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authorPatrick McHardy <kaber@trash.net>2013-09-30 08:51:46 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2013-09-30 12:44:38 +0200
commitf4a87e7bd2eaef26a3ca25437ce8b807de2966ad (patch)
tree72359689d53c3ce656b4568f04b8ee92dd2e05f4 /include
parentd1ee4fea0b6946dd8bc61b46db35ea80af7af34b (diff)
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 <mph@one.com> Tested-by: Martin Topholm <mph@one.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include')
-rw-r--r--include/net/netfilter/nf_conntrack_synproxy.h2
1 files changed, 1 insertions, 1 deletions
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);