Kernel memory corruption in CIPSO labeled TCP packets processing.

[Paul Moore]

On Tue, Jan 29, 2019 at 2:23 AM Nazarov Sergey <s-nazarov at yandex.ru> wrote:
> 29.01.2019, 01:18, "Paul Moore" <paul at paul-moore.com>:
> > If we don't pass a skb into ip_options_compile(), meaning both "skb"
> > and "rt" will be NULL, then I don't believe the option data will
> > change. Am I missing something?
>
> I mean, in cipso_v4_error we copy option data from skb before ip_options_compile call:
> +       memcpy(opt->__data, (unsigned char *)&(ip_hdr(skb)[1]), opt->optlen);
> But skb IP header data could be already changed by first call of ip_options_compile
> when packet received.

There are several cases where the stack ends up calling icmp_send()
after the skb has been through ip_options_compile(), that should be
okay.

-- 
paul moore
www.paul-moore.com