]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blobdiff - net/netfilter/nf_conntrack_sip.c
[NETFILTER]: nf_nat_sip: split up SDP mangling
[mirror_ubuntu-bionic-kernel.git] / net / netfilter / nf_conntrack_sip.c
index 217262e23403dfd99897c14009f58f725988083c..f929add324f36e9eb2c3518b7aa63a0502615821 100644 (file)
@@ -60,13 +60,34 @@ unsigned int (*nf_nat_sip_expect_hook)(struct sk_buff *skb,
                                       unsigned int matchlen) __read_mostly;
 EXPORT_SYMBOL_GPL(nf_nat_sip_expect_hook);
 
-unsigned int (*nf_nat_sdp_hook)(struct sk_buff *skb,
-                               const char **dptr,
-                               unsigned int *datalen,
-                               struct nf_conntrack_expect *rtp_exp,
-                               struct nf_conntrack_expect *rtcp_exp)
-                               __read_mostly;
-EXPORT_SYMBOL_GPL(nf_nat_sdp_hook);
+unsigned int (*nf_nat_sdp_addr_hook)(struct sk_buff *skb,
+                                    const char **dptr,
+                                    unsigned int dataoff,
+                                    unsigned int *datalen,
+                                    enum sdp_header_types type,
+                                    enum sdp_header_types term,
+                                    const union nf_inet_addr *addr)
+                                    __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_addr_hook);
+
+unsigned int (*nf_nat_sdp_session_hook)(struct sk_buff *skb,
+                                       const char **dptr,
+                                       unsigned int dataoff,
+                                       unsigned int *datalen,
+                                       const union nf_inet_addr *addr)
+                                       __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_session_hook);
+
+unsigned int (*nf_nat_sdp_media_hook)(struct sk_buff *skb,
+                                     const char **dptr,
+                                     unsigned int *datalen,
+                                     struct nf_conntrack_expect *rtp_exp,
+                                     struct nf_conntrack_expect *rtcp_exp,
+                                     unsigned int mediaoff,
+                                     unsigned int medialen,
+                                     union nf_inet_addr *rtp_addr)
+                                     __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_sdp_media_hook);
 
 static int string_len(const struct nf_conn *ct, const char *dptr,
                      const char *limit, int *shift)
@@ -613,6 +634,26 @@ int ct_sip_get_sdp_header(const struct nf_conn *ct, const char *dptr,
 }
 EXPORT_SYMBOL_GPL(ct_sip_get_sdp_header);
 
+static int ct_sip_parse_sdp_addr(const struct nf_conn *ct, const char *dptr,
+                                unsigned int dataoff, unsigned int datalen,
+                                enum sdp_header_types type,
+                                enum sdp_header_types term,
+                                unsigned int *matchoff, unsigned int *matchlen,
+                                union nf_inet_addr *addr)
+{
+       int ret;
+
+       ret = ct_sip_get_sdp_header(ct, dptr, dataoff, datalen, type, term,
+                                   matchoff, matchlen);
+       if (ret <= 0)
+               return ret;
+
+       if (!parse_addr(ct, dptr + *matchoff, NULL, addr,
+                       dptr + *matchoff + *matchlen))
+               return -1;
+       return 1;
+}
+
 static int refresh_signalling_expectation(struct nf_conn *ct,
                                          union nf_inet_addr *addr,
                                          __be16 port,
@@ -663,7 +704,8 @@ static void flush_expectations(struct nf_conn *ct, bool media)
 
 static int set_expected_rtp_rtcp(struct sk_buff *skb,
                                 const char **dptr, unsigned int *datalen,
-                                union nf_inet_addr *daddr, __be16 port)
+                                union nf_inet_addr *daddr, __be16 port,
+                                unsigned int mediaoff, unsigned int medialen)
 {
        struct nf_conntrack_expect *exp, *rtp_exp, *rtcp_exp;
        enum ip_conntrack_info ctinfo;
@@ -675,7 +717,7 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
        int skip_expect = 0, ret = NF_DROP;
        u_int16_t base_port;
        __be16 rtp_port, rtcp_port;
-       typeof(nf_nat_sdp_hook) nf_nat_sdp;
+       typeof(nf_nat_sdp_media_hook) nf_nat_sdp_media;
 
        saddr = NULL;
        if (sip_direct_media) {
@@ -724,9 +766,10 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb,
        nf_ct_expect_init(rtcp_exp, SIP_EXPECT_AUDIO, family, saddr, daddr,
                          IPPROTO_UDP, NULL, &rtcp_port);
 
-       nf_nat_sdp = rcu_dereference(nf_nat_sdp_hook);
-       if (nf_nat_sdp && ct->status & IPS_NAT_MASK)
-               ret = nf_nat_sdp(skb, dptr, datalen, rtp_exp, rtcp_exp);
+       nf_nat_sdp_media = rcu_dereference(nf_nat_sdp_media_hook);
+       if (nf_nat_sdp_media && ct->status & IPS_NAT_MASK)
+               ret = nf_nat_sdp_media(skb, dptr, datalen, rtp_exp, rtcp_exp,
+                                      mediaoff, medialen, daddr);
        else {
                if (nf_ct_expect_related(rtp_exp) == 0) {
                        if (nf_ct_expect_related(rtcp_exp) != 0)
@@ -750,33 +793,78 @@ static int process_sdp(struct sk_buff *skb,
        struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
        int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
        unsigned int matchoff, matchlen;
-       union nf_inet_addr addr;
+       unsigned int mediaoff, medialen;
+       unsigned int sdpoff;
+       unsigned int caddr_len, maddr_len;
+       union nf_inet_addr caddr, maddr, rtp_addr;
        unsigned int port;
-       enum sdp_header_types type;
+       enum sdp_header_types c_hdr;
+       int ret;
+       typeof(nf_nat_sdp_addr_hook) nf_nat_sdp_addr;
+       typeof(nf_nat_sdp_session_hook) nf_nat_sdp_session;
 
-       /* Get address and port from SDP packet. */
-       type = family == AF_INET ? SDP_HDR_CONNECTION_IP4 :
-                                  SDP_HDR_CONNECTION_IP6;
+       c_hdr = family == AF_INET ? SDP_HDR_CONNECTION_IP4 :
+                                   SDP_HDR_CONNECTION_IP6;
 
+       /* Find beginning of session description */
        if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
-                                 type, SDP_HDR_UNSPEC,
+                                 SDP_HDR_VERSION, SDP_HDR_UNSPEC,
                                  &matchoff, &matchlen) <= 0)
                return NF_ACCEPT;
-
-       /* We'll drop only if there are parse problems. */
-       if (!parse_addr(ct, *dptr + matchoff, NULL, &addr, *dptr + *datalen))
-               return NF_DROP;
-
-       if (ct_sip_get_sdp_header(ct, *dptr, 0, *datalen,
+       sdpoff = matchoff;
+
+       /* The connection information is contained in the session description
+        * and/or once per media description. The first media description marks
+        * the end of the session description. */
+       caddr_len = 0;
+       if (ct_sip_parse_sdp_addr(ct, *dptr, sdpoff, *datalen,
+                                 c_hdr, SDP_HDR_MEDIA,
+                                 &matchoff, &matchlen, &caddr) > 0)
+               caddr_len = matchlen;
+
+       if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen,
                                  SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
-                                 &matchoff, &matchlen) <= 0)
+                                 &mediaoff, &medialen) <= 0)
                return NF_ACCEPT;
 
-       port = simple_strtoul(*dptr + matchoff, NULL, 10);
+       port = simple_strtoul(*dptr + mediaoff, NULL, 10);
        if (port < 1024 || port > 65535)
                return NF_DROP;
 
-       return set_expected_rtp_rtcp(skb, dptr, datalen, &addr, htons(port));
+       /* The media description overrides the session description. */
+       maddr_len = 0;
+       if (ct_sip_parse_sdp_addr(ct, *dptr, mediaoff, *datalen,
+                                 c_hdr, SDP_HDR_MEDIA,
+                                 &matchoff, &matchlen, &maddr) > 0) {
+               maddr_len = matchlen;
+               memcpy(&rtp_addr, &maddr, sizeof(rtp_addr));
+       } else if (caddr_len)
+               memcpy(&rtp_addr, &caddr, sizeof(rtp_addr));
+       else
+               return NF_DROP;
+
+       ret = set_expected_rtp_rtcp(skb, dptr, datalen, &rtp_addr, htons(port),
+                                   mediaoff, medialen);
+       if (ret != NF_ACCEPT)
+               return ret;
+
+       /* Update media connection address if present */
+       if (maddr_len) {
+               nf_nat_sdp_addr = rcu_dereference(nf_nat_sdp_addr_hook);
+               if (nf_nat_sdp_addr && ct->status & IPS_NAT_MASK) {
+                       ret = nf_nat_sdp_addr(skb, dptr, mediaoff, datalen,
+                                             c_hdr, SDP_HDR_MEDIA, &rtp_addr);
+                       if (ret != NF_ACCEPT)
+                               return ret;
+               }
+       }
+
+       /* Update session connection and owner addresses */
+       nf_nat_sdp_session = rcu_dereference(nf_nat_sdp_session_hook);
+       if (nf_nat_sdp_session && ct->status & IPS_NAT_MASK)
+               ret = nf_nat_sdp_session(skb, dptr, sdpoff, datalen, &rtp_addr);
+
+       return ret;
 }
 static int process_invite_response(struct sk_buff *skb,
                                   const char **dptr, unsigned int *datalen,