From f4a87e7bd2eaef26a3ca25437ce8b807de2966ad Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 30 Sep 2013 08:51:46 +0100 Subject: netfilter: synproxy: fix BUG_ON triggered by corrupt TCP packets TCP packets hitting the SYN proxy through the SYNPROXY target are not validated by TCP conntrack. When th->doff is below 5, an underflow happens when calculating the options length, causing skb_header_pointer() to return NULL and triggering the BUG_ON(). Handle this case gracefully by checking for NULL instead of using BUG_ON(). Reported-by: Martin Topholm Tested-by: Martin Topholm Signed-off-by: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_synproxy.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h index 806f54a290d6..f572f313d6f1 100644 --- a/include/net/netfilter/nf_conntrack_synproxy.h +++ b/include/net/netfilter/nf_conntrack_synproxy.h @@ -56,7 +56,7 @@ struct synproxy_options { struct tcphdr; struct xt_synproxy_info; -extern void synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, +extern bool synproxy_parse_options(const struct sk_buff *skb, unsigned int doff, const struct tcphdr *th, struct synproxy_options *opts); extern unsigned int synproxy_options_size(const struct synproxy_options *opts); -- cgit v1.2.3