netfilter: nf_nat_sip: fix via header translation with multiple parameters

commit f22eb25cf5b1157b29ef88c793b71972efc47143 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index 80e61e8771b47e9a5c14ebb023f83f2d96cd3aec..6609a842c856e29d2d995afe62c259e482d8d90d 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. */