ITS#9054 Add support for multiple EECDH curves

Requires OpenSSL 1.0.2 or newer

doc/man/man3/ldap_get_option.3

@@ -740,7 +740,7 @@ and its contents need to be freed by the caller using
 .BR ldap_memfree (3).
 .TP
 .B LDAP_OPT_X_TLS_ECNAME
-Gets/sets the name of the curve used for 
+Gets/sets the name of the curve(s) used for
 elliptic curve key exchanges.
 .BR invalue
 must be

doc/man/man5/ldap.conf.5

@@ -327,6 +327,12 @@ is always used before
 Specifies the file that contains the client certificate.
 .B This is a user-only option.
 .TP
+.B TLS_ECNAME <name>
+Specify the name of the curve(s) to use for Elliptic curve Diffie-Hellman
+ephemeral key exchange.  This option is only used for OpenSSL.
+This option is not used with GnuTLS; the curves may be
+chosen in the GnuTLS ciphersuite specification.
+.TP
 .B TLS_KEY <filename>
 Specifies the file that contains the private key that matches the certificate
 stored in the

doc/man/man5/slapd-config.5

@@ -908,9 +908,9 @@ You should append "!ADH" to your cipher suites to ensure that these suites
 are not used.
 .TP
 .B olcTLSECName: <name>
-Specify the name of a curve to use for Elliptic curve Diffie-Hellman
-ephemeral key exchange.  This is required to enable ECDHE algorithms in
-OpenSSL.  This option is not used with GnuTLS; the curves may be
+Specify the name of the curve(s) to use for Elliptic curve Diffie-Hellman
+ephemeral key exchange.  This option is only used for OpenSSL.
+This option is not used with GnuTLS; the curves may be
 chosen in the GnuTLS ciphersuite specification.
 .TP
 .B olcTLSProtocolMin: <major>[.<minor>]

doc/man/man5/slapd.conf.5

@@ -1139,9 +1139,9 @@ You should append "!ADH" to your cipher suites to ensure that these suites
 are not used.
 .TP
 .B TLSECName <name>
-Specify the name of a curve to use for Elliptic curve Diffie-Hellman
-ephemeral key exchange.  This is required to enable ECDHE algorithms in
-OpenSSL.  This option is not used with GnuTLS; the curves may be
+Specify the name of the curve(s) to use for Elliptic curve Diffie-Hellman
+ephemeral key exchange.  This option is only used for OpenSSL.
+This option is not used with GnuTLS; the curves may be
 chosen in the GnuTLS ciphersuite specification.
 .TP
 .B TLSProtocolMin <major>[.<minor>]

libraries/libldap/init.c

@@ -123,6 +123,7 @@ static const struct ol_attribute {
 	{0, ATTR_TLS,	"TLS_CIPHER_SUITE",	NULL,	LDAP_OPT_X_TLS_CIPHER_SUITE},
 	{0, ATTR_TLS,	"TLS_PROTOCOL_MIN",	NULL,	LDAP_OPT_X_TLS_PROTOCOL_MIN},
 	{0, ATTR_TLS,	"TLS_PEERKEY_HASH",	NULL,	LDAP_OPT_X_TLS_PEERKEY_HASH},
+	{0, ATTR_TLS,	"TLS_ECNAME",		NULL,	LDAP_OPT_X_TLS_ECNAME},
 
 #ifdef HAVE_OPENSSL_CRL
 	{0, ATTR_TLS,	"TLS_CRLCHECK",		NULL,	LDAP_OPT_X_TLS_CRLCHECK},

libraries/libldap/tls2.c

@@ -342,7 +342,7 @@ ldap_int_tls_connect( LDAP *ld, LDAPConn *conn, const char *host )
 	Sockbuf *sb = conn->lconn_sb;
 	int	err;
 	tls_session	*ssl = NULL;
-	char *sni = host;
+	char *sni = (char *)host;
 
 	if ( HAS_TLS( sb )) {
 		ber_sockbuf_ctrl( sb, LBER_SB_OPT_GET_SSL, (void *)&ssl );
@@ -580,6 +580,7 @@ ldap_pvt_tls_config( LDAP *ld, int option, const char *arg )
 	case LDAP_OPT_X_TLS_CIPHER_SUITE:
 	case LDAP_OPT_X_TLS_DHFILE:
 	case LDAP_OPT_X_TLS_PEERKEY_HASH:
+	case LDAP_OPT_X_TLS_ECNAME:
 	case LDAP_OPT_X_TLS_CRLFILE:	/* GnuTLS only */
 		return ldap_pvt_tls_set_option( ld, option, (void *) arg );
 

libraries/libldap/tls_o.c

@@ -453,34 +453,30 @@ tlso_ctx_init( struct ldapoptions *lo, struct ldaptls *lt, int is_server )
 		DH_free( dh );
 	}
 
-	if ( is_server && lo->ldo_tls_ecname ) {
+	if ( lo->ldo_tls_ecname ) {
 #ifdef OPENSSL_NO_EC
 		Debug0( LDAP_DEBUG_ANY,
 			"TLS: Elliptic Curves not supported.\n" );
 		return -1;
 #else
-		EC_KEY *ecdh;
-
-		int nid = OBJ_sn2nid( lt->lt_ecname );
-		if ( nid == NID_undef ) {
+		if ( SSL_CTX_set1_curves_list( ctx, lt->lt_ecname )) {
 			Debug1( LDAP_DEBUG_ANY,
-				"TLS: could not use EC name `%s'.\n",
+				"TLS: could not set EC name `%s'.\n",
 				lo->ldo_tls_ecname );
 			tlso_report_error();
 			return -1;
 		}
-		ecdh = EC_KEY_new_by_curve_name( nid );
-		if ( ecdh == NULL ) {
-			Debug1( LDAP_DEBUG_ANY,
-				"TLS: could not generate key for EC name `%s'.\n",
-				lo->ldo_tls_ecname );
-			tlso_report_error();
-			return -1;
+	/*
+	 * This is a NOP in OpenSSL 1.1.0 and later, where curves are always
+	 * auto-negotiated.
+	 */
+#if OPENSSL_VERSION_NUMBER < 0x10100000UL
+		if ( SSL_CTX_set_ecdh_auto( ctx, 1 ) <= 0 ) {
+			Debug0( LDAP_DEBUG_ANY,
+				"TLS: could not enable automatic EC negotiation.\n" );
 		}
-		SSL_CTX_set_tmp_ecdh( ctx, ecdh );
-		SSL_CTX_set_options( ctx, SSL_OP_SINGLE_ECDH_USE );
-		EC_KEY_free( ecdh );
 #endif
+#endif	/* OPENSSL_NO_EC */
 	}
 
 	if ( tlso_opt_trace ) {