Re: [PATCH v3 0/7] User namespace mount updates

Richard Weinberger
2015-11-17T20:12:22Z

Am 17.11.2015 um 20:25 schrieb Octavian Purdila:
> On Tue, Nov 17, 2015 at 9:21 PM, Seth Forshee
> <seth.forshee@canonical.com> wrote:
>>
>> On Tue, Nov 17, 2015 at 08:12:31PM +0100, Richard Weinberger wrote:
>>> On Tue, Nov 17, 2015 at 7:34 PM, Seth Forshee
>>> <seth.forshee@canonical.com> wrote:
>>>> On Tue, Nov 17, 2015 at 05:55:06PM +0000, Al Viro wrote:
>>>>> On Tue, Nov 17, 2015 at 11:25:51AM -0600, Seth Forshee wrote:
>>>>>
>>>>>> Shortly after that I plan to follow with support for ext4. I've been
>>>>>> fuzzing ext4 for a while now and it has held up well, and I'm currently
>>>>>> working on hand-crafted attacks. Ted has commented privately (to others,
>>>>>> not to me personally) that he will fix bugs for such attacks, though I
>>>>>> haven't seen any public comments to that effect.
>>>>>
>>>>> _Static_ attacks, or change-image-under-mounted-fs attacks?
>>>>
>>>> Right now only static attacks, change-image-under-mounted-fs attacks
>>>> will be next.
>>>
>>> Do we *really* need to enable unprivileged mounting of kernel filesystems?
>>> What about just enabling fuse and implement ext4 and friends as fuse
>>> filesystems?
>>> Using the approaching Linux Kernel Libary[1] this is easy.
>>
>> I haven't looked at this project, but I'm guessing that programs must be
>> written specifically to make use of it? I.e. you can't just use the
>> mount syscall, and thus all existing software still doesn't work?
>>
>
> The projects includes a lklfuse program that uses fuse to mount a
> fileystem image.

Cool. I gave it a try.
It seems to work fine, but only if I run it in foreground (using -d)
otherwise fuse blocks every filesystem request.

Thanks,
//richard