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Add initial state machine rewrite code

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This is the first drop of the new state machine code.

The rewrite has the following objectives:
- Remove duplication of state code between client and server
- Remove duplication of state code between TLS and DTLS
- Simplify transitions and bring the logic together in a single location
  so that it is easier to validate
- Remove duplication of code between each of the message handling functions
- Receive a message first and then work out whether that is a valid
  transition - not the other way around (the other way causes lots of issues
  where we are expecting one type of message next but actually get something
  else)
- Separate message flow state from handshake state (in order to better
  understand each)
  - message flow state = when to flush buffers; handling restarts in the
    event of NBIO events; handling the common flow of steps for reading a
    message and the common flow of steps for writing a message etc
  - handshake state = what handshake message are we working on now
- Control complexity: only the state machine can change state: keep all
  the state changes local to a file

This builds on previous state machine related work:
- Surface CCS processing in the state machine
- Version negotiation rewrite

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
This commit is contained in:
Matt Caswell 2015-07-29 14:23:56 +01:00
parent 9ab930b27d
commit f8e0a55738
8 changed files with 893 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/openssl/ssl.h
View File

@ -1928,6 +1928,7 @@ void ERR_load_SSL_strings(void);
# define SSL_F_DTLS1_SEND_SERVER_HELLO 266
# define SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE 267
# define SSL_F_DTLS1_WRITE_APP_DATA_BYTES 268
# define SSL_F_READ_STATE_MACHINE 352
# define SSL_F_SSL3_ACCEPT 128
# define SSL_F_SSL3_ADD_CERT_TO_BUF 296
# define SSL_F_SSL3_CALLBACK_CTRL 233
@ -2085,6 +2086,7 @@ void ERR_load_SSL_strings(void);
# define SSL_F_SSL_USE_RSAPRIVATEKEY_FILE 206
# define SSL_F_SSL_VERIFY_CERT_CHAIN 207
# define SSL_F_SSL_WRITE 208
# define SSL_F_STATE_MACHINE 353
# define SSL_F_TLS12_CHECK_PEER_SIGALG 333
# define SSL_F_TLS1_CERT_VERIFY_MAC 286
# define SSL_F_TLS1_CHANGE_CIPHER_STATE 209

26
ssl/Makefile
View File

@ -26,7 +26,8 @@ LIBSRC= \
ssl_ciph.c ssl_stat.c ssl_rsa.c \
ssl_asn1.c ssl_txt.c ssl_algs.c ssl_conf.c \
bio_ssl.c ssl_err.c t1_reneg.c tls_srp.c t1_trce.c ssl_utst.c \
record/ssl3_buffer.c record/ssl3_record.c record/dtls1_bitmap.c
record/ssl3_buffer.c record/ssl3_record.c record/dtls1_bitmap.c \
statem.c
LIBOBJ= \
s3_srvr.o s3_clnt.o s3_lib.o s3_enc.o record/rec_layer_s3.o \
s3_both.o s3_cbc.o s3_msg.o \
@ -37,7 +38,8 @@ LIBOBJ= \
ssl_ciph.o ssl_stat.o ssl_rsa.o \
ssl_asn1.o ssl_txt.o ssl_algs.o ssl_conf.o \
bio_ssl.o ssl_err.o t1_reneg.o tls_srp.o t1_trce.o ssl_utst.o \
record/ssl3_buffer.o record/ssl3_record.o record/dtls1_bitmap.o
record/ssl3_buffer.o record/ssl3_record.o record/dtls1_bitmap.o \
statem.o
SRC= $(LIBSRC)
@ -781,6 +783,26 @@ ssl_utst.o: ../include/openssl/stack.h ../include/openssl/symhacks.h
ssl_utst.o: ../include/openssl/tls1.h ../include/openssl/x509.h
ssl_utst.o: ../include/openssl/x509_vfy.h packet_locl.h record/record.h
ssl_utst.o: ssl_locl.h ssl_utst.c
statem.o: ../e_os.h ../include/openssl/asn1.h ../include/openssl/bio.h
statem.o: ../include/openssl/bn.h ../include/openssl/buffer.h
statem.o: ../include/openssl/comp.h ../include/openssl/crypto.h
statem.o: ../include/openssl/dsa.h ../include/openssl/dtls1.h
statem.o: ../include/openssl/e_os2.h ../include/openssl/ec.h
statem.o: ../include/openssl/ecdh.h ../include/openssl/ecdsa.h
statem.o: ../include/openssl/err.h ../include/openssl/evp.h
statem.o: ../include/openssl/hmac.h ../include/openssl/lhash.h
statem.o: ../include/openssl/obj_mac.h ../include/openssl/objects.h
statem.o: ../include/openssl/opensslconf.h ../include/openssl/opensslv.h
statem.o: ../include/openssl/ossl_typ.h ../include/openssl/pem.h
statem.o: ../include/openssl/pem2.h ../include/openssl/pkcs7.h
statem.o: ../include/openssl/pqueue.h ../include/openssl/rand.h
statem.o: ../include/openssl/rsa.h ../include/openssl/safestack.h
statem.o: ../include/openssl/sha.h ../include/openssl/srtp.h
statem.o: ../include/openssl/ssl.h ../include/openssl/ssl2.h
statem.o: ../include/openssl/ssl3.h ../include/openssl/stack.h
statem.o: ../include/openssl/symhacks.h ../include/openssl/tls1.h
statem.o: ../include/openssl/x509.h ../include/openssl/x509_vfy.h packet_locl.h
statem.o: record/record.h ssl_locl.h statem.c
t1_clnt.o: ../e_os.h ../include/openssl/asn1.h ../include/openssl/bio.h
t1_clnt.o: ../include/openssl/bn.h ../include/openssl/buffer.h
t1_clnt.o: ../include/openssl/comp.h ../include/openssl/crypto.h

1
ssl/s3_both.c
View File

@ -478,6 +478,7 @@ long ssl3_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
return n;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
statem_set_error(s);
*ok = 0;
return 0;
}

1
ssl/s3_lib.c
View File

@ -5132,6 +5132,7 @@ int ssl3_renegotiate_check(SSL *s)
*/
/* SSL_ST_ACCEPT */
s->state = SSL_ST_RENEGOTIATE;
statem_set_renegotiate(s);
s->s3->renegotiate = 0;
s->s3->num_renegotiations++;
s->s3->total_renegotiations++;

2
ssl/ssl_err.c
View File

@ -112,6 +112,7 @@ static ERR_STRING_DATA SSL_str_functs[] = {
{ERR_FUNC(SSL_F_DTLS1_SEND_SERVER_KEY_EXCHANGE),
"dtls1_send_server_key_exchange"},
{ERR_FUNC(SSL_F_DTLS1_WRITE_APP_DATA_BYTES), "dtls1_write_app_data_bytes"},
{ERR_FUNC(SSL_F_READ_STATE_MACHINE), "READ_STATE_MACHINE"},
{ERR_FUNC(SSL_F_SSL3_ACCEPT), "ssl3_accept"},
{ERR_FUNC(SSL_F_SSL3_ADD_CERT_TO_BUF), "SSL3_ADD_CERT_TO_BUF"},
{ERR_FUNC(SSL_F_SSL3_CALLBACK_CTRL), "ssl3_callback_ctrl"},
@ -313,6 +314,7 @@ static ERR_STRING_DATA SSL_str_functs[] = {
{ERR_FUNC(SSL_F_SSL_USE_RSAPRIVATEKEY_FILE), "SSL_use_RSAPrivateKey_file"},
{ERR_FUNC(SSL_F_SSL_VERIFY_CERT_CHAIN), "ssl_verify_cert_chain"},
{ERR_FUNC(SSL_F_SSL_WRITE), "SSL_write"},
{ERR_FUNC(SSL_F_STATE_MACHINE), "STATE_MACHINE"},
{ERR_FUNC(SSL_F_TLS12_CHECK_PEER_SIGALG), "tls12_check_peer_sigalg"},
{ERR_FUNC(SSL_F_TLS1_CERT_VERIFY_MAC), "tls1_cert_verify_mac"},
{ERR_FUNC(SSL_F_TLS1_CHANGE_CIPHER_STATE), "tls1_change_cipher_state"},

1
ssl/ssl_lib.c
View File

@ -218,6 +218,7 @@ int SSL_clear(SSL *s)
s->type = 0;
s->state = SSL_ST_BEFORE | ((s->server) ? SSL_ST_ACCEPT : SSL_ST_CONNECT);
statem_clear(s);
s->version = s->method->version;
s->client_version = s->version;

137
ssl/ssl_locl.h
View File

@ -717,6 +717,137 @@ struct ssl_comp_st {
DECLARE_STACK_OF(SSL_COMP)
DECLARE_LHASH_OF(SSL_SESSION);
/*
* The valid handshake states (one for each type message sent and one for each
* type of message received). There are also two "special" states:
* TLS = TLS or DTLS state
* DTLS = DTLS specific state
* CR/SR = Client Read/Server Read
* CW/SW = Client Write/Server Write
*
* The "special" states are:
* TLS_ST_BEFORE = No handshake has been initiated yet
* TLS_ST_OK = A handshake has been successfully completed
*/
enum HANDSHAKE_STATE {
TLS_ST_BEFORE,
TLS_ST_OK,
DTLS_ST_CR_HELLO_VERIFY_REQUEST,
TLS_ST_CR_SRVR_HELLO,
TLS_ST_CR_CERT,
TLS_ST_CR_CERT_STATUS,
TLS_ST_CR_KEY_EXCH,
TLS_ST_CR_CERT_REQ,
TLS_ST_CR_SRVR_DONE,
TLS_ST_CR_SESSION_TICKET,
TLS_ST_CR_CHANGE,
TLS_ST_CR_FINISHED,
TLS_ST_CW_CLNT_HELLO,
TLS_ST_CW_CERT,
TLS_ST_CW_KEY_EXCH,
TLS_ST_CW_CERT_VRFY,
TLS_ST_CW_CHANGE,
TLS_ST_CW_NEXT_PROTO,
TLS_ST_CW_FINISHED,
TLS_ST_SW_HELLO_REQ,
TLS_ST_SR_CLNT_HELLO,
DTLS_ST_SW_HELLO_VERIFY_REQUEST,
TLS_ST_SW_SRVR_HELLO,
TLS_ST_SW_CERT,
TLS_ST_SW_KEY_EXCH,
TLS_ST_SW_CERT_REQ,
TLS_ST_SW_SRVR_DONE,
TLS_ST_SR_CERT,
TLS_ST_SR_KEY_EXCH,
TLS_ST_SR_CERT_VRFY,
TLS_ST_SR_NEXT_PROTO,
TLS_ST_SR_CHANGE,
TLS_ST_SR_FINISHED,
TLS_ST_SW_SESSION_TICKET,
TLS_ST_SW_CERT_STATUS,
TLS_ST_SW_CHANGE,
TLS_ST_SW_FINISHED
};
/*
* Valid return codes used for functions performing work prior to or after
* sending or receiving a message
*/
enum WORK_STATE {
/* Something went wrong */
WORK_ERROR,
/* We're done working and there shouldn't be anything else to do after */
WORK_FINISHED_STOP,
/* We're done working move onto the next thing */
WORK_FINISHED_CONTINUE,
/* We're working on phase A */
WORK_MORE_A,
/* We're working on phase B */
WORK_MORE_B
};
/* Write transition return codes */
enum WRITE_TRAN {
/* Something went wrong */
WRITE_TRAN_ERROR,
/* A transition was successfully completed and we should continue */
WRITE_TRAN_CONTINUE,
/* There is no more write work to be done */
WRITE_TRAN_FINISHED
};
/* Message processing return codes */
enum MSG_PROCESS_RETURN {
MSG_PROCESS_ERROR,
MSG_PROCESS_FINISHED_READING,
MSG_PROCESS_CONTINUE_PROCESSING,
MSG_PROCESS_CONTINUE_READING
};
/* Message flow states */
enum MSG_FLOW_STATE {
/* No handshake in progress */
MSG_FLOW_UNINITED,
/* A permanent error with this connection */
MSG_FLOW_ERROR,
/* We are about to renegotiate */
MSG_FLOW_RENEGOTIATE,
/* We are reading messages */
MSG_FLOW_READING,
/* We are writing messages */
MSG_FLOW_WRITING,
/* Handshake has finished */
MSG_FLOW_FINISHED
};
/* Read states */
enum READ_STATE {
READ_STATE_HEADER,
READ_STATE_BODY,
READ_STATE_POST_PROCESS
};
/* Write states */
enum WRITE_STATE {
WRITE_STATE_TRANSITION,
WRITE_STATE_PRE_WORK,
WRITE_STATE_SEND,
WRITE_STATE_POST_WORK
};
struct statem_st {
enum MSG_FLOW_STATE state;
enum WRITE_STATE write_state;
enum WORK_STATE write_state_work;
enum READ_STATE read_state;
enum WORK_STATE read_state_work;
enum HANDSHAKE_STATE hand_state;
int read_state_first_init;
int use_timer;
};
typedef struct statem_st STATEM;
struct ssl_ctx_st {
const SSL_METHOD *method;
STACK_OF(SSL_CIPHER) *cipher_list;
@ -1012,6 +1143,8 @@ struct ssl_st {
int shutdown;
/* where we are */
int state;
STATEM statem;
BUF_MEM *init_buf; /* buffer used during init */
void *init_msg; /* pointer to handshake message body, set by
* ssl3_get_message() */
@ -1951,6 +2084,10 @@ __owur int ssl3_new(SSL *s);
void ssl3_free(SSL *s);
__owur int ssl3_accept(SSL *s);
__owur int ssl3_connect(SSL *s);
void statem_clear(SSL *s);
void statem_set_renegotiate(SSL *s);
void statem_set_error(SSL *s);
__owur int statem_client_app_data_allowed(SSL *s);
__owur int ssl3_read(SSL *s, void *buf, int len);
__owur int ssl3_peek(SSL *s, void *buf, int len);
__owur int ssl3_write(SSL *s, const void *buf, int len);

725
ssl/statem.c Normal file
View File

@ -0,0 +1,725 @@
/* 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
};
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);
/*
* 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;
}
/*
* 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
*/
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_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 (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--;
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 {
/* TODO: Fill these in later when we've implemented them */
transition = NULL;
process_message = NULL;
post_process_message = NULL;
max_message_size = NULL;
}
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 */
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 {
/* TODO: Fill these in later when we've implemented them */
transition = NULL;
pre_work = NULL;
post_work = NULL;
construct_message = NULL;
}
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;
}
}
}
/*
* 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_client_app_data_allowed(SSL *s)
{
STATEM *st = &s->statem;
if(st->hand_state != TLS_ST_BEFORE &&
st->hand_state != TLS_ST_OK &&
st->hand_state != TLS_ST_CW_CLNT_HELLO)
return 0;
return 1;
}