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>

2 files changed, 3 insertions, 3 deletions

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index f0652578af75..d2596136b0d1 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -241,7 +241,7 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
          * This avoids scenarios where unprivileged tasks can affect the
          * behavior of privileged children.
          */
-        if (!current->no_new_privs &&
+        if (!task_no_new_privs(current) &&
             security_capable_noaudit(current_cred(), current_user_ns(),
                                      CAP_SYS_ADMIN) != 0)
                 return -EACCES;
diff --git a/kernel/sys.c b/kernel/sys.c
index 66a751ebf9d9..ce8129192a26 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1990,12 +1990,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                 if (arg2 != 1 || arg3 || arg4 || arg5)
                         return -EINVAL;
 
-                current->no_new_privs = 1;
+                task_set_no_new_privs(current);
                 break;
         case PR_GET_NO_NEW_PRIVS:
                 if (arg2 || arg3 || arg4 || arg5)
                         return -EINVAL;
-                return current->no_new_privs ? 1 : 0;
+                return task_no_new_privs(current) ? 1 : 0;
         case PR_GET_THP_DISABLE:
                 if (arg2 || arg3 || arg4 || arg5)
                         return -EINVAL;