[SRU][Raring][PATCH 0/1] ipvs: add backup_only flag to avoid loops

[Luis Henriques]

Luis Henriques <luis.henriques at canonical.com> writes:

> SRU Justification:
>
> Impact:
>
> A NULL pointer dereferrence will occur when a user adds an IPVS
> service.  This occurs since kernel 3.8.0-28.41 (Raring), after commit:
>
>   dc7b3eb ipvs: Fix reuse connection if real server is dead
>
> The NULL pointer occurs when accessing the ipvs variable in line 1658:
>
>    1658 if (unlikely(sysctl_expire_nodest_conn(ipvs)) && cp && cp->dest &&
>    1659 unlikely(!atomic_read(&cp->dest->weight)) && !iph.fragoffs &&
>    1660 is_new_conn(skb, &iph)) {
>    1661 ip_vs_conn_expire_now(cp);
>    1662 __ip_vs_conn_put(cp);
>    1663 cp = NULL;
>    1664 }
>
> Mainline kernel has this variable initialised earlier, with commit:
>
>  0c12582 ipvs: add backup_only flag to avoid loops
>
> Fix:
>
> Apply commit 0c12582 "ipvs: add backup_only flag to avoid loops" fix
> the problem.  Bug reporter has claimed success with a test kernel that
> contains this commit.
>
> Testcase:
>
> Simply running the command:
>
>  sudo ipvsadm -A -u 10.0.50.4:53
>
> Will trigger the bug.

Kamal,

I haven't tested this with a vanilla 3.8.y.z kernel, but I believe
this patch should also be applied there.

Cheers,
-- 
Luis


>
> Julian Anastasov (1):
>   ipvs: add backup_only flag to avoid loops
>
>  Documentation/networking/ipvs-sysctl.txt |  7 +++++++
>  include/net/ip_vs.h                      | 12 ++++++++++++
>  net/netfilter/ipvs/ip_vs_core.c          | 12 ++++++++----
>  net/netfilter/ipvs/ip_vs_ctl.c           |  7 +++++++
>  4 files changed, 34 insertions(+), 4 deletions(-)
>
> -- 
> 1.8.3.2