Unbreak mount_capable()

In "consolidate the capability checks in sget_{fc,userns}())" the
wrong argument had been passed to mount_capable() by sget_fc().
That mistake had been further obscured later, when switching
mount_capable() to fs_context has moved the calculation of
bogus argument from sget_fc() to mount_capable() itself.  It
should've been fc->user_ns all along.

Screwed-up-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Christian Brauner <christian@brauner.io>
Tested-by: Christian Brauner <christian@brauner.io>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/super.c b/fs/super.c
index 113c58f194255e3fc57166467018d5eab565548a..5960578a40760a26bc0ecd88e28177ce748f4380 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -478,13 +478,10 @@ EXPORT_SYMBOL(generic_shutdown_super);
 
 bool mount_capable(struct fs_context *fc)
 {
-       struct user_namespace *user_ns = fc->global ? &init_user_ns
-                                                   : fc->user_ns;
-
        if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT))
                return capable(CAP_SYS_ADMIN);
        else
-               return ns_capable(user_ns, CAP_SYS_ADMIN);
+               return ns_capable(fc->user_ns, CAP_SYS_ADMIN);
 }
 
 /**