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>
This commit is contained in:
Eric W. Biederman 2014-08-13 01:33:38 -07:00
parent 5d01410fe4
commit 3e1866410f

View File

@ -2098,7 +2098,13 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
}
if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
!(mnt_flags & MNT_NODEV)) {
return -EPERM;
/* 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)) {