sched: move no_new_privs into new atomic flags
Since seccomp transitions between threads requires updates to the
no_new_privs flag to be atomic, the flag must be part of an atomic flag
set. This moves the nnp flag into a separate task field, and introduces
accessors.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 306f4f0..0fd1905 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1307,13 +1307,12 @@
* execve */
unsigned in_iowait:1;
- /* task may not gain privileges */
- unsigned no_new_privs:1;
-
/* Revert to default priority/policy when forking */
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
+ unsigned long atomic_flags; /* Flags needing atomic access. */
+
pid_t pid;
pid_t tgid;
@@ -1967,6 +1966,19 @@
current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
}
+/* Per-process atomic flags. */
+#define PFA_NO_NEW_PRIVS 0x00000001 /* May not gain new privileges. */
+
+static inline bool task_no_new_privs(struct task_struct *p)
+{
+ return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
+}
+
+static inline void task_set_no_new_privs(struct task_struct *p)
+{
+ set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
+}
+
/*
* task->jobctl flags
*/