ssl/s23_srvr.c - boringssl.git - Git at Google

 /* 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.]
  */
 /* ====================================================================
  * Copyright (c) 1998-2006 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 <assert.h>
 #include <stdio.h>

 #include <openssl/buf.h>
 #include <openssl/err.h>
 #include <openssl/evp.h>
 #include <openssl/mem.h>
 #include <openssl/obj.h>
 #include <openssl/rand.h>

 #include "ssl_locl.h"

 static const SSL_METHOD *ssl23_get_server_method(int ver);
 static int ssl23_get_client_hello(SSL *s);
 static int ssl23_get_v2_client_hello(SSL *s);

 static const SSL_METHOD *ssl23_get_server_method(int ver)
 	{
 	if (ver == SSL3_VERSION)
 		return(SSLv3_server_method());
 	else if (ver == TLS1_VERSION)
 		return(TLSv1_server_method());
 	else if (ver == TLS1_1_VERSION)
 		return(TLSv1_1_server_method());
 	else if (ver == TLS1_2_VERSION)
 		return(TLSv1_2_server_method());
 	else
 		return(NULL);
 	}

 IMPLEMENT_ssl23_meth_func(SSLv23_server_method,
 			ssl23_accept,
 			ssl_undefined_function,
 			ssl23_get_server_method)

 int ssl23_accept(SSL *s)
 	{
 	BUF_MEM *buf;
 	void (*cb)(const SSL *ssl,int type,int val)=NULL;
 	int ret= -1;
 	int new_state,state;

 	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 (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s);

 	for (;;)
 		{
 		state=s->state;

 		switch(s->state)
 			{
 		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);

 			/* s->version=SSL3_VERSION; */
 			s->type=SSL_ST_ACCEPT;

 			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;
 				}

 			ssl3_init_finished_mac(s);

 			s->state=SSL23_ST_SR_CLNT_HELLO;
 			s->ctx->stats.sess_accept++;
 			s->init_num=0;
 			break;

 		case SSL23_ST_SR_CLNT_HELLO:
 			s->shutdown = 0;
 			ret = ssl23_get_client_hello(s);
 			if (ret <= 0) goto end;
 			break;

 		case SSL23_ST_SR_V2_CLNT_HELLO:
 			ret = ssl23_get_v2_client_hello(s);
 			if (ret <= 0) goto end;
 			break;

 		case SSL23_ST_SR_SWITCH_VERSION:
 			if (!ssl_init_wbio_buffer(s, 1))
 				{
 				ret = -1;
 				goto end;
 				}

 			s->state = SSL3_ST_SR_CLNT_HELLO_A;
 			s->method = ssl23_get_server_method(s->version);
 			assert(s->method != NULL);
 			s->handshake_func = s->method->ssl_accept;
 			s->init_num = 0;

 			/* NULL the callback; SSL_accept will call it instead. */
 			cb = NULL;
 			ret = SSL_accept(s);
 			goto end;
 			/* break; */

 		default:
 			OPENSSL_PUT_ERROR(SSL, ssl23_accept, SSL_R_UNKNOWN_STATE);
 			ret= -1;
 			goto end;
 			/* break; */
 			}

 		if ((cb != NULL) && (s->state != state))
 			{
 			new_state=s->state;
 			s->state=state;
 			cb(s,SSL_CB_ACCEPT_LOOP,1);
 			s->state=new_state;
 			}
 		}
 end:
 	s->in_handshake--;
 	if (cb != NULL)
 		cb(s,SSL_CB_ACCEPT_EXIT,ret);
 	return(ret);
 	}

 /* ssl23_get_mutual_version determines the highest supported version for a
  * client which reports a highest version of |client_version|. On success, it
  * returns 1 and sets |*out_version| to the negotiated version. Otherwise, it
  * returns 0. */
 static int ssl23_get_mutual_version(SSL *s, int *out_version, uint16_t client_version)
 	{
 	if (client_version >= TLS1_2_VERSION && !(s->options & SSL_OP_NO_TLSv1_2))
 		{
 		*out_version = TLS1_2_VERSION;
 		return 1;
 		}
 	if (client_version >= TLS1_1_VERSION && !(s->options & SSL_OP_NO_TLSv1_1))
 		{
 		*out_version = TLS1_1_VERSION;
 		return 1;
 		}
 	if (client_version >= TLS1_VERSION && !(s->options & SSL_OP_NO_TLSv1))
 		{
 		*out_version = TLS1_VERSION;
 		return 1;
 		}
 	if (client_version >= SSL3_VERSION && !(s->options & SSL_OP_NO_SSLv3))
 		{
 		*out_version = SSL3_VERSION;
 		return 1;
 		}
 	return 0;
 	}

 static int ssl23_get_client_hello(SSL *s)
 	{
 	uint8_t *p;
 	int n = 0;

 	/* Sniff enough of the input to determine ClientHello type and the
 	 * client version. */
 	if (!ssl3_setup_buffers(s)) goto err;

 	/* Read the initial 11 bytes of the input. This is sufficient to
 	 * determine the client version for a ClientHello or a
 	 * V2ClientHello.
 	 *
 	 * ClientHello (assuming client_version is unfragmented):
 	 * Byte  Content
 	 *  0     type            \
 	 *  1-2   version          > record header
 	 *  3-4   length          /
 	 *  5     msg_type        \
 	 *  6-8   length           > Client Hello message
 	 *  9-10  client_version  /
 	 *
 	 * V2ClientHello:
 	 * Byte  Content
 	 *  0-1   msg_length
 	 *  2     msg_type
 	 *  3-4   version
 	 *  5-6   cipher_spec_length
 	 *  7-8   session_id_length
 	 *  9-10  challenge_length
 	 */
 	n = ssl23_read_bytes(s, 11);
 	if (n <= 0)
 		return n;
 	assert(n == 11);

 	p = s->packet;

 	/* Some dedicated error codes for protocol mixups should the application
 	 * wish to interpret them differently. (These do not overlap with
 	 * ClientHello or V2ClientHello.) */
 	if ((strncmp("GET ", (char *)p, 4) == 0) ||
 		(strncmp("POST ",(char *)p, 5) == 0) ||
 		(strncmp("HEAD ",(char *)p, 5) == 0) ||
 		(strncmp("PUT ", (char *)p, 4) == 0))
 		{
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_HTTP_REQUEST);
 		goto err;
 		}
 	if (strncmp("CONNECT",(char *)p, 7) == 0)
 		{
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_HTTPS_PROXY_REQUEST);
 		goto err;
 		}

 	/* Determine if this is a ClientHello or V2ClientHello. */
 	if ((p[0] & 0x80) && (p[2] == SSL2_MT_CLIENT_HELLO))
 		{
 		/* This is a V2ClientHello. Determine the version to
 		 * use. */
 		uint16_t client_version = (p[3] << 8) | p[4];
 		if (!ssl23_get_mutual_version(s, &s->version, client_version))
 			{
 			OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_UNSUPPORTED_PROTOCOL);
 			goto err;
 			}
 		/* Parse the entire V2ClientHello. */
 		s->state = SSL23_ST_SR_V2_CLNT_HELLO;
 		}
 	else if ((p[0] == SSL3_RT_HANDSHAKE) &&
 		 (p[1] >= SSL3_VERSION_MAJOR) &&
 		 (p[5] == SSL3_MT_CLIENT_HELLO))
 		{
 		/* This is a fragment of a ClientHello. We look at the
 		 * client_hello to negotiate the version. However, this
 		 * is difficult if we have only a pathologically small
 		 * fragment. No known client fragments ClientHello like
 		 * this, so we simply reject such connections to avoid
 		 * protocol version downgrade attacks. */
 		uint16_t record_length = (p[3] << 8) | p[4];
 		uint16_t client_version;
 		if (record_length < 6)
 			{
 			OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_RECORD_TOO_SMALL);
 			goto err;
 			}

 		client_version = (p[9] << 8) | p[10];
 		if (!ssl23_get_mutual_version(s, &s->version, client_version))
 			{
 			OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_UNSUPPORTED_PROTOCOL);
 			goto err;
 			}

                 /* Reset the record-layer state for SSL3. */
                 assert(s->rstate == SSL_ST_READ_HEADER);
                 s->s3->rbuf.left = s->packet_length;
                 s->s3->rbuf.offset = 0;
                 s->packet_length = 0;

 		/* Ready to switch versions. */
 		s->state = SSL23_ST_SR_SWITCH_VERSION;
 		}

 	return 1;
 err:
 	return -1;
 	}

 static int ssl23_get_v2_client_hello(SSL *s)
 	{
 	uint8_t *p;
 	size_t i;
 	int n = 0;

 	CBS v2_client_hello, cipher_specs, session_id, challenge;
 	size_t msg_length, len;
 	uint8_t msg_type;
 	uint16_t version, cipher_spec_length, session_id_length, challenge_length;
 	CBB client_hello, hello_body, cipher_suites;
 	uint8_t random[SSL3_RANDOM_SIZE];

 	/* Read the remainder of the V2ClientHello. We have previously read 11
 	 * bytes in ssl23_get_client_hello. */
 	p = s->packet;
 	msg_length = ((p[0] & 0x7f) << 8) | p[1];
 	if (msg_length > (1024 * 4))
 		{
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_RECORD_TOO_LARGE);
 		goto err;
 		}
 	if (msg_length < 11 - 2)
 		{
 		/* Reject lengths that are too short early. We have already read
 		 * 11 bytes, so we should not attempt to process an (invalid)
 		 * V2ClientHello which would be shorter than that. */
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_RECORD_LENGTH_MISMATCH);
 		goto err;
 		}
 	n = ssl23_read_bytes(s, msg_length + 2);
 	if (n <= 0)
 		return n;
 	assert(n == s->packet_length);

 	/* The V2ClientHello without the length is incorporated into the
 	 * Finished hash. */
 	ssl3_finish_mac(s, s->packet + 2, s->packet_length - 2);
 	if (s->msg_callback)
 		s->msg_callback(0, SSL2_VERSION, 0, s->packet+2, s->packet_length-2, s, s->msg_callback_arg); /* CLIENT-HELLO */

 	CBS_init(&v2_client_hello, s->packet + 2, s->packet_length - 2);
 	if (!CBS_get_u8(&v2_client_hello, &msg_type) ||
 		!CBS_get_u16(&v2_client_hello, &version) ||
 		!CBS_get_u16(&v2_client_hello, &cipher_spec_length) ||
 		!CBS_get_u16(&v2_client_hello, &session_id_length) ||
 		!CBS_get_u16(&v2_client_hello, &challenge_length) ||
 		!CBS_get_bytes(&v2_client_hello, &cipher_specs, cipher_spec_length) ||
 		!CBS_get_bytes(&v2_client_hello, &session_id, session_id_length) ||
 		!CBS_get_bytes(&v2_client_hello, &challenge, challenge_length) ||
 		CBS_len(&v2_client_hello) != 0)
 		{
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_DECODE_ERROR);
 		goto err;
 		}

 	/* msg_type has already been checked. */
 	assert(msg_type == SSL2_MT_CLIENT_HELLO);

 	/* The client_random is the V2ClientHello challenge. Truncate or
 	 * left-pad with zeros as needed. */
 	memset(random, 0, SSL3_RANDOM_SIZE);
 	i = (CBS_len(&challenge) > SSL3_RANDOM_SIZE) ? SSL3_RANDOM_SIZE : CBS_len(&challenge);
 	memcpy(random, CBS_data(&challenge), i);

 	/* Write out an equivalent SSLv3 ClientHello. */
 	if (!CBB_init_fixed(&client_hello, (uint8_t *)s->init_buf->data, s->init_buf->max))
 		{
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_MALLOC_FAILURE);
 		goto err;
 		}
 	if (!CBB_add_u8(&client_hello, SSL3_MT_CLIENT_HELLO) ||
 		!CBB_add_u24_length_prefixed(&client_hello, &hello_body) ||
 		!CBB_add_u16(&hello_body, version) ||
 		!CBB_add_bytes(&hello_body, random, SSL3_RANDOM_SIZE) ||
 		/* No session id. */
 		!CBB_add_u8(&hello_body, 0) ||
 		!CBB_add_u16_length_prefixed(&hello_body, &cipher_suites))
 		{
 		CBB_cleanup(&client_hello);
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
 		goto err;
 		}

 	/* Copy the cipher suites. */
 	while (CBS_len(&cipher_specs) > 0)
 		{
 		uint32_t cipher_spec;
 		if (!CBS_get_u24(&cipher_specs, &cipher_spec))
 			{
 			CBB_cleanup(&client_hello);
 			OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_DECODE_ERROR);
 			goto err;
 			}

 		/* Skip SSLv2 ciphers. */
 		if ((cipher_spec & 0xff0000) != 0)
 			continue;
 		if (!CBB_add_u16(&cipher_suites, cipher_spec))
 			{
 			CBB_cleanup(&client_hello);
 			OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
 			goto err;
 			}
 		}

 	/* Add the null compression scheme and finish. */
 	if (!CBB_add_u8(&hello_body, 1) ||
 		!CBB_add_u8(&hello_body, 0) ||
 		!CBB_finish(&client_hello, NULL, &len))
 		{
 		CBB_cleanup(&client_hello);
 		OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
 		goto err;
 		}

 	/* Mark the message for "re"-use by the version-specific
 	 * method. */
 	s->s3->tmp.reuse_message = 1;
 	s->s3->tmp.message_type = SSL3_MT_CLIENT_HELLO;
 	/* The handshake message header is 4 bytes. */
 	s->s3->tmp.message_size = len - 4;

 	/* Reset the record layer for SSL3. */
 	assert(s->rstate == SSL_ST_READ_HEADER);
 	s->packet_length = 0;
 	s->s3->rbuf.left = 0;
 	s->s3->rbuf.offset = 0;

 	s->state = SSL23_ST_SR_SWITCH_VERSION;
 	return 1;
 err:
 	return -1;
 	}
	/* 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.]
	*/
	/* ====================================================================
	* Copyright (c) 1998-2006 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 <assert.h>
	#include <stdio.h>

	#include <openssl/buf.h>
	#include <openssl/err.h>
	#include <openssl/evp.h>
	#include <openssl/mem.h>
	#include <openssl/obj.h>
	#include <openssl/rand.h>

	#include "ssl_locl.h"

	static const SSL_METHOD *ssl23_get_server_method(int ver);
	static int ssl23_get_client_hello(SSL *s);
	static int ssl23_get_v2_client_hello(SSL *s);

	static const SSL_METHOD *ssl23_get_server_method(int ver)
	{
	if (ver == SSL3_VERSION)
	return(SSLv3_server_method());
	else if (ver == TLS1_VERSION)
	return(TLSv1_server_method());
	else if (ver == TLS1_1_VERSION)
	return(TLSv1_1_server_method());
	else if (ver == TLS1_2_VERSION)
	return(TLSv1_2_server_method());
	else
	return(NULL);
	}

	IMPLEMENT_ssl23_meth_func(SSLv23_server_method,
	ssl23_accept,
	ssl_undefined_function,
	ssl23_get_server_method)

	int ssl23_accept(SSL *s)
	{
	BUF_MEM *buf;
	void (cb)(const SSL ssl,int type,int val)=NULL;
	int ret= -1;
	int new_state,state;

	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 (!SSL_in_init(s) \|\| SSL_in_before(s)) SSL_clear(s);

	for (;;)
	{
	state=s->state;

	switch(s->state)
	{
	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);

	/* s->version=SSL3_VERSION; */
	s->type=SSL_ST_ACCEPT;

	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;
	}

	ssl3_init_finished_mac(s);

	s->state=SSL23_ST_SR_CLNT_HELLO;
	s->ctx->stats.sess_accept++;
	s->init_num=0;
	break;

	case SSL23_ST_SR_CLNT_HELLO:
	s->shutdown = 0;
	ret = ssl23_get_client_hello(s);
	if (ret <= 0) goto end;
	break;

	case SSL23_ST_SR_V2_CLNT_HELLO:
	ret = ssl23_get_v2_client_hello(s);
	if (ret <= 0) goto end;
	break;

	case SSL23_ST_SR_SWITCH_VERSION:
	if (!ssl_init_wbio_buffer(s, 1))
	{
	ret = -1;
	goto end;
	}

	s->state = SSL3_ST_SR_CLNT_HELLO_A;
	s->method = ssl23_get_server_method(s->version);
	assert(s->method != NULL);
	s->handshake_func = s->method->ssl_accept;
	s->init_num = 0;

	/* NULL the callback; SSL_accept will call it instead. */
	cb = NULL;
	ret = SSL_accept(s);
	goto end;
	/* break; */

	default:
	OPENSSL_PUT_ERROR(SSL, ssl23_accept, SSL_R_UNKNOWN_STATE);
	ret= -1;
	goto end;
	/* break; */
	}

	if ((cb != NULL) && (s->state != state))
	{
	new_state=s->state;
	s->state=state;
	cb(s,SSL_CB_ACCEPT_LOOP,1);
	s->state=new_state;
	}
	}
	end:
	s->in_handshake--;
	if (cb != NULL)
	cb(s,SSL_CB_ACCEPT_EXIT,ret);
	return(ret);
	}

	/* ssl23_get_mutual_version determines the highest supported version for a
	* client which reports a highest version of \|client_version\|. On success, it
	* returns 1 and sets \|*out_version\| to the negotiated version. Otherwise, it
	* returns 0. */
	static int ssl23_get_mutual_version(SSL s, int out_version, uint16_t client_version)
	{
	if (client_version >= TLS1_2_VERSION && !(s->options & SSL_OP_NO_TLSv1_2))
	{
	*out_version = TLS1_2_VERSION;
	return 1;
	}
	if (client_version >= TLS1_1_VERSION && !(s->options & SSL_OP_NO_TLSv1_1))
	{
	*out_version = TLS1_1_VERSION;
	return 1;
	}
	if (client_version >= TLS1_VERSION && !(s->options & SSL_OP_NO_TLSv1))
	{
	*out_version = TLS1_VERSION;
	return 1;
	}
	if (client_version >= SSL3_VERSION && !(s->options & SSL_OP_NO_SSLv3))
	{
	*out_version = SSL3_VERSION;
	return 1;
	}
	return 0;
	}

	static int ssl23_get_client_hello(SSL *s)
	{
	uint8_t *p;
	int n = 0;

	/* Sniff enough of the input to determine ClientHello type and the
	* client version. */
	if (!ssl3_setup_buffers(s)) goto err;

	/* Read the initial 11 bytes of the input. This is sufficient to
	* determine the client version for a ClientHello or a
	* V2ClientHello.
	*
	* ClientHello (assuming client_version is unfragmented):
	* Byte Content
	* 0 type \
	* 1-2 version > record header
	* 3-4 length /
	* 5 msg_type \
	* 6-8 length > Client Hello message
	* 9-10 client_version /
	*
	* V2ClientHello:
	* Byte Content
	* 0-1 msg_length
	* 2 msg_type
	* 3-4 version
	* 5-6 cipher_spec_length
	* 7-8 session_id_length
	* 9-10 challenge_length
	*/
	n = ssl23_read_bytes(s, 11);
	if (n <= 0)
	return n;
	assert(n == 11);

	p = s->packet;

	/* Some dedicated error codes for protocol mixups should the application
	* wish to interpret them differently. (These do not overlap with
	* ClientHello or V2ClientHello.) */
	if ((strncmp("GET ", (char *)p, 4) == 0) \|\|
	(strncmp("POST ",(char *)p, 5) == 0) \|\|
	(strncmp("HEAD ",(char *)p, 5) == 0) \|\|
	(strncmp("PUT ", (char *)p, 4) == 0))
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_HTTP_REQUEST);
	goto err;
	}
	if (strncmp("CONNECT",(char *)p, 7) == 0)
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_HTTPS_PROXY_REQUEST);
	goto err;
	}

	/* Determine if this is a ClientHello or V2ClientHello. */
	if ((p[0] & 0x80) && (p[2] == SSL2_MT_CLIENT_HELLO))
	{
	/* This is a V2ClientHello. Determine the version to
	* use. */
	uint16_t client_version = (p[3] << 8) \| p[4];
	if (!ssl23_get_mutual_version(s, &s->version, client_version))
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_UNSUPPORTED_PROTOCOL);
	goto err;
	}
	/* Parse the entire V2ClientHello. */
	s->state = SSL23_ST_SR_V2_CLNT_HELLO;
	}
	else if ((p[0] == SSL3_RT_HANDSHAKE) &&
	(p[1] >= SSL3_VERSION_MAJOR) &&
	(p[5] == SSL3_MT_CLIENT_HELLO))
	{
	/* This is a fragment of a ClientHello. We look at the
	* client_hello to negotiate the version. However, this
	* is difficult if we have only a pathologically small
	* fragment. No known client fragments ClientHello like
	* this, so we simply reject such connections to avoid
	* protocol version downgrade attacks. */
	uint16_t record_length = (p[3] << 8) \| p[4];
	uint16_t client_version;
	if (record_length < 6)
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_RECORD_TOO_SMALL);
	goto err;
	}

	client_version = (p[9] << 8) \| p[10];
	if (!ssl23_get_mutual_version(s, &s->version, client_version))
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_client_hello, SSL_R_UNSUPPORTED_PROTOCOL);
	goto err;
	}

	/* Reset the record-layer state for SSL3. */
	assert(s->rstate == SSL_ST_READ_HEADER);
	s->s3->rbuf.left = s->packet_length;
	s->s3->rbuf.offset = 0;
	s->packet_length = 0;

	/* Ready to switch versions. */
	s->state = SSL23_ST_SR_SWITCH_VERSION;
	}

	return 1;
	err:
	return -1;
	}

	static int ssl23_get_v2_client_hello(SSL *s)
	{
	uint8_t *p;
	size_t i;
	int n = 0;

	CBS v2_client_hello, cipher_specs, session_id, challenge;
	size_t msg_length, len;
	uint8_t msg_type;
	uint16_t version, cipher_spec_length, session_id_length, challenge_length;
	CBB client_hello, hello_body, cipher_suites;
	uint8_t random[SSL3_RANDOM_SIZE];

	/* Read the remainder of the V2ClientHello. We have previously read 11
	* bytes in ssl23_get_client_hello. */
	p = s->packet;
	msg_length = ((p[0] & 0x7f) << 8) \| p[1];
	if (msg_length > (1024 * 4))
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_RECORD_TOO_LARGE);
	goto err;
	}
	if (msg_length < 11 - 2)
	{
	/* Reject lengths that are too short early. We have already read
	* 11 bytes, so we should not attempt to process an (invalid)
	* V2ClientHello which would be shorter than that. */
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_RECORD_LENGTH_MISMATCH);
	goto err;
	}
	n = ssl23_read_bytes(s, msg_length + 2);
	if (n <= 0)
	return n;
	assert(n == s->packet_length);

	/* The V2ClientHello without the length is incorporated into the
	* Finished hash. */
	ssl3_finish_mac(s, s->packet + 2, s->packet_length - 2);
	if (s->msg_callback)
	s->msg_callback(0, SSL2_VERSION, 0, s->packet+2, s->packet_length-2, s, s->msg_callback_arg); /* CLIENT-HELLO */

	CBS_init(&v2_client_hello, s->packet + 2, s->packet_length - 2);
	if (!CBS_get_u8(&v2_client_hello, &msg_type) \|\|
	!CBS_get_u16(&v2_client_hello, &version) \|\|
	!CBS_get_u16(&v2_client_hello, &cipher_spec_length) \|\|
	!CBS_get_u16(&v2_client_hello, &session_id_length) \|\|
	!CBS_get_u16(&v2_client_hello, &challenge_length) \|\|
	!CBS_get_bytes(&v2_client_hello, &cipher_specs, cipher_spec_length) \|\|
	!CBS_get_bytes(&v2_client_hello, &session_id, session_id_length) \|\|
	!CBS_get_bytes(&v2_client_hello, &challenge, challenge_length) \|\|
	CBS_len(&v2_client_hello) != 0)
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_DECODE_ERROR);
	goto err;
	}

	/* msg_type has already been checked. */
	assert(msg_type == SSL2_MT_CLIENT_HELLO);

	/* The client_random is the V2ClientHello challenge. Truncate or
	* left-pad with zeros as needed. */
	memset(random, 0, SSL3_RANDOM_SIZE);
	i = (CBS_len(&challenge) > SSL3_RANDOM_SIZE) ? SSL3_RANDOM_SIZE : CBS_len(&challenge);
	memcpy(random, CBS_data(&challenge), i);

	/* Write out an equivalent SSLv3 ClientHello. */
	if (!CBB_init_fixed(&client_hello, (uint8_t *)s->init_buf->data, s->init_buf->max))
	{
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_MALLOC_FAILURE);
	goto err;
	}
	if (!CBB_add_u8(&client_hello, SSL3_MT_CLIENT_HELLO) \|\|
	!CBB_add_u24_length_prefixed(&client_hello, &hello_body) \|\|
	!CBB_add_u16(&hello_body, version) \|\|
	!CBB_add_bytes(&hello_body, random, SSL3_RANDOM_SIZE) \|\|
	/* No session id. */
	!CBB_add_u8(&hello_body, 0) \|\|
	!CBB_add_u16_length_prefixed(&hello_body, &cipher_suites))
	{
	CBB_cleanup(&client_hello);
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
	goto err;
	}

	/* Copy the cipher suites. */
	while (CBS_len(&cipher_specs) > 0)
	{
	uint32_t cipher_spec;
	if (!CBS_get_u24(&cipher_specs, &cipher_spec))
	{
	CBB_cleanup(&client_hello);
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, SSL_R_DECODE_ERROR);
	goto err;
	}

	/* Skip SSLv2 ciphers. */
	if ((cipher_spec & 0xff0000) != 0)
	continue;
	if (!CBB_add_u16(&cipher_suites, cipher_spec))
	{
	CBB_cleanup(&client_hello);
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
	goto err;
	}
	}

	/* Add the null compression scheme and finish. */
	if (!CBB_add_u8(&hello_body, 1) \|\|
	!CBB_add_u8(&hello_body, 0) \|\|
	!CBB_finish(&client_hello, NULL, &len))
	{
	CBB_cleanup(&client_hello);
	OPENSSL_PUT_ERROR(SSL, ssl23_get_v2_client_hello, ERR_R_INTERNAL_ERROR);
	goto err;
	}

	/* Mark the message for "re"-use by the version-specific
	* method. */
	s->s3->tmp.reuse_message = 1;
	s->s3->tmp.message_type = SSL3_MT_CLIENT_HELLO;
	/* The handshake message header is 4 bytes. */
	s->s3->tmp.message_size = len - 4;

	/* Reset the record layer for SSL3. */
	assert(s->rstate == SSL_ST_READ_HEADER);
	s->packet_length = 0;
	s->s3->rbuf.left = 0;
	s->s3->rbuf.offset = 0;

	s->state = SSL23_ST_SR_SWITCH_VERSION;
	return 1;
	err:
	return -1;
	}