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_clnt.c b/ssl/s3_clnt.c index 2b58482..74e1e52 100644 --- a/ssl/s3_clnt.c +++ b/ssl/s3_clnt.c
@@ -108,6 +108,32 @@ * 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. + * + */ #include <stdio.h> #include "ssl_locl.h" @@ -131,6 +157,12 @@ static int ssl3_get_key_exchange(SSL *s); static int ssl3_get_server_certificate(SSL *s); static int ssl3_check_cert_and_algorithm(SSL *s); + +#ifndef OPENSSL_NO_ECDH +static int curve_id2nid(int curve_id); +int check_srvr_ecc_cert_and_alg(X509 *x, SSL_CIPHER *cs); +#endif + static SSL_METHOD *ssl3_get_client_method(int ver) { if (ver == SSL3_VERSION) @@ -262,7 +294,7 @@ case SSL3_ST_CR_CERT_A: case SSL3_ST_CR_CERT_B: - /* Check if it is anon DH */ + /* Check if it is anon DH/ECDH */ if (!(s->s3->tmp.new_cipher->algorithms & SSL_aNULL)) { ret=ssl3_get_server_certificate(s); @@ -329,6 +361,13 @@ * sent back */ /* For TLS, cert_req is set to 2, so a cert chain * of nothing is sent, but no verify packet is sent */ + /* XXX: For now, we do not support client + * authentication in ECDH cipher suites with + * ECDH (rather than ECDSA) certificates. + * We need to skip the certificate verify + * message when client's ECDH public key is sent + * inside the client certificate. + */ if (s->s3->tmp.cert_req == 1) { s->state=SSL3_ST_CW_CERT_VRFY_A; @@ -944,6 +983,13 @@ #ifndef OPENSSL_NO_DH DH *dh=NULL; #endif +#ifndef OPENSSL_NO_ECDH + EC_KEY *ecdh = NULL; + BN_CTX *bn_ctx = NULL; + EC_POINT *srvr_ecpoint = NULL; + int curve_nid = 0; + int encoded_pt_len = 0; +#endif /* use same message size as in ssl3_get_certificate_request() * as ServerKeyExchange message may be skipped */ @@ -980,6 +1026,13 @@ s->session->sess_cert->peer_dh_tmp=NULL; } #endif +#ifndef OPENSSL_NO_ECDH + if (s->session->sess_cert->peer_ecdh_tmp) + { + EC_KEY_free(s->session->sess_cert->peer_ecdh_tmp); + s->session->sess_cert->peer_ecdh_tmp=NULL; + } +#endif } else { @@ -1121,6 +1174,101 @@ goto f_err; } #endif /* !OPENSSL_NO_DH */ + +#ifndef OPENSSL_NO_ECDH + else if (alg & SSL_kECDHE) + { + if ((ecdh=EC_KEY_new()) == NULL) + { + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE); + goto err; + } + + /* Extract elliptic curve parameters and the + * server's ephemeral ECDH public key. + * Keep accumulating lengths of various components in + * param_len and make sure it never exceeds n. + */ + + /* XXX: For now we only support named (not generic) curves + * and the ECParameters in this case is just two bytes. + */ + param_len=2; + if ((param_len > n) || + (*p != NAMED_CURVE_TYPE) || + ((curve_nid = curve_id2nid(*(p + 1))) == 0)) + { + al=SSL_AD_INTERNAL_ERROR; + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS); + goto f_err; + } + + if (!(ecdh->group=EC_GROUP_new_by_nid(curve_nid))) + { + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_EC_LIB); + goto err; + } + + if (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) && + (EC_GROUP_get_degree(ecdh->group) > 163)) + { + al=SSL_AD_EXPORT_RESTRICTION; + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_ECGROUP_TOO_LARGE_FOR_CIPHER); + goto f_err; + } + + p+=2; + + /* Next, get the encoded ECPoint */ + if (((srvr_ecpoint = EC_POINT_new(ecdh->group)) == NULL) || + ((bn_ctx = BN_CTX_new()) == NULL)) + { + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE); + goto err; + } + + encoded_pt_len = *p; /* length of encoded point */ + p+=1; + param_len += (1 + encoded_pt_len); + if ((param_len > n) || + (EC_POINT_oct2point(ecdh->group, srvr_ecpoint, + p, encoded_pt_len, bn_ctx) == 0)) + { + al=SSL_AD_DECODE_ERROR; + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_BAD_ECPOINT); + goto f_err; + } + + n-=param_len; + p+=encoded_pt_len; + + /* The ECC/TLS specification does not mention + * the use of DSA to sign ECParameters in the server + * key exchange message. We do support RSA and ECDSA. + */ + if (0) ; +#ifndef OPENSSL_NO_RSA + else if (alg & SSL_aRSA) + pkey=X509_get_pubkey(s->session->sess_cert->peer_pkeys[SSL_PKEY_RSA_ENC].x509); +#endif +#ifndef OPENSSL_NO_ECDSA + else if (alg & SSL_aECDSA) + pkey=X509_get_pubkey(s->session->sess_cert->peer_pkeys[SSL_PKEY_ECC].x509); +#endif + /* else anonymous ECDH, so no certificate or pkey. */ + ecdh->pub_key = srvr_ecpoint; + s->session->sess_cert->peer_ecdh_tmp=ecdh; + ecdh=NULL; + BN_CTX_free(bn_ctx); + srvr_ecpoint = NULL; + } + else if (alg & SSL_kECDH) + { + al=SSL_AD_UNEXPECTED_MESSAGE; + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_UNEXPECTED_MESSAGE); + goto f_err; + } +#endif /* !OPENSSL_NO_ECDH */ if (alg & SSL_aFZA) { al=SSL_AD_HANDSHAKE_FAILURE; @@ -1131,7 +1279,6 @@ /* p points to the next byte, there are 'n' bytes left */ - /* if it was signed, check the signature */ if (pkey != NULL) { @@ -1201,6 +1348,24 @@ } else #endif +#ifndef OPENSSL_NO_ECDSA + if (pkey->type == EVP_PKEY_ECDSA) + { + /* let's do ECDSA */ + EVP_VerifyInit_ex(&md_ctx,EVP_ecdsa(), NULL); + EVP_VerifyUpdate(&md_ctx,&(s->s3->client_random[0]),SSL3_RANDOM_SIZE); + EVP_VerifyUpdate(&md_ctx,&(s->s3->server_random[0]),SSL3_RANDOM_SIZE); + EVP_VerifyUpdate(&md_ctx,param,param_len); + if (!EVP_VerifyFinal(&md_ctx,p,(int)n,pkey)) + { + /* bad signature */ + al=SSL_AD_DECRYPT_ERROR; + SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_BAD_SIGNATURE); + goto f_err; + } + } + else +#endif { SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_INTERNAL_ERROR); goto err; @@ -1236,6 +1401,12 @@ if (dh != NULL) DH_free(dh); #endif +#ifndef OPENSSL_NO_ECDH + BN_CTX_free(bn_ctx); + EC_POINT_free(srvr_ecpoint); + if (ecdh != NULL) + EC_KEY_free(ecdh); +#endif EVP_MD_CTX_cleanup(&md_ctx); return(-1); } @@ -1423,6 +1594,14 @@ #ifndef OPENSSL_NO_KRB5 KSSL_ERR kssl_err; #endif /* OPENSSL_NO_KRB5 */ +#ifndef OPENSSL_NO_ECDH + EC_KEY *clnt_ecdh = NULL; + EC_POINT *srvr_ecpoint = NULL; + EVP_PKEY *srvr_pub_pkey = NULL; + unsigned char *encodedPoint = NULL; + int encoded_pt_len = 0; + BN_CTX * bn_ctx = NULL; +#endif if (s->state == SSL3_ST_CW_KEY_EXCH_A) { @@ -1680,10 +1859,180 @@ /* perhaps clean things up a bit EAY EAY EAY EAY*/ } #endif + +#ifndef OPENSSL_NO_ECDH + else if ((l & SSL_kECDH) || (l & SSL_kECDHE)) + { + EC_GROUP *srvr_group = NULL; + int ecdh_clnt_cert = 0; + + /* Did we send out the client's + * ECDH share for use in premaster + * computation as part of client certificate? + * If so, set ecdh_clnt_cert to 1. + */ + if ((l & SSL_kECDH) && (s->cert != NULL)) + { + /* XXX: For now, we do not support client + * authentication using ECDH certificates. + * To add such support, one needs to add + * code that checks for appropriate + * conditions and sets ecdh_clnt_cert to 1. + * For example, the cert have an ECC + * key on the same curve as the server's + * and the key should be authorized for + * key agreement. + * + * One also needs to add code in ssl3_connect + * to skip sending the certificate verify + * message. + * + * if ((s->cert->key->privatekey != NULL) && + * (s->cert->key->privatekey->type == + * EVP_PKEY_ECC) && ...) + * ecdh_clnt_cert = 1; + */ + } + + if (s->session->sess_cert->peer_ecdh_tmp != NULL) + { + srvr_group = s->session->sess_cert-> \ + peer_ecdh_tmp->group; + srvr_ecpoint = s->session->sess_cert-> \ + peer_ecdh_tmp->pub_key; + } + else + { + /* Get the Server Public Key from Cert */ + srvr_pub_pkey = X509_get_pubkey(s->session-> \ + sess_cert->peer_pkeys[SSL_PKEY_ECC].x509); + if ((srvr_pub_pkey == NULL) || + (srvr_pub_pkey->type != EVP_PKEY_ECDSA) || + (srvr_pub_pkey->pkey.eckey == NULL)) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, + ERR_R_INTERNAL_ERROR); + goto err; + } + + srvr_group = srvr_pub_pkey->pkey.eckey->group; + srvr_ecpoint = + srvr_pub_pkey->pkey.eckey->pub_key; + } + + if ((srvr_group == NULL) || (srvr_ecpoint == NULL)) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, + ERR_R_INTERNAL_ERROR); + goto err; + } + + if ((clnt_ecdh=EC_KEY_new()) == NULL) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE); + goto err; + } + + clnt_ecdh->group = srvr_group; + if (ecdh_clnt_cert) + { + /* Reuse key info from our certificate + * We only need our private key to perform + * the ECDH computation. + */ + clnt_ecdh->priv_key = BN_dup(s->cert->key-> \ + privatekey->pkey.eckey->priv_key); + } + else + { + /* Generate a new ECDH key pair */ + if (!(EC_KEY_generate_key(clnt_ecdh))) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB); + goto err; + } + } + + /* use the 'p' output buffer for the ECDH key, but + * make sure to clear it out afterwards + */ + + n=ECDH_compute_key(p, srvr_ecpoint, clnt_ecdh); + if (n <= 0) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, + ERR_R_ECDH_LIB); + goto err; + } + + /* generate master key from the result */ + s->session->master_key_length = s->method->ssl3_enc \ + -> generate_master_secret(s, + s->session->master_key, + p, n); + + memset(p, 0, n); /* clean up */ + + if (ecdh_clnt_cert) + { + /* Send empty client key exch message */ + n = 0; + } + else + { + /* First check the size of encoding and + * allocate memory accordingly. + */ + encoded_pt_len = + EC_POINT_point2oct(clnt_ecdh->group, + clnt_ecdh->pub_key, + POINT_CONVERSION_UNCOMPRESSED, + NULL, 0, NULL); + + encodedPoint = (unsigned char *) + OPENSSL_malloc(encoded_pt_len * + sizeof(unsigned char)); + bn_ctx = BN_CTX_new(); + if ((encodedPoint == NULL) || + (bn_ctx == NULL)) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE); + goto err; + } + + /* Encode the public key */ + n = EC_POINT_point2oct(clnt_ecdh->group, + clnt_ecdh->pub_key, + POINT_CONVERSION_UNCOMPRESSED, + encodedPoint, encoded_pt_len, bn_ctx); + + *p = n; /* length of encoded point */ + /* Encoded point will be copied here */ + p += 1; + /* copy the point */ + memcpy((unsigned char *)p, encodedPoint, n); + /* increment n to account for length field */ + n += 1; + } + + /* Free allocated memory */ + BN_CTX_free(bn_ctx); + if (encodedPoint != NULL) OPENSSL_free(encodedPoint); + if (clnt_ecdh != NULL) + { + /* group is shared */ + clnt_ecdh->group = NULL; + EC_KEY_free(clnt_ecdh); + } + EVP_PKEY_free(srvr_pub_pkey); + } +#endif /* !OPENSSL_NO_ECDH */ else { - ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_HANDSHAKE_FAILURE); - SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,ERR_R_INTERNAL_ERROR); + ssl3_send_alert(s, SSL3_AL_FATAL, + SSL_AD_HANDSHAKE_FAILURE); + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, + ERR_R_INTERNAL_ERROR); goto err; } @@ -1699,6 +2048,17 @@ /* SSL3_ST_CW_KEY_EXCH_B */ return(ssl3_do_write(s,SSL3_RT_HANDSHAKE)); err: +#ifndef OPENSSL_NO_ECDH + BN_CTX_free(bn_ctx); + if (encodedPoint != NULL) OPENSSL_free(encodedPoint); + if (clnt_ecdh != NULL) + { + /* group is shared */ + clnt_ecdh->group = NULL; + EC_KEY_free(clnt_ecdh); + } + EVP_PKEY_free(srvr_pub_pkey); +#endif return(-1); } @@ -1757,6 +2117,23 @@ } else #endif +#ifndef OPENSSL_NO_ECDSA + if (pkey->type == EVP_PKEY_ECDSA) + { + if (!ECDSA_sign(pkey->save_type, + &(data[MD5_DIGEST_LENGTH]), + SHA_DIGEST_LENGTH,&(p[2]), + (unsigned int *)&j,pkey->pkey.eckey)) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_VERIFY, + ERR_R_ECDSA_LIB); + goto err; + } + s2n(j,p); + n=j+2; + } + else +#endif { SSLerr(SSL_F_SSL3_SEND_CLIENT_VERIFY,ERR_R_INTERNAL_ERROR); goto err; @@ -1888,6 +2265,21 @@ /* This is the passed certificate */ idx=sc->peer_cert_type; +#ifndef OPENSSL_NO_ECDH + if (idx == SSL_PKEY_ECC) + { + if (check_srvr_ecc_cert_and_alg(sc->peer_pkeys[idx].x509, + s->s3->tmp.new_cipher) == 0) + { /* check failed */ + SSLerr(SSL_F_SSL3_CHECK_CERT_AND_ALGORITHM,SSL_R_BAD_ECC_CERT); + goto f_err; + } + else + { + return 1; + } + } +#endif pkey=X509_get_pubkey(sc->peer_pkeys[idx].x509); i=X509_certificate_type(sc->peer_pkeys[idx].x509,pkey); EVP_PKEY_free(pkey); @@ -1973,3 +2365,44 @@ return(0); } + +#ifndef OPENSSL_NO_ECDH +/* 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) */ + static int nid_list[26] = + { + 0, + NID_sect163k1, /* sect163k1 (1) */ + NID_sect163r1, /* sect163r1 (2) */ + NID_sect163r2, /* sect163r2 (3) */ + NID_sect193r1, /* sect193r1 (4) */ + NID_sect193r2, /* sect193r2 (5) */ + NID_sect233k1, /* sect233k1 (6) */ + NID_sect233r1, /* sect233r1 (7) */ + NID_sect239k1, /* sect239k1 (8) */ + NID_sect283k1, /* sect283k1 (9) */ + NID_sect283r1, /* sect283r1 (10) */ + NID_sect409k1, /* sect409k1 (11) */ + NID_sect409r1, /* sect409r1 (12) */ + NID_sect571k1, /* sect571k1 (13) */ + NID_sect571r1, /* sect571r1 (14) */ + NID_secp160k1, /* secp160k1 (15) */ + NID_secp160r1, /* secp160r1 (16) */ + NID_secp160r2, /* secp160r2 (17) */ + NID_secp192k1, /* secp192k1 (18) */ + NID_X9_62_prime192v1, /* secp192r1 (19) */ + NID_secp224k1, /* secp224k1 (20) */ + NID_secp224r1, /* secp224r1 (21) */ + NID_secp256k1, /* secp256k1 (22) */ + NID_X9_62_prime256v1, /* secp256r1 (23) */ + NID_secp384r1, /* secp384r1 (24) */ + NID_secp521r1 /* secp521r1 (25) */ + }; + + if ((curve_id < 1) || (curve_id > 25)) return 0; + + return nid_list[curve_id]; +} +#endif