Share code between In-CliKeyExch and Out-CliKeyExch
The postprocessing code for the server-side incoming client key
exchange and the client-side outgoing client key exchange both
contain the same code-paths for building the premaster secret
depending on the chosen ciphersuite (e.g., for ECDHE-PSK,
concatenating the ECDHE secret with the chosen PSK).
This commit moves this common code to ssl_tls.c, allowing
client- and server-side to share it.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 6187eb0..e651f29 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1653,6 +1653,111 @@
#endif /* MBEDTLS_SHA512_C */
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
+int mbedtls_ssl_build_pms( mbedtls_ssl_context *ssl )
+{
+ int ret;
+
+ mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
+ mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
+
+#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
+ if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
+ {
+ if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
+ ssl->handshake->premaster,
+ MBEDTLS_PREMASTER_SIZE,
+ &ssl->handshake->pmslen,
+ mbedtls_ssl_conf_get_frng( ssl->conf ),
+ ssl->conf->p_rng ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
+ return( ret );
+ }
+
+ MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+ if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
+ mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
+ mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
+ mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
+ {
+ if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
+ &ssl->handshake->pmslen,
+ ssl->handshake->premaster,
+ MBEDTLS_MPI_MAX_SIZE,
+ mbedtls_ssl_conf_get_frng( ssl->conf ),
+ ssl->conf->p_rng ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
+ return( ret );
+ }
+
+ MBEDTLS_SSL_DEBUG_MPI( 3, "ECDH: z", &ssl->handshake->ecdh_ctx.z );
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
+ MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
+ MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
+ MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
+#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+ if( mbedtls_ssl_ciphersuite_uses_psk( ciphersuite_info ) )
+ {
+ if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
+ mbedtls_ssl_suite_get_key_exchange( ciphersuite_info ) ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
+ return( ret );
+ }
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+ if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info ) ==
+ MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+ {
+ ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
+ ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
+ mbedtls_ssl_conf_get_frng( ssl->conf ),
+ ssl->conf->p_rng );
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
+ return( ret );
+ }
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
+#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
+ if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
+ == MBEDTLS_KEY_EXCHANGE_RSA )
+ {
+ ((void) ret);
+ /* The premaster secret has already been by
+ * ssl_rsa_generate_partial_pms(). Only the
+ * PMS length needs to be set. */
+ ssl->handshake->pmslen = 48;
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ return( 0 );
+}
+
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
int mbedtls_ssl_psk_derive_premaster( mbedtls_ssl_context *ssl, mbedtls_key_exchange_type_t key_ex )
{