/*
* This function implements the sub-state machine when the message flow is in
* MSG_FLOW_READING. The valid sub-states and transitions are:
*
* READ_STATE_HEADER <--+<-------------+
* | | |
* v | |
* READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS
* | |
* +----------------------------+
* v
* [SUB_STATE_FINISHED]
*
* READ_STATE_HEADER has the responsibility for reading in the message header
* and transitioning the state of the handshake state machine.
*
* READ_STATE_BODY reads in the rest of the message and then subsequently
* processes it.
*
* READ_STATE_POST_PROCESS is an optional step that may occur if some post
* processing activity performed on the message may block.
*
* Any of the above states could result in an NBIO event occurring in which case
* control returns to the calling application. When this function is recalled we
* will resume in the same state where we left off.
*/
static SUB_STATE_RETURN read_state_machine(SSL *s)
{
OSSL_STATEM *st = &s->statem;
int ret, mt;
unsigned long len = 0;
int (*transition) (SSL *s, int mt);
PACKET pkt;
MSG_PROCESS_RETURN(*process_message) (SSL *s, PACKET *pkt);
WORK_STATE(*post_process_message) (SSL *s, WORK_STATE wst);
unsigned long (*max_message_size) (SSL *s);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
cb = get_callback(s);
if (s->server) {
transition = ossl_statem_server_read_transition;
process_message = ossl_statem_server_process_message;
max_message_size = ossl_statem_server_max_message_size;
post_process_message = ossl_statem_server_post_process_message;
} else {
transition = ossl_statem_client_read_transition;
process_message = ossl_statem_client_process_message;
max_message_size = ossl_statem_client_max_message_size;
post_process_message = ossl_statem_client_post_process_message;
}
if (st->read_state_first_init) {
s->first_packet = 1;
st->read_state_first_init = 0;
}
while (1) {
switch (st->read_state) {
case READ_STATE_HEADER:
/* Get the state the peer wants to move to */
if (SSL_IS_DTLS(s)) {
/*
* In DTLS we get the whole message in one go - header and body
*/
ret = dtls_get_message(s, &mt, &len);
} else {
ret = tls_get_message_header(s, &mt);
}
if (ret == 0) {
/* Could be non-blocking IO */
return SUB_STATE_ERROR;
}
if (cb != NULL) {
/* Notify callback of an impending state change */
if (s->server)
cb(s, SSL_CB_ACCEPT_LOOP, 1);
else
cb(s, SSL_CB_CONNECT_LOOP, 1);
}
/*
* Validate that we are allowed to move to the new state and move
* to that state if so
*/
if (!transition(s, mt)) {
ossl_statem_set_error(s);
return SUB_STATE_ERROR;
}
if (s->s3->tmp.message_size > max_message_size(s)) {
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
SSLerr(SSL_F_READ_STATE_MACHINE, SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SUB_STATE_ERROR;
}
/* dtls_get_message already did this */
if (!SSL_IS_DTLS(s)
&& s->s3->tmp.message_size > 0
&& !grow_init_buf(s, s->s3->tmp.message_size
+ SSL3_HM_HEADER_LENGTH)) {
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
SSLerr(SSL_F_READ_STATE_MACHINE, ERR_R_BUF_LIB);
return SUB_STATE_ERROR;
}
st->read_state = READ_STATE_BODY;
/* Fall through */
case READ_STATE_BODY:
if (!SSL_IS_DTLS(s)) {
/* We already got this above for DTLS */
ret = tls_get_message_body(s, &len);
if (ret == 0) {
/* Could be non-blocking IO */
return SUB_STATE_ERROR;
}
}
s->first_packet = 0;
if (!PACKET_buf_init(&pkt, s->init_msg, len)) {
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
SSLerr(SSL_F_READ_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
return SUB_STATE_ERROR;
}
ret = process_message(s, &pkt);
/* Discard the packet data */
s->init_num = 0;
switch (ret) {
case MSG_PROCESS_ERROR:
return SUB_STATE_ERROR;
case MSG_PROCESS_FINISHED_READING:
if (SSL_IS_DTLS(s)) {
dtls1_stop_timer(s);
}
return SUB_STATE_FINISHED;
case MSG_PROCESS_CONTINUE_PROCESSING:
st->read_state = READ_STATE_POST_PROCESS;
st->read_state_work = WORK_MORE_A;
break;
default:
st->read_state = READ_STATE_HEADER;
break;
}
break;
case READ_STATE_POST_PROCESS:
st->read_state_work = post_process_message(s, st->read_state_work);
switch (st->read_state_work) {
default:
return SUB_STATE_ERROR;
case WORK_FINISHED_CONTINUE:
st->read_state = READ_STATE_HEADER;
break;
case WORK_FINISHED_STOP:
if (SSL_IS_DTLS(s)) {
dtls1_stop_timer(s);
}
return SUB_STATE_FINISHED;
}
break;
default:
/* Shouldn't happen */
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
SSLerr(SSL_F_READ_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
ossl_statem_set_error(s);
return SUB_STATE_ERROR;
}
}
}/*
* ossl_statem_client_read_transition() encapsulates the logic for the allowed
* handshake state transitions when the client is reading messages from the
* server. The message type that the server has sent is provided in |mt|. The
* current state is in |s->statem.hand_state|.
*
* Return values are:
* 1: Success (transition allowed)
* 0: Error (transition not allowed)
*/
int ossl_statem_client_read_transition(SSL *s, int mt)
{
OSSL_STATEM *st = &s->statem;
int ske_expected;
switch (st->hand_state) {
case TLS_ST_CW_CLNT_HELLO:
if (mt == SSL3_MT_SERVER_HELLO) {
st->hand_state = TLS_ST_CR_SRVR_HELLO;
return 1;
}
if (SSL_IS_DTLS(s)) {
if (mt == DTLS1_MT_HELLO_VERIFY_REQUEST) {
st->hand_state = DTLS_ST_CR_HELLO_VERIFY_REQUEST;
return 1;
}
}
break;
case TLS_ST_CR_SRVR_HELLO:
if (s->hit) {
if (s->tlsext_ticket_expected) {
if (mt == SSL3_MT_NEWSESSION_TICKET) {
st->hand_state = TLS_ST_CR_SESSION_TICKET;
return 1;
}
} else if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
st->hand_state = TLS_ST_CR_CHANGE;
return 1;
}
} else {
if (SSL_IS_DTLS(s) && mt == DTLS1_MT_HELLO_VERIFY_REQUEST) {
st->hand_state = DTLS_ST_CR_HELLO_VERIFY_REQUEST;
return 1;
} else if (s->version >= TLS1_VERSION
&& s->tls_session_secret_cb != NULL
&& s->session->tlsext_tick != NULL
&& mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
/*
* Normally, we can tell if the server is resuming the session
* from the session ID. EAP-FAST (RFC 4851), however, relies on
* the next server message after the ServerHello to determine if
* the server is resuming.
*/
s->hit = 1;
st->hand_state = TLS_ST_CR_CHANGE;
return 1;
} else if (!(s->s3->tmp.new_cipher->algorithm_auth
& (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
if (mt == SSL3_MT_CERTIFICATE) {
st->hand_state = TLS_ST_CR_CERT;
return 1;
}
} else {
ske_expected = key_exchange_expected(s);
/* SKE is optional for some PSK ciphersuites */
if (ske_expected
|| ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
&& mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
st->hand_state = TLS_ST_CR_KEY_EXCH;
return 1;
}
} else if (mt == SSL3_MT_CERTIFICATE_REQUEST
&& cert_req_allowed(s)) {
st->hand_state = TLS_ST_CR_CERT_REQ;
return 1;
} else if (mt == SSL3_MT_SERVER_DONE) {
st->hand_state = TLS_ST_CR_SRVR_DONE;
return 1;
}
}
}
break;
case TLS_ST_CR_CERT:
/*
* The CertificateStatus message is optional even if
* |tlsext_status_expected| is set
*/
if (s->tlsext_status_expected && mt == SSL3_MT_CERTIFICATE_STATUS) {
st->hand_state = TLS_ST_CR_CERT_STATUS;
return 1;
}
/* Fall through */
case TLS_ST_CR_CERT_STATUS:
ske_expected = key_exchange_expected(s);
/* SKE is optional for some PSK ciphersuites */
if (ske_expected || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
&& mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
st->hand_state = TLS_ST_CR_KEY_EXCH;
return 1;
}
goto err;
}
/* Fall through */
case TLS_ST_CR_KEY_EXCH:
if (mt == SSL3_MT_CERTIFICATE_REQUEST) {
if (cert_req_allowed(s)) {
st->hand_state = TLS_ST_CR_CERT_REQ;
return 1;
}
goto err;
}
/* Fall through */
case TLS_ST_CR_CERT_REQ:
if (mt == SSL3_MT_SERVER_DONE) {
st->hand_state = TLS_ST_CR_SRVR_DONE;
return 1;
}
break;
case TLS_ST_CW_FINISHED:
if (s->tlsext_ticket_expected) {
if (mt == SSL3_MT_NEWSESSION_TICKET) {
st->hand_state = TLS_ST_CR_SESSION_TICKET;
return 1;
}
} else if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
st->hand_state = TLS_ST_CR_CHANGE;
return 1;
}
break;
case TLS_ST_CR_SESSION_TICKET:
if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
st->hand_state = TLS_ST_CR_CHANGE;
return 1;
}
break;
case TLS_ST_CR_CHANGE:
if (mt == SSL3_MT_FINISHED) {
st->hand_state = TLS_ST_CR_FINISHED;
return 1;
}
break;
default:
break;
}
err:
/* No valid transition found */
ssl3_send_alert(s, SSL3_AL_FATAL, SSL3_AD_UNEXPECTED_MESSAGE);
SSLerr(SSL_F_OSSL_STATEM_CLIENT_READ_TRANSITION, SSL_R_UNEXPECTED_MESSAGE);
return 0;
}更多推荐
openssl read_state_machine
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