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 check_ptrace_options(unsigned long data) 375 { 376 if (data & ~(unsigned long)PTRACE_O_MASK) 377 return -EINVAL; 378 379 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { 380 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || 381 !IS_ENABLED(CONFIG_SECCOMP)) 382 return -EINVAL; 383 384 if (!capable(CAP_SYS_ADMIN)) 385 return -EPERM; 386 387 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || 388 current->ptrace & PT_SUSPEND_SECCOMP) 389 return -EPERM; 390 } 391 return 0; 392 } 393 394 static int ptrace_attach(struct task_struct *task, long request, 395 unsigned long addr, 396 unsigned long flags) 397 { 398 bool seize = (request == PTRACE_SEIZE); 399 int retval; 400 401 retval = -EIO; 402 if (seize) { 403 if (addr != 0) 404 goto out; 405 /* 406 * This duplicates the check in check_ptrace_options() because 407 * ptrace_attach() and ptrace_setoptions() have historically 408 * used different error codes for unknown ptrace options. 409 */ 410 if (flags & ~(unsigned long)PTRACE_O_MASK) 411 goto out; 412 retval = check_ptrace_options(flags); 413 if (retval) 414 return retval; 415 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 416 } else { 417 flags = PT_PTRACED; 418 } 419 420 audit_ptrace(task); 421 422 retval = -EPERM; 423 if (unlikely(task->flags & PF_KTHREAD)) 424 goto out; 425 if (same_thread_group(task, current)) 426 goto out; 427 428 /* 429 * Protect exec's credential calculations against our interference; 430 * SUID, SGID and LSM creds get determined differently 431 * under ptrace. 432 */ 433 retval = -ERESTARTNOINTR; 434 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 435 goto out; 436 437 task_lock(task); 438 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); 439 task_unlock(task); 440 if (retval) 441 goto unlock_creds; 442 443 write_lock_irq(&tasklist_lock); 444 retval = -EPERM; 445 if (unlikely(task->exit_state)) 446 goto unlock_tasklist; 447 if (task->ptrace) 448 goto unlock_tasklist; 449 450 task->ptrace = flags; 451 452 ptrace_link(task, current); 453 454 /* SEIZE doesn't trap tracee on attach */ 455 if (!seize) 456 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task); 457 458 spin_lock(&task->sighand->siglock); 459 460 /* 461 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 462 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 463 * will be cleared if the child completes the transition or any 464 * event which clears the group stop states happens. We'll wait 465 * for the transition to complete before returning from this 466 * function. 467 * 468 * This hides STOPPED -> RUNNING -> TRACED transition from the 469 * attaching thread but a different thread in the same group can 470 * still observe the transient RUNNING state. IOW, if another 471 * thread's WNOHANG wait(2) on the stopped tracee races against 472 * ATTACH, the wait(2) may fail due to the transient RUNNING. 473 * 474 * The following task_is_stopped() test is safe as both transitions 475 * in and out of STOPPED are protected by siglock. 476 */ 477 if (task_is_stopped(task) && 478 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 479 signal_wake_up_state(task, __TASK_STOPPED); 480 481 spin_unlock(&task->sighand->siglock); 482 483 retval = 0; 484 unlock_tasklist: 485 write_unlock_irq(&tasklist_lock); 486 unlock_creds: 487 mutex_unlock(&task->signal->cred_guard_mutex); 488 out: 489 if (!retval) { 490 /* 491 * We do not bother to change retval or clear JOBCTL_TRAPPING 492 * if wait_on_bit() was interrupted by SIGKILL. The tracer will 493 * not return to user-mode, it will exit and clear this bit in 494 * __ptrace_unlink() if it wasn't already cleared by the tracee; 495 * and until then nobody can ptrace this task. 496 */ 497 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE); 498 proc_ptrace_connector(task, PTRACE_ATTACH); 499 } 500 501 return retval; 502 } 503 504 /** 505 * ptrace_traceme -- helper for PTRACE_TRACEME 506 * 507 * Performs checks and sets PT_PTRACED. 508 * Should be used by all ptrace implementations for PTRACE_TRACEME. 509 */ 510 static int ptrace_traceme(void) 511 { 512 int ret = -EPERM; 513 514 write_lock_irq(&tasklist_lock); 515 /* Are we already being traced? */ 516 if (!current->ptrace) { 517 ret = security_ptrace_traceme(current->parent); 518 /* 519 * Check PF_EXITING to ensure ->real_parent has not passed 520 * exit_ptrace(). Otherwise we don't report the error but 521 * pretend ->real_parent untraces us right after return. 522 */ 523 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 524 current->ptrace = PT_PTRACED; 525 ptrace_link(current, current->real_parent); 526 } 527 } 528 write_unlock_irq(&tasklist_lock); 529 530 return ret; 531 } 532 533 /* 534 * Called with irqs disabled, returns true if childs should reap themselves. 535 */ 536 static int ignoring_children(struct sighand_struct *sigh) 537 { 538 int ret; 539 spin_lock(&sigh->siglock); 540 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 541 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 542 spin_unlock(&sigh->siglock); 543 return ret; 544 } 545 546 /* 547 * Called with tasklist_lock held for writing. 548 * Unlink a traced task, and clean it up if it was a traced zombie. 549 * Return true if it needs to be reaped with release_task(). 550 * (We can't call release_task() here because we already hold tasklist_lock.) 551 * 552 * If it's a zombie, our attachedness prevented normal parent notification 553 * or self-reaping. Do notification now if it would have happened earlier. 554 * If it should reap itself, return true. 555 * 556 * If it's our own child, there is no notification to do. But if our normal 557 * children self-reap, then this child was prevented by ptrace and we must 558 * reap it now, in that case we must also wake up sub-threads sleeping in 559 * do_wait(). 560 */ 561 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 562 { 563 bool dead; 564 565 __ptrace_unlink(p); 566 567 if (p->exit_state != EXIT_ZOMBIE) 568 return false; 569 570 dead = !thread_group_leader(p); 571 572 if (!dead && thread_group_empty(p)) { 573 if (!same_thread_group(p->real_parent, tracer)) 574 dead = do_notify_parent(p, p->exit_signal); 575 else if (ignoring_children(tracer->sighand)) { 576 __wake_up_parent(p, tracer); 577 dead = true; 578 } 579 } 580 /* Mark it as in the process of being reaped. */ 581 if (dead) 582 p->exit_state = EXIT_DEAD; 583 return dead; 584 } 585 586 static int ptrace_detach(struct task_struct *child, unsigned int data) 587 { 588 if (!valid_signal(data)) 589 return -EIO; 590 591 /* Architecture-specific hardware disable .. */ 592 ptrace_disable(child); 593 594 write_lock_irq(&tasklist_lock); 595 /* 596 * We rely on ptrace_freeze_traced(). It can't be killed and 597 * untraced by another thread, it can't be a zombie. 598 */ 599 WARN_ON(!child->ptrace || child->exit_state); 600 /* 601 * tasklist_lock avoids the race with wait_task_stopped(), see 602 * the comment in ptrace_resume(). 603 */ 604 child->exit_code = data; 605 __ptrace_detach(current, child); 606 write_unlock_irq(&tasklist_lock); 607 608 proc_ptrace_connector(child, PTRACE_DETACH); 609 610 return 0; 611 } 612 613 /* 614 * Detach all tasks we were using ptrace on. Called with tasklist held 615 * for writing. 616 */ 617 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 618 { 619 struct task_struct *p, *n; 620 621 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 622 if (unlikely(p->ptrace & PT_EXITKILL)) 623 send_sig_info(SIGKILL, SEND_SIG_PRIV, p); 624 625 if (__ptrace_detach(tracer, p)) 626 list_add(&p->ptrace_entry, dead); 627 } 628 } 629 630 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *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 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE); 640 641 if (!retval) { 642 if (copied) 643 break; 644 return -EIO; 645 } 646 if (copy_to_user(dst, buf, retval)) 647 return -EFAULT; 648 copied += retval; 649 src += retval; 650 dst += retval; 651 len -= retval; 652 } 653 return copied; 654 } 655 656 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 657 { 658 int copied = 0; 659 660 while (len > 0) { 661 char buf[128]; 662 int this_len, retval; 663 664 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 665 if (copy_from_user(buf, src, this_len)) 666 return -EFAULT; 667 retval = ptrace_access_vm(tsk, dst, buf, this_len, 668 FOLL_FORCE | FOLL_WRITE); 669 if (!retval) { 670 if (copied) 671 break; 672 return -EIO; 673 } 674 copied += retval; 675 src += retval; 676 dst += retval; 677 len -= retval; 678 } 679 return copied; 680 } 681 682 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 683 { 684 unsigned flags; 685 int ret; 686 687 ret = check_ptrace_options(data); 688 if (ret) 689 return ret; 690 691 /* Avoid intermediate state when all opts are cleared */ 692 flags = child->ptrace; 693 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 694 flags |= (data << PT_OPT_FLAG_SHIFT); 695 child->ptrace = flags; 696 697 return 0; 698 } 699 700 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info) 701 { 702 unsigned long flags; 703 int error = -ESRCH; 704 705 if (lock_task_sighand(child, &flags)) { 706 error = -EINVAL; 707 if (likely(child->last_siginfo != NULL)) { 708 copy_siginfo(info, child->last_siginfo); 709 error = 0; 710 } 711 unlock_task_sighand(child, &flags); 712 } 713 return error; 714 } 715 716 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info) 717 { 718 unsigned long flags; 719 int error = -ESRCH; 720 721 if (lock_task_sighand(child, &flags)) { 722 error = -EINVAL; 723 if (likely(child->last_siginfo != NULL)) { 724 copy_siginfo(child->last_siginfo, info); 725 error = 0; 726 } 727 unlock_task_sighand(child, &flags); 728 } 729 return error; 730 } 731 732 static int ptrace_peek_siginfo(struct task_struct *child, 733 unsigned long addr, 734 unsigned long data) 735 { 736 struct ptrace_peeksiginfo_args arg; 737 struct sigpending *pending; 738 struct sigqueue *q; 739 int ret, i; 740 741 ret = copy_from_user(&arg, (void __user *) addr, 742 sizeof(struct ptrace_peeksiginfo_args)); 743 if (ret) 744 return -EFAULT; 745 746 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 747 return -EINVAL; /* unknown flags */ 748 749 if (arg.nr < 0) 750 return -EINVAL; 751 752 /* Ensure arg.off fits in an unsigned long */ 753 if (arg.off > ULONG_MAX) 754 return 0; 755 756 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 757 pending = &child->signal->shared_pending; 758 else 759 pending = &child->pending; 760 761 for (i = 0; i < arg.nr; ) { 762 kernel_siginfo_t info; 763 unsigned long off = arg.off + i; 764 bool found = false; 765 766 spin_lock_irq(&child->sighand->siglock); 767 list_for_each_entry(q, &pending->list, list) { 768 if (!off--) { 769 found = true; 770 copy_siginfo(&info, &q->info); 771 break; 772 } 773 } 774 spin_unlock_irq(&child->sighand->siglock); 775 776 if (!found) /* beyond the end of the list */ 777 break; 778 779 #ifdef CONFIG_COMPAT 780 if (unlikely(in_compat_syscall())) { 781 compat_siginfo_t __user *uinfo = compat_ptr(data); 782 783 if (copy_siginfo_to_user32(uinfo, &info)) { 784 ret = -EFAULT; 785 break; 786 } 787 788 } else 789 #endif 790 { 791 siginfo_t __user *uinfo = (siginfo_t __user *) data; 792 793 if (copy_siginfo_to_user(uinfo, &info)) { 794 ret = -EFAULT; 795 break; 796 } 797 } 798 799 data += sizeof(siginfo_t); 800 i++; 801 802 if (signal_pending(current)) 803 break; 804 805 cond_resched(); 806 } 807 808 if (i > 0) 809 return i; 810 811 return ret; 812 } 813 814 #ifdef CONFIG_RSEQ 815 static long ptrace_get_rseq_configuration(struct task_struct *task, 816 unsigned long size, void __user *data) 817 { 818 struct ptrace_rseq_configuration conf = { 819 .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, 820 .rseq_abi_size = sizeof(*task->rseq), 821 .signature = task->rseq_sig, 822 .flags = 0, 823 }; 824 825 size = min_t(unsigned long, size, sizeof(conf)); 826 if (copy_to_user(data, &conf, size)) 827 return -EFAULT; 828 return sizeof(conf); 829 } 830 #endif 831 832 #ifdef PTRACE_SINGLESTEP 833 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 834 #else 835 #define is_singlestep(request) 0 836 #endif 837 838 #ifdef PTRACE_SINGLEBLOCK 839 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 840 #else 841 #define is_singleblock(request) 0 842 #endif 843 844 #ifdef PTRACE_SYSEMU 845 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 846 #else 847 #define is_sysemu_singlestep(request) 0 848 #endif 849 850 static int ptrace_resume(struct task_struct *child, long request, 851 unsigned long data) 852 { 853 bool need_siglock; 854 855 if (!valid_signal(data)) 856 return -EIO; 857 858 if (request == PTRACE_SYSCALL) 859 set_task_syscall_work(child, SYSCALL_TRACE); 860 else 861 clear_task_syscall_work(child, SYSCALL_TRACE); 862 863 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU) 864 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 865 set_task_syscall_work(child, SYSCALL_EMU); 866 else 867 clear_task_syscall_work(child, SYSCALL_EMU); 868 #endif 869 870 if (is_singleblock(request)) { 871 if (unlikely(!arch_has_block_step())) 872 return -EIO; 873 user_enable_block_step(child); 874 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 875 if (unlikely(!arch_has_single_step())) 876 return -EIO; 877 user_enable_single_step(child); 878 } else { 879 user_disable_single_step(child); 880 } 881 882 /* 883 * Change ->exit_code and ->state under siglock to avoid the race 884 * with wait_task_stopped() in between; a non-zero ->exit_code will 885 * wrongly look like another report from tracee. 886 * 887 * Note that we need siglock even if ->exit_code == data and/or this 888 * status was not reported yet, the new status must not be cleared by 889 * wait_task_stopped() after resume. 890 * 891 * If data == 0 we do not care if wait_task_stopped() reports the old 892 * status and clears the code too; this can't race with the tracee, it 893 * takes siglock after resume. 894 */ 895 need_siglock = data && !thread_group_empty(current); 896 if (need_siglock) 897 spin_lock_irq(&child->sighand->siglock); 898 child->exit_code = data; 899 wake_up_state(child, __TASK_TRACED); 900 if (need_siglock) 901 spin_unlock_irq(&child->sighand->siglock); 902 903 return 0; 904 } 905 906 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 907 908 static const struct user_regset * 909 find_regset(const struct user_regset_view *view, unsigned int type) 910 { 911 const struct user_regset *regset; 912 int n; 913 914 for (n = 0; n < view->n; ++n) { 915 regset = view->regsets + n; 916 if (regset->core_note_type == type) 917 return regset; 918 } 919 920 return NULL; 921 } 922 923 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 924 struct iovec *kiov) 925 { 926 const struct user_regset_view *view = task_user_regset_view(task); 927 const struct user_regset *regset = find_regset(view, type); 928 int regset_no; 929 930 if (!regset || (kiov->iov_len % regset->size) != 0) 931 return -EINVAL; 932 933 regset_no = regset - view->regsets; 934 kiov->iov_len = min(kiov->iov_len, 935 (__kernel_size_t) (regset->n * regset->size)); 936 937 if (req == PTRACE_GETREGSET) 938 return copy_regset_to_user(task, view, regset_no, 0, 939 kiov->iov_len, kiov->iov_base); 940 else 941 return copy_regset_from_user(task, view, regset_no, 0, 942 kiov->iov_len, kiov->iov_base); 943 } 944 945 /* 946 * This is declared in linux/regset.h and defined in machine-dependent 947 * code. We put the export here, near the primary machine-neutral use, 948 * to ensure no machine forgets it. 949 */ 950 EXPORT_SYMBOL_GPL(task_user_regset_view); 951 952 static unsigned long 953 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs, 954 struct ptrace_syscall_info *info) 955 { 956 unsigned long args[ARRAY_SIZE(info->entry.args)]; 957 int i; 958 959 info->op = PTRACE_SYSCALL_INFO_ENTRY; 960 info->entry.nr = syscall_get_nr(child, regs); 961 syscall_get_arguments(child, regs, args); 962 for (i = 0; i < ARRAY_SIZE(args); i++) 963 info->entry.args[i] = args[i]; 964 965 /* args is the last field in struct ptrace_syscall_info.entry */ 966 return offsetofend(struct ptrace_syscall_info, entry.args); 967 } 968 969 static unsigned long 970 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs, 971 struct ptrace_syscall_info *info) 972 { 973 /* 974 * As struct ptrace_syscall_info.entry is currently a subset 975 * of struct ptrace_syscall_info.seccomp, it makes sense to 976 * initialize that subset using ptrace_get_syscall_info_entry(). 977 * This can be reconsidered in the future if these structures 978 * diverge significantly enough. 979 */ 980 ptrace_get_syscall_info_entry(child, regs, info); 981 info->op = PTRACE_SYSCALL_INFO_SECCOMP; 982 info->seccomp.ret_data = child->ptrace_message; 983 984 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */ 985 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data); 986 } 987 988 static unsigned long 989 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs, 990 struct ptrace_syscall_info *info) 991 { 992 info->op = PTRACE_SYSCALL_INFO_EXIT; 993 info->exit.rval = syscall_get_error(child, regs); 994 info->exit.is_error = !!info->exit.rval; 995 if (!info->exit.is_error) 996 info->exit.rval = syscall_get_return_value(child, regs); 997 998 /* is_error is the last field in struct ptrace_syscall_info.exit */ 999 return offsetofend(struct ptrace_syscall_info, exit.is_error); 1000 } 1001 1002 static int 1003 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, 1004 void __user *datavp) 1005 { 1006 struct pt_regs *regs = task_pt_regs(child); 1007 struct ptrace_syscall_info info = { 1008 .op = PTRACE_SYSCALL_INFO_NONE, 1009 .arch = syscall_get_arch(child), 1010 .instruction_pointer = instruction_pointer(regs), 1011 .stack_pointer = user_stack_pointer(regs), 1012 }; 1013 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); 1014 unsigned long write_size; 1015 1016 /* 1017 * This does not need lock_task_sighand() to access 1018 * child->last_siginfo because ptrace_freeze_traced() 1019 * called earlier by ptrace_check_attach() ensures that 1020 * the tracee cannot go away and clear its last_siginfo. 1021 */ 1022 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { 1023 case SIGTRAP | 0x80: 1024 switch (child->ptrace_message) { 1025 case PTRACE_EVENTMSG_SYSCALL_ENTRY: 1026 actual_size = ptrace_get_syscall_info_entry(child, regs, 1027 &info); 1028 break; 1029 case PTRACE_EVENTMSG_SYSCALL_EXIT: 1030 actual_size = ptrace_get_syscall_info_exit(child, regs, 1031 &info); 1032 break; 1033 } 1034 break; 1035 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): 1036 actual_size = ptrace_get_syscall_info_seccomp(child, regs, 1037 &info); 1038 break; 1039 } 1040 1041 write_size = min(actual_size, user_size); 1042 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; 1043 } 1044 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */ 1045 1046 int ptrace_request(struct task_struct *child, long request, 1047 unsigned long addr, unsigned long data) 1048 { 1049 bool seized = child->ptrace & PT_SEIZED; 1050 int ret = -EIO; 1051 kernel_siginfo_t siginfo, *si; 1052 void __user *datavp = (void __user *) data; 1053 unsigned long __user *datalp = datavp; 1054 unsigned long flags; 1055 1056 switch (request) { 1057 case PTRACE_PEEKTEXT: 1058 case PTRACE_PEEKDATA: 1059 return generic_ptrace_peekdata(child, addr, data); 1060 case PTRACE_POKETEXT: 1061 case PTRACE_POKEDATA: 1062 return generic_ptrace_pokedata(child, addr, data); 1063 1064 #ifdef PTRACE_OLDSETOPTIONS 1065 case PTRACE_OLDSETOPTIONS: 1066 #endif 1067 case PTRACE_SETOPTIONS: 1068 ret = ptrace_setoptions(child, data); 1069 break; 1070 case PTRACE_GETEVENTMSG: 1071 ret = put_user(child->ptrace_message, datalp); 1072 break; 1073 1074 case PTRACE_PEEKSIGINFO: 1075 ret = ptrace_peek_siginfo(child, addr, data); 1076 break; 1077 1078 case PTRACE_GETSIGINFO: 1079 ret = ptrace_getsiginfo(child, &siginfo); 1080 if (!ret) 1081 ret = copy_siginfo_to_user(datavp, &siginfo); 1082 break; 1083 1084 case PTRACE_SETSIGINFO: 1085 ret = copy_siginfo_from_user(&siginfo, datavp); 1086 if (!ret) 1087 ret = ptrace_setsiginfo(child, &siginfo); 1088 break; 1089 1090 case PTRACE_GETSIGMASK: { 1091 sigset_t *mask; 1092 1093 if (addr != sizeof(sigset_t)) { 1094 ret = -EINVAL; 1095 break; 1096 } 1097 1098 if (test_tsk_restore_sigmask(child)) 1099 mask = &child->saved_sigmask; 1100 else 1101 mask = &child->blocked; 1102 1103 if (copy_to_user(datavp, mask, sizeof(sigset_t))) 1104 ret = -EFAULT; 1105 else 1106 ret = 0; 1107 1108 break; 1109 } 1110 1111 case PTRACE_SETSIGMASK: { 1112 sigset_t new_set; 1113 1114 if (addr != sizeof(sigset_t)) { 1115 ret = -EINVAL; 1116 break; 1117 } 1118 1119 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 1120 ret = -EFAULT; 1121 break; 1122 } 1123 1124 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1125 1126 /* 1127 * Every thread does recalc_sigpending() after resume, so 1128 * retarget_shared_pending() and recalc_sigpending() are not 1129 * called here. 1130 */ 1131 spin_lock_irq(&child->sighand->siglock); 1132 child->blocked = new_set; 1133 spin_unlock_irq(&child->sighand->siglock); 1134 1135 clear_tsk_restore_sigmask(child); 1136 1137 ret = 0; 1138 break; 1139 } 1140 1141 case PTRACE_INTERRUPT: 1142 /* 1143 * Stop tracee without any side-effect on signal or job 1144 * control. At least one trap is guaranteed to happen 1145 * after this request. If @child is already trapped, the 1146 * current trap is not disturbed and another trap will 1147 * happen after the current trap is ended with PTRACE_CONT. 1148 * 1149 * The actual trap might not be PTRACE_EVENT_STOP trap but 1150 * the pending condition is cleared regardless. 1151 */ 1152 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1153 break; 1154 1155 /* 1156 * INTERRUPT doesn't disturb existing trap sans one 1157 * exception. If ptracer issued LISTEN for the current 1158 * STOP, this INTERRUPT should clear LISTEN and re-trap 1159 * tracee into STOP. 1160 */ 1161 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 1162 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 1163 1164 unlock_task_sighand(child, &flags); 1165 ret = 0; 1166 break; 1167 1168 case PTRACE_LISTEN: 1169 /* 1170 * Listen for events. Tracee must be in STOP. It's not 1171 * resumed per-se but is not considered to be in TRACED by 1172 * wait(2) or ptrace(2). If an async event (e.g. group 1173 * stop state change) happens, tracee will enter STOP trap 1174 * again. Alternatively, ptracer can issue INTERRUPT to 1175 * finish listening and re-trap tracee into STOP. 1176 */ 1177 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 1178 break; 1179 1180 si = child->last_siginfo; 1181 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 1182 child->jobctl |= JOBCTL_LISTENING; 1183 /* 1184 * If NOTIFY is set, it means event happened between 1185 * start of this trap and now. Trigger re-trap. 1186 */ 1187 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 1188 ptrace_signal_wake_up(child, true); 1189 ret = 0; 1190 } 1191 unlock_task_sighand(child, &flags); 1192 break; 1193 1194 case PTRACE_DETACH: /* detach a process that was attached. */ 1195 ret = ptrace_detach(child, data); 1196 break; 1197 1198 #ifdef CONFIG_BINFMT_ELF_FDPIC 1199 case PTRACE_GETFDPIC: { 1200 struct mm_struct *mm = get_task_mm(child); 1201 unsigned long tmp = 0; 1202 1203 ret = -ESRCH; 1204 if (!mm) 1205 break; 1206 1207 switch (addr) { 1208 case PTRACE_GETFDPIC_EXEC: 1209 tmp = mm->context.exec_fdpic_loadmap; 1210 break; 1211 case PTRACE_GETFDPIC_INTERP: 1212 tmp = mm->context.interp_fdpic_loadmap; 1213 break; 1214 default: 1215 break; 1216 } 1217 mmput(mm); 1218 1219 ret = put_user(tmp, datalp); 1220 break; 1221 } 1222 #endif 1223 1224 #ifdef PTRACE_SINGLESTEP 1225 case PTRACE_SINGLESTEP: 1226 #endif 1227 #ifdef PTRACE_SINGLEBLOCK 1228 case PTRACE_SINGLEBLOCK: 1229 #endif 1230 #ifdef PTRACE_SYSEMU 1231 case PTRACE_SYSEMU: 1232 case PTRACE_SYSEMU_SINGLESTEP: 1233 #endif 1234 case PTRACE_SYSCALL: 1235 case PTRACE_CONT: 1236 return ptrace_resume(child, request, data); 1237 1238 case PTRACE_KILL: 1239 if (child->exit_state) /* already dead */ 1240 return 0; 1241 return ptrace_resume(child, request, SIGKILL); 1242 1243 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1244 case PTRACE_GETREGSET: 1245 case PTRACE_SETREGSET: { 1246 struct iovec kiov; 1247 struct iovec __user *uiov = datavp; 1248 1249 if (!access_ok(uiov, sizeof(*uiov))) 1250 return -EFAULT; 1251 1252 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1253 __get_user(kiov.iov_len, &uiov->iov_len)) 1254 return -EFAULT; 1255 1256 ret = ptrace_regset(child, request, addr, &kiov); 1257 if (!ret) 1258 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1259 break; 1260 } 1261 1262 case PTRACE_GET_SYSCALL_INFO: 1263 ret = ptrace_get_syscall_info(child, addr, datavp); 1264 break; 1265 #endif 1266 1267 case PTRACE_SECCOMP_GET_FILTER: 1268 ret = seccomp_get_filter(child, addr, datavp); 1269 break; 1270 1271 case PTRACE_SECCOMP_GET_METADATA: 1272 ret = seccomp_get_metadata(child, addr, datavp); 1273 break; 1274 1275 #ifdef CONFIG_RSEQ 1276 case PTRACE_GET_RSEQ_CONFIGURATION: 1277 ret = ptrace_get_rseq_configuration(child, addr, datavp); 1278 break; 1279 #endif 1280 1281 default: 1282 break; 1283 } 1284 1285 return ret; 1286 } 1287 1288 #ifndef arch_ptrace_attach 1289 #define arch_ptrace_attach(child) do { } while (0) 1290 #endif 1291 1292 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1293 unsigned long, data) 1294 { 1295 struct task_struct *child; 1296 long ret; 1297 1298 if (request == PTRACE_TRACEME) { 1299 ret = ptrace_traceme(); 1300 if (!ret) 1301 arch_ptrace_attach(current); 1302 goto out; 1303 } 1304 1305 child = find_get_task_by_vpid(pid); 1306 if (!child) { 1307 ret = -ESRCH; 1308 goto out; 1309 } 1310 1311 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1312 ret = ptrace_attach(child, request, addr, data); 1313 /* 1314 * Some architectures need to do book-keeping after 1315 * a ptrace attach. 1316 */ 1317 if (!ret) 1318 arch_ptrace_attach(child); 1319 goto out_put_task_struct; 1320 } 1321 1322 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1323 request == PTRACE_INTERRUPT); 1324 if (ret < 0) 1325 goto out_put_task_struct; 1326 1327 ret = arch_ptrace(child, request, addr, data); 1328 if (ret || request != PTRACE_DETACH) 1329 ptrace_unfreeze_traced(child); 1330 1331 out_put_task_struct: 1332 put_task_struct(child); 1333 out: 1334 return ret; 1335 } 1336 1337 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1338 unsigned long data) 1339 { 1340 unsigned long tmp; 1341 int copied; 1342 1343 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE); 1344 if (copied != sizeof(tmp)) 1345 return -EIO; 1346 return put_user(tmp, (unsigned long __user *)data); 1347 } 1348 1349 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1350 unsigned long data) 1351 { 1352 int copied; 1353 1354 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data), 1355 FOLL_FORCE | FOLL_WRITE); 1356 return (copied == sizeof(data)) ? 0 : -EIO; 1357 } 1358 1359 #if defined CONFIG_COMPAT 1360 1361 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1362 compat_ulong_t addr, compat_ulong_t data) 1363 { 1364 compat_ulong_t __user *datap = compat_ptr(data); 1365 compat_ulong_t word; 1366 kernel_siginfo_t siginfo; 1367 int ret; 1368 1369 switch (request) { 1370 case PTRACE_PEEKTEXT: 1371 case PTRACE_PEEKDATA: 1372 ret = ptrace_access_vm(child, addr, &word, sizeof(word), 1373 FOLL_FORCE); 1374 if (ret != sizeof(word)) 1375 ret = -EIO; 1376 else 1377 ret = put_user(word, datap); 1378 break; 1379 1380 case PTRACE_POKETEXT: 1381 case PTRACE_POKEDATA: 1382 ret = ptrace_access_vm(child, addr, &data, sizeof(data), 1383 FOLL_FORCE | FOLL_WRITE); 1384 ret = (ret != sizeof(data) ? -EIO : 0); 1385 break; 1386 1387 case PTRACE_GETEVENTMSG: 1388 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1389 break; 1390 1391 case PTRACE_GETSIGINFO: 1392 ret = ptrace_getsiginfo(child, &siginfo); 1393 if (!ret) 1394 ret = copy_siginfo_to_user32( 1395 (struct compat_siginfo __user *) datap, 1396 &siginfo); 1397 break; 1398 1399 case PTRACE_SETSIGINFO: 1400 ret = copy_siginfo_from_user32( 1401 &siginfo, (struct compat_siginfo __user *) datap); 1402 if (!ret) 1403 ret = ptrace_setsiginfo(child, &siginfo); 1404 break; 1405 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1406 case PTRACE_GETREGSET: 1407 case PTRACE_SETREGSET: 1408 { 1409 struct iovec kiov; 1410 struct compat_iovec __user *uiov = 1411 (struct compat_iovec __user *) datap; 1412 compat_uptr_t ptr; 1413 compat_size_t len; 1414 1415 if (!access_ok(uiov, sizeof(*uiov))) 1416 return -EFAULT; 1417 1418 if (__get_user(ptr, &uiov->iov_base) || 1419 __get_user(len, &uiov->iov_len)) 1420 return -EFAULT; 1421 1422 kiov.iov_base = compat_ptr(ptr); 1423 kiov.iov_len = len; 1424 1425 ret = ptrace_regset(child, request, addr, &kiov); 1426 if (!ret) 1427 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1428 break; 1429 } 1430 #endif 1431 1432 default: 1433 ret = ptrace_request(child, request, addr, data); 1434 } 1435 1436 return ret; 1437 } 1438 1439 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1440 compat_long_t, addr, compat_long_t, data) 1441 { 1442 struct task_struct *child; 1443 long ret; 1444 1445 if (request == PTRACE_TRACEME) { 1446 ret = ptrace_traceme(); 1447 goto out; 1448 } 1449 1450 child = find_get_task_by_vpid(pid); 1451 if (!child) { 1452 ret = -ESRCH; 1453 goto out; 1454 } 1455 1456 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1457 ret = ptrace_attach(child, request, addr, data); 1458 /* 1459 * Some architectures need to do book-keeping after 1460 * a ptrace attach. 1461 */ 1462 if (!ret) 1463 arch_ptrace_attach(child); 1464 goto out_put_task_struct; 1465 } 1466 1467 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1468 request == PTRACE_INTERRUPT); 1469 if (!ret) { 1470 ret = compat_arch_ptrace(child, request, addr, data); 1471 if (ret || request != PTRACE_DETACH) 1472 ptrace_unfreeze_traced(child); 1473 } 1474 1475 out_put_task_struct: 1476 put_task_struct(child); 1477 out: 1478 return ret; 1479 } 1480 #endif /* CONFIG_COMPAT */ 1481