[NETFILTER]: SIP conntrack: fix skipping over user info in SIP headers

When trying to skip over the username in the Contact header, stop at the
end of the line if no @ is found to avoid mangling following headers.
We don't need to worry about continuation lines because we search inside
a SIP URI.

Fixes Netfilter Bugzilla #532.
Signed-off-by: Lars Immisch <lars@ibp.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_conntrack_sip.c

@@ -283,8 +283,14 @@ static int skp_epaddr_len(const char *dptr, const char *limit, int *shift)
 {
 	int s = *shift;
 
-	for (; dptr <= limit && *dptr != '@'; dptr++)
+	/* Search for @, but stop at the end of the line.
+	 * We are inside a sip: URI, so we don't need to worry about
+	 * continuation lines. */
+	while (dptr <= limit &&
+	       *dptr != '@' && *dptr != '\r' && *dptr != '\n') {
 		(*shift)++;
+		dptr++;
+	}
 
 	if (*dptr == '@') {
 		dptr++;

net/netfilter/nf_conntrack_sip.c

@@ -303,8 +303,14 @@ static int skp_epaddr_len(struct nf_conn *ct, const char *dptr,
 {
 	int s = *shift;
 
-	for (; dptr <= limit && *dptr != '@'; dptr++)
+	/* Search for @, but stop at the end of the line.
+	 * We are inside a sip: URI, so we don't need to worry about
+	 * continuation lines. */
+	while (dptr <= limit &&
+	       *dptr != '@' && *dptr != '\r' && *dptr != '\n') {
 		(*shift)++;
+		dptr++;
+	}
 
 	if (*dptr == '@') {
 		dptr++;