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boringssl/ssl/d1_srvr.c
David Benjamin e4824e8af0 Add outgoing messages to the handshake hash at set_handshake_header. 
This avoids needing a should_add_to_finished_hash boolean on do_write. The
logic in do_write was a little awkward because do_write would be called
multiple times if the write took several iterations. This also gets complex if
DTLS retransmits are involved. (At a glance, it's not obvious the
BIO_CTRL_DGRAM_MTU_EXCEEDED case actually works.)

Doing it as the handshake message is being prepared avoids this concern. It
also gives a natural point for the extended master secret logic which needs to
do work after the finished hash has been sampled.

As a bonus, we can remove s->d1->retransmitting which was only used to deal
with this issue.

Change-Id: Ifedf23ee4a6c5e08f960d296a6eb1f337a16dc7a
Reviewed-on: https://boringssl-review.googlesource.com/2604
Reviewed-by: Adam Langley <agl@google.com>
2014-12-16 01:43:51 +00:00

633 lines
17 KiB
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/*
* DTLS implementation written by Nagendra Modadugu
* (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
*/
/* ====================================================================
* Copyright (c) 1999-2007 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).
*
*/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* 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 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 acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS 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 AUTHOR OR 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.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include <assert.h>
#include <stdio.h>
#include <openssl/bn.h>
#include <openssl/buf.h>
#include <openssl/dh.h>
#include <openssl/evp.h>
#include <openssl/md5.h>
#include <openssl/obj.h>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include "ssl_locl.h"
static int dtls1_send_hello_verify_request(SSL *s);
int dtls1_accept(SSL *s)
{
BUF_MEM *buf = NULL;
void (*cb)(const SSL *ssl,int type,int val)=NULL;
unsigned long alg_a;
int ret= -1;
int new_state,state,skip=0;
assert(s->handshake_func == dtls1_accept);
assert(s->server);
assert(SSL_IS_DTLS(s));
ERR_clear_error();
ERR_clear_system_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 (s->cert == NULL)
{
OPENSSL_PUT_ERROR(SSL, dtls1_accept, SSL_R_NO_CERTIFICATE_SET);
return(-1);
}
for (;;)
{
state=s->state;
switch (s->state)
{
case SSL_ST_RENEGOTIATE:
s->renegotiate=1;
/* s->state=SSL_ST_ACCEPT; */
case SSL_ST_ACCEPT:
case SSL_ST_BEFORE|SSL_ST_ACCEPT:
if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);
if (s->init_buf == NULL)
{
if ((buf=BUF_MEM_new()) == NULL)
{
ret= -1;
goto end;
}
if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
{
ret= -1;
goto end;
}
s->init_buf=buf;
buf = NULL;
}
if (!ssl3_setup_buffers(s))
{
ret= -1;
goto end;
}
s->init_num=0;
if (s->state != SSL_ST_RENEGOTIATE)
{
/* Ok, we now need to push on a buffering BIO so that
* the output is sent in a way that TCP likes :-)
* ...but not with SCTP :-)
*/
if (!ssl_init_wbio_buffer(s,1)) { ret= -1; goto end; }
if (!ssl3_init_finished_mac(s))
{
OPENSSL_PUT_ERROR(SSL, dtls1_accept, ERR_R_INTERNAL_ERROR);
ret = -1;
goto end;
}
s->state=SSL3_ST_SR_CLNT_HELLO_A;
s->ctx->stats.sess_accept++;
}
else
{
/* s->state == SSL_ST_RENEGOTIATE,
* we will just send a HelloRequest */
s->ctx->stats.sess_accept_renegotiate++;
s->state=SSL3_ST_SW_HELLO_REQ_A;
}
break;
case SSL3_ST_SW_HELLO_REQ_A:
case SSL3_ST_SW_HELLO_REQ_B:
s->shutdown=0;
dtls1_clear_record_buffer(s);
dtls1_start_timer(s);
ret=ssl3_send_hello_request(s);
if (ret <= 0) goto end;
s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
s->state=SSL3_ST_SW_FLUSH;
s->init_num=0;
if (!ssl3_init_finished_mac(s))
{
OPENSSL_PUT_ERROR(SSL, dtls1_accept, ERR_R_INTERNAL_ERROR);
ret = -1;
goto end;
}
break;
case SSL3_ST_SW_HELLO_REQ_C:
s->state=SSL_ST_OK;
break;
case SSL3_ST_SR_CLNT_HELLO_A:
case SSL3_ST_SR_CLNT_HELLO_B:
case SSL3_ST_SR_CLNT_HELLO_C:
case SSL3_ST_SR_CLNT_HELLO_D:
s->shutdown=0;
ret=ssl3_get_client_hello(s);
if (ret <= 0) goto end;
dtls1_stop_timer(s);
if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
else
s->state = SSL3_ST_SW_SRVR_HELLO_A;
s->init_num=0;
break;
case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:
ret = dtls1_send_hello_verify_request(s);
if ( ret <= 0) goto end;
s->state=SSL3_ST_SW_FLUSH;
s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
/* HelloVerifyRequest resets Finished MAC */
if (!ssl3_init_finished_mac(s))
{
OPENSSL_PUT_ERROR(SSL, dtls1_accept, ERR_R_INTERNAL_ERROR);
ret = -1;
goto end;
}
break;
case SSL3_ST_SW_SRVR_HELLO_A:
case SSL3_ST_SW_SRVR_HELLO_B:
s->renegotiate = 2;
dtls1_start_timer(s);
ret=ssl3_send_server_hello(s);
if (ret <= 0) goto end;
if (s->hit)
{
if (s->tlsext_ticket_expected)
s->state=SSL3_ST_SW_SESSION_TICKET_A;
else
s->state=SSL3_ST_SW_CHANGE_A;
}
else
s->state=SSL3_ST_SW_CERT_A;
s->init_num=0;
break;
case SSL3_ST_SW_CERT_A:
case SSL3_ST_SW_CERT_B:
/* Check if it is anon DH or normal PSK */
if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
&& !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK))
{
dtls1_start_timer(s);
ret=ssl3_send_server_certificate(s);
if (ret <= 0) goto end;
if (s->s3->tmp.certificate_status_expected)
s->state=SSL3_ST_SW_CERT_STATUS_A;
else
s->state=SSL3_ST_SW_KEY_EXCH_A;
}
else
{
skip = 1;
s->state=SSL3_ST_SW_KEY_EXCH_A;
}
s->init_num=0;
break;
case SSL3_ST_SW_KEY_EXCH_A:
case SSL3_ST_SW_KEY_EXCH_B:
alg_a = s->s3->tmp.new_cipher->algorithm_auth;
/* Send a ServerKeyExchange message if:
* - The key exchange is ephemeral or anonymous
* Diffie-Hellman.
* - There is a PSK identity hint.
*
* TODO(davidben): This logic is currently duplicated
* in s3_srvr.c. Fix this. In the meantime, keep them
* in sync.
*/
if (ssl_cipher_requires_server_key_exchange(s->s3->tmp.new_cipher) ||
((alg_a & SSL_aPSK) && s->psk_identity_hint))
{
dtls1_start_timer(s);
ret=ssl3_send_server_key_exchange(s);
if (ret <= 0) goto end;
}
else
skip=1;
s->state=SSL3_ST_SW_CERT_REQ_A;
s->init_num=0;
break;
case SSL3_ST_SW_CERT_REQ_A:
case SSL3_ST_SW_CERT_REQ_B:
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)) ||
/* With normal PSK Certificates and
* Certificate Requests are omitted */
(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK))
{
/* no cert request */
skip=1;
s->s3->tmp.cert_request=0;
s->state=SSL3_ST_SW_SRVR_DONE_A;
}
else
{
s->s3->tmp.cert_request=1;
dtls1_start_timer(s);
ret=ssl3_send_certificate_request(s);
if (ret <= 0) goto end;
#ifndef NETSCAPE_HANG_BUG
s->state=SSL3_ST_SW_SRVR_DONE_A;
#else
s->state=SSL3_ST_SW_FLUSH;
s->s3->tmp.next_state=SSL3_ST_SR_CERT_A;
#endif
s->init_num=0;
}
break;
case SSL3_ST_SW_SRVR_DONE_A:
case SSL3_ST_SW_SRVR_DONE_B:
dtls1_start_timer(s);
ret=ssl3_send_server_done(s);
if (ret <= 0) goto end;
s->s3->tmp.next_state=SSL3_ST_SR_CERT_A;
s->state=SSL3_ST_SW_FLUSH;
s->init_num=0;
break;
case SSL3_ST_SW_FLUSH:
s->rwstate=SSL_WRITING;
if (BIO_flush(s->wbio) <= 0)
{
/* If the write error was fatal, stop trying */
if (!BIO_should_retry(s->wbio))
{
s->rwstate=SSL_NOTHING;
s->state=s->s3->tmp.next_state;
}
ret= -1;
goto end;
}
s->rwstate=SSL_NOTHING;
s->state=s->s3->tmp.next_state;
break;
case SSL3_ST_SR_CERT_A:
case SSL3_ST_SR_CERT_B:
if (s->s3->tmp.cert_request)
{
ret=ssl3_get_client_certificate(s);
if (ret <= 0) goto end;
}
s->init_num=0;
s->state=SSL3_ST_SR_KEY_EXCH_A;
break;
case SSL3_ST_SR_KEY_EXCH_A:
case SSL3_ST_SR_KEY_EXCH_B:
ret=ssl3_get_client_key_exchange(s);
if (ret <= 0)
goto end;
s->state=SSL3_ST_SR_CERT_VRFY_A;
s->init_num=0;
break;
case SSL3_ST_SR_CERT_VRFY_A:
case SSL3_ST_SR_CERT_VRFY_B:
s->d1->change_cipher_spec_ok = 1;
/* we should decide if we expected this one */
ret=ssl3_get_cert_verify(s);
if (ret <= 0) goto end;
s->state=SSL3_ST_SR_FINISHED_A;
s->init_num=0;
break;
case SSL3_ST_SR_FINISHED_A:
case SSL3_ST_SR_FINISHED_B:
s->d1->change_cipher_spec_ok = 1;
ret=ssl3_get_finished(s,SSL3_ST_SR_FINISHED_A,
SSL3_ST_SR_FINISHED_B);
if (ret <= 0) goto end;
dtls1_stop_timer(s);
if (s->hit)
s->state=SSL_ST_OK;
else if (s->tlsext_ticket_expected)
s->state=SSL3_ST_SW_SESSION_TICKET_A;
else
s->state=SSL3_ST_SW_CHANGE_A;
s->init_num=0;
break;
case SSL3_ST_SW_SESSION_TICKET_A:
case SSL3_ST_SW_SESSION_TICKET_B:
ret=ssl3_send_new_session_ticket(s);
if (ret <= 0) goto end;
s->state=SSL3_ST_SW_CHANGE_A;
s->init_num=0;
break;
#if 0
// TODO(davidben): Implement OCSP stapling on the server.
case SSL3_ST_SW_CERT_STATUS_A:
case SSL3_ST_SW_CERT_STATUS_B:
ret=ssl3_send_cert_status(s);
if (ret <= 0) goto end;
s->state=SSL3_ST_SW_KEY_EXCH_A;
s->init_num=0;
break;
#endif
case SSL3_ST_SW_CHANGE_A:
case SSL3_ST_SW_CHANGE_B:
s->session->cipher=s->s3->tmp.new_cipher;
if (!s->enc_method->setup_key_block(s))
{ ret= -1; goto end; }
ret=dtls1_send_change_cipher_spec(s,
SSL3_ST_SW_CHANGE_A,SSL3_ST_SW_CHANGE_B);
if (ret <= 0) goto end;
s->state=SSL3_ST_SW_FINISHED_A;
s->init_num=0;
if (!s->enc_method->change_cipher_state(s,
SSL3_CHANGE_CIPHER_SERVER_WRITE))
{
ret= -1;
goto end;
}
dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
break;
case SSL3_ST_SW_FINISHED_A:
case SSL3_ST_SW_FINISHED_B:
ret=ssl3_send_finished(s,
SSL3_ST_SW_FINISHED_A,SSL3_ST_SW_FINISHED_B,
s->enc_method->server_finished_label,
s->enc_method->server_finished_label_len);
if (ret <= 0) goto end;
s->state=SSL3_ST_SW_FLUSH;
if (s->hit)
{
s->s3->tmp.next_state=SSL3_ST_SR_FINISHED_A;
}
else
{
s->s3->tmp.next_state=SSL_ST_OK;
}
s->init_num=0;
break;
case SSL_ST_OK:
/* clean a few things up */
ssl3_cleanup_key_block(s);
#if 0
BUF_MEM_free(s->init_buf);
s->init_buf=NULL;
#endif
/* remove buffering on output */
ssl_free_wbio_buffer(s);
s->init_num=0;
if (s->renegotiate == 2) /* skipped if we just sent a HelloRequest */
{
s->renegotiate=0;
s->new_session=0;
ssl_update_cache(s,SSL_SESS_CACHE_SERVER);
s->ctx->stats.sess_accept_good++;
/* s->server=1; */
if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_DONE,1);
}
ret = 1;
/* done handshaking, next message is client hello */
s->d1->handshake_read_seq = 0;
/* next message is server hello */
s->d1->handshake_write_seq = 0;
s->d1->next_handshake_write_seq = 0;
goto end;
/* break; */
default:
OPENSSL_PUT_ERROR(SSL, dtls1_accept, SSL_R_UNKNOWN_STATE);
ret= -1;
goto end;
/* break; */
}
if (!s->s3->tmp.reuse_message && !skip)
{
if ((cb != NULL) && (s->state != state))
{
new_state=s->state;
s->state=state;
cb(s,SSL_CB_ACCEPT_LOOP,1);
s->state=new_state;
}
}
skip=0;
}
end:
/* BIO_flush(s->wbio); */
s->in_handshake--;
if (buf != NULL)
BUF_MEM_free(buf);
if (cb != NULL)
cb(s,SSL_CB_ACCEPT_EXIT,ret);
return(ret);
}
int dtls1_send_hello_verify_request(SSL *s)
{
uint8_t *msg, *p;
if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A)
{
msg = p = ssl_handshake_start(s);
/* Always use DTLS 1.0 version: see RFC 6347 */
*(p++) = DTLS1_VERSION >> 8;
*(p++) = DTLS1_VERSION & 0xFF;
/* Inform the callback how much space is in the
* cookie's buffer. */
s->d1->cookie_len = sizeof(s->d1->cookie);
if (s->ctx->app_gen_cookie_cb == NULL ||
s->ctx->app_gen_cookie_cb(s, s->d1->cookie, &(s->d1->cookie_len)) == 0)
{
OPENSSL_PUT_ERROR(SSL, dtls1_send_hello_verify_request, ERR_R_INTERNAL_ERROR);
return 0;
}
*(p++) = (uint8_t) s->d1->cookie_len;
memcpy(p, s->d1->cookie, s->d1->cookie_len);
p += s->d1->cookie_len;
ssl_set_handshake_header(s, DTLS1_MT_HELLO_VERIFY_REQUEST,
p - msg);
s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
}
/* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
return ssl_do_write(s);
}
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