From 5f96bf92e79b7d7e05fd2a6ed49f96824d16bee0 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 13 Aug 2014 01:33:38 -0700 Subject: [PATCH] mnt: Implicitly add MNT_NODEV on remount when it was implicitly added by mount commit 3e1866410f11356a9fd869beb3e95983dc79c067 upstream. 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 Signed-off-by: "Eric W. Biederman" Signed-off-by: Luis Henriques --- fs/namespace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index f24161a45b06..e718c7a0437a 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1973,7 +1973,13 @@ 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)) {