1 /* 2 * linux/kernel/ptrace.c 3 * 4 * (C) Copyright 1999 Linus Torvalds 5 * 6 * Common interfaces for "ptrace()" which we do not want 7 * to continually duplicate across every architecture. 8 */ 9 10 #include <linux/capability.h> 11 #include <linux/export.h> 12 #include <linux/sched.h> 13 #include <linux/errno.h> 14 #include <linux/mm.h> 15 #include <linux/highmem.h> 16 #include <linux/pagemap.h> 17 #include <linux/ptrace.h> 18 #include <linux/security.h> 19 #include <linux/signal.h> 20 #include <linux/uio.h> 21 #include <linux/audit.h> 22 #include <linux/pid_namespace.h> 23 #include <linux/syscalls.h> 24 #include <linux/uaccess.h> 25 #include <linux/regset.h> 26 #include <linux/hw_breakpoint.h> 27 #include <linux/cn_proc.h> 28 #include <linux/compat.h> 29 30 31 /* 32 * ptrace a task: make the debugger its new parent and 33 * move it to the ptrace list. 34 * 35 * Must be called with the tasklist lock write-held. 36 */ 37 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) 38 { 39 BUG_ON(!list_empty(&child->ptrace_entry)); 40 list_add(&child->ptrace_entry, &new_parent->ptraced); 41 child->parent = new_parent; 42 } 43 44 /** 45 * __ptrace_unlink - unlink ptracee and restore its execution state 46 * @child: ptracee to be unlinked 47 * 48 * Remove @child from the ptrace list, move it back to the original parent, 49 * and restore the execution state so that it conforms to the group stop 50 * state. 51 * 52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer 53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between 54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. 55 * If the ptracer is exiting, the ptracee can be in any state. 56 * 57 * After detach, the ptracee should be in a state which conforms to the 58 * group stop. If the group is stopped or in the process of stopping, the 59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken 60 * up from TASK_TRACED. 61 * 62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, 63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar 64 * to but in the opposite direction of what happens while attaching to a 65 * stopped task. However, in this direction, the intermediate RUNNING 66 * state is not hidden even from the current ptracer and if it immediately 67 * re-attaches and performs a WNOHANG wait(2), it may fail. 68 * 69 * CONTEXT: 70 * write_lock_irq(tasklist_lock) 71 */ 72 void __ptrace_unlink(struct task_struct *child) 73 { 74 BUG_ON(!child->ptrace); 75 76 child->ptrace = 0; 77 child->parent = child->real_parent; 78 list_del_init(&child->ptrace_entry); 79 80 spin_lock(&child->sighand->siglock); 81 82 /* 83 * Clear all pending traps and TRAPPING. TRAPPING should be 84 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. 85 */ 86 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); 87 task_clear_jobctl_trapping(child); 88 89 /* 90 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and 91 * @child isn't dead. 92 */ 93 if (!(child->flags & PF_EXITING) && 94 (child->signal->flags & SIGNAL_STOP_STOPPED || 95 child->signal->group_stop_count)) { 96 child->jobctl |= JOBCTL_STOP_PENDING; 97 98 /* 99 * This is only possible if this thread was cloned by the 100 * traced task running in the stopped group, set the signal 101 * for the future reports. 102 * FIXME: we should change ptrace_init_task() to handle this 103 * case. 104 */ 105 if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) 106 child->jobctl |= SIGSTOP; 107 } 108 109 /* 110 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick 111 * @child in the butt. Note that @resume should be used iff @child 112 * is in TASK_TRACED; otherwise, we might unduly disrupt 113 * TASK_KILLABLE sleeps. 114 */ 115 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) 116 ptrace_signal_wake_up(child, true); 117 118 spin_unlock(&child->sighand->siglock); 119 } 120 121 /* Ensure that nothing can wake it up, even SIGKILL */ 122 static bool ptrace_freeze_traced(struct task_struct *task) 123 { 124 bool ret = false; 125 126 /* Lockless, nobody but us can set this flag */ 127 if (task->jobctl & JOBCTL_LISTENING) 128 return ret; 129 130 spin_lock_irq(&task->sighand->siglock); 131 if (task_is_traced(task) && !__fatal_signal_pending(task)) { 132 task->state = __TASK_TRACED; 133 ret = true; 134 } 135 spin_unlock_irq(&task->sighand->siglock); 136 137 return ret; 138 } 139 140 static void ptrace_unfreeze_traced(struct task_struct *task) 141 { 142 if (task->state != __TASK_TRACED) 143 return; 144 145 WARN_ON(!task->ptrace || task->parent != current); 146 147 spin_lock_irq(&task->sighand->siglock); 148 if (__fatal_signal_pending(task)) 149 wake_up_state(task, __TASK_TRACED); 150 else 151 task->state = TASK_TRACED; 152 spin_unlock_irq(&task->sighand->siglock); 153 } 154 155 /** 156 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 157 * @child: ptracee to check for 158 * @ignore_state: don't check whether @child is currently %TASK_TRACED 159 * 160 * Check whether @child is being ptraced by %current and ready for further 161 * ptrace operations. If @ignore_state is %false, @child also should be in 162 * %TASK_TRACED state and on return the child is guaranteed to be traced 163 * and not executing. If @ignore_state is %true, @child can be in any 164 * state. 165 * 166 * CONTEXT: 167 * Grabs and releases tasklist_lock and @child->sighand->siglock. 168 * 169 * RETURNS: 170 * 0 on success, -ESRCH if %child is not ready. 171 */ 172 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 173 { 174 int ret = -ESRCH; 175 176 /* 177 * We take the read lock around doing both checks to close a 178 * possible race where someone else was tracing our child and 179 * detached between these two checks. After this locked check, 180 * we are sure that this is our traced child and that can only 181 * be changed by us so it's not changing right after this. 182 */ 183 read_lock(&tasklist_lock); 184 if (child->ptrace && child->parent == current) { 185 WARN_ON(child->state == __TASK_TRACED); 186 /* 187 * child->sighand can't be NULL, release_task() 188 * does ptrace_unlink() before __exit_signal(). 189 */ 190 if (ignore_state || ptrace_freeze_traced(child)) 191 ret = 0; 192 } 193 read_unlock(&tasklist_lock); 194 195 if (!ret && !ignore_state) { 196 if (!wait_task_inactive(child, __TASK_TRACED)) { 197 /* 198 * This can only happen if may_ptrace_stop() fails and 199 * ptrace_stop() changes ->state back to TASK_RUNNING, 200 * so we should not worry about leaking __TASK_TRACED. 201 */ 202 WARN_ON(child->state == __TASK_TRACED); 203 ret = -ESRCH; 204 } 205 } 206 207 return ret; 208 } 209 210 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 211 { 212 if (mode & PTRACE_MODE_NOAUDIT) 213 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); 214 else 215 return has_ns_capability(current, ns, CAP_SYS_PTRACE); 216 } 217 218 /* Returns 0 on success, -errno on denial. */ 219 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 220 { 221 const struct cred *cred = current_cred(), *tcred; 222 223 /* May we inspect the given task? 224 * This check is used both for attaching with ptrace 225 * and for allowing access to sensitive information in /proc. 226 * 227 * ptrace_attach denies several cases that /proc allows 228 * because setting up the necessary parent/child relationship 229 * or halting the specified task is impossible. 230 */ 231 int dumpable = 0; 232 /* Don't let security modules deny introspection */ 233 if (same_thread_group(task, current)) 234 return 0; 235 rcu_read_lock(); 236 tcred = __task_cred(task); 237 if (uid_eq(cred->uid, tcred->euid) && 238 uid_eq(cred->uid, tcred->suid) && 239 uid_eq(cred->uid, tcred->uid) && 240 gid_eq(cred->gid, tcred->egid) && 241 gid_eq(cred->gid, tcred->sgid) && 242 gid_eq(cred->gid, tcred->gid)) 243 goto ok; 244 if (ptrace_has_cap(tcred->user_ns, mode)) 245 goto ok; 246 rcu_read_unlock(); 247 return -EPERM; 248 ok: 249 rcu_read_unlock(); 250 smp_rmb(); 251 if (task->mm) 252 dumpable = get_dumpable(task->mm); 253 rcu_read_lock(); 254 if (dumpable != SUID_DUMP_USER && 255 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) { 256 rcu_read_unlock(); 257 return -EPERM; 258 } 259 rcu_read_unlock(); 260 261 return security_ptrace_access_check(task, mode); 262 } 263 264 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 265 { 266 int err; 267 task_lock(task); 268 err = __ptrace_may_access(task, mode); 269 task_unlock(task); 270 return !err; 271 } 272 273 static int ptrace_attach(struct task_struct *task, long request, 274 unsigned long addr, 275 unsigned long flags) 276 { 277 bool seize = (request == PTRACE_SEIZE); 278 int retval; 279 280 retval = -EIO; 281 if (seize) { 282 if (addr != 0) 283 goto out; 284 if (flags & ~(unsigned long)PTRACE_O_MASK) 285 goto out; 286 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 287 } else { 288 flags = PT_PTRACED; 289 } 290 291 audit_ptrace(task); 292 293 retval = -EPERM; 294 if (unlikely(task->flags & PF_KTHREAD)) 295 goto out; 296 if (same_thread_group(task, current)) 297 goto out; 298 299 /* 300 * Protect exec's credential calculations against our interference; 301 * SUID, SGID and LSM creds get determined differently 302 * under ptrace. 303 */ 304 retval = -ERESTARTNOINTR; 305 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 306 goto out; 307 308 task_lock(task); 309 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); 310 task_unlock(task); 311 if (retval) 312 goto unlock_creds; 313 314 write_lock_irq(&tasklist_lock); 315 retval = -EPERM; 316 if (unlikely(task->exit_state)) 317 goto unlock_tasklist; 318 if (task->ptrace) 319 goto unlock_tasklist; 320 321 if (seize) 322 flags |= PT_SEIZED; 323 rcu_read_lock(); 324 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE)) 325 flags |= PT_PTRACE_CAP; 326 rcu_read_unlock(); 327 task->ptrace = flags; 328 329 __ptrace_link(task, current); 330 331 /* SEIZE doesn't trap tracee on attach */ 332 if (!seize) 333 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); 334 335 spin_lock(&task->sighand->siglock); 336 337 /* 338 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 339 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 340 * will be cleared if the child completes the transition or any 341 * event which clears the group stop states happens. We'll wait 342 * for the transition to complete before returning from this 343 * function. 344 * 345 * This hides STOPPED -> RUNNING -> TRACED transition from the 346 * attaching thread but a different thread in the same group can 347 * still observe the transient RUNNING state. IOW, if another 348 * thread's WNOHANG wait(2) on the stopped tracee races against 349 * ATTACH, the wait(2) may fail due to the transient RUNNING. 350 * 351 * The following task_is_stopped() test is safe as both transitions 352 * in and out of STOPPED are protected by siglock. 353 */ 354 if (task_is_stopped(task) && 355 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 356 signal_wake_up_state(task, __TASK_STOPPED); 357 358 spin_unlock(&task->sighand->siglock); 359 360 retval = 0; 361 unlock_tasklist: 362 write_unlock_irq(&tasklist_lock); 363 unlock_creds: 364 mutex_unlock(&task->signal->cred_guard_mutex); 365 out: 366 if (!retval) { 367 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, 368 TASK_UNINTERRUPTIBLE); 369 proc_ptrace_connector(task, PTRACE_ATTACH); 370 } 371 372 return retval; 373 } 374 375 /** 376 * ptrace_traceme -- helper for PTRACE_TRACEME 377 * 378 * Performs checks and sets PT_PTRACED. 379 * Should be used by all ptrace implementations for PTRACE_TRACEME. 380 */ 381 static int ptrace_traceme(void) 382 { 383 int ret = -EPERM; 384 385 write_lock_irq(&tasklist_lock); 386 /* Are we already being traced? */ 387 if (!current->ptrace) { 388 ret = security_ptrace_traceme(current->parent); 389 /* 390 * Check PF_EXITING to ensure ->real_parent has not passed 391 * exit_ptrace(). Otherwise we don't report the error but 392 * pretend ->real_parent untraces us right after return. 393 */ 394 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 395 current->ptrace = PT_PTRACED; 396 __ptrace_link(current, current->real_parent); 397 } 398 } 399 write_unlock_irq(&tasklist_lock); 400 401 return ret; 402 } 403 404 /* 405 * Called with irqs disabled, returns true if childs should reap themselves. 406 */ 407 static int ignoring_children(struct sighand_struct *sigh) 408 { 409 int ret; 410 spin_lock(&sigh->siglock); 411 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 412 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 413 spin_unlock(&sigh->siglock); 414 return ret; 415 } 416 417 /* 418 * Called with tasklist_lock held for writing. 419 * Unlink a traced task, and clean it up if it was a traced zombie. 420 * Return true if it needs to be reaped with release_task(). 421 * (We can't call release_task() here because we already hold tasklist_lock.) 422 * 423 * If it's a zombie, our attachedness prevented normal parent notification 424 * or self-reaping. Do notification now if it would have happened earlier. 425 * If it should reap itself, return true. 426 * 427 * If it's our own child, there is no notification to do. But if our normal 428 * children self-reap, then this child was prevented by ptrace and we must 429 * reap it now, in that case we must also wake up sub-threads sleeping in 430 * do_wait(). 431 */ 432 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 433 { 434 bool dead; 435 436 __ptrace_unlink(p); 437 438 if (p->exit_state != EXIT_ZOMBIE) 439 return false; 440 441 dead = !thread_group_leader(p); 442 443 if (!dead && thread_group_empty(p)) { 444 if (!same_thread_group(p->real_parent, tracer)) 445 dead = do_notify_parent(p, p->exit_signal); 446 else if (ignoring_children(tracer->sighand)) { 447 __wake_up_parent(p, tracer); 448 dead = true; 449 } 450 } 451 /* Mark it as in the process of being reaped. */ 452 if (dead) 453 p->exit_state = EXIT_DEAD; 454 return dead; 455 } 456 457 static int ptrace_detach(struct task_struct *child, unsigned int data) 458 { 459 bool dead = false; 460 461 if (!valid_signal(data)) 462 return -EIO; 463 464 /* Architecture-specific hardware disable .. */ 465 ptrace_disable(child); 466 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 467 468 write_lock_irq(&tasklist_lock); 469 /* 470 * This child can be already killed. Make sure de_thread() or 471 * our sub-thread doing do_wait() didn't do release_task() yet. 472 */ 473 if (child->ptrace) { 474 child->exit_code = data; 475 dead = __ptrace_detach(current, child); 476 } 477 write_unlock_irq(&tasklist_lock); 478 479 proc_ptrace_connector(child, PTRACE_DETACH); 480 if (unlikely(dead)) 481 release_task(child); 482 483 return 0; 484 } 485 486 /* 487 * Detach all tasks we were using ptrace on. Called with tasklist held 488 * for writing. 489 */ 490 void exit_ptrace(struct task_struct *tracer, struct list_head *dead) 491 { 492 struct task_struct *p, *n; 493 494 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 495 if (unlikely(p->ptrace & PT_EXITKILL)) 496 send_sig_info(SIGKILL, SEND_SIG_FORCED, p); 497 498 if (__ptrace_detach(tracer, p)) 499 list_add(&p->ptrace_entry, dead); 500 } 501 } 502 503 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 504 { 505 int copied = 0; 506 507 while (len > 0) { 508 char buf[128]; 509 int this_len, retval; 510 511 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 512 retval = access_process_vm(tsk, src, buf, this_len, 0); 513 if (!retval) { 514 if (copied) 515 break; 516 return -EIO; 517 } 518 if (copy_to_user(dst, buf, retval)) 519 return -EFAULT; 520 copied += retval; 521 src += retval; 522 dst += retval; 523 len -= retval; 524 } 525 return copied; 526 } 527 528 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 529 { 530 int copied = 0; 531 532 while (len > 0) { 533 char buf[128]; 534 int this_len, retval; 535 536 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 537 if (copy_from_user(buf, src, this_len)) 538 return -EFAULT; 539 retval = access_process_vm(tsk, dst, buf, this_len, 1); 540 if (!retval) { 541 if (copied) 542 break; 543 return -EIO; 544 } 545 copied += retval; 546 src += retval; 547 dst += retval; 548 len -= retval; 549 } 550 return copied; 551 } 552 553 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 554 { 555 unsigned flags; 556 557 if (data & ~(unsigned long)PTRACE_O_MASK) 558 return -EINVAL; 559 560 /* Avoid intermediate state when all opts are cleared */ 561 flags = child->ptrace; 562 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 563 flags |= (data << PT_OPT_FLAG_SHIFT); 564 child->ptrace = flags; 565 566 return 0; 567 } 568 569 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) 570 { 571 unsigned long flags; 572 int error = -ESRCH; 573 574 if (lock_task_sighand(child, &flags)) { 575 error = -EINVAL; 576 if (likely(child->last_siginfo != NULL)) { 577 *info = *child->last_siginfo; 578 error = 0; 579 } 580 unlock_task_sighand(child, &flags); 581 } 582 return error; 583 } 584 585 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) 586 { 587 unsigned long flags; 588 int error = -ESRCH; 589 590 if (lock_task_sighand(child, &flags)) { 591 error = -EINVAL; 592 if (likely(child->last_siginfo != NULL)) { 593 *child->last_siginfo = *info; 594 error = 0; 595 } 596 unlock_task_sighand(child, &flags); 597 } 598 return error; 599 } 600 601 static int ptrace_peek_siginfo(struct task_struct *child, 602 unsigned long addr, 603 unsigned long data) 604 { 605 struct ptrace_peeksiginfo_args arg; 606 struct sigpending *pending; 607 struct sigqueue *q; 608 int ret, i; 609 610 ret = copy_from_user(&arg, (void __user *) addr, 611 sizeof(struct ptrace_peeksiginfo_args)); 612 if (ret) 613 return -EFAULT; 614 615 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 616 return -EINVAL; /* unknown flags */ 617 618 if (arg.nr < 0) 619 return -EINVAL; 620 621 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 622 pending = &child->signal->shared_pending; 623 else 624 pending = &child->pending; 625 626 for (i = 0; i < arg.nr; ) { 627 siginfo_t info; 628 s32 off = arg.off + i; 629 630 spin_lock_irq(&child->sighand->siglock); 631 list_for_each_entry(q, &pending->list, list) { 632 if (!off--) { 633 copy_siginfo(&info, &q->info); 634 break; 635 } 636 } 637 spin_unlock_irq(&child->sighand->siglock); 638 639 if (off >= 0) /* beyond the end of the list */ 640 break; 641 642 #ifdef CONFIG_COMPAT 643 if (unlikely(is_compat_task())) { 644 compat_siginfo_t __user *uinfo = compat_ptr(data); 645 646 if (copy_siginfo_to_user32(uinfo, &info) || 647 __put_user(info.si_code, &uinfo->si_code)) { 648 ret = -EFAULT; 649 break; 650 } 651 652 } else 653 #endif 654 { 655 siginfo_t __user *uinfo = (siginfo_t __user *) data; 656 657 if (copy_siginfo_to_user(uinfo, &info) || 658 __put_user(info.si_code, &uinfo->si_code)) { 659 ret = -EFAULT; 660 break; 661 } 662 } 663 664 data += sizeof(siginfo_t); 665 i++; 666 667 if (signal_pending(current)) 668 break; 669 670 cond_resched(); 671 } 672 673 if (i > 0) 674 return i; 675 676 return ret; 677 } 678 679 #ifdef PTRACE_SINGLESTEP 680 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 681 #else 682 #define is_singlestep(request) 0 683 #endif 684 685 #ifdef PTRACE_SINGLEBLOCK 686 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 687 #else 688 #define is_singleblock(request) 0 689 #endif 690 691 #ifdef PTRACE_SYSEMU 692 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 693 #else 694 #define is_sysemu_singlestep(request) 0 695 #endif 696 697 static int ptrace_resume(struct task_struct *child, long request, 698 unsigned long data) 699 { 700 if (!valid_signal(data)) 701 return -EIO; 702 703 if (request == PTRACE_SYSCALL) 704 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 705 else 706 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 707 708 #ifdef TIF_SYSCALL_EMU 709 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 710 set_tsk_thread_flag(child, TIF_SYSCALL_EMU); 711 else 712 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 713 #endif 714 715 if (is_singleblock(request)) { 716 if (unlikely(!arch_has_block_step())) 717 return -EIO; 718 user_enable_block_step(child); 719 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 720 if (unlikely(!arch_has_single_step())) 721 return -EIO; 722 user_enable_single_step(child); 723 } else { 724 user_disable_single_step(child); 725 } 726 727 child->exit_code = data; 728 wake_up_state(child, __TASK_TRACED); 729 730 return 0; 731 } 732 733 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 734 735 static const struct user_regset * 736 find_regset(const struct user_regset_view *view, unsigned int type) 737 { 738 const struct user_regset *regset; 739 int n; 740 741 for (n = 0; n < view->n; ++n) { 742 regset = view->regsets + n; 743 if (regset->core_note_type == type) 744 return regset; 745 } 746 747 return NULL; 748 } 749 750 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 751 struct iovec *kiov) 752 { 753 const struct user_regset_view *view = task_user_regset_view(task); 754 const struct user_regset *regset = find_regset(view, type); 755 int regset_no; 756 757 if (!regset || (kiov->iov_len % regset->size) != 0) 758 return -EINVAL; 759 760 regset_no = regset - view->regsets; 761 kiov->iov_len = min(kiov->iov_len, 762 (__kernel_size_t) (regset->n * regset->size)); 763 764 if (req == PTRACE_GETREGSET) 765 return copy_regset_to_user(task, view, regset_no, 0, 766 kiov->iov_len, kiov->iov_base); 767 else 768 return copy_regset_from_user(task, view, regset_no, 0, 769 kiov->iov_len, kiov->iov_base); 770 } 771 772 /* 773 * This is declared in linux/regset.h and defined in machine-dependent 774 * code. We put the export here, near the primary machine-neutral use, 775 * to ensure no machine forgets it. 776 */ 777 EXPORT_SYMBOL_GPL(task_user_regset_view); 778 #endif 779 780 int ptrace_request(struct task_struct *child, long request, 781 unsigned long addr, unsigned long data) 782 { 783 bool seized = child->ptrace & PT_SEIZED; 784 int ret = -EIO; 785 siginfo_t siginfo, *si; 786 void __user *datavp = (void __user *) data; 787 unsigned long __user *datalp = datavp; 788 unsigned long flags; 789 790 switch (request) { 791 case PTRACE_PEEKTEXT: 792 case PTRACE_PEEKDATA: 793 return generic_ptrace_peekdata(child, addr, data); 794 case PTRACE_POKETEXT: 795 case PTRACE_POKEDATA: 796 return generic_ptrace_pokedata(child, addr, data); 797 798 #ifdef PTRACE_OLDSETOPTIONS 799 case PTRACE_OLDSETOPTIONS: 800 #endif 801 case PTRACE_SETOPTIONS: 802 ret = ptrace_setoptions(child, data); 803 break; 804 case PTRACE_GETEVENTMSG: 805 ret = put_user(child->ptrace_message, datalp); 806 break; 807 808 case PTRACE_PEEKSIGINFO: 809 ret = ptrace_peek_siginfo(child, addr, data); 810 break; 811 812 case PTRACE_GETSIGINFO: 813 ret = ptrace_getsiginfo(child, &siginfo); 814 if (!ret) 815 ret = copy_siginfo_to_user(datavp, &siginfo); 816 break; 817 818 case PTRACE_SETSIGINFO: 819 if (copy_from_user(&siginfo, datavp, sizeof siginfo)) 820 ret = -EFAULT; 821 else 822 ret = ptrace_setsiginfo(child, &siginfo); 823 break; 824 825 case PTRACE_GETSIGMASK: 826 if (addr != sizeof(sigset_t)) { 827 ret = -EINVAL; 828 break; 829 } 830 831 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) 832 ret = -EFAULT; 833 else 834 ret = 0; 835 836 break; 837 838 case PTRACE_SETSIGMASK: { 839 sigset_t new_set; 840 841 if (addr != sizeof(sigset_t)) { 842 ret = -EINVAL; 843 break; 844 } 845 846 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 847 ret = -EFAULT; 848 break; 849 } 850 851 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 852 853 /* 854 * Every thread does recalc_sigpending() after resume, so 855 * retarget_shared_pending() and recalc_sigpending() are not 856 * called here. 857 */ 858 spin_lock_irq(&child->sighand->siglock); 859 child->blocked = new_set; 860 spin_unlock_irq(&child->sighand->siglock); 861 862 ret = 0; 863 break; 864 } 865 866 case PTRACE_INTERRUPT: 867 /* 868 * Stop tracee without any side-effect on signal or job 869 * control. At least one trap is guaranteed to happen 870 * after this request. If @child is already trapped, the 871 * current trap is not disturbed and another trap will 872 * happen after the current trap is ended with PTRACE_CONT. 873 * 874 * The actual trap might not be PTRACE_EVENT_STOP trap but 875 * the pending condition is cleared regardless. 876 */ 877 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 878 break; 879 880 /* 881 * INTERRUPT doesn't disturb existing trap sans one 882 * exception. If ptracer issued LISTEN for the current 883 * STOP, this INTERRUPT should clear LISTEN and re-trap 884 * tracee into STOP. 885 */ 886 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 887 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 888 889 unlock_task_sighand(child, &flags); 890 ret = 0; 891 break; 892 893 case PTRACE_LISTEN: 894 /* 895 * Listen for events. Tracee must be in STOP. It's not 896 * resumed per-se but is not considered to be in TRACED by 897 * wait(2) or ptrace(2). If an async event (e.g. group 898 * stop state change) happens, tracee will enter STOP trap 899 * again. Alternatively, ptracer can issue INTERRUPT to 900 * finish listening and re-trap tracee into STOP. 901 */ 902 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 903 break; 904 905 si = child->last_siginfo; 906 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 907 child->jobctl |= JOBCTL_LISTENING; 908 /* 909 * If NOTIFY is set, it means event happened between 910 * start of this trap and now. Trigger re-trap. 911 */ 912 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 913 ptrace_signal_wake_up(child, true); 914 ret = 0; 915 } 916 unlock_task_sighand(child, &flags); 917 break; 918 919 case PTRACE_DETACH: /* detach a process that was attached. */ 920 ret = ptrace_detach(child, data); 921 break; 922 923 #ifdef CONFIG_BINFMT_ELF_FDPIC 924 case PTRACE_GETFDPIC: { 925 struct mm_struct *mm = get_task_mm(child); 926 unsigned long tmp = 0; 927 928 ret = -ESRCH; 929 if (!mm) 930 break; 931 932 switch (addr) { 933 case PTRACE_GETFDPIC_EXEC: 934 tmp = mm->context.exec_fdpic_loadmap; 935 break; 936 case PTRACE_GETFDPIC_INTERP: 937 tmp = mm->context.interp_fdpic_loadmap; 938 break; 939 default: 940 break; 941 } 942 mmput(mm); 943 944 ret = put_user(tmp, datalp); 945 break; 946 } 947 #endif 948 949 #ifdef PTRACE_SINGLESTEP 950 case PTRACE_SINGLESTEP: 951 #endif 952 #ifdef PTRACE_SINGLEBLOCK 953 case PTRACE_SINGLEBLOCK: 954 #endif 955 #ifdef PTRACE_SYSEMU 956 case PTRACE_SYSEMU: 957 case PTRACE_SYSEMU_SINGLESTEP: 958 #endif 959 case PTRACE_SYSCALL: 960 case PTRACE_CONT: 961 return ptrace_resume(child, request, data); 962 963 case PTRACE_KILL: 964 if (child->exit_state) /* already dead */ 965 return 0; 966 return ptrace_resume(child, request, SIGKILL); 967 968 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 969 case PTRACE_GETREGSET: 970 case PTRACE_SETREGSET: { 971 struct iovec kiov; 972 struct iovec __user *uiov = datavp; 973 974 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) 975 return -EFAULT; 976 977 if (__get_user(kiov.iov_base, &uiov->iov_base) || 978 __get_user(kiov.iov_len, &uiov->iov_len)) 979 return -EFAULT; 980 981 ret = ptrace_regset(child, request, addr, &kiov); 982 if (!ret) 983 ret = __put_user(kiov.iov_len, &uiov->iov_len); 984 break; 985 } 986 #endif 987 default: 988 break; 989 } 990 991 return ret; 992 } 993 994 static struct task_struct *ptrace_get_task_struct(pid_t pid) 995 { 996 struct task_struct *child; 997 998 rcu_read_lock(); 999 child = find_task_by_vpid(pid); 1000 if (child) 1001 get_task_struct(child); 1002 rcu_read_unlock(); 1003 1004 if (!child) 1005 return ERR_PTR(-ESRCH); 1006 return child; 1007 } 1008 1009 #ifndef arch_ptrace_attach 1010 #define arch_ptrace_attach(child) do { } while (0) 1011 #endif 1012 1013 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1014 unsigned long, data) 1015 { 1016 struct task_struct *child; 1017 long ret; 1018 1019 if (request == PTRACE_TRACEME) { 1020 ret = ptrace_traceme(); 1021 if (!ret) 1022 arch_ptrace_attach(current); 1023 goto out; 1024 } 1025 1026 child = ptrace_get_task_struct(pid); 1027 if (IS_ERR(child)) { 1028 ret = PTR_ERR(child); 1029 goto out; 1030 } 1031 1032 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1033 ret = ptrace_attach(child, request, addr, data); 1034 /* 1035 * Some architectures need to do book-keeping after 1036 * a ptrace attach. 1037 */ 1038 if (!ret) 1039 arch_ptrace_attach(child); 1040 goto out_put_task_struct; 1041 } 1042 1043 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1044 request == PTRACE_INTERRUPT); 1045 if (ret < 0) 1046 goto out_put_task_struct; 1047 1048 ret = arch_ptrace(child, request, addr, data); 1049 if (ret || request != PTRACE_DETACH) 1050 ptrace_unfreeze_traced(child); 1051 1052 out_put_task_struct: 1053 put_task_struct(child); 1054 out: 1055 return ret; 1056 } 1057 1058 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1059 unsigned long data) 1060 { 1061 unsigned long tmp; 1062 int copied; 1063 1064 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); 1065 if (copied != sizeof(tmp)) 1066 return -EIO; 1067 return put_user(tmp, (unsigned long __user *)data); 1068 } 1069 1070 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1071 unsigned long data) 1072 { 1073 int copied; 1074 1075 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); 1076 return (copied == sizeof(data)) ? 0 : -EIO; 1077 } 1078 1079 #if defined CONFIG_COMPAT 1080 #include <linux/compat.h> 1081 1082 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1083 compat_ulong_t addr, compat_ulong_t data) 1084 { 1085 compat_ulong_t __user *datap = compat_ptr(data); 1086 compat_ulong_t word; 1087 siginfo_t siginfo; 1088 int ret; 1089 1090 switch (request) { 1091 case PTRACE_PEEKTEXT: 1092 case PTRACE_PEEKDATA: 1093 ret = access_process_vm(child, addr, &word, sizeof(word), 0); 1094 if (ret != sizeof(word)) 1095 ret = -EIO; 1096 else 1097 ret = put_user(word, datap); 1098 break; 1099 1100 case PTRACE_POKETEXT: 1101 case PTRACE_POKEDATA: 1102 ret = access_process_vm(child, addr, &data, sizeof(data), 1); 1103 ret = (ret != sizeof(data) ? -EIO : 0); 1104 break; 1105 1106 case PTRACE_GETEVENTMSG: 1107 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1108 break; 1109 1110 case PTRACE_GETSIGINFO: 1111 ret = ptrace_getsiginfo(child, &siginfo); 1112 if (!ret) 1113 ret = copy_siginfo_to_user32( 1114 (struct compat_siginfo __user *) datap, 1115 &siginfo); 1116 break; 1117 1118 case PTRACE_SETSIGINFO: 1119 memset(&siginfo, 0, sizeof siginfo); 1120 if (copy_siginfo_from_user32( 1121 &siginfo, (struct compat_siginfo __user *) datap)) 1122 ret = -EFAULT; 1123 else 1124 ret = ptrace_setsiginfo(child, &siginfo); 1125 break; 1126 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1127 case PTRACE_GETREGSET: 1128 case PTRACE_SETREGSET: 1129 { 1130 struct iovec kiov; 1131 struct compat_iovec __user *uiov = 1132 (struct compat_iovec __user *) datap; 1133 compat_uptr_t ptr; 1134 compat_size_t len; 1135 1136 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) 1137 return -EFAULT; 1138 1139 if (__get_user(ptr, &uiov->iov_base) || 1140 __get_user(len, &uiov->iov_len)) 1141 return -EFAULT; 1142 1143 kiov.iov_base = compat_ptr(ptr); 1144 kiov.iov_len = len; 1145 1146 ret = ptrace_regset(child, request, addr, &kiov); 1147 if (!ret) 1148 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1149 break; 1150 } 1151 #endif 1152 1153 default: 1154 ret = ptrace_request(child, request, addr, data); 1155 } 1156 1157 return ret; 1158 } 1159 1160 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 1161 compat_long_t, addr, compat_long_t, data) 1162 { 1163 struct task_struct *child; 1164 long ret; 1165 1166 if (request == PTRACE_TRACEME) { 1167 ret = ptrace_traceme(); 1168 goto out; 1169 } 1170 1171 child = ptrace_get_task_struct(pid); 1172 if (IS_ERR(child)) { 1173 ret = PTR_ERR(child); 1174 goto out; 1175 } 1176 1177 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1178 ret = ptrace_attach(child, request, addr, data); 1179 /* 1180 * Some architectures need to do book-keeping after 1181 * a ptrace attach. 1182 */ 1183 if (!ret) 1184 arch_ptrace_attach(child); 1185 goto out_put_task_struct; 1186 } 1187 1188 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1189 request == PTRACE_INTERRUPT); 1190 if (!ret) { 1191 ret = compat_arch_ptrace(child, request, addr, data); 1192 if (ret || request != PTRACE_DETACH) 1193 ptrace_unfreeze_traced(child); 1194 } 1195 1196 out_put_task_struct: 1197 put_task_struct(child); 1198 out: 1199 return ret; 1200 } 1201 #endif /* CONFIG_COMPAT */ 1202