+/*
+ * Note: this function returns 0 length if there are no profiles specified
+ */
+int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
+ int maxlen)
+{
+ int ct = 0;
+ int i;
+ STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = 0;
+ SRTP_PROTECTION_PROFILE *prof;
+
+ clnt = SSL_get_srtp_profiles(s);
+ ct = sk_SRTP_PROTECTION_PROFILE_num(clnt); /* -1 if clnt == 0 */
+
+ if (p) {
+ if (ct == 0) {
+ SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST);
+ return 1;
+ }
+
+ if ((2 + ct * 2 + 1) > maxlen) {
+ SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
+ return 1;
+ }
+
+ /* Add the length */
+ s2n(ct * 2, p);
+ for (i = 0; i < ct; i++) {
+ prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
+ s2n(prof->id, p);
+ }
+
+ /* Add an empty use_mki value */
+ *p++ = 0;
+ }
+
+ *len = 2 + ct * 2 + 1;
+
+ return 0;
+}
+
+int ssl_parse_clienthello_use_srtp_ext(SSL *s, PACKET *pkt, int *al)
+{
+ SRTP_PROTECTION_PROFILE *sprof;
+ STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
+ unsigned int ct, mki_len, id;
+ int i, srtp_pref;
+ PACKET subpkt;
+
+ /* Pull off the length of the cipher suite list and check it is even */
+ if (!PACKET_get_net_2(pkt, &ct)
+ || (ct & 1) != 0 || !PACKET_get_sub_packet(pkt, &subpkt, ct)) {
+ SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ srvr = SSL_get_srtp_profiles(s);
+ s->srtp_profile = NULL;
+ /* Search all profiles for a match initially */
+ srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr);
+
+ while (PACKET_remaining(&subpkt)) {
+ if (!PACKET_get_net_2(&subpkt, &id)) {
+ SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ /*
+ * Only look for match in profiles of higher preference than
+ * current match.
+ * If no profiles have been have been configured then this
+ * does nothing.
+ */
+ for (i = 0; i < srtp_pref; i++) {
+ sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
+ if (sprof->id == id) {
+ s->srtp_profile = sprof;
+ srtp_pref = i;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Now extract the MKI value as a sanity check, but discard it for now
+ */
+ if (!PACKET_get_1(pkt, &mki_len)) {
+ SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ if (!PACKET_forward(pkt, mki_len)
+ || PACKET_remaining(pkt)) {
+ SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_MKI_VALUE);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ return 0;
+}
+
+int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
+ int maxlen)
+{
+ if (p) {
+ if (maxlen < 5) {
+ SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
+ return 1;
+ }
+
+ if (s->srtp_profile == 0) {
+ SSLerr(SSL_F_SSL_ADD_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_USE_SRTP_NOT_NEGOTIATED);
+ return 1;
+ }
+ s2n(2, p);
+ s2n(s->srtp_profile->id, p);
+ *p++ = 0;
+ }
+ *len = 5;
+
+ return 0;
+}
+
+int ssl_parse_serverhello_use_srtp_ext(SSL *s, PACKET *pkt, int *al)
+{
+ unsigned int id, ct, mki;
+ int i;
+
+ STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
+ SRTP_PROTECTION_PROFILE *prof;
+
+ if (!PACKET_get_net_2(pkt, &ct)
+ || ct != 2 || !PACKET_get_net_2(pkt, &id)
+ || !PACKET_get_1(pkt, &mki)
+ || PACKET_remaining(pkt) != 0) {
+ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ if (mki != 0) {
+ /* Must be no MKI, since we never offer one */
+ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_MKI_VALUE);
+ *al = SSL_AD_ILLEGAL_PARAMETER;
+ return 1;
+ }
+
+ clnt = SSL_get_srtp_profiles(s);
+
+ /* Throw an error if the server gave us an unsolicited extension */
+ if (clnt == NULL) {
+ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_NO_SRTP_PROFILES);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+ }
+
+ /*
+ * Check to see if the server gave us something we support (and
+ * presumably offered)
+ */
+ for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
+ prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
+
+ if (prof->id == id) {
+ s->srtp_profile = prof;
+ *al = 0;
+ return 0;
+ }
+ }
+
+ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
+ SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *al = SSL_AD_DECODE_ERROR;
+ return 1;
+}