| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 54/84] mnt: Implicitly add MNT_NODEV on remount when it was implicitly added by mount | Date | Tue, 6 Jan 2015 17:49:57 -0800 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: "Eric W. Biederman" <ebiederm@xmission.com>
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 <cbosdonnat@suse.com> Tested-by: Richard Weinberger <richard@nod.at> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/namespace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/fs/namespace.c +++ b/fs/namespace.c @@ -2100,7 +2100,13 @@ static int do_remount(struct path *path, } 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)) {
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