if (!dumpable && !capable(CAP_SYS_PTRACE))
return -EPERM;
- return security_ptrace_may_access(task, mode);
+ return security_ptrace_access_check(task, mode);
}
bool ptrace_may_access(struct task_struct *task, unsigned int mode)
int ptrace_attach(struct task_struct *task)
{
int retval;
- unsigned long flags;
audit_ptrace(task);
* interference; SUID, SGID and LSM creds get determined differently
* under ptrace.
*/
- retval = mutex_lock_interruptible(&task->cred_guard_mutex);
- if (retval < 0)
+ retval = -ERESTARTNOINTR;
+ if (mutex_lock_interruptible(&task->cred_guard_mutex))
goto out;
-repeat:
- /*
- * Nasty, nasty.
- *
- * We want to hold both the task-lock and the
- * tasklist_lock for writing at the same time.
- * But that's against the rules (tasklist_lock
- * is taken for reading by interrupts on other
- * cpu's that may have task_lock).
- */
- task_lock(task);
- if (!write_trylock_irqsave(&tasklist_lock, flags)) {
- task_unlock(task);
- do {
- cpu_relax();
- } while (!write_can_lock(&tasklist_lock));
- goto repeat;
- }
+ task_lock(task);
retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
+ task_unlock(task);
if (retval)
- goto bad;
+ goto unlock_creds;
+ write_lock_irq(&tasklist_lock);
retval = -EPERM;
if (unlikely(task->exit_state))
- goto bad;
+ goto unlock_tasklist;
if (task->ptrace)
- goto bad;
+ goto unlock_tasklist;
task->ptrace = PT_PTRACED;
if (capable(CAP_SYS_PTRACE))
send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
retval = 0;
-bad:
- write_unlock_irqrestore(&tasklist_lock, flags);
- task_unlock(task);
+unlock_tasklist:
+ write_unlock_irq(&tasklist_lock);
+unlock_creds:
mutex_unlock(&task->cred_guard_mutex);
out:
return retval;
{
int ret = -EPERM;
- /*
- * Are we already being traced?
- */
-repeat:
- task_lock(current);
+ write_lock_irq(&tasklist_lock);
+ /* Are we already being traced? */
if (!current->ptrace) {
- /*
- * 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
current->ptrace = PT_PTRACED;
__ptrace_link(current, current->real_parent);
}
-
- write_unlock_irqrestore(&tasklist_lock, flags);
}
- task_unlock(current);
+ write_unlock_irq(&tasklist_lock);
+
return ret;
}
* 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.
+ * 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)
{
if (!task_detached(p) && thread_group_empty(p)) {
if (!same_thread_group(p->real_parent, tracer))
do_notify_parent(p, p->exit_signal);
- else if (ignoring_children(tracer->sighand))
+ else if (ignoring_children(tracer->sighand)) {
+ __wake_up_parent(p, tracer);
p->exit_signal = -1;
+ }
}
if (task_detached(p)) {
/* Mark it as in the process of being reaped. */
static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
{
+ unsigned long flags;
int error = -ESRCH;
- read_lock(&tasklist_lock);
- if (likely(child->sighand != NULL)) {
+ if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
- spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
*info = *child->last_siginfo;
error = 0;
}
- spin_unlock_irq(&child->sighand->siglock);
+ unlock_task_sighand(child, &flags);
}
- read_unlock(&tasklist_lock);
return error;
}
static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
{
+ unsigned long flags;
int error = -ESRCH;
- read_lock(&tasklist_lock);
- if (likely(child->sighand != NULL)) {
+ if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
- spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
*child->last_siginfo = *info;
error = 0;
}
- spin_unlock_irq(&child->sighand->siglock);
+ unlock_task_sighand(child, &flags);
}
- read_unlock(&tasklist_lock);
return error;
}
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)
+static struct task_struct *ptrace_get_task_struct(pid_t pid)
{
struct task_struct *child;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
child = find_task_by_vpid(pid);
if (child)
get_task_struct(child);
+ rcu_read_unlock();
- read_unlock(&tasklist_lock);
if (!child)
return ERR_PTR(-ESRCH);
return child;