Messages in this thread | | | Date | Wed, 17 Sep 2014 16:31:35 -0400 | From | Shea Levy <> | Subject | Re: Setting FS_USERNS_MOUNT in btrfs_fs_type.fs_flags |
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On Wed, Sep 17, 2014 at 09:12:14AM -0700, Zach Brown wrote: > On Wed, Sep 17, 2014 at 04:54:48AM +0100, Al Viro wrote: > > On Tue, Sep 16, 2014 at 11:05:00PM -0400, Shea Levy wrote: > > > Hi all, > > > > > > What work would be required to mark btrfs_fs_type with FS_USERNS_MOUNT > > > so that btrfs images can be mounted by unprivileged users within a user > > > namespace (along with something like [1])? I'd like to be able to create > > > disk images without having to start a VM (and --rootdir isn't flexible > > > enough because I want to make subvolumes). > > > > Er... Which is to say, you have an audit of btrfs code making sure that > > it can cope with arbitrary image hand-crafted by potential attacker? > > It definitely can't cope. The easiest places to find bugs are the > hundreds of BUG_ON() sites, many can be triggered by on-disk structures. > The sheer volume of those makes me trust that you could find much worse > if you did a thorough audit. > > - z > (fun related fact: distros automount btrfs images)
OK, so it seems like the answer to my question is "a helluva lot". Guess I won't count on seeing it any time soon :)
Thanks, Shea
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