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-rw-r--r--kernel/ptrace.c1452
1 files changed, 1452 insertions, 0 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
new file mode 100644
index 0000000000..443057bee8
--- /dev/null
+++ b/kernel/ptrace.c
@@ -0,0 +1,1452 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/kernel/ptrace.c
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Common interfaces for "ptrace()" which we do not want
+ * to continually duplicate across every architecture.
+ */
+
+#include <linux/capability.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/task.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/ptrace.h>
+#include <linux/security.h>
+#include <linux/signal.h>
+#include <linux/uio.h>
+#include <linux/audit.h>
+#include <linux/pid_namespace.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+#include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/cn_proc.h>
+#include <linux/compat.h>
+#include <linux/sched/signal.h>
+#include <linux/minmax.h>
+#include <linux/syscall_user_dispatch.h>
+
+#include <asm/syscall.h> /* for syscall_get_* */
+
+/*
+ * Access another process' address space via ptrace.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
+ void *buf, int len, unsigned int gup_flags)
+{
+ struct mm_struct *mm;
+ int ret;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ if (!tsk->ptrace ||
+ (current != tsk->parent) ||
+ ((get_dumpable(mm) != SUID_DUMP_USER) &&
+ !ptracer_capable(tsk, mm->user_ns))) {
+ mmput(mm);
+ return 0;
+ }
+
+ ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
+ mmput(mm);
+
+ return ret;
+}
+
+
+void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
+ const struct cred *ptracer_cred)
+{
+ BUG_ON(!list_empty(&child->ptrace_entry));
+ list_add(&child->ptrace_entry, &new_parent->ptraced);
+ child->parent = new_parent;
+ child->ptracer_cred = get_cred(ptracer_cred);
+}
+
+/*
+ * ptrace a task: make the debugger its new parent and
+ * move it to the ptrace list.
+ *
+ * Must be called with the tasklist lock write-held.
+ */
+static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
+{
+ __ptrace_link(child, new_parent, current_cred());
+}
+
+/**
+ * __ptrace_unlink - unlink ptracee and restore its execution state
+ * @child: ptracee to be unlinked
+ *
+ * Remove @child from the ptrace list, move it back to the original parent,
+ * and restore the execution state so that it conforms to the group stop
+ * state.
+ *
+ * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
+ * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
+ * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
+ * If the ptracer is exiting, the ptracee can be in any state.
+ *
+ * After detach, the ptracee should be in a state which conforms to the
+ * group stop. If the group is stopped or in the process of stopping, the
+ * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
+ * up from TASK_TRACED.
+ *
+ * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
+ * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
+ * to but in the opposite direction of what happens while attaching to a
+ * stopped task. However, in this direction, the intermediate RUNNING
+ * state is not hidden even from the current ptracer and if it immediately
+ * re-attaches and performs a WNOHANG wait(2), it may fail.
+ *
+ * CONTEXT:
+ * write_lock_irq(tasklist_lock)
+ */
+void __ptrace_unlink(struct task_struct *child)
+{
+ const struct cred *old_cred;
+ BUG_ON(!child->ptrace);
+
+ clear_task_syscall_work(child, SYSCALL_TRACE);
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+ clear_task_syscall_work(child, SYSCALL_EMU);
+#endif
+
+ child->parent = child->real_parent;
+ list_del_init(&child->ptrace_entry);
+ old_cred = child->ptracer_cred;
+ child->ptracer_cred = NULL;
+ put_cred(old_cred);
+
+ spin_lock(&child->sighand->siglock);
+ child->ptrace = 0;
+ /*
+ * Clear all pending traps and TRAPPING. TRAPPING should be
+ * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
+ */
+ task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
+ task_clear_jobctl_trapping(child);
+
+ /*
+ * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
+ * @child isn't dead.
+ */
+ if (!(child->flags & PF_EXITING) &&
+ (child->signal->flags & SIGNAL_STOP_STOPPED ||
+ child->signal->group_stop_count)) {
+ child->jobctl |= JOBCTL_STOP_PENDING;
+
+ /*
+ * This is only possible if this thread was cloned by the
+ * traced task running in the stopped group, set the signal
+ * for the future reports.
+ * FIXME: we should change ptrace_init_task() to handle this
+ * case.
+ */
+ if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
+ child->jobctl |= SIGSTOP;
+ }
+
+ /*
+ * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
+ * @child in the butt. Note that @resume should be used iff @child
+ * is in TASK_TRACED; otherwise, we might unduly disrupt
+ * TASK_KILLABLE sleeps.
+ */
+ if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
+ ptrace_signal_wake_up(child, true);
+
+ spin_unlock(&child->sighand->siglock);
+}
+
+static bool looks_like_a_spurious_pid(struct task_struct *task)
+{
+ if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
+ return false;
+
+ if (task_pid_vnr(task) == task->ptrace_message)
+ return false;
+ /*
+ * The tracee changed its pid but the PTRACE_EVENT_EXEC event
+ * was not wait()'ed, most probably debugger targets the old
+ * leader which was destroyed in de_thread().
+ */
+ return true;
+}
+
+/*
+ * Ensure that nothing can wake it up, even SIGKILL
+ *
+ * A task is switched to this state while a ptrace operation is in progress;
+ * such that the ptrace operation is uninterruptible.
+ */
+static bool ptrace_freeze_traced(struct task_struct *task)
+{
+ bool ret = false;
+
+ /* Lockless, nobody but us can set this flag */
+ if (task->jobctl & JOBCTL_LISTENING)
+ return ret;
+
+ spin_lock_irq(&task->sighand->siglock);
+ if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
+ !__fatal_signal_pending(task)) {
+ task->jobctl |= JOBCTL_PTRACE_FROZEN;
+ ret = true;
+ }
+ spin_unlock_irq(&task->sighand->siglock);
+
+ return ret;
+}
+
+static void ptrace_unfreeze_traced(struct task_struct *task)
+{
+ unsigned long flags;
+
+ /*
+ * The child may be awake and may have cleared
+ * JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will
+ * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew.
+ */
+ if (lock_task_sighand(task, &flags)) {
+ task->jobctl &= ~JOBCTL_PTRACE_FROZEN;
+ if (__fatal_signal_pending(task)) {
+ task->jobctl &= ~JOBCTL_TRACED;
+ wake_up_state(task, __TASK_TRACED);
+ }
+ unlock_task_sighand(task, &flags);
+ }
+}
+
+/**
+ * ptrace_check_attach - check whether ptracee is ready for ptrace operation
+ * @child: ptracee to check for
+ * @ignore_state: don't check whether @child is currently %TASK_TRACED
+ *
+ * Check whether @child is being ptraced by %current and ready for further
+ * ptrace operations. If @ignore_state is %false, @child also should be in
+ * %TASK_TRACED state and on return the child is guaranteed to be traced
+ * and not executing. If @ignore_state is %true, @child can be in any
+ * state.
+ *
+ * CONTEXT:
+ * Grabs and releases tasklist_lock and @child->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 on success, -ESRCH if %child is not ready.
+ */
+static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
+{
+ int ret = -ESRCH;
+
+ /*
+ * We take the read lock around doing both checks to close a
+ * possible race where someone else was tracing our child and
+ * detached between these two checks. After this locked check,
+ * we are sure that this is our traced child and that can only
+ * be changed by us so it's not changing right after this.
+ */
+ read_lock(&tasklist_lock);
+ if (child->ptrace && child->parent == current) {
+ /*
+ * child->sighand can't be NULL, release_task()
+ * does ptrace_unlink() before __exit_signal().
+ */
+ if (ignore_state || ptrace_freeze_traced(child))
+ ret = 0;
+ }
+ read_unlock(&tasklist_lock);
+
+ if (!ret && !ignore_state &&
+ WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN)))
+ ret = -ESRCH;
+
+ return ret;
+}
+
+static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
+{
+ if (mode & PTRACE_MODE_NOAUDIT)
+ return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
+ return ns_capable(ns, CAP_SYS_PTRACE);
+}
+
+/* Returns 0 on success, -errno on denial. */
+static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+ const struct cred *cred = current_cred(), *tcred;
+ struct mm_struct *mm;
+ kuid_t caller_uid;
+ kgid_t caller_gid;
+
+ if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
+ WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
+ return -EPERM;
+ }
+
+ /* May we inspect the given task?
+ * This check is used both for attaching with ptrace
+ * and for allowing access to sensitive information in /proc.
+ *
+ * ptrace_attach denies several cases that /proc allows
+ * because setting up the necessary parent/child relationship
+ * or halting the specified task is impossible.
+ */
+
+ /* Don't let security modules deny introspection */
+ if (same_thread_group(task, current))
+ return 0;
+ rcu_read_lock();
+ if (mode & PTRACE_MODE_FSCREDS) {
+ caller_uid = cred->fsuid;
+ caller_gid = cred->fsgid;
+ } else {
+ /*
+ * Using the euid would make more sense here, but something
+ * in userland might rely on the old behavior, and this
+ * shouldn't be a security problem since
+ * PTRACE_MODE_REALCREDS implies that the caller explicitly
+ * used a syscall that requests access to another process
+ * (and not a filesystem syscall to procfs).
+ */
+ caller_uid = cred->uid;
+ caller_gid = cred->gid;
+ }
+ tcred = __task_cred(task);
+ if (uid_eq(caller_uid, tcred->euid) &&
+ uid_eq(caller_uid, tcred->suid) &&
+ uid_eq(caller_uid, tcred->uid) &&
+ gid_eq(caller_gid, tcred->egid) &&
+ gid_eq(caller_gid, tcred->sgid) &&
+ gid_eq(caller_gid, tcred->gid))
+ goto ok;
+ if (ptrace_has_cap(tcred->user_ns, mode))
+ goto ok;
+ rcu_read_unlock();
+ return -EPERM;
+ok:
+ rcu_read_unlock();
+ /*
+ * If a task drops privileges and becomes nondumpable (through a syscall
+ * like setresuid()) while we are trying to access it, we must ensure
+ * that the dumpability is read after the credentials; otherwise,
+ * we may be able to attach to a task that we shouldn't be able to
+ * attach to (as if the task had dropped privileges without becoming
+ * nondumpable).
+ * Pairs with a write barrier in commit_creds().
+ */
+ smp_rmb();
+ mm = task->mm;
+ if (mm &&
+ ((get_dumpable(mm) != SUID_DUMP_USER) &&
+ !ptrace_has_cap(mm->user_ns, mode)))
+ return -EPERM;
+
+ return security_ptrace_access_check(task, mode);
+}
+
+bool ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+ int err;
+ task_lock(task);
+ err = __ptrace_may_access(task, mode);
+ task_unlock(task);
+ return !err;
+}
+
+static int check_ptrace_options(unsigned long data)
+{
+ if (data & ~(unsigned long)PTRACE_O_MASK)
+ return -EINVAL;
+
+ if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
+ if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
+ !IS_ENABLED(CONFIG_SECCOMP))
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
+ current->ptrace & PT_SUSPEND_SECCOMP)
+ return -EPERM;
+ }
+ return 0;
+}
+
+static int ptrace_attach(struct task_struct *task, long request,
+ unsigned long addr,
+ unsigned long flags)
+{
+ bool seize = (request == PTRACE_SEIZE);
+ int retval;
+
+ retval = -EIO;
+ if (seize) {
+ if (addr != 0)
+ goto out;
+ /*
+ * This duplicates the check in check_ptrace_options() because
+ * ptrace_attach() and ptrace_setoptions() have historically
+ * used different error codes for unknown ptrace options.
+ */
+ if (flags & ~(unsigned long)PTRACE_O_MASK)
+ goto out;
+ retval = check_ptrace_options(flags);
+ if (retval)
+ return retval;
+ flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
+ } else {
+ flags = PT_PTRACED;
+ }
+
+ audit_ptrace(task);
+
+ retval = -EPERM;
+ if (unlikely(task->flags & PF_KTHREAD))
+ goto out;
+ if (same_thread_group(task, current))
+ goto out;
+
+ /*
+ * Protect exec's credential calculations against our interference;
+ * SUID, SGID and LSM creds get determined differently
+ * under ptrace.
+ */
+ retval = -ERESTARTNOINTR;
+ if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
+ goto out;
+
+ task_lock(task);
+ retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
+ task_unlock(task);
+ if (retval)
+ goto unlock_creds;
+
+ write_lock_irq(&tasklist_lock);
+ retval = -EPERM;
+ if (unlikely(task->exit_state))
+ goto unlock_tasklist;
+ if (task->ptrace)
+ goto unlock_tasklist;
+
+ task->ptrace = flags;
+
+ ptrace_link(task, current);
+
+ /* SEIZE doesn't trap tracee on attach */
+ if (!seize)
+ send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
+
+ spin_lock(&task->sighand->siglock);
+
+ /*
+ * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
+ * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
+ * will be cleared if the child completes the transition or any
+ * event which clears the group stop states happens. We'll wait
+ * for the transition to complete before returning from this
+ * function.
+ *
+ * This hides STOPPED -> RUNNING -> TRACED transition from the
+ * attaching thread but a different thread in the same group can
+ * still observe the transient RUNNING state. IOW, if another
+ * thread's WNOHANG wait(2) on the stopped tracee races against
+ * ATTACH, the wait(2) may fail due to the transient RUNNING.
+ *
+ * The following task_is_stopped() test is safe as both transitions
+ * in and out of STOPPED are protected by siglock.
+ */
+ if (task_is_stopped(task) &&
+ task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
+ task->jobctl &= ~JOBCTL_STOPPED;
+ signal_wake_up_state(task, __TASK_STOPPED);
+ }
+
+ spin_unlock(&task->sighand->siglock);
+
+ retval = 0;
+unlock_tasklist:
+ write_unlock_irq(&tasklist_lock);
+unlock_creds:
+ mutex_unlock(&task->signal->cred_guard_mutex);
+out:
+ if (!retval) {
+ /*
+ * We do not bother to change retval or clear JOBCTL_TRAPPING
+ * if wait_on_bit() was interrupted by SIGKILL. The tracer will
+ * not return to user-mode, it will exit and clear this bit in
+ * __ptrace_unlink() if it wasn't already cleared by the tracee;
+ * and until then nobody can ptrace this task.
+ */
+ wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
+ proc_ptrace_connector(task, PTRACE_ATTACH);
+ }
+
+ return retval;
+}
+
+/**
+ * ptrace_traceme -- helper for PTRACE_TRACEME
+ *
+ * Performs checks and sets PT_PTRACED.
+ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+ */
+static int ptrace_traceme(void)
+{
+ int ret = -EPERM;
+
+ write_lock_irq(&tasklist_lock);
+ /* Are we already being traced? */
+ if (!current->ptrace) {
+ ret = security_ptrace_traceme(current->parent);
+ /*
+ * Check PF_EXITING to ensure ->real_parent has not passed
+ * exit_ptrace(). Otherwise we don't report the error but
+ * pretend ->real_parent untraces us right after return.
+ */
+ if (!ret && !(current->real_parent->flags & PF_EXITING)) {
+ current->ptrace = PT_PTRACED;
+ ptrace_link(current, current->real_parent);
+ }
+ }
+ write_unlock_irq(&tasklist_lock);
+
+ return ret;
+}
+
+/*
+ * Called with irqs disabled, returns true if childs should reap themselves.
+ */
+static int ignoring_children(struct sighand_struct *sigh)
+{
+ int ret;
+ spin_lock(&sigh->siglock);
+ ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
+ (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
+ spin_unlock(&sigh->siglock);
+ return ret;
+}
+
+/*
+ * Called with tasklist_lock held for writing.
+ * Unlink a traced task, and clean it up if it was a traced zombie.
+ * Return true if it needs to be reaped with release_task().
+ * (We can't call release_task() here because we already hold tasklist_lock.)
+ *
+ * If it's a zombie, our attachedness prevented normal parent notification
+ * or self-reaping. Do notification now if it would have happened earlier.
+ * If it should reap itself, return true.
+ *
+ * If it's our own child, there is no notification to do. But if our normal
+ * children self-reap, then this child was prevented by ptrace and we must
+ * reap it now, in that case we must also wake up sub-threads sleeping in
+ * do_wait().
+ */
+static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
+{
+ bool dead;
+
+ __ptrace_unlink(p);
+
+ if (p->exit_state != EXIT_ZOMBIE)
+ return false;
+
+ dead = !thread_group_leader(p);
+
+ if (!dead && thread_group_empty(p)) {
+ if (!same_thread_group(p->real_parent, tracer))
+ dead = do_notify_parent(p, p->exit_signal);
+ else if (ignoring_children(tracer->sighand)) {
+ __wake_up_parent(p, tracer);
+ dead = true;
+ }
+ }
+ /* Mark it as in the process of being reaped. */
+ if (dead)
+ p->exit_state = EXIT_DEAD;
+ return dead;
+}
+
+static int ptrace_detach(struct task_struct *child, unsigned int data)
+{
+ if (!valid_signal(data))
+ return -EIO;
+
+ /* Architecture-specific hardware disable .. */
+ ptrace_disable(child);
+
+ write_lock_irq(&tasklist_lock);
+ /*
+ * We rely on ptrace_freeze_traced(). It can't be killed and
+ * untraced by another thread, it can't be a zombie.
+ */
+ WARN_ON(!child->ptrace || child->exit_state);
+ /*
+ * tasklist_lock avoids the race with wait_task_stopped(), see
+ * the comment in ptrace_resume().
+ */
+ child->exit_code = data;
+ __ptrace_detach(current, child);
+ write_unlock_irq(&tasklist_lock);
+
+ proc_ptrace_connector(child, PTRACE_DETACH);
+
+ return 0;
+}
+
+/*
+ * Detach all tasks we were using ptrace on. Called with tasklist held
+ * for writing.
+ */
+void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
+{
+ struct task_struct *p, *n;
+
+ list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
+ if (unlikely(p->ptrace & PT_EXITKILL))
+ send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
+
+ if (__ptrace_detach(tracer, p))
+ list_add(&p->ptrace_entry, dead);
+ }
+}
+
+int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
+{
+ int copied = 0;
+
+ while (len > 0) {
+ char buf[128];
+ int this_len, retval;
+
+ this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+ retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
+
+ if (!retval) {
+ if (copied)
+ break;
+ return -EIO;
+ }
+ if (copy_to_user(dst, buf, retval))
+ return -EFAULT;
+ copied += retval;
+ src += retval;
+ dst += retval;
+ len -= retval;
+ }
+ return copied;
+}
+
+int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
+{
+ int copied = 0;
+
+ while (len > 0) {
+ char buf[128];
+ int this_len, retval;
+
+ this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+ if (copy_from_user(buf, src, this_len))
+ return -EFAULT;
+ retval = ptrace_access_vm(tsk, dst, buf, this_len,
+ FOLL_FORCE | FOLL_WRITE);
+ if (!retval) {
+ if (copied)
+ break;
+ return -EIO;
+ }
+ copied += retval;
+ src += retval;
+ dst += retval;
+ len -= retval;
+ }
+ return copied;
+}
+
+static int ptrace_setoptions(struct task_struct *child, unsigned long data)
+{
+ unsigned flags;
+ int ret;
+
+ ret = check_ptrace_options(data);
+ if (ret)
+ return ret;
+
+ /* Avoid intermediate state when all opts are cleared */
+ flags = child->ptrace;
+ flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
+ flags |= (data << PT_OPT_FLAG_SHIFT);
+ child->ptrace = flags;
+
+ return 0;
+}
+
+static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
+{
+ unsigned long flags;
+ int error = -ESRCH;
+
+ if (lock_task_sighand(child, &flags)) {
+ error = -EINVAL;
+ if (likely(child->last_siginfo != NULL)) {
+ copy_siginfo(info, child->last_siginfo);
+ error = 0;
+ }
+ unlock_task_sighand(child, &flags);
+ }
+ return error;
+}
+
+static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
+{
+ unsigned long flags;
+ int error = -ESRCH;
+
+ if (lock_task_sighand(child, &flags)) {
+ error = -EINVAL;
+ if (likely(child->last_siginfo != NULL)) {
+ copy_siginfo(child->last_siginfo, info);
+ error = 0;
+ }
+ unlock_task_sighand(child, &flags);
+ }
+ return error;
+}
+
+static int ptrace_peek_siginfo(struct task_struct *child,
+ unsigned long addr,
+ unsigned long data)
+{
+ struct ptrace_peeksiginfo_args arg;
+ struct sigpending *pending;
+ struct sigqueue *q;
+ int ret, i;
+
+ ret = copy_from_user(&arg, (void __user *) addr,
+ sizeof(struct ptrace_peeksiginfo_args));
+ if (ret)
+ return -EFAULT;
+
+ if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
+ return -EINVAL; /* unknown flags */
+
+ if (arg.nr < 0)
+ return -EINVAL;
+
+ /* Ensure arg.off fits in an unsigned long */
+ if (arg.off > ULONG_MAX)
+ return 0;
+
+ if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
+ pending = &child->signal->shared_pending;
+ else
+ pending = &child->pending;
+
+ for (i = 0; i < arg.nr; ) {
+ kernel_siginfo_t info;
+ unsigned long off = arg.off + i;
+ bool found = false;
+
+ spin_lock_irq(&child->sighand->siglock);
+ list_for_each_entry(q, &pending->list, list) {
+ if (!off--) {
+ found = true;
+ copy_siginfo(&info, &q->info);
+ break;
+ }
+ }
+ spin_unlock_irq(&child->sighand->siglock);
+
+ if (!found) /* beyond the end of the list */
+ break;
+
+#ifdef CONFIG_COMPAT
+ if (unlikely(in_compat_syscall())) {
+ compat_siginfo_t __user *uinfo = compat_ptr(data);
+
+ if (copy_siginfo_to_user32(uinfo, &info)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ } else
+#endif
+ {
+ siginfo_t __user *uinfo = (siginfo_t __user *) data;
+
+ if (copy_siginfo_to_user(uinfo, &info)) {
+ ret = -EFAULT;
+ break;
+ }
+ }
+
+ data += sizeof(siginfo_t);
+ i++;
+
+ if (signal_pending(current))
+ break;
+
+ cond_resched();
+ }
+
+ if (i > 0)
+ return i;
+
+ return ret;
+}
+
+#ifdef CONFIG_RSEQ
+static long ptrace_get_rseq_configuration(struct task_struct *task,
+ unsigned long size, void __user *data)
+{
+ struct ptrace_rseq_configuration conf = {
+ .rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
+ .rseq_abi_size = task->rseq_len,
+ .signature = task->rseq_sig,
+ .flags = 0,
+ };
+
+ size = min_t(unsigned long, size, sizeof(conf));
+ if (copy_to_user(data, &conf, size))
+ return -EFAULT;
+ return sizeof(conf);
+}
+#endif
+
+#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
+
+#ifdef PTRACE_SINGLEBLOCK
+#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
+#else
+#define is_singleblock(request) 0
+#endif
+
+#ifdef PTRACE_SYSEMU
+#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
+#else
+#define is_sysemu_singlestep(request) 0
+#endif
+
+static int ptrace_resume(struct task_struct *child, long request,
+ unsigned long data)
+{
+ if (!valid_signal(data))
+ return -EIO;
+
+ if (request == PTRACE_SYSCALL)
+ set_task_syscall_work(child, SYSCALL_TRACE);
+ else
+ clear_task_syscall_work(child, SYSCALL_TRACE);
+
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+ if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+ set_task_syscall_work(child, SYSCALL_EMU);
+ else
+ clear_task_syscall_work(child, SYSCALL_EMU);
+#endif
+
+ if (is_singleblock(request)) {
+ if (unlikely(!arch_has_block_step()))
+ return -EIO;
+ user_enable_block_step(child);
+ } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
+ if (unlikely(!arch_has_single_step()))
+ return -EIO;
+ user_enable_single_step(child);
+ } else {
+ user_disable_single_step(child);
+ }
+
+ /*
+ * Change ->exit_code and ->state under siglock to avoid the race
+ * with wait_task_stopped() in between; a non-zero ->exit_code will
+ * wrongly look like another report from tracee.
+ *
+ * Note that we need siglock even if ->exit_code == data and/or this
+ * status was not reported yet, the new status must not be cleared by
+ * wait_task_stopped() after resume.
+ */
+ spin_lock_irq(&child->sighand->siglock);
+ child->exit_code = data;
+ child->jobctl &= ~JOBCTL_TRACED;
+ wake_up_state(child, __TASK_TRACED);
+ spin_unlock_irq(&child->sighand->siglock);
+
+ return 0;
+}
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+
+static const struct user_regset *
+find_regset(const struct user_regset_view *view, unsigned int type)
+{
+ const struct user_regset *regset;
+ int n;
+
+ for (n = 0; n < view->n; ++n) {
+ regset = view->regsets + n;
+ if (regset->core_note_type == type)
+ return regset;
+ }
+
+ return NULL;
+}
+
+static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
+ struct iovec *kiov)
+{
+ const struct user_regset_view *view = task_user_regset_view(task);
+ const struct user_regset *regset = find_regset(view, type);
+ int regset_no;
+
+ if (!regset || (kiov->iov_len % regset->size) != 0)
+ return -EINVAL;
+
+ regset_no = regset - view->regsets;
+ kiov->iov_len = min(kiov->iov_len,
+ (__kernel_size_t) (regset->n * regset->size));
+
+ if (req == PTRACE_GETREGSET)
+ return copy_regset_to_user(task, view, regset_no, 0,
+ kiov->iov_len, kiov->iov_base);
+ else
+ return copy_regset_from_user(task, view, regset_no, 0,
+ kiov->iov_len, kiov->iov_base);
+}
+
+/*
+ * This is declared in linux/regset.h and defined in machine-dependent
+ * code. We put the export here, near the primary machine-neutral use,
+ * to ensure no machine forgets it.
+ */
+EXPORT_SYMBOL_GPL(task_user_regset_view);
+
+static unsigned long
+ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
+ struct ptrace_syscall_info *info)
+{
+ unsigned long args[ARRAY_SIZE(info->entry.args)];
+ int i;
+
+ info->op = PTRACE_SYSCALL_INFO_ENTRY;
+ info->entry.nr = syscall_get_nr(child, regs);
+ syscall_get_arguments(child, regs, args);
+ for (i = 0; i < ARRAY_SIZE(args); i++)
+ info->entry.args[i] = args[i];
+
+ /* args is the last field in struct ptrace_syscall_info.entry */
+ return offsetofend(struct ptrace_syscall_info, entry.args);
+}
+
+static unsigned long
+ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
+ struct ptrace_syscall_info *info)
+{
+ /*
+ * As struct ptrace_syscall_info.entry is currently a subset
+ * of struct ptrace_syscall_info.seccomp, it makes sense to
+ * initialize that subset using ptrace_get_syscall_info_entry().
+ * This can be reconsidered in the future if these structures
+ * diverge significantly enough.
+ */
+ ptrace_get_syscall_info_entry(child, regs, info);
+ info->op = PTRACE_SYSCALL_INFO_SECCOMP;
+ info->seccomp.ret_data = child->ptrace_message;
+
+ /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
+ return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
+}
+
+static unsigned long
+ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
+ struct ptrace_syscall_info *info)
+{
+ info->op = PTRACE_SYSCALL_INFO_EXIT;
+ info->exit.rval = syscall_get_error(child, regs);
+ info->exit.is_error = !!info->exit.rval;
+ if (!info->exit.is_error)
+ info->exit.rval = syscall_get_return_value(child, regs);
+
+ /* is_error is the last field in struct ptrace_syscall_info.exit */
+ return offsetofend(struct ptrace_syscall_info, exit.is_error);
+}
+
+static int
+ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
+ void __user *datavp)
+{
+ struct pt_regs *regs = task_pt_regs(child);
+ struct ptrace_syscall_info info = {
+ .op = PTRACE_SYSCALL_INFO_NONE,
+ .arch = syscall_get_arch(child),
+ .instruction_pointer = instruction_pointer(regs),
+ .stack_pointer = user_stack_pointer(regs),
+ };
+ unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
+ unsigned long write_size;
+
+ /*
+ * This does not need lock_task_sighand() to access
+ * child->last_siginfo because ptrace_freeze_traced()
+ * called earlier by ptrace_check_attach() ensures that
+ * the tracee cannot go away and clear its last_siginfo.
+ */
+ switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
+ case SIGTRAP | 0x80:
+ switch (child->ptrace_message) {
+ case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+ actual_size = ptrace_get_syscall_info_entry(child, regs,
+ &info);
+ break;
+ case PTRACE_EVENTMSG_SYSCALL_EXIT:
+ actual_size = ptrace_get_syscall_info_exit(child, regs,
+ &info);
+ break;
+ }
+ break;
+ case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
+ actual_size = ptrace_get_syscall_info_seccomp(child, regs,
+ &info);
+ break;
+ }
+
+ write_size = min(actual_size, user_size);
+ return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
+
+int ptrace_request(struct task_struct *child, long request,
+ unsigned long addr, unsigned long data)
+{
+ bool seized = child->ptrace & PT_SEIZED;
+ int ret = -EIO;
+ kernel_siginfo_t siginfo, *si;
+ void __user *datavp = (void __user *) data;
+ unsigned long __user *datalp = datavp;
+ unsigned long flags;
+
+ switch (request) {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ return generic_ptrace_peekdata(child, addr, data);
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ return generic_ptrace_pokedata(child, addr, data);
+
+#ifdef PTRACE_OLDSETOPTIONS
+ case PTRACE_OLDSETOPTIONS:
+#endif
+ case PTRACE_SETOPTIONS:
+ ret = ptrace_setoptions(child, data);
+ break;
+ case PTRACE_GETEVENTMSG:
+ ret = put_user(child->ptrace_message, datalp);
+ break;
+
+ case PTRACE_PEEKSIGINFO:
+ ret = ptrace_peek_siginfo(child, addr, data);
+ break;
+
+ case PTRACE_GETSIGINFO:
+ ret = ptrace_getsiginfo(child, &siginfo);
+ if (!ret)
+ ret = copy_siginfo_to_user(datavp, &siginfo);
+ break;
+
+ case PTRACE_SETSIGINFO:
+ ret = copy_siginfo_from_user(&siginfo, datavp);
+ if (!ret)
+ ret = ptrace_setsiginfo(child, &siginfo);
+ break;
+
+ case PTRACE_GETSIGMASK: {
+ sigset_t *mask;
+
+ if (addr != sizeof(sigset_t)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (test_tsk_restore_sigmask(child))
+ mask = &child->saved_sigmask;
+ else
+ mask = &child->blocked;
+
+ if (copy_to_user(datavp, mask, sizeof(sigset_t)))
+ ret = -EFAULT;
+ else
+ ret = 0;
+
+ break;
+ }
+
+ case PTRACE_SETSIGMASK: {
+ sigset_t new_set;
+
+ if (addr != sizeof(sigset_t)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+ /*
+ * Every thread does recalc_sigpending() after resume, so
+ * retarget_shared_pending() and recalc_sigpending() are not
+ * called here.
+ */
+ spin_lock_irq(&child->sighand->siglock);
+ child->blocked = new_set;
+ spin_unlock_irq(&child->sighand->siglock);
+
+ clear_tsk_restore_sigmask(child);
+
+ ret = 0;
+ break;
+ }
+
+ case PTRACE_INTERRUPT:
+ /*
+ * Stop tracee without any side-effect on signal or job
+ * control. At least one trap is guaranteed to happen
+ * after this request. If @child is already trapped, the
+ * current trap is not disturbed and another trap will
+ * happen after the current trap is ended with PTRACE_CONT.
+ *
+ * The actual trap might not be PTRACE_EVENT_STOP trap but
+ * the pending condition is cleared regardless.
+ */
+ if (unlikely(!seized || !lock_task_sighand(child, &flags)))
+ break;
+
+ /*
+ * INTERRUPT doesn't disturb existing trap sans one
+ * exception. If ptracer issued LISTEN for the current
+ * STOP, this INTERRUPT should clear LISTEN and re-trap
+ * tracee into STOP.
+ */
+ if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
+ ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
+
+ unlock_task_sighand(child, &flags);
+ ret = 0;
+ break;
+
+ case PTRACE_LISTEN:
+ /*
+ * Listen for events. Tracee must be in STOP. It's not
+ * resumed per-se but is not considered to be in TRACED by
+ * wait(2) or ptrace(2). If an async event (e.g. group
+ * stop state change) happens, tracee will enter STOP trap
+ * again. Alternatively, ptracer can issue INTERRUPT to
+ * finish listening and re-trap tracee into STOP.
+ */
+ if (unlikely(!seized || !lock_task_sighand(child, &flags)))
+ break;
+
+ si = child->last_siginfo;
+ if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
+ child->jobctl |= JOBCTL_LISTENING;
+ /*
+ * If NOTIFY is set, it means event happened between
+ * start of this trap and now. Trigger re-trap.
+ */
+ if (child->jobctl & JOBCTL_TRAP_NOTIFY)
+ ptrace_signal_wake_up(child, true);
+ ret = 0;
+ }
+ unlock_task_sighand(child, &flags);
+ break;
+
+ case PTRACE_DETACH: /* detach a process that was attached. */
+ ret = ptrace_detach(child, data);
+ break;
+
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+ case PTRACE_GETFDPIC: {
+ struct mm_struct *mm = get_task_mm(child);
+ unsigned long tmp = 0;
+
+ ret = -ESRCH;
+ if (!mm)
+ break;
+
+ switch (addr) {
+ case PTRACE_GETFDPIC_EXEC:
+ tmp = mm->context.exec_fdpic_loadmap;
+ break;
+ case PTRACE_GETFDPIC_INTERP:
+ tmp = mm->context.interp_fdpic_loadmap;
+ break;
+ default:
+ break;
+ }
+ mmput(mm);
+
+ ret = put_user(tmp, datalp);
+ break;
+ }
+#endif
+
+ case PTRACE_SINGLESTEP:
+#ifdef PTRACE_SINGLEBLOCK
+ case PTRACE_SINGLEBLOCK:
+#endif
+#ifdef PTRACE_SYSEMU
+ case PTRACE_SYSEMU:
+ case PTRACE_SYSEMU_SINGLESTEP:
+#endif
+ case PTRACE_SYSCALL:
+ case PTRACE_CONT:
+ return ptrace_resume(child, request, data);
+
+ case PTRACE_KILL:
+ send_sig_info(SIGKILL, SEND_SIG_NOINFO, child);
+ return 0;
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+ case PTRACE_GETREGSET:
+ case PTRACE_SETREGSET: {
+ struct iovec kiov;
+ struct iovec __user *uiov = datavp;
+
+ if (!access_ok(uiov, sizeof(*uiov)))
+ return -EFAULT;
+
+ if (__get_user(kiov.iov_base, &uiov->iov_base) ||
+ __get_user(kiov.iov_len, &uiov->iov_len))
+ return -EFAULT;
+
+ ret = ptrace_regset(child, request, addr, &kiov);
+ if (!ret)
+ ret = __put_user(kiov.iov_len, &uiov->iov_len);
+ break;
+ }
+
+ case PTRACE_GET_SYSCALL_INFO:
+ ret = ptrace_get_syscall_info(child, addr, datavp);
+ break;
+#endif
+
+ case PTRACE_SECCOMP_GET_FILTER:
+ ret = seccomp_get_filter(child, addr, datavp);
+ break;
+
+ case PTRACE_SECCOMP_GET_METADATA:
+ ret = seccomp_get_metadata(child, addr, datavp);
+ break;
+
+#ifdef CONFIG_RSEQ
+ case PTRACE_GET_RSEQ_CONFIGURATION:
+ ret = ptrace_get_rseq_configuration(child, addr, datavp);
+ break;
+#endif
+
+ case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG:
+ ret = syscall_user_dispatch_set_config(child, addr, datavp);
+ break;
+
+ case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG:
+ ret = syscall_user_dispatch_get_config(child, addr, datavp);
+ break;
+
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
+ unsigned long, data)
+{
+ struct task_struct *child;
+ long ret;
+
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ goto out;
+ }
+
+ child = find_get_task_by_vpid(pid);
+ if (!child) {
+ ret = -ESRCH;
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, addr, data);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL ||
+ request == PTRACE_INTERRUPT);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ ret = arch_ptrace(child, request, addr, data);
+ if (ret || request != PTRACE_DETACH)
+ ptrace_unfreeze_traced(child);
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ return ret;
+}
+
+int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
+ unsigned long data)
+{
+ unsigned long tmp;
+ int copied;
+
+ copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
+ if (copied != sizeof(tmp))
+ return -EIO;
+ return put_user(tmp, (unsigned long __user *)data);
+}
+
+int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
+ unsigned long data)
+{
+ int copied;
+
+ copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
+ FOLL_FORCE | FOLL_WRITE);
+ return (copied == sizeof(data)) ? 0 : -EIO;
+}
+
+#if defined CONFIG_COMPAT
+
+int compat_ptrace_request(struct task_struct *child, compat_long_t request,
+ compat_ulong_t addr, compat_ulong_t data)
+{
+ compat_ulong_t __user *datap = compat_ptr(data);
+ compat_ulong_t word;
+ kernel_siginfo_t siginfo;
+ int ret;
+
+ switch (request) {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ ret = ptrace_access_vm(child, addr, &word, sizeof(word),
+ FOLL_FORCE);
+ if (ret != sizeof(word))
+ ret = -EIO;
+ else
+ ret = put_user(word, datap);
+ break;
+
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ ret = ptrace_access_vm(child, addr, &data, sizeof(data),
+ FOLL_FORCE | FOLL_WRITE);
+ ret = (ret != sizeof(data) ? -EIO : 0);
+ break;
+
+ case PTRACE_GETEVENTMSG:
+ ret = put_user((compat_ulong_t) child->ptrace_message, datap);
+ break;
+
+ case PTRACE_GETSIGINFO:
+ ret = ptrace_getsiginfo(child, &siginfo);
+ if (!ret)
+ ret = copy_siginfo_to_user32(
+ (struct compat_siginfo __user *) datap,
+ &siginfo);
+ break;
+
+ case PTRACE_SETSIGINFO:
+ ret = copy_siginfo_from_user32(
+ &siginfo, (struct compat_siginfo __user *) datap);
+ if (!ret)
+ ret = ptrace_setsiginfo(child, &siginfo);
+ break;
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+ case PTRACE_GETREGSET:
+ case PTRACE_SETREGSET:
+ {
+ struct iovec kiov;
+ struct compat_iovec __user *uiov =
+ (struct compat_iovec __user *) datap;
+ compat_uptr_t ptr;
+ compat_size_t len;
+
+ if (!access_ok(uiov, sizeof(*uiov)))
+ return -EFAULT;
+
+ if (__get_user(ptr, &uiov->iov_base) ||
+ __get_user(len, &uiov->iov_len))
+ return -EFAULT;
+
+ kiov.iov_base = compat_ptr(ptr);
+ kiov.iov_len = len;
+
+ ret = ptrace_regset(child, request, addr, &kiov);
+ if (!ret)
+ ret = __put_user(kiov.iov_len, &uiov->iov_len);
+ break;
+ }
+#endif
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ }
+
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
+ compat_long_t, addr, compat_long_t, data)
+{
+ struct task_struct *child;
+ long ret;
+
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
+ goto out;
+ }
+
+ child = find_get_task_by_vpid(pid);
+ if (!child) {
+ ret = -ESRCH;
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, addr, data);
+ goto out_put_task_struct;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL ||
+ request == PTRACE_INTERRUPT);
+ if (!ret) {
+ ret = compat_arch_ptrace(child, request, addr, data);
+ if (ret || request != PTRACE_DETACH)
+ ptrace_unfreeze_traced(child);
+ }
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ return ret;
+}
+#endif /* CONFIG_COMPAT */