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edaba2c533
Commit 95a3540da9
("ptrace_detach: the wrong
wakeup breaks the ERESTARTxxx logic") removed the "extra"
wake_up_process() from ptrace_detach(), but as Jan pointed out this breaks
the compatibility.
I believe the changelog is right and this wake_up() is wrong in many
ways, but GDB assumes that ptrace(PTRACE_DETACH, child, 0, 0) always
wakes up the tracee.
Despite the fact this breaks SIGNAL_STOP_STOPPED/group_stop_count logic,
and despite the fact this wake_up_process() can break another
assumption: PTRACE_DETACH with SIGSTOP should leave the tracee in
TASK_STOPPED case. Because the untraced child can dequeue SIGSTOP and
call do_signal_stop() before ptrace_detach() calls wake_up_process().
Revert this change for now. We need some fixes even if we we want to keep
the current behaviour, but these fixes are not for 2.6.30.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
816 lines
19 KiB
C
816 lines
19 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/smp_lock.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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/*
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* Initialize a new task whose father had been ptraced.
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*
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* Called from copy_process().
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*/
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void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
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{
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arch_ptrace_fork(child, clone_flags);
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}
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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 the group stop is completed or in progress,
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* this thread was already counted as stopped.
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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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__set_task_state(child, TASK_STOPPED);
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else
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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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arch_ptrace_untrace(child);
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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_may_access(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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int ptrace_attach(struct task_struct *task)
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{
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int retval;
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unsigned long flags;
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audit_ptrace(task);
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retval = -EPERM;
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if (same_thread_group(task, current))
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goto out;
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/* Protect exec's credential calculations against our interference;
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* SUID, SGID and LSM creds get determined differently under ptrace.
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*/
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retval = mutex_lock_interruptible(&task->cred_exec_mutex);
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if (retval < 0)
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goto out;
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retval = -EPERM;
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repeat:
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/*
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* Nasty, nasty.
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*
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* We want to hold both the task-lock and the
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* tasklist_lock for writing at the same time.
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* But that's against the rules (tasklist_lock
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* is taken for reading by interrupts on other
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* cpu's that may have task_lock).
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*/
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task_lock(task);
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if (!write_trylock_irqsave(&tasklist_lock, flags)) {
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task_unlock(task);
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do {
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cpu_relax();
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} while (!write_can_lock(&tasklist_lock));
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goto repeat;
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}
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if (!task->mm)
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goto bad;
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/* the same process cannot be attached many times */
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if (task->ptrace & PT_PTRACED)
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goto bad;
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retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
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if (retval)
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goto bad;
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/* Go */
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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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bad:
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write_unlock_irqrestore(&tasklist_lock, flags);
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task_unlock(task);
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mutex_unlock(&task->cred_exec_mutex);
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out:
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return retval;
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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.
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* But if our normal children self-reap, then this child
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* was prevented by ptrace and we must reap it now.
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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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p->exit_signal = -1;
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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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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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if (!child->exit_state)
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wake_up_process(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.
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*/
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void exit_ptrace(struct task_struct *tracer)
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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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write_lock_irq(&tasklist_lock);
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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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}
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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, 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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int error = -ESRCH;
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read_lock(&tasklist_lock);
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if (likely(child->sighand != NULL)) {
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error = -EINVAL;
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spin_lock_irq(&child->sighand->siglock);
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if (likely(child->last_siginfo != NULL)) {
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*info = *child->last_siginfo;
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error = 0;
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}
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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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return error;
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}
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static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
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{
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int error = -ESRCH;
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read_lock(&tasklist_lock);
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if (likely(child->sighand != NULL)) {
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error = -EINVAL;
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spin_lock_irq(&child->sighand->siglock);
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if (likely(child->last_siginfo != NULL)) {
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*child->last_siginfo = *info;
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error = 0;
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}
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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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return error;
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}
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#ifdef PTRACE_SINGLESTEP
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#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
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#else
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#define is_singlestep(request) 0
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#endif
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#ifdef PTRACE_SINGLEBLOCK
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#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
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#else
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#define is_singleblock(request) 0
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#endif
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#ifdef PTRACE_SYSEMU
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#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
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#else
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#define is_sysemu_singlestep(request) 0
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#endif
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static int ptrace_resume(struct task_struct *child, long request, long data)
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{
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if (!valid_signal(data))
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return -EIO;
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if (request == PTRACE_SYSCALL)
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set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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else
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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#ifdef TIF_SYSCALL_EMU
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if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
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set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
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else
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clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
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#endif
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if (is_singleblock(request)) {
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if (unlikely(!arch_has_block_step()))
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return -EIO;
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user_enable_block_step(child);
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} else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
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if (unlikely(!arch_has_single_step()))
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return -EIO;
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user_enable_single_step(child);
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} else {
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user_disable_single_step(child);
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}
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child->exit_code = data;
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wake_up_process(child);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ptrace_request(struct task_struct *child, long request,
|
|
long addr, long data)
|
|
{
|
|
int ret = -EIO;
|
|
siginfo_t siginfo;
|
|
|
|
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, (unsigned long __user *) data);
|
|
break;
|
|
|
|
case PTRACE_GETSIGINFO:
|
|
ret = ptrace_getsiginfo(child, &siginfo);
|
|
if (!ret)
|
|
ret = copy_siginfo_to_user((siginfo_t __user *) data,
|
|
&siginfo);
|
|
break;
|
|
|
|
case PTRACE_SETSIGINFO:
|
|
if (copy_from_user(&siginfo, (siginfo_t __user *) data,
|
|
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 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);
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* ptrace_traceme -- helper for PTRACE_TRACEME
|
|
*
|
|
* Performs checks and sets PT_PTRACED.
|
|
* Should be used by all ptrace implementations for PTRACE_TRACEME.
|
|
*/
|
|
int ptrace_traceme(void)
|
|
{
|
|
int ret = -EPERM;
|
|
|
|
/*
|
|
* Are we already being traced?
|
|
*/
|
|
repeat:
|
|
task_lock(current);
|
|
if (!(current->ptrace & PT_PTRACED)) {
|
|
/*
|
|
* See ptrace_attach() comments about the locking here.
|
|
*/
|
|
unsigned long flags;
|
|
if (!write_trylock_irqsave(&tasklist_lock, flags)) {
|
|
task_unlock(current);
|
|
do {
|
|
cpu_relax();
|
|
} while (!write_can_lock(&tasklist_lock));
|
|
goto repeat;
|
|
}
|
|
|
|
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_irqrestore(&tasklist_lock, flags);
|
|
}
|
|
task_unlock(current);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* ptrace_get_task_struct -- grab a task struct reference for ptrace
|
|
* @pid: process id to grab a task_struct reference of
|
|
*
|
|
* This function is a helper for ptrace implementations. It checks
|
|
* permissions and then grabs a task struct for use of the actual
|
|
* ptrace implementation.
|
|
*
|
|
* Returns the task_struct for @pid or an ERR_PTR() on failure.
|
|
*/
|
|
struct task_struct *ptrace_get_task_struct(pid_t pid)
|
|
{
|
|
struct task_struct *child;
|
|
|
|
read_lock(&tasklist_lock);
|
|
child = find_task_by_vpid(pid);
|
|
if (child)
|
|
get_task_struct(child);
|
|
|
|
read_unlock(&tasklist_lock);
|
|
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, long, addr, long, data)
|
|
{
|
|
struct task_struct *child;
|
|
long ret;
|
|
|
|
/*
|
|
* This lock_kernel fixes a subtle race with suid exec
|
|
*/
|
|
lock_kernel();
|
|
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:
|
|
unlock_kernel();
|
|
return ret;
|
|
}
|
|
|
|
int generic_ptrace_peekdata(struct task_struct *tsk, long addr, 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, long addr, 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;
|
|
|
|
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;
|
|
|
|
/*
|
|
* This lock_kernel fixes a subtle race with suid exec
|
|
*/
|
|
lock_kernel();
|
|
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:
|
|
unlock_kernel();
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_COMPAT */
|