FreeBSD Security Advisory FreeBSD-SA-19:10.ufs

[Doug Hardie]

On Jul 3, 2019, at 05:41, Ed Maste <emaste at freebsd.org> wrote:
> 
>> On Wed, 3 Jul 2019 at 06:05, Doug Hardie <bc979 at lafn.org> wrote:
>> 
>>> Afterwards, reboot the system and run:
>>> 
>>> # fsck -t ufs -f -p -T ufs:-z
>>> 
>>> to clean up your existing filesystems.
>> 
>> After rebooting the system I get:
>> 
>> master# fsck -t ufs -f -p -T ufs:-z
>> /dev/ada0p2: NO WRITE ACCESS
>> /dev/ada0p2: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
>> 
>> Is this expected result or is there a problem here?
> 
> Thanks for reporting this - it looks like some more detail will need
> to be added to the SA. The fsck needs to be run without the filesystem
> being mounted read-write, most likely in single user mode.
> 
> I brought a test system down to single user mode, remounted / as
> read-only, and ran the fsck command as follows:
> 
> # shutdown now
> ...
> Enter full pathname of shell or RETURN for /bin/sh:
> # mount -u -o ro /
> # fsck -t ufs -f -p -T ufs:-z
> /dev/ufsid/5bf225f5889c157d: 28576 files, 304757 used, 27570235 free
> (899 frags, 3446167 blocks, 0.0% fragmentation)
> # exit

That is going to be a bit tricky to do on a headless server that is remote.  None of mine have consoles.  They are all accessed via SSH.  Any ideas how this situation can be handled?

— Doug