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openssl/ssl/statem/statem.c
Matt Caswell e158ada6a7 Remove the old buffer management code 
We no longer use the old buffer management code now that it has all been
moved to the new record layer.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19424)
2022-10-20 14:39:33 +01:00

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/*
* Copyright 2015-2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#if defined(__TANDEM) && defined(_SPT_MODEL_)
# include <spthread.h>
# include <spt_extensions.h> /* timeval */
#endif
#include "internal/cryptlib.h"
#include <openssl/rand.h>
#include "../ssl_local.h"
#include "statem_local.h"
#include <assert.h>
/*
* This file implements the SSL/TLS/DTLS state machines.
*
* There are two primary state machines:
*
* 1) Message flow state machine
* 2) Handshake state machine
*
* The Message flow state machine controls the reading and sending of messages
* including handling of non-blocking IO events, flushing of the underlying
* write BIO, handling unexpected messages, etc. It is itself broken into two
* separate sub-state machines which control reading and writing respectively.
*
* The Handshake state machine keeps track of the current SSL/TLS handshake
* state. Transitions of the handshake state are the result of events that
* occur within the Message flow state machine.
*
* Overall it looks like this:
*
* --------------------------------------------- -------------------
* | | | |
* | Message flow state machine | | |
* | | | |
* | -------------------- -------------------- | Transition | Handshake state |
* | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine |
* | | sub-state | | sub-state | |----------->| |
* | | machine for | | machine for | | | |
* | | reading messages | | writing messages | | | |
* | -------------------- -------------------- | | |
* | | | |
* --------------------------------------------- -------------------
*
*/
/* Sub state machine return values */
typedef enum {
/* Something bad happened or NBIO */
SUB_STATE_ERROR,
/* Sub state finished go to the next sub state */
SUB_STATE_FINISHED,
/* Sub state finished and handshake was completed */
SUB_STATE_END_HANDSHAKE
} SUB_STATE_RETURN;
static int state_machine(SSL_CONNECTION *s, int server);
static void init_read_state_machine(SSL_CONNECTION *s);
static SUB_STATE_RETURN read_state_machine(SSL_CONNECTION *s);
static void init_write_state_machine(SSL_CONNECTION *s);
static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s);
OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl)
{
const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(ssl);
if (sc == NULL)
return TLS_ST_BEFORE;
return sc->statem.hand_state;
}
int SSL_in_init(const SSL *s)
{
const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
if (sc == NULL)
return 0;
return sc->statem.in_init;
}
int SSL_is_init_finished(const SSL *s)
{
const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
if (sc == NULL)
return 0;
return !(sc->statem.in_init) && (sc->statem.hand_state == TLS_ST_OK);
}
int SSL_in_before(const SSL *s)
{
const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);
if (sc == NULL)
return 0;
/*
* Historically being "in before" meant before anything had happened. In the
* current code though we remain in the "before" state for a while after we
* have started the handshake process (e.g. as a server waiting for the
* first message to arrive). There "in before" is taken to mean "in before"
* and not started any handshake process yet.
*/
return (sc->statem.hand_state == TLS_ST_BEFORE)
&& (sc->statem.state == MSG_FLOW_UNINITED);
}
OSSL_HANDSHAKE_STATE ossl_statem_get_state(SSL_CONNECTION *s)
{
return s != NULL ? s->statem.hand_state : TLS_ST_BEFORE;
}
/*
* Clear the state machine state and reset back to MSG_FLOW_UNINITED
*/
void ossl_statem_clear(SSL_CONNECTION *s)
{
s->statem.state = MSG_FLOW_UNINITED;
s->statem.hand_state = TLS_ST_BEFORE;
ossl_statem_set_in_init(s, 1);
s->statem.no_cert_verify = 0;
}
/*
* Set the state machine up ready for a renegotiation handshake
*/
void ossl_statem_set_renegotiate(SSL_CONNECTION *s)
{
ossl_statem_set_in_init(s, 1);
s->statem.request_state = TLS_ST_SW_HELLO_REQ;
}
void ossl_statem_send_fatal(SSL_CONNECTION *s, int al)
{
/* We shouldn't call SSLfatal() twice. Once is enough */
if (s->statem.in_init && s->statem.state == MSG_FLOW_ERROR)
return;
ossl_statem_set_in_init(s, 1);
s->statem.state = MSG_FLOW_ERROR;
if (al != SSL_AD_NO_ALERT)
ssl3_send_alert(s, SSL3_AL_FATAL, al);
}
/*
* Error reporting building block that's used instead of ERR_set_error().
* In addition to what ERR_set_error() does, this puts the state machine
* into an error state and sends an alert if appropriate.
* This is a permanent error for the current connection.
*/
void ossl_statem_fatal(SSL_CONNECTION *s, int al, int reason,
const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
ERR_vset_error(ERR_LIB_SSL, reason, fmt, args);
va_end(args);
ossl_statem_send_fatal(s, al);
}
/*
* This macro should only be called if we are already expecting to be in
* a fatal error state. We verify that we are, and set it if not (this would
* indicate a bug).
*/
#define check_fatal(s) \
do { \
if (!ossl_assert((s)->statem.in_init \
&& (s)->statem.state == MSG_FLOW_ERROR)) \
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_MISSING_FATAL); \
} while (0)
/*
* Discover whether the current connection is in the error state.
*
* Valid return values are:
* 1: Yes
* 0: No
*/
int ossl_statem_in_error(const SSL_CONNECTION *s)
{
if (s->statem.state == MSG_FLOW_ERROR)
return 1;
return 0;
}
void ossl_statem_set_in_init(SSL_CONNECTION *s, int init)
{
s->statem.in_init = init;
if (s->rlayer.rrlmethod != NULL && s->rlayer.rrlmethod->set_in_init != NULL)
s->rlayer.rrlmethod->set_in_init(s->rlayer.rrl, init);
}
int ossl_statem_get_in_handshake(SSL_CONNECTION *s)
{
return s->statem.in_handshake;
}
void ossl_statem_set_in_handshake(SSL_CONNECTION *s, int inhand)
{
if (inhand)
s->statem.in_handshake++;
else
s->statem.in_handshake--;
}
/* Are we in a sensible state to skip over unreadable early data? */
int ossl_statem_skip_early_data(SSL_CONNECTION *s)
{
if (s->ext.early_data != SSL_EARLY_DATA_REJECTED)
return 0;
if (!s->server
|| s->statem.hand_state != TLS_ST_EARLY_DATA
|| s->hello_retry_request == SSL_HRR_COMPLETE)
return 0;
return 1;
}
/*
* Called when we are in SSL_read*(), SSL_write*(), or SSL_accept()
* /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early
* data state and whether we should attempt to move the handshake on if so.
* |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are
* attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake()
* or similar.
*/
void ossl_statem_check_finish_init(SSL_CONNECTION *s, int sending)
{
if (sending == -1) {
if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
|| s->statem.hand_state == TLS_ST_EARLY_DATA) {
ossl_statem_set_in_init(s, 1);
if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
/*
* SSL_connect() or SSL_do_handshake() has been called directly.
* We don't allow any more writing of early data.
*/
s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
}
}
} else if (!s->server) {
if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
|| s->statem.hand_state == TLS_ST_EARLY_DATA)
&& s->early_data_state != SSL_EARLY_DATA_WRITING)
|| (!sending && s->statem.hand_state == TLS_ST_EARLY_DATA)) {
ossl_statem_set_in_init(s, 1);
/*
* SSL_write() has been called directly. We don't allow any more
* writing of early data.
*/
if (sending && s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY)
s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
}
} else {
if (s->early_data_state == SSL_EARLY_DATA_FINISHED_READING
&& s->statem.hand_state == TLS_ST_EARLY_DATA)
ossl_statem_set_in_init(s, 1);
}
}
void ossl_statem_set_hello_verify_done(SSL_CONNECTION *s)
{
s->statem.state = MSG_FLOW_UNINITED;
ossl_statem_set_in_init(s, 1);
/*
* This will get reset (briefly) back to TLS_ST_BEFORE when we enter
* state_machine() because |state| is MSG_FLOW_UNINITED, but until then any
* calls to SSL_in_before() will return false. Also calls to
* SSL_state_string() and SSL_state_string_long() will return something
* sensible.
*/
s->statem.hand_state = TLS_ST_SR_CLNT_HELLO;
}
int ossl_statem_connect(SSL *s)
{
SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
if (sc == NULL)
return -1;
return state_machine(sc, 0);
}
int ossl_statem_accept(SSL *s)
{
SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
if (sc == NULL)
return -1;
return state_machine(sc, 1);
}
typedef void (*info_cb) (const SSL *, int, int);
static info_cb get_callback(SSL_CONNECTION *s)
{
SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
if (s->info_callback != NULL)
return s->info_callback;
else if (sctx->info_callback != NULL)
return sctx->info_callback;
return NULL;
}
/*
* The main message flow state machine. We start in the MSG_FLOW_UNINITED or
* MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and
* transitions are as follows:
*
* MSG_FLOW_UNINITED MSG_FLOW_FINISHED
* | |
* +-----------------------+
* v
* MSG_FLOW_WRITING <---> MSG_FLOW_READING
* |
* V
* MSG_FLOW_FINISHED
* |
* V
* [SUCCESS]
*
* We may exit at any point due to an error or NBIO event. If an NBIO event
* occurs then we restart at the point we left off when we are recalled.
* MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them.
*
* In addition to the above there is also the MSG_FLOW_ERROR state. We can move
* into that state at any point in the event that an irrecoverable error occurs.
*
* Valid return values are:
* 1: Success
* <=0: NBIO or error
*/
static int state_machine(SSL_CONNECTION *s, int server)
{
BUF_MEM *buf = NULL;
void (*cb) (const SSL *ssl, int type, int val) = NULL;
OSSL_STATEM *st = &s->statem;
int ret = -1;
int ssret;
SSL *ssl = SSL_CONNECTION_GET_SSL(s);
if (st->state == MSG_FLOW_ERROR) {
/* Shouldn't have been called if we're already in the error state */
return -1;
}
ERR_clear_error();
clear_sys_error();
cb = get_callback(s);
st->in_handshake++;
if (!SSL_in_init(ssl) || SSL_in_before(ssl)) {
/*
* If we are stateless then we already called SSL_clear() - don't do
* it again and clear the STATELESS flag itself.
*/
if ((s->s3.flags & TLS1_FLAGS_STATELESS) == 0 && !SSL_clear(ssl))
return -1;
}
#ifndef OPENSSL_NO_SCTP
if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
/*
* Notify SCTP BIO socket to enter handshake mode and prevent stream
* identifier other than 0.
*/
BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
st->in_handshake, NULL);
}
#endif
/* Initialise state machine */
if (st->state == MSG_FLOW_UNINITED
|| st->state == MSG_FLOW_FINISHED) {
if (st->state == MSG_FLOW_UNINITED) {
st->hand_state = TLS_ST_BEFORE;
st->request_state = TLS_ST_BEFORE;
}
s->server = server;
if (cb != NULL) {
if (SSL_IS_FIRST_HANDSHAKE(s) || !SSL_CONNECTION_IS_TLS13(s))
cb(ssl, SSL_CB_HANDSHAKE_START, 1);
}
/*
* Fatal errors in this block don't send an alert because we have
* failed to even initialise properly. Sending an alert is probably
* doomed to failure.
*/
if (SSL_CONNECTION_IS_DTLS(s)) {
if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) &&
(server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
} else {
if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
}
if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
if (s->init_buf == NULL) {
if ((buf = BUF_MEM_new()) == NULL) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
s->init_buf = buf;
buf = NULL;
}
s->init_num = 0;
/*
* Should have been reset by tls_process_finished, too.
*/
s->s3.change_cipher_spec = 0;
/*
* Ok, we now need to push on a buffering BIO ...but not with
* SCTP
*/
#ifndef OPENSSL_NO_SCTP
if (!SSL_CONNECTION_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(ssl)))
#endif
if (!ssl_init_wbio_buffer(s)) {
SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
goto end;
}
if ((SSL_in_before(ssl))
|| s->renegotiate) {
if (!tls_setup_handshake(s)) {
/* SSLfatal() already called */
goto end;
}
if (SSL_IS_FIRST_HANDSHAKE(s))
st->read_state_first_init = 1;
}
st->state = MSG_FLOW_WRITING;
init_write_state_machine(s);
}
while (st->state != MSG_FLOW_FINISHED) {
if (st->state == MSG_FLOW_READING) {
ssret = read_state_machine(s);
if (ssret == SUB_STATE_FINISHED) {
st->state = MSG_FLOW_WRITING;
init_write_state_machine(s);
} else {
/* NBIO or error */
goto end;
}
} else if (st->state == MSG_FLOW_WRITING) {
ssret = write_state_machine(s);
if (ssret == SUB_STATE_FINISHED) {
st->state = MSG_FLOW_READING;
init_read_state_machine(s);
} else if (ssret == SUB_STATE_END_HANDSHAKE) {
st->state = MSG_FLOW_FINISHED;
} else {
/* NBIO or error */
goto end;
}
} else {
/* Error */
check_fatal(s);
ERR_raise(ERR_LIB_SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
goto end;
}
}
ret = 1;
end:
st->in_handshake--;
#ifndef OPENSSL_NO_SCTP
if (SSL_CONNECTION_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
/*
* Notify SCTP BIO socket to leave handshake mode and allow stream
* identifier other than 0.
*/
BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
st->in_handshake, NULL);
}
#endif
BUF_MEM_free(buf);
if (cb != NULL) {
if (server)
cb(ssl, SSL_CB_ACCEPT_EXIT, ret);
else
cb(ssl, SSL_CB_CONNECT_EXIT, ret);
}
return ret;
}
/*
* Initialise the MSG_FLOW_READING sub-state machine
*/
static void init_read_state_machine(SSL_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
st->read_state = READ_STATE_HEADER;
}
static int grow_init_buf(SSL_CONNECTION *s, size_t size) {
size_t msg_offset = (char *)s->init_msg - s->init_buf->data;
if (!BUF_MEM_grow_clean(s->init_buf, (int)size))
return 0;
if (size < msg_offset)
return 0;
s->init_msg = s->init_buf->data + msg_offset;
return 1;
}
/*
* 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_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
int ret, mt;
size_t len = 0;
int (*transition) (SSL_CONNECTION *s, int mt);
PACKET pkt;
MSG_PROCESS_RETURN(*process_message) (SSL_CONNECTION *s, PACKET *pkt);
WORK_STATE(*post_process_message) (SSL_CONNECTION *s, WORK_STATE wst);
size_t (*max_message_size) (SSL_CONNECTION *s);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
SSL *ssl = SSL_CONNECTION_GET_SSL(s);
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_CONNECTION_IS_DTLS(s)) {
/*
* In DTLS we get the whole message in one go - header and body
*/
ret = dtls_get_message(s, &mt);
} 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(ssl, SSL_CB_ACCEPT_LOOP, 1);
else
cb(ssl, 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))
return SUB_STATE_ERROR;
if (s->s3.tmp.message_size > max_message_size(s)) {
SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SUB_STATE_ERROR;
}
/* dtls_get_message already did this */
if (!SSL_CONNECTION_IS_DTLS(s)
&& s->s3.tmp.message_size > 0
&& !grow_init_buf(s, s->s3.tmp.message_size
+ SSL3_HM_HEADER_LENGTH)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_BUF_LIB);
return SUB_STATE_ERROR;
}
st->read_state = READ_STATE_BODY;
/* Fall through */
case READ_STATE_BODY:
if (SSL_CONNECTION_IS_DTLS(s)) {
/*
* Actually we already have the body, but we give DTLS the
* opportunity to do any further processing.
*/
ret = dtls_get_message_body(s, &len);
} else {
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)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, 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:
check_fatal(s);
return SUB_STATE_ERROR;
case MSG_PROCESS_FINISHED_READING:
if (SSL_CONNECTION_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) {
case WORK_ERROR:
check_fatal(s);
/* Fall through */
case WORK_MORE_A:
case WORK_MORE_B:
case WORK_MORE_C:
return SUB_STATE_ERROR;
case WORK_FINISHED_CONTINUE:
st->read_state = READ_STATE_HEADER;
break;
case WORK_FINISHED_STOP:
if (SSL_CONNECTION_IS_DTLS(s)) {
dtls1_stop_timer(s);
}
return SUB_STATE_FINISHED;
}
break;
default:
/* Shouldn't happen */
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return SUB_STATE_ERROR;
}
}
}
/*
* Send a previously constructed message to the peer.
*/
static int statem_do_write(SSL_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
if (st->hand_state == TLS_ST_CW_CHANGE
|| st->hand_state == TLS_ST_SW_CHANGE) {
if (SSL_CONNECTION_IS_DTLS(s))
return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
else
return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
} else {
return ssl_do_write(s);
}
}
/*
* Initialise the MSG_FLOW_WRITING sub-state machine
*/
static void init_write_state_machine(SSL_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
st->write_state = WRITE_STATE_TRANSITION;
}
/*
* This function implements the sub-state machine when the message flow is in
* MSG_FLOW_WRITING. The valid sub-states and transitions are:
*
* +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED]
* | |
* | v
* | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE]
* | |
* | v
* | WRITE_STATE_SEND
* | |
* | v
* | WRITE_STATE_POST_WORK
* | |
* +-------------+
*
* WRITE_STATE_TRANSITION transitions the state of the handshake state machine
* WRITE_STATE_PRE_WORK performs any work necessary to prepare the later
* sending of the message. This 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.
*
* WRITE_STATE_SEND sends the message and performs any work to be done after
* sending.
*
* WRITE_STATE_POST_WORK performs any work necessary after the sending of the
* message has been completed. As for WRITE_STATE_PRE_WORK this could also
* result in an NBIO event.
*/
static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
int ret;
WRITE_TRAN(*transition) (SSL_CONNECTION *s);
WORK_STATE(*pre_work) (SSL_CONNECTION *s, WORK_STATE wst);
WORK_STATE(*post_work) (SSL_CONNECTION *s, WORK_STATE wst);
int (*get_construct_message_f) (SSL_CONNECTION *s,
CON_FUNC_RETURN (**confunc) (SSL_CONNECTION *s,
WPACKET *pkt),
int *mt);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
CON_FUNC_RETURN (*confunc) (SSL_CONNECTION *s, WPACKET *pkt);
int mt;
WPACKET pkt;
SSL *ssl = SSL_CONNECTION_GET_SSL(s);
cb = get_callback(s);
if (s->server) {
transition = ossl_statem_server_write_transition;
pre_work = ossl_statem_server_pre_work;
post_work = ossl_statem_server_post_work;
get_construct_message_f = ossl_statem_server_construct_message;
} else {
transition = ossl_statem_client_write_transition;
pre_work = ossl_statem_client_pre_work;
post_work = ossl_statem_client_post_work;
get_construct_message_f = ossl_statem_client_construct_message;
}
while (1) {
switch (st->write_state) {
case WRITE_STATE_TRANSITION:
if (cb != NULL) {
/* Notify callback of an impending state change */
if (s->server)
cb(ssl, SSL_CB_ACCEPT_LOOP, 1);
else
cb(ssl, SSL_CB_CONNECT_LOOP, 1);
}
switch (transition(s)) {
case WRITE_TRAN_CONTINUE:
st->write_state = WRITE_STATE_PRE_WORK;
st->write_state_work = WORK_MORE_A;
break;
case WRITE_TRAN_FINISHED:
return SUB_STATE_FINISHED;
break;
case WRITE_TRAN_ERROR:
check_fatal(s);
return SUB_STATE_ERROR;
}
break;
case WRITE_STATE_PRE_WORK:
switch (st->write_state_work = pre_work(s, st->write_state_work)) {
case WORK_ERROR:
check_fatal(s);
/* Fall through */
case WORK_MORE_A:
case WORK_MORE_B:
case WORK_MORE_C:
return SUB_STATE_ERROR;
case WORK_FINISHED_CONTINUE:
st->write_state = WRITE_STATE_SEND;
break;
case WORK_FINISHED_STOP:
return SUB_STATE_END_HANDSHAKE;
}
if (!get_construct_message_f(s, &confunc, &mt)) {
/* SSLfatal() already called */
return SUB_STATE_ERROR;
}
if (mt == SSL3_MT_DUMMY) {
/* Skip construction and sending. This isn't a "real" state */
st->write_state = WRITE_STATE_POST_WORK;
st->write_state_work = WORK_MORE_A;
break;
}
if (!WPACKET_init(&pkt, s->init_buf)
|| !ssl_set_handshake_header(s, &pkt, mt)) {
WPACKET_cleanup(&pkt);
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return SUB_STATE_ERROR;
}
if (confunc != NULL) {
CON_FUNC_RETURN tmpret;
tmpret = confunc(s, &pkt);
if (tmpret == CON_FUNC_ERROR) {
WPACKET_cleanup(&pkt);
check_fatal(s);
return SUB_STATE_ERROR;
} else if (tmpret == CON_FUNC_DONT_SEND) {
/*
* The construction function decided not to construct the
* message after all and continue. Skip sending.
*/
WPACKET_cleanup(&pkt);
st->write_state = WRITE_STATE_POST_WORK;
st->write_state_work = WORK_MORE_A;
break;
} /* else success */
}
if (!ssl_close_construct_packet(s, &pkt, mt)
|| !WPACKET_finish(&pkt)) {
WPACKET_cleanup(&pkt);
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return SUB_STATE_ERROR;
}
/* Fall through */
case WRITE_STATE_SEND:
if (SSL_CONNECTION_IS_DTLS(s) && st->use_timer) {
dtls1_start_timer(s);
}
ret = statem_do_write(s);
if (ret <= 0) {
return SUB_STATE_ERROR;
}
st->write_state = WRITE_STATE_POST_WORK;
st->write_state_work = WORK_MORE_A;
/* Fall through */
case WRITE_STATE_POST_WORK:
switch (st->write_state_work = post_work(s, st->write_state_work)) {
case WORK_ERROR:
check_fatal(s);
/* Fall through */
case WORK_MORE_A:
case WORK_MORE_B:
case WORK_MORE_C:
return SUB_STATE_ERROR;
case WORK_FINISHED_CONTINUE:
st->write_state = WRITE_STATE_TRANSITION;
break;
case WORK_FINISHED_STOP:
return SUB_STATE_END_HANDSHAKE;
}
break;
default:
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return SUB_STATE_ERROR;
}
}
}
/*
* Flush the write BIO
*/
int statem_flush(SSL_CONNECTION *s)
{
s->rwstate = SSL_WRITING;
if (BIO_flush(s->wbio) <= 0) {
return 0;
}
s->rwstate = SSL_NOTHING;
return 1;
}
/*
* Called by the record layer to determine whether application data is
* allowed to be received in the current handshake state or not.
*
* Return values are:
* 1: Yes (application data allowed)
* 0: No (application data not allowed)
*/
int ossl_statem_app_data_allowed(SSL_CONNECTION *s)
{
OSSL_STATEM *st = &s->statem;
if (st->state == MSG_FLOW_UNINITED)
return 0;
if (!s->s3.in_read_app_data || (s->s3.total_renegotiations == 0))
return 0;
if (s->server) {
/*
* If we're a server and we haven't got as far as writing our
* ServerHello yet then we allow app data
*/
if (st->hand_state == TLS_ST_BEFORE
|| st->hand_state == TLS_ST_SR_CLNT_HELLO)
return 1;
} else {
/*
* If we're a client and we haven't read the ServerHello yet then we
* allow app data
*/
if (st->hand_state == TLS_ST_CW_CLNT_HELLO)
return 1;
}
return 0;
}
/*
* This function returns 1 if TLS exporter is ready to export keying
* material, or 0 if otherwise.
*/
int ossl_statem_export_allowed(SSL_CONNECTION *s)
{
return s->s3.previous_server_finished_len != 0
&& s->statem.hand_state != TLS_ST_SW_FINISHED;
}
/*
* Return 1 if early TLS exporter is ready to export keying material,
* or 0 if otherwise.
*/
int ossl_statem_export_early_allowed(SSL_CONNECTION *s)
{
/*
* The early exporter secret is only present on the server if we
* have accepted early_data. It is present on the client as long
* as we have sent early_data.
*/
return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED
|| (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT);
}
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