releases/4.9.124/netfilter-conntrack-dccp-treat-sync-syncack-as-invalid-if-no-prior-state.patch

From 6613b6173dee098997229caf1f3b961c49da75e6 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Tue, 17 Jul 2018 21:03:15 +0200
Subject: netfilter: conntrack: dccp: treat SYNC/SYNCACK as invalid if no prior state

From: Florian Westphal <fw@strlen.de>

commit 6613b6173dee098997229caf1f3b961c49da75e6 upstream.

When first DCCP packet is SYNC or SYNCACK, we insert a new conntrack
that has an un-initialized timeout value, i.e. such entry could be
reaped at any time.

Mark them as INVALID and only ignore SYNC/SYNCACK when connection had
an old state.

Reported-by: syzbot+6f18401420df260e37ed@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/netfilter/nf_conntrack_proto_dccp.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/net/netfilter/nf_conntrack_proto_dccp.c
+++ b/net/netfilter/nf_conntrack_proto_dccp.c
@@ -244,14 +244,14 @@ dccp_state_table[CT_DCCP_ROLE_MAX + 1][D
 		 * We currently ignore Sync packets
 		 *
 		 *	sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
-			sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
+			sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 		},
 		[DCCP_PKT_SYNCACK] = {
 		/*
 		 * We currently ignore SyncAck packets
 		 *
 		 *	sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
-			sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
+			sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 		},
 	},
 	[CT_DCCP_ROLE_SERVER] = {
@@ -372,14 +372,14 @@ dccp_state_table[CT_DCCP_ROLE_MAX + 1][D
 		 * We currently ignore Sync packets
 		 *
 		 *	sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
-			sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
+			sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 		},
 		[DCCP_PKT_SYNCACK] = {
 		/*
 		 * We currently ignore SyncAck packets
 		 *
 		 *	sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
-			sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
+			sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
 		},
 	},
 };