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/*
* 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 <string.h>
#include <openssl/bio.h>
#include <openssl/ssl.h>
#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;
}
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