From: Eric W. Biederman Date: Wed, 13 Aug 2014 08:33:38 +0000 (-0700) Subject: mnt: Implicitly add MNT_NODEV on remount when it was implicitly added by mount X-Git-Tag: Ubuntu-snapdragon-4.4.0-1050.54~9045^2~17 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=3e1866410f11356a9fd869beb3e95983dc79c067;p=mirror_ubuntu-artful-kernel.git 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 Tested-by: Richard Weinberger Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" --- diff --git a/fs/namespace.c b/fs/namespace.c index 5b66b2b3624d..3a1a87dc33df 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -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)) {