![Tejun Heo](/assets/img/avatar_default.png)
Currently, if the task is STOPPED on ptrace attach, it's left alone and the state is silently changed to TRACED on the next ptrace call. The behavior breaks the assumption that arch_ptrace_stop() is called before any task is poked by ptrace and is ugly in that a task manipulates the state of another task directly. With GROUP_STOP_PENDING, the transitions between TASK_STOPPED and TRACED can be made clean. The tracer can use the flag to tell the tracee to retry stop on attach and detach. On retry, the tracee will enter the desired state in the correct way. The lower 16bits of task->group_stop is used to remember the signal number which caused the last group stop. This is used while retrying for ptrace attach as the original group_exit_code could have been consumed with wait(2) by then. As the real parent may wait(2) and consume the group_exit_code anytime, the group_exit_code needs to be saved separately so that it can be used when switching from regular sleep to ptrace_stop(). This is recorded in the lower 16bits of task->group_stop. If a task is already stopped and there's no intervening SIGCONT, a ptrace request immediately following a successful PTRACE_ATTACH should always succeed even if the tracer doesn't wait(2) for attach completion; however, with this change, the tracee might still be TASK_RUNNING trying to enter TASK_TRACED which would cause the following request to fail with -ESRCH. This intermediate state is hidden from the ptracer by setting GROUP_STOP_TRAPPING on attach and making ptrace_check_attach() wait for it to clear on its signal->wait_chldexit. Completing the transition or getting killed clears TRAPPING and wakes up the tracer. Note that the STOPPED -> RUNNING -> TRACED transition is still visible to other threads which are in the same group as the ptracer and the reverse transition is visible to all. Please read the comments for details. Oleg: * Spotted a race condition where a task may retry group stop without proper bookkeeping. Fixed by redoing bookkeeping on retry. * Spotted that the transition is visible to userland in several different ways. Most are fixed with GROUP_STOP_TRAPPING. Unhandled corner case is documented. * Pointed out not setting GROUP_STOP_SIGMASK on an already stopped task would result in more consistent behavior. * Pointed out that calling ptrace_stop() from do_signal_stop() in TASK_STOPPED can race with group stop start logic and then confuse the TRAPPING wait in ptrace_check_attach(). ptrace_stop() is now called with TASK_RUNNING. * Suggested using signal->wait_chldexit instead of bit wait. * Spotted a race condition between TRACED transition and clearing of TRAPPING. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
916 lines
22 KiB
C
916 lines
22 KiB
C
/*
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* linux/kernel/ptrace.c
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*
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* (C) Copyright 1999 Linus Torvalds
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*
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* Common interfaces for "ptrace()" which we do not want
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* to continually duplicate across every architecture.
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*/
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#include <linux/capability.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/ptrace.h>
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#include <linux/security.h>
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#include <linux/signal.h>
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#include <linux/audit.h>
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#include <linux/pid_namespace.h>
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#include <linux/syscalls.h>
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#include <linux/uaccess.h>
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#include <linux/regset.h>
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/*
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* ptrace a task: make the debugger its new parent and
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* move it to the ptrace list.
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*
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* Must be called with the tasklist lock write-held.
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*/
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void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
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{
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BUG_ON(!list_empty(&child->ptrace_entry));
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list_add(&child->ptrace_entry, &new_parent->ptraced);
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child->parent = new_parent;
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}
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/*
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* Turn a tracing stop into a normal stop now, since with no tracer there
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* would be no way to wake it up with SIGCONT or SIGKILL. If there was a
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* signal sent that would resume the child, but didn't because it was in
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* TASK_TRACED, resume it now.
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* Requires that irqs be disabled.
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*/
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static void ptrace_untrace(struct task_struct *child)
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{
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spin_lock(&child->sighand->siglock);
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if (task_is_traced(child)) {
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/*
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* If group stop is completed or in progress, it should
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* participate in the group stop. Set GROUP_STOP_PENDING
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* before kicking it.
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*
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* This involves TRACED -> RUNNING -> STOPPED transition
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* which is similar to but in the opposite direction of
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* what happens while attaching to a stopped task.
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* However, in this direction, the intermediate RUNNING
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* state is not hidden even from the current ptracer and if
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* it immediately re-attaches and performs a WNOHANG
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* wait(2), it may fail.
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*/
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if (child->signal->flags & SIGNAL_STOP_STOPPED ||
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child->signal->group_stop_count)
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child->group_stop |= GROUP_STOP_PENDING;
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signal_wake_up(child, 1);
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}
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spin_unlock(&child->sighand->siglock);
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}
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/*
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* unptrace a task: move it back to its original parent and
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* remove it from the ptrace list.
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*
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* Must be called with the tasklist lock write-held.
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*/
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void __ptrace_unlink(struct task_struct *child)
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{
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BUG_ON(!child->ptrace);
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child->ptrace = 0;
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child->parent = child->real_parent;
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list_del_init(&child->ptrace_entry);
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if (task_is_traced(child))
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ptrace_untrace(child);
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}
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/*
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* Check that we have indeed attached to the thing..
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*/
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int ptrace_check_attach(struct task_struct *child, int kill)
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{
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int ret = -ESRCH;
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/*
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* We take the read lock around doing both checks to close a
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* possible race where someone else was tracing our child and
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* detached between these two checks. After this locked check,
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* we are sure that this is our traced child and that can only
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* be changed by us so it's not changing right after this.
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*/
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read_lock(&tasklist_lock);
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if ((child->ptrace & PT_PTRACED) && child->parent == current) {
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ret = 0;
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/*
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* child->sighand can't be NULL, release_task()
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* does ptrace_unlink() before __exit_signal().
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*/
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spin_lock_irq(&child->sighand->siglock);
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if (task_is_stopped(child))
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child->state = TASK_TRACED;
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else if (!task_is_traced(child) && !kill)
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ret = -ESRCH;
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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if (!ret && !kill)
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ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
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/* All systems go.. */
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return ret;
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}
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int __ptrace_may_access(struct task_struct *task, unsigned int mode)
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{
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const struct cred *cred = current_cred(), *tcred;
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/* May we inspect the given task?
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* This check is used both for attaching with ptrace
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* and for allowing access to sensitive information in /proc.
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*
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* ptrace_attach denies several cases that /proc allows
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* because setting up the necessary parent/child relationship
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* or halting the specified task is impossible.
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*/
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int dumpable = 0;
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/* Don't let security modules deny introspection */
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if (task == current)
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return 0;
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rcu_read_lock();
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tcred = __task_cred(task);
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if ((cred->uid != tcred->euid ||
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cred->uid != tcred->suid ||
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cred->uid != tcred->uid ||
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cred->gid != tcred->egid ||
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cred->gid != tcred->sgid ||
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cred->gid != tcred->gid) &&
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!capable(CAP_SYS_PTRACE)) {
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rcu_read_unlock();
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return -EPERM;
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}
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rcu_read_unlock();
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smp_rmb();
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if (task->mm)
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dumpable = get_dumpable(task->mm);
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if (!dumpable && !capable(CAP_SYS_PTRACE))
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return -EPERM;
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return security_ptrace_access_check(task, mode);
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}
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bool ptrace_may_access(struct task_struct *task, unsigned int mode)
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{
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int err;
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task_lock(task);
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err = __ptrace_may_access(task, mode);
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task_unlock(task);
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return !err;
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}
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static int ptrace_attach(struct task_struct *task)
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{
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bool wait_trap = false;
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int retval;
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audit_ptrace(task);
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retval = -EPERM;
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if (unlikely(task->flags & PF_KTHREAD))
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goto out;
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if (same_thread_group(task, current))
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goto out;
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/*
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* Protect exec's credential calculations against our interference;
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* interference; SUID, SGID and LSM creds get determined differently
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* under ptrace.
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*/
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retval = -ERESTARTNOINTR;
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if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
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goto out;
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task_lock(task);
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retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
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task_unlock(task);
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if (retval)
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goto unlock_creds;
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write_lock_irq(&tasklist_lock);
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retval = -EPERM;
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if (unlikely(task->exit_state))
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goto unlock_tasklist;
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if (task->ptrace)
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goto unlock_tasklist;
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task->ptrace = PT_PTRACED;
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if (capable(CAP_SYS_PTRACE))
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task->ptrace |= PT_PTRACE_CAP;
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__ptrace_link(task, current);
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send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
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spin_lock(&task->sighand->siglock);
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/*
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* If the task is already STOPPED, set GROUP_STOP_PENDING and
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* TRAPPING, and kick it so that it transits to TRACED. TRAPPING
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* will be cleared if the child completes the transition or any
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* event which clears the group stop states happens. We'll wait
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* for the transition to complete before returning from this
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* function.
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*
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* This hides STOPPED -> RUNNING -> TRACED transition from the
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* attaching thread but a different thread in the same group can
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* still observe the transient RUNNING state. IOW, if another
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* thread's WNOHANG wait(2) on the stopped tracee races against
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* ATTACH, the wait(2) may fail due to the transient RUNNING.
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*
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* The following task_is_stopped() test is safe as both transitions
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* in and out of STOPPED are protected by siglock.
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*/
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if (task_is_stopped(task)) {
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task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
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signal_wake_up(task, 1);
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wait_trap = true;
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}
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spin_unlock(&task->sighand->siglock);
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retval = 0;
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unlock_tasklist:
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write_unlock_irq(&tasklist_lock);
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unlock_creds:
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mutex_unlock(&task->signal->cred_guard_mutex);
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out:
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if (wait_trap)
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wait_event(current->signal->wait_chldexit,
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!(task->group_stop & GROUP_STOP_TRAPPING));
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return retval;
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}
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/**
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* ptrace_traceme -- helper for PTRACE_TRACEME
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*
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* Performs checks and sets PT_PTRACED.
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* Should be used by all ptrace implementations for PTRACE_TRACEME.
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*/
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static int ptrace_traceme(void)
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{
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int ret = -EPERM;
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write_lock_irq(&tasklist_lock);
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/* Are we already being traced? */
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if (!current->ptrace) {
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ret = security_ptrace_traceme(current->parent);
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/*
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* Check PF_EXITING to ensure ->real_parent has not passed
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* exit_ptrace(). Otherwise we don't report the error but
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* pretend ->real_parent untraces us right after return.
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*/
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if (!ret && !(current->real_parent->flags & PF_EXITING)) {
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current->ptrace = PT_PTRACED;
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__ptrace_link(current, current->real_parent);
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}
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}
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write_unlock_irq(&tasklist_lock);
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return ret;
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}
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/*
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* Called with irqs disabled, returns true if childs should reap themselves.
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*/
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static int ignoring_children(struct sighand_struct *sigh)
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{
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int ret;
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spin_lock(&sigh->siglock);
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ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
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(sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
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spin_unlock(&sigh->siglock);
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return ret;
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}
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/*
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* Called with tasklist_lock held for writing.
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* Unlink a traced task, and clean it up if it was a traced zombie.
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* Return true if it needs to be reaped with release_task().
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* (We can't call release_task() here because we already hold tasklist_lock.)
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*
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* If it's a zombie, our attachedness prevented normal parent notification
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* or self-reaping. Do notification now if it would have happened earlier.
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* If it should reap itself, return true.
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*
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* If it's our own child, there is no notification to do. But if our normal
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* children self-reap, then this child was prevented by ptrace and we must
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* reap it now, in that case we must also wake up sub-threads sleeping in
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* do_wait().
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*/
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static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
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{
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__ptrace_unlink(p);
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if (p->exit_state == EXIT_ZOMBIE) {
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if (!task_detached(p) && thread_group_empty(p)) {
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if (!same_thread_group(p->real_parent, tracer))
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do_notify_parent(p, p->exit_signal);
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else if (ignoring_children(tracer->sighand)) {
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__wake_up_parent(p, tracer);
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p->exit_signal = -1;
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}
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}
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if (task_detached(p)) {
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/* Mark it as in the process of being reaped. */
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p->exit_state = EXIT_DEAD;
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return true;
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}
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}
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return false;
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}
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static int ptrace_detach(struct task_struct *child, unsigned int data)
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{
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bool dead = false;
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if (!valid_signal(data))
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return -EIO;
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/* Architecture-specific hardware disable .. */
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ptrace_disable(child);
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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write_lock_irq(&tasklist_lock);
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/*
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* This child can be already killed. Make sure de_thread() or
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* our sub-thread doing do_wait() didn't do release_task() yet.
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*/
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if (child->ptrace) {
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child->exit_code = data;
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dead = __ptrace_detach(current, child);
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}
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write_unlock_irq(&tasklist_lock);
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if (unlikely(dead))
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release_task(child);
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return 0;
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}
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/*
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* Detach all tasks we were using ptrace on. Called with tasklist held
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* for writing, and returns with it held too. But note it can release
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* and reacquire the lock.
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*/
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void exit_ptrace(struct task_struct *tracer)
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__releases(&tasklist_lock)
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__acquires(&tasklist_lock)
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{
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struct task_struct *p, *n;
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LIST_HEAD(ptrace_dead);
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if (likely(list_empty(&tracer->ptraced)))
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return;
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list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
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if (__ptrace_detach(tracer, p))
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list_add(&p->ptrace_entry, &ptrace_dead);
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}
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write_unlock_irq(&tasklist_lock);
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BUG_ON(!list_empty(&tracer->ptraced));
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list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
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list_del_init(&p->ptrace_entry);
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release_task(p);
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}
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write_lock_irq(&tasklist_lock);
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}
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int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
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{
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int copied = 0;
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while (len > 0) {
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char buf[128];
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int this_len, retval;
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this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
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retval = access_process_vm(tsk, src, buf, this_len, 0);
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if (!retval) {
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if (copied)
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break;
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return -EIO;
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}
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if (copy_to_user(dst, buf, retval))
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return -EFAULT;
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copied += retval;
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src += retval;
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dst += retval;
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len -= retval;
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}
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return copied;
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}
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int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
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{
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int copied = 0;
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while (len > 0) {
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char buf[128];
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int this_len, retval;
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this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
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if (copy_from_user(buf, src, this_len))
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return -EFAULT;
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retval = access_process_vm(tsk, dst, buf, this_len, 1);
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if (!retval) {
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if (copied)
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break;
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return -EIO;
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}
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copied += retval;
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src += retval;
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dst += retval;
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len -= retval;
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}
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return copied;
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}
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static int ptrace_setoptions(struct task_struct *child, unsigned long data)
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{
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child->ptrace &= ~PT_TRACE_MASK;
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if (data & PTRACE_O_TRACESYSGOOD)
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child->ptrace |= PT_TRACESYSGOOD;
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if (data & PTRACE_O_TRACEFORK)
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child->ptrace |= PT_TRACE_FORK;
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if (data & PTRACE_O_TRACEVFORK)
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child->ptrace |= PT_TRACE_VFORK;
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if (data & PTRACE_O_TRACECLONE)
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child->ptrace |= PT_TRACE_CLONE;
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if (data & PTRACE_O_TRACEEXEC)
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child->ptrace |= PT_TRACE_EXEC;
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if (data & PTRACE_O_TRACEVFORKDONE)
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child->ptrace |= PT_TRACE_VFORK_DONE;
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if (data & PTRACE_O_TRACEEXIT)
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child->ptrace |= PT_TRACE_EXIT;
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return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
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}
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static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
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{
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unsigned long flags;
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int error = -ESRCH;
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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;
|
|
}
|
|
|
|
|
|
#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)
|
|
{
|
|
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);
|
|
}
|
|
|
|
child->exit_code = data;
|
|
wake_up_process(child);
|
|
|
|
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);
|
|
}
|
|
|
|
#endif
|
|
|
|
int ptrace_request(struct task_struct *child, long request,
|
|
unsigned long addr, unsigned long data)
|
|
{
|
|
int ret = -EIO;
|
|
siginfo_t siginfo;
|
|
void __user *datavp = (void __user *) data;
|
|
unsigned long __user *datalp = datavp;
|
|
|
|
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_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_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) {
|
|
ret = ptrace_attach(child);
|
|
/*
|
|
* 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);
|
|
if (ret < 0)
|
|
goto out_put_task_struct;
|
|
|
|
ret = arch_ptrace(child, request, addr, data);
|
|
|
|
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
|
|
#include <linux/compat.h>
|
|
|
|
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;
|
|
}
|
|
|
|
asmlinkage long compat_sys_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) {
|
|
ret = ptrace_attach(child);
|
|
/*
|
|
* 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);
|
|
if (!ret)
|
|
ret = compat_arch_ptrace(child, request, addr, data);
|
|
|
|
out_put_task_struct:
|
|
put_task_struct(child);
|
|
out:
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_COMPAT */
|