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openssl/ssl/statem.c
Matt Caswell 473483d42d Implement DTLS client move to new state machine 
Move all DTLS client side processing into the new state machine code. A
subsequent commit will clean up the old dead code.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
2015-10-30 08:32:44 +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);
/*
* Clear the state machine state and reset back to MSG_FLOW_UNINITED
*/
void statem_clear(SSL *s)
{
s->statem.state = MSG_FLOW_UNINITED;
}
/*
* Set the state machine up ready for a renegotiation handshake
*/
void statem_set_renegotiate(SSL *s)
{
s->statem.state = MSG_FLOW_RENEGOTIATE;
}
/*
* 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;
/* TODO: This is temporary - remove me */
s->state = SSL_ST_ERR;
}
int ssl3_connect(SSL *s) {
return state_machine(s, 0);
}
int dtls1_connect(SSL *s)
{
return state_machine(s, 0);
}
/*
* 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) {
/* TODO: Temporary - fix this */
if (server)
s->state = SSL_ST_ACCEPT;
else
s->state = SSL_ST_CONNECT;
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) {
/* TODO: Fill these in later when we've implemented them */
transition = NULL;
process_message = NULL;
post_process_message = NULL;
max_message_size = NULL;
} 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) {
/* TODO: Fill these in later when we've implemented them */
transition = NULL;
pre_work = NULL;
post_work = NULL;
construct_message = NULL;
} 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 (!s->s3->in_read_app_data || (s->s3->total_renegotiations == 0))
return 0;
if (!s->server) {
if (st->state == MSG_FLOW_UNINITED || st->state == MSG_FLOW_RENEGOTIATE)
return 0;
if(st->hand_state == TLS_ST_CW_CLNT_HELLO)
return 1;
return 0;
}
/*
* This is the old check for code still using the old state machine. This
* will be removed by a later commit
*/
if ((s->state & SSL_ST_ACCEPT) &&
(s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
(s->state >= SSL3_ST_SR_CLNT_HELLO_A)
)
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;
/* TODO: This needs removing */
s->state = SSL_ST_OK;
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;
/* TODO: This needs removing */
s->state = SSL_ST_OK;
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;
}
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