/*
* Ensure the client has the private key by first decrypting the packet and
* then checking the packet digests.
*/
static int process_cert_verify(SSL *ssl)
{
uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
int pkt_size = ssl->bm_index;
uint8_t dgst_buf[MAX_KEY_BYTE_SIZE];
uint8_t dgst[MD5_SIZE+SHA1_SIZE];
X509_CTX *x509_ctx = ssl->x509_ctx;
int ret = SSL_OK;
int n;
PARANOIA_CHECK(pkt_size, x509_ctx->rsa_ctx->num_octets+6);
DISPLAY_RSA(ssl, x509_ctx->rsa_ctx);
/* rsa_ctx->bi_ctx is not thread-safe */
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
n = RSA_decrypt(x509_ctx->rsa_ctx, &buf[6], dgst_buf, 0);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
if (n != SHA1_SIZE + MD5_SIZE)
{
ret = SSL_ERROR_INVALID_KEY;
goto end_cert_vfy;
}
finished_digest(ssl, NULL, dgst); /* calculate the digest */
if (memcmp(dgst_buf, dgst, MD5_SIZE + SHA1_SIZE))
{
ret = SSL_ERROR_INVALID_KEY;
}
end_cert_vfy:
ssl->next_state = HS_FINISHED;
error:
return ret;
}
/*
* Pull apart a client key exchange message. Decrypt the pre-master key (using
* our RSA private key) and then work out the master key. Initialise the
* ciphers.
*/
static int ICACHE_FLASH_ATTR process_client_key_xchg(SSL *ssl)
{
uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
int pkt_size = ssl->bm_index;
int premaster_size, secret_length = (buf[2] << 8) + buf[3];
uint8_t premaster_secret[MAX_KEY_BYTE_SIZE];
RSA_CTX *rsa_ctx = ssl->ssl_ctx->rsa_ctx;
int offset = 4;
int ret = SSL_OK;
if (rsa_ctx == NULL)
{
ret = SSL_ERROR_NO_CERT_DEFINED;
goto error;
}
/* is there an extra size field? */
if ((secret_length - 2) == rsa_ctx->num_octets)
offset += 2;
PARANOIA_CHECK(pkt_size, rsa_ctx->num_octets+offset);
/* rsa_ctx->bi_ctx is not thread-safe */
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
premaster_size = RSA_decrypt(rsa_ctx, &buf[offset], premaster_secret,
sizeof(premaster_secret), 1);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
if (premaster_size != SSL_SECRET_SIZE ||
premaster_secret[0] != 0x03 || /* must be the same as client
offered version */
premaster_secret[1] != (ssl->client_version & 0x0f))
{
/* guard against a Bleichenbacher attack */
if (get_random(SSL_SECRET_SIZE, premaster_secret) < 0)
return SSL_NOT_OK;
/* and continue - will die eventually when checking the mac */
}
#if 0
print_blob("pre-master", premaster_secret, SSL_SECRET_SIZE);
#endif
generate_master_secret(ssl, premaster_secret);
#ifdef CONFIG_SSL_CERT_VERIFICATION
ssl->next_state = IS_SET_SSL_FLAG(SSL_CLIENT_AUTHENTICATION) ?
HS_CERT_VERIFY : HS_FINISHED;
#else
ssl->next_state = HS_FINISHED;
#endif
ssl->dc->bm_proc_index += rsa_ctx->num_octets+offset;
error:
return ret;
}
/*
* Process a client hello message.
*/
static int process_client_hello(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
uint8_t *record_buf = ssl->hmac_header;
int pkt_size = ssl->bm_index;
int i, j, cs_len, id_len, offset = 6 + SSL_RANDOM_SIZE;
int version = (record_buf[1] << 4) + record_buf[2];
int ret = SSL_OK;
/* should be v3.1 (TLSv1) or better - we'll send in v3.1 mode anyway */
if (version < 0x31)
{
ret = SSL_ERROR_INVALID_VERSION;
ssl_display_error(ret);
goto error;
}
memcpy(ssl->dc->client_random, &buf[6], SSL_RANDOM_SIZE);
/* process the session id */
id_len = buf[offset++];
if (id_len > SSL_SESSION_ID_SIZE)
{
return SSL_ERROR_INVALID_SESSION;
}
#ifndef CONFIG_SSL_SKELETON_MODE
ssl->session = ssl_session_update(ssl->ssl_ctx->num_sessions,
ssl->ssl_ctx->ssl_sessions, ssl, id_len ? &buf[offset] : NULL);
#endif
offset += id_len;
cs_len = (buf[offset]<<8) + buf[offset+1];
offset += 3; /* add 1 due to all cipher suites being 8 bit */
PARANOIA_CHECK(pkt_size, offset);
/* work out what cipher suite we are going to use */
for (j = 0; j < NUM_PROTOCOLS; j++)
{
for (i = 0; i < cs_len; i += 2)
{
if (ssl_prot_prefs[j] == buf[offset+i]) /* got a match? */
{
ssl->cipher = ssl_prot_prefs[j];
goto do_state;
}
}
}
/* ouch! protocol is not supported */
ret = SSL_ERROR_NO_CIPHER;
do_state:
error:
return ret;
}
/*
* Process a client hello message.
*/
static int ICACHE_FLASH_ATTR process_client_hello(SSL *ssl) {
uint8_t *buf = ssl->bm_data;
uint8_t *record_buf = ssl->hmac_header;
int pkt_size = ssl->bm_index;
int i, j, cs_len, id_len, offset = 6 + SSL_RANDOM_SIZE;
int ret = SSL_OK;
uint8_t version = (buf[4] << 4) + buf[5];
ssl->version = ssl->client_version = version;
if (version > SSL_PROTOCOL_VERSION_MAX) {
/* use client's version instead */
ssl->version = SSL_PROTOCOL_VERSION_MAX;
} else if (version < SSL_PROTOCOL_MIN_VERSION) { /* old version supported? */
ret = SSL_ERROR_INVALID_VERSION;
//ssl_display_error(ret);
goto error;
}
os_memcpy(ssl->dc->client_random, &buf[6], SSL_RANDOM_SIZE);
/* process the session id */
id_len = buf[offset++];
if (id_len > SSL_SESSION_ID_SIZE) {
return SSL_ERROR_INVALID_SESSION;
}
#ifndef CONFIG_SSL_SKELETON_MODE
ssl->session = ssl_session_update(ssl->ssl_ctx->num_sessions,
ssl->ssl_ctx->ssl_sessions, ssl, id_len ? &buf[offset] : NULL);
#endif
offset += id_len;
cs_len = (buf[offset] << 8) + buf[offset + 1];
offset += 2; /* add 1 due to all cipher suites being 8 bit */
PARANOIA_CHECK(pkt_size, offset);
/* work out what cipher suite we are going to use - client defines
the preference */
for (i = 0; i < cs_len; i += 2) {
for (j = 0; j < NUM_PROTOCOLS; j++) {
if (ssl_prot_prefs[j] == ((buf[offset + i] << 8) + buf[offset + i + 1])) { /* got a match? */
ssl->cipher = ssl_prot_prefs[j];
goto do_state;
}
}
}
/* ouch! protocol is not supported */
ret = SSL_ERROR_NO_CIPHER;
do_state:
error:
return ret;
}
/*
* Process the certificate request.
*/
static int ICACHE_FLASH_ATTR 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;
}
/*
* Process the server hello.
*/
static int ICACHE_FLASH_ATTR 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;
}
/*
* Ensure the client has the private key by first decrypting the packet and
* then checking the packet digests.
*/
static int process_cert_verify(SSL *ssl)
{
uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
int pkt_size = ssl->bm_index;
uint8_t dgst_buf[MAX_KEY_BYTE_SIZE];
uint8_t dgst[MD5_SIZE + SHA1_SIZE];
X509_CTX *x509_ctx = ssl->x509_ctx;
int ret = SSL_OK;
int offset = 6;
int rsa_len;
int n;
DISPLAY_RSA(ssl, x509_ctx->rsa_ctx);
if (ssl->version >= SSL_PROTOCOL_VERSION_TLS1_2) // TLS1.2+
{
// TODO: should really need to be able to handle other algorihms. An
// assumption is made on RSA/SHA256 and appears to be OK.
//uint8_t hash_alg = buf[4];
//uint8_t sig_alg = buf[5];
offset = 8;
rsa_len = (buf[6] << 8) + buf[7];
}
else
{
rsa_len = (buf[4] << 8) + buf[5];
}
PARANOIA_CHECK(pkt_size, offset + rsa_len);
/* rsa_ctx->bi_ctx is not thread-safe */
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
n = RSA_decrypt(x509_ctx->rsa_ctx, &buf[offset], dgst_buf,
sizeof(dgst_buf), 0);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
if (ssl->version >= SSL_PROTOCOL_VERSION_TLS1_2) // TLS1.2+
{
if (memcmp(dgst_buf, g_asn1_sha256, sizeof(g_asn1_sha256)))
{
ret = SSL_ERROR_INVALID_KEY;
goto error;
}
finished_digest(ssl, NULL, dgst); /* calculate the digest */
if (memcmp(&dgst_buf[sizeof(g_asn1_sha256)], dgst, SHA256_SIZE))
{
ret = SSL_ERROR_INVALID_KEY;
goto error;
}
}
else // TLS1.0/1.1
{
if (n != SHA1_SIZE + MD5_SIZE)
{
ret = SSL_ERROR_INVALID_KEY;
goto end_cert_vfy;
}
finished_digest(ssl, NULL, dgst); /* calculate the digest */
if (memcmp(dgst_buf, dgst, MD5_SIZE + SHA1_SIZE))
{
ret = SSL_ERROR_INVALID_KEY;
}
}
end_cert_vfy:
ssl->next_state = HS_FINISHED;
error:
return ret;
}
/*
* Process a client hello message.
*/
static int process_client_hello(SSL *ssl)
{
uint8_t *buf = ssl->bm_data;
int pkt_size = ssl->bm_index;
int i, j, cs_len, id_len, offset = 6 + SSL_RANDOM_SIZE;
int ret = SSL_OK;
uint8_t version = (buf[4] << 4) + buf[5];
ssl->version = ssl->client_version = version;
if (version > SSL_PROTOCOL_VERSION_MAX)
{
/* use client's version instead */
ssl->version = SSL_PROTOCOL_VERSION_MAX;
}
else if (version < SSL_PROTOCOL_MIN_VERSION) /* old version supported? */
{
ret = SSL_ERROR_INVALID_VERSION;
#ifdef CONFIG_SSL_DIAGNOSTICS
ssl_display_error(ret);
#endif
goto error;
}
memcpy(ssl->dc->client_random, &buf[6], SSL_RANDOM_SIZE);
/* process the session id */
id_len = buf[offset++];
if (id_len > SSL_SESSION_ID_SIZE)
{
return SSL_ERROR_INVALID_SESSION;
}
#ifndef CONFIG_SSL_SKELETON_MODE
ssl->session = ssl_session_update(ssl->ssl_ctx->num_sessions,
ssl->ssl_ctx->ssl_sessions, ssl, id_len ? &buf[offset] : NULL);
#endif
offset += id_len;
cs_len = (buf[offset]<<8) + buf[offset+1];
offset += 3; /* add 1 due to all cipher suites being 8 bit */
PARANOIA_CHECK(pkt_size, offset + cs_len);
/* work out what cipher suite we are going to use - client defines
the preference */
for (i = 0; i < cs_len; i += 2)
{
for (j = 0; j < NUM_PROTOCOLS; j++)
{
if (ssl_prot_prefs[j] == buf[offset+i]) /* got a match? */
{
ssl->cipher = ssl_prot_prefs[j];
goto do_compression;
}
}
}
/* ouch! protocol is not supported */
return SSL_ERROR_NO_CIPHER;
/* completely ignore compression */
do_compression:
offset += cs_len;
id_len = buf[offset++];
offset += id_len;
PARANOIA_CHECK(pkt_size, offset + id_len);
if (offset == pkt_size)
{
/* no extensions */
goto error;
}
/* extension size */
id_len = buf[offset++] << 8;
id_len += buf[offset++];
PARANOIA_CHECK(pkt_size, offset + id_len);
// Check for extensions from the client - only the signature algorithm
// is supported
while (offset < pkt_size)
{
int ext = buf[offset++] << 8;
ext += buf[offset++];
int ext_len = buf[offset++] << 8;
ext_len += buf[offset++];
PARANOIA_CHECK(pkt_size, offset + ext_len);
if (ext == SSL_EXT_SIG_ALG)
{
while (ext_len > 0)
{
uint8_t hash_alg = buf[offset++];
uint8_t sig_alg = buf[offset++];
ext_len -= 2;
if (sig_alg == SIG_ALG_RSA &&
(hash_alg == SIG_ALG_SHA1 ||
hash_alg == SIG_ALG_SHA256 ||
hash_alg == SIG_ALG_SHA384 ||
hash_alg == SIG_ALG_SHA512))
{
ssl->sig_algs[ssl->num_sig_algs++] = hash_alg;
}
}
}
else
{
offset += ext_len;
}
}
/* default is RSA/SHA1 */
if (ssl->num_sig_algs == 0)
{
ssl->sig_algs[ssl->num_sig_algs++] = SIG_ALG_SHA1;
}
error:
return ret;
}