From 4a5cc84ae7e19fb7a72a30332ba67af43e0ad1ad Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Tue, 30 Aug 2011 15:45:10 +0200 Subject: [PATCH] netfilter: nf_ct_tcp: fix incorrect handling of invalid TCP option 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 Signed-off-by: Patrick McHardy --- net/netfilter/nf_conntrack_proto_tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 37bf94394be0..afc4ab7cfe01 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 -- 2.20.1