Hi Pablo,

Note that this code does not exist in the tree anymore. I'm not sure
if this problem still exists upstream, this patch does not apply to
nf.git. This fix should only go for -stable maintainers.

Right, the vulnerability has been fixed by the refactor commit fe2d0020994cd
("netfilter: nat: remove l4proto->in_range"), but this patch is a part of
a full re-work of the code and doesn't backport very cleanly to the LTS
branches. So this fix is only applicable to the 4.19, 4.14, 4.9, and 4.4 LTS
branches. I missed the -stable email, but will re-add it to this thread with
the re-worked patch.

Thanks,
Will

On 07/31/2020, Pablo Neira Ayuso wrote:

Hi William,

On Fri, Jul 31, 2020 at 12:26:11AM +0000, William Mcvicker wrote:

quoted

Hi Pablo,

Yes, I believe this oops is only triggered by userspace when the user
specifically passes in an invalid nf_nat_l3protos index. I'm happy to re-work
the patch to check for this in ctnetlink_create_conntrack().

Great.

Note that this code does not exist in the tree anymore. I'm not sure
if this problem still exists upstream, this patch does not apply to
nf.git. This fix should only go for -stable maintainers.

quoted

quoted

BTW, do you have a Fixes: tag for this? This will be useful for
-stable maintainer to pick up this fix.

Regarding the Fixes: tag, I don't have one offhand since this bug was reported
to me, but I can search through the code history to find the commit that
exposed this vulnerability.

That would be great.

Thank you.