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 #include <linux/syscall_user_dispatch.h> 36 37 #include <asm/syscall.h> /* for syscall_get_* */ 38 39 /* 40 * Access another process' address space via ptrace. 41 * Source/target buffer must be kernel space, 42 * Do not walk the page table directly, use get_user_pages 43 */ 44 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr, 45 void *buf, int len, unsigned int gup_flags) 46 { 47 struct mm_struct *mm; 48 int ret; 49 50 mm = get_task_mm(tsk); 51 if (!mm) 52 return 0; 53 54 if (!tsk->ptrace || 55 (current != tsk->parent) || 56 ((get_dumpable(mm) != SUID_DUMP_USER) && 57 !ptracer_capable(tsk, mm->user_ns))) { 58 mmput(mm); 59 return 0; 60 } 61 62 ret = access_remote_vm(mm, addr, buf, len, gup_flags); 63 mmput(mm); 64 65 return ret; 66 } 67 68 69 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent, 70 const struct cred *ptracer_cred) 71 { 72 BUG_ON(!list_empty(&child->ptrace_entry)); 73 list_add(&child->ptrace_entry, &new_parent->ptraced); 74 child->parent = new_parent; 75 child->ptracer_cred = get_cred(ptracer_cred); 76 } 77 78 /* 79 * ptrace a task: make the debugger its new parent and 80 * move it to the ptrace list. 81 * 82 * Must be called with the tasklist lock write-held. 83 */ 84 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent) 85 { 86 __ptrace_link(child, new_parent, current_cred()); 87 } 88 89 /** 90 * __ptrace_unlink - unlink ptracee and restore its execution state 91 * @child: ptracee to be unlinked 92 * 93 * Remove @child from the ptrace list, move it back to the original parent, 94 * and restore the execution state so that it conforms to the group stop 95 * state. 96 * 97 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer 98 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between 99 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. 100 * If the ptracer is exiting, the ptracee can be in any state. 101 * 102 * After detach, the ptracee should be in a state which conforms to the 103 * group stop. If the group is stopped or in the process of stopping, the 104 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken 105 * up from TASK_TRACED. 106 * 107 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, 108 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar 109 * to but in the opposite direction of what happens while attaching to a 110 * stopped task. However, in this direction, the intermediate RUNNING 111 * state is not hidden even from the current ptracer and if it immediately 112 * re-attaches and performs a WNOHANG wait(2), it may fail. 113 * 114 * CONTEXT: 115 * write_lock_irq(tasklist_lock) 116 */ 117 void __ptrace_unlink(struct task_struct *child) 118 { 119 const struct cred *old_cred; 120 BUG_ON(!child->ptrace); 121 122 clear_task_syscall_work(child, SYSCALL_TRACE); 123 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 124 clear_task_syscall_work(child, SYSCALL_EMU); 125 #endif 126 127 child->parent = child->real_parent; 128 list_del_init(&child->ptrace_entry); 129 old_cred = child->ptracer_cred; 130 child->ptracer_cred = NULL; 131 put_cred(old_cred); 132 133 spin_lock(&child->sighand->siglock); 134 child->ptrace = 0; 135 /* 136 * Clear all pending traps and TRAPPING. TRAPPING should be 137 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. 138 */ 139 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); 140 task_clear_jobctl_trapping(child); 141 142 /* 143 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and 144 * @child isn't dead. 145 */ 146 if (!(child->flags & PF_EXITING) && 147 (child->signal->flags & SIGNAL_STOP_STOPPED || 148 child->signal->group_stop_count)) 149 child->jobctl |= JOBCTL_STOP_PENDING; 150 151 /* 152 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick 153 * @child in the butt. Note that @resume should be used iff @child 154 * is in TASK_TRACED; otherwise, we might unduly disrupt 155 * TASK_KILLABLE sleeps. 156 */ 157 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) 158 ptrace_signal_wake_up(child, true); 159 160 spin_unlock(&child->sighand->siglock); 161 } 162 163 static bool looks_like_a_spurious_pid(struct task_struct *task) 164 { 165 if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP)) 166 return false; 167 168 if (task_pid_vnr(task) == task->ptrace_message) 169 return false; 170 /* 171 * The tracee changed its pid but the PTRACE_EVENT_EXEC event 172 * was not wait()'ed, most probably debugger targets the old 173 * leader which was destroyed in de_thread(). 174 */ 175 return true; 176 } 177 178 /* 179 * Ensure that nothing can wake it up, even SIGKILL 180 * 181 * A task is switched to this state while a ptrace operation is in progress; 182 * such that the ptrace operation is uninterruptible. 183 */ 184 static bool ptrace_freeze_traced(struct task_struct *task) 185 { 186 bool ret = false; 187 188 /* Lockless, nobody but us can set this flag */ 189 if (task->jobctl & JOBCTL_LISTENING) 190 return ret; 191 192 spin_lock_irq(&task->sighand->siglock); 193 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) && 194 !__fatal_signal_pending(task)) { 195 task->jobctl |= JOBCTL_PTRACE_FROZEN; 196 ret = true; 197 } 198 spin_unlock_irq(&task->sighand->siglock); 199 200 return ret; 201 } 202 203 static void ptrace_unfreeze_traced(struct task_struct *task) 204 { 205 unsigned long flags; 206 207 /* 208 * The child may be awake and may have cleared 209 * JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will 210 * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew. 211 */ 212 if (lock_task_sighand(task, &flags)) { 213 task->jobctl &= ~JOBCTL_PTRACE_FROZEN; 214 if (__fatal_signal_pending(task)) { 215 task->jobctl &= ~JOBCTL_TRACED; 216 wake_up_state(task, __TASK_TRACED); 217 } 218 unlock_task_sighand(task, &flags); 219 } 220 } 221 222 /** 223 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 224 * @child: ptracee to check for 225 * @ignore_state: don't check whether @child is currently %TASK_TRACED 226 * 227 * Check whether @child is being ptraced by %current and ready for further 228 * ptrace operations. If @ignore_state is %false, @child also should be in 229 * %TASK_TRACED state and on return the child is guaranteed to be traced 230 * and not executing. If @ignore_state is %true, @child can be in any 231 * state. 232 * 233 * CONTEXT: 234 * Grabs and releases tasklist_lock and @child->sighand->siglock. 235 * 236 * RETURNS: 237 * 0 on success, -ESRCH if %child is not ready. 238 */ 239 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 240 { 241 int ret = -ESRCH; 242 243 /* 244 * We take the read lock around doing both checks to close a 245 * possible race where someone else was tracing our child and 246 * detached between these two checks. After this locked check, 247 * we are sure that this is our traced child and that can only 248 * be changed by us so it's not changing right after this. 249 */ 250 read_lock(&tasklist_lock); 251 if (child->ptrace && child->parent == current) { 252 /* 253 * child->sighand can't be NULL, release_task() 254 * does ptrace_unlink() before __exit_signal(). 255 */ 256 if (ignore_state || ptrace_freeze_traced(child)) 257 ret = 0; 258 } 259 read_unlock(&tasklist_lock); 260 261 if (!ret && !ignore_state && 262 WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN))) 263 ret = -ESRCH; 264 265 return ret; 266 } 267 268 static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 269 { 270 if (mode & PTRACE_MODE_NOAUDIT) 271 return ns_capable_noaudit(ns, CAP_SYS_PTRACE); 272 return ns_capable(ns, CAP_SYS_PTRACE); 273 } 274 275 /* Returns 0 on success, -errno on denial. */ 276 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 277 { 278 const struct cred *cred = current_cred(), *tcred; 279 struct mm_struct *mm; 280 kuid_t caller_uid; 281 kgid_t caller_gid; 282 283 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) { 284 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n"); 285 return -EPERM; 286 } 287 288 /* May we inspect the given task? 289 * This check is used both for attaching with ptrace 290 * and for allowing access to sensitive information in /proc. 291 * 292 * ptrace_attach denies several cases that /proc allows 293 * because setting up the necessary parent/child relationship 294 * or halting the specified task is impossible. 295 */ 296 297 /* Don't let security modules deny introspection */ 298 if (same_thread_group(task, current)) 299 return 0; 300 rcu_read_lock(); 301 if (mode & PTRACE_MODE_FSCREDS) { 302 caller_uid = cred->fsuid; 303 caller_gid = cred->fsgid; 304 } else { 305 /* 306 * Using the euid would make more sense here, but something 307 * in userland might rely on the old behavior, and this 308 * shouldn't be a security problem since 309 * PTRACE_MODE_REALCREDS implies that the caller explicitly 310 * used a syscall that requests access to another process 311 * (and not a filesystem syscall to procfs). 312 */ 313 caller_uid = cred->uid; 314 caller_gid = cred->gid; 315 } 316 tcred = __task_cred(task); 317 if (uid_eq(caller_uid, tcred->euid) && 318 uid_eq(caller_uid, tcred->suid) && 319 uid_eq(caller_uid, tcred->uid) && 320 gid_eq(caller_gid, tcred->egid) && 321 gid_eq(caller_gid, tcred->sgid) && 322 gid_eq(caller_gid, tcred->gid)) 323 goto ok; 324 if (ptrace_has_cap(tcred->user_ns, mode)) 325 goto ok; 326 rcu_read_unlock(); 327 return -EPERM; 328 ok: 329 rcu_read_unlock(); 330 /* 331 * If a task drops privileges and becomes nondumpable (through a syscall 332 * like setresuid()) while we are trying to access it, we must ensure 333 * that the dumpability is read after the credentials; otherwise, 334 * we may be able to attach to a task that we shouldn't be able to 335 * attach to (as if the task had dropped privileges without becoming 336 * nondumpable). 337 * Pairs with a write barrier in commit_creds(). 338 */ 339 smp_rmb(); 340 mm = task->mm; 341 if (mm && 342 ((get_dumpable(mm) != SUID_DUMP_USER) && 343 !ptrace_has_cap(mm->user_ns, mode))) 344 return -EPERM; 345 346 return security_ptrace_access_check(task, mode); 347 } 348 349 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 350 { 351 int err; 352 task_lock(task); 353 err = __ptrace_may_access(task, mode); 354 task_unlock(task); 355 return !err; 356 } 357 358 static int check_ptrace_options(unsigned long data) 359 { 360 if (data & ~(unsigned long)PTRACE_O_MASK) 361 return -EINVAL; 362 363 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 364 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 365 !IS_ENABLED(CONFIG_SECCOMP)) 366 return -EINVAL; 367 368 if (!capable(CAP_SYS_ADMIN)) 369 return -EPERM; 370 371 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 372 current->ptrace & PT_SUSPEND_SECCOMP) 373 return -EPERM; 374 } 375 return 0; 376 } 377 378 static int ptrace_attach(struct task_struct *task, long request, 379 unsigned long addr, 380 unsigned long flags) 381 { 382 bool seize = (request == PTRACE_SEIZE); 383 int retval; 384 385 retval = -EIO; 386 if (seize) { 387 if (addr != 0) 388 goto out; 389 /* 390 * This duplicates the check in check_ptrace_options() because 391 * ptrace_attach() and ptrace_setoptions() have historically 392 * used different error codes for unknown ptrace options. 393 */ 394 if (flags & ~(unsigned long)PTRACE_O_MASK) 395 goto out; 396 retval = check_ptrace_options(flags); 397 if (retval) 398 return retval; 399 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 400 } else { 401 flags = PT_PTRACED; 402 } 403 404 audit_ptrace(task); 405 406 retval = -EPERM; 407 if (unlikely(task->flags & PF_KTHREAD)) 408 goto out; 409 if (same_thread_group(task, current)) 410 goto out; 411 412 /* 413 * Protect exec's credential calculations against our interference; 414 * SUID, SGID and LSM creds get determined differently 415 * under ptrace. 416 */ 417 retval = -ERESTARTNOINTR; 418 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 419 goto out; 420 421 task_lock(task); 422 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); 423 task_unlock(task); 424 if (retval) 425 goto unlock_creds; 426 427 write_lock_irq(&tasklist_lock); 428 retval = -EPERM; 429 if (unlikely(task->exit_state)) 430 goto unlock_tasklist; 431 if (task->ptrace) 432 goto unlock_tasklist; 433 434 task->ptrace = flags; 435 436 ptrace_link(task, current); 437 438 /* SEIZE doesn't trap tracee on attach */ 439 if (!seize) 440 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 441 442 spin_lock(&task->sighand->siglock); 443 444 /* 445 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 446 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 447 * will be cleared if the child completes the transition or any 448 * event which clears the group stop states happens. We'll wait 449 * for the transition to complete before returning from this 450 * function. 451 * 452 * This hides STOPPED -> RUNNING -> TRACED transition from the 453 * attaching thread but a different thread in the same group can 454 * still observe the transient RUNNING state. IOW, if another 455 * thread's WNOHANG wait(2) on the stopped tracee races against 456 * ATTACH, the wait(2) may fail due to the transient RUNNING. 457 * 458 * The following task_is_stopped() test is safe as both transitions 459 * in and out of STOPPED are protected by siglock. 460 */ 461 if (task_is_stopped(task) && 462 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) { 463 task->jobctl &= ~JOBCTL_STOPPED; 464 signal_wake_up_state(task, __TASK_STOPPED); 465 } 466 467 spin_unlock(&task->sighand->siglock); 468 469 retval = 0; 470 unlock_tasklist: 471 write_unlock_irq(&tasklist_lock); 472 unlock_creds: 473 mutex_unlock(&task->signal->cred_guard_mutex); 474 out: 475 if (!retval) { 476 /* 477 * We do not bother to change retval or clear JOBCTL_TRAPPING 478 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 479 * not return to user-mode, it will exit and clear this bit in 480 * __ptrace_unlink() if it wasn't already cleared by the tracee; 481 * and until then nobody can ptrace this task. 482 */ 483 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 484 proc_ptrace_connector(task, PTRACE_ATTACH); 485 } 486 487 return retval; 488 } 489 490 /** 491 * ptrace_traceme -- helper for PTRACE_TRACEME 492 * 493 * Performs checks and sets PT_PTRACED. 494 * Should be used by all ptrace implementations for PTRACE_TRACEME. 495 */ 496 static int ptrace_traceme(void) 497 { 498 int ret = -EPERM; 499 500 write_lock_irq(&tasklist_lock); 501 /* Are we already being traced? */ 502 if (!current->ptrace) { 503 ret = security_ptrace_traceme(current->parent); 504 /* 505 * Check PF_EXITING to ensure ->real_parent has not passed 506 * exit_ptrace(). Otherwise we don't report the error but 507 * pretend ->real_parent untraces us right after return. 508 */ 509 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 510 current->ptrace = PT_PTRACED; 511 ptrace_link(current, current->real_parent); 512 } 513 } 514 write_unlock_irq(&tasklist_lock); 515 516 return ret; 517 } 518 519 /* 520 * Called with irqs disabled, returns true if childs should reap themselves. 521 */ 522 static int ignoring_children(struct sighand_struct *sigh) 523 { 524 int ret; 525 spin_lock(&sigh->siglock); 526 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 527 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 528 spin_unlock(&sigh->siglock); 529 return ret; 530 } 531 532 /* 533 * Called with tasklist_lock held for writing. 534 * Unlink a traced task, and clean it up if it was a traced zombie. 535 * Return true if it needs to be reaped with release_task(). 536 * (We can't call release_task() here because we already hold tasklist_lock.) 537 * 538 * If it's a zombie, our attachedness prevented normal parent notification 539 * or self-reaping. Do notification now if it would have happened earlier. 540 * If it should reap itself, return true. 541 * 542 * If it's our own child, there is no notification to do. But if our normal 543 * children self-reap, then this child was prevented by ptrace and we must 544 * reap it now, in that case we must also wake up sub-threads sleeping in 545 * do_wait(). 546 */ 547 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 548 { 549 bool dead; 550 551 __ptrace_unlink(p); 552 553 if (p->exit_state != EXIT_ZOMBIE) 554 return false; 555 556 dead = !thread_group_leader(p); 557 558 if (!dead && thread_group_empty(p)) { 559 if (!same_thread_group(p->real_parent, tracer)) 560 dead = do_notify_parent(p, p->exit_signal); 561 else if (ignoring_children(tracer->sighand)) { 562 __wake_up_parent(p, tracer); 563 dead = true; 564 } 565 } 566 /* Mark it as in the process of being reaped. */ 567 if (dead) 568 p->exit_state = EXIT_DEAD; 569 return dead; 570 } 571 572 static int ptrace_detach(struct task_struct *child, unsigned int data) 573 { 574 if (!valid_signal(data)) 575 return -EIO; 576 577 /* Architecture-specific hardware disable .. */ 578 ptrace_disable(child); 579 580 write_lock_irq(&tasklist_lock); 581 /* 582 * We rely on ptrace_freeze_traced(). It can't be killed and 583 * untraced by another thread, it can't be a zombie. 584 */ 585 WARN_ON(!child->ptrace || child->exit_state); 586 /* 587 * tasklist_lock avoids the race with wait_task_stopped(), see 588 * the comment in ptrace_resume(). 589 */ 590 child->exit_code = data; 591 __ptrace_detach(current, child); 592 write_unlock_irq(&tasklist_lock); 593 594 proc_ptrace_connector(child, PTRACE_DETACH); 595 596 return 0; 597 } 598 599 /* 600 * Detach all tasks we were using ptrace on. Called with tasklist held 601 * for writing. 602 */ 603 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 604 { 605 struct task_struct *p, *n; 606 607 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 608 if (unlikely(p->ptrace & PT_EXITKILL)) 609 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 610 611 if (__ptrace_detach(tracer, p)) 612 list_add(&p->ptrace_entry, dead); 613 } 614 } 615 616 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 617 { 618 int copied = 0; 619 620 while (len > 0) { 621 char buf[128]; 622 int this_len, retval; 623 624 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 625 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 626 627 if (!retval) { 628 if (copied) 629 break; 630 return -EIO; 631 } 632 if (copy_to_user(dst, buf, retval)) 633 return -EFAULT; 634 copied += retval; 635 src += retval; 636 dst += retval; 637 len -= retval; 638 } 639 return copied; 640 } 641 642 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 643 { 644 int copied = 0; 645 646 while (len > 0) { 647 char buf[128]; 648 int this_len, retval; 649 650 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 651 if (copy_from_user(buf, src, this_len)) 652 return -EFAULT; 653 retval = ptrace_access_vm(tsk, dst, buf, this_len, 654 FOLL_FORCE | FOLL_WRITE); 655 if (!retval) { 656 if (copied) 657 break; 658 return -EIO; 659 } 660 copied += retval; 661 src += retval; 662 dst += retval; 663 len -= retval; 664 } 665 return copied; 666 } 667 668 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 669 { 670 unsigned flags; 671 int ret; 672 673 ret = check_ptrace_options(data); 674 if (ret) 675 return ret; 676 677 /* Avoid intermediate state when all opts are cleared */ 678 flags = child->ptrace; 679 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 680 flags |= (data << PT_OPT_FLAG_SHIFT); 681 child->ptrace = flags; 682 683 return 0; 684 } 685 686 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 687 { 688 unsigned long flags; 689 int error = -ESRCH; 690 691 if (lock_task_sighand(child, &flags)) { 692 error = -EINVAL; 693 if (likely(child->last_siginfo != NULL)) { 694 copy_siginfo(info, child->last_siginfo); 695 error = 0; 696 } 697 unlock_task_sighand(child, &flags); 698 } 699 return error; 700 } 701 702 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 703 { 704 unsigned long flags; 705 int error = -ESRCH; 706 707 if (lock_task_sighand(child, &flags)) { 708 error = -EINVAL; 709 if (likely(child->last_siginfo != NULL)) { 710 copy_siginfo(child->last_siginfo, info); 711 error = 0; 712 } 713 unlock_task_sighand(child, &flags); 714 } 715 return error; 716 } 717 718 static int ptrace_peek_siginfo(struct task_struct *child, 719 unsigned long addr, 720 unsigned long data) 721 { 722 struct ptrace_peeksiginfo_args arg; 723 struct sigpending *pending; 724 struct sigqueue *q; 725 int ret, i; 726 727 ret = copy_from_user(&arg, (void __user *) addr, 728 sizeof(struct ptrace_peeksiginfo_args)); 729 if (ret) 730 return -EFAULT; 731 732 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 733 return -EINVAL; /* unknown flags */ 734 735 if (arg.nr < 0) 736 return -EINVAL; 737 738 /* Ensure arg.off fits in an unsigned long */ 739 if (arg.off > ULONG_MAX) 740 return 0; 741 742 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 743 pending = &child->signal->shared_pending; 744 else 745 pending = &child->pending; 746 747 for (i = 0; i < arg.nr; ) { 748 kernel_siginfo_t info; 749 unsigned long off = arg.off + i; 750 bool found = false; 751 752 spin_lock_irq(&child->sighand->siglock); 753 list_for_each_entry(q, &pending->list, list) { 754 if (!off--) { 755 found = true; 756 copy_siginfo(&info, &q->info); 757 break; 758 } 759 } 760 spin_unlock_irq(&child->sighand->siglock); 761 762 if (!found) /* beyond the end of the list */ 763 break; 764 765 #ifdef CONFIG_COMPAT 766 if (unlikely(in_compat_syscall())) { 767 compat_siginfo_t __user *uinfo = compat_ptr(data); 768 769 if (copy_siginfo_to_user32(uinfo, &info)) { 770 ret = -EFAULT; 771 break; 772 } 773 774 } else 775 #endif 776 { 777 siginfo_t __user *uinfo = (siginfo_t __user *) data; 778 779 if (copy_siginfo_to_user(uinfo, &info)) { 780 ret = -EFAULT; 781 break; 782 } 783 } 784 785 data += sizeof(siginfo_t); 786 i++; 787 788 if (signal_pending(current)) 789 break; 790 791 cond_resched(); 792 } 793 794 if (i > 0) 795 return i; 796 797 return ret; 798 } 799 800 #ifdef CONFIG_RSEQ 801 static long ptrace_get_rseq_configuration(struct task_struct *task, 802 unsigned long size, void __user *data) 803 { 804 struct ptrace_rseq_configuration conf = { 805 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, 806 .rseq_abi_size = task->rseq_len, 807 .signature = task->rseq_sig, 808 .flags = 0, 809 }; 810 811 size = min_t(unsigned long, size, sizeof(conf)); 812 if (copy_to_user(data, &conf, size)) 813 return -EFAULT; 814 return sizeof(conf); 815 } 816 #endif 817 818 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 819 820 #ifdef PTRACE_SINGLEBLOCK 821 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 822 #else 823 #define is_singleblock(request) 0 824 #endif 825 826 #ifdef PTRACE_SYSEMU 827 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 828 #else 829 #define is_sysemu_singlestep(request) 0 830 #endif 831 832 static int ptrace_resume(struct task_struct *child, long request, 833 unsigned long data) 834 { 835 if (!valid_signal(data)) 836 return -EIO; 837 838 if (request == PTRACE_SYSCALL) 839 set_task_syscall_work(child, SYSCALL_TRACE); 840 else 841 clear_task_syscall_work(child, SYSCALL_TRACE); 842 843 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 844 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 845 set_task_syscall_work(child, SYSCALL_EMU); 846 else 847 clear_task_syscall_work(child, SYSCALL_EMU); 848 #endif 849 850 if (is_singleblock(request)) { 851 if (unlikely(!arch_has_block_step())) 852 return -EIO; 853 user_enable_block_step(child); 854 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 855 if (unlikely(!arch_has_single_step())) 856 return -EIO; 857 user_enable_single_step(child); 858 } else { 859 user_disable_single_step(child); 860 } 861 862 /* 863 * Change ->exit_code and ->state under siglock to avoid the race 864 * with wait_task_stopped() in between; a non-zero ->exit_code will 865 * wrongly look like another report from tracee. 866 * 867 * Note that we need siglock even if ->exit_code == data and/or this 868 * status was not reported yet, the new status must not be cleared by 869 * wait_task_stopped() after resume. 870 */ 871 spin_lock_irq(&child->sighand->siglock); 872 child->exit_code = data; 873 child->jobctl &= ~JOBCTL_TRACED; 874 wake_up_state(child, __TASK_TRACED); 875 spin_unlock_irq(&child->sighand->siglock); 876 877 return 0; 878 } 879 880 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 881 882 static const struct user_regset * 883 find_regset(const struct user_regset_view *view, unsigned int type) 884 { 885 const struct user_regset *regset; 886 int n; 887 888 for (n = 0; n < view->n; ++n) { 889 regset = view->regsets + n; 890 if (regset->core_note_type == type) 891 return regset; 892 } 893 894 return NULL; 895 } 896 897 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 898 struct iovec *kiov) 899 { 900 const struct user_regset_view *view = task_user_regset_view(task); 901 const struct user_regset *regset = find_regset(view, type); 902 int regset_no; 903 904 if (!regset || (kiov->iov_len % regset->size) != 0) 905 return -EINVAL; 906 907 regset_no = regset - view->regsets; 908 kiov->iov_len = min(kiov->iov_len, 909 (__kernel_size_t) (regset->n * regset->size)); 910 911 if (req == PTRACE_GETREGSET) 912 return copy_regset_to_user(task, view, regset_no, 0, 913 kiov->iov_len, kiov->iov_base); 914 else 915 return copy_regset_from_user(task, view, regset_no, 0, 916 kiov->iov_len, kiov->iov_base); 917 } 918 919 /* 920 * This is declared in linux/regset.h and defined in machine-dependent 921 * code. We put the export here, near the primary machine-neutral use, 922 * to ensure no machine forgets it. 923 */ 924 EXPORT_SYMBOL_GPL(task_user_regset_view); 925 926 static unsigned long 927 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 928 struct ptrace_syscall_info *info) 929 { 930 unsigned long args[ARRAY_SIZE(info->entry.args)]; 931 int i; 932 933 info->op = PTRACE_SYSCALL_INFO_ENTRY; 934 info->entry.nr = syscall_get_nr(child, regs); 935 syscall_get_arguments(child, regs, args); 936 for (i = 0; i < ARRAY_SIZE(args); i++) 937 info->entry.args[i] = args[i]; 938 939 /* args is the last field in struct ptrace_syscall_info.entry */ 940 return offsetofend(struct ptrace_syscall_info, entry.args); 941 } 942 943 static unsigned long 944 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 945 struct ptrace_syscall_info *info) 946 { 947 /* 948 * As struct ptrace_syscall_info.entry is currently a subset 949 * of struct ptrace_syscall_info.seccomp, it makes sense to 950 * initialize that subset using ptrace_get_syscall_info_entry(). 951 * This can be reconsidered in the future if these structures 952 * diverge significantly enough. 953 */ 954 ptrace_get_syscall_info_entry(child, regs, info); 955 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 956 info->seccomp.ret_data = child->ptrace_message; 957 958 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 959 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 960 } 961 962 static unsigned long 963 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 964 struct ptrace_syscall_info *info) 965 { 966 info->op = PTRACE_SYSCALL_INFO_EXIT; 967 info->exit.rval = syscall_get_error(child, regs); 968 info->exit.is_error = !!info->exit.rval; 969 if (!info->exit.is_error) 970 info->exit.rval = syscall_get_return_value(child, regs); 971 972 /* is_error is the last field in struct ptrace_syscall_info.exit */ 973 return offsetofend(struct ptrace_syscall_info, exit.is_error); 974 } 975 976 static int 977 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 978 void __user *datavp) 979 { 980 struct pt_regs *regs = task_pt_regs(child); 981 struct ptrace_syscall_info info = { 982 .op = PTRACE_SYSCALL_INFO_NONE, 983 .arch = syscall_get_arch(child), 984 .instruction_pointer = instruction_pointer(regs), 985 .stack_pointer = user_stack_pointer(regs), 986 }; 987 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 988 unsigned long write_size; 989 990 /* 991 * This does not need lock_task_sighand() to access 992 * child->last_siginfo because ptrace_freeze_traced() 993 * called earlier by ptrace_check_attach() ensures that 994 * the tracee cannot go away and clear its last_siginfo. 995 */ 996 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 997 case SIGTRAP | 0x80: 998 switch (child->ptrace_message) { 999 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 1000 actual_size = ptrace_get_syscall_info_entry(child, regs, 1001 &info); 1002 break; 1003 case PTRACE_EVENTMSG_SYSCALL_EXIT: 1004 actual_size = ptrace_get_syscall_info_exit(child, regs, 1005 &info); 1006 break; 1007 } 1008 break; 1009 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 1010 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 1011 &info); 1012 break; 1013 } 1014 1015 write_size = min(actual_size, user_size); 1016 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 1017 } 1018 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 1019 1020 int ptrace_request(struct task_struct *child, long request, 1021 unsigned long addr, unsigned long data) 1022 { 1023 bool seized = child->ptrace & PT_SEIZED; 1024 int ret = -EIO; 1025 kernel_siginfo_t siginfo, *si; 1026 void __user *datavp = (void __user *) data; 1027 unsigned long __user *datalp = datavp; 1028 unsigned long flags; 1029 1030 switch (request) { 1031 case PTRACE_PEEKTEXT: 1032 case PTRACE_PEEKDATA: 1033 return generic_ptrace_peekdata(child, addr, data); 1034 case PTRACE_POKETEXT: 1035 case PTRACE_POKEDATA: 1036 return generic_ptrace_pokedata(child, addr, data); 1037 1038 #ifdef PTRACE_OLDSETOPTIONS 1039 case PTRACE_OLDSETOPTIONS: 1040 #endif 1041 case PTRACE_SETOPTIONS: 1042 ret = ptrace_setoptions(child, data); 1043 break; 1044 case PTRACE_GETEVENTMSG: 1045 ret = put_user(child->ptrace_message, datalp); 1046 break; 1047 1048 case PTRACE_PEEKSIGINFO: 1049 ret = ptrace_peek_siginfo(child, addr, data); 1050 break; 1051 1052 case PTRACE_GETSIGINFO: 1053 ret = ptrace_getsiginfo(child, &siginfo); 1054 if (!ret) 1055 ret = copy_siginfo_to_user(datavp, &siginfo); 1056 break; 1057 1058 case PTRACE_SETSIGINFO: 1059 ret = copy_siginfo_from_user(&siginfo, datavp); 1060 if (!ret) 1061 ret = ptrace_setsiginfo(child, &siginfo); 1062 break; 1063 1064 case PTRACE_GETSIGMASK: { 1065 sigset_t *mask; 1066 1067 if (addr != sizeof(sigset_t)) { 1068 ret = -EINVAL; 1069 break; 1070 } 1071 1072 if (test_tsk_restore_sigmask(child)) 1073 mask = &child->saved_sigmask; 1074 else 1075 mask = &child->blocked; 1076 1077 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1078 ret = -EFAULT; 1079 else 1080 ret = 0; 1081 1082 break; 1083 } 1084 1085 case PTRACE_SETSIGMASK: { 1086 sigset_t new_set; 1087 1088 if (addr != sizeof(sigset_t)) { 1089 ret = -EINVAL; 1090 break; 1091 } 1092 1093 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1094 ret = -EFAULT; 1095 break; 1096 } 1097 1098 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1099 1100 /* 1101 * Every thread does recalc_sigpending() after resume, so 1102 * retarget_shared_pending() and recalc_sigpending() are not 1103 * called here. 1104 */ 1105 spin_lock_irq(&child->sighand->siglock); 1106 child->blocked = new_set; 1107 spin_unlock_irq(&child->sighand->siglock); 1108 1109 clear_tsk_restore_sigmask(child); 1110 1111 ret = 0; 1112 break; 1113 } 1114 1115 case PTRACE_INTERRUPT: 1116 /* 1117 * Stop tracee without any side-effect on signal or job 1118 * control. At least one trap is guaranteed to happen 1119 * after this request. If @child is already trapped, the 1120 * current trap is not disturbed and another trap will 1121 * happen after the current trap is ended with PTRACE_CONT. 1122 * 1123 * The actual trap might not be PTRACE_EVENT_STOP trap but 1124 * the pending condition is cleared regardless. 1125 */ 1126 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1127 break; 1128 1129 /* 1130 * INTERRUPT doesn't disturb existing trap sans one 1131 * exception. If ptracer issued LISTEN for the current 1132 * STOP, this INTERRUPT should clear LISTEN and re-trap 1133 * tracee into STOP. 1134 */ 1135 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1136 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1137 1138 unlock_task_sighand(child, &flags); 1139 ret = 0; 1140 break; 1141 1142 case PTRACE_LISTEN: 1143 /* 1144 * Listen for events. Tracee must be in STOP. It's not 1145 * resumed per-se but is not considered to be in TRACED by 1146 * wait(2) or ptrace(2). If an async event (e.g. group 1147 * stop state change) happens, tracee will enter STOP trap 1148 * again. Alternatively, ptracer can issue INTERRUPT to 1149 * finish listening and re-trap tracee into STOP. 1150 */ 1151 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1152 break; 1153 1154 si = child->last_siginfo; 1155 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1156 child->jobctl |= JOBCTL_LISTENING; 1157 /* 1158 * If NOTIFY is set, it means event happened between 1159 * start of this trap and now. Trigger re-trap. 1160 */ 1161 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1162 ptrace_signal_wake_up(child, true); 1163 ret = 0; 1164 } 1165 unlock_task_sighand(child, &flags); 1166 break; 1167 1168 case PTRACE_DETACH: /* detach a process that was attached. */ 1169 ret = ptrace_detach(child, data); 1170 break; 1171 1172 #ifdef CONFIG_BINFMT_ELF_FDPIC 1173 case PTRACE_GETFDPIC: { 1174 struct mm_struct *mm = get_task_mm(child); 1175 unsigned long tmp = 0; 1176 1177 ret = -ESRCH; 1178 if (!mm) 1179 break; 1180 1181 switch (addr) { 1182 case PTRACE_GETFDPIC_EXEC: 1183 tmp = mm->context.exec_fdpic_loadmap; 1184 break; 1185 case PTRACE_GETFDPIC_INTERP: 1186 tmp = mm->context.interp_fdpic_loadmap; 1187 break; 1188 default: 1189 break; 1190 } 1191 mmput(mm); 1192 1193 ret = put_user(tmp, datalp); 1194 break; 1195 } 1196 #endif 1197 1198 case PTRACE_SINGLESTEP: 1199 #ifdef PTRACE_SINGLEBLOCK 1200 case PTRACE_SINGLEBLOCK: 1201 #endif 1202 #ifdef PTRACE_SYSEMU 1203 case PTRACE_SYSEMU: 1204 case PTRACE_SYSEMU_SINGLESTEP: 1205 #endif 1206 case PTRACE_SYSCALL: 1207 case PTRACE_CONT: 1208 return ptrace_resume(child, request, data); 1209 1210 case PTRACE_KILL: 1211 send_sig_info(SIGKILL, SEND_SIG_NOINFO, child); 1212 return 0; 1213 1214 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1215 case PTRACE_GETREGSET: 1216 case PTRACE_SETREGSET: { 1217 struct iovec kiov; 1218 struct iovec __user *uiov = datavp; 1219 1220 if (!access_ok(uiov, sizeof(*uiov))) 1221 return -EFAULT; 1222 1223 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1224 __get_user(kiov.iov_len, &uiov->iov_len)) 1225 return -EFAULT; 1226 1227 ret = ptrace_regset(child, request, addr, &kiov); 1228 if (!ret) 1229 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1230 break; 1231 } 1232 1233 case PTRACE_GET_SYSCALL_INFO: 1234 ret = ptrace_get_syscall_info(child, addr, datavp); 1235 break; 1236 #endif 1237 1238 case PTRACE_SECCOMP_GET_FILTER: 1239 ret = seccomp_get_filter(child, addr, datavp); 1240 break; 1241 1242 case PTRACE_SECCOMP_GET_METADATA: 1243 ret = seccomp_get_metadata(child, addr, datavp); 1244 break; 1245 1246 #ifdef CONFIG_RSEQ 1247 case PTRACE_GET_RSEQ_CONFIGURATION: 1248 ret = ptrace_get_rseq_configuration(child, addr, datavp); 1249 break; 1250 #endif 1251 1252 case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG: 1253 ret = syscall_user_dispatch_set_config(child, addr, datavp); 1254 break; 1255 1256 case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG: 1257 ret = syscall_user_dispatch_get_config(child, addr, datavp); 1258 break; 1259 1260 default: 1261 break; 1262 } 1263 1264 return ret; 1265 } 1266 1267 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1268 unsigned long, data) 1269 { 1270 struct task_struct *child; 1271 long ret; 1272 1273 if (request == PTRACE_TRACEME) { 1274 ret = ptrace_traceme(); 1275 goto out; 1276 } 1277 1278 child = find_get_task_by_vpid(pid); 1279 if (!child) { 1280 ret = -ESRCH; 1281 goto out; 1282 } 1283 1284 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1285 ret = ptrace_attach(child, request, addr, data); 1286 goto out_put_task_struct; 1287 } 1288 1289 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1290 request == PTRACE_INTERRUPT); 1291 if (ret < 0) 1292 goto out_put_task_struct; 1293 1294 ret = arch_ptrace(child, request, addr, data); 1295 if (ret || request != PTRACE_DETACH) 1296 ptrace_unfreeze_traced(child); 1297 1298 out_put_task_struct: 1299 put_task_struct(child); 1300 out: 1301 return ret; 1302 } 1303 1304 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1305 unsigned long data) 1306 { 1307 unsigned long tmp; 1308 int copied; 1309 1310 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1311 if (copied != sizeof(tmp)) 1312 return -EIO; 1313 return put_user(tmp, (unsigned long __user *)data); 1314 } 1315 1316 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1317 unsigned long data) 1318 { 1319 int copied; 1320 1321 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1322 FOLL_FORCE | FOLL_WRITE); 1323 return (copied == sizeof(data)) ? 0 : -EIO; 1324 } 1325 1326 #if defined CONFIG_COMPAT 1327 1328 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1329 compat_ulong_t addr, compat_ulong_t data) 1330 { 1331 compat_ulong_t __user *datap = compat_ptr(data); 1332 compat_ulong_t word; 1333 kernel_siginfo_t siginfo; 1334 int ret; 1335 1336 switch (request) { 1337 case PTRACE_PEEKTEXT: 1338 case PTRACE_PEEKDATA: 1339 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1340 FOLL_FORCE); 1341 if (ret != sizeof(word)) 1342 ret = -EIO; 1343 else 1344 ret = put_user(word, datap); 1345 break; 1346 1347 case PTRACE_POKETEXT: 1348 case PTRACE_POKEDATA: 1349 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1350 FOLL_FORCE | FOLL_WRITE); 1351 ret = (ret != sizeof(data) ? -EIO : 0); 1352 break; 1353 1354 case PTRACE_GETEVENTMSG: 1355 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1356 break; 1357 1358 case PTRACE_GETSIGINFO: 1359 ret = ptrace_getsiginfo(child, &siginfo); 1360 if (!ret) 1361 ret = copy_siginfo_to_user32( 1362 (struct compat_siginfo __user *) datap, 1363 &siginfo); 1364 break; 1365 1366 case PTRACE_SETSIGINFO: 1367 ret = copy_siginfo_from_user32( 1368 &siginfo, (struct compat_siginfo __user *) datap); 1369 if (!ret) 1370 ret = ptrace_setsiginfo(child, &siginfo); 1371 break; 1372 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1373 case PTRACE_GETREGSET: 1374 case PTRACE_SETREGSET: 1375 { 1376 struct iovec kiov; 1377 struct compat_iovec __user *uiov = 1378 (struct compat_iovec __user *) datap; 1379 compat_uptr_t ptr; 1380 compat_size_t len; 1381 1382 if (!access_ok(uiov, sizeof(*uiov))) 1383 return -EFAULT; 1384 1385 if (__get_user(ptr, &uiov->iov_base) || 1386 __get_user(len, &uiov->iov_len)) 1387 return -EFAULT; 1388 1389 kiov.iov_base = compat_ptr(ptr); 1390 kiov.iov_len = len; 1391 1392 ret = ptrace_regset(child, request, addr, &kiov); 1393 if (!ret) 1394 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1395 break; 1396 } 1397 #endif 1398 1399 default: 1400 ret = ptrace_request(child, request, addr, data); 1401 } 1402 1403 return ret; 1404 } 1405 1406 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1407 compat_long_t, addr, compat_long_t, data) 1408 { 1409 struct task_struct *child; 1410 long ret; 1411 1412 if (request == PTRACE_TRACEME) { 1413 ret = ptrace_traceme(); 1414 goto out; 1415 } 1416 1417 child = find_get_task_by_vpid(pid); 1418 if (!child) { 1419 ret = -ESRCH; 1420 goto out; 1421 } 1422 1423 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1424 ret = ptrace_attach(child, request, addr, data); 1425 goto out_put_task_struct; 1426 } 1427 1428 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1429 request == PTRACE_INTERRUPT); 1430 if (!ret) { 1431 ret = compat_arch_ptrace(child, request, addr, data); 1432 if (ret || request != PTRACE_DETACH) 1433 ptrace_unfreeze_traced(child); 1434 } 1435 1436 out_put_task_struct: 1437 put_task_struct(child); 1438 out: 1439 return ret; 1440 } 1441 #endif /* CONFIG_COMPAT */ 1442