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 if (seize) 423 flags |= PT_SEIZED; 424 task->ptrace = flags; 425 426 ptrace_link(task, current); 427 428 /* SEIZE doesn't trap tracee on attach */ 429 if (!seize) 430 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 431 432 spin_lock(&task->sighand->siglock); 433 434 /* 435 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 436 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 437 * will be cleared if the child completes the transition or any 438 * event which clears the group stop states happens. We'll wait 439 * for the transition to complete before returning from this 440 * function. 441 * 442 * This hides STOPPED -> RUNNING -> TRACED transition from the 443 * attaching thread but a different thread in the same group can 444 * still observe the transient RUNNING state. IOW, if another 445 * thread's WNOHANG wait(2) on the stopped tracee races against 446 * ATTACH, the wait(2) may fail due to the transient RUNNING. 447 * 448 * The following task_is_stopped() test is safe as both transitions 449 * in and out of STOPPED are protected by siglock. 450 */ 451 if (task_is_stopped(task) && 452 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 453 signal_wake_up_state(task, __TASK_STOPPED); 454 455 spin_unlock(&task->sighand->siglock); 456 457 retval = 0; 458 unlock_tasklist: 459 write_unlock_irq(&tasklist_lock); 460 unlock_creds: 461 mutex_unlock(&task->signal->cred_guard_mutex); 462 out: 463 if (!retval) { 464 /* 465 * We do not bother to change retval or clear JOBCTL_TRAPPING 466 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 467 * not return to user-mode, it will exit and clear this bit in 468 * __ptrace_unlink() if it wasn't already cleared by the tracee; 469 * and until then nobody can ptrace this task. 470 */ 471 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 472 proc_ptrace_connector(task, PTRACE_ATTACH); 473 } 474 475 return retval; 476 } 477 478 /** 479 * ptrace_traceme -- helper for PTRACE_TRACEME 480 * 481 * Performs checks and sets PT_PTRACED. 482 * Should be used by all ptrace implementations for PTRACE_TRACEME. 483 */ 484 static int ptrace_traceme(void) 485 { 486 int ret = -EPERM; 487 488 write_lock_irq(&tasklist_lock); 489 /* Are we already being traced? */ 490 if (!current->ptrace) { 491 ret = security_ptrace_traceme(current->parent); 492 /* 493 * Check PF_EXITING to ensure ->real_parent has not passed 494 * exit_ptrace(). Otherwise we don't report the error but 495 * pretend ->real_parent untraces us right after return. 496 */ 497 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 498 current->ptrace = PT_PTRACED; 499 ptrace_link(current, current->real_parent); 500 } 501 } 502 write_unlock_irq(&tasklist_lock); 503 504 return ret; 505 } 506 507 /* 508 * Called with irqs disabled, returns true if childs should reap themselves. 509 */ 510 static int ignoring_children(struct sighand_struct *sigh) 511 { 512 int ret; 513 spin_lock(&sigh->siglock); 514 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 515 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 516 spin_unlock(&sigh->siglock); 517 return ret; 518 } 519 520 /* 521 * Called with tasklist_lock held for writing. 522 * Unlink a traced task, and clean it up if it was a traced zombie. 523 * Return true if it needs to be reaped with release_task(). 524 * (We can't call release_task() here because we already hold tasklist_lock.) 525 * 526 * If it's a zombie, our attachedness prevented normal parent notification 527 * or self-reaping. Do notification now if it would have happened earlier. 528 * If it should reap itself, return true. 529 * 530 * If it's our own child, there is no notification to do. But if our normal 531 * children self-reap, then this child was prevented by ptrace and we must 532 * reap it now, in that case we must also wake up sub-threads sleeping in 533 * do_wait(). 534 */ 535 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 536 { 537 bool dead; 538 539 __ptrace_unlink(p); 540 541 if (p->exit_state != EXIT_ZOMBIE) 542 return false; 543 544 dead = !thread_group_leader(p); 545 546 if (!dead && thread_group_empty(p)) { 547 if (!same_thread_group(p->real_parent, tracer)) 548 dead = do_notify_parent(p, p->exit_signal); 549 else if (ignoring_children(tracer->sighand)) { 550 __wake_up_parent(p, tracer); 551 dead = true; 552 } 553 } 554 /* Mark it as in the process of being reaped. */ 555 if (dead) 556 p->exit_state = EXIT_DEAD; 557 return dead; 558 } 559 560 static int ptrace_detach(struct task_struct *child, unsigned int data) 561 { 562 if (!valid_signal(data)) 563 return -EIO; 564 565 /* Architecture-specific hardware disable .. */ 566 ptrace_disable(child); 567 568 write_lock_irq(&tasklist_lock); 569 /* 570 * We rely on ptrace_freeze_traced(). It can't be killed and 571 * untraced by another thread, it can't be a zombie. 572 */ 573 WARN_ON(!child->ptrace || child->exit_state); 574 /* 575 * tasklist_lock avoids the race with wait_task_stopped(), see 576 * the comment in ptrace_resume(). 577 */ 578 child->exit_code = data; 579 __ptrace_detach(current, child); 580 write_unlock_irq(&tasklist_lock); 581 582 proc_ptrace_connector(child, PTRACE_DETACH); 583 584 return 0; 585 } 586 587 /* 588 * Detach all tasks we were using ptrace on. Called with tasklist held 589 * for writing. 590 */ 591 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 592 { 593 struct task_struct *p, *n; 594 595 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 596 if (unlikely(p->ptrace & PT_EXITKILL)) 597 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 598 599 if (__ptrace_detach(tracer, p)) 600 list_add(&p->ptrace_entry, dead); 601 } 602 } 603 604 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 605 { 606 int copied = 0; 607 608 while (len > 0) { 609 char buf[128]; 610 int this_len, retval; 611 612 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 613 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 614 615 if (!retval) { 616 if (copied) 617 break; 618 return -EIO; 619 } 620 if (copy_to_user(dst, buf, retval)) 621 return -EFAULT; 622 copied += retval; 623 src += retval; 624 dst += retval; 625 len -= retval; 626 } 627 return copied; 628 } 629 630 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 631 { 632 int copied = 0; 633 634 while (len > 0) { 635 char buf[128]; 636 int this_len, retval; 637 638 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 639 if (copy_from_user(buf, src, this_len)) 640 return -EFAULT; 641 retval = ptrace_access_vm(tsk, dst, buf, this_len, 642 FOLL_FORCE | FOLL_WRITE); 643 if (!retval) { 644 if (copied) 645 break; 646 return -EIO; 647 } 648 copied += retval; 649 src += retval; 650 dst += retval; 651 len -= retval; 652 } 653 return copied; 654 } 655 656 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 657 { 658 unsigned flags; 659 660 if (data & ~(unsigned long)PTRACE_O_MASK) 661 return -EINVAL; 662 663 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 664 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 665 !IS_ENABLED(CONFIG_SECCOMP)) 666 return -EINVAL; 667 668 if (!capable(CAP_SYS_ADMIN)) 669 return -EPERM; 670 671 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 672 current->ptrace & PT_SUSPEND_SECCOMP) 673 return -EPERM; 674 } 675 676 /* Avoid intermediate state when all opts are cleared */ 677 flags = child->ptrace; 678 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 679 flags |= (data << PT_OPT_FLAG_SHIFT); 680 child->ptrace = flags; 681 682 return 0; 683 } 684 685 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 686 { 687 unsigned long flags; 688 int error = -ESRCH; 689 690 if (lock_task_sighand(child, &flags)) { 691 error = -EINVAL; 692 if (likely(child->last_siginfo != NULL)) { 693 copy_siginfo(info, child->last_siginfo); 694 error = 0; 695 } 696 unlock_task_sighand(child, &flags); 697 } 698 return error; 699 } 700 701 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 702 { 703 unsigned long flags; 704 int error = -ESRCH; 705 706 if (lock_task_sighand(child, &flags)) { 707 error = -EINVAL; 708 if (likely(child->last_siginfo != NULL)) { 709 copy_siginfo(child->last_siginfo, info); 710 error = 0; 711 } 712 unlock_task_sighand(child, &flags); 713 } 714 return error; 715 } 716 717 static int ptrace_peek_siginfo(struct task_struct *child, 718 unsigned long addr, 719 unsigned long data) 720 { 721 struct ptrace_peeksiginfo_args arg; 722 struct sigpending *pending; 723 struct sigqueue *q; 724 int ret, i; 725 726 ret = copy_from_user(&arg, (void __user *) addr, 727 sizeof(struct ptrace_peeksiginfo_args)); 728 if (ret) 729 return -EFAULT; 730 731 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 732 return -EINVAL; /* unknown flags */ 733 734 if (arg.nr < 0) 735 return -EINVAL; 736 737 /* Ensure arg.off fits in an unsigned long */ 738 if (arg.off > ULONG_MAX) 739 return 0; 740 741 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 742 pending = &child->signal->shared_pending; 743 else 744 pending = &child->pending; 745 746 for (i = 0; i < arg.nr; ) { 747 kernel_siginfo_t info; 748 unsigned long off = arg.off + i; 749 bool found = false; 750 751 spin_lock_irq(&child->sighand->siglock); 752 list_for_each_entry(q, &pending->list, list) { 753 if (!off--) { 754 found = true; 755 copy_siginfo(&info, &q->info); 756 break; 757 } 758 } 759 spin_unlock_irq(&child->sighand->siglock); 760 761 if (!found) /* beyond the end of the list */ 762 break; 763 764 #ifdef CONFIG_COMPAT 765 if (unlikely(in_compat_syscall())) { 766 compat_siginfo_t __user *uinfo = compat_ptr(data); 767 768 if (copy_siginfo_to_user32(uinfo, &info)) { 769 ret = -EFAULT; 770 break; 771 } 772 773 } else 774 #endif 775 { 776 siginfo_t __user *uinfo = (siginfo_t __user *) data; 777 778 if (copy_siginfo_to_user(uinfo, &info)) { 779 ret = -EFAULT; 780 break; 781 } 782 } 783 784 data += sizeof(siginfo_t); 785 i++; 786 787 if (signal_pending(current)) 788 break; 789 790 cond_resched(); 791 } 792 793 if (i > 0) 794 return i; 795 796 return ret; 797 } 798 799 #ifdef CONFIG_RSEQ 800 static long ptrace_get_rseq_configuration(struct task_struct *task, 801 unsigned long size, void __user *data) 802 { 803 struct ptrace_rseq_configuration conf = { 804 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, 805 .rseq_abi_size = sizeof(*task->rseq), 806 .signature = task->rseq_sig, 807 .flags = 0, 808 }; 809 810 size = min_t(unsigned long, size, sizeof(conf)); 811 if (copy_to_user(data, &conf, size)) 812 return -EFAULT; 813 return sizeof(conf); 814 } 815 #endif 816 817 #ifdef PTRACE_SINGLESTEP 818 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 819 #else 820 #define is_singlestep(request) 0 821 #endif 822 823 #ifdef PTRACE_SINGLEBLOCK 824 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 825 #else 826 #define is_singleblock(request) 0 827 #endif 828 829 #ifdef PTRACE_SYSEMU 830 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 831 #else 832 #define is_sysemu_singlestep(request) 0 833 #endif 834 835 static int ptrace_resume(struct task_struct *child, long request, 836 unsigned long data) 837 { 838 bool need_siglock; 839 840 if (!valid_signal(data)) 841 return -EIO; 842 843 if (request == PTRACE_SYSCALL) 844 set_task_syscall_work(child, SYSCALL_TRACE); 845 else 846 clear_task_syscall_work(child, SYSCALL_TRACE); 847 848 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 849 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 850 set_task_syscall_work(child, SYSCALL_EMU); 851 else 852 clear_task_syscall_work(child, SYSCALL_EMU); 853 #endif 854 855 if (is_singleblock(request)) { 856 if (unlikely(!arch_has_block_step())) 857 return -EIO; 858 user_enable_block_step(child); 859 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 860 if (unlikely(!arch_has_single_step())) 861 return -EIO; 862 user_enable_single_step(child); 863 } else { 864 user_disable_single_step(child); 865 } 866 867 /* 868 * Change ->exit_code and ->state under siglock to avoid the race 869 * with wait_task_stopped() in between; a non-zero ->exit_code will 870 * wrongly look like another report from tracee. 871 * 872 * Note that we need siglock even if ->exit_code == data and/or this 873 * status was not reported yet, the new status must not be cleared by 874 * wait_task_stopped() after resume. 875 * 876 * If data == 0 we do not care if wait_task_stopped() reports the old 877 * status and clears the code too; this can't race with the tracee, it 878 * takes siglock after resume. 879 */ 880 need_siglock = data && !thread_group_empty(current); 881 if (need_siglock) 882 spin_lock_irq(&child->sighand->siglock); 883 child->exit_code = data; 884 wake_up_state(child, __TASK_TRACED); 885 if (need_siglock) 886 spin_unlock_irq(&child->sighand->siglock); 887 888 return 0; 889 } 890 891 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 892 893 static const struct user_regset * 894 find_regset(const struct user_regset_view *view, unsigned int type) 895 { 896 const struct user_regset *regset; 897 int n; 898 899 for (n = 0; n < view->n; ++n) { 900 regset = view->regsets + n; 901 if (regset->core_note_type == type) 902 return regset; 903 } 904 905 return NULL; 906 } 907 908 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 909 struct iovec *kiov) 910 { 911 const struct user_regset_view *view = task_user_regset_view(task); 912 const struct user_regset *regset = find_regset(view, type); 913 int regset_no; 914 915 if (!regset || (kiov->iov_len % regset->size) != 0) 916 return -EINVAL; 917 918 regset_no = regset - view->regsets; 919 kiov->iov_len = min(kiov->iov_len, 920 (__kernel_size_t) (regset->n * regset->size)); 921 922 if (req == PTRACE_GETREGSET) 923 return copy_regset_to_user(task, view, regset_no, 0, 924 kiov->iov_len, kiov->iov_base); 925 else 926 return copy_regset_from_user(task, view, regset_no, 0, 927 kiov->iov_len, kiov->iov_base); 928 } 929 930 /* 931 * This is declared in linux/regset.h and defined in machine-dependent 932 * code. We put the export here, near the primary machine-neutral use, 933 * to ensure no machine forgets it. 934 */ 935 EXPORT_SYMBOL_GPL(task_user_regset_view); 936 937 static unsigned long 938 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 939 struct ptrace_syscall_info *info) 940 { 941 unsigned long args[ARRAY_SIZE(info->entry.args)]; 942 int i; 943 944 info->op = PTRACE_SYSCALL_INFO_ENTRY; 945 info->entry.nr = syscall_get_nr(child, regs); 946 syscall_get_arguments(child, regs, args); 947 for (i = 0; i < ARRAY_SIZE(args); i++) 948 info->entry.args[i] = args[i]; 949 950 /* args is the last field in struct ptrace_syscall_info.entry */ 951 return offsetofend(struct ptrace_syscall_info, entry.args); 952 } 953 954 static unsigned long 955 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 956 struct ptrace_syscall_info *info) 957 { 958 /* 959 * As struct ptrace_syscall_info.entry is currently a subset 960 * of struct ptrace_syscall_info.seccomp, it makes sense to 961 * initialize that subset using ptrace_get_syscall_info_entry(). 962 * This can be reconsidered in the future if these structures 963 * diverge significantly enough. 964 */ 965 ptrace_get_syscall_info_entry(child, regs, info); 966 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 967 info->seccomp.ret_data = child->ptrace_message; 968 969 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 970 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 971 } 972 973 static unsigned long 974 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 975 struct ptrace_syscall_info *info) 976 { 977 info->op = PTRACE_SYSCALL_INFO_EXIT; 978 info->exit.rval = syscall_get_error(child, regs); 979 info->exit.is_error = !!info->exit.rval; 980 if (!info->exit.is_error) 981 info->exit.rval = syscall_get_return_value(child, regs); 982 983 /* is_error is the last field in struct ptrace_syscall_info.exit */ 984 return offsetofend(struct ptrace_syscall_info, exit.is_error); 985 } 986 987 static int 988 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 989 void __user *datavp) 990 { 991 struct pt_regs *regs = task_pt_regs(child); 992 struct ptrace_syscall_info info = { 993 .op = PTRACE_SYSCALL_INFO_NONE, 994 .arch = syscall_get_arch(child), 995 .instruction_pointer = instruction_pointer(regs), 996 .stack_pointer = user_stack_pointer(regs), 997 }; 998 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 999 unsigned long write_size; 1000 1001 /* 1002 * This does not need lock_task_sighand() to access 1003 * child->last_siginfo because ptrace_freeze_traced() 1004 * called earlier by ptrace_check_attach() ensures that 1005 * the tracee cannot go away and clear its last_siginfo. 1006 */ 1007 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 1008 case SIGTRAP | 0x80: 1009 switch (child->ptrace_message) { 1010 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 1011 actual_size = ptrace_get_syscall_info_entry(child, regs, 1012 &info); 1013 break; 1014 case PTRACE_EVENTMSG_SYSCALL_EXIT: 1015 actual_size = ptrace_get_syscall_info_exit(child, regs, 1016 &info); 1017 break; 1018 } 1019 break; 1020 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 1021 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 1022 &info); 1023 break; 1024 } 1025 1026 write_size = min(actual_size, user_size); 1027 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 1028 } 1029 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 1030 1031 int ptrace_request(struct task_struct *child, long request, 1032 unsigned long addr, unsigned long data) 1033 { 1034 bool seized = child->ptrace & PT_SEIZED; 1035 int ret = -EIO; 1036 kernel_siginfo_t siginfo, *si; 1037 void __user *datavp = (void __user *) data; 1038 unsigned long __user *datalp = datavp; 1039 unsigned long flags; 1040 1041 switch (request) { 1042 case PTRACE_PEEKTEXT: 1043 case PTRACE_PEEKDATA: 1044 return generic_ptrace_peekdata(child, addr, data); 1045 case PTRACE_POKETEXT: 1046 case PTRACE_POKEDATA: 1047 return generic_ptrace_pokedata(child, addr, data); 1048 1049 #ifdef PTRACE_OLDSETOPTIONS 1050 case PTRACE_OLDSETOPTIONS: 1051 #endif 1052 case PTRACE_SETOPTIONS: 1053 ret = ptrace_setoptions(child, data); 1054 break; 1055 case PTRACE_GETEVENTMSG: 1056 ret = put_user(child->ptrace_message, datalp); 1057 break; 1058 1059 case PTRACE_PEEKSIGINFO: 1060 ret = ptrace_peek_siginfo(child, addr, data); 1061 break; 1062 1063 case PTRACE_GETSIGINFO: 1064 ret = ptrace_getsiginfo(child, &siginfo); 1065 if (!ret) 1066 ret = copy_siginfo_to_user(datavp, &siginfo); 1067 break; 1068 1069 case PTRACE_SETSIGINFO: 1070 ret = copy_siginfo_from_user(&siginfo, datavp); 1071 if (!ret) 1072 ret = ptrace_setsiginfo(child, &siginfo); 1073 break; 1074 1075 case PTRACE_GETSIGMASK: { 1076 sigset_t *mask; 1077 1078 if (addr != sizeof(sigset_t)) { 1079 ret = -EINVAL; 1080 break; 1081 } 1082 1083 if (test_tsk_restore_sigmask(child)) 1084 mask = &child->saved_sigmask; 1085 else 1086 mask = &child->blocked; 1087 1088 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1089 ret = -EFAULT; 1090 else 1091 ret = 0; 1092 1093 break; 1094 } 1095 1096 case PTRACE_SETSIGMASK: { 1097 sigset_t new_set; 1098 1099 if (addr != sizeof(sigset_t)) { 1100 ret = -EINVAL; 1101 break; 1102 } 1103 1104 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1105 ret = -EFAULT; 1106 break; 1107 } 1108 1109 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1110 1111 /* 1112 * Every thread does recalc_sigpending() after resume, so 1113 * retarget_shared_pending() and recalc_sigpending() are not 1114 * called here. 1115 */ 1116 spin_lock_irq(&child->sighand->siglock); 1117 child->blocked = new_set; 1118 spin_unlock_irq(&child->sighand->siglock); 1119 1120 clear_tsk_restore_sigmask(child); 1121 1122 ret = 0; 1123 break; 1124 } 1125 1126 case PTRACE_INTERRUPT: 1127 /* 1128 * Stop tracee without any side-effect on signal or job 1129 * control. At least one trap is guaranteed to happen 1130 * after this request. If @child is already trapped, the 1131 * current trap is not disturbed and another trap will 1132 * happen after the current trap is ended with PTRACE_CONT. 1133 * 1134 * The actual trap might not be PTRACE_EVENT_STOP trap but 1135 * the pending condition is cleared regardless. 1136 */ 1137 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1138 break; 1139 1140 /* 1141 * INTERRUPT doesn't disturb existing trap sans one 1142 * exception. If ptracer issued LISTEN for the current 1143 * STOP, this INTERRUPT should clear LISTEN and re-trap 1144 * tracee into STOP. 1145 */ 1146 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1147 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1148 1149 unlock_task_sighand(child, &flags); 1150 ret = 0; 1151 break; 1152 1153 case PTRACE_LISTEN: 1154 /* 1155 * Listen for events. Tracee must be in STOP. It's not 1156 * resumed per-se but is not considered to be in TRACED by 1157 * wait(2) or ptrace(2). If an async event (e.g. group 1158 * stop state change) happens, tracee will enter STOP trap 1159 * again. Alternatively, ptracer can issue INTERRUPT to 1160 * finish listening and re-trap tracee into STOP. 1161 */ 1162 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1163 break; 1164 1165 si = child->last_siginfo; 1166 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1167 child->jobctl |= JOBCTL_LISTENING; 1168 /* 1169 * If NOTIFY is set, it means event happened between 1170 * start of this trap and now. Trigger re-trap. 1171 */ 1172 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1173 ptrace_signal_wake_up(child, true); 1174 ret = 0; 1175 } 1176 unlock_task_sighand(child, &flags); 1177 break; 1178 1179 case PTRACE_DETACH: /* detach a process that was attached. */ 1180 ret = ptrace_detach(child, data); 1181 break; 1182 1183 #ifdef CONFIG_BINFMT_ELF_FDPIC 1184 case PTRACE_GETFDPIC: { 1185 struct mm_struct *mm = get_task_mm(child); 1186 unsigned long tmp = 0; 1187 1188 ret = -ESRCH; 1189 if (!mm) 1190 break; 1191 1192 switch (addr) { 1193 case PTRACE_GETFDPIC_EXEC: 1194 tmp = mm->context.exec_fdpic_loadmap; 1195 break; 1196 case PTRACE_GETFDPIC_INTERP: 1197 tmp = mm->context.interp_fdpic_loadmap; 1198 break; 1199 default: 1200 break; 1201 } 1202 mmput(mm); 1203 1204 ret = put_user(tmp, datalp); 1205 break; 1206 } 1207 #endif 1208 1209 #ifdef PTRACE_SINGLESTEP 1210 case PTRACE_SINGLESTEP: 1211 #endif 1212 #ifdef PTRACE_SINGLEBLOCK 1213 case PTRACE_SINGLEBLOCK: 1214 #endif 1215 #ifdef PTRACE_SYSEMU 1216 case PTRACE_SYSEMU: 1217 case PTRACE_SYSEMU_SINGLESTEP: 1218 #endif 1219 case PTRACE_SYSCALL: 1220 case PTRACE_CONT: 1221 return ptrace_resume(child, request, data); 1222 1223 case PTRACE_KILL: 1224 if (child->exit_state) /* already dead */ 1225 return 0; 1226 return ptrace_resume(child, request, SIGKILL); 1227 1228 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1229 case PTRACE_GETREGSET: 1230 case PTRACE_SETREGSET: { 1231 struct iovec kiov; 1232 struct iovec __user *uiov = datavp; 1233 1234 if (!access_ok(uiov, sizeof(*uiov))) 1235 return -EFAULT; 1236 1237 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1238 __get_user(kiov.iov_len, &uiov->iov_len)) 1239 return -EFAULT; 1240 1241 ret = ptrace_regset(child, request, addr, &kiov); 1242 if (!ret) 1243 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1244 break; 1245 } 1246 1247 case PTRACE_GET_SYSCALL_INFO: 1248 ret = ptrace_get_syscall_info(child, addr, datavp); 1249 break; 1250 #endif 1251 1252 case PTRACE_SECCOMP_GET_FILTER: 1253 ret = seccomp_get_filter(child, addr, datavp); 1254 break; 1255 1256 case PTRACE_SECCOMP_GET_METADATA: 1257 ret = seccomp_get_metadata(child, addr, datavp); 1258 break; 1259 1260 #ifdef CONFIG_RSEQ 1261 case PTRACE_GET_RSEQ_CONFIGURATION: 1262 ret = ptrace_get_rseq_configuration(child, addr, datavp); 1263 break; 1264 #endif 1265 1266 default: 1267 break; 1268 } 1269 1270 return ret; 1271 } 1272 1273 #ifndef arch_ptrace_attach 1274 #define arch_ptrace_attach(child) do { } while (0) 1275 #endif 1276 1277 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1278 unsigned long, data) 1279 { 1280 struct task_struct *child; 1281 long ret; 1282 1283 if (request == PTRACE_TRACEME) { 1284 ret = ptrace_traceme(); 1285 if (!ret) 1286 arch_ptrace_attach(current); 1287 goto out; 1288 } 1289 1290 child = find_get_task_by_vpid(pid); 1291 if (!child) { 1292 ret = -ESRCH; 1293 goto out; 1294 } 1295 1296 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1297 ret = ptrace_attach(child, request, addr, data); 1298 /* 1299 * Some architectures need to do book-keeping after 1300 * a ptrace attach. 1301 */ 1302 if (!ret) 1303 arch_ptrace_attach(child); 1304 goto out_put_task_struct; 1305 } 1306 1307 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1308 request == PTRACE_INTERRUPT); 1309 if (ret < 0) 1310 goto out_put_task_struct; 1311 1312 ret = arch_ptrace(child, request, addr, data); 1313 if (ret || request != PTRACE_DETACH) 1314 ptrace_unfreeze_traced(child); 1315 1316 out_put_task_struct: 1317 put_task_struct(child); 1318 out: 1319 return ret; 1320 } 1321 1322 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1323 unsigned long data) 1324 { 1325 unsigned long tmp; 1326 int copied; 1327 1328 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1329 if (copied != sizeof(tmp)) 1330 return -EIO; 1331 return put_user(tmp, (unsigned long __user *)data); 1332 } 1333 1334 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1335 unsigned long data) 1336 { 1337 int copied; 1338 1339 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1340 FOLL_FORCE | FOLL_WRITE); 1341 return (copied == sizeof(data)) ? 0 : -EIO; 1342 } 1343 1344 #if defined CONFIG_COMPAT 1345 1346 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1347 compat_ulong_t addr, compat_ulong_t data) 1348 { 1349 compat_ulong_t __user *datap = compat_ptr(data); 1350 compat_ulong_t word; 1351 kernel_siginfo_t siginfo; 1352 int ret; 1353 1354 switch (request) { 1355 case PTRACE_PEEKTEXT: 1356 case PTRACE_PEEKDATA: 1357 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1358 FOLL_FORCE); 1359 if (ret != sizeof(word)) 1360 ret = -EIO; 1361 else 1362 ret = put_user(word, datap); 1363 break; 1364 1365 case PTRACE_POKETEXT: 1366 case PTRACE_POKEDATA: 1367 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1368 FOLL_FORCE | FOLL_WRITE); 1369 ret = (ret != sizeof(data) ? -EIO : 0); 1370 break; 1371 1372 case PTRACE_GETEVENTMSG: 1373 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1374 break; 1375 1376 case PTRACE_GETSIGINFO: 1377 ret = ptrace_getsiginfo(child, &siginfo); 1378 if (!ret) 1379 ret = copy_siginfo_to_user32( 1380 (struct compat_siginfo __user *) datap, 1381 &siginfo); 1382 break; 1383 1384 case PTRACE_SETSIGINFO: 1385 ret = copy_siginfo_from_user32( 1386 &siginfo, (struct compat_siginfo __user *) datap); 1387 if (!ret) 1388 ret = ptrace_setsiginfo(child, &siginfo); 1389 break; 1390 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1391 case PTRACE_GETREGSET: 1392 case PTRACE_SETREGSET: 1393 { 1394 struct iovec kiov; 1395 struct compat_iovec __user *uiov = 1396 (struct compat_iovec __user *) datap; 1397 compat_uptr_t ptr; 1398 compat_size_t len; 1399 1400 if (!access_ok(uiov, sizeof(*uiov))) 1401 return -EFAULT; 1402 1403 if (__get_user(ptr, &uiov->iov_base) || 1404 __get_user(len, &uiov->iov_len)) 1405 return -EFAULT; 1406 1407 kiov.iov_base = compat_ptr(ptr); 1408 kiov.iov_len = len; 1409 1410 ret = ptrace_regset(child, request, addr, &kiov); 1411 if (!ret) 1412 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1413 break; 1414 } 1415 #endif 1416 1417 default: 1418 ret = ptrace_request(child, request, addr, data); 1419 } 1420 1421 return ret; 1422 } 1423 1424 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1425 compat_long_t, addr, compat_long_t, data) 1426 { 1427 struct task_struct *child; 1428 long ret; 1429 1430 if (request == PTRACE_TRACEME) { 1431 ret = ptrace_traceme(); 1432 goto out; 1433 } 1434 1435 child = find_get_task_by_vpid(pid); 1436 if (!child) { 1437 ret = -ESRCH; 1438 goto out; 1439 } 1440 1441 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1442 ret = ptrace_attach(child, request, addr, data); 1443 /* 1444 * Some architectures need to do book-keeping after 1445 * a ptrace attach. 1446 */ 1447 if (!ret) 1448 arch_ptrace_attach(child); 1449 goto out_put_task_struct; 1450 } 1451 1452 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1453 request == PTRACE_INTERRUPT); 1454 if (!ret) { 1455 ret = compat_arch_ptrace(child, request, addr, data); 1456 if (ret || request != PTRACE_DETACH) 1457 ptrace_unfreeze_traced(child); 1458 } 1459 1460 out_put_task_struct: 1461 put_task_struct(child); 1462 out: 1463 return ret; 1464 } 1465 #endif /* CONFIG_COMPAT */ 1466