[PATCH 12/25] netfilter: nf_conntrack_h323: fix off-by-one in DecodeQ931

[Pablo Neira Ayuso]

From: Toby DiPasquale <t...@cbcg.net>

This patch corrects an off-by-one error in the DecodeQ931 function in
the nf_conntrack_h323 module. This error could result in reading off
the end of a Q.931 frame.

Signed-off-by: Toby DiPasquale <t...@cbcg.net>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_conntrack_h323_asn1.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_h323_asn1.c 
b/net/netfilter/nf_conntrack_h323_asn1.c
index bcd5ed6..89b2e46 100644
--- a/net/netfilter/nf_conntrack_h323_asn1.c
+++ b/net/netfilter/nf_conntrack_h323_asn1.c
@@ -846,9 +846,10 @@ int DecodeQ931(unsigned char *buf, size_t sz, Q931 *q931)
        sz -= len;
 
        /* Message Type */
-       if (sz < 1)
+       if (sz < 2)
                return H323_ERROR_BOUND;
        q931->MessageType = *p++;
+       sz--;
        PRINT("MessageType = %02X\n", q931->MessageType);
        if (*p & 0x80) {
                p++;
-- 
2.1.4