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