Fix user struct leakage with locked IPC shem segment

[firefly-linux-kernel-4.4.55.git] / ipc / shm.c

diff --git a/ipc/shm.c b/ipc/shm.c
index d88ac5a07ec72464266227856238964595303825..a86a3a5c8a19589698dc8b9ec555e1d98891466d 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -716,7 +716,7 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
                        struct user_struct * user = current->user;
                        if (!is_file_hugepages(shp->shm_file)) {
                                err = shmem_lock(shp->shm_file, 1, user);
-                               if (!err) {
+                               if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
                                        shp->shm_perm.mode |= SHM_LOCKED;
                                        shp->mlock_user = user;
                                }