[Lucid, Maverick, Natty] SRU: Fix panic after nfs_umount

[Brad Figg]

On 12/09/2010 07:58 AM, Stefan Bader wrote:
> SRU justification:
>
> Impact: When trying to mount an export where server and client have no common
> authentication method, the client will abort the mount by sending an advisory
> unmount message to the server. A bug in the RPC client setup causes the sunrpc
> code to access memory outside an allocated array, which will sooner or later
> cause the kernel to crash.
>
> Fix: Patch from upstream (about to be submitted and targeted for stable too)
> changes the setup to use the actual array size instead of a manually entered number.
>
> Testcase:
>
> Server exports a mount with an authentication method the client does not
> support, eg.:
> [/etc/exports] /srv/foo *(rw,sec=krb5)
>
> Client tries to mount this directory with no special authentication method:
> while true; do mount<server>:/srv/foo /mnt; sync; sleep 1; done
>
> *Note*: This fix is not upstream yet, but is likely to go upstream in that form.
> I just wanted to start the SRU process early due to the fact that it triggers
> quite easily and ends in an odd and fatal mess. It is obvious enough to me and
> has been tested locally.
>
> The change causing the regression has been added in the 2.6.32 time. So all
> kernels between that and now are affected.
>
> -Stefan
>

Acked-by: Brad Figg <brad.figg at canonical.com>

-- 
Brad Figg brad.figg at canonical.com http://www.canonical.com