On Sun, Apr 01, 2012 at 06:55:22PM +0200, Eric Dumazet wrote: > On Sun, 2012-04-01 at 18:43 +0200, Pablo Neira Ayuso wrote: > > On Sun, Apr 01, 2012 at 10:22:50PM +0800, Changli Gao wrote: > > > We should check the length of the data before dereferencing it when parsing > > > the TCP options. > > > > > > Signed-off-by: Changli Gao <xiaosuo@xxxxxxxxx> > > > --- > > > net/netfilter/nf_conntrack_proto_tcp.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c > > > index 361eade..9e446c5 100644 > > > --- a/net/netfilter/nf_conntrack_proto_tcp.c > > > +++ b/net/netfilter/nf_conntrack_proto_tcp.c > > > @@ -404,6 +404,8 @@ static void tcp_options(const struct sk_buff *skb, > > > length--; > > > continue; > > > default: > > > + if (length < 2) > > > + return; > > > opsize=*ptr++; > > > if (opsize < 2) /* "silly options" */ > > > return; > > > > length is always multiple of 4: > > > > int length = (tcph->doff*4) - sizeof(struct tcphdr); > > -- > > initial value yes, but it can change in the loop. Indeed, then I think we need a similar patch for tcp_parse_options() in net/ipv4/tcp_input.c -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
