1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/kernel/ptrace.c 4 * 5 * (C) Copyright 1999 Linus Torvalds 6 * 7 * Common interfaces for "ptrace()" which we do not want 8 * to continually duplicate across every architecture. 9 */ 10 11 #include <linux/capability.h> 12 #include <linux/export.h> 13 #include <linux/sched.h> 14 #include <linux/sched/mm.h> 15 #include <linux/sched/coredump.h> 16 #include <linux/sched/task.h> 17 #include <linux/errno.h> 18 #include <linux/mm.h> 19 #include <linux/highmem.h> 20 #include <linux/pagemap.h> 21 #include <linux/ptrace.h> 22 #include <linux/security.h> 23 #include <linux/signal.h> 24 #include <linux/uio.h> 25 #include <linux/audit.h> 26 #include <linux/pid_namespace.h> 27 #include <linux/syscalls.h> 28 #include <linux/uaccess.h> 29 #include <linux/regset.h> 30 #include <linux/hw_breakpoint.h> 31 #include <linux/cn_proc.h> 32 #include <linux/compat.h> 33 #include <linux/sched/signal.h> 34 #include <linux/minmax.h> 35 36 #include <asm/syscall.h> /* for syscall_get_* */ 37 38 /* 39 * Access another process' address space via ptrace. 40 * Source/target buffer must be kernel space, 41 * Do not walk the page table directly, use get_user_pages 42 */ 43 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr, 44 void *buf, int len, unsigned int gup_flags) 45 { 46 struct mm_struct *mm; 47 int ret; 48 49 mm = get_task_mm(tsk); 50 if (!mm) 51 return 0; 52 53 if (!tsk->ptrace || 54 (current != tsk->parent) || 55 ((get_dumpable(mm) != SUID_DUMP_USER) && 56 !ptracer_capable(tsk, mm->user_ns))) { 57 mmput(mm); 58 return 0; 59 } 60 61 ret = __access_remote_vm(mm, addr, buf, len, gup_flags); 62 mmput(mm); 63 64 return ret; 65 } 66 67 68 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent, 69 const struct cred *ptracer_cred) 70 { 71 BUG_ON(!list_empty(&child->ptrace_entry)); 72 list_add(&child->ptrace_entry, &new_parent->ptraced); 73 child->parent = new_parent; 74 child->ptracer_cred = get_cred(ptracer_cred); 75 } 76 77 /* 78 * ptrace a task: make the debugger its new parent and 79 * move it to the ptrace list. 80 * 81 * Must be called with the tasklist lock write-held. 82 */ 83 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent) 84 { 85 __ptrace_link(child, new_parent, current_cred()); 86 } 87 88 /** 89 * __ptrace_unlink - unlink ptracee and restore its execution state 90 * @child: ptracee to be unlinked 91 * 92 * Remove @child from the ptrace list, move it back to the original parent, 93 * and restore the execution state so that it conforms to the group stop 94 * state. 95 * 96 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer 97 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between 98 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. 99 * If the ptracer is exiting, the ptracee can be in any state. 100 * 101 * After detach, the ptracee should be in a state which conforms to the 102 * group stop. If the group is stopped or in the process of stopping, the 103 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken 104 * up from TASK_TRACED. 105 * 106 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, 107 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar 108 * to but in the opposite direction of what happens while attaching to a 109 * stopped task. However, in this direction, the intermediate RUNNING 110 * state is not hidden even from the current ptracer and if it immediately 111 * re-attaches and performs a WNOHANG wait(2), it may fail. 112 * 113 * CONTEXT: 114 * write_lock_irq(tasklist_lock) 115 */ 116 void __ptrace_unlink(struct task_struct *child) 117 { 118 const struct cred *old_cred; 119 BUG_ON(!child->ptrace); 120 121 clear_task_syscall_work(child, SYSCALL_TRACE); 122 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 123 clear_task_syscall_work(child, SYSCALL_EMU); 124 #endif 125 126 child->parent = child->real_parent; 127 list_del_init(&child->ptrace_entry); 128 old_cred = child->ptracer_cred; 129 child->ptracer_cred = NULL; 130 put_cred(old_cred); 131 132 spin_lock(&child->sighand->siglock); 133 child->ptrace = 0; 134 /* 135 * Clear all pending traps and TRAPPING. TRAPPING should be 136 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. 137 */ 138 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); 139 task_clear_jobctl_trapping(child); 140 141 /* 142 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and 143 * @child isn't dead. 144 */ 145 if (!(child->flags & PF_EXITING) && 146 (child->signal->flags & SIGNAL_STOP_STOPPED || 147 child->signal->group_stop_count)) { 148 child->jobctl |= JOBCTL_STOP_PENDING; 149 150 /* 151 * This is only possible if this thread was cloned by the 152 * traced task running in the stopped group, set the signal 153 * for the future reports. 154 * FIXME: we should change ptrace_init_task() to handle this 155 * case. 156 */ 157 if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) 158 child->jobctl |= SIGSTOP; 159 } 160 161 /* 162 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick 163 * @child in the butt. Note that @resume should be used iff @child 164 * is in TASK_TRACED; otherwise, we might unduly disrupt 165 * TASK_KILLABLE sleeps. 166 */ 167 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) 168 ptrace_signal_wake_up(child, true); 169 170 spin_unlock(&child->sighand->siglock); 171 } 172 173 static bool looks_like_a_spurious_pid(struct task_struct *task) 174 { 175 if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP)) 176 return false; 177 178 if (task_pid_vnr(task) == task->ptrace_message) 179 return false; 180 /* 181 * The tracee changed its pid but the PTRACE_EVENT_EXEC event 182 * was not wait()'ed, most probably debugger targets the old 183 * leader which was destroyed in de_thread(). 184 */ 185 return true; 186 } 187 188 /* Ensure that nothing can wake it up, even SIGKILL */ 189 static bool ptrace_freeze_traced(struct task_struct *task) 190 { 191 bool ret = false; 192 193 /* Lockless, nobody but us can set this flag */ 194 if (task->jobctl & JOBCTL_LISTENING) 195 return ret; 196 197 spin_lock_irq(&task->sighand->siglock); 198 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) && 199 !__fatal_signal_pending(task)) { 200 WRITE_ONCE(task->__state, __TASK_TRACED); 201 ret = true; 202 } 203 spin_unlock_irq(&task->sighand->siglock); 204 205 return ret; 206 } 207 208 static void ptrace_unfreeze_traced(struct task_struct *task) 209 { 210 if (READ_ONCE(task->__state) != __TASK_TRACED) 211 return; 212 213 WARN_ON(!task->ptrace || task->parent != current); 214 215 /* 216 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely. 217 * Recheck state under the lock to close this race. 218 */ 219 spin_lock_irq(&task->sighand->siglock); 220 if (READ_ONCE(task->__state) == __TASK_TRACED) { 221 if (__fatal_signal_pending(task)) 222 wake_up_state(task, __TASK_TRACED); 223 else 224 WRITE_ONCE(task->__state, TASK_TRACED); 225 } 226 spin_unlock_irq(&task->sighand->siglock); 227 } 228 229 /** 230 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 231 * @child: ptracee to check for 232 * @ignore_state: don't check whether @child is currently %TASK_TRACED 233 * 234 * Check whether @child is being ptraced by %current and ready for further 235 * ptrace operations. If @ignore_state is %false, @child also should be in 236 * %TASK_TRACED state and on return the child is guaranteed to be traced 237 * and not executing. If @ignore_state is %true, @child can be in any 238 * state. 239 * 240 * CONTEXT: 241 * Grabs and releases tasklist_lock and @child->sighand->siglock. 242 * 243 * RETURNS: 244 * 0 on success, -ESRCH if %child is not ready. 245 */ 246 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 247 { 248 int ret = -ESRCH; 249 250 /* 251 * We take the read lock around doing both checks to close a 252 * possible race where someone else was tracing our child and 253 * detached between these two checks. After this locked check, 254 * we are sure that this is our traced child and that can only 255 * be changed by us so it's not changing right after this. 256 */ 257 read_lock(&tasklist_lock); 258 if (child->ptrace && child->parent == current) { 259 WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED); 260 /* 261 * child->sighand can't be NULL, release_task() 262 * does ptrace_unlink() before __exit_signal(). 263 */ 264 if (ignore_state || ptrace_freeze_traced(child)) 265 ret = 0; 266 } 267 read_unlock(&tasklist_lock); 268 269 if (!ret && !ignore_state) { 270 if (!wait_task_inactive(child, __TASK_TRACED)) { 271 /* 272 * This can only happen if may_ptrace_stop() fails and 273 * ptrace_stop() changes ->state back to TASK_RUNNING, 274 * so we should not worry about leaking __TASK_TRACED. 275 */ 276 WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED); 277 ret = -ESRCH; 278 } 279 } 280 281 return ret; 282 } 283 284 static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 285 { 286 if (mode & PTRACE_MODE_NOAUDIT) 287 return ns_capable_noaudit(ns, CAP_SYS_PTRACE); 288 return ns_capable(ns, CAP_SYS_PTRACE); 289 } 290 291 /* Returns 0 on success, -errno on denial. */ 292 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 293 { 294 const struct cred *cred = current_cred(), *tcred; 295 struct mm_struct *mm; 296 kuid_t caller_uid; 297 kgid_t caller_gid; 298 299 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) { 300 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n"); 301 return -EPERM; 302 } 303 304 /* May we inspect the given task? 305 * This check is used both for attaching with ptrace 306 * and for allowing access to sensitive information in /proc. 307 * 308 * ptrace_attach denies several cases that /proc allows 309 * because setting up the necessary parent/child relationship 310 * or halting the specified task is impossible. 311 */ 312 313 /* Don't let security modules deny introspection */ 314 if (same_thread_group(task, current)) 315 return 0; 316 rcu_read_lock(); 317 if (mode & PTRACE_MODE_FSCREDS) { 318 caller_uid = cred->fsuid; 319 caller_gid = cred->fsgid; 320 } else { 321 /* 322 * Using the euid would make more sense here, but something 323 * in userland might rely on the old behavior, and this 324 * shouldn't be a security problem since 325 * PTRACE_MODE_REALCREDS implies that the caller explicitly 326 * used a syscall that requests access to another process 327 * (and not a filesystem syscall to procfs). 328 */ 329 caller_uid = cred->uid; 330 caller_gid = cred->gid; 331 } 332 tcred = __task_cred(task); 333 if (uid_eq(caller_uid, tcred->euid) && 334 uid_eq(caller_uid, tcred->suid) && 335 uid_eq(caller_uid, tcred->uid) && 336 gid_eq(caller_gid, tcred->egid) && 337 gid_eq(caller_gid, tcred->sgid) && 338 gid_eq(caller_gid, tcred->gid)) 339 goto ok; 340 if (ptrace_has_cap(tcred->user_ns, mode)) 341 goto ok; 342 rcu_read_unlock(); 343 return -EPERM; 344 ok: 345 rcu_read_unlock(); 346 /* 347 * If a task drops privileges and becomes nondumpable (through a syscall 348 * like setresuid()) while we are trying to access it, we must ensure 349 * that the dumpability is read after the credentials; otherwise, 350 * we may be able to attach to a task that we shouldn't be able to 351 * attach to (as if the task had dropped privileges without becoming 352 * nondumpable). 353 * Pairs with a write barrier in commit_creds(). 354 */ 355 smp_rmb(); 356 mm = task->mm; 357 if (mm && 358 ((get_dumpable(mm) != SUID_DUMP_USER) && 359 !ptrace_has_cap(mm->user_ns, mode))) 360 return -EPERM; 361 362 return security_ptrace_access_check(task, mode); 363 } 364 365 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 366 { 367 int err; 368 task_lock(task); 369 err = __ptrace_may_access(task, mode); 370 task_unlock(task); 371 return !err; 372 } 373 374 static int ptrace_attach(struct task_struct *task, long request, 375 unsigned long addr, 376 unsigned long flags) 377 { 378 bool seize = (request == PTRACE_SEIZE); 379 int retval; 380 381 retval = -EIO; 382 if (seize) { 383 if (addr != 0) 384 goto out; 385 if (flags & ~(unsigned long)PTRACE_O_MASK) 386 goto out; 387 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 388 } else { 389 flags = PT_PTRACED; 390 } 391 392 audit_ptrace(task); 393 394 retval = -EPERM; 395 if (unlikely(task->flags & PF_KTHREAD)) 396 goto out; 397 if (same_thread_group(task, current)) 398 goto out; 399 400 /* 401 * Protect exec's credential calculations against our interference; 402 * SUID, SGID and LSM creds get determined differently 403 * under ptrace. 404 */ 405 retval = -ERESTARTNOINTR; 406 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 407 goto out; 408 409 task_lock(task); 410 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); 411 task_unlock(task); 412 if (retval) 413 goto unlock_creds; 414 415 write_lock_irq(&tasklist_lock); 416 retval = -EPERM; 417 if (unlikely(task->exit_state)) 418 goto unlock_tasklist; 419 if (task->ptrace) 420 goto unlock_tasklist; 421 422 task->ptrace = flags; 423 424 ptrace_link(task, current); 425 426 /* SEIZE doesn't trap tracee on attach */ 427 if (!seize) 428 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 429 430 spin_lock(&task->sighand->siglock); 431 432 /* 433 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 434 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 435 * will be cleared if the child completes the transition or any 436 * event which clears the group stop states happens. We'll wait 437 * for the transition to complete before returning from this 438 * function. 439 * 440 * This hides STOPPED -> RUNNING -> TRACED transition from the 441 * attaching thread but a different thread in the same group can 442 * still observe the transient RUNNING state. IOW, if another 443 * thread's WNOHANG wait(2) on the stopped tracee races against 444 * ATTACH, the wait(2) may fail due to the transient RUNNING. 445 * 446 * The following task_is_stopped() test is safe as both transitions 447 * in and out of STOPPED are protected by siglock. 448 */ 449 if (task_is_stopped(task) && 450 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 451 signal_wake_up_state(task, __TASK_STOPPED); 452 453 spin_unlock(&task->sighand->siglock); 454 455 retval = 0; 456 unlock_tasklist: 457 write_unlock_irq(&tasklist_lock); 458 unlock_creds: 459 mutex_unlock(&task->signal->cred_guard_mutex); 460 out: 461 if (!retval) { 462 /* 463 * We do not bother to change retval or clear JOBCTL_TRAPPING 464 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 465 * not return to user-mode, it will exit and clear this bit in 466 * __ptrace_unlink() if it wasn't already cleared by the tracee; 467 * and until then nobody can ptrace this task. 468 */ 469 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 470 proc_ptrace_connector(task, PTRACE_ATTACH); 471 } 472 473 return retval; 474 } 475 476 /** 477 * ptrace_traceme -- helper for PTRACE_TRACEME 478 * 479 * Performs checks and sets PT_PTRACED. 480 * Should be used by all ptrace implementations for PTRACE_TRACEME. 481 */ 482 static int ptrace_traceme(void) 483 { 484 int ret = -EPERM; 485 486 write_lock_irq(&tasklist_lock); 487 /* Are we already being traced? */ 488 if (!current->ptrace) { 489 ret = security_ptrace_traceme(current->parent); 490 /* 491 * Check PF_EXITING to ensure ->real_parent has not passed 492 * exit_ptrace(). Otherwise we don't report the error but 493 * pretend ->real_parent untraces us right after return. 494 */ 495 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 496 current->ptrace = PT_PTRACED; 497 ptrace_link(current, current->real_parent); 498 } 499 } 500 write_unlock_irq(&tasklist_lock); 501 502 return ret; 503 } 504 505 /* 506 * Called with irqs disabled, returns true if childs should reap themselves. 507 */ 508 static int ignoring_children(struct sighand_struct *sigh) 509 { 510 int ret; 511 spin_lock(&sigh->siglock); 512 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 513 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 514 spin_unlock(&sigh->siglock); 515 return ret; 516 } 517 518 /* 519 * Called with tasklist_lock held for writing. 520 * Unlink a traced task, and clean it up if it was a traced zombie. 521 * Return true if it needs to be reaped with release_task(). 522 * (We can't call release_task() here because we already hold tasklist_lock.) 523 * 524 * If it's a zombie, our attachedness prevented normal parent notification 525 * or self-reaping. Do notification now if it would have happened earlier. 526 * If it should reap itself, return true. 527 * 528 * If it's our own child, there is no notification to do. But if our normal 529 * children self-reap, then this child was prevented by ptrace and we must 530 * reap it now, in that case we must also wake up sub-threads sleeping in 531 * do_wait(). 532 */ 533 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 534 { 535 bool dead; 536 537 __ptrace_unlink(p); 538 539 if (p->exit_state != EXIT_ZOMBIE) 540 return false; 541 542 dead = !thread_group_leader(p); 543 544 if (!dead && thread_group_empty(p)) { 545 if (!same_thread_group(p->real_parent, tracer)) 546 dead = do_notify_parent(p, p->exit_signal); 547 else if (ignoring_children(tracer->sighand)) { 548 __wake_up_parent(p, tracer); 549 dead = true; 550 } 551 } 552 /* Mark it as in the process of being reaped. */ 553 if (dead) 554 p->exit_state = EXIT_DEAD; 555 return dead; 556 } 557 558 static int ptrace_detach(struct task_struct *child, unsigned int data) 559 { 560 if (!valid_signal(data)) 561 return -EIO; 562 563 /* Architecture-specific hardware disable .. */ 564 ptrace_disable(child); 565 566 write_lock_irq(&tasklist_lock); 567 /* 568 * We rely on ptrace_freeze_traced(). It can't be killed and 569 * untraced by another thread, it can't be a zombie. 570 */ 571 WARN_ON(!child->ptrace || child->exit_state); 572 /* 573 * tasklist_lock avoids the race with wait_task_stopped(), see 574 * the comment in ptrace_resume(). 575 */ 576 child->exit_code = data; 577 __ptrace_detach(current, child); 578 write_unlock_irq(&tasklist_lock); 579 580 proc_ptrace_connector(child, PTRACE_DETACH); 581 582 return 0; 583 } 584 585 /* 586 * Detach all tasks we were using ptrace on. Called with tasklist held 587 * for writing. 588 */ 589 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 590 { 591 struct task_struct *p, *n; 592 593 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 594 if (unlikely(p->ptrace & PT_EXITKILL)) 595 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 596 597 if (__ptrace_detach(tracer, p)) 598 list_add(&p->ptrace_entry, dead); 599 } 600 } 601 602 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 603 { 604 int copied = 0; 605 606 while (len > 0) { 607 char buf[128]; 608 int this_len, retval; 609 610 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 611 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 612 613 if (!retval) { 614 if (copied) 615 break; 616 return -EIO; 617 } 618 if (copy_to_user(dst, buf, retval)) 619 return -EFAULT; 620 copied += retval; 621 src += retval; 622 dst += retval; 623 len -= retval; 624 } 625 return copied; 626 } 627 628 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 629 { 630 int copied = 0; 631 632 while (len > 0) { 633 char buf[128]; 634 int this_len, retval; 635 636 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 637 if (copy_from_user(buf, src, this_len)) 638 return -EFAULT; 639 retval = ptrace_access_vm(tsk, dst, buf, this_len, 640 FOLL_FORCE | FOLL_WRITE); 641 if (!retval) { 642 if (copied) 643 break; 644 return -EIO; 645 } 646 copied += retval; 647 src += retval; 648 dst += retval; 649 len -= retval; 650 } 651 return copied; 652 } 653 654 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 655 { 656 unsigned flags; 657 658 if (data & ~(unsigned long)PTRACE_O_MASK) 659 return -EINVAL; 660 661 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 662 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 663 !IS_ENABLED(CONFIG_SECCOMP)) 664 return -EINVAL; 665 666 if (!capable(CAP_SYS_ADMIN)) 667 return -EPERM; 668 669 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 670 current->ptrace & PT_SUSPEND_SECCOMP) 671 return -EPERM; 672 } 673 674 /* Avoid intermediate state when all opts are cleared */ 675 flags = child->ptrace; 676 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 677 flags |= (data << PT_OPT_FLAG_SHIFT); 678 child->ptrace = flags; 679 680 return 0; 681 } 682 683 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 684 { 685 unsigned long flags; 686 int error = -ESRCH; 687 688 if (lock_task_sighand(child, &flags)) { 689 error = -EINVAL; 690 if (likely(child->last_siginfo != NULL)) { 691 copy_siginfo(info, child->last_siginfo); 692 error = 0; 693 } 694 unlock_task_sighand(child, &flags); 695 } 696 return error; 697 } 698 699 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 700 { 701 unsigned long flags; 702 int error = -ESRCH; 703 704 if (lock_task_sighand(child, &flags)) { 705 error = -EINVAL; 706 if (likely(child->last_siginfo != NULL)) { 707 copy_siginfo(child->last_siginfo, info); 708 error = 0; 709 } 710 unlock_task_sighand(child, &flags); 711 } 712 return error; 713 } 714 715 static int ptrace_peek_siginfo(struct task_struct *child, 716 unsigned long addr, 717 unsigned long data) 718 { 719 struct ptrace_peeksiginfo_args arg; 720 struct sigpending *pending; 721 struct sigqueue *q; 722 int ret, i; 723 724 ret = copy_from_user(&arg, (void __user *) addr, 725 sizeof(struct ptrace_peeksiginfo_args)); 726 if (ret) 727 return -EFAULT; 728 729 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 730 return -EINVAL; /* unknown flags */ 731 732 if (arg.nr < 0) 733 return -EINVAL; 734 735 /* Ensure arg.off fits in an unsigned long */ 736 if (arg.off > ULONG_MAX) 737 return 0; 738 739 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 740 pending = &child->signal->shared_pending; 741 else 742 pending = &child->pending; 743 744 for (i = 0; i < arg.nr; ) { 745 kernel_siginfo_t info; 746 unsigned long off = arg.off + i; 747 bool found = false; 748 749 spin_lock_irq(&child->sighand->siglock); 750 list_for_each_entry(q, &pending->list, list) { 751 if (!off--) { 752 found = true; 753 copy_siginfo(&info, &q->info); 754 break; 755 } 756 } 757 spin_unlock_irq(&child->sighand->siglock); 758 759 if (!found) /* beyond the end of the list */ 760 break; 761 762 #ifdef CONFIG_COMPAT 763 if (unlikely(in_compat_syscall())) { 764 compat_siginfo_t __user *uinfo = compat_ptr(data); 765 766 if (copy_siginfo_to_user32(uinfo, &info)) { 767 ret = -EFAULT; 768 break; 769 } 770 771 } else 772 #endif 773 { 774 siginfo_t __user *uinfo = (siginfo_t __user *) data; 775 776 if (copy_siginfo_to_user(uinfo, &info)) { 777 ret = -EFAULT; 778 break; 779 } 780 } 781 782 data += sizeof(siginfo_t); 783 i++; 784 785 if (signal_pending(current)) 786 break; 787 788 cond_resched(); 789 } 790 791 if (i > 0) 792 return i; 793 794 return ret; 795 } 796 797 #ifdef CONFIG_RSEQ 798 static long ptrace_get_rseq_configuration(struct task_struct *task, 799 unsigned long size, void __user *data) 800 { 801 struct ptrace_rseq_configuration conf = { 802 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, 803 .rseq_abi_size = sizeof(*task->rseq), 804 .signature = task->rseq_sig, 805 .flags = 0, 806 }; 807 808 size = min_t(unsigned long, size, sizeof(conf)); 809 if (copy_to_user(data, &conf, size)) 810 return -EFAULT; 811 return sizeof(conf); 812 } 813 #endif 814 815 #ifdef PTRACE_SINGLESTEP 816 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 817 #else 818 #define is_singlestep(request) 0 819 #endif 820 821 #ifdef PTRACE_SINGLEBLOCK 822 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 823 #else 824 #define is_singleblock(request) 0 825 #endif 826 827 #ifdef PTRACE_SYSEMU 828 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 829 #else 830 #define is_sysemu_singlestep(request) 0 831 #endif 832 833 static int ptrace_resume(struct task_struct *child, long request, 834 unsigned long data) 835 { 836 bool need_siglock; 837 838 if (!valid_signal(data)) 839 return -EIO; 840 841 if (request == PTRACE_SYSCALL) 842 set_task_syscall_work(child, SYSCALL_TRACE); 843 else 844 clear_task_syscall_work(child, SYSCALL_TRACE); 845 846 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 847 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 848 set_task_syscall_work(child, SYSCALL_EMU); 849 else 850 clear_task_syscall_work(child, SYSCALL_EMU); 851 #endif 852 853 if (is_singleblock(request)) { 854 if (unlikely(!arch_has_block_step())) 855 return -EIO; 856 user_enable_block_step(child); 857 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 858 if (unlikely(!arch_has_single_step())) 859 return -EIO; 860 user_enable_single_step(child); 861 } else { 862 user_disable_single_step(child); 863 } 864 865 /* 866 * Change ->exit_code and ->state under siglock to avoid the race 867 * with wait_task_stopped() in between; a non-zero ->exit_code will 868 * wrongly look like another report from tracee. 869 * 870 * Note that we need siglock even if ->exit_code == data and/or this 871 * status was not reported yet, the new status must not be cleared by 872 * wait_task_stopped() after resume. 873 * 874 * If data == 0 we do not care if wait_task_stopped() reports the old 875 * status and clears the code too; this can't race with the tracee, it 876 * takes siglock after resume. 877 */ 878 need_siglock = data && !thread_group_empty(current); 879 if (need_siglock) 880 spin_lock_irq(&child->sighand->siglock); 881 child->exit_code = data; 882 wake_up_state(child, __TASK_TRACED); 883 if (need_siglock) 884 spin_unlock_irq(&child->sighand->siglock); 885 886 return 0; 887 } 888 889 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 890 891 static const struct user_regset * 892 find_regset(const struct user_regset_view *view, unsigned int type) 893 { 894 const struct user_regset *regset; 895 int n; 896 897 for (n = 0; n < view->n; ++n) { 898 regset = view->regsets + n; 899 if (regset->core_note_type == type) 900 return regset; 901 } 902 903 return NULL; 904 } 905 906 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 907 struct iovec *kiov) 908 { 909 const struct user_regset_view *view = task_user_regset_view(task); 910 const struct user_regset *regset = find_regset(view, type); 911 int regset_no; 912 913 if (!regset || (kiov->iov_len % regset->size) != 0) 914 return -EINVAL; 915 916 regset_no = regset - view->regsets; 917 kiov->iov_len = min(kiov->iov_len, 918 (__kernel_size_t) (regset->n * regset->size)); 919 920 if (req == PTRACE_GETREGSET) 921 return copy_regset_to_user(task, view, regset_no, 0, 922 kiov->iov_len, kiov->iov_base); 923 else 924 return copy_regset_from_user(task, view, regset_no, 0, 925 kiov->iov_len, kiov->iov_base); 926 } 927 928 /* 929 * This is declared in linux/regset.h and defined in machine-dependent 930 * code. We put the export here, near the primary machine-neutral use, 931 * to ensure no machine forgets it. 932 */ 933 EXPORT_SYMBOL_GPL(task_user_regset_view); 934 935 static unsigned long 936 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 937 struct ptrace_syscall_info *info) 938 { 939 unsigned long args[ARRAY_SIZE(info->entry.args)]; 940 int i; 941 942 info->op = PTRACE_SYSCALL_INFO_ENTRY; 943 info->entry.nr = syscall_get_nr(child, regs); 944 syscall_get_arguments(child, regs, args); 945 for (i = 0; i < ARRAY_SIZE(args); i++) 946 info->entry.args[i] = args[i]; 947 948 /* args is the last field in struct ptrace_syscall_info.entry */ 949 return offsetofend(struct ptrace_syscall_info, entry.args); 950 } 951 952 static unsigned long 953 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 954 struct ptrace_syscall_info *info) 955 { 956 /* 957 * As struct ptrace_syscall_info.entry is currently a subset 958 * of struct ptrace_syscall_info.seccomp, it makes sense to 959 * initialize that subset using ptrace_get_syscall_info_entry(). 960 * This can be reconsidered in the future if these structures 961 * diverge significantly enough. 962 */ 963 ptrace_get_syscall_info_entry(child, regs, info); 964 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 965 info->seccomp.ret_data = child->ptrace_message; 966 967 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 968 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 969 } 970 971 static unsigned long 972 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 973 struct ptrace_syscall_info *info) 974 { 975 info->op = PTRACE_SYSCALL_INFO_EXIT; 976 info->exit.rval = syscall_get_error(child, regs); 977 info->exit.is_error = !!info->exit.rval; 978 if (!info->exit.is_error) 979 info->exit.rval = syscall_get_return_value(child, regs); 980 981 /* is_error is the last field in struct ptrace_syscall_info.exit */ 982 return offsetofend(struct ptrace_syscall_info, exit.is_error); 983 } 984 985 static int 986 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 987 void __user *datavp) 988 { 989 struct pt_regs *regs = task_pt_regs(child); 990 struct ptrace_syscall_info info = { 991 .op = PTRACE_SYSCALL_INFO_NONE, 992 .arch = syscall_get_arch(child), 993 .instruction_pointer = instruction_pointer(regs), 994 .stack_pointer = user_stack_pointer(regs), 995 }; 996 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 997 unsigned long write_size; 998 999 /* 1000 * This does not need lock_task_sighand() to access 1001 * child->last_siginfo because ptrace_freeze_traced() 1002 * called earlier by ptrace_check_attach() ensures that 1003 * the tracee cannot go away and clear its last_siginfo. 1004 */ 1005 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 1006 case SIGTRAP | 0x80: 1007 switch (child->ptrace_message) { 1008 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 1009 actual_size = ptrace_get_syscall_info_entry(child, regs, 1010 &info); 1011 break; 1012 case PTRACE_EVENTMSG_SYSCALL_EXIT: 1013 actual_size = ptrace_get_syscall_info_exit(child, regs, 1014 &info); 1015 break; 1016 } 1017 break; 1018 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 1019 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 1020 &info); 1021 break; 1022 } 1023 1024 write_size = min(actual_size, user_size); 1025 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 1026 } 1027 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 1028 1029 int ptrace_request(struct task_struct *child, long request, 1030 unsigned long addr, unsigned long data) 1031 { 1032 bool seized = child->ptrace & PT_SEIZED; 1033 int ret = -EIO; 1034 kernel_siginfo_t siginfo, *si; 1035 void __user *datavp = (void __user *) data; 1036 unsigned long __user *datalp = datavp; 1037 unsigned long flags; 1038 1039 switch (request) { 1040 case PTRACE_PEEKTEXT: 1041 case PTRACE_PEEKDATA: 1042 return generic_ptrace_peekdata(child, addr, data); 1043 case PTRACE_POKETEXT: 1044 case PTRACE_POKEDATA: 1045 return generic_ptrace_pokedata(child, addr, data); 1046 1047 #ifdef PTRACE_OLDSETOPTIONS 1048 case PTRACE_OLDSETOPTIONS: 1049 #endif 1050 case PTRACE_SETOPTIONS: 1051 ret = ptrace_setoptions(child, data); 1052 break; 1053 case PTRACE_GETEVENTMSG: 1054 ret = put_user(child->ptrace_message, datalp); 1055 break; 1056 1057 case PTRACE_PEEKSIGINFO: 1058 ret = ptrace_peek_siginfo(child, addr, data); 1059 break; 1060 1061 case PTRACE_GETSIGINFO: 1062 ret = ptrace_getsiginfo(child, &siginfo); 1063 if (!ret) 1064 ret = copy_siginfo_to_user(datavp, &siginfo); 1065 break; 1066 1067 case PTRACE_SETSIGINFO: 1068 ret = copy_siginfo_from_user(&siginfo, datavp); 1069 if (!ret) 1070 ret = ptrace_setsiginfo(child, &siginfo); 1071 break; 1072 1073 case PTRACE_GETSIGMASK: { 1074 sigset_t *mask; 1075 1076 if (addr != sizeof(sigset_t)) { 1077 ret = -EINVAL; 1078 break; 1079 } 1080 1081 if (test_tsk_restore_sigmask(child)) 1082 mask = &child->saved_sigmask; 1083 else 1084 mask = &child->blocked; 1085 1086 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1087 ret = -EFAULT; 1088 else 1089 ret = 0; 1090 1091 break; 1092 } 1093 1094 case PTRACE_SETSIGMASK: { 1095 sigset_t new_set; 1096 1097 if (addr != sizeof(sigset_t)) { 1098 ret = -EINVAL; 1099 break; 1100 } 1101 1102 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1103 ret = -EFAULT; 1104 break; 1105 } 1106 1107 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1108 1109 /* 1110 * Every thread does recalc_sigpending() after resume, so 1111 * retarget_shared_pending() and recalc_sigpending() are not 1112 * called here. 1113 */ 1114 spin_lock_irq(&child->sighand->siglock); 1115 child->blocked = new_set; 1116 spin_unlock_irq(&child->sighand->siglock); 1117 1118 clear_tsk_restore_sigmask(child); 1119 1120 ret = 0; 1121 break; 1122 } 1123 1124 case PTRACE_INTERRUPT: 1125 /* 1126 * Stop tracee without any side-effect on signal or job 1127 * control. At least one trap is guaranteed to happen 1128 * after this request. If @child is already trapped, the 1129 * current trap is not disturbed and another trap will 1130 * happen after the current trap is ended with PTRACE_CONT. 1131 * 1132 * The actual trap might not be PTRACE_EVENT_STOP trap but 1133 * the pending condition is cleared regardless. 1134 */ 1135 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1136 break; 1137 1138 /* 1139 * INTERRUPT doesn't disturb existing trap sans one 1140 * exception. If ptracer issued LISTEN for the current 1141 * STOP, this INTERRUPT should clear LISTEN and re-trap 1142 * tracee into STOP. 1143 */ 1144 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1145 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1146 1147 unlock_task_sighand(child, &flags); 1148 ret = 0; 1149 break; 1150 1151 case PTRACE_LISTEN: 1152 /* 1153 * Listen for events. Tracee must be in STOP. It's not 1154 * resumed per-se but is not considered to be in TRACED by 1155 * wait(2) or ptrace(2). If an async event (e.g. group 1156 * stop state change) happens, tracee will enter STOP trap 1157 * again. Alternatively, ptracer can issue INTERRUPT to 1158 * finish listening and re-trap tracee into STOP. 1159 */ 1160 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1161 break; 1162 1163 si = child->last_siginfo; 1164 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1165 child->jobctl |= JOBCTL_LISTENING; 1166 /* 1167 * If NOTIFY is set, it means event happened between 1168 * start of this trap and now. Trigger re-trap. 1169 */ 1170 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1171 ptrace_signal_wake_up(child, true); 1172 ret = 0; 1173 } 1174 unlock_task_sighand(child, &flags); 1175 break; 1176 1177 case PTRACE_DETACH: /* detach a process that was attached. */ 1178 ret = ptrace_detach(child, data); 1179 break; 1180 1181 #ifdef CONFIG_BINFMT_ELF_FDPIC 1182 case PTRACE_GETFDPIC: { 1183 struct mm_struct *mm = get_task_mm(child); 1184 unsigned long tmp = 0; 1185 1186 ret = -ESRCH; 1187 if (!mm) 1188 break; 1189 1190 switch (addr) { 1191 case PTRACE_GETFDPIC_EXEC: 1192 tmp = mm->context.exec_fdpic_loadmap; 1193 break; 1194 case PTRACE_GETFDPIC_INTERP: 1195 tmp = mm->context.interp_fdpic_loadmap; 1196 break; 1197 default: 1198 break; 1199 } 1200 mmput(mm); 1201 1202 ret = put_user(tmp, datalp); 1203 break; 1204 } 1205 #endif 1206 1207 #ifdef PTRACE_SINGLESTEP 1208 case PTRACE_SINGLESTEP: 1209 #endif 1210 #ifdef PTRACE_SINGLEBLOCK 1211 case PTRACE_SINGLEBLOCK: 1212 #endif 1213 #ifdef PTRACE_SYSEMU 1214 case PTRACE_SYSEMU: 1215 case PTRACE_SYSEMU_SINGLESTEP: 1216 #endif 1217 case PTRACE_SYSCALL: 1218 case PTRACE_CONT: 1219 return ptrace_resume(child, request, data); 1220 1221 case PTRACE_KILL: 1222 if (child->exit_state) /* already dead */ 1223 return 0; 1224 return ptrace_resume(child, request, SIGKILL); 1225 1226 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1227 case PTRACE_GETREGSET: 1228 case PTRACE_SETREGSET: { 1229 struct iovec kiov; 1230 struct iovec __user *uiov = datavp; 1231 1232 if (!access_ok(uiov, sizeof(*uiov))) 1233 return -EFAULT; 1234 1235 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1236 __get_user(kiov.iov_len, &uiov->iov_len)) 1237 return -EFAULT; 1238 1239 ret = ptrace_regset(child, request, addr, &kiov); 1240 if (!ret) 1241 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1242 break; 1243 } 1244 1245 case PTRACE_GET_SYSCALL_INFO: 1246 ret = ptrace_get_syscall_info(child, addr, datavp); 1247 break; 1248 #endif 1249 1250 case PTRACE_SECCOMP_GET_FILTER: 1251 ret = seccomp_get_filter(child, addr, datavp); 1252 break; 1253 1254 case PTRACE_SECCOMP_GET_METADATA: 1255 ret = seccomp_get_metadata(child, addr, datavp); 1256 break; 1257 1258 #ifdef CONFIG_RSEQ 1259 case PTRACE_GET_RSEQ_CONFIGURATION: 1260 ret = ptrace_get_rseq_configuration(child, addr, datavp); 1261 break; 1262 #endif 1263 1264 default: 1265 break; 1266 } 1267 1268 return ret; 1269 } 1270 1271 #ifndef arch_ptrace_attach 1272 #define arch_ptrace_attach(child) do { } while (0) 1273 #endif 1274 1275 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1276 unsigned long, data) 1277 { 1278 struct task_struct *child; 1279 long ret; 1280 1281 if (request == PTRACE_TRACEME) { 1282 ret = ptrace_traceme(); 1283 if (!ret) 1284 arch_ptrace_attach(current); 1285 goto out; 1286 } 1287 1288 child = find_get_task_by_vpid(pid); 1289 if (!child) { 1290 ret = -ESRCH; 1291 goto out; 1292 } 1293 1294 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1295 ret = ptrace_attach(child, request, addr, data); 1296 /* 1297 * Some architectures need to do book-keeping after 1298 * a ptrace attach. 1299 */ 1300 if (!ret) 1301 arch_ptrace_attach(child); 1302 goto out_put_task_struct; 1303 } 1304 1305 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1306 request == PTRACE_INTERRUPT); 1307 if (ret < 0) 1308 goto out_put_task_struct; 1309 1310 ret = arch_ptrace(child, request, addr, data); 1311 if (ret || request != PTRACE_DETACH) 1312 ptrace_unfreeze_traced(child); 1313 1314 out_put_task_struct: 1315 put_task_struct(child); 1316 out: 1317 return ret; 1318 } 1319 1320 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1321 unsigned long data) 1322 { 1323 unsigned long tmp; 1324 int copied; 1325 1326 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1327 if (copied != sizeof(tmp)) 1328 return -EIO; 1329 return put_user(tmp, (unsigned long __user *)data); 1330 } 1331 1332 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1333 unsigned long data) 1334 { 1335 int copied; 1336 1337 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1338 FOLL_FORCE | FOLL_WRITE); 1339 return (copied == sizeof(data)) ? 0 : -EIO; 1340 } 1341 1342 #if defined CONFIG_COMPAT 1343 1344 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1345 compat_ulong_t addr, compat_ulong_t data) 1346 { 1347 compat_ulong_t __user *datap = compat_ptr(data); 1348 compat_ulong_t word; 1349 kernel_siginfo_t siginfo; 1350 int ret; 1351 1352 switch (request) { 1353 case PTRACE_PEEKTEXT: 1354 case PTRACE_PEEKDATA: 1355 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1356 FOLL_FORCE); 1357 if (ret != sizeof(word)) 1358 ret = -EIO; 1359 else 1360 ret = put_user(word, datap); 1361 break; 1362 1363 case PTRACE_POKETEXT: 1364 case PTRACE_POKEDATA: 1365 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1366 FOLL_FORCE | FOLL_WRITE); 1367 ret = (ret != sizeof(data) ? -EIO : 0); 1368 break; 1369 1370 case PTRACE_GETEVENTMSG: 1371 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1372 break; 1373 1374 case PTRACE_GETSIGINFO: 1375 ret = ptrace_getsiginfo(child, &siginfo); 1376 if (!ret) 1377 ret = copy_siginfo_to_user32( 1378 (struct compat_siginfo __user *) datap, 1379 &siginfo); 1380 break; 1381 1382 case PTRACE_SETSIGINFO: 1383 ret = copy_siginfo_from_user32( 1384 &siginfo, (struct compat_siginfo __user *) datap); 1385 if (!ret) 1386 ret = ptrace_setsiginfo(child, &siginfo); 1387 break; 1388 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1389 case PTRACE_GETREGSET: 1390 case PTRACE_SETREGSET: 1391 { 1392 struct iovec kiov; 1393 struct compat_iovec __user *uiov = 1394 (struct compat_iovec __user *) datap; 1395 compat_uptr_t ptr; 1396 compat_size_t len; 1397 1398 if (!access_ok(uiov, sizeof(*uiov))) 1399 return -EFAULT; 1400 1401 if (__get_user(ptr, &uiov->iov_base) || 1402 __get_user(len, &uiov->iov_len)) 1403 return -EFAULT; 1404 1405 kiov.iov_base = compat_ptr(ptr); 1406 kiov.iov_len = len; 1407 1408 ret = ptrace_regset(child, request, addr, &kiov); 1409 if (!ret) 1410 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1411 break; 1412 } 1413 #endif 1414 1415 default: 1416 ret = ptrace_request(child, request, addr, data); 1417 } 1418 1419 return ret; 1420 } 1421 1422 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1423 compat_long_t, addr, compat_long_t, data) 1424 { 1425 struct task_struct *child; 1426 long ret; 1427 1428 if (request == PTRACE_TRACEME) { 1429 ret = ptrace_traceme(); 1430 goto out; 1431 } 1432 1433 child = find_get_task_by_vpid(pid); 1434 if (!child) { 1435 ret = -ESRCH; 1436 goto out; 1437 } 1438 1439 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1440 ret = ptrace_attach(child, request, addr, data); 1441 /* 1442 * Some architectures need to do book-keeping after 1443 * a ptrace attach. 1444 */ 1445 if (!ret) 1446 arch_ptrace_attach(child); 1447 goto out_put_task_struct; 1448 } 1449 1450 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1451 request == PTRACE_INTERRUPT); 1452 if (!ret) { 1453 ret = compat_arch_ptrace(child, request, addr, data); 1454 if (ret || request != PTRACE_DETACH) 1455 ptrace_unfreeze_traced(child); 1456 } 1457 1458 out_put_task_struct: 1459 put_task_struct(child); 1460 out: 1461 return ret; 1462 } 1463 #endif /* CONFIG_COMPAT */ 1464