From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Date: Fri, 18 Jul 2014 22:13:03 +0000 Subject: Re: [PATCH net] net: sctp: inherit auth_capable on INIT collisions Message-Id: <53C99BEF.1010203@redhat.com> List-Id: References: <1405620319-2021-1-git-send-email-dborkman@redhat.com> <53C93157.1050002@gmail.com> <53C972BE.5090700@redhat.com> <53C998DE.2030805@gmail.com> In-Reply-To: <53C998DE.2030805@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Vlad Yasevich Cc: davem@davemloft.net, jgunthorpe@obsidianresearch.com, netdev@vger.kernel.org, linux-sctp@vger.kernel.org On 07/18/2014 11:59 PM, Vlad Yasevich wrote: > On 07/18/2014 03:17 PM, Daniel Borkmann wrote: >> On 07/18/2014 04:38 PM, Vlad Yasevich wrote: >> ... >>> Why is the original value of asoc->peer.auth_capable = 0? >>> In case of collision, asoc is the old association that >>> existed on the system. That association was created as part of >>> sending the INIT. If it is processing a duplicate COOKIE-ECHO >>> as you say, then it has already processed the INIT-ACK and >>> should have determined that the peer is auth capable. >>> >>> Thus the capability of the new and the old associations should >>> be same if we are in fact processing case B (collision). >>> >>> If not, then something else if wrong and my guess is that all >>> other capabilities would be wrong too. >> >> I agree that they might likely also be flawed. >> >> Ok, let me dig further. > > So I think I know why case D ends up not authenticating the COOKIE-ACK. > Most likely the reason is the following statement: > repl = sctp_make_cookie_ack(new_asoc, chunk); > > Note that we use new_asoc, instead of current asoc. Thanks, I will give it a try. Btw, noticed also that when we have AUTH + COOKIE_ECHO collisions, we don't seem to handle them properly either. The normal case works fine, but in case of a collision both sides seem to use wrong RANDOM etc params, and thus discard the handshake due to bad signature. > Not sure why case B is dumping core yet.