netfilter: nf_ct_sip: fix IPv6 address parsing
Within SIP messages IPv6 addresses are enclosed in square brackets in most
cases, with the exception of the "received=" header parameter. Currently
the helper fails to parse enclosed addresses.
This patch:
- changes the SIP address parsing function to enforce square brackets
when required, and accept them when not required but present, as
recommended by RFC 5118.
- adds a new SDP address parsing function that never accepts square
brackets since SDP doesn't use them.
With these changes, the SIP helper correctly parses all test messages
from RFC 5118 (Session Initiation Protocol (SIP) Torture Test Messages
for Internet Protocol Version 6 (IPv6)).
Signed-off-by: Patrick McHardy <kaber@trash.net>
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 2fb6669..5c0a112 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -183,12 +183,12 @@
return len + digits_len(ct, dptr, limit, shift);
}
-static int parse_addr(const struct nf_conn *ct, const char *cp,
- const char **endp, union nf_inet_addr *addr,
- const char *limit)
+static int sip_parse_addr(const struct nf_conn *ct, const char *cp,
+ const char **endp, union nf_inet_addr *addr,
+ const char *limit, bool delim)
{
const char *end;
- int ret = 0;
+ int ret;
if (!ct)
return 0;
@@ -197,16 +197,28 @@
switch (nf_ct_l3num(ct)) {
case AF_INET:
ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end);
+ if (ret == 0)
+ return 0;
break;
case AF_INET6:
+ if (cp < limit && *cp == '[')
+ cp++;
+ else if (delim)
+ return 0;
+
ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end);
+ if (ret == 0)
+ return 0;
+
+ if (end < limit && *end == ']')
+ end++;
+ else if (delim)
+ return 0;
break;
default:
BUG();
}
- if (ret == 0 || end == cp)
- return 0;
if (endp)
*endp = end;
return 1;
@@ -219,7 +231,7 @@
union nf_inet_addr addr;
const char *aux = dptr;
- if (!parse_addr(ct, dptr, &dptr, &addr, limit)) {
+ if (!sip_parse_addr(ct, dptr, &dptr, &addr, limit, true)) {
pr_debug("ip: %s parse failed.!\n", dptr);
return 0;
}
@@ -296,7 +308,7 @@
return 0;
dptr += shift;
- if (!parse_addr(ct, dptr, &end, addr, limit))
+ if (!sip_parse_addr(ct, dptr, &end, addr, limit, true))
return -1;
if (end < limit && *end == ':') {
end++;
@@ -550,7 +562,7 @@
if (ret == 0)
return ret;
- if (!parse_addr(ct, dptr + *matchoff, &c, addr, limit))
+ if (!sip_parse_addr(ct, dptr + *matchoff, &c, addr, limit, true))
return -1;
if (*c == ':') {
c++;
@@ -599,7 +611,7 @@
unsigned int dataoff, unsigned int datalen,
const char *name,
unsigned int *matchoff, unsigned int *matchlen,
- union nf_inet_addr *addr)
+ union nf_inet_addr *addr, bool delim)
{
const char *limit = dptr + datalen;
const char *start, *end;
@@ -613,7 +625,7 @@
return 0;
start += strlen(name);
- if (!parse_addr(ct, start, &end, addr, limit))
+ if (!sip_parse_addr(ct, start, &end, addr, limit, delim))
return 0;
*matchoff = start - dptr;
*matchlen = end - start;
@@ -675,6 +687,47 @@
return 1;
}
+static int sdp_parse_addr(const struct nf_conn *ct, const char *cp,
+ const char **endp, union nf_inet_addr *addr,
+ const char *limit)
+{
+ const char *end;
+ int ret;
+
+ memset(addr, 0, sizeof(*addr));
+ switch (nf_ct_l3num(ct)) {
+ case AF_INET:
+ ret = in4_pton(cp, limit - cp, (u8 *)&addr->ip, -1, &end);
+ break;
+ case AF_INET6:
+ ret = in6_pton(cp, limit - cp, (u8 *)&addr->ip6, -1, &end);
+ break;
+ default:
+ BUG();
+ }
+
+ if (ret == 0)
+ return 0;
+ if (endp)
+ *endp = end;
+ return 1;
+}
+
+/* skip ip address. returns its length. */
+static int sdp_addr_len(const struct nf_conn *ct, const char *dptr,
+ const char *limit, int *shift)
+{
+ union nf_inet_addr addr;
+ const char *aux = dptr;
+
+ if (!sdp_parse_addr(ct, dptr, &dptr, &addr, limit)) {
+ pr_debug("ip: %s parse failed.!\n", dptr);
+ return 0;
+ }
+
+ return dptr - aux;
+}
+
/* SDP header parsing: a SDP session description contains an ordered set of
* headers, starting with a section containing general session parameters,
* optionally followed by multiple media descriptions.
@@ -686,10 +739,10 @@
*/
static const struct sip_header ct_sdp_hdrs[] = {
[SDP_HDR_VERSION] = SDP_HDR("v=", NULL, digits_len),
- [SDP_HDR_OWNER_IP4] = SDP_HDR("o=", "IN IP4 ", epaddr_len),
- [SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", epaddr_len),
- [SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", epaddr_len),
- [SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", epaddr_len),
+ [SDP_HDR_OWNER_IP4] = SDP_HDR("o=", "IN IP4 ", sdp_addr_len),
+ [SDP_HDR_CONNECTION_IP4] = SDP_HDR("c=", "IN IP4 ", sdp_addr_len),
+ [SDP_HDR_OWNER_IP6] = SDP_HDR("o=", "IN IP6 ", sdp_addr_len),
+ [SDP_HDR_CONNECTION_IP6] = SDP_HDR("c=", "IN IP6 ", sdp_addr_len),
[SDP_HDR_MEDIA] = SDP_HDR("m=", NULL, media_len),
};
@@ -775,8 +828,8 @@
if (ret <= 0)
return ret;
- if (!parse_addr(ct, dptr + *matchoff, NULL, addr,
- dptr + *matchoff + *matchlen))
+ if (!sdp_parse_addr(ct, dptr + *matchoff, NULL, addr,
+ dptr + *matchoff + *matchlen))
return -1;
return 1;
}