netdev - [PATCH 3/7] netfilter: conntrack: sctp: use distinct states for new SCTP connections

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Message-Id: <20200125173415.191571-4-pablo@netfilter.org>
Date:   Sat, 25 Jan 2020 18:34:11 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 3/7] netfilter: conntrack: sctp: use distinct states for new SCTP connections

From: Jiri Wiesner <jwiesner@...e.com>

The netlink notifications triggered by the INIT and INIT_ACK chunks
for a tracked SCTP association do not include protocol information
for the corresponding connection - SCTP state and verification tags
for the original and reply direction are missing. Since the connection
tracking implementation allows user space programs to receive
notifications about a connection and then create a new connection
based on the values received in a notification, it makes sense that
INIT and INIT_ACK notifications should contain the SCTP state
and verification tags available at the time when a notification
is sent. The missing verification tags cause a newly created
netfilter connection to fail to verify the tags of SCTP packets
when this connection has been created from the values previously
received in an INIT or INIT_ACK notification.

A PROTOINFO event is cached in sctp_packet() when the state
of a connection changes. The CLOSED and COOKIE_WAIT state will
be used for connections that have seen an INIT and INIT_ACK chunk,
respectively. The distinct states will cause a connection state
change in sctp_packet().

Signed-off-by: Jiri Wiesner <jwiesner@...e.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_conntrack_proto_sctp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 0399ae8f1188..4f897b14b606 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -114,7 +114,7 @@ static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 	{
 /*	ORIGINAL	*/
 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
-/* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
+/* init         */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCW, sHA},
 /* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL, sHA},
 /* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
 /* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL, sSS},
@@ -130,7 +130,7 @@ static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 /*	REPLY	*/
 /*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS, sHA */
 /* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},/* INIT in sCL Big TODO */
-/* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
+/* init_ack     */ {sIV, sCW, sCW, sCE, sES, sSS, sSR, sSA, sIV, sHA},
 /* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV, sCL},
 /* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV, sSR},
 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV, sHA},
@@ -316,7 +316,7 @@ sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
 			ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
 		}

-		ct->proto.sctp.state = new_state;
+		ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
 	}

 	return true;
-- 
2.11.0