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openssl/ssl/statem.c
Matt Caswell c64359db8a Redefine old state values 
ssl.h and ssl3.h have a number of defines for the various states in the old
state machine code. Since this is public API it is not desirable to just
remove them. Instead redefine them to the closest equivalent state in the
new state machine code. If an application calls SSL_state then the return
value can still be compared against these old values if necessary. However
not all values have an equivalent state in the new code, so these are just
redefined to a dummy value.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
2015-10-30 08:38:18 +00:00

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/* ssl/statem.c */
/*
* Written by Matt Caswell for the OpenSSL project.
*/
/* ====================================================================
* Copyright (c) 1998-2015 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED 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 OpenSSL PROJECT OR
* ITS 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.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#include <openssl/rand.h>
#include "ssl_locl.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 */
enum SUB_STATE_RETURN {
/* 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
};
static int state_machine(SSL *s, int server);
static void init_read_state_machine(SSL *s);
static enum SUB_STATE_RETURN read_state_machine(SSL *s);
static void init_write_state_machine(SSL *s);
static enum SUB_STATE_RETURN write_state_machine(SSL *s);
static inline int cert_req_allowed(SSL *s);
static inline int key_exchange_skip_allowed(SSL *s);
static int client_read_transition(SSL *s, int mt);
static enum WRITE_TRAN client_write_transition(SSL *s);
static enum WORK_STATE client_pre_work(SSL *s, enum WORK_STATE wst);
static enum WORK_STATE client_post_work(SSL *s, enum WORK_STATE wst);
static int client_construct_message(SSL *s);
static unsigned long client_max_message_size(SSL *s);
static enum MSG_PROCESS_RETURN client_process_message(SSL *s,
unsigned long len);
static enum WORK_STATE client_post_process_message(SSL *s, enum WORK_STATE wst);
static int server_read_transition(SSL *s, int mt);
static inline int send_server_key_exchange(SSL *s);
static inline int send_certificate_request(SSL *s);
static enum WRITE_TRAN server_write_transition(SSL *s);
static enum WORK_STATE server_pre_work(SSL *s, enum WORK_STATE wst);
static enum WORK_STATE server_post_work(SSL *s, enum WORK_STATE wst);
static int server_construct_message(SSL *s);
static unsigned long server_max_message_size(SSL *s);
static enum MSG_PROCESS_RETURN server_process_message(SSL *s, unsigned long len);
static enum WORK_STATE server_post_process_message(SSL *s, enum WORK_STATE wst);
enum HANDSHAKE_STATE SSL_state(const SSL *ssl)
{
return ssl->statem.hand_state;
}
void SSL_set_state(SSL *ssl, enum HANDSHAKE_STATE state)
{
/*
* This function seems like a really bad idea. Should we remove it
* completely?
*/
ssl->statem.hand_state = state;
}
int SSL_in_init(SSL *s)
{
return s->statem.in_init;
}
int SSL_is_init_finished(SSL *s)
{
return !(s->statem.in_init) && (s->statem.hand_state == TLS_ST_OK);
}
int SSL_in_before(SSL *s)
{
/*
* 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 (s->statem.hand_state == TLS_ST_BEFORE)
&& (s->statem.state == MSG_FLOW_UNINITED);
}
/*
* Clear the state machine state and reset back to MSG_FLOW_UNINITED
*/
void statem_clear(SSL *s)
{
s->statem.state = MSG_FLOW_UNINITED;
s->statem.hand_state = TLS_ST_BEFORE;
s->statem.in_init = 1;
}
/*
* Set the state machine up ready for a renegotiation handshake
*/
void statem_set_renegotiate(SSL *s)
{
s->statem.state = MSG_FLOW_RENEGOTIATE;
s->statem.in_init = 1;
}
/*
* Put the state machine into an error state. This is a permanent error for
* the current connection.
*/
void statem_set_error(SSL *s)
{
s->statem.state = MSG_FLOW_ERROR;
}
/*
* Discover whether the current connection is in the error state.
*
* Valid return values are:
* 1: Yes
* 0: No
*/
int statem_in_error(const SSL *s)
{
if (s->statem.state == MSG_FLOW_ERROR)
return 1;
return 0;
}
void statem_set_in_init(SSL *s, int init)
{
s->statem.in_init = init;
}
int ssl3_connect(SSL *s) {
return state_machine(s, 0);
}
int dtls1_connect(SSL *s)
{
return state_machine(s, 0);
}
int ssl3_accept(SSL *s)
{
return state_machine(s, 1);
}
int dtls1_accept(SSL *s)
{
return state_machine(s, 1);
}
/*
* The main message flow state machine. We start in the MSG_FLOW_UNINITED or
* MSG_FLOW_RENEGOTIATE state and finish in MSG_FLOW_FINISHED. Valid states and
* transitions are as follows:
*
* MSG_FLOW_UNINITED MSG_FLOW_RENEGOTIATE
* | |
* +-----------------------+
* 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 *s, int server) {
BUF_MEM *buf = NULL;
unsigned long Time = (unsigned long)time(NULL);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
STATEM *st = &s->statem;
int ret = -1;
int ssret;
if (st->state == MSG_FLOW_ERROR) {
/* Shouldn't have been called if we're already in the error state */
return -1;
}
RAND_add(&Time, sizeof(Time), 0);
ERR_clear_error();
clear_sys_error();
if (s->info_callback != NULL)
cb = s->info_callback;
else if (s->ctx->info_callback != NULL)
cb = s->ctx->info_callback;
s->in_handshake++;
if (!SSL_in_init(s) || SSL_in_before(s)) {
if (!SSL_clear(s))
return -1;
}
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s)) {
/*
* Notify SCTP BIO socket to enter handshake mode and prevent stream
* identifier other than 0. Will be ignored if no SCTP is used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
s->in_handshake, NULL);
}
#endif
#ifndef OPENSSL_NO_HEARTBEATS
/*
* If we're awaiting a HeartbeatResponse, pretend we already got and
* don't await it anymore, because Heartbeats don't make sense during
* handshakes anyway.
*/
if (s->tlsext_hb_pending) {
if (SSL_IS_DTLS(s))
dtls1_stop_timer(s);
s->tlsext_hb_pending = 0;
s->tlsext_hb_seq++;
}
#endif
/* Initialise state machine */
if (st->state == MSG_FLOW_RENEGOTIATE) {
s->renegotiate = 1;
if (!server)
s->ctx->stats.sess_connect_renegotiate++;
}
if (st->state == MSG_FLOW_UNINITED || st->state == MSG_FLOW_RENEGOTIATE) {
if (st->state == MSG_FLOW_UNINITED) {
st->hand_state = TLS_ST_BEFORE;
}
s->server = server;
if (cb != NULL)
cb(s, SSL_CB_HANDSHAKE_START, 1);
if (SSL_IS_DTLS(s)) {
if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) &&
(server
|| (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
goto end;
}
} else {
if ((s->version >> 8) != SSL3_VERSION_MAJOR
&& s->version != TLS_ANY_VERSION) {
SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR);
goto end;
}
}
if (!SSL_IS_DTLS(s)) {
if (s->version != TLS_ANY_VERSION &&
!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
SSLerr(SSL_F_STATE_MACHINE, SSL_R_VERSION_TOO_LOW);
goto end;
}
}
if (server)
s->type = SSL_ST_ACCEPT;
else
s->type = SSL_ST_CONNECT;
if (s->init_buf == NULL) {
if ((buf = BUF_MEM_new()) == NULL) {
goto end;
}
if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
goto end;
}
s->init_buf = buf;
buf = NULL;
}
if (!ssl3_setup_buffers(s)) {
goto end;
}
s->init_num = 0;
/*
* Should have been reset by tls_process_finished, too.
*/
s->s3->change_cipher_spec = 0;
if (!server || st->state != MSG_FLOW_RENEGOTIATE) {
/*
* Ok, we now need to push on a buffering BIO ...but not with
* SCTP
*/
#ifndef OPENSSL_NO_SCTP
if (!SSL_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(s)))
#endif
if (!ssl_init_wbio_buffer(s, server ? 1 : 0)) {
goto end;
}
ssl3_init_finished_mac(s);
}
if (server) {
if (st->state != MSG_FLOW_RENEGOTIATE) {
s->ctx->stats.sess_accept++;
} else if (!s->s3->send_connection_binding &&
!(s->options &
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
/*
* Server attempting to renegotiate with client that doesn't
* support secure renegotiation.
*/
SSLerr(SSL_F_STATE_MACHINE,
SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
statem_set_error(s);
goto end;
} else {
/*
* s->state == SSL_ST_RENEGOTIATE, we will just send a
* HelloRequest
*/
s->ctx->stats.sess_accept_renegotiate++;
}
} else {
s->ctx->stats.sess_connect++;
/* mark client_random uninitialized */
memset(s->s3->client_random, 0, sizeof(s->s3->client_random));
s->hit = 0;
s->s3->tmp.cert_request = 0;
if (SSL_IS_DTLS(s)) {
st->use_timer = 1;
}
}
st->state = MSG_FLOW_WRITING;
init_write_state_machine(s);
st->read_state_first_init = 1;
}
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 */
statem_set_error(s);
goto end;
}
}
st->state = MSG_FLOW_UNINITED;
ret = 1;
end:
s->in_handshake--;
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s)) {
/*
* Notify SCTP BIO socket to leave handshake mode and allow stream
* identifier other than 0. Will be ignored if no SCTP is used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
s->in_handshake, NULL);
}
#endif
BUF_MEM_free(buf);
if (cb != NULL) {
if (server)
cb(s, SSL_CB_ACCEPT_EXIT, ret);
else
cb(s, SSL_CB_CONNECT_EXIT, ret);
}
return ret;
}
/*
* Initialise the MSG_FLOW_READING sub-state machine
*/
static void init_read_state_machine(SSL *s)
{
STATEM *st = &s->statem;
st->read_state = READ_STATE_HEADER;
}
/*
* 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 occuring 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 enum SUB_STATE_RETURN read_state_machine(SSL *s) {
STATEM *st = &s->statem;
int ret, mt;
unsigned long len;
int (*transition)(SSL *s, int mt);
enum MSG_PROCESS_RETURN (*process_message)(SSL *s, unsigned long n);
enum WORK_STATE (*post_process_message)(SSL *s, enum WORK_STATE wst);
unsigned long (*max_message_size)(SSL *s);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
if (s->info_callback != NULL)
cb = s->info_callback;
else if (s->ctx->info_callback != NULL)
cb = s->ctx->info_callback;
if(s->server) {
transition = server_read_transition;
process_message = server_process_message;
max_message_size = server_max_message_size;
post_process_message = server_post_process_message;
} else {
transition = client_read_transition;
process_message = client_process_message;
max_message_size = client_max_message_size;
post_process_message = 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:
s->init_num = 0;
/* 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)) {
ssl3_send_alert(s, SSL3_AL_FATAL, SSL3_AD_UNEXPECTED_MESSAGE);
SSLerr(SSL_F_READ_STATE_MACHINE, SSL_R_UNEXPECTED_MESSAGE);
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;
}
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;
ret = process_message(s, len);
if (ret == MSG_PROCESS_ERROR) {
return SUB_STATE_ERROR;
}
if (ret == MSG_PROCESS_FINISHED_READING) {
if (SSL_IS_DTLS(s)) {
dtls1_stop_timer(s);
}
return SUB_STATE_FINISHED;
}
if (ret == MSG_PROCESS_CONTINUE_PROCESSING) {
st->read_state = READ_STATE_POST_PROCESS;
st->read_state_work = WORK_MORE_A;
} else {
st->read_state = READ_STATE_HEADER;
}
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);
statem_set_error(s);
return SUB_STATE_ERROR;
}
}
}
/*
* Send a previously constructed message to the peer.
*/
static int statem_do_write(SSL *s)
{
STATEM *st = &s->statem;
if (st->hand_state == TLS_ST_CW_CHANGE
|| st->hand_state == TLS_ST_SW_CHANGE) {
if (SSL_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 *s)
{
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 occuring 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 enum SUB_STATE_RETURN write_state_machine(SSL *s)
{
STATEM *st = &s->statem;
int ret;
enum WRITE_TRAN (*transition)(SSL *s);
enum WORK_STATE (*pre_work)(SSL *s, enum WORK_STATE wst);
enum WORK_STATE (*post_work)(SSL *s, enum WORK_STATE wst);
int (*construct_message)(SSL *s);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
if (s->info_callback != NULL)
cb = s->info_callback;
else if (s->ctx->info_callback != NULL)
cb = s->ctx->info_callback;
if(s->server) {
transition = server_write_transition;
pre_work = server_pre_work;
post_work = server_post_work;
construct_message = server_construct_message;
} else {
transition = client_write_transition;
pre_work = client_pre_work;
post_work = client_post_work;
construct_message = 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(s, SSL_CB_ACCEPT_LOOP, 1);
else
cb(s, 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;
default:
return SUB_STATE_ERROR;
}
break;
case WRITE_STATE_PRE_WORK:
switch(st->write_state_work = pre_work(s, st->write_state_work)) {
default:
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(construct_message(s) == 0)
return SUB_STATE_ERROR;
/* Fall through */
case WRITE_STATE_SEND:
if (SSL_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)) {
default:
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:
return SUB_STATE_ERROR;
}
}
}
/*
* Flush the write BIO
*/
static int statem_flush(SSL *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 sent in the current handshake state or not.
*
* Return values are:
* 1: Yes (application data allowed)
* 0: No (application data not allowed)
*/
int statem_app_data_allowed(SSL *s)
{
STATEM *st = &s->statem;
if (st->state == MSG_FLOW_UNINITED || st->state == MSG_FLOW_RENEGOTIATE)
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;
}
#ifndef OPENSSL_NO_SCTP
/*
* Set flag used by SCTP to determine whether we are in the read sock state
*/
void statem_set_sctp_read_sock(SSL *s, int read_sock)
{
s->statem.in_sctp_read_sock = read_sock;
}
/*
* Called by the record layer to determine whether we are in the read sock
* state or not.
*
* Return values are:
* 1: Yes (we are in the read sock state)
* 0: No (we are not in the read sock state)
*/
int statem_in_sctp_read_sock(SSL *s)
{
return s->statem.in_sctp_read_sock;
}
#endif
/*
* Is a CertificateRequest message allowed at the moment or not?
*
* Return values are:
* 1: Yes
* 0: No
*/
static inline int cert_req_allowed(SSL *s)
{
/* TLS does not like anon-DH with client cert */
if (s->version > SSL3_VERSION
&& (s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL))
return 0;
return 1;
}
/*
* Are we allowed to skip the ServerKeyExchange message?
*
* Return values are:
* 1: Yes
* 0: No
*/
static inline int key_exchange_skip_allowed(SSL *s)
{
long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
/*
* Can't skip server key exchange if this is an ephemeral
* ciphersuite.
*/
if (alg_k & (SSL_kDHE | SSL_kECDHE)) {
return 0;
}
return 1;
}
/*
* 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)
*/
static int client_read_transition(SSL *s, int mt)
{
STATEM *st = &s->statem;
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->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 {
if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
st->hand_state = TLS_ST_CR_KEY_EXCH;
return 1;
} else if (key_exchange_skip_allowed(s)) {
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:
if (s->tlsext_status_expected) {
if (mt == SSL3_MT_CERTIFICATE_STATUS) {
st->hand_state = TLS_ST_CR_CERT_STATUS;
return 1;
}
} else {
if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
st->hand_state = TLS_ST_CR_KEY_EXCH;
return 1;
} else if (key_exchange_skip_allowed(s)) {
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_STATUS:
if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
st->hand_state = TLS_ST_CR_KEY_EXCH;
return 1;
} else if (key_exchange_skip_allowed(s)) {
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_KEY_EXCH:
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_REQ:
if (mt == SSL3_MT_SERVER_DONE) {
st->hand_state = TLS_ST_CR_SRVR_DONE;
return 1;
}
break;
case TLS_ST_CW_FINISHED:
if (mt == SSL3_MT_NEWSESSION_TICKET && s->tlsext_ticket_expected) {
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;
}
/* No valid transition found */
return 0;
}
/*
* client_write_transition() works out what handshake state to move to next
* when the client is writing messages to be sent to the server.
*/
static enum WRITE_TRAN client_write_transition(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_OK:
/* Renegotiation - fall through */
case TLS_ST_BEFORE:
st->hand_state = TLS_ST_CW_CLNT_HELLO;
return WRITE_TRAN_CONTINUE;
case TLS_ST_CW_CLNT_HELLO:
/*
* No transition at the end of writing because we don't know what
* we will be sent
*/
return WRITE_TRAN_FINISHED;
case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
st->hand_state = TLS_ST_CW_CLNT_HELLO;
return WRITE_TRAN_CONTINUE;
case TLS_ST_CR_SRVR_DONE:
if (s->s3->tmp.cert_req)
st->hand_state = TLS_ST_CW_CERT;
else
st->hand_state = TLS_ST_CW_KEY_EXCH;
return WRITE_TRAN_CONTINUE;
case TLS_ST_CW_CERT:
st->hand_state = TLS_ST_CW_KEY_EXCH;
return WRITE_TRAN_CONTINUE;
case TLS_ST_CW_KEY_EXCH:
/*
* For TLS, cert_req is set to 2, so a cert chain of nothing is
* sent, but no verify packet is sent
*/
/*
* XXX: For now, we do not support client authentication in ECDH
* cipher suites with ECDH (rather than ECDSA) certificates. We
* need to skip the certificate verify message when client's
* ECDH public key is sent inside the client certificate.
*/
if (s->s3->tmp.cert_req == 1) {
st->hand_state = TLS_ST_CW_CERT_VRFY;
} else {
st->hand_state = TLS_ST_CW_CHANGE;
}
if (s->s3->flags & TLS1_FLAGS_SKIP_CERT_VERIFY) {
st->hand_state = TLS_ST_CW_CHANGE;
}
return WRITE_TRAN_CONTINUE;
case TLS_ST_CW_CERT_VRFY:
st->hand_state = TLS_ST_CW_CHANGE;
return WRITE_TRAN_CONTINUE;
case TLS_ST_CW_CHANGE:
#if defined(OPENSSL_NO_NEXTPROTONEG)
st->hand_state = TLS_ST_CW_FINISHED;
#else
if (!SSL_IS_DTLS(s) && s->s3->next_proto_neg_seen)
st->hand_state = TLS_ST_CW_NEXT_PROTO;
else
st->hand_state = TLS_ST_CW_FINISHED;
#endif
return WRITE_TRAN_CONTINUE;
#if !defined(OPENSSL_NO_NEXTPROTONEG)
case TLS_ST_CW_NEXT_PROTO:
st->hand_state = TLS_ST_CW_FINISHED;
return WRITE_TRAN_CONTINUE;
#endif
case TLS_ST_CW_FINISHED:
if (s->hit) {
st->hand_state = TLS_ST_OK;
statem_set_in_init(s, 0);
return WRITE_TRAN_CONTINUE;
} else {
return WRITE_TRAN_FINISHED;
}
case TLS_ST_CR_FINISHED:
if (s->hit) {
st->hand_state = TLS_ST_CW_CHANGE;
return WRITE_TRAN_CONTINUE;
} else {
st->hand_state = TLS_ST_OK;
statem_set_in_init(s, 0);
return WRITE_TRAN_CONTINUE;
}
default:
/* Shouldn't happen */
return WRITE_TRAN_ERROR;
}
}
/*
* Perform any pre work that needs to be done prior to sending a message from
* the client to the server.
*/
static enum WORK_STATE client_pre_work(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_CW_CLNT_HELLO:
s->shutdown = 0;
if (SSL_IS_DTLS(s)) {
/* every DTLS ClientHello resets Finished MAC */
ssl3_init_finished_mac(s);
}
break;
case TLS_ST_CW_CERT:
return tls_prepare_client_certificate(s, wst);
case TLS_ST_CW_CHANGE:
if (SSL_IS_DTLS(s)) {
if (s->hit) {
/*
* We're into the last flight so we don't retransmit these
* messages unless we need to.
*/
st->use_timer = 0;
}
#ifndef OPENSSL_NO_SCTP
if (BIO_dgram_is_sctp(SSL_get_wbio(s)))
return dtls_wait_for_dry(s);
#endif
}
return WORK_FINISHED_CONTINUE;
case TLS_ST_OK:
return tls_finish_handshake(s, wst);
default:
/* No pre work to be done */
break;
}
return WORK_FINISHED_CONTINUE;
}
/*
* Perform any work that needs to be done after sending a message from the
* client to the server.
*/
static enum WORK_STATE client_post_work(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
s->init_num = 0;
switch(st->hand_state) {
case TLS_ST_CW_CLNT_HELLO:
if (SSL_IS_DTLS(s) && s->d1->cookie_len > 0 && statem_flush(s) != 1)
return WORK_MORE_A;
#ifndef OPENSSL_NO_SCTP
/* Disable buffering for SCTP */
if (!SSL_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(s))) {
#endif
/*
* turn on buffering for the next lot of output
*/
if (s->bbio != s->wbio)
s->wbio = BIO_push(s->bbio, s->wbio);
#ifndef OPENSSL_NO_SCTP
}
#endif
if (SSL_IS_DTLS(s)) {
/* Treat the next message as the first packet */
s->first_packet = 1;
}
break;
case TLS_ST_CW_KEY_EXCH:
if (tls_client_key_exchange_post_work(s) == 0)
return WORK_ERROR;
break;
case TLS_ST_CW_CHANGE:
s->session->cipher = s->s3->tmp.new_cipher;
#ifdef OPENSSL_NO_COMP
s->session->compress_meth = 0;
#else
if (s->s3->tmp.new_compression == NULL)
s->session->compress_meth = 0;
else
s->session->compress_meth = s->s3->tmp.new_compression->id;
#endif
if (!s->method->ssl3_enc->setup_key_block(s))
return WORK_ERROR;
if (!s->method->ssl3_enc->change_cipher_state(s,
SSL3_CHANGE_CIPHER_CLIENT_WRITE))
return WORK_ERROR;
if (SSL_IS_DTLS(s)) {
#ifndef OPENSSL_NO_SCTP
if (s->hit) {
/*
* Change to new shared key of SCTP-Auth, will be ignored if
* no SCTP used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
0, NULL);
}
#endif
dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
}
break;
case TLS_ST_CW_FINISHED:
#ifndef OPENSSL_NO_SCTP
if (wst == WORK_MORE_A && SSL_IS_DTLS(s) && s->hit == 0) {
/*
* Change to new shared key of SCTP-Auth, will be ignored if
* no SCTP used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
0, NULL);
}
#endif
if (statem_flush(s) != 1)
return WORK_MORE_B;
if (s->hit && tls_finish_handshake(s, WORK_MORE_A) != 1)
return WORK_ERROR;
break;
default:
/* No post work to be done */
break;
}
return WORK_FINISHED_CONTINUE;
}
/*
* Construct a message to be sent from the client to the server.
*
* Valid return values are:
* 1: Success
* 0: Error
*/
static int client_construct_message(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_CW_CLNT_HELLO:
return tls_construct_client_hello(s);
case TLS_ST_CW_CERT:
return tls_construct_client_certificate(s);
case TLS_ST_CW_KEY_EXCH:
return tls_construct_client_key_exchange(s);
case TLS_ST_CW_CERT_VRFY:
return tls_construct_client_verify(s);
case TLS_ST_CW_CHANGE:
if (SSL_IS_DTLS(s))
return dtls_construct_change_cipher_spec(s);
else
return tls_construct_change_cipher_spec(s);
#if !defined(OPENSSL_NO_NEXTPROTONEG)
case TLS_ST_CW_NEXT_PROTO:
return tls_construct_next_proto(s);
#endif
case TLS_ST_CW_FINISHED:
return tls_construct_finished(s,
s->method->
ssl3_enc->client_finished_label,
s->method->
ssl3_enc->client_finished_label_len);
default:
/* Shouldn't happen */
break;
}
return 0;
}
/* The spec allows for a longer length than this, but we limit it */
#define HELLO_VERIFY_REQUEST_MAX_LENGTH 258
#define SERVER_HELLO_MAX_LENGTH 20000
#define SERVER_KEY_EXCH_MAX_LENGTH 102400
#define SERVER_HELLO_DONE_MAX_LENGTH 0
#define CCS_MAX_LENGTH 1
/* Max should actually be 36 but we are generous */
#define FINISHED_MAX_LENGTH 64
/*
* Returns the maximum allowed length for the current message that we are
* reading. Excludes the message header.
*/
static unsigned long client_max_message_size(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_CR_SRVR_HELLO:
return SERVER_HELLO_MAX_LENGTH;
case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
return HELLO_VERIFY_REQUEST_MAX_LENGTH;
case TLS_ST_CR_CERT:
return s->max_cert_list;
case TLS_ST_CR_CERT_STATUS:
return SSL3_RT_MAX_PLAIN_LENGTH;
case TLS_ST_CR_KEY_EXCH:
return SERVER_KEY_EXCH_MAX_LENGTH;
case TLS_ST_CR_CERT_REQ:
return SSL3_RT_MAX_PLAIN_LENGTH;
case TLS_ST_CR_SRVR_DONE:
return SERVER_HELLO_DONE_MAX_LENGTH;
case TLS_ST_CR_CHANGE:
return CCS_MAX_LENGTH;
case TLS_ST_CR_SESSION_TICKET:
return SSL3_RT_MAX_PLAIN_LENGTH;
case TLS_ST_CR_FINISHED:
return FINISHED_MAX_LENGTH;
default:
/* Shouldn't happen */
break;
}
return 0;
}
/*
* Process a message that the client has been received from the server.
*/
static enum MSG_PROCESS_RETURN client_process_message(SSL *s, unsigned long len)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_CR_SRVR_HELLO:
return tls_process_server_hello(s, len);
case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
return dtls_process_hello_verify(s, len);
case TLS_ST_CR_CERT:
return tls_process_server_certificate(s, len);
case TLS_ST_CR_CERT_STATUS:
return tls_process_cert_status(s, len);
case TLS_ST_CR_KEY_EXCH:
return tls_process_key_exchange(s, len);
case TLS_ST_CR_CERT_REQ:
return tls_process_certificate_request(s, len);
case TLS_ST_CR_SRVR_DONE:
return tls_process_server_done(s, len);
case TLS_ST_CR_CHANGE:
return tls_process_change_cipher_spec(s, len);
case TLS_ST_CR_SESSION_TICKET:
return tls_process_new_session_ticket(s, len);
case TLS_ST_CR_FINISHED:
return tls_process_finished(s, len);
default:
/* Shouldn't happen */
break;
}
return MSG_PROCESS_ERROR;
}
/*
* Perform any further processing required following the receipt of a message
* from the server
*/
static enum WORK_STATE client_post_process_message(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
#ifndef OPENSSL_NO_SCTP
case TLS_ST_CR_SRVR_DONE:
/* We only get here if we are using SCTP and we are renegotiating */
if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
s->s3->in_read_app_data = 2;
s->rwstate = SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
statem_set_sctp_read_sock(s, 1);
return WORK_MORE_A;
}
statem_set_sctp_read_sock(s, 0);
return WORK_FINISHED_STOP;
#endif
case TLS_ST_CR_FINISHED:
if (!s->hit)
return tls_finish_handshake(s, wst);
else
return WORK_FINISHED_STOP;
default:
break;
}
/* Shouldn't happen */
return WORK_ERROR;
}
/*
* server_read_transition() encapsulates the logic for the allowed handshake
* state transitions when the server is reading messages from the client. The
* message type that the client has sent is provided in |mt|. The current state
* is in |s->statem.hand_state|.
*
* Valid return values are:
* 1: Success (transition allowed)
* 0: Error (transition not allowed)
*/
static int server_read_transition(SSL *s, int mt)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_BEFORE:
case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
if (mt == SSL3_MT_CLIENT_HELLO) {
st->hand_state = TLS_ST_SR_CLNT_HELLO;
return 1;
}
break;
case TLS_ST_SW_SRVR_DONE:
/*
* If we get a CKE message after a ServerDone then either
* 1) We didn't request a Certificate
* OR
* 2) If we did request one then
* a) We allow no Certificate to be returned
* AND
* b) We are running SSL3 (in TLS1.0+ the client must return a 0
* list if we requested a certificate)
*/
if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE
&& (!s->s3->tmp.cert_request
|| (!((s->verify_mode & SSL_VERIFY_PEER) &&
(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
&& (s->version == SSL3_VERSION)))) {
st->hand_state = TLS_ST_SR_KEY_EXCH;
return 1;
} else if (s->s3->tmp.cert_request) {
if (mt == SSL3_MT_CERTIFICATE) {
st->hand_state = TLS_ST_SR_CERT;
return 1;
}
}
break;
case TLS_ST_SR_CERT:
if (mt == SSL3_MT_CLIENT_KEY_EXCHANGE) {
st->hand_state = TLS_ST_SR_KEY_EXCH;
return 1;
}
break;
case TLS_ST_SR_KEY_EXCH:
/*
* We should only process a CertificateVerify message if we have
* received a Certificate from the client. If so then |s->session->peer|
* will be non NULL. In some instances a CertificateVerify message is
* not required even if the peer has sent a Certificate (e.g. such as in
* the case of static DH). In that case |s->no_cert_verify| should be
* set.
*/
if (s->session->peer == NULL || s->no_cert_verify) {
if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
/*
* For the ECDH ciphersuites when the client sends its ECDH
* pub key in a certificate, the CertificateVerify message is
* not sent. Also for GOST ciphersuites when the client uses
* its key from the certificate for key exchange.
*/
st->hand_state = TLS_ST_SR_CHANGE;
return 1;
}
} else {
if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
st->hand_state = TLS_ST_SR_CERT_VRFY;
return 1;
}
}
break;
case TLS_ST_SR_CERT_VRFY:
if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
st->hand_state = TLS_ST_SR_CHANGE;
return 1;
}
break;
case TLS_ST_SR_CHANGE:
#ifndef OPENSSL_NO_NEXTPROTONEG
if (s->s3->next_proto_neg_seen) {
if (mt == SSL3_MT_NEXT_PROTO) {
st->hand_state = TLS_ST_SR_NEXT_PROTO;
return 1;
}
} else {
#endif
if (mt == SSL3_MT_FINISHED) {
st->hand_state = TLS_ST_SR_FINISHED;
return 1;
}
#ifndef OPENSSL_NO_NEXTPROTONEG
}
#endif
break;
#ifndef OPENSSL_NO_NEXTPROTONEG
case TLS_ST_SR_NEXT_PROTO:
if (mt == SSL3_MT_FINISHED) {
st->hand_state = TLS_ST_SR_FINISHED;
return 1;
}
break;
#endif
case TLS_ST_SW_FINISHED:
if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
st->hand_state = TLS_ST_SR_CHANGE;
return 1;
}
break;
default:
break;
}
/* No valid transition found */
return 0;
}
/*
* Should we send a ServerKeyExchange message?
*
* Valid return values are:
* 1: Yes
* 0: No
*/
static inline int send_server_key_exchange(SSL *s)
{
unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
/*
* only send a ServerKeyExchange if DH, fortezza or RSA but we have a
* sign only certificate PSK: may send PSK identity hints For
* ECC ciphersuites, we send a serverKeyExchange message only if
* the cipher suite is either ECDH-anon or ECDHE. In other cases,
* the server certificate contains the server's public key for
* key exchange.
*/
if ( (alg_k & SSL_kDHE)
|| (alg_k & SSL_kECDHE)
|| ((alg_k & SSL_kRSA)
&& (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
|| (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
&& EVP_PKEY_size(s->cert->pkeys
[SSL_PKEY_RSA_ENC].privatekey) *
8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
)
)
)
/*
* PSK: send ServerKeyExchange if PSK identity hint if
* provided
*/
#ifndef OPENSSL_NO_PSK
/* Only send SKE if we have identity hint for plain PSK */
|| ((alg_k & (SSL_kPSK | SSL_kRSAPSK))
&& s->cert->psk_identity_hint)
/* For other PSK always send SKE */
|| (alg_k & (SSL_PSK & (SSL_kDHEPSK | SSL_kECDHEPSK)))
#endif
#ifndef OPENSSL_NO_SRP
/* SRP: send ServerKeyExchange */
|| (alg_k & SSL_kSRP)
#endif
) {
return 1;
}
return 0;
}
/*
* Should we send a CertificateRequest message?
*
* Valid return values are:
* 1: Yes
* 0: No
*/
static inline int send_certificate_request(SSL *s)
{
if (
/* don't request cert unless asked for it: */
s->verify_mode & SSL_VERIFY_PEER
/*
* if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
* during re-negotiation:
*/
&& ((s->session->peer == NULL) ||
!(s->verify_mode & SSL_VERIFY_CLIENT_ONCE))
/*
* never request cert in anonymous ciphersuites (see
* section "Certificate request" in SSL 3 drafts and in
* RFC 2246):
*/
&& (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
/*
* ... except when the application insists on
* verification (against the specs, but s3_clnt.c accepts
* this for SSL 3)
*/
|| (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
/* don't request certificate for SRP auth */
&& !(s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP)
/*
* With normal PSK Certificates and Certificate Requests
* are omitted
*/
&& !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) {
return 1;
}
return 0;
}
/*
* server_write_transition() works out what handshake state to move to next
* when the server is writing messages to be sent to the client.
*/
static enum WRITE_TRAN server_write_transition(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_BEFORE:
/* Just go straight to trying to read from the client */;
return WRITE_TRAN_FINISHED;
case TLS_ST_OK:
/* We must be trying to renegotiate */
st->hand_state = TLS_ST_SW_HELLO_REQ;
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_HELLO_REQ:
st->hand_state = TLS_ST_OK;
statem_set_in_init(s, 0);
return WRITE_TRAN_CONTINUE;
case TLS_ST_SR_CLNT_HELLO:
if (SSL_IS_DTLS(s) && !s->d1->cookie_verified
&& (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
st->hand_state = DTLS_ST_SW_HELLO_VERIFY_REQUEST;
else
st->hand_state = TLS_ST_SW_SRVR_HELLO;
return WRITE_TRAN_CONTINUE;
case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
return WRITE_TRAN_FINISHED;
case TLS_ST_SW_SRVR_HELLO:
if (s->hit) {
if (s->tlsext_ticket_expected)
st->hand_state = TLS_ST_SW_SESSION_TICKET;
else
st->hand_state = TLS_ST_SW_CHANGE;
} else {
/* Check if it is anon DH or anon ECDH, */
/* normal PSK or SRP */
if (!(s->s3->tmp.new_cipher->algorithm_auth &
(SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
st->hand_state = TLS_ST_SW_CERT;
} else if (send_server_key_exchange(s)) {
st->hand_state = TLS_ST_SW_KEY_EXCH;
} else if (send_certificate_request(s)) {
st->hand_state = TLS_ST_SW_CERT_REQ;
} else {
st->hand_state = TLS_ST_SW_SRVR_DONE;
}
}
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_CERT:
if (s->tlsext_status_expected) {
st->hand_state = TLS_ST_SW_CERT_STATUS;
return WRITE_TRAN_CONTINUE;
}
/* Fall through */
case TLS_ST_SW_CERT_STATUS:
if (send_server_key_exchange(s)) {
st->hand_state = TLS_ST_SW_KEY_EXCH;
return WRITE_TRAN_CONTINUE;
}
/* Fall through */
case TLS_ST_SW_KEY_EXCH:
if (send_certificate_request(s)) {
st->hand_state = TLS_ST_SW_CERT_REQ;
return WRITE_TRAN_CONTINUE;
}
/* Fall through */
case TLS_ST_SW_CERT_REQ:
st->hand_state = TLS_ST_SW_SRVR_DONE;
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_SRVR_DONE:
return WRITE_TRAN_FINISHED;
case TLS_ST_SR_FINISHED:
if (s->hit) {
st->hand_state = TLS_ST_OK;
statem_set_in_init(s, 0);
return WRITE_TRAN_CONTINUE;
} else if (s->tlsext_ticket_expected) {
st->hand_state = TLS_ST_SW_SESSION_TICKET;
} else {
st->hand_state = TLS_ST_SW_CHANGE;
}
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_SESSION_TICKET:
st->hand_state = TLS_ST_SW_CHANGE;
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_CHANGE:
st->hand_state = TLS_ST_SW_FINISHED;
return WRITE_TRAN_CONTINUE;
case TLS_ST_SW_FINISHED:
if (s->hit) {
return WRITE_TRAN_FINISHED;
}
st->hand_state = TLS_ST_OK;
statem_set_in_init(s, 0);
return WRITE_TRAN_CONTINUE;
default:
/* Shouldn't happen */
return WRITE_TRAN_ERROR;
}
}
/*
* Perform any pre work that needs to be done prior to sending a message from
* the server to the client.
*/
static enum WORK_STATE server_pre_work(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_SW_HELLO_REQ:
s->shutdown = 0;
if (SSL_IS_DTLS(s))
dtls1_clear_record_buffer(s);
break;
case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
s->shutdown = 0;
if (SSL_IS_DTLS(s)) {
dtls1_clear_record_buffer(s);
/* We don't buffer this message so don't use the timer */
st->use_timer = 0;
}
break;
case TLS_ST_SW_SRVR_HELLO:
if (SSL_IS_DTLS(s)) {
/*
* Messages we write from now on should be bufferred and
* retransmitted if necessary, so we need to use the timer now
*/
st->use_timer = 1;
}
break;
case TLS_ST_SW_SRVR_DONE:
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s)))
return dtls_wait_for_dry(s);
#endif
return WORK_FINISHED_CONTINUE;
case TLS_ST_SW_SESSION_TICKET:
if (SSL_IS_DTLS(s)) {
/*
* We're into the last flight. We don't retransmit the last flight
* unless we need to, so we don't use the timer
*/
st->use_timer = 0;
}
break;
case TLS_ST_SW_CHANGE:
s->session->cipher = s->s3->tmp.new_cipher;
if (!s->method->ssl3_enc->setup_key_block(s)) {
statem_set_error(s);
return WORK_ERROR;
}
if (SSL_IS_DTLS(s)) {
/*
* We're into the last flight. We don't retransmit the last flight
* unless we need to, so we don't use the timer. This might have
* already been set to 0 if we sent a NewSessionTicket message,
* but we'll set it again here in case we didn't.
*/
st->use_timer = 0;
}
return WORK_FINISHED_CONTINUE;
case TLS_ST_OK:
return tls_finish_handshake(s, wst);
default:
/* No pre work to be done */
break;
}
return WORK_FINISHED_CONTINUE;
}
/*
* Perform any work that needs to be done after sending a message from the
* server to the client.
*/
static enum WORK_STATE server_post_work(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
s->init_num = 0;
switch(st->hand_state) {
case TLS_ST_SW_HELLO_REQ:
if (statem_flush(s) != 1)
return WORK_MORE_A;
ssl3_init_finished_mac(s);
break;
case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
if (statem_flush(s) != 1)
return WORK_MORE_A;
/* HelloVerifyRequest resets Finished MAC */
if (s->version != DTLS1_BAD_VER)
ssl3_init_finished_mac(s);
/*
* The next message should be another ClientHello which we need to
* treat like it was the first packet
*/
s->first_packet = 1;
break;
case TLS_ST_SW_SRVR_HELLO:
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s) && s->hit) {
unsigned char sctpauthkey[64];
char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
/*
* Add new shared key for SCTP-Auth, will be ignored if no
* SCTP used.
*/
snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
DTLS1_SCTP_AUTH_LABEL);
if (SSL_export_keying_material(s, sctpauthkey,
sizeof(sctpauthkey), labelbuffer,
sizeof(labelbuffer), NULL, 0, 0) <= 0) {
statem_set_error(s);
return WORK_ERROR;
}
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
sizeof(sctpauthkey), sctpauthkey);
}
#endif
break;
case TLS_ST_SW_CHANGE:
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s) && !s->hit) {
/*
* Change to new shared key of SCTP-Auth, will be ignored if
* no SCTP used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
0, NULL);
}
#endif
if (!s->method->ssl3_enc->change_cipher_state(s,
SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
statem_set_error(s);
return WORK_ERROR;
}
if (SSL_IS_DTLS(s))
dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
break;
case TLS_ST_SW_SRVR_DONE:
if (statem_flush(s) != 1)
return WORK_MORE_A;
break;
case TLS_ST_SW_FINISHED:
if (statem_flush(s) != 1)
return WORK_MORE_A;
#ifndef OPENSSL_NO_SCTP
if (SSL_IS_DTLS(s) && s->hit) {
/*
* Change to new shared key of SCTP-Auth, will be ignored if
* no SCTP used.
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
0, NULL);
}
#endif
break;
default:
/* No post work to be done */
break;
}
return WORK_FINISHED_CONTINUE;
}
/*
* Construct a message to be sent from the server to the client.
*
* Valid return values are:
* 1: Success
* 0: Error
*/
static int server_construct_message(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
return dtls_construct_hello_verify_request(s);
case TLS_ST_SW_HELLO_REQ:
return tls_construct_hello_request(s);
case TLS_ST_SW_SRVR_HELLO:
return tls_construct_server_hello(s);
case TLS_ST_SW_CERT:
return tls_construct_server_certificate(s);
case TLS_ST_SW_KEY_EXCH:
return tls_construct_server_key_exchange(s);
case TLS_ST_SW_CERT_REQ:
return tls_construct_certificate_request(s);
case TLS_ST_SW_SRVR_DONE:
return tls_construct_server_done(s);
case TLS_ST_SW_SESSION_TICKET:
return tls_construct_new_session_ticket(s);
case TLS_ST_SW_CERT_STATUS:
return tls_construct_cert_status(s);
case TLS_ST_SW_CHANGE:
if (SSL_IS_DTLS(s))
return dtls_construct_change_cipher_spec(s);
else
return tls_construct_change_cipher_spec(s);
case TLS_ST_SW_FINISHED:
return tls_construct_finished(s,
s->method->
ssl3_enc->server_finished_label,
s->method->
ssl3_enc->server_finished_label_len);
default:
/* Shouldn't happen */
break;
}
return 0;
}
#define CLIENT_KEY_EXCH_MAX_LENGTH 2048
#define NEXT_PROTO_MAX_LENGTH 514
/*
* Returns the maximum allowed length for the current message that we are
* reading. Excludes the message header.
*/
static unsigned long server_max_message_size(SSL *s)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_SR_CLNT_HELLO:
return SSL3_RT_MAX_PLAIN_LENGTH;
case TLS_ST_SR_CERT:
return s->max_cert_list;
case TLS_ST_SR_KEY_EXCH:
return CLIENT_KEY_EXCH_MAX_LENGTH;
case TLS_ST_SR_CERT_VRFY:
return SSL3_RT_MAX_PLAIN_LENGTH;
#ifndef OPENSSL_NO_NEXTPROTONEG
case TLS_ST_SR_NEXT_PROTO:
return NEXT_PROTO_MAX_LENGTH;
#endif
case TLS_ST_SR_CHANGE:
return CCS_MAX_LENGTH;
case TLS_ST_SR_FINISHED:
return FINISHED_MAX_LENGTH;
default:
/* Shouldn't happen */
break;
}
return 0;
}
/*
* Process a message that the server has received from the client.
*/
static enum MSG_PROCESS_RETURN server_process_message(SSL *s,
unsigned long len)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_SR_CLNT_HELLO:
return tls_process_client_hello(s, len);
case TLS_ST_SR_CERT:
return tls_process_client_certificate(s, len);
case TLS_ST_SR_KEY_EXCH:
return tls_process_client_key_exchange(s, len);
case TLS_ST_SR_CERT_VRFY:
return tls_process_cert_verify(s, len);
#ifndef OPENSSL_NO_NEXTPROTONEG
case TLS_ST_SR_NEXT_PROTO:
return tls_process_next_proto(s, len);
#endif
case TLS_ST_SR_CHANGE:
return tls_process_change_cipher_spec(s, len);
case TLS_ST_SR_FINISHED:
return tls_process_finished(s, len);
default:
/* Shouldn't happen */
break;
}
return MSG_PROCESS_ERROR;
}
/*
* Perform any further processing required following the receipt of a message
* from the client
*/
static enum WORK_STATE server_post_process_message(SSL *s, enum WORK_STATE wst)
{
STATEM *st = &s->statem;
switch(st->hand_state) {
case TLS_ST_SR_CLNT_HELLO:
return tls_post_process_client_hello(s, wst);
case TLS_ST_SR_KEY_EXCH:
return tls_post_process_client_key_exchange(s, wst);
case TLS_ST_SR_CERT_VRFY:
#ifndef OPENSSL_NO_SCTP
if ( /* Is this SCTP? */
BIO_dgram_is_sctp(SSL_get_wbio(s))
/* Are we renegotiating? */
&& s->renegotiate
&& BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
s->s3->in_read_app_data = 2;
s->rwstate = SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
statem_set_sctp_read_sock(s, 1);
return WORK_MORE_A;
} else {
statem_set_sctp_read_sock(s, 0);
}
#endif
return WORK_FINISHED_CONTINUE;
case TLS_ST_SR_FINISHED:
if (s->hit)
return tls_finish_handshake(s, wst);
else
return WORK_FINISHED_STOP;
default:
break;
}
/* Shouldn't happen */
return WORK_ERROR;
}
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