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openssl/ssl/d1_srvr.c
Matt Caswell e3d0dae7cf DTLSv1_listen rewrite 
The existing implementation of DTLSv1_listen() is fundamentally flawed. This
function is used in DTLS solutions to listen for new incoming connections
from DTLS clients. A client will send an initial ClientHello. The server
will respond with a HelloVerifyRequest containing a unique cookie. The
client the responds with a second ClientHello - which this time contains the
cookie.

Once the cookie has been verified then DTLSv1_listen() returns to user code,
which is typically expected to continue the handshake with a call to (for
example) SSL_accept().

Whilst listening for incoming ClientHellos, the underlying BIO is usually in
an unconnected state. Therefore ClientHellos can come in from *any* peer.
The arrival of the first ClientHello without the cookie, and the second one
with it, could be interspersed with other intervening messages from
different clients.

The whole purpose of this mechanism is as a defence against DoS attacks. The
idea is to avoid allocating state on the server until the client has
verified that it is capable of receiving messages at the address it claims
to come from. However the existing DTLSv1_listen() implementation completely
fails to do this. It attempts to super-impose itself on the standard state
machine and reuses all of this code. However the standard state machine
expects to operate in a stateful manner with a single client, and this can
cause various problems.

A second more minor issue is that the return codes from this function are
quite confused, with no distinction made between fatal and non-fatal errors.
Most user code treats all errors as non-fatal, and simply retries the call
to DTLSv1_listen().

This commit completely rewrites the implementation of DTLSv1_listen() and
provides a stand alone implementation that does not rely on the existing
state machine. It also provides more consistent return codes.

Reviewed-by: Andy Polyakov <appro@openssl.org>
2015-09-23 13:53:26 +01:00

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/* ssl/d1_srvr.c */
/*
* 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 <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/md5.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_DH
# include <openssl/dh.h>
#endif
static const SSL_METHOD *dtls1_get_server_method(int ver);
static int dtls1_send_hello_verify_request(SSL *s);
static const SSL_METHOD *dtls1_get_server_method(int ver)
{
if (ver == DTLS1_VERSION)
return (DTLSv1_server_method());
else if (ver == DTLS1_2_VERSION)
return (DTLSv1_2_server_method());
else
return (NULL);
}
IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
DTLSv1_server_method,
dtls1_accept,
ssl_undefined_function,
dtls1_get_server_method, DTLSv1_enc_data)
IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
DTLSv1_2_server_method,
dtls1_accept,
ssl_undefined_function,
dtls1_get_server_method, DTLSv1_2_enc_data)
IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
DTLS_server_method,
dtls1_accept,
ssl_undefined_function,
dtls1_get_server_method, DTLSv1_2_enc_data)
int dtls1_accept(SSL *s)
{
BUF_MEM *buf;
unsigned long Time = (unsigned long)time(NULL);
void (*cb) (const SSL *ssl, int type, int val) = NULL;
unsigned long alg_k;
int ret = -1;
int new_state, state, skip = 0;
int listen;
#ifndef OPENSSL_NO_SCTP
unsigned char sctpauthkey[64];
char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
#endif
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;
listen = s->d1->listen;
/* init things to blank */
s->in_handshake++;
if (!SSL_in_init(s) || SSL_in_before(s)) {
if (!SSL_clear(s))
return -1;
}
s->d1->listen = listen;
#ifndef OPENSSL_NO_SCTP
/*
* 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) {
dtls1_stop_timer(s);
s->tlsext_hb_pending = 0;
s->tlsext_hb_seq++;
}
#endif
for (;;) {
state = s->state;
switch (s->state) {
case SSL_ST_RENEGOTIATE:
s->renegotiate = 1;
/* s->state=SSL_ST_ACCEPT; */
case SSL_ST_BEFORE:
case SSL_ST_ACCEPT:
case SSL_ST_BEFORE | SSL_ST_ACCEPT:
case SSL_ST_OK | SSL_ST_ACCEPT:
s->server = 1;
if (cb != NULL)
cb(s, SSL_CB_HANDSHAKE_START, 1);
if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
return -1;
}
s->type = SSL_ST_ACCEPT;
if (s->init_buf == NULL) {
if ((buf = BUF_MEM_new()) == NULL) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
BUF_MEM_free(buf);
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
s->init_buf = buf;
}
if (!ssl3_setup_buffers(s)) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
s->init_num = 0;
/*
* Should have been reset by ssl3_get_finished, too.
*/
s->s3->change_cipher_spec = 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 :-)
*/
#ifndef OPENSSL_NO_SCTP
if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
#endif
if (!ssl_init_wbio_buffer(s, 1)) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
ssl3_init_finished_mac(s);
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;
ssl3_init_finished_mac(s);
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:
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;
/*
* Reflect ClientHello sequence to remain stateless while
* listening
*/
if (listen) {
DTLS_RECORD_LAYER_resync_write(&s->rlayer);
}
/* If we're just listening, stop here */
if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
ret = 2;
s->d1->listen = 0;
/*
* Set expected sequence numbers to continue the handshake.
*/
s->d1->handshake_read_seq = 2;
s->d1->handshake_write_seq = 1;
s->d1->next_handshake_write_seq = 1;
goto end;
}
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 (s->version != DTLS1_BAD_VER)
ssl3_init_finished_mac(s);
break;
#ifndef OPENSSL_NO_SCTP
case DTLS1_SCTP_ST_SR_READ_SOCK:
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));
ret = -1;
goto end;
}
s->state = SSL3_ST_SR_CHANGE_A;
break;
case DTLS1_SCTP_ST_SW_WRITE_SOCK:
ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
if (ret < 0)
goto end;
if (ret == 0) {
if (s->d1->next_state != SSL_ST_OK) {
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));
ret = -1;
goto end;
}
}
s->state = s->d1->next_state;
break;
#endif
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) {
#ifndef OPENSSL_NO_SCTP
/*
* 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) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
sizeof(sctpauthkey), sctpauthkey);
#endif
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->tlsext_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_k = s->s3->tmp.new_cipher->algorithm_mkey;
/*
* clear this, it may get reset by
* send_server_key_exchange
*/
s->s3->tmp.use_rsa_tmp = 0;
/*
* only send if a DH key exchange or RSA but we have a sign only
* certificate
*/
if (0
/*
* PSK: send ServerKeyExchange if PSK identity hint if
* provided
*/
#ifndef OPENSSL_NO_PSK
|| ((alg_k & SSL_kPSK) && s->cert->psk_identity_hint)
#endif
|| (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)
)
)
)
) {
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;
#ifndef OPENSSL_NO_SCTP
if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
}
#endif
} else {
s->s3->tmp.cert_request = 1;
dtls1_start_timer(s);
ret = ssl3_send_certificate_request(s);
if (ret <= 0)
goto end;
s->state = SSL3_ST_SW_SRVR_DONE_A;
# ifndef OPENSSL_NO_SCTP
if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
}
# 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;
#ifndef OPENSSL_NO_SCTP
/*
* 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) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
sizeof(sctpauthkey), sctpauthkey);
#endif
s->state = SSL3_ST_SR_CERT_VRFY_A;
s->init_num = 0;
if (ret == 2) {
/*
* For the ECDH ciphersuites when the client sends its ECDH
* pub key in a certificate, the CertificateVerify message is
* not sent.
*/
s->state = SSL3_ST_SR_CHANGE_A;
s->init_num = 0;
} else if (SSL_USE_SIGALGS(s)) {
s->state = SSL3_ST_SR_CERT_VRFY_A;
s->init_num = 0;
if (!s->session->peer)
break;
if (!s->s3->handshake_buffer) {
SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
s->state = SSL_ST_ERR;
return -1;
}
/*
* For sigalgs freeze the handshake buffer. If we support
* extms we've done this already.
*/
if (!ssl3_digest_cached_records(s, 1)) {
s->state = SSL_ST_ERR;
return -1;
}
} else {
s->state = SSL3_ST_SR_CERT_VRFY_A;
s->init_num = 0;
/*
* We need to get hashes here so if there is a client cert,
* it can be verified
*/
s->method->ssl3_enc->cert_verify_mac(s,
NID_md5,
&(s->s3->
tmp.cert_verify_md
[0]));
s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
&(s->s3->
tmp.cert_verify_md
[MD5_DIGEST_LENGTH]));
}
break;
case SSL3_ST_SR_CERT_VRFY_A:
case SSL3_ST_SR_CERT_VRFY_B:
ret = ssl3_get_cert_verify(s);
if (ret <= 0)
goto end;
#ifndef OPENSSL_NO_SCTP
if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
state == SSL_ST_RENEGOTIATE)
s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
else
#endif
s->state = SSL3_ST_SR_CHANGE_A;
s->init_num = 0;
break;
case SSL3_ST_SR_CHANGE_A:
case SSL3_ST_SR_CHANGE_B:
ret = ssl3_get_change_cipher_spec(s, SSL3_ST_SR_CHANGE_A,
SSL3_ST_SR_CHANGE_B);
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:
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_newsession_ticket(s);
if (ret <= 0)
goto end;
s->state = SSL3_ST_SW_CHANGE_A;
s->init_num = 0;
break;
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;
case SSL3_ST_SW_CHANGE_A:
case SSL3_ST_SW_CHANGE_B:
s->session->cipher = s->s3->tmp.new_cipher;
if (!s->method->ssl3_enc->setup_key_block(s)) {
ret = -1;
s->state = SSL_ST_ERR;
goto end;
}
ret = dtls1_send_change_cipher_spec(s,
SSL3_ST_SW_CHANGE_A,
SSL3_ST_SW_CHANGE_B);
if (ret <= 0)
goto end;
#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
s->state = SSL3_ST_SW_FINISHED_A;
s->init_num = 0;
if (!s->method->ssl3_enc->change_cipher_state(s,
SSL3_CHANGE_CIPHER_SERVER_WRITE))
{
ret = -1;
s->state = SSL_ST_ERR;
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->method->
ssl3_enc->server_finished_label,
s->method->
ssl3_enc->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_CHANGE_A;
#ifndef OPENSSL_NO_SCTP
/*
* 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
} else {
s->s3->tmp.next_state = SSL_ST_OK;
#ifndef OPENSSL_NO_SCTP
if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
s->d1->next_state = s->s3->tmp.next_state;
s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
}
#endif
}
s->init_num = 0;
break;
case SSL_ST_OK:
/* clean a few things up */
ssl3_cleanup_key_block(s);
/* 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; */
s->handshake_func = dtls1_accept;
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; */
case SSL_ST_ERR:
default:
SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
ret = -1;
goto end;
/* break; */
}
if (!s->s3->tmp.reuse_message && !skip) {
if (s->debug) {
if ((ret = BIO_flush(s->wbio)) <= 0)
goto end;
}
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--;
#ifndef OPENSSL_NO_SCTP
/*
* Notify SCTP BIO socket to leave 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
if (cb != NULL)
cb(s, SSL_CB_ACCEPT_EXIT, ret);
return (ret);
}
unsigned int dtls1_raw_hello_verify_request(unsigned char *buf,
unsigned char *cookie,
unsigned char cookie_len)
{
unsigned int msg_len;
unsigned char *p;
p = buf;
/* Always use DTLS 1.0 version: see RFC 6347 */
*(p++) = DTLS1_VERSION >> 8;
*(p++) = DTLS1_VERSION & 0xFF;
*(p++) = (unsigned char)cookie_len;
memcpy(p, cookie, cookie_len);
p += cookie_len;
msg_len = p - buf;
return msg_len;
}
int dtls1_send_hello_verify_request(SSL *s)
{
unsigned int len;
unsigned char *buf;
if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
buf = (unsigned char *)s->init_buf->data;
if (s->ctx->app_gen_cookie_cb == NULL ||
s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
&(s->d1->cookie_len)) == 0) {
SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
ERR_R_INTERNAL_ERROR);
s->state = SSL_ST_ERR;
return 0;
}
len = dtls1_raw_hello_verify_request(&buf[DTLS1_HM_HEADER_LENGTH],
s->d1->cookie, s->d1->cookie_len);
dtls1_set_message_header(s, buf, DTLS1_MT_HELLO_VERIFY_REQUEST, len, 0,
len);
len += DTLS1_HM_HEADER_LENGTH;
s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
/* number of bytes to write */
s->init_num = len;
s->init_off = 0;
}
/* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}
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