From 626ac545c12e5f9bffe93086d1d03d26c99987ea Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Tue, 17 Jul 2007 15:28:17 -0400 Subject: [PATCH] user namespace: fix copy_user_ns return value When a CONFIG_USER_NS=n and a user tries to unshare some namespace other than the user namespace, the dummy copy_user_ns returns NULL rather than the old_ns. This value then gets assigned to task->nsproxy->user_ns, so that a subsequent setuid, which uses task->nsproxy->user_ns, causes a NULL pointer deref. Fix this by returning old_ns. Signed-off-by: Serge E. Hallyn Signed-off-by: Linus Torvalds --- include/linux/user_namespace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index bb320573bb9e..1101b0ce878f 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -49,7 +49,7 @@ static inline struct user_namespace *copy_user_ns(int flags, if (flags & CLONE_NEWUSER) return ERR_PTR(-EINVAL); - return NULL; + return old_ns; } static inline void put_user_ns(struct user_namespace *ns) -- GitLab