*/
int dumpable = 0;
/* Don't let security modules deny introspection */
- if (task == current)
+ if (same_thread_group(task, current))
return 0;
rcu_read_lock();
tcred = __task_cred(task);
smp_rmb();
if (task->mm)
dumpable = get_dumpable(task->mm);
- if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE))
+ if (dumpable != SUID_DUMP_USER &&
+ !task_ns_capable(task, CAP_SYS_PTRACE))
return -EPERM;
return security_ptrace_access_check(task, mode);
static int ptrace_resume(struct task_struct *child, long request,
unsigned long data)
{
+ bool need_siglock;
+
if (!valid_signal(data))
return -EIO;
user_disable_single_step(child);
}
+ /*
+ * Change ->exit_code and ->state under siglock to avoid the race
+ * with wait_task_stopped() in between; a non-zero ->exit_code will
+ * wrongly look like another report from tracee.
+ *
+ * Note that we need siglock even if ->exit_code == data and/or this
+ * status was not reported yet, the new status must not be cleared by
+ * wait_task_stopped() after resume.
+ *
+ * If data == 0 we do not care if wait_task_stopped() reports the old
+ * status and clears the code too; this can't race with the tracee, it
+ * takes siglock after resume.
+ */
+ need_siglock = data && !thread_group_empty(current);
+ if (need_siglock)
+ spin_lock_irq(&child->sighand->siglock);
child->exit_code = data;
wake_up_state(child, __TASK_TRACED);
+ if (need_siglock)
+ spin_unlock_irq(&child->sighand->siglock);
return 0;
}