ssl/s3_both.c

/* 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) 1998-2002 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 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 * ECC cipher suite support in OpenSSL originally developed by
 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project. */

#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>

#include <openssl/buf.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/md5.h>
#include <openssl/obj.h>
#include <openssl/rand.h>
#include <openssl/sha.h>
#include <openssl/x509.h>

#include "ssl_locl.h"

/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
int ssl3_do_write(SSL *s, int type)
	{
	int ret;

	ret=ssl3_write_bytes(s,type,&s->init_buf->data[s->init_off],
	                     s->init_num);
	if (ret < 0) return(-1);
	if (ret == s->init_num)
		{
		if (s->msg_callback)
			s->msg_callback(1, s->version, type, s->init_buf->data, (size_t)(s->init_off + s->init_num), s, s->msg_callback_arg);
		return(1);
		}
	s->init_off+=ret;
	s->init_num-=ret;
	return(0);
	}

int ssl3_send_finished(SSL *s, int a, int b, const char *sender, int slen)
	{
	unsigned char *p;
	int i;
	unsigned long l;

	if (s->state == a)
		{
		p = ssl_handshake_start(s);

		i=s->enc_method->final_finish_mac(s,
			sender,slen,s->s3->tmp.finish_md);
		if (i == 0)
			return 0;
		s->s3->tmp.finish_md_len = i;
		memcpy(p, s->s3->tmp.finish_md, i);
		l=i;

                /* Log the master secret, if logging is enabled. */
                if (!ssl_ctx_log_master_secret(s->ctx,
				s->s3->client_random, SSL3_RANDOM_SIZE,
				s->session->master_key, s->session->master_key_length))
			{
			return 0;
			}

		/* Copy the finished so we can use it for
		 * renegotiation checks */
		if (s->server)
			{
			assert(i <= EVP_MAX_MD_SIZE);
			memcpy(s->s3->previous_server_finished,
				s->s3->tmp.finish_md, i);
			s->s3->previous_server_finished_len = i;
			}
		else
			{
			assert(i <= EVP_MAX_MD_SIZE);
			memcpy(s->s3->previous_client_finished,
				s->s3->tmp.finish_md, i);
			s->s3->previous_client_finished_len = i;
			}

		ssl_set_handshake_header(s, SSL3_MT_FINISHED, l);
		s->state=b;
		}

	/* SSL3_ST_SEND_xxxxxx_HELLO_B */
	return ssl_do_write(s);
	}

/* ssl3_take_mac calculates the Finished MAC for the handshakes messages seen to far. */
static void ssl3_take_mac(SSL *s)
	{
	const char *sender;
	int slen;
	/* If no new cipher setup return immediately: other functions will
	 * set the appropriate error.
	 */
	if (s->s3->tmp.new_cipher == NULL)
		return;
	if (s->state & SSL_ST_CONNECT)
		{
		sender=s->enc_method->server_finished_label;
		slen=s->enc_method->server_finished_label_len;
		}
	else
		{
		sender=s->enc_method->client_finished_label;
		slen=s->enc_method->client_finished_label_len;
		}

	s->s3->tmp.peer_finish_md_len = s->enc_method->final_finish_mac(s,
		sender,slen,s->s3->tmp.peer_finish_md);
	}

int ssl3_get_finished(SSL *s, int a, int b)
	{
	int al,i,ok;
	long n;
	unsigned char *p;

	n=s->method->ssl_get_message(s,
		a,
		b,
		SSL3_MT_FINISHED,
		EVP_MAX_MD_SIZE,
		SSL_GET_MESSAGE_DONT_HASH_MESSAGE,
		&ok);

	if (!ok) return((int)n);

	/* Snapshot the finished hash before incorporating the new message. */
	ssl3_take_mac(s);
	ssl3_hash_current_message(s);

	/* If this occurs, we have missed a message.
	 * TODO(davidben): Is this check now redundant with
	 * SSL3_FLAGS_EXPECT_CCS? */
	if (!s->s3->change_cipher_spec)
		{
		al=SSL_AD_UNEXPECTED_MESSAGE;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_finished, SSL_R_GOT_A_FIN_BEFORE_A_CCS);
		goto f_err;
		}
	s->s3->change_cipher_spec=0;

	p = s->init_msg;
	i = s->s3->tmp.peer_finish_md_len;

	if (i != n)
		{
		al=SSL_AD_DECODE_ERROR;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_finished, SSL_R_BAD_DIGEST_LENGTH);
		goto f_err;
		}

	if (CRYPTO_memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
		{
		al=SSL_AD_DECRYPT_ERROR;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_finished, SSL_R_DIGEST_CHECK_FAILED);
		goto f_err;
		}

	/* Copy the finished so we can use it for renegotiation
	 * checks */
	if (s->server)
		{
		assert(i <= EVP_MAX_MD_SIZE);
		memcpy(s->s3->previous_client_finished,
			s->s3->tmp.peer_finish_md, i);
		s->s3->previous_client_finished_len = i;
		}
	else
		{
		assert(i <= EVP_MAX_MD_SIZE);
		memcpy(s->s3->previous_server_finished,
			s->s3->tmp.peer_finish_md, i);
		s->s3->previous_server_finished_len = i;
		}

	return(1);
f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
	return(0);
	}

/* for these 2 messages, we need to
 * ssl->enc_read_ctx			re-init
 * ssl->s3->read_sequence		zero
 * ssl->s3->read_mac_secret		re-init
 * ssl->session->read_sym_enc		assign
 * ssl->session->read_compression	assign
 * ssl->session->read_hash		assign
 */
int ssl3_send_change_cipher_spec(SSL *s, int a, int b)
	{ 
	unsigned char *p;

	if (s->state == a)
		{
		p=(unsigned char *)s->init_buf->data;
		*p=SSL3_MT_CCS;
		s->init_num=1;
		s->init_off=0;

		s->state=b;
		}

	/* SSL3_ST_CW_CHANGE_B */
	return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
	}

unsigned long ssl3_output_cert_chain(SSL *s, CERT_PKEY *cpk)
	{
	unsigned char *p;
	unsigned long l = 3 + SSL_HM_HEADER_LENGTH(s);

	if (!ssl_add_cert_chain(s, cpk, &l))
		return 0;

	l -= 3 + SSL_HM_HEADER_LENGTH(s);
	p = ssl_handshake_start(s);
	l2n3(l,p);
	l += 3;
	ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE, l);
	return l + SSL_HM_HEADER_LENGTH(s);
	}

/* Obtain handshake message of message type 'mt' (any if mt == -1),
 * maximum acceptable body length 'max'.
 * The first four bytes (msg_type and length) are read in state 'st1',
 * the body is read in state 'stn'.
 */
long ssl3_get_message(SSL *s, int st1, int stn, int mt, long max, int hash_message, int *ok)
	{
	unsigned char *p;
	unsigned long l;
	long n;
	int i,al;

	if (s->s3->tmp.reuse_message)
		{
		/* A SSL_GET_MESSAGE_DONT_HASH_MESSAGE call cannot be combined
		 * with reuse_message; the SSL_GET_MESSAGE_DONT_HASH_MESSAGE
		 * would have to have been applied to the previous call. */
		assert(hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE);
		s->s3->tmp.reuse_message=0;
		if ((mt >= 0) && (s->s3->tmp.message_type != mt))
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_message, SSL_R_UNEXPECTED_MESSAGE);
			goto f_err;
			}
		*ok=1;
		s->state = stn;
		s->init_msg = (uint8_t*)s->init_buf->data + 4;
		s->init_num = (int)s->s3->tmp.message_size;
		return s->init_num;
		}

	p=(unsigned char *)s->init_buf->data;

	if (s->state == st1) /* s->init_num < 4 */
		{
		int skip_message;

		do
			{
			while (s->init_num < 4)
				{
				i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
					&p[s->init_num],4 - s->init_num, 0);
				if (i <= 0)
					{
					s->rwstate=SSL_READING;
					*ok = 0;
					return i;
					}
				s->init_num+=i;
				}
			
			skip_message = 0;
			if (!s->server)
				if (p[0] == SSL3_MT_HELLO_REQUEST)
					/* The server may always send 'Hello Request' messages --
					 * we are doing a handshake anyway now, so ignore them
					 * if their format is correct. Does not count for
					 * 'Finished' MAC. */
					if (p[1] == 0 && p[2] == 0 &&p[3] == 0)
						{
						s->init_num = 0;
						skip_message = 1;

						if (s->msg_callback)
							s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, 4, s, s->msg_callback_arg);
						}
			}
		while (skip_message);

		/* s->init_num == 4 */

		if ((mt >= 0) && (*p != mt))
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_message, SSL_R_UNEXPECTED_MESSAGE);
			goto f_err;
			}
		s->s3->tmp.message_type= *(p++);

		n2l3(p,l);
		if (l > (unsigned long)max)
			{
			al=SSL_AD_ILLEGAL_PARAMETER;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_message, SSL_R_EXCESSIVE_MESSAGE_SIZE);
			goto f_err;
			}
		if (l > (INT_MAX-4)) /* BUF_MEM_grow takes an 'int' parameter */
			{
			al=SSL_AD_ILLEGAL_PARAMETER;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_message, SSL_R_EXCESSIVE_MESSAGE_SIZE);
			goto f_err;
			}
		if (l && !BUF_MEM_grow_clean(s->init_buf,(int)l+4))
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_get_message, ERR_R_BUF_LIB);
			goto err;
			}
		s->s3->tmp.message_size=l;
		s->state=stn;

		s->init_msg = (uint8_t*)s->init_buf->data + 4;
		s->init_num = 0;
		}

	/* next state (stn) */
	p = s->init_msg;
	n = s->s3->tmp.message_size - s->init_num;
	while (n > 0)
		{
		i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,&p[s->init_num],n,0);
		if (i <= 0)
			{
			s->rwstate=SSL_READING;
			*ok = 0;
			return i;
			}
		s->init_num += i;
		n -= i;
		}

	/* Feed this message into MAC computation. */
	if (hash_message != SSL_GET_MESSAGE_DONT_HASH_MESSAGE)
		ssl3_hash_current_message(s);
	if (s->msg_callback)
		s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data, (size_t)s->init_num + 4, s, s->msg_callback_arg);
	*ok=1;
	return s->init_num;
f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
	*ok=0;
	return(-1);
	}

void ssl3_hash_current_message(SSL *s)
	{
	/* The handshake header (different size between DTLS and TLS) is included in the hash. */
	size_t header_len = s->init_msg - (uint8_t *)s->init_buf->data;
	ssl3_finish_mac(s, (uint8_t *)s->init_buf->data, s->init_num + header_len);
	}

/* ssl3_cert_verify_hash is documented as needing EVP_MAX_MD_SIZE because that
 * is sufficient pre-TLS1.2 as well. */
OPENSSL_COMPILE_ASSERT(EVP_MAX_MD_SIZE > MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH,
	combined_tls_hash_fits_in_max);

int ssl3_cert_verify_hash(SSL *s, uint8_t *out, size_t *out_len, const EVP_MD **out_md, EVP_PKEY *pkey)
	{
	/* For TLS v1.2 send signature algorithm and signature using
	 * agreed digest and cached handshake records. Otherwise, use
	 * SHA1 or MD5 + SHA1 depending on key type.  */
	if (SSL_USE_SIGALGS(s))
		{
		const uint8_t *hdata;
		size_t hdatalen;
		EVP_MD_CTX mctx;
		unsigned len;

		if (!BIO_mem_contents(s->s3->handshake_buffer, &hdata, &hdatalen))
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_cert_verify_hash, ERR_R_INTERNAL_ERROR);
			return 0;
			}
		EVP_MD_CTX_init(&mctx);
		if (!EVP_DigestInit_ex(&mctx, *out_md, NULL)
			|| !EVP_DigestUpdate(&mctx, hdata, hdatalen)
			|| !EVP_DigestFinal(&mctx, out, &len))
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_cert_verify_hash, ERR_R_EVP_LIB);
			EVP_MD_CTX_cleanup(&mctx);
			return 0;
			}
		*out_len = len;
		}
	else if (pkey->type == EVP_PKEY_RSA)
		{
		if (s->enc_method->cert_verify_mac(s, NID_md5, out) == 0 ||
			s->enc_method->cert_verify_mac(s,
				NID_sha1, out + MD5_DIGEST_LENGTH) == 0)
			return 0;
		*out_len = MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH;
		*out_md = EVP_md5_sha1();
		}
	else if (pkey->type == EVP_PKEY_EC)
		{
		if (s->enc_method->cert_verify_mac(s, NID_sha1, out) == 0)
			return 0;
		*out_len = SHA_DIGEST_LENGTH;
		*out_md = EVP_sha1();
		}
	else
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_cert_verify_hash, ERR_R_INTERNAL_ERROR);
		return 0;
		}
	return 1;
	}

int ssl_cert_type(X509 *x, EVP_PKEY *pkey)
	{
	EVP_PKEY *pk;
	int ret= -1,i;

	if (pkey == NULL)
		pk=X509_get_pubkey(x);
	else
		pk=pkey;
	if (pk == NULL) goto err;

	i=pk->type;
	if (i == EVP_PKEY_RSA)
		{
		ret=SSL_PKEY_RSA_ENC;
		}
	else if (i == EVP_PKEY_EC)
		{
		ret = SSL_PKEY_ECC;
		}	
		
err:
	if(!pkey) EVP_PKEY_free(pk);
	return(ret);
	}

int ssl_verify_alarm_type(long type)
	{
	int al;

	switch(type)
		{
	case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
	case X509_V_ERR_UNABLE_TO_GET_CRL:
	case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
		al=SSL_AD_UNKNOWN_CA;
		break;
	case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
	case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
	case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
	case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
	case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
	case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
	case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
	case X509_V_ERR_CERT_NOT_YET_VALID:
	case X509_V_ERR_CRL_NOT_YET_VALID:
	case X509_V_ERR_CERT_UNTRUSTED:
	case X509_V_ERR_CERT_REJECTED:
		al=SSL_AD_BAD_CERTIFICATE;
		break;
	case X509_V_ERR_CERT_SIGNATURE_FAILURE:
	case X509_V_ERR_CRL_SIGNATURE_FAILURE:
		al=SSL_AD_DECRYPT_ERROR;
		break;
	case X509_V_ERR_CERT_HAS_EXPIRED:
	case X509_V_ERR_CRL_HAS_EXPIRED:
		al=SSL_AD_CERTIFICATE_EXPIRED;
		break;
	case X509_V_ERR_CERT_REVOKED:
		al=SSL_AD_CERTIFICATE_REVOKED;
		break;
	case X509_V_ERR_OUT_OF_MEM:
		al=SSL_AD_INTERNAL_ERROR;
		break;
	case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
	case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
	case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
	case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
	case X509_V_ERR_CERT_CHAIN_TOO_LONG:
	case X509_V_ERR_PATH_LENGTH_EXCEEDED:
	case X509_V_ERR_INVALID_CA:
		al=SSL_AD_UNKNOWN_CA;
		break;
	case X509_V_ERR_APPLICATION_VERIFICATION:
		al=SSL_AD_HANDSHAKE_FAILURE;
		break;
	case X509_V_ERR_INVALID_PURPOSE:
		al=SSL_AD_UNSUPPORTED_CERTIFICATE;
		break;
	default:
		al=SSL_AD_CERTIFICATE_UNKNOWN;
		break;
		}
	return(al);
	}

int ssl3_setup_read_buffer(SSL *s)
	{
	unsigned char *p;
	size_t len,align=0,headerlen;
	
	if (SSL_IS_DTLS(s))
		headerlen = DTLS1_RT_HEADER_LENGTH;
	else
		headerlen = SSL3_RT_HEADER_LENGTH;

#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
	align = (-SSL3_RT_HEADER_LENGTH)&(SSL3_ALIGN_PAYLOAD-1);
#endif

	if (s->s3->rbuf.buf == NULL)
		{
		len = SSL3_RT_MAX_PLAIN_LENGTH
			+ SSL3_RT_MAX_ENCRYPTED_OVERHEAD
			+ headerlen + align;
		if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
			{
			s->s3->init_extra = 1;
			len += SSL3_RT_MAX_EXTRA;
			}
		if ((p=OPENSSL_malloc(len)) == NULL)
			goto err;
		s->s3->rbuf.buf = p;
		s->s3->rbuf.len = len;
		}

	s->packet= &(s->s3->rbuf.buf[0]);
	return 1;

err:
	OPENSSL_PUT_ERROR(SSL, ssl3_setup_read_buffer, ERR_R_MALLOC_FAILURE);
	return 0;
	}

int ssl3_setup_write_buffer(SSL *s)
	{
	unsigned char *p;
	size_t len,align=0,headerlen;

	if (SSL_IS_DTLS(s))
		headerlen = DTLS1_RT_HEADER_LENGTH + 1;
	else
		headerlen = SSL3_RT_HEADER_LENGTH;

#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
	align = (-SSL3_RT_HEADER_LENGTH)&(SSL3_ALIGN_PAYLOAD-1);
#endif

	if (s->s3->wbuf.buf == NULL)
		{
		len = s->max_send_fragment
			+ SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD
			+ headerlen + align;
		/* Account for 1/n-1 record splitting. */
		if (s->mode & SSL_MODE_CBC_RECORD_SPLITTING)
			len += headerlen + align + 1
				+ SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD;

		if ((p=OPENSSL_malloc(len)) == NULL)
			goto err;
		s->s3->wbuf.buf = p;
		s->s3->wbuf.len = len;
		}

	return 1;

err:
	OPENSSL_PUT_ERROR(SSL, ssl3_setup_write_buffer, ERR_R_MALLOC_FAILURE);
	return 0;
	}


int ssl3_setup_buffers(SSL *s)
	{
	if (!ssl3_setup_read_buffer(s))
		return 0;
	if (!ssl3_setup_write_buffer(s))
		return 0;
	return 1;
	}

int ssl3_release_write_buffer(SSL *s)
	{
	if (s->s3->wbuf.buf != NULL)
		{
		OPENSSL_free(s->s3->wbuf.buf);
		s->s3->wbuf.buf = NULL;
		}
	return 1;
	}

int ssl3_release_read_buffer(SSL *s)
	{
	if (s->s3->rbuf.buf != NULL)
		{
		OPENSSL_free(s->s3->rbuf.buf);
		s->s3->rbuf.buf = NULL;
		}
	return 1;
	}

/* ssl_fill_hello_random fills a client_random or server_random field of length
 * |len|. Returns 0 on failure or 1 on success. */
int ssl_fill_hello_random(SSL *s, int server, uint8_t *result, size_t len) {
  int send_time = 0;

  if (server) {
    send_time = (s->mode & SSL_MODE_SEND_SERVERHELLO_TIME) != 0;
  } else {
    send_time = (s->mode & SSL_MODE_SEND_CLIENTHELLO_TIME) != 0;
  }

  if (send_time) {
    const uint32_t current_time = time(NULL);
    uint8_t *p = result;

    if (len < 4) {
      return 0;
    }
    p[0] = current_time >> 24;
    p[1] = current_time >> 16;
    p[2] = current_time >> 8;
    p[3] = current_time;
    return RAND_bytes(p + 4, len - 4);
  } else {
    return RAND_bytes(result, len);
  }
}