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esp8266/ssl/tls1_clnt.c
Ivan Grokhotkov 9eaeca3a03 Postpone freeing of X509 context to the first data exchange after handshake 
X509 context contains certificate fingerprint and various names which may be used to verify the certificate.
Previously we would free it right after the handshake completion, which prevented the client from actually using any information from X509 context.
Postponing this to the first ssl_read/ssl_write call after the handshake, we give the client a chance to verify the certificate.

Also added logging to ssl_match_fingerprint function in case fingerprint doesn't match expected value.
2016-02-26 16:21:09 +03:00

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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);
/* 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->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)
{
ret = ssl_read(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;
if (ssl->host_name != NULL) {
unsigned int host_len = strlen(ssl->host_name);
buf[offset++] = 0;
buf[offset++] = host_len+9; /* extensions length */
buf[offset++] = 0;
buf[offset++] = 0; /* server_name(0) (65535) */
buf[offset++] = 0;
buf[offset++] = host_len+5; /* server_name length */
buf[offset++] = 0;
buf[offset++] = host_len+3; /* server_list length */
buf[offset++] = 0; /* host_name(0) (255) */
buf[offset++] = 0;
buf[offset++] = host_len; /* host_name length */
strncpy((char*) &buf[offset], ssl->host_name, host_len);
offset += host_len;
}
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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