Subject: Re: [PATCH nf] netfilter: check SCTP_CID_SHUTDOWN_ACK for vtag setting in sctp_new

From: Florian Westphal <[email-masked]>
Date: Fri, 26 Jan 2024 01:01:05 +0100

Xin Long <[email-masked]> wrote:
> The annotation says in sctp_new(): "If it is a shutdown ack OOTB packet, we
> expect a return shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8)".
> However, it does not check SCTP_CID_SHUTDOWN_ACK before setting vtag[REPLY]
> in the conntrack entry(ct).
> 
> Because of that, if the ct in Router disappears for some reason in [1]
> with the packet sequence like below:
 
Seems to be day 0 bug, so
Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")