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 static int ptrace_trapping_sleep_fn(void *flags) 32 { 33 schedule(); 34 return 0; 35 } 36 37 /* 38 * ptrace a task: make the debugger its new parent and 39 * move it to the ptrace list. 40 * 41 * Must be called with the tasklist lock write-held. 42 */ 43 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) 44 { 45 BUG_ON(!list_empty(&child->ptrace_entry)); 46 list_add(&child->ptrace_entry, &new_parent->ptraced); 47 child->parent = new_parent; 48 } 49 50 /** 51 * __ptrace_unlink - unlink ptracee and restore its execution state 52 * @child: ptracee to be unlinked 53 * 54 * Remove @child from the ptrace list, move it back to the original parent, 55 * and restore the execution state so that it conforms to the group stop 56 * state. 57 * 58 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer 59 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between 60 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED. 61 * If the ptracer is exiting, the ptracee can be in any state. 62 * 63 * After detach, the ptracee should be in a state which conforms to the 64 * group stop. If the group is stopped or in the process of stopping, the 65 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken 66 * up from TASK_TRACED. 67 * 68 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED, 69 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar 70 * to but in the opposite direction of what happens while attaching to a 71 * stopped task. However, in this direction, the intermediate RUNNING 72 * state is not hidden even from the current ptracer and if it immediately 73 * re-attaches and performs a WNOHANG wait(2), it may fail. 74 * 75 * CONTEXT: 76 * write_lock_irq(tasklist_lock) 77 */ 78 void __ptrace_unlink(struct task_struct *child) 79 { 80 BUG_ON(!child->ptrace); 81 82 child->ptrace = 0; 83 child->parent = child->real_parent; 84 list_del_init(&child->ptrace_entry); 85 86 spin_lock(&child->sighand->siglock); 87 88 /* 89 * Clear all pending traps and TRAPPING. TRAPPING should be 90 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly. 91 */ 92 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK); 93 task_clear_jobctl_trapping(child); 94 95 /* 96 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and 97 * @child isn't dead. 98 */ 99 if (!(child->flags & PF_EXITING) && 100 (child->signal->flags & SIGNAL_STOP_STOPPED || 101 child->signal->group_stop_count)) { 102 child->jobctl |= JOBCTL_STOP_PENDING; 103 104 /* 105 * This is only possible if this thread was cloned by the 106 * traced task running in the stopped group, set the signal 107 * for the future reports. 108 * FIXME: we should change ptrace_init_task() to handle this 109 * case. 110 */ 111 if (!(child->jobctl & JOBCTL_STOP_SIGMASK)) 112 child->jobctl |= SIGSTOP; 113 } 114 115 /* 116 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick 117 * @child in the butt. Note that @resume should be used iff @child 118 * is in TASK_TRACED; otherwise, we might unduly disrupt 119 * TASK_KILLABLE sleeps. 120 */ 121 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child)) 122 ptrace_signal_wake_up(child, true); 123 124 spin_unlock(&child->sighand->siglock); 125 } 126 127 /* Ensure that nothing can wake it up, even SIGKILL */ 128 static bool ptrace_freeze_traced(struct task_struct *task) 129 { 130 bool ret = false; 131 132 /* Lockless, nobody but us can set this flag */ 133 if (task->jobctl & JOBCTL_LISTENING) 134 return ret; 135 136 spin_lock_irq(&task->sighand->siglock); 137 if (task_is_traced(task) && !__fatal_signal_pending(task)) { 138 task->state = __TASK_TRACED; 139 ret = true; 140 } 141 spin_unlock_irq(&task->sighand->siglock); 142 143 return ret; 144 } 145 146 static void ptrace_unfreeze_traced(struct task_struct *task) 147 { 148 if (task->state != __TASK_TRACED) 149 return; 150 151 WARN_ON(!task->ptrace || task->parent != current); 152 153 spin_lock_irq(&task->sighand->siglock); 154 if (__fatal_signal_pending(task)) 155 wake_up_state(task, __TASK_TRACED); 156 else 157 task->state = TASK_TRACED; 158 spin_unlock_irq(&task->sighand->siglock); 159 } 160 161 /** 162 * ptrace_check_attach - check whether ptracee is ready for ptrace operation 163 * @child: ptracee to check for 164 * @ignore_state: don't check whether @child is currently %TASK_TRACED 165 * 166 * Check whether @child is being ptraced by %current and ready for further 167 * ptrace operations. If @ignore_state is %false, @child also should be in 168 * %TASK_TRACED state and on return the child is guaranteed to be traced 169 * and not executing. If @ignore_state is %true, @child can be in any 170 * state. 171 * 172 * CONTEXT: 173 * Grabs and releases tasklist_lock and @child->sighand->siglock. 174 * 175 * RETURNS: 176 * 0 on success, -ESRCH if %child is not ready. 177 */ 178 static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 179 { 180 int ret = -ESRCH; 181 182 /* 183 * We take the read lock around doing both checks to close a 184 * possible race where someone else was tracing our child and 185 * detached between these two checks. After this locked check, 186 * we are sure that this is our traced child and that can only 187 * be changed by us so it's not changing right after this. 188 */ 189 read_lock(&tasklist_lock); 190 if (child->ptrace && child->parent == current) { 191 WARN_ON(child->state == __TASK_TRACED); 192 /* 193 * child->sighand can't be NULL, release_task() 194 * does ptrace_unlink() before __exit_signal(). 195 */ 196 if (ignore_state || ptrace_freeze_traced(child)) 197 ret = 0; 198 } 199 read_unlock(&tasklist_lock); 200 201 if (!ret && !ignore_state) { 202 if (!wait_task_inactive(child, __TASK_TRACED)) { 203 /* 204 * This can only happen if may_ptrace_stop() fails and 205 * ptrace_stop() changes ->state back to TASK_RUNNING, 206 * so we should not worry about leaking __TASK_TRACED. 207 */ 208 WARN_ON(child->state == __TASK_TRACED); 209 ret = -ESRCH; 210 } 211 } 212 213 return ret; 214 } 215 216 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) 217 { 218 if (mode & PTRACE_MODE_NOAUDIT) 219 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); 220 else 221 return has_ns_capability(current, ns, CAP_SYS_PTRACE); 222 } 223 224 /* Returns 0 on success, -errno on denial. */ 225 static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 226 { 227 const struct cred *cred = current_cred(), *tcred; 228 229 /* May we inspect the given task? 230 * This check is used both for attaching with ptrace 231 * and for allowing access to sensitive information in /proc. 232 * 233 * ptrace_attach denies several cases that /proc allows 234 * because setting up the necessary parent/child relationship 235 * or halting the specified task is impossible. 236 */ 237 int dumpable = 0; 238 /* Don't let security modules deny introspection */ 239 if (same_thread_group(task, current)) 240 return 0; 241 rcu_read_lock(); 242 tcred = __task_cred(task); 243 if (uid_eq(cred->uid, tcred->euid) && 244 uid_eq(cred->uid, tcred->suid) && 245 uid_eq(cred->uid, tcred->uid) && 246 gid_eq(cred->gid, tcred->egid) && 247 gid_eq(cred->gid, tcred->sgid) && 248 gid_eq(cred->gid, tcred->gid)) 249 goto ok; 250 if (ptrace_has_cap(tcred->user_ns, mode)) 251 goto ok; 252 rcu_read_unlock(); 253 return -EPERM; 254 ok: 255 rcu_read_unlock(); 256 smp_rmb(); 257 if (task->mm) 258 dumpable = get_dumpable(task->mm); 259 rcu_read_lock(); 260 if (dumpable != SUID_DUMP_USER && 261 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) { 262 rcu_read_unlock(); 263 return -EPERM; 264 } 265 rcu_read_unlock(); 266 267 return security_ptrace_access_check(task, mode); 268 } 269 270 bool ptrace_may_access(struct task_struct *task, unsigned int mode) 271 { 272 int err; 273 task_lock(task); 274 err = __ptrace_may_access(task, mode); 275 task_unlock(task); 276 return !err; 277 } 278 279 static int ptrace_attach(struct task_struct *task, long request, 280 unsigned long addr, 281 unsigned long flags) 282 { 283 bool seize = (request == PTRACE_SEIZE); 284 int retval; 285 286 retval = -EIO; 287 if (seize) { 288 if (addr != 0) 289 goto out; 290 if (flags & ~(unsigned long)PTRACE_O_MASK) 291 goto out; 292 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT); 293 } else { 294 flags = PT_PTRACED; 295 } 296 297 audit_ptrace(task); 298 299 retval = -EPERM; 300 if (unlikely(task->flags & PF_KTHREAD)) 301 goto out; 302 if (same_thread_group(task, current)) 303 goto out; 304 305 /* 306 * Protect exec's credential calculations against our interference; 307 * SUID, SGID and LSM creds get determined differently 308 * under ptrace. 309 */ 310 retval = -ERESTARTNOINTR; 311 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) 312 goto out; 313 314 task_lock(task); 315 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); 316 task_unlock(task); 317 if (retval) 318 goto unlock_creds; 319 320 write_lock_irq(&tasklist_lock); 321 retval = -EPERM; 322 if (unlikely(task->exit_state)) 323 goto unlock_tasklist; 324 if (task->ptrace) 325 goto unlock_tasklist; 326 327 if (seize) 328 flags |= PT_SEIZED; 329 rcu_read_lock(); 330 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE)) 331 flags |= PT_PTRACE_CAP; 332 rcu_read_unlock(); 333 task->ptrace = flags; 334 335 __ptrace_link(task, current); 336 337 /* SEIZE doesn't trap tracee on attach */ 338 if (!seize) 339 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); 340 341 spin_lock(&task->sighand->siglock); 342 343 /* 344 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and 345 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING 346 * will be cleared if the child completes the transition or any 347 * event which clears the group stop states happens. We'll wait 348 * for the transition to complete before returning from this 349 * function. 350 * 351 * This hides STOPPED -> RUNNING -> TRACED transition from the 352 * attaching thread but a different thread in the same group can 353 * still observe the transient RUNNING state. IOW, if another 354 * thread's WNOHANG wait(2) on the stopped tracee races against 355 * ATTACH, the wait(2) may fail due to the transient RUNNING. 356 * 357 * The following task_is_stopped() test is safe as both transitions 358 * in and out of STOPPED are protected by siglock. 359 */ 360 if (task_is_stopped(task) && 361 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) 362 signal_wake_up_state(task, __TASK_STOPPED); 363 364 spin_unlock(&task->sighand->siglock); 365 366 retval = 0; 367 unlock_tasklist: 368 write_unlock_irq(&tasklist_lock); 369 unlock_creds: 370 mutex_unlock(&task->signal->cred_guard_mutex); 371 out: 372 if (!retval) { 373 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, 374 ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); 375 proc_ptrace_connector(task, PTRACE_ATTACH); 376 } 377 378 return retval; 379 } 380 381 /** 382 * ptrace_traceme -- helper for PTRACE_TRACEME 383 * 384 * Performs checks and sets PT_PTRACED. 385 * Should be used by all ptrace implementations for PTRACE_TRACEME. 386 */ 387 static int ptrace_traceme(void) 388 { 389 int ret = -EPERM; 390 391 write_lock_irq(&tasklist_lock); 392 /* Are we already being traced? */ 393 if (!current->ptrace) { 394 ret = security_ptrace_traceme(current->parent); 395 /* 396 * Check PF_EXITING to ensure ->real_parent has not passed 397 * exit_ptrace(). Otherwise we don't report the error but 398 * pretend ->real_parent untraces us right after return. 399 */ 400 if (!ret && !(current->real_parent->flags & PF_EXITING)) { 401 current->ptrace = PT_PTRACED; 402 __ptrace_link(current, current->real_parent); 403 } 404 } 405 write_unlock_irq(&tasklist_lock); 406 407 return ret; 408 } 409 410 /* 411 * Called with irqs disabled, returns true if childs should reap themselves. 412 */ 413 static int ignoring_children(struct sighand_struct *sigh) 414 { 415 int ret; 416 spin_lock(&sigh->siglock); 417 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || 418 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); 419 spin_unlock(&sigh->siglock); 420 return ret; 421 } 422 423 /* 424 * Called with tasklist_lock held for writing. 425 * Unlink a traced task, and clean it up if it was a traced zombie. 426 * Return true if it needs to be reaped with release_task(). 427 * (We can't call release_task() here because we already hold tasklist_lock.) 428 * 429 * If it's a zombie, our attachedness prevented normal parent notification 430 * or self-reaping. Do notification now if it would have happened earlier. 431 * If it should reap itself, return true. 432 * 433 * If it's our own child, there is no notification to do. But if our normal 434 * children self-reap, then this child was prevented by ptrace and we must 435 * reap it now, in that case we must also wake up sub-threads sleeping in 436 * do_wait(). 437 */ 438 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) 439 { 440 bool dead; 441 442 __ptrace_unlink(p); 443 444 if (p->exit_state != EXIT_ZOMBIE) 445 return false; 446 447 dead = !thread_group_leader(p); 448 449 if (!dead && thread_group_empty(p)) { 450 if (!same_thread_group(p->real_parent, tracer)) 451 dead = do_notify_parent(p, p->exit_signal); 452 else if (ignoring_children(tracer->sighand)) { 453 __wake_up_parent(p, tracer); 454 dead = true; 455 } 456 } 457 /* Mark it as in the process of being reaped. */ 458 if (dead) 459 p->exit_state = EXIT_DEAD; 460 return dead; 461 } 462 463 static int ptrace_detach(struct task_struct *child, unsigned int data) 464 { 465 bool dead = false; 466 467 if (!valid_signal(data)) 468 return -EIO; 469 470 /* Architecture-specific hardware disable .. */ 471 ptrace_disable(child); 472 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 473 474 write_lock_irq(&tasklist_lock); 475 /* 476 * This child can be already killed. Make sure de_thread() or 477 * our sub-thread doing do_wait() didn't do release_task() yet. 478 */ 479 if (child->ptrace) { 480 child->exit_code = data; 481 dead = __ptrace_detach(current, child); 482 } 483 write_unlock_irq(&tasklist_lock); 484 485 proc_ptrace_connector(child, PTRACE_DETACH); 486 if (unlikely(dead)) 487 release_task(child); 488 489 return 0; 490 } 491 492 /* 493 * Detach all tasks we were using ptrace on. Called with tasklist held 494 * for writing, and returns with it held too. But note it can release 495 * and reacquire the lock. 496 */ 497 void exit_ptrace(struct task_struct *tracer) 498 __releases(&tasklist_lock) 499 __acquires(&tasklist_lock) 500 { 501 struct task_struct *p, *n; 502 LIST_HEAD(ptrace_dead); 503 504 if (likely(list_empty(&tracer->ptraced))) 505 return; 506 507 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { 508 if (unlikely(p->ptrace & PT_EXITKILL)) 509 send_sig_info(SIGKILL, SEND_SIG_FORCED, p); 510 511 if (__ptrace_detach(tracer, p)) 512 list_add(&p->ptrace_entry, &ptrace_dead); 513 } 514 515 write_unlock_irq(&tasklist_lock); 516 BUG_ON(!list_empty(&tracer->ptraced)); 517 518 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { 519 list_del_init(&p->ptrace_entry); 520 release_task(p); 521 } 522 523 write_lock_irq(&tasklist_lock); 524 } 525 526 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) 527 { 528 int copied = 0; 529 530 while (len > 0) { 531 char buf[128]; 532 int this_len, retval; 533 534 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 535 retval = access_process_vm(tsk, src, buf, this_len, 0); 536 if (!retval) { 537 if (copied) 538 break; 539 return -EIO; 540 } 541 if (copy_to_user(dst, buf, retval)) 542 return -EFAULT; 543 copied += retval; 544 src += retval; 545 dst += retval; 546 len -= retval; 547 } 548 return copied; 549 } 550 551 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) 552 { 553 int copied = 0; 554 555 while (len > 0) { 556 char buf[128]; 557 int this_len, retval; 558 559 this_len = (len > sizeof(buf)) ? sizeof(buf) : len; 560 if (copy_from_user(buf, src, this_len)) 561 return -EFAULT; 562 retval = access_process_vm(tsk, dst, buf, this_len, 1); 563 if (!retval) { 564 if (copied) 565 break; 566 return -EIO; 567 } 568 copied += retval; 569 src += retval; 570 dst += retval; 571 len -= retval; 572 } 573 return copied; 574 } 575 576 static int ptrace_setoptions(struct task_struct *child, unsigned long data) 577 { 578 unsigned flags; 579 580 if (data & ~(unsigned long)PTRACE_O_MASK) 581 return -EINVAL; 582 583 /* Avoid intermediate state when all opts are cleared */ 584 flags = child->ptrace; 585 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); 586 flags |= (data << PT_OPT_FLAG_SHIFT); 587 child->ptrace = flags; 588 589 return 0; 590 } 591 592 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) 593 { 594 unsigned long flags; 595 int error = -ESRCH; 596 597 if (lock_task_sighand(child, &flags)) { 598 error = -EINVAL; 599 if (likely(child->last_siginfo != NULL)) { 600 *info = *child->last_siginfo; 601 error = 0; 602 } 603 unlock_task_sighand(child, &flags); 604 } 605 return error; 606 } 607 608 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) 609 { 610 unsigned long flags; 611 int error = -ESRCH; 612 613 if (lock_task_sighand(child, &flags)) { 614 error = -EINVAL; 615 if (likely(child->last_siginfo != NULL)) { 616 *child->last_siginfo = *info; 617 error = 0; 618 } 619 unlock_task_sighand(child, &flags); 620 } 621 return error; 622 } 623 624 static int ptrace_peek_siginfo(struct task_struct *child, 625 unsigned long addr, 626 unsigned long data) 627 { 628 struct ptrace_peeksiginfo_args arg; 629 struct sigpending *pending; 630 struct sigqueue *q; 631 int ret, i; 632 633 ret = copy_from_user(&arg, (void __user *) addr, 634 sizeof(struct ptrace_peeksiginfo_args)); 635 if (ret) 636 return -EFAULT; 637 638 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED) 639 return -EINVAL; /* unknown flags */ 640 641 if (arg.nr < 0) 642 return -EINVAL; 643 644 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) 645 pending = &child->signal->shared_pending; 646 else 647 pending = &child->pending; 648 649 for (i = 0; i < arg.nr; ) { 650 siginfo_t info; 651 s32 off = arg.off + i; 652 653 spin_lock_irq(&child->sighand->siglock); 654 list_for_each_entry(q, &pending->list, list) { 655 if (!off--) { 656 copy_siginfo(&info, &q->info); 657 break; 658 } 659 } 660 spin_unlock_irq(&child->sighand->siglock); 661 662 if (off >= 0) /* beyond the end of the list */ 663 break; 664 665 #ifdef CONFIG_COMPAT 666 if (unlikely(is_compat_task())) { 667 compat_siginfo_t __user *uinfo = compat_ptr(data); 668 669 if (copy_siginfo_to_user32(uinfo, &info) || 670 __put_user(info.si_code, &uinfo->si_code)) { 671 ret = -EFAULT; 672 break; 673 } 674 675 } else 676 #endif 677 { 678 siginfo_t __user *uinfo = (siginfo_t __user *) data; 679 680 if (copy_siginfo_to_user(uinfo, &info) || 681 __put_user(info.si_code, &uinfo->si_code)) { 682 ret = -EFAULT; 683 break; 684 } 685 } 686 687 data += sizeof(siginfo_t); 688 i++; 689 690 if (signal_pending(current)) 691 break; 692 693 cond_resched(); 694 } 695 696 if (i > 0) 697 return i; 698 699 return ret; 700 } 701 702 #ifdef PTRACE_SINGLESTEP 703 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) 704 #else 705 #define is_singlestep(request) 0 706 #endif 707 708 #ifdef PTRACE_SINGLEBLOCK 709 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) 710 #else 711 #define is_singleblock(request) 0 712 #endif 713 714 #ifdef PTRACE_SYSEMU 715 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) 716 #else 717 #define is_sysemu_singlestep(request) 0 718 #endif 719 720 static int ptrace_resume(struct task_struct *child, long request, 721 unsigned long data) 722 { 723 if (!valid_signal(data)) 724 return -EIO; 725 726 if (request == PTRACE_SYSCALL) 727 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 728 else 729 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 730 731 #ifdef TIF_SYSCALL_EMU 732 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) 733 set_tsk_thread_flag(child, TIF_SYSCALL_EMU); 734 else 735 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); 736 #endif 737 738 if (is_singleblock(request)) { 739 if (unlikely(!arch_has_block_step())) 740 return -EIO; 741 user_enable_block_step(child); 742 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { 743 if (unlikely(!arch_has_single_step())) 744 return -EIO; 745 user_enable_single_step(child); 746 } else { 747 user_disable_single_step(child); 748 } 749 750 child->exit_code = data; 751 wake_up_state(child, __TASK_TRACED); 752 753 return 0; 754 } 755 756 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 757 758 static const struct user_regset * 759 find_regset(const struct user_regset_view *view, unsigned int type) 760 { 761 const struct user_regset *regset; 762 int n; 763 764 for (n = 0; n < view->n; ++n) { 765 regset = view->regsets + n; 766 if (regset->core_note_type == type) 767 return regset; 768 } 769 770 return NULL; 771 } 772 773 static int ptrace_regset(struct task_struct *task, int req, unsigned int type, 774 struct iovec *kiov) 775 { 776 const struct user_regset_view *view = task_user_regset_view(task); 777 const struct user_regset *regset = find_regset(view, type); 778 int regset_no; 779 780 if (!regset || (kiov->iov_len % regset->size) != 0) 781 return -EINVAL; 782 783 regset_no = regset - view->regsets; 784 kiov->iov_len = min(kiov->iov_len, 785 (__kernel_size_t) (regset->n * regset->size)); 786 787 if (req == PTRACE_GETREGSET) 788 return copy_regset_to_user(task, view, regset_no, 0, 789 kiov->iov_len, kiov->iov_base); 790 else 791 return copy_regset_from_user(task, view, regset_no, 0, 792 kiov->iov_len, kiov->iov_base); 793 } 794 795 /* 796 * This is declared in linux/regset.h and defined in machine-dependent 797 * code. We put the export here, near the primary machine-neutral use, 798 * to ensure no machine forgets it. 799 */ 800 EXPORT_SYMBOL_GPL(task_user_regset_view); 801 #endif 802 803 int ptrace_request(struct task_struct *child, long request, 804 unsigned long addr, unsigned long data) 805 { 806 bool seized = child->ptrace & PT_SEIZED; 807 int ret = -EIO; 808 siginfo_t siginfo, *si; 809 void __user *datavp = (void __user *) data; 810 unsigned long __user *datalp = datavp; 811 unsigned long flags; 812 813 switch (request) { 814 case PTRACE_PEEKTEXT: 815 case PTRACE_PEEKDATA: 816 return generic_ptrace_peekdata(child, addr, data); 817 case PTRACE_POKETEXT: 818 case PTRACE_POKEDATA: 819 return generic_ptrace_pokedata(child, addr, data); 820 821 #ifdef PTRACE_OLDSETOPTIONS 822 case PTRACE_OLDSETOPTIONS: 823 #endif 824 case PTRACE_SETOPTIONS: 825 ret = ptrace_setoptions(child, data); 826 break; 827 case PTRACE_GETEVENTMSG: 828 ret = put_user(child->ptrace_message, datalp); 829 break; 830 831 case PTRACE_PEEKSIGINFO: 832 ret = ptrace_peek_siginfo(child, addr, data); 833 break; 834 835 case PTRACE_GETSIGINFO: 836 ret = ptrace_getsiginfo(child, &siginfo); 837 if (!ret) 838 ret = copy_siginfo_to_user(datavp, &siginfo); 839 break; 840 841 case PTRACE_SETSIGINFO: 842 if (copy_from_user(&siginfo, datavp, sizeof siginfo)) 843 ret = -EFAULT; 844 else 845 ret = ptrace_setsiginfo(child, &siginfo); 846 break; 847 848 case PTRACE_GETSIGMASK: 849 if (addr != sizeof(sigset_t)) { 850 ret = -EINVAL; 851 break; 852 } 853 854 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) 855 ret = -EFAULT; 856 else 857 ret = 0; 858 859 break; 860 861 case PTRACE_SETSIGMASK: { 862 sigset_t new_set; 863 864 if (addr != sizeof(sigset_t)) { 865 ret = -EINVAL; 866 break; 867 } 868 869 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) { 870 ret = -EFAULT; 871 break; 872 } 873 874 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); 875 876 /* 877 * Every thread does recalc_sigpending() after resume, so 878 * retarget_shared_pending() and recalc_sigpending() are not 879 * called here. 880 */ 881 spin_lock_irq(&child->sighand->siglock); 882 child->blocked = new_set; 883 spin_unlock_irq(&child->sighand->siglock); 884 885 ret = 0; 886 break; 887 } 888 889 case PTRACE_INTERRUPT: 890 /* 891 * Stop tracee without any side-effect on signal or job 892 * control. At least one trap is guaranteed to happen 893 * after this request. If @child is already trapped, the 894 * current trap is not disturbed and another trap will 895 * happen after the current trap is ended with PTRACE_CONT. 896 * 897 * The actual trap might not be PTRACE_EVENT_STOP trap but 898 * the pending condition is cleared regardless. 899 */ 900 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 901 break; 902 903 /* 904 * INTERRUPT doesn't disturb existing trap sans one 905 * exception. If ptracer issued LISTEN for the current 906 * STOP, this INTERRUPT should clear LISTEN and re-trap 907 * tracee into STOP. 908 */ 909 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP))) 910 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING); 911 912 unlock_task_sighand(child, &flags); 913 ret = 0; 914 break; 915 916 case PTRACE_LISTEN: 917 /* 918 * Listen for events. Tracee must be in STOP. It's not 919 * resumed per-se but is not considered to be in TRACED by 920 * wait(2) or ptrace(2). If an async event (e.g. group 921 * stop state change) happens, tracee will enter STOP trap 922 * again. Alternatively, ptracer can issue INTERRUPT to 923 * finish listening and re-trap tracee into STOP. 924 */ 925 if (unlikely(!seized || !lock_task_sighand(child, &flags))) 926 break; 927 928 si = child->last_siginfo; 929 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) { 930 child->jobctl |= JOBCTL_LISTENING; 931 /* 932 * If NOTIFY is set, it means event happened between 933 * start of this trap and now. Trigger re-trap. 934 */ 935 if (child->jobctl & JOBCTL_TRAP_NOTIFY) 936 ptrace_signal_wake_up(child, true); 937 ret = 0; 938 } 939 unlock_task_sighand(child, &flags); 940 break; 941 942 case PTRACE_DETACH: /* detach a process that was attached. */ 943 ret = ptrace_detach(child, data); 944 break; 945 946 #ifdef CONFIG_BINFMT_ELF_FDPIC 947 case PTRACE_GETFDPIC: { 948 struct mm_struct *mm = get_task_mm(child); 949 unsigned long tmp = 0; 950 951 ret = -ESRCH; 952 if (!mm) 953 break; 954 955 switch (addr) { 956 case PTRACE_GETFDPIC_EXEC: 957 tmp = mm->context.exec_fdpic_loadmap; 958 break; 959 case PTRACE_GETFDPIC_INTERP: 960 tmp = mm->context.interp_fdpic_loadmap; 961 break; 962 default: 963 break; 964 } 965 mmput(mm); 966 967 ret = put_user(tmp, datalp); 968 break; 969 } 970 #endif 971 972 #ifdef PTRACE_SINGLESTEP 973 case PTRACE_SINGLESTEP: 974 #endif 975 #ifdef PTRACE_SINGLEBLOCK 976 case PTRACE_SINGLEBLOCK: 977 #endif 978 #ifdef PTRACE_SYSEMU 979 case PTRACE_SYSEMU: 980 case PTRACE_SYSEMU_SINGLESTEP: 981 #endif 982 case PTRACE_SYSCALL: 983 case PTRACE_CONT: 984 return ptrace_resume(child, request, data); 985 986 case PTRACE_KILL: 987 if (child->exit_state) /* already dead */ 988 return 0; 989 return ptrace_resume(child, request, SIGKILL); 990 991 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 992 case PTRACE_GETREGSET: 993 case PTRACE_SETREGSET: { 994 struct iovec kiov; 995 struct iovec __user *uiov = datavp; 996 997 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) 998 return -EFAULT; 999 1000 if (__get_user(kiov.iov_base, &uiov->iov_base) || 1001 __get_user(kiov.iov_len, &uiov->iov_len)) 1002 return -EFAULT; 1003 1004 ret = ptrace_regset(child, request, addr, &kiov); 1005 if (!ret) 1006 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1007 break; 1008 } 1009 #endif 1010 default: 1011 break; 1012 } 1013 1014 return ret; 1015 } 1016 1017 static struct task_struct *ptrace_get_task_struct(pid_t pid) 1018 { 1019 struct task_struct *child; 1020 1021 rcu_read_lock(); 1022 child = find_task_by_vpid(pid); 1023 if (child) 1024 get_task_struct(child); 1025 rcu_read_unlock(); 1026 1027 if (!child) 1028 return ERR_PTR(-ESRCH); 1029 return child; 1030 } 1031 1032 #ifndef arch_ptrace_attach 1033 #define arch_ptrace_attach(child) do { } while (0) 1034 #endif 1035 1036 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 1037 unsigned long, data) 1038 { 1039 struct task_struct *child; 1040 long ret; 1041 1042 if (request == PTRACE_TRACEME) { 1043 ret = ptrace_traceme(); 1044 if (!ret) 1045 arch_ptrace_attach(current); 1046 goto out; 1047 } 1048 1049 child = ptrace_get_task_struct(pid); 1050 if (IS_ERR(child)) { 1051 ret = PTR_ERR(child); 1052 goto out; 1053 } 1054 1055 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1056 ret = ptrace_attach(child, request, addr, data); 1057 /* 1058 * Some architectures need to do book-keeping after 1059 * a ptrace attach. 1060 */ 1061 if (!ret) 1062 arch_ptrace_attach(child); 1063 goto out_put_task_struct; 1064 } 1065 1066 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1067 request == PTRACE_INTERRUPT); 1068 if (ret < 0) 1069 goto out_put_task_struct; 1070 1071 ret = arch_ptrace(child, request, addr, data); 1072 if (ret || request != PTRACE_DETACH) 1073 ptrace_unfreeze_traced(child); 1074 1075 out_put_task_struct: 1076 put_task_struct(child); 1077 out: 1078 return ret; 1079 } 1080 1081 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 1082 unsigned long data) 1083 { 1084 unsigned long tmp; 1085 int copied; 1086 1087 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); 1088 if (copied != sizeof(tmp)) 1089 return -EIO; 1090 return put_user(tmp, (unsigned long __user *)data); 1091 } 1092 1093 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, 1094 unsigned long data) 1095 { 1096 int copied; 1097 1098 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); 1099 return (copied == sizeof(data)) ? 0 : -EIO; 1100 } 1101 1102 #if defined CONFIG_COMPAT 1103 #include <linux/compat.h> 1104 1105 int compat_ptrace_request(struct task_struct *child, compat_long_t request, 1106 compat_ulong_t addr, compat_ulong_t data) 1107 { 1108 compat_ulong_t __user *datap = compat_ptr(data); 1109 compat_ulong_t word; 1110 siginfo_t siginfo; 1111 int ret; 1112 1113 switch (request) { 1114 case PTRACE_PEEKTEXT: 1115 case PTRACE_PEEKDATA: 1116 ret = access_process_vm(child, addr, &word, sizeof(word), 0); 1117 if (ret != sizeof(word)) 1118 ret = -EIO; 1119 else 1120 ret = put_user(word, datap); 1121 break; 1122 1123 case PTRACE_POKETEXT: 1124 case PTRACE_POKEDATA: 1125 ret = access_process_vm(child, addr, &data, sizeof(data), 1); 1126 ret = (ret != sizeof(data) ? -EIO : 0); 1127 break; 1128 1129 case PTRACE_GETEVENTMSG: 1130 ret = put_user((compat_ulong_t) child->ptrace_message, datap); 1131 break; 1132 1133 case PTRACE_GETSIGINFO: 1134 ret = ptrace_getsiginfo(child, &siginfo); 1135 if (!ret) 1136 ret = copy_siginfo_to_user32( 1137 (struct compat_siginfo __user *) datap, 1138 &siginfo); 1139 break; 1140 1141 case PTRACE_SETSIGINFO: 1142 memset(&siginfo, 0, sizeof siginfo); 1143 if (copy_siginfo_from_user32( 1144 &siginfo, (struct compat_siginfo __user *) datap)) 1145 ret = -EFAULT; 1146 else 1147 ret = ptrace_setsiginfo(child, &siginfo); 1148 break; 1149 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK 1150 case PTRACE_GETREGSET: 1151 case PTRACE_SETREGSET: 1152 { 1153 struct iovec kiov; 1154 struct compat_iovec __user *uiov = 1155 (struct compat_iovec __user *) datap; 1156 compat_uptr_t ptr; 1157 compat_size_t len; 1158 1159 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) 1160 return -EFAULT; 1161 1162 if (__get_user(ptr, &uiov->iov_base) || 1163 __get_user(len, &uiov->iov_len)) 1164 return -EFAULT; 1165 1166 kiov.iov_base = compat_ptr(ptr); 1167 kiov.iov_len = len; 1168 1169 ret = ptrace_regset(child, request, addr, &kiov); 1170 if (!ret) 1171 ret = __put_user(kiov.iov_len, &uiov->iov_len); 1172 break; 1173 } 1174 #endif 1175 1176 default: 1177 ret = ptrace_request(child, request, addr, data); 1178 } 1179 1180 return ret; 1181 } 1182 1183 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, 1184 compat_long_t addr, compat_long_t data) 1185 { 1186 struct task_struct *child; 1187 long ret; 1188 1189 if (request == PTRACE_TRACEME) { 1190 ret = ptrace_traceme(); 1191 goto out; 1192 } 1193 1194 child = ptrace_get_task_struct(pid); 1195 if (IS_ERR(child)) { 1196 ret = PTR_ERR(child); 1197 goto out; 1198 } 1199 1200 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) { 1201 ret = ptrace_attach(child, request, addr, data); 1202 /* 1203 * Some architectures need to do book-keeping after 1204 * a ptrace attach. 1205 */ 1206 if (!ret) 1207 arch_ptrace_attach(child); 1208 goto out_put_task_struct; 1209 } 1210 1211 ret = ptrace_check_attach(child, request == PTRACE_KILL || 1212 request == PTRACE_INTERRUPT); 1213 if (!ret) { 1214 ret = compat_arch_ptrace(child, request, addr, data); 1215 if (ret || request != PTRACE_DETACH) 1216 ptrace_unfreeze_traced(child); 1217 } 1218 1219 out_put_task_struct: 1220 put_task_struct(child); 1221 out: 1222 return ret; 1223 } 1224 #endif /* CONFIG_COMPAT */ 1225