--- /dev/null
+/*
+ * 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/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>
+
+
+/*
+ * 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.
+ */
+void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
+{
+ BUG_ON(!list_empty(&child->ptrace_entry));
+ list_add(&child->ptrace_entry, &new_parent->ptraced);
+ child->parent = new_parent;
+}
+
+/**
+ * __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)
+{
+ BUG_ON(!child->ptrace);
+
+ child->ptrace = 0;
+ child->parent = child->real_parent;
+ list_del_init(&child->ptrace_entry);
+
+ spin_lock(&child->sighand->siglock);
+
+ /*
+ * 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);
+}
+
+/* Ensure that nothing can wake it up, even SIGKILL */
+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) && !__fatal_signal_pending(task)) {
+ raw_spin_lock_irq(&task->pi_lock);
+ if (task->state & __TASK_TRACED)
+ task->state = __TASK_TRACED;
+ else
+ task->saved_state = __TASK_TRACED;
+ raw_spin_unlock_irq(&task->pi_lock);
+ ret = true;
+ }
+ spin_unlock_irq(&task->sighand->siglock);
+
+ return ret;
+}
+
+static void ptrace_unfreeze_traced(struct task_struct *task)
+{
+ if (task->state != __TASK_TRACED)
+ return;
+
+ WARN_ON(!task->ptrace || task->parent != current);
+
+ spin_lock_irq(&task->sighand->siglock);
+ if (__fatal_signal_pending(task))
+ wake_up_state(task, __TASK_TRACED);
+ else
+ task->state = TASK_TRACED;
+ spin_unlock_irq(&task->sighand->siglock);
+}
+
+/**
+ * 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) {
+ WARN_ON(child->state == __TASK_TRACED);
+ /*
+ * 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) {
+ if (!wait_task_inactive(child, __TASK_TRACED)) {
+ /*
+ * This can only happen if may_ptrace_stop() fails and
+ * ptrace_stop() changes ->state back to TASK_RUNNING,
+ * so we should not worry about leaking __TASK_TRACED.
+ */
+ WARN_ON(child->state == __TASK_TRACED);
+ ret = -ESRCH;
+ }
+ }
+
+ return ret;
+}
+
+static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
+{
+ if (mode & PTRACE_MODE_NOAUDIT)
+ return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
+ else
+ return has_ns_capability(current, 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;
+
+ /* 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.
+ */
+ int dumpable = 0;
+ /* Don't let security modules deny introspection */
+ if (same_thread_group(task, current))
+ return 0;
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if (uid_eq(cred->uid, tcred->euid) &&
+ uid_eq(cred->uid, tcred->suid) &&
+ uid_eq(cred->uid, tcred->uid) &&
+ gid_eq(cred->gid, tcred->egid) &&
+ gid_eq(cred->gid, tcred->sgid) &&
+ gid_eq(cred->gid, tcred->gid))
+ goto ok;
+ if (ptrace_has_cap(tcred->user_ns, mode))
+ goto ok;
+ rcu_read_unlock();
+ return -EPERM;
+ok:
+ rcu_read_unlock();
+ smp_rmb();
+ if (task->mm)
+ dumpable = get_dumpable(task->mm);
+ rcu_read_lock();
+ if (dumpable != SUID_DUMP_USER &&
+ !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
+ rcu_read_unlock();
+ return -EPERM;
+ }
+ rcu_read_unlock();
+
+ 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 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;
+ if (flags & ~(unsigned long)PTRACE_O_MASK)
+ goto out;
+ 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);
+ 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;
+
+ if (seize)
+ flags |= PT_SEIZED;
+ rcu_read_lock();
+ if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
+ flags |= PT_PTRACE_CAP;
+ rcu_read_unlock();
+ task->ptrace = flags;
+
+ __ptrace_link(task, current);
+
+ /* SEIZE doesn't trap tracee on attach */
+ if (!seize)
+ send_sig_info(SIGSTOP, SEND_SIG_FORCED, 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))
+ 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) {
+ wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
+ TASK_UNINTERRUPTIBLE);
+ 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);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+ 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_FORCED, 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 = access_process_vm(tsk, src, buf, this_len, 0);
+ 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 = access_process_vm(tsk, dst, buf, this_len, 1);
+ 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;
+
+ if (data & ~(unsigned long)PTRACE_O_MASK)
+ return -EINVAL;
+
+ /* 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, siginfo_t *info)
+{
+ unsigned long flags;
+ int error = -ESRCH;
+
+ if (lock_task_sighand(child, &flags)) {
+ error = -EINVAL;
+ if (likely(child->last_siginfo != NULL)) {
+ *info = *child->last_siginfo;
+ error = 0;
+ }
+ unlock_task_sighand(child, &flags);
+ }
+ return error;
+}
+
+static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
+{
+ unsigned long flags;
+ int error = -ESRCH;
+
+ if (lock_task_sighand(child, &flags)) {
+ error = -EINVAL;
+ if (likely(child->last_siginfo != NULL)) {
+ *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;
+
+ if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
+ pending = &child->signal->shared_pending;
+ else
+ pending = &child->pending;
+
+ for (i = 0; i < arg.nr; ) {
+ siginfo_t info;
+ s32 off = arg.off + i;
+
+ spin_lock_irq(&child->sighand->siglock);
+ list_for_each_entry(q, &pending->list, list) {
+ if (!off--) {
+ copy_siginfo(&info, &q->info);
+ break;
+ }
+ }
+ spin_unlock_irq(&child->sighand->siglock);
+
+ if (off >= 0) /* beyond the end of the list */
+ break;
+
+#ifdef CONFIG_COMPAT
+ if (unlikely(is_compat_task())) {
+ compat_siginfo_t __user *uinfo = compat_ptr(data);
+
+ if (copy_siginfo_to_user32(uinfo, &info) ||
+ __put_user(info.si_code, &uinfo->si_code)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ } else
+#endif
+ {
+ siginfo_t __user *uinfo = (siginfo_t __user *) data;
+
+ if (copy_siginfo_to_user(uinfo, &info) ||
+ __put_user(info.si_code, &uinfo->si_code)) {
+ ret = -EFAULT;
+ break;
+ }
+ }
+
+ data += sizeof(siginfo_t);
+ i++;
+
+ if (signal_pending(current))
+ break;
+
+ cond_resched();
+ }
+
+ if (i > 0)
+ return i;
+
+ return ret;
+}
+
+#ifdef PTRACE_SINGLESTEP
+#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
+#else
+#define is_singlestep(request) 0
+#endif
+
+#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)
+{
+ bool need_siglock;
+
+ if (!valid_signal(data))
+ return -EIO;
+
+ if (request == PTRACE_SYSCALL)
+ set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ else
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+#ifdef TIF_SYSCALL_EMU
+ if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+ set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+ else
+ clear_tsk_thread_flag(child, TIF_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.
+ *
+ * If data == 0 we do not care if wait_task_stopped() reports the old
+ * status and clears the code too; this can't race with the tracee, it
+ * takes siglock after resume.
+ */
+ need_siglock = data && !thread_group_empty(current);
+ if (need_siglock)
+ spin_lock_irq(&child->sighand->siglock);
+ child->exit_code = data;
+ wake_up_state(child, __TASK_TRACED);
+ if (need_siglock)
+ 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);
+#endif
+
+int ptrace_request(struct task_struct *child, long request,
+ unsigned long addr, unsigned long data)
+{
+ bool seized = child->ptrace & PT_SEIZED;
+ int ret = -EIO;
+ 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:
+ if (copy_from_user(&siginfo, datavp, sizeof siginfo))
+ ret = -EFAULT;
+ else
+ ret = ptrace_setsiginfo(child, &siginfo);
+ break;
+
+ case PTRACE_GETSIGMASK:
+ if (addr != sizeof(sigset_t)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if (copy_to_user(datavp, &child->blocked, 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);
+
+ 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
+
+#ifdef PTRACE_SINGLESTEP
+ case PTRACE_SINGLESTEP:
+#endif
+#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:
+ if (child->exit_state) /* already dead */
+ return 0;
+ return ptrace_resume(child, request, SIGKILL);
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+ case PTRACE_GETREGSET:
+ case PTRACE_SETREGSET: {
+ struct iovec kiov;
+ struct iovec __user *uiov = datavp;
+
+ if (!access_ok(VERIFY_WRITE, 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;
+ }
+#endif
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static struct task_struct *ptrace_get_task_struct(pid_t pid)
+{
+ struct task_struct *child;
+
+ rcu_read_lock();
+ child = find_task_by_vpid(pid);
+ if (child)
+ get_task_struct(child);
+ rcu_read_unlock();
+
+ if (!child)
+ return ERR_PTR(-ESRCH);
+ return child;
+}
+
+#ifndef arch_ptrace_attach
+#define arch_ptrace_attach(child) do { } while (0)
+#endif
+
+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();
+ if (!ret)
+ arch_ptrace_attach(current);
+ goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, addr, data);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
+ 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 = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
+ 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 = access_process_vm(tsk, addr, &data, sizeof(data), 1);
+ 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;
+ siginfo_t siginfo;
+ int ret;
+
+ switch (request) {
+ case PTRACE_PEEKTEXT:
+ case PTRACE_PEEKDATA:
+ ret = access_process_vm(child, addr, &word, sizeof(word), 0);
+ if (ret != sizeof(word))
+ ret = -EIO;
+ else
+ ret = put_user(word, datap);
+ break;
+
+ case PTRACE_POKETEXT:
+ case PTRACE_POKEDATA:
+ ret = access_process_vm(child, addr, &data, sizeof(data), 1);
+ 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:
+ memset(&siginfo, 0, sizeof siginfo);
+ if (copy_siginfo_from_user32(
+ &siginfo, (struct compat_siginfo __user *) datap))
+ ret = -EFAULT;
+ else
+ 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(VERIFY_WRITE, 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 = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
+
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, addr, data);
+ /*
+ * Some architectures need to do book-keeping after
+ * a ptrace attach.
+ */
+ if (!ret)
+ arch_ptrace_attach(child);
+ 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 */
Code Review / kvmfornfv.git / blobdiff