netfilter: nf_conntrack_sip: CSeq 0 is a valid CSeq

Do not drop packet when CSeq is 0 as 0 is also a valid value for CSeq.

simple_strtoul() will return 0 either when all digits are 0
or if there are no digits at all. Therefore when simple_strtoul()
returns 0 we check if first character is digit 0 or not.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 8d9db9d4702b06965a896b3e85a3254aa2e3191b..7d77217de6a3b4e7821452f721c0902ca6fecd81 100644 (file)
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1383,7 +1383,7 @@ static int process_sip_response(struct sk_buff *skb, unsigned int protoff,
                return NF_DROP;
        }
        cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
-       if (!cseq) {
+       if (!cseq && *(*dptr + matchoff) != '0') {
                nf_ct_helper_log(skb, ct, "cannot get cseq");
                return NF_DROP;
        }
@@ -1446,7 +1446,7 @@ static int process_sip_request(struct sk_buff *skb, unsigned int protoff,
                        return NF_DROP;
                }
                cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
-               if (!cseq) {
+               if (!cseq && *(*dptr + matchoff) != '0') {
                        nf_ct_helper_log(skb, ct, "cannot get cseq");
                        return NF_DROP;
                }