Commit 3e186641 authored Aug 13, 2014 by Eric W. Biederman

mnt: Implicitly add MNT_NODEV on remount when it was implicitly added by mount



Now that remount is properly enforcing the rule that you can't remove
nodev at least sandstorm.io is breaking when performing a remount.

It turns out that there is an easy intuitive solution implicitly
add nodev on remount when nodev was implicitly added on mount.

Tested-by: Cedric Bosdonnat <cbosdonnat@suse.com>
Tested-by: Richard Weinberger <richard@nod.at>
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent 5d01410f

fs/namespace.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -2098,8 +2098,14 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
		}
		if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
		!(mnt_flags & MNT_NODEV)) {
		/* Was the nodev implicitly added in mount? */
		if ((mnt->mnt_ns->user_ns != &init_user_ns) &&
		!(sb->s_type->fs_flags & FS_USERNS_DEV_MOUNT)) {
		mnt_flags \|= MNT_NODEV;
		} else {
		return -EPERM;
		}
		}
		if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) &&
		!(mnt_flags & MNT_NOSUID)) {
		return -EPERM;