From: Nazarov Sergey <s-naza...@yandex.ru>
Date: Tue, 12 Feb 2019 18:10:03 +0300
> Since cipso_v4_error might be called from different network stack layers, we
> can't safely use icmp_send there.
> icmp_send copies IP options with ip_option_echo, which uses IPCB to take
> access to IP header compiled data.
> But after commit 971f10ec ("tcp: better TCP_SKB_CB layout to reduce cache
> line misses"), IPCB can't be used
> above IP layer.
> This patch fixes the problem by creating in cipso_v4_error a local copy of
> compiled IP options and using it with
> introduced __icmp_send function. This looks some overloaded, but in quite
> rare error conditions only.
>
> The original discussion is here:
> https://lore.kernel.org/linux-security-module/16659801547571...@sas1-890ba5c2334a.qloud-c.yandex.net/
>
> Signed-off-by: Sergey Nazarov <s-naza...@yandex.ru>
This problem is not unique to Cipso, net/atm/clip.c's error handler
has the same exact issue.
I didn't scan more of the tree, there are probably a couple more
locations as well.
