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Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/super.c b/fs/super.c
index ea662b0e5e78..b8b6a086c03b 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -469,7 +469,7 @@ struct super_block *sget_userns(struct file_system_type *type,
struct super_block *old;
int err;
- if (!(flags & MS_KERNMOUNT) &&
+ if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) &&
!(type->fs_flags & FS_USERNS_MOUNT) &&
!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
@@ -499,7 +499,7 @@ retry:
}
if (!s) {
spin_unlock(&sb_lock);
- s = alloc_super(type, flags, user_ns);
+ s = alloc_super(type, (flags & ~MS_SUBMOUNT), user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
@@ -540,8 +540,15 @@ struct super_block *sget(struct file_system_type *type,
{
struct user_namespace *user_ns = current_user_ns();
+ /* We don't yet pass the user namespace of the parent
+ * mount through to here so always use &init_user_ns
+ * until that changes.
+ */
+ if (flags & MS_SUBMOUNT)
+ user_ns = &init_user_ns;
+
/* Ensure the requestor has permissions over the target filesystem */
- if (!(flags & MS_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN))
+ if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
return sget_userns(type, test, set, flags, user_ns, data);