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>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 8d9db9d4702b..7d77217de6a3 100644
--- 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;
                 }