+
+#ifndef OPENSSL_NO_TLSEXT
+unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
+ {
+ int extdatalen=0;
+ unsigned char *ret = p;
+
+ ret+=2;
+
+ if (ret>=limit) return NULL; /* this really never occurs, but ... */
+ if (s->tlsext_hostname != NULL)
+ {
+ /* Add TLS extension servername to the Client Hello message */
+ unsigned long size_str;
+ long lenmax;
+
+ /* check for enough space.
+ 4 for the servername type and entension length
+ 2 for servernamelist length
+ 1 for the hostname type
+ 2 for hostname length
+ + hostname length
+ */
+
+ if ((lenmax = limit - p - 9) < 0
+ || (size_str = strlen(s->tlsext_hostname)) > (unsigned long)lenmax)
+ return NULL;
+
+ /* extension type and length */
+ s2n(TLSEXT_TYPE_server_name,ret);
+ s2n(size_str+5,ret);
+
+ /* length of servername list */
+ s2n(size_str+3,ret);
+
+ /* hostname type, length and hostname */
+ *(ret++) = (unsigned char) TLSEXT_NAMETYPE_host_name;
+ s2n(size_str,ret);
+ memcpy(ret, s->tlsext_hostname, size_str);
+ ret+=size_str;
+
+ }
+#ifndef OPENSSL_NO_EC
+ if (s->tlsext_ecpointformatlist != NULL)
+ {
+ /* Add TLS extension ECPointFormats to the ClientHello message */
+ long lenmax;
+
+ if ((lenmax = limit - p - 5) < 0) return NULL;
+ if (s->tlsext_ecpointformatlist_length > (unsigned long)lenmax) return NULL;
+ if (s->tlsext_ecpointformatlist_length > 255)
+ {
+ SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+ return NULL;
+ }
+
+ s2n(TLSEXT_TYPE_ec_point_formats,ret);
+ s2n(s->tlsext_ecpointformatlist_length + 1,ret);
+ *(ret++) = (unsigned char) s->tlsext_ecpointformatlist_length;
+ memcpy(ret, s->tlsext_ecpointformatlist, s->tlsext_ecpointformatlist_length);
+ ret+=s->tlsext_ecpointformatlist_length;
+ }
+ if (s->tlsext_ellipticcurvelist != NULL)
+ {
+ /* Add TLS extension EllipticCurves to the ClientHello message */
+ long lenmax;
+
+ if ((lenmax = limit - p - 6) < 0) return NULL;
+ if (s->tlsext_ellipticcurvelist_length > (unsigned long)lenmax) return NULL;
+ if (s->tlsext_ellipticcurvelist_length > 65532)
+ {
+ SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+ return NULL;
+ }
+
+ s2n(TLSEXT_TYPE_elliptic_curves,ret);
+ s2n(s->tlsext_ellipticcurvelist_length + 2, ret);
+
+ /* NB: draft-ietf-tls-ecc-12.txt uses a one-byte prefix for
+ * elliptic_curve_list, but the examples use two bytes.
+ * http://www1.ietf.org/mail-archive/web/tls/current/msg00538.html
+ * resolves this to two bytes.
+ */
+ s2n(s->tlsext_ellipticcurvelist_length, ret);
+ memcpy(ret, s->tlsext_ellipticcurvelist, s->tlsext_ellipticcurvelist_length);
+ ret+=s->tlsext_ellipticcurvelist_length;
+ }
+#endif /* OPENSSL_NO_EC */
+
+ if ((extdatalen = ret-p-2)== 0)
+ return p;
+
+ s2n(extdatalen,p);
+ return ret;
+}
+
+unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
+ {
+ int extdatalen=0;
+ unsigned char *ret = p;
+
+ ret+=2;
+ if (ret>=limit) return NULL; /* this really never occurs, but ... */
+
+ if (!s->hit && s->servername_done == 1 && s->session->tlsext_hostname != NULL)
+ {
+ if (limit - p - 4 < 0) return NULL;
+
+ s2n(TLSEXT_TYPE_server_name,ret);
+ s2n(0,ret);
+ }
+#ifndef OPENSSL_NO_EC
+ if (s->tlsext_ecpointformatlist != NULL)
+ {
+ /* Add TLS extension ECPointFormats to the ServerHello message */
+ long lenmax;
+
+ if ((lenmax = limit - p - 5) < 0) return NULL;
+ if (s->tlsext_ecpointformatlist_length > (unsigned long)lenmax) return NULL;
+ if (s->tlsext_ecpointformatlist_length > 255)
+ {
+ SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
+ return NULL;
+ }
+
+ s2n(TLSEXT_TYPE_ec_point_formats,ret);
+ s2n(s->tlsext_ecpointformatlist_length + 1,ret);
+ *(ret++) = (unsigned char) s->tlsext_ecpointformatlist_length;
+ memcpy(ret, s->tlsext_ecpointformatlist, s->tlsext_ecpointformatlist_length);
+ ret+=s->tlsext_ecpointformatlist_length;
+
+ }
+ /* Currently the server should not respond with a SupportedCurves extension */
+#endif /* OPENSSL_NO_EC */
+
+ if ((extdatalen = ret-p-2)== 0)
+ return p;
+
+ s2n(extdatalen,p);
+ return ret;
+}
+
+int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, int n, int *al)
+ {
+ unsigned short type;
+ unsigned short size;
+ unsigned short len;
+ unsigned char *data = *p;
+ s->servername_done = 0;
+
+ if (data >= (d+n-2))
+ return 1;
+ n2s(data,len);
+
+ if (data > (d+n-len))
+ return 1;
+
+ while (data <= (d+n-4))
+ {
+ n2s(data,type);
+ n2s(data,size);
+
+ if (data+size > (d+n))
+ return 1;
+
+/* The servername extension is treated as follows:
+
+ - Only the hostname type is supported with a maximum length of 255.
+ - The servername is rejected if too long or if it contains zeros,
+ in which case an fatal alert is generated.
+ - The servername field is maintained together with the session cache.
+ - When a session is resumed, the servername call back invoked in order
+ to allow the application to position itself to the right context.
+ - The servername is acknowledged if it is new for a session or when
+ it is identical to a previously used for the same session.
+ Applications can control the behaviour. They can at any time
+ set a 'desirable' servername for a new SSL object. This can be the
+ case for example with HTTPS when a Host: header field is received and
+ a renegotiation is requested. In this case, a possible servername
+ presented in the new client hello is only acknowledged if it matches
+ the value of the Host: field.
+ - Applications must use SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
+ if they provide for changing an explicit servername context for the session,
+ i.e. when the session has been established with a servername extension.
+ - On session reconnect, the servername extension may be absent.
+
+*/
+
+ if (type == TLSEXT_TYPE_server_name)
+ {
+ unsigned char *sdata;
+ int servname_type;
+ int dsize;
+
+ if (size < 2)
+ {
+ *al = SSL_AD_DECODE_ERROR;
+ return 0;
+ }
+ n2s(data,dsize);
+ size -= 2;
+ if (dsize > size )
+ {
+ *al = SSL_AD_DECODE_ERROR;
+ return 0;
+ }
+
+ sdata = data;
+ while (dsize > 3)
+ {
+ servname_type = *(sdata++);
+ n2s(sdata,len);
+ dsize -= 3;
+
+ if (len > dsize)
+ {
+ *al = SSL_AD_DECODE_ERROR;
+ return 0;
+ }
+ if (s->servername_done == 0)
+ switch (servname_type)
+ {
+ case TLSEXT_NAMETYPE_host_name:
+ if (s->session->tlsext_hostname == NULL)
+ {
+ if (len > TLSEXT_MAXLEN_host_name ||
+ ((s->session->tlsext_hostname = OPENSSL_malloc(len+1)) == NULL))
+ {
+ *al = TLS1_AD_UNRECOGNIZED_NAME;
+ return 0;
+ }
+ memcpy(s->session->tlsext_hostname, sdata, len);
+ s->session->tlsext_hostname[len]='\0';
+ if (strlen(s->session->tlsext_hostname) != len) {
+ OPENSSL_free(s->session->tlsext_hostname);
+ *al = TLS1_AD_UNRECOGNIZED_NAME;
+ return 0;
+ }
+ s->servername_done = 1;
+
+ }
+ else
+ s->servername_done = strlen(s->session->tlsext_hostname) == len
+ && strncmp(s->session->tlsext_hostname, (char *)sdata, len) == 0;
+
+ break;
+
+ default:
+ break;
+ }
+
+ dsize -= len;
+ }
+ if (dsize != 0)
+ {
+ *al = SSL_AD_DECODE_ERROR;
+ return 0;
+ }
+
+ }
+
+#ifndef OPENSSL_NO_EC
+ else if (type == TLSEXT_TYPE_ec_point_formats)
+ {
+ unsigned char *sdata = data;
+ int ecpointformatlist_length = *(sdata++);
+
+ if (ecpointformatlist_length != size - 1)
+ {
+ *al = TLS1_AD_DECODE_ERROR;
+ return 0;
+ }
+ s->session->tlsext_ecpointformatlist_length = 0;
+ if (s->session->tlsext_ecpointformatlist != NULL) OPENSSL_free(s->session->tlsext_ecpointformatlist);
+ if ((s->session->tlsext_ecpointformatlist = OPENSSL_malloc(ecpointformatlist_length)) == NULL)
+ {
+ *al = TLS1_AD_INTERNAL_ERROR;
+ return 0;
+ }
+ s->session->tlsext_ecpointformatlist_length = ecpointformatlist_length;
+ memcpy(s->session->tlsext_ecpointformatlist, sdata, ecpointformatlist_length);
+#if 0
+ fprintf(stderr,"ssl_parse_clienthello_tlsext s->session->tlsext_ecpointformatlist (length=%i) ", s->session->tlsext_ecpointformatlist_length);
+ sdata = s->session->tlsext_ecpointformatlist;
+ for (i = 0; i < s->session->tlsext_ecpointformatlist_length; i++)
+ fprintf(stderr,"%i ",*(sdata++));
+ fprintf(stderr,"\n");
+#endif
+ }
+ else if (type == TLSEXT_TYPE_elliptic_curves)
+ {
+ unsigned char *sdata = data;
+ int ellipticcurvelist_length = (*(sdata++) << 8);
+ ellipticcurvelist_length += (*(sdata++));
+
+ if (ellipticcurvelist_length != size - 2)
+ {
+ *al = TLS1_AD_DECODE_ERROR;
+ return 0;
+ }
+ s->session->tlsext_ellipticcurvelist_length = 0;
+ if (s->session->tlsext_ellipticcurvelist != NULL) OPENSSL_free(s->session->tlsext_ellipticcurvelist);
+ if ((s->session->tlsext_ellipticcurvelist = OPENSSL_malloc(ellipticcurvelist_length)) == NULL)
+ {
+ *al = TLS1_AD_INTERNAL_ERROR;
+ return 0;
+ }
+ s->session->tlsext_ellipticcurvelist_length = ellipticcurvelist_length;
+ memcpy(s->session->tlsext_ellipticcurvelist, sdata, ellipticcurvelist_length);