netdev - [PATCH 6/8] netfilter: nf_ct_tcp: fix incorrect handling of invalid TCP option

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]

Date:	Tue, 30 Aug 2011 16:41:19 +0200
From:	kaber@...sh.net
To:	davem@...emloft.net
Cc:	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH 6/8] netfilter: nf_ct_tcp: fix incorrect handling of invalid TCP option

From: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>

Michael M. Builov reported that in the tcp_options and tcp_sack functions
of netfilter TCP conntrack the incorrect handling of invalid TCP option
with too big opsize may lead to read access beyond tcp-packet or buffer
allocated on stack (netfilter bugzilla #738). The fix is to stop parsing
the options at detecting the broken option.

Signed-off-by: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@...sh.net>
---
 net/netfilter/nf_conntrack_proto_tcp.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index 37bf943..afc4ab7 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -409,7 +409,7 @@ static void tcp_options(const struct sk_buff *skb,
 			if (opsize < 2) /* "silly options" */
 				return;
 			if (opsize > length)
-				break;	/* don't parse partial options */
+				return;	/* don't parse partial options */
 
 			if (opcode == TCPOPT_SACK_PERM
 			    && opsize == TCPOLEN_SACK_PERM)
@@ -469,7 +469,7 @@ static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
 			if (opsize < 2) /* "silly options" */
 				return;
 			if (opsize > length)
-				break;	/* don't parse partial options */
+				return;	/* don't parse partial options */
 
 			if (opcode == TCPOPT_SACK
 			    && opsize >= (TCPOLEN_SACK_BASE
-- 
1.7.2.3

--
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