updates for draft-ietf-tls-ecc-03.txt

[openssl.git] / ssl / s3_clnt.c

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 211dd03b110bd0ae491403ec8f841f94d5be85d4..7eff4f1d5ef1eb696874d5148d24a5378bb33548 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -1870,6 +1870,7 @@ static int ssl3_send_client_key_exchange(SSL *s)
                        {
                        EC_GROUP *srvr_group = NULL;
                        int ecdh_clnt_cert = 0;
+                       int field_size = 0;
 
                        /* Did we send out the client's
                         * ECDH share for use in premaster
@@ -1962,7 +1963,21 @@ static int ssl3_send_client_key_exchange(SSL *s)
                         * make sure to clear it out afterwards
                         */
 
-                       n=ECDH_compute_key(p, KDF1_SHA1_len, srvr_ecpoint, clnt_ecdh, KDF1_SHA1);
+                       field_size = EC_GROUP_get_degree(clnt_ecdh->group);
+                       if (field_size <= 0)
+                               {
+                               SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, 
+                                      ERR_R_ECDH_LIB);
+                               goto err;
+                               }
+                       /* If field size is not more than 24 octets, then use SHA-1 hash of result;
+                        * otherwise, use result (see section 4.8 of draft-ietf-tls-ecc-03.txt;
+                        * this is new with this version of the Internet Draft).
+                        */
+                       if (field_size <= 24 * 8)
+                               n=ECDH_compute_key(p, KDF1_SHA1_len, srvr_ecpoint, clnt_ecdh, KDF1_SHA1);
+                       else
+                               n=ECDH_compute_key(p, (field_size+7)/8, srvr_ecpoint, clnt_ecdh, NULL);
                        if (n <= 0)
                                {
                                SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, 
@@ -2375,7 +2390,8 @@ err:
 /* This is the complement of nid2curve_id in s3_srvr.c. */
 static int curve_id2nid(int curve_id)
 {
-       /* ECC curves from draft-ietf-tls-ecc-01.txt (Mar 15, 2001) */
+       /* ECC curves from draft-ietf-tls-ecc-01.txt (Mar 15, 2001)
+        * (no changes in draft-ietf-tls-ecc-03.txt [June 2003]) */
        static int nid_list[26] =
        {
                0,