/* * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL licenses, (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * https://www.openssl.org/source/license.html * or in the file LICENSE in the source distribution. */ #include #include #include #include "handshake_helper.h" /* * Since there appears to be no way to extract the sent/received alert * from the SSL object directly, we use the info callback and stash * the result in ex_data. */ typedef struct handshake_ex_data { int alert_sent; int alert_received; } HANDSHAKE_EX_DATA; static int ex_data_idx; static void info_callback(const SSL *s, int where, int ret) { if (where & SSL_CB_ALERT) { HANDSHAKE_EX_DATA *ex_data = (HANDSHAKE_EX_DATA*)(SSL_get_ex_data(s, ex_data_idx)); if (where & SSL_CB_WRITE) { ex_data->alert_sent = ret; } else { ex_data->alert_received = ret; } } } typedef enum { PEER_SUCCESS, PEER_RETRY, PEER_ERROR } peer_status_t; static peer_status_t do_handshake_step(SSL *ssl) { int ret; ret = SSL_do_handshake(ssl); if (ret == 1) { return PEER_SUCCESS; } else if (ret == 0) { return PEER_ERROR; } else { int error = SSL_get_error(ssl, ret); /* Memory bios should never block with SSL_ERROR_WANT_WRITE. */ if (error == SSL_ERROR_WANT_READ) return PEER_RETRY; else return PEER_ERROR; } } typedef enum { /* Both parties succeeded. */ HANDSHAKE_SUCCESS, /* Client errored. */ CLIENT_ERROR, /* Server errored. */ SERVER_ERROR, /* Peers are in inconsistent state. */ INTERNAL_ERROR, /* One or both peers not done. */ HANDSHAKE_RETRY } handshake_status_t; /* * Determine the handshake outcome. * last_status: the status of the peer to have acted last. * previous_status: the status of the peer that didn't act last. * client_spoke_last: 1 if the client went last. */ static handshake_status_t handshake_status(peer_status_t last_status, peer_status_t previous_status, int client_spoke_last) { switch (last_status) { case PEER_SUCCESS: switch (previous_status) { case PEER_SUCCESS: /* Both succeeded. */ return HANDSHAKE_SUCCESS; case PEER_RETRY: /* Let the first peer finish. */ return HANDSHAKE_RETRY; case PEER_ERROR: /* * Second peer succeeded despite the fact that the first peer * already errored. This shouldn't happen. */ return INTERNAL_ERROR; } case PEER_RETRY: if (previous_status == PEER_RETRY) { /* Neither peer is done. */ return HANDSHAKE_RETRY; } else { /* * Deadlock: second peer is waiting for more input while first * peer thinks they're done (no more input is coming). */ return INTERNAL_ERROR; } case PEER_ERROR: switch (previous_status) { case PEER_SUCCESS: /* * First peer succeeded but second peer errored. * TODO(emilia): we should be able to continue here (with some * application data?) to ensure the first peer receives the * alert / close_notify. */ return client_spoke_last ? CLIENT_ERROR : SERVER_ERROR; case PEER_RETRY: /* We errored; let the peer finish. */ return HANDSHAKE_RETRY; case PEER_ERROR: /* Both peers errored. Return the one that errored first. */ return client_spoke_last ? SERVER_ERROR : CLIENT_ERROR; } } /* Control should never reach here. */ return INTERNAL_ERROR; } HANDSHAKE_RESULT do_handshake(SSL_CTX *server_ctx, SSL_CTX *client_ctx) { SSL *server, *client; BIO *client_to_server, *server_to_client; HANDSHAKE_EX_DATA server_ex_data, client_ex_data; HANDSHAKE_RESULT ret; int client_turn = 1; peer_status_t client_status = PEER_RETRY, server_status = PEER_RETRY; handshake_status_t status = HANDSHAKE_RETRY; server = SSL_new(server_ctx); client = SSL_new(client_ctx); OPENSSL_assert(server != NULL && client != NULL); memset(&server_ex_data, 0, sizeof(server_ex_data)); memset(&client_ex_data, 0, sizeof(client_ex_data)); memset(&ret, 0, sizeof(ret)); ret.result = SSL_TEST_INTERNAL_ERROR; client_to_server = BIO_new(BIO_s_mem()); server_to_client = BIO_new(BIO_s_mem()); OPENSSL_assert(client_to_server != NULL && server_to_client != NULL); /* Non-blocking bio. */ BIO_set_nbio(client_to_server, 1); BIO_set_nbio(server_to_client, 1); SSL_set_connect_state(client); SSL_set_accept_state(server); /* The bios are now owned by the SSL object. */ SSL_set_bio(client, server_to_client, client_to_server); OPENSSL_assert(BIO_up_ref(server_to_client) > 0); OPENSSL_assert(BIO_up_ref(client_to_server) > 0); SSL_set_bio(server, client_to_server, server_to_client); ex_data_idx = SSL_get_ex_new_index(0, "ex data", NULL, NULL, NULL); OPENSSL_assert(ex_data_idx >= 0); OPENSSL_assert(SSL_set_ex_data(server, ex_data_idx, &server_ex_data) == 1); OPENSSL_assert(SSL_set_ex_data(client, ex_data_idx, &client_ex_data) == 1); SSL_set_info_callback(server, &info_callback); SSL_set_info_callback(client, &info_callback); /* * Half-duplex handshake loop. * Client and server speak to each other synchronously in the same process. * We use non-blocking BIOs, so whenever one peer blocks for read, it * returns PEER_RETRY to indicate that it's the other peer's turn to write. * The handshake succeeds once both peers have succeeded. If one peer * errors out, we also let the other peer retry (and presumably fail). */ for(;;) { if (client_turn) { client_status = do_handshake_step(client); status = handshake_status(client_status, server_status, 1 /* client went last */); } else { server_status = do_handshake_step(server); status = handshake_status(server_status, client_status, 0 /* server went last */); } switch (status) { case HANDSHAKE_SUCCESS: ret.result = SSL_TEST_SUCCESS; goto err; case CLIENT_ERROR: ret.result = SSL_TEST_CLIENT_FAIL; goto err; case SERVER_ERROR: ret.result = SSL_TEST_SERVER_FAIL; goto err; case INTERNAL_ERROR: ret.result = SSL_TEST_INTERNAL_ERROR; goto err; case HANDSHAKE_RETRY: /* Continue. */ client_turn ^= 1; break; } } err: ret.server_alert_sent = server_ex_data.alert_sent; ret.server_alert_received = client_ex_data.alert_received; ret.client_alert_sent = client_ex_data.alert_sent; ret.client_alert_received = server_ex_data.alert_received; ret.server_protocol = SSL_version(server); ret.client_protocol = SSL_version(client); SSL_free(server); SSL_free(client); return ret; }