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/*
* Copyright (c) 2007, Cameron Rich
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the axTLS project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <stdio.h>
#include "os_port.h"
#include "ssl.h"
#ifdef CONFIG_SSL_ENABLE_CLIENT /* all commented out if no client */
static int send_client_hello(SSL *ssl);
static int process_server_hello(SSL *ssl);
static int process_server_hello_done(SSL *ssl);
static int send_client_key_xchg(SSL *ssl);
static int process_cert_req(SSL *ssl);
static int send_cert_verify(SSL *ssl);
/*
* Establish a new SSL connection to an SSL server.
*/
EXP_FUNC SSL * STDCALL ssl_client_new(SSL_CTX *ssl_ctx, int client_fd, const
uint8_t *session_id, uint8_t sess_id_size)
{
SSL *ssl = ssl_new(ssl_ctx, client_fd);
ssl->version = SSL_PROTOCOL_VERSION_MAX; /* try top version first */
if (session_id && ssl_ctx->num_sessions)
{
if (sess_id_size > SSL_SESSION_ID_SIZE) /* validity check */
{
ssl_free(ssl);
return NULL;
}
memcpy(ssl->session_id, session_id, sess_id_size);
ssl->sess_id_size = sess_id_size;
SET_SSL_FLAG(SSL_SESSION_RESUME); /* just flag for later */
}
SET_SSL_FLAG(SSL_IS_CLIENT);
do_client_connect(ssl);
return ssl;
}
/*
* Process the handshake record.
*/
int do_clnt_handshake(SSL *ssl, int handshake_type, uint8_t *buf, int hs_len)
{
int ret;
/* To get here the state must be valid */
switch (handshake_type)
{
case HS_SERVER_HELLO:
ret = process_server_hello(ssl);
break;
case HS_CERTIFICATE:
ret = process_certificate(ssl, &ssl->x509_ctx);
break;
case HS_SERVER_HELLO_DONE:
if ((ret = process_server_hello_done(ssl)) == SSL_OK)
{
if (IS_SET_SSL_FLAG(SSL_HAS_CERT_REQ))
{
if ((ret = send_certificate(ssl)) == SSL_OK &&
(ret = send_client_key_xchg(ssl)) == SSL_OK)
{
send_cert_verify(ssl);
}
}
else
{
ret = send_client_key_xchg(ssl);
}
if (ret == SSL_OK &&
(ret = send_change_cipher_spec(ssl)) == SSL_OK)
{
ret = send_finished(ssl);
}
}
break;
case HS_CERT_REQ:
ret = process_cert_req(ssl);
break;
case HS_FINISHED:
ret = process_finished(ssl, buf, hs_len);
disposable_free(ssl); /* free up some memory */
/* note: client renegotiation is not allowed after this */
break;
case HS_HELLO_REQUEST:
disposable_new(ssl);
ret = do_client_connect(ssl);
break;
default:
ret = SSL_ERROR_INVALID_HANDSHAKE;
break;
}
return ret;
}
/*
* Do the handshaking from the beginning.
*/
int do_client_connect(SSL *ssl)
{
int ret = SSL_OK;
send_client_hello(ssl); /* send the client hello */
ssl->bm_read_index = 0;
ssl->bm_rread_index = 0;
ssl->next_state = HS_SERVER_HELLO;
ssl->hs_status = SSL_NOT_OK; /* not connected */
/* sit in a loop until it all looks good */
if (!IS_SET_SSL_FLAG(SSL_CONNECT_IN_PARTS))
{
while (ssl->hs_status != SSL_OK)
{
/* Use internal, synchronous ssl_read */
ret = ssl_readi(ssl, NULL);
if (ret < SSL_OK)
break;
}
ssl->hs_status = ret; /* connected? */
}
return ret;
}
/*
* Send the initial client hello.
*/
static int send_client_hello(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
time_t tm = time(NULL);
uint8_t *tm_ptr = &buf[6]; /* time will go here */
int i, offset;
buf[0] = HS_CLIENT_HELLO;
buf[1] = 0;
buf[2] = 0;
/* byte 3 is calculated later */
buf[4] = 0x03;
buf[5] = ssl->version & 0x0f;
/* client random value - spec says that 1st 4 bytes are big endian time */
*tm_ptr++ = (uint8_t)(((long)tm & 0xff000000) >> 24);
*tm_ptr++ = (uint8_t)(((long)tm & 0x00ff0000) >> 16);
*tm_ptr++ = (uint8_t)(((long)tm & 0x0000ff00) >> 8);
*tm_ptr++ = (uint8_t)(((long)tm & 0x000000ff));
get_random(SSL_RANDOM_SIZE-4, &buf[10]);
memcpy(ssl->dc->client_random, &buf[6], SSL_RANDOM_SIZE);
offset = 6 + SSL_RANDOM_SIZE;
/* give session resumption a go */
if (IS_SET_SSL_FLAG(SSL_SESSION_RESUME)) /* set initially by user */
{
buf[offset++] = ssl->sess_id_size;
memcpy(&buf[offset], ssl->session_id, ssl->sess_id_size);
offset += ssl->sess_id_size;
CLR_SSL_FLAG(SSL_SESSION_RESUME); /* clear so we can set later */
}
else
{
/* no session id - because no session resumption just yet */
buf[offset++] = 0;
}
buf[offset++] = 0; /* number of ciphers */
buf[offset++] = NUM_PROTOCOLS*2;/* number of ciphers */
/* put all our supported protocols in our request */
for (i = 0; i < NUM_PROTOCOLS; i++)
{
buf[offset++] = 0; /* cipher we are using */
buf[offset++] = ssl_prot_prefs[i];
}
buf[offset++] = 1; /* no compression */
buf[offset++] = 0;
buf[3] = offset - 4; /* handshake size */
return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, offset);
}
/*
* Process the server hello.
*/
static int process_server_hello(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
int pkt_size = ssl->bm_index;
int num_sessions = ssl->ssl_ctx->num_sessions;
uint8_t sess_id_size;
int offset, ret = SSL_OK;
/* check that we are talking to a TLSv1 server */
uint8_t version = (buf[4] << 4) + buf[5];
if (version > SSL_PROTOCOL_VERSION_MAX)
{
version = SSL_PROTOCOL_VERSION_MAX;
}
else if (ssl->version < SSL_PROTOCOL_MIN_VERSION)
{
ret = SSL_ERROR_INVALID_VERSION;
ssl_display_error(ret);
goto error;
}
ssl->version = version;
/* get the server random value */
memcpy(ssl->dc->server_random, &buf[6], SSL_RANDOM_SIZE);
offset = 6 + SSL_RANDOM_SIZE; /* skip of session id size */
sess_id_size = buf[offset++];
if (sess_id_size > SSL_SESSION_ID_SIZE)
{
ret = SSL_ERROR_INVALID_SESSION;
goto error;
}
if (num_sessions)
{
ssl->session = ssl_session_update(num_sessions,
ssl->ssl_ctx->ssl_sessions, ssl, &buf[offset]);
memcpy(ssl->session->session_id, &buf[offset], sess_id_size);
/* pad the rest with 0's */
if (sess_id_size < SSL_SESSION_ID_SIZE)
{
memset(&ssl->session->session_id[sess_id_size], 0,
SSL_SESSION_ID_SIZE-sess_id_size);
}
}
memcpy(ssl->session_id, &buf[offset], sess_id_size);
ssl->sess_id_size = sess_id_size;
offset += sess_id_size;
/* get the real cipher we are using */
ssl->cipher = buf[++offset];
ssl->next_state = IS_SET_SSL_FLAG(SSL_SESSION_RESUME) ?
HS_FINISHED : HS_CERTIFICATE;
offset++; // skip the compr
PARANOIA_CHECK(pkt_size, offset);
ssl->dc->bm_proc_index = offset+1;
error:
return ret;
}
/**
* Process the server hello done message.
*/
static int process_server_hello_done(SSL *ssl)
{
ssl->next_state = HS_FINISHED;
return SSL_OK;
}
/*
* Send a client key exchange message.
*/
static int send_client_key_xchg(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
uint8_t premaster_secret[SSL_SECRET_SIZE];
int enc_secret_size = -1;
buf[0] = HS_CLIENT_KEY_XCHG;
buf[1] = 0;
premaster_secret[0] = 0x03; /* encode the version number */
premaster_secret[1] = SSL_PROTOCOL_MINOR_VERSION; /* must be TLS 1.1 */
get_random(SSL_SECRET_SIZE-2, &premaster_secret[2]);
DISPLAY_RSA(ssl, ssl->x509_ctx->rsa_ctx);
/* rsa_ctx->bi_ctx is not thread-safe */
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
enc_secret_size = RSA_encrypt(ssl->x509_ctx->rsa_ctx, premaster_secret,
SSL_SECRET_SIZE, &buf[6], 0);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
buf[2] = (enc_secret_size + 2) >> 8;
buf[3] = (enc_secret_size + 2) & 0xff;
buf[4] = enc_secret_size >> 8;
buf[5] = enc_secret_size & 0xff;
generate_master_secret(ssl, premaster_secret);
return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, enc_secret_size+6);
}
/*
* Process the certificate request.
*/
static int process_cert_req(SSL *ssl)
{
uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
int ret = SSL_OK;
int offset = (buf[2] << 4) + buf[3];
int pkt_size = ssl->bm_index;
/* don't do any processing - we will send back an RSA certificate anyway */
ssl->next_state = HS_SERVER_HELLO_DONE;
SET_SSL_FLAG(SSL_HAS_CERT_REQ);
ssl->dc->bm_proc_index += offset;
PARANOIA_CHECK(pkt_size, offset);
error:
return ret;
}
/*
* Send a certificate verify message.
*/
static int send_cert_verify(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
uint8_t dgst[MD5_SIZE+SHA1_SIZE];
RSA_CTX *rsa_ctx = ssl->ssl_ctx->rsa_ctx;
int n = 0, ret;
DISPLAY_RSA(ssl, rsa_ctx);
buf[0] = HS_CERT_VERIFY;
buf[1] = 0;
finished_digest(ssl, NULL, dgst); /* calculate the digest */
/* rsa_ctx->bi_ctx is not thread-safe */
if (rsa_ctx)
{
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
n = RSA_encrypt(rsa_ctx, dgst, sizeof(dgst), &buf[6], 1);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
if (n == 0)
{
ret = SSL_ERROR_INVALID_KEY;
goto error;
}
}
buf[4] = n >> 8; /* add the RSA size (not officially documented) */
buf[5] = n & 0xff;
n += 2;
buf[2] = n >> 8;
buf[3] = n & 0xff;
ret = send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, n+4);
error:
return ret;
}
#endif /* CONFIG_SSL_ENABLE_CLIENT */
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