netfilter: nf_nat_sip: fix via header translation with multiple parameters

Via-headers are parsed beginning at the first character after the Via-address.
When the address is translated first and its length decreases, the offset to
start parsing at is incorrect and header parameters might be missed.

Update the offset after translating the Via-address to fix this.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index eef8f29e8bf870488712facca5f3a84b25f2a90c..4ad9cf1739922cfb4b13d3135d01381dd70bf0be 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_sip.c
+++ b/net/ipv4/netfilter/nf_nat_sip.c
@@ -148,7 +148,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
        if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
                                    hdr, NULL, &matchoff, &matchlen,
                                    &addr, &port) > 0) {
-               unsigned int matchend, poff, plen, buflen, n;
+               unsigned int olen, matchend, poff, plen, buflen, n;
                char buffer[sizeof("nnn.nnn.nnn.nnn:nnnnn")];
 
                /* We're only interested in headers related to this
@@ -163,11 +163,12 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
                                goto next;
                }
 
+               olen = *datalen;
                if (!map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen,
                              &addr, port))
                        return NF_DROP;
 
-               matchend = matchoff + matchlen;
+               matchend = matchoff + matchlen + *datalen - olen;
 
                /* The maddr= parameter (RFC 2361) specifies where to send
                 * the reply. */