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-rw-r--r--kernel/user_namespace.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 9451b12a9b6c..1e34de2fbd60 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -812,14 +812,16 @@ static bool new_idmap_permitted(const struct file *file,
struct user_namespace *ns, int cap_setid,
struct uid_gid_map *new_map)
{
+ const struct cred *cred = file->f_cred;
/* Don't allow mappings that would allow anything that wouldn't
* be allowed without the establishment of unprivileged mappings.
*/
- if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1)) {
+ if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1) &&
+ uid_eq(ns->owner, cred->euid)) {
u32 id = new_map->extent[0].lower_first;
if (cap_setid == CAP_SETUID) {
kuid_t uid = make_kuid(ns->parent, id);
- if (uid_eq(uid, file->f_cred->euid))
+ if (uid_eq(uid, cred->euid))
return true;
}
}