguments(child, regs, args); 946 for (i = 0; i < ARRAY_SIZE(args); i++) 947 info->entry.args[i] = args[i]; 948 949 /* args is the last field in struct ptrace_syscall_info.entry */ 950 return offsetofend(struct ptrace_syscall_info, entry.args); 951 } 952 953 static unsigned long 954 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 955 struct ptrace_syscall_info *info) 956 { 957 /* 958 * As struct ptrace_syscall_info.entry is currently a subset 959 * of struct ptrace_syscall_info.seccomp, it makes sense to 960 * initialize that subset using ptrace_get_syscall_info_entry(). 961 * This can be reconsidered in the future if these structures 962 * diverge significantly enough. 963 */ 964 ptrace_get_syscall_info_entry(child, regs, info); 965 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 966 info->seccomp.ret_data = child->ptrace_message; 967 968 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 969 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 970 } 971 972 static unsigned long 973 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 974 struct ptrace_syscall_info *info) 975 { 976 info->op = PTRACE_SYSCALL_INFO_EXIT; 977 info->exit.rval = syscall_get_error(child, regs); 978 info->exit.is_error = !!info->exit.rval; 979 if (!info->exit.is_error) 980 info->exit.rval = syscall_get_return_value(child, regs); 981 982 /* is_error is the last field in struct ptrace_syscall_info.exit */ 983 return offsetofend(struct ptrace_syscall_info, exit.is_error); 984 } 985 986 static int 987 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 988 void __user *datavp) 989 { 990 struct pt_regs *regs = task_pt_regs(child); 991 struct ptrace_syscall_info info = { 992 .op = PTRACE_SYSCALL_INFO_NONE, 993 .arch = syscall_get_arch(child), 994 .instruction_pointer = instruction_pointer(regs), 995 .stack_pointer = user_stack_pointer(regs), 996 }; 997 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 998 unsigned long write_size; 999 1000 /* 1001 * This does not need lock_task_sighand() to access 1002 * child->last_siginfo because ptrace_freeze_traced() 1003 * called earlier by ptrace_check_attach() ensures that 1004 * the tracee cannot go away and clear its last_siginfo. 1005 */ 1006 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 1007 case SIGTRAP | 0x80: 1008 switch (child->ptrace_message) { 1009 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 1010 actual_size = ptrace_get_syscall_info_entry(child, regs, 1011 &info); 1012 break; 1013 case PTRACE_EVENTMSG_SYSCALL_EXIT: 1014 actual_size = ptrace_get_syscall_info_exit(child, regs, 1015 &info); 1016 break; 1017 } 1018 break; 1019 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 1020 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 1021 &info); 1022 break; 1023 } 1024 1025 write_size = min(actual_size, user_size); 1026 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 1027 } 1028 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 1029 1030 int ptrace_request(struct task_struct *child, long request, 1031 unsigned long addr, unsigned long data) 1032 { 1033 bool seized = child->ptrace & PT_SEIZED; 1034 int ret = -EIO; 1035 kernel_siginfo_t siginfo, *si; 1036 void __user *datavp = (void __user *) data; 1037 unsigned long __user *datalp = datavp; 1038 unsigned long flags; 1039 1040 switch (request) { 1041 case PTRACE_PEEKTEXT: 1042 case PTRACE_PEEKDATA: 1043 return generic_ptrace_peekdata(child, addr, data); 1044 case PTRACE_POKETEXT: 1045 case PTRACE_POKEDATA: 1046 return generic_ptrace_pokedata(child, addr, data); 1047 1048 #ifdef PTRACE_OLDSETOPTIONS 1049 case PTRACE_OLDSETOPTIONS: 1050 #endif 1051 case PTRACE_SETOPTIONS: 1052 ret = ptrace_setoptions(child, data); 1053 break; 1054 case PTRACE_GETEVENTMSG: 1055 ret = put_user(child->ptrace_message, datalp); 1056 break; 1057 1058 case PTRACE_PEEKSIGINFO: 1059 ret = ptrace_peek_siginfo(child, addr, data); 1060 break; 1061 1062 case PTRACE_GETSIGINFO: 1063 ret = ptrace_getsiginfo(child, &siginfo); 1064 if (!ret) 1065 ret = copy_siginfo_to_user(datavp, &siginfo); 1066 break; 1067 1068 case PTRACE_SETSIGINFO: 1069 ret = copy_siginfo_from_user(&siginfo, datavp); 1070 if (!ret) 1071 ret = ptrace_setsiginfo(child, &siginfo); 1072 break; 1073 1074 case PTRACE_GETSIGMASK: { 1075 sigset_t *mask; 1076 1077 if (addr != sizeof(sigset_t)) { 1078 ret = -EINVAL; 1079 break; 1080 } 1081 1082 if (test_tsk_restore_sigmask(child)) 1083 mask = &child->saved_sigmask; 1084 else 1085 mask = &child->blocked; 1086 1087 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1088 ret = -EFAULT; 1089 else 1090 ret = 0; 1091 1092 break; 1093 } 1094 1095 case PTRACE_SETSIGMASK: { 1096 sigset_t new_set; 1097 1098 if (addr != sizeof(sigset_t)) { 1099 ret = -EINVAL; 1100 break; 1101 } 1102 1103 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1104 ret = -EFAULT; 1105 break; 1106 } 1107 1108 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1109 1110 /* 1111 * Every thread does recalc_sigpending() after resume, so 1112 * retarget_shared_pending() and recalc_sigpending() are not 1113 * called here. 1114 */ 1115 spin_lock_irq(&child->sighand->siglock); 1116 child->blocked = new_set; 1117 spin_unlock_irq(&child->sighand->siglock); 1118 1119 clear_tsk_restore_sigmask(child); 1120 1121 ret = 0; 1122 break; 1123 } 1124 1125 case PTRACE_INTERRUPT: 1126 /* 1127 * Stop tracee without any side-effect on signal or job 1128 * control. At least one trap is guaranteed to happen 1129 * after this request. If @child is already trapped, the 1130 * current trap is not disturbed and another trap will 1131 * happen after the current trap is ended with PTRACE_CONT. 1132 * 1133 * The actual trap might not be PTRACE_EVENT_STOP trap but 1134 * the pending condition is cleared regardless. 1135 */ 1136 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1137 break; 1138 1139 /* 1140 * INTERRUPT doesn't disturb existing trap sans one 1141 * exception. If ptracer issued LISTEN for the current 1142 * STOP, this INTERRUPT should clear LISTEN and re-trap 1143 * tracee into STOP. 1144 */ 1145 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1146 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1147 1148 unlock_task_sighand(child, &flags); 1149 ret = 0; 1150 break; 1151 1152 case PTRACE_LISTEN: 1153 /* 1154 * Listen for events. Tracee must be in STOP. It's not 1155 * resumed per-se but is not considered to be in TRACED by 1156 * wait(2) or ptrace(2). If an async event (e.g. group 1157 * stop state change) happens, tracee will enter STOP trap 1158 * again. Alternatively, ptracer can issue INTERRUPT to 1159 * finish listening and re-trap tracee into STOP. 1160 */ 1161 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1162 break; 1163 1164 si = child->last_siginfo; 1165 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1166 child->jobctl |= JOBCTL_LISTENING; 1167 /* 1168 * If NOTIFY is set, it means event happened between 1169 * start of this trap and now. Trigger re-trap. 1170 */ 1171 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1172 ptrace_signal_wake_up(child, true); 1173 ret = 0; 1174 } 1175 unlock_task_sighand(child, &flags); 1176 break; 1177 1178 case PTRACE_DETACH: /* detach a process that was attached. */ 1179 ret = ptrace_detach(child, data); 1180 break; 1181 1182 #ifdef CONFIG_BINFMT_ELF_FDPIC 1183 case PTRACE_GETFDPIC: { 1184 struct mm_struct *mm = get_task_mm(child); 1185 unsigned long tmp = 0; 1186 1187 ret = -ESRCH; 1188 if (!mm) 1189 break; 1190 1191 switch (addr) { 1192 case PTRACE_GETFDPIC_EXEC: 1193 tmp = mm->context.exec_fdpic_loadmap; 1194 break; 1195 case PTRACE_GETFDPIC_INTERP: 1196 tmp = mm->context.interp_fdpic_loadmap; 1197 break; 1198 default: 1199 break; 1200 } 1201 mmput(mm); 1202 1203 ret = put_user(tmp, datalp); 1204 break; 1205 } 1206 #endif 1207 1208 case PTRACE_SINGLESTEP: 1209 #ifdef PTRACE_SINGLEBLOCK 1210 case PTRACE_SINGLEBLOCK: 1211 #endif 1212 #ifdef PTRACE_SYSEMU 1213 case PTRACE_SYSEMU: 1214 case PTRACE_SYSEMU_SINGLESTEP: 1215 #endif 1216 case PTRACE_SYSCALL: 1217 case PTRACE_CONT: 1218 return ptrace_resume(child, request, data); 1219 1220 case PTRACE_KILL: 1221 send_sig_info(SIGKILL, SEND_SIG_NOINFO, child); 1222 return 0; 1223 1224 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1225 case PTRACE_GETREGSET: 1226 case PTRACE_SETREGSET: { 1227 struct iovec kiov; 1228 struct iovec __user *uiov = datavp; 1229 1230 if (!access_ok(uiov, sizeof(*uiov))) 1231 return -EFAULT; 1232 1233 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1234 __get_user(kiov.iov_len, &uiov->iov_len)) 1235 return -EFAULT; 1236 1237 ret = ptrace_regset(child, request, addr, &kiov); 1238 if (!ret) 1239 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1240 break; 1241 } 1242 1243 case PTRACE_GET_SYSCALL_INFO: 1244 ret = ptrace_get_syscall_info(child, addr, datavp); 1245 break; 1246 #endif 1247 1248 case PTRACE_SECCOMP_GET_FILTER: 1249 ret = seccomp_get_filter(child, addr, datavp); 1250 break; 1251 1252 case PTRACE_SECCOMP_GET_METADATA: 1253 ret = seccomp_get_metadata(child, addr, datavp); 1254 break; 1255 1256 #ifdef CONFIG_RSEQ 1257 case PTRACE_GET_RSEQ_CONFIGURATION: 1258 ret = ptrace_get_rseq_configuration(child, addr, datavp); 1259 break; 1260 #endif 1261 1262 default: 1263 break; 1264 } 1265 1266 return ret; 1267 } 1268 1269 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1270 unsigned long, data) 1271 { 1272 struct task_struct *child; 1273 long ret; 1274 1275 if (request == PTRACE_TRACEME) { 1276 ret = ptrace_traceme(); 1277 goto out; 1278 } 1279 1280 child = find_get_task_by_vpid(pid); 1281 if (!child) { 1282 ret = -ESRCH; 1283 goto out; 1284 } 1285 1286 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1287 ret = ptrace_attach(child, request, addr, data); 1288 goto out_put_task_struct; 1289 } 1290 1291 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1292 request == PTRACE_INTERRUPT); 1293 if (ret < 0) 1294 goto out_put_task_struct; 1295 1296 ret = arch_ptrace(child, request, addr, data); 1297 if (ret || request != PTRACE_DETACH) 1298 ptrace_unfreeze_traced(child); 1299 1300 out_put_task_struct: 1301 put_task_struct(child); 1302 out: 1303 return ret; 1304 } 1305 1306 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1307 unsigned long data) 1308 { 1309 unsigned long tmp; 1310 int copied; 1311 1312 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1313 if (copied != sizeof(tmp)) 1314 return -EIO; 1315 return put_user(tmp, (unsigned long __user *)data); 1316 } 1317 1318 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1319 unsigned long data) 1320 { 1321 int copied; 1322 1323 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1324 FOLL_FORCE | FOLL_WRITE); 1325 return (copied == sizeof(data)) ? 0 : -EIO; 1326 } 1327 1328 #if defined CONFIG_COMPAT 1329 1330 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1331 compat_ulong_t addr, compat_ulong_t data) 1332 { 1333 compat_ulong_t __user *datap = compat_ptr(data); 1334 compat_ulong_t word; 1335 kernel_siginfo_t siginfo; 1336 int ret; 1337 1338 switch (request) { 1339 case PTRACE_PEEKTEXT: 1340 case PTRACE_PEEKDATA: 1341 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1342 FOLL_FORCE); 1343 if (ret != sizeof(word)) 1344 ret = -EIO; 1345 else 1346 ret = put_user(word, datap); 1347 break; 1348 1349 case PTRACE_POKETEXT: 1350 case PTRACE_POKEDATA: 1351 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1352 FOLL_FORCE | FOLL_WRITE); 1353 ret = (ret != sizeof(data) ? -EIO : 0); 1354 break; 1355 1356 case PTRACE_GETEVENTMSG: 1357 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1358 break; 1359 1360 case PTRACE_GETSIGINFO: 1361 ret = ptrace_getsiginfo(child, &siginfo); 1362 if (!ret) 1363 ret = copy_siginfo_to_user32( 1364 (struct compat_siginfo __user *) datap, 1365 &siginfo); 1366 break; 1367 1368 case PTRACE_SETSIGINFO: 1369 ret = copy_siginfo_from_user32( 1370 &siginfo, (struct compat_siginfo __user *) datap); 1371 if (!ret) 1372 ret = ptrace_setsiginfo(child, &siginfo); 1373 break; 1374 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1375 case PTRACE_GETREGSET: 1376 case PTRACE_SETREGSET: 1377 { 1378 struct iovec kiov; 1379 struct compat_iovec __user *uiov = 1380 (struct compat_iovec __user *) datap; 1381 compat_uptr_t ptr; 1382 compat_size_t len; 1383 1384 if (!access_ok(uiov, sizeof(*uiov))) 1385 return -EFAULT; 1386 1387 if (__get_user(ptr, &uiov->iov_base) || 1388 __get_user(len, &uiov->iov_len)) 1389 return -EFAULT; 1390 1391 kiov.iov_base = compat_ptr(ptr); 1392 kiov.iov_len = len; 1393 1394 ret = ptrace_regset(child, request, addr, &kiov); 1395 if (!ret) 1396 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1397 break; 1398 } 1399 #endif 1400 1401 default: 1402 ret = ptrace_request(child, request, addr, data); 1403 } 1404 1405 return ret; 1406 } 1407 1408 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1409 compat_long_t, addr, compat_long_t, data) 1410 { 1411 struct task_struct *child; 1412 long ret; 1413 1414 if (request == PTRACE_TRACEME) { 1415 ret = ptrace_traceme(); 1416 goto out; 1417 } 1418 1419 child = find_get_task_by_vpid(pid); 1420 if (!child) { 1421 ret = -ESRCH; 1422 goto out; 1423 } 1424 1425 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1426 ret = ptrace_attach(child, request, addr, data); 1427 goto out_put_task_struct; 1428 } 1429 1430 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1431 request == PTRACE_INTERRUPT); 1432 if (!ret) { 1433 ret = compat_arch_ptrace(child, request, addr, data); 1434 if (ret || request != PTRACE_DETACH) 1435 ptrace_unfreeze_traced(child); 1436 } 1437 1438 out_put_task_struct: 1439 put_task_struct(child); 1440 out: 1441 return ret; 1442 } 1443 #endif /* CONFIG_COMPAT */ 1444