ECC ciphersuite support
Submitted by: Douglas Stebila <douglas.stebila@sun.com>
(Authors: Vipul Gupta and Sumit Gupta, Sun Microsystems Laboratories)
diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c
index 20d716f..d26790a 100644
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -108,11 +108,36 @@
* Hudson (tjh@cryptsoft.com).
*
*/
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ *
+ * Portions of the attached software ("Contribution") are developed by
+ * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
+ *
+ * The Contribution is licensed pursuant to the OpenSSL open source
+ * license provided above.
+ *
+ * In addition, Sun covenants to all licensees who provide a reciprocal
+ * covenant with respect to their own patents if any, not to sue under
+ * current and future patent claims necessarily infringed by the making,
+ * using, practicing, selling, offering for sale and/or otherwise
+ * disposing of the Contribution as delivered hereunder
+ * (or portions thereof), provided that such covenant shall not apply:
+ * 1) for code that a licensee deletes from the Contribution;
+ * 2) separates from the Contribution; or
+ * 3) for infringements caused by:
+ * i) the modification of the Contribution or
+ * ii) the combination of the Contribution with other software or
+ * devices where such combination causes the infringement.
+ *
+ * ECC cipher suite support in OpenSSL originally written by
+ * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
+ *
+ */
#define REUSE_CIPHER_BUG
#define NETSCAPE_HANG_BUG
-
#include <stdio.h>
#include "ssl_locl.h"
#include "kssl_lcl.h"
@@ -137,6 +162,10 @@
static int ssl3_get_cert_verify(SSL *s);
static int ssl3_send_hello_request(SSL *s);
+#ifndef OPENSSL_NO_ECDH
+static int nid2curve_id(int nid);
+#endif
+
static SSL_METHOD *ssl3_get_server_method(int ver)
{
if (ver == SSL3_VERSION)
@@ -300,7 +329,7 @@
case SSL3_ST_SW_CERT_A:
case SSL3_ST_SW_CERT_B:
- /* Check if it is anon DH */
+ /* Check if it is anon DH or anon ECDH */
if (!(s->s3->tmp.new_cipher->algorithms & SSL_aNULL))
{
ret=ssl3_send_server_certificate(s);
@@ -331,9 +360,18 @@
else
s->s3->tmp.use_rsa_tmp=0;
+
/* only send if a DH key exchange, fortezza or
- * RSA but we have a sign only certificate */
+ * RSA but we have a sign only certificate
+ *
+ * For ECC ciphersuites, we send a serverKeyExchange
+ * message only if the cipher suite is either
+ * ECDH-anon or ECDHE. In other cases, the
+ * server certificate contains the server's
+ * public key for key exchange.
+ */
if (s->s3->tmp.use_rsa_tmp
+ || (l & SSL_kECDHE)
|| (l & (SSL_DH|SSL_kFZA))
|| ((l & SSL_kRSA)
&& (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
@@ -436,19 +474,33 @@
case SSL3_ST_SR_KEY_EXCH_A:
case SSL3_ST_SR_KEY_EXCH_B:
ret=ssl3_get_client_key_exchange(s);
- if (ret <= 0) goto end;
- s->state=SSL3_ST_SR_CERT_VRFY_A;
- s->init_num=0;
+ if (ret <= 0)
+ goto end;
+ if (ret == 2)
+ {
+ /* For the ECDH ciphersuites when
+ * the client sends its ECDH pub key in
+ * a certificate, the CertificateVerify
+ * message is not sent.
+ */
+ s->state=SSL3_ST_SR_FINISHED_A;
+ s->init_num = 0;
+ }
+ else
+ {
+ s->state=SSL3_ST_SR_CERT_VRFY_A;
+ s->init_num=0;
- /* We need to get hashes here so if there is
- * a client cert, it can be verified */
- s->method->ssl3_enc->cert_verify_mac(s,
- &(s->s3->finish_dgst1),
- &(s->s3->tmp.cert_verify_md[0]));
- s->method->ssl3_enc->cert_verify_mac(s,
- &(s->s3->finish_dgst2),
- &(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]));
-
+ /* We need to get hashes here so if there is
+ * a client cert, it can be verified
+ */
+ s->method->ssl3_enc->cert_verify_mac(s,
+ &(s->s3->finish_dgst1),
+ &(s->s3->tmp.cert_verify_md[0]));
+ s->method->ssl3_enc->cert_verify_mac(s,
+ &(s->s3->finish_dgst2),
+ &(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]));
+ }
break;
case SSL3_ST_SR_CERT_VRFY_A:
@@ -1036,6 +1088,13 @@
#ifndef OPENSSL_NO_DH
DH *dh=NULL,*dhp;
#endif
+#ifndef OPENSSL_NO_ECDH
+ EC_KEY *ecdh=NULL, *ecdhp;
+ unsigned char *encodedPoint = NULL;
+ int encodedlen = 0;
+ int curve_id = 0;
+ BN_CTX *bn_ctx = NULL;
+#endif
EVP_PKEY *pkey;
unsigned char *p,*d;
int al,i;
@@ -1144,6 +1203,131 @@
}
else
#endif
+#ifndef OPENSSL_NO_ECDH
+ if (type & SSL_kECDHE)
+ {
+ ecdhp=cert->ecdh_tmp;
+ if ((ecdhp == NULL) && (s->cert->ecdh_tmp_cb != NULL))
+ {
+ ecdhp=s->cert->ecdh_tmp_cb(s,
+ SSL_C_IS_EXPORT(s->s3->tmp.new_cipher),
+ SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher));
+ }
+ if (ecdhp == NULL)
+ {
+ al=SSL_AD_HANDSHAKE_FAILURE;
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,SSL_R_MISSING_TMP_ECDH_KEY);
+ goto f_err;
+ }
+
+ if (s->s3->tmp.ecdh != NULL)
+ {
+ EC_KEY_free(s->s3->tmp.ecdh);
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ /* Duplicate the ECDH structure. */
+ if (ecdhp == NULL)
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_ECDH_LIB);
+ goto err;
+ }
+ if (!EC_KEY_up_ref(ecdhp))
+ {
+ SSLerr(SSL_F_SSL3_CTRL,ERR_R_ECDH_LIB);
+ goto err;
+ }
+ ecdh = ecdhp;
+
+ s->s3->tmp.ecdh=ecdh;
+ if ((ecdh->pub_key == NULL) ||
+ (ecdh->priv_key == NULL) ||
+ (s->options & SSL_OP_SINGLE_ECDH_USE))
+ {
+ if(!EC_KEY_generate_key(ecdh))
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_ECDH_LIB);
+ goto err;
+ }
+ }
+
+ if ((ecdh->group == NULL) ||
+ (ecdh->pub_key == NULL) ||
+ (ecdh->priv_key == NULL))
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_ECDH_LIB);
+ goto err;
+ }
+
+ if (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) &&
+ (EC_GROUP_get_degree(ecdh->group) > 163))
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,SSL_R_ECGROUP_TOO_LARGE_FOR_CIPHER);
+ goto err;
+ }
+
+ /* XXX: For now, we only support ephemeral ECDH
+ * keys over named (not generic) curves. For
+ * supported named curves, curve_id is non-zero.
+ */
+ if ((curve_id =
+ nid2curve_id(EC_GROUP_get_nid(ecdh->group)))
+ == 0)
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
+ goto err;
+ }
+
+ /* Encode the public key.
+ * First check the size of encoding and
+ * allocate memory accordingly.
+ */
+ encodedlen = EC_POINT_point2oct(ecdh->group,
+ ecdh->pub_key,
+ POINT_CONVERSION_UNCOMPRESSED,
+ NULL, 0, NULL);
+
+ encodedPoint = (unsigned char *)
+ OPENSSL_malloc(encodedlen*sizeof(unsigned char));
+ bn_ctx = BN_CTX_new();
+ if ((encodedPoint == NULL) || (bn_ctx == NULL))
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+
+ encodedlen = EC_POINT_point2oct(ecdh->group,
+ ecdh->pub_key,
+ POINT_CONVERSION_UNCOMPRESSED,
+ encodedPoint, encodedlen, bn_ctx);
+
+ if (encodedlen == 0)
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_ECDH_LIB);
+ goto err;
+ }
+
+ BN_CTX_free(bn_ctx); bn_ctx=NULL;
+
+ /* XXX: For now, we only support named (not
+ * generic) curves in ECDH ephemeral key exchanges.
+ * In this situation, we need three additional bytes
+ * to encode the entire ServerECDHParams
+ * structure.
+ */
+ n = 3 + encodedlen;
+
+ /* We'll generate the serverKeyExchange message
+ * explicitly so we can set these to NULLs
+ */
+ r[0]=NULL;
+ r[1]=NULL;
+ r[2]=NULL;
+ }
+ else
+#endif /* !OPENSSL_NO_ECDH */
{
al=SSL_AD_HANDSHAKE_FAILURE;
SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
@@ -1186,6 +1370,29 @@
p+=nr[i];
}
+#ifndef OPENSSL_NO_ECDH
+ if (type & SSL_kECDHE)
+ {
+ /* XXX: For now, we only support named (not generic) curves.
+ * In this situation, the serverKeyExchange message has:
+ * [1 byte CurveType], [1 byte CurveName]
+ * [1 byte length of encoded point], followed by
+ * the actual encoded point itself
+ */
+ *p = NAMED_CURVE_TYPE;
+ p += 1;
+ *p = curve_id;
+ p += 1;
+ *p = encodedlen;
+ p += 1;
+ memcpy((unsigned char*)p,
+ (unsigned char *)encodedPoint,
+ encodedlen);
+ OPENSSL_free(encodedPoint);
+ p += encodedlen;
+ }
+#endif
+
/* not anonymous */
if (pkey != NULL)
{
@@ -1238,6 +1445,25 @@
}
else
#endif
+#if !defined(OPENSSL_NO_ECDSA)
+ if (pkey->type == EVP_PKEY_ECDSA)
+ {
+ /* let's do ECDSA */
+ EVP_SignInit_ex(&md_ctx,EVP_ecdsa(), NULL);
+ EVP_SignUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE);
+ EVP_SignUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE);
+ EVP_SignUpdate(&md_ctx,&(d[4]),n);
+ if (!EVP_SignFinal(&md_ctx,&(p[2]),
+ (unsigned int *)&i,pkey))
+ {
+ SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_LIB_ECDSA);
+ goto err;
+ }
+ s2n(i,p);
+ n+=i+2;
+ }
+ else
+#endif
{
/* Is this error check actually needed? */
al=SSL_AD_HANDSHAKE_FAILURE;
@@ -1261,6 +1487,10 @@
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
+#ifndef OPENSSL_NO_ECDH
+ if (encodedPoint != NULL) OPENSSL_free(encodedPoint);
+ BN_CTX_free(bn_ctx);
+#endif
EVP_MD_CTX_cleanup(&md_ctx);
return(-1);
}
@@ -1371,6 +1601,13 @@
KSSL_ERR kssl_err;
#endif /* OPENSSL_NO_KRB5 */
+#ifndef OPENSSL_NO_ECDH
+ EC_KEY *srvr_ecdh = NULL;
+ EVP_PKEY *clnt_pub_pkey = NULL;
+ EC_POINT *clnt_ecpoint = NULL;
+ BN_CTX *bn_ctx = NULL;
+#endif
+
n=ssl3_get_message(s,
SSL3_ST_SR_KEY_EXCH_A,
SSL3_ST_SR_KEY_EXCH_B,
@@ -1711,6 +1948,138 @@
}
else
#endif /* OPENSSL_NO_KRB5 */
+
+#ifndef OPENSSL_NO_ECDH
+ if ((l & SSL_kECDH) || (l & SSL_kECDHE))
+ {
+ int ret = 1;
+
+ /* initialize structures for server's ECDH key pair */
+ if ((srvr_ecdh = EC_KEY_new()) == NULL)
+ {
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ /* Let's get server private key and group information */
+ if (l & SSL_kECDH)
+ {
+ /* use the certificate */
+ srvr_ecdh->group = s->cert->key->privatekey-> \
+ pkey.eckey->group;
+ srvr_ecdh->priv_key = s->cert->key->privatekey-> \
+ pkey.eckey->priv_key;
+ }
+ else
+ {
+ /* use the ephermeral values we saved when
+ * generating the ServerKeyExchange msg.
+ */
+ srvr_ecdh->group = s->s3->tmp.ecdh->group;
+ srvr_ecdh->priv_key = s->s3->tmp.ecdh->priv_key;
+ }
+
+ /* Let's get client's public key */
+ if ((clnt_ecpoint = EC_POINT_new(srvr_ecdh->group))
+ == NULL)
+ {
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ if (n == 0L)
+ {
+ /* Client Publickey was in Client Certificate */
+
+ if (l & SSL_kECDHE)
+ {
+ al=SSL_AD_HANDSHAKE_FAILURE;
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_MISSING_TMP_ECDH_KEY);
+ goto f_err;
+ }
+ if (((clnt_pub_pkey=X509_get_pubkey(s->session->peer))
+ == NULL) ||
+ (clnt_pub_pkey->type != EVP_PKEY_ECDSA))
+ {
+ /* XXX: For now, we do not support client
+ * authentication using ECDH certificates
+ * so this branch (n == 0L) of the code is
+ * never executed. When that support is
+ * added, we ought to ensure the key
+ * received in the certificate is
+ * authorized for key agreement.
+ * ECDH_compute_key implicitly checks that
+ * the two ECDH shares are for the same
+ * group.
+ */
+ al=SSL_AD_HANDSHAKE_FAILURE;
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ SSL_R_UNABLE_TO_DECODE_ECDH_CERTS);
+ goto f_err;
+ }
+
+ EC_POINT_copy(clnt_ecpoint,
+ clnt_pub_pkey->pkey.eckey->pub_key);
+ ret = 2; /* Skip certificate verify processing */
+ }
+ else
+ {
+ /* Get client's public key from encoded point
+ * in the ClientKeyExchange message.
+ */
+ if ((bn_ctx = BN_CTX_new()) == NULL)
+ {
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ /* Get encoded point length */
+ i = *p;
+ p += 1;
+ if (EC_POINT_oct2point(srvr_ecdh->group,
+ clnt_ecpoint, p, i, bn_ctx) == 0)
+ {
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ ERR_R_EC_LIB);
+ goto err;
+ }
+ /* p is pointing to somewhere in the buffer
+ * currently, so set it to the start
+ */
+ p=(unsigned char *)s->init_buf->data;
+ }
+
+ /* Compute the shared pre-master secret */
+ i = ECDH_compute_key(p, clnt_ecpoint, srvr_ecdh);
+ if (i <= 0)
+ {
+ SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
+ ERR_R_ECDH_LIB);
+ goto err;
+ }
+
+ EVP_PKEY_free(clnt_pub_pkey);
+ EC_POINT_free(clnt_ecpoint);
+ if (srvr_ecdh != NULL)
+ {
+ srvr_ecdh->priv_key = NULL;
+ srvr_ecdh->group = NULL;
+ EC_KEY_free(srvr_ecdh);
+ }
+ BN_CTX_free(bn_ctx);
+
+ /* Compute the master secret */
+ s->session->master_key_length = s->method->ssl3_enc-> \
+ generate_master_secret(s, s->session->master_key, p, i);
+
+ memset(p, 0, i);
+ return (ret);
+ }
+ else
+#endif
{
al=SSL_AD_HANDSHAKE_FAILURE;
SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
@@ -1721,9 +2090,20 @@
return(1);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
-#if !defined(OPENSSL_NO_DH) || !defined(OPENSSL_NO_RSA)
+#if !defined(OPENSSL_NO_DH) || !defined(OPENSSL_NO_RSA) || !defined(OPENSSL_NO_ECDH)
err:
#endif
+#ifndef NO_OPENSSL_ECDH
+ EVP_PKEY_free(clnt_pub_pkey);
+ EC_POINT_free(clnt_ecpoint);
+ if (srvr_ecdh != NULL)
+ {
+ srvr_ecdh->priv_key = NULL;
+ srvr_ecdh->group = NULL;
+ EC_KEY_free(srvr_ecdh);
+ }
+ BN_CTX_free(bn_ctx);
+#endif
return(-1);
}
@@ -1847,6 +2227,23 @@
}
else
#endif
+#ifndef OPENSSL_NO_ECDSA
+ if (pkey->type == EVP_PKEY_ECDSA)
+ {
+ j=ECDSA_verify(pkey->save_type,
+ &(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
+ SHA_DIGEST_LENGTH,p,i,pkey->pkey.eckey);
+ if (j <= 0)
+ {
+ /* bad signature */
+ al=SSL_AD_DECRYPT_ERROR;
+ SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,
+ SSL_R_BAD_ECDSA_SIGNATURE);
+ goto f_err;
+ }
+ }
+ else
+#endif
{
SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,ERR_R_INTERNAL_ERROR);
al=SSL_AD_UNSUPPORTED_CERTIFICATE;
@@ -2047,3 +2444,66 @@
/* SSL3_ST_SW_CERT_B */
return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
}
+
+
+#ifndef OPENSSL_NO_ECDH
+/* This is the complement of curve_id2nid in s3_clnt.c. */
+static int nid2curve_id(int nid)
+{
+ /* ECC curves from draft-ietf-tls-ecc-01.txt (Mar 15, 2001) */
+ switch (nid) {
+ case NID_sect163k1: /* sect163k1 (1) */
+ return 1;
+ case NID_sect163r1: /* sect163r1 (2) */
+ return 2;
+ case NID_sect163r2: /* sect163r2 (3) */
+ return 3;
+ case NID_sect193r1: /* sect193r1 (4) */
+ return 4;
+ case NID_sect193r2: /* sect193r2 (5) */
+ return 5;
+ case NID_sect233k1: /* sect233k1 (6) */
+ return 6;
+ case NID_sect233r1: /* sect233r1 (7) */
+ return 7;
+ case NID_sect239k1: /* sect239k1 (8) */
+ return 8;
+ case NID_sect283k1: /* sect283k1 (9) */
+ return 9;
+ case NID_sect283r1: /* sect283r1 (10) */
+ return 10;
+ case NID_sect409k1: /* sect409k1 (11) */
+ return 11;
+ case NID_sect409r1: /* sect409r1 (12) */
+ return 12;
+ case NID_sect571k1: /* sect571k1 (13) */
+ return 13;
+ case NID_sect571r1: /* sect571r1 (14) */
+ return 14;
+ case NID_secp160k1: /* secp160k1 (15) */
+ return 15;
+ case NID_secp160r1: /* secp160r1 (16) */
+ return 16;
+ case NID_secp160r2: /* secp160r2 (17) */
+ return 17;
+ case NID_secp192k1: /* secp192k1 (18) */
+ return 18;
+ case NID_X9_62_prime192v1: /* secp192r1 (19) */
+ return 19;
+ case NID_secp224k1: /* secp224k1 (20) */
+ return 20;
+ case NID_secp224r1: /* secp224r1 (21) */
+ return 21;
+ case NID_secp256k1: /* secp256k1 (22) */
+ return 22;
+ case NID_X9_62_prime256v1: /* secp256r1 (23) */
+ return 23;
+ case NID_secp384r1: /* secp384r1 (24) */
+ return 24;
+ case NID_secp521r1: /* secp521r1 (25) */
+ return 25;
+ default:
+ return 0;
+ }
+}
+#endif
