netdev - [PATCH 2/4] sctp: Add check for the TSN field of the SHUTDOWN chunk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1224641327-11913-3-git-send-email-vladislav.yasevich@hp.com>
Date:	Tue, 21 Oct 2008 22:08:45 -0400
From:	Vlad Yasevich <vladislav.yasevich@...com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, linux-sctp@...r.kernel.org,
	Wei Yongjun <yjwei@...fujitsu.com>,
	Vlad Yasevich <vladislav.yasevich@...com>
Subject: [PATCH 2/4] sctp: Add check for the TSN field of the SHUTDOWN chunk

From: Wei Yongjun <yjwei@...fujitsu.com>

If SHUTDOWN chunk is received Cumulative TSN Ack beyond the max tsn currently
send, SHUTDOWN chunk be accepted and the association will be broken. New data
is send, but after received SACK it will be drop because TSN in SACK is less
than the Cumulative TSN, data will be retrans again and again even if correct
SACK is received.

The packet sequence is like this:

Endpoint A                       Endpoint B       ULP
(ESTABLISHED)                    (ESTABLISHED)

               <-----------      DATA (TSN=x-1)

               <-----------      DATA (TSN=x)

  SHUTDOWN     ----------->      (Now Cumulative TSN=x+1000)
  (TSN=x+1000)
               <-----------      DATA (TSN=x+1)

  SACK         ----------->      drop the SACK
  (TSN=x+1)
               <-----------      DATA (TSN=x+1)(retrans)

This patch fix this problem by terminating the association and respond to
the sender with an ABORT.

Signed-off-by: Wei Yongjun <yjwei@...fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@...com>
---
 net/sctp/sm_statefuns.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index d4c3fbc..12f6217 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2544,6 +2544,7 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
 	sctp_shutdownhdr_t *sdh;
 	sctp_disposition_t disposition;
 	struct sctp_ulpevent *ev;
+	__u32 ctsn;
 
 	if (!sctp_vtag_verify(chunk, asoc))
 		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
@@ -2558,6 +2559,14 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
 	sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
 	skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
 	chunk->subh.shutdown_hdr = sdh;
+	ctsn = ntohl(sdh->cum_tsn_ack);
+
+	/* If Cumulative TSN Ack beyond the max tsn currently
+	 * send, terminating the association and respond to the
+	 * sender with an ABORT.
+	 */
+	if (!TSN_lt(ctsn, asoc->next_tsn))
+		return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
 
 	/* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
 	 * When a peer sends a SHUTDOWN, SCTP delivers this notification to
-- 
1.5.3.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html