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-rw-r--r--net/netfilter/xt_TCPMSS.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index 27241a767f17..c64aca611ac5 100644
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -104,7 +104,7 @@ tcpmss_mangle_packet(struct sk_buff *skb,
tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff);
tcp_hdrlen = tcph->doff * 4;
- if (len < tcp_hdrlen)
+ if (len < tcp_hdrlen || tcp_hdrlen < sizeof(struct tcphdr))
return -1;
if (info->mss == XT_TCPMSS_CLAMP_PMTU) {
@@ -152,6 +152,10 @@ tcpmss_mangle_packet(struct sk_buff *skb,
if (len > tcp_hdrlen)
return 0;
+ /* tcph->doff has 4 bits, do not wrap it to 0 */
+ if (tcp_hdrlen >= 15 * 4)
+ return 0;
+
/*
* MSS Option not found ?! add it..
*/