updates for draft-ietf-tls-ecc-03.txt
Submitted by: Douglas Stebila
Reviewed by: Bodo Moeller
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 211dd03..7eff4f1 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -1870,6 +1870,7 @@
{
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 @@
* 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 @@
/* 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,
