t1_lib.c

/* ssl/t1_lib.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) 1998-2007 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).
 *
 */

#include <stdio.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/ocsp.h>
#include <openssl/rand.h>
#include "ssl_locl.h"

const char tls1_version_str[]="TLSv1" OPENSSL_VERSION_PTEXT;

#ifndef OPENSSL_NO_TLSEXT
static int tls_decrypt_ticket(SSL *s, const unsigned char *tick, int ticklen,
				const unsigned char *sess_id, int sesslen,
				SSL_SESSION **psess);
#endif

/* TODO: add remaining SPP encrypt/decrypt methods */
SSL3_ENC_METHOD SPP_enc_data={
	spp_enc,
	tls1_mac,
	tls1_setup_key_block,
	tls1_generate_master_secret,
	spp_change_cipher_state,
	tls1_final_finish_mac,
	TLS1_FINISH_MAC_LENGTH,
	tls1_cert_verify_mac,
	TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
	TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
	tls1_alert_code,
	tls1_export_keying_material,
	};

SSL3_ENC_METHOD TLSv1_enc_data={
	tls1_enc,
	tls1_mac,
	tls1_setup_key_block,
	tls1_generate_master_secret,
	tls1_change_cipher_state,
	tls1_final_finish_mac,
	TLS1_FINISH_MAC_LENGTH,
	tls1_cert_verify_mac,
	TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
	TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
	tls1_alert_code,
	tls1_export_keying_material,
	};

long tls1_default_timeout(void)
	{
	/* 2 hours, the 24 hours mentioned in the TLSv1 spec
	 * is way too long for http, the cache would over fill */
	return(60*60*2);
	}

int tls1_new(SSL *s)
	{
	if (!ssl3_new(s)) return(0);
	s->method->ssl_clear(s);
	return(1);
	}

void tls1_free(SSL *s)
	{
#ifndef OPENSSL_NO_TLSEXT
	if (s->tlsext_session_ticket)
		{
		OPENSSL_free(s->tlsext_session_ticket);
		}
#endif /* OPENSSL_NO_TLSEXT */
	ssl3_free(s);
	}

void tls1_clear(SSL *s)
	{
	ssl3_clear(s);
	s->version = s->method->version;
	}

#ifndef OPENSSL_NO_EC

static int nid_list[] =
	{
		NID_sect163k1, /* sect163k1 (1) */
		NID_sect163r1, /* sect163r1 (2) */
		NID_sect163r2, /* sect163r2 (3) */
		NID_sect193r1, /* sect193r1 (4) */ 
		NID_sect193r2, /* sect193r2 (5) */ 
		NID_sect233k1, /* sect233k1 (6) */
		NID_sect233r1, /* sect233r1 (7) */ 
		NID_sect239k1, /* sect239k1 (8) */ 
		NID_sect283k1, /* sect283k1 (9) */
		NID_sect283r1, /* sect283r1 (10) */ 
		NID_sect409k1, /* sect409k1 (11) */ 
		NID_sect409r1, /* sect409r1 (12) */
		NID_sect571k1, /* sect571k1 (13) */ 
		NID_sect571r1, /* sect571r1 (14) */ 
		NID_secp160k1, /* secp160k1 (15) */
		NID_secp160r1, /* secp160r1 (16) */ 
		NID_secp160r2, /* secp160r2 (17) */ 
		NID_secp192k1, /* secp192k1 (18) */
		NID_X9_62_prime192v1, /* secp192r1 (19) */ 
		NID_secp224k1, /* secp224k1 (20) */ 
		NID_secp224r1, /* secp224r1 (21) */
		NID_secp256k1, /* secp256k1 (22) */ 
		NID_X9_62_prime256v1, /* secp256r1 (23) */ 
		NID_secp384r1, /* secp384r1 (24) */
		NID_secp521r1  /* secp521r1 (25) */	
	};

static int pref_list[] =
	{
		NID_sect571r1, /* sect571r1 (14) */ 
		NID_sect571k1, /* sect571k1 (13) */ 
		NID_secp521r1, /* secp521r1 (25) */	
		NID_sect409k1, /* sect409k1 (11) */ 
		NID_sect409r1, /* sect409r1 (12) */
		NID_secp384r1, /* secp384r1 (24) */
		NID_sect283k1, /* sect283k1 (9) */
		NID_sect283r1, /* sect283r1 (10) */ 
		NID_secp256k1, /* secp256k1 (22) */ 
		NID_X9_62_prime256v1, /* secp256r1 (23) */ 
		NID_sect239k1, /* sect239k1 (8) */ 
		NID_sect233k1, /* sect233k1 (6) */
		NID_sect233r1, /* sect233r1 (7) */ 
		NID_secp224k1, /* secp224k1 (20) */ 
		NID_secp224r1, /* secp224r1 (21) */
		NID_sect193r1, /* sect193r1 (4) */ 
		NID_sect193r2, /* sect193r2 (5) */ 
		NID_secp192k1, /* secp192k1 (18) */
		NID_X9_62_prime192v1, /* secp192r1 (19) */ 
		NID_sect163k1, /* sect163k1 (1) */
		NID_sect163r1, /* sect163r1 (2) */
		NID_sect163r2, /* sect163r2 (3) */
		NID_secp160k1, /* secp160k1 (15) */
		NID_secp160r1, /* secp160r1 (16) */ 
		NID_secp160r2, /* secp160r2 (17) */ 
	};

int tls1_ec_curve_id2nid(int curve_id)
	{
	/* ECC curves from draft-ietf-tls-ecc-12.txt (Oct. 17, 2005) */
	if ((curve_id < 1) || ((unsigned int)curve_id >
				sizeof(nid_list)/sizeof(nid_list[0])))
		return 0;
	return nid_list[curve_id-1];
	}

int tls1_ec_nid2curve_id(int nid)
	{
	/* ECC curves from draft-ietf-tls-ecc-12.txt (Oct. 17, 2005) */
	switch (nid)
		{
	case NID_sect163k1: /* sect163k1 (1) */
		return 1;
	case NID_sect163r1: /* sect163r1 (2) */
		return 2;
	case NID_sect163r2: /* sect163r2 (3) */
		return 3;
	case NID_sect193r1: /* sect193r1 (4) */ 
		return 4;
	case NID_sect193r2: /* sect193r2 (5) */ 
		return 5;
	case NID_sect233k1: /* sect233k1 (6) */
		return 6;
	case NID_sect233r1: /* sect233r1 (7) */ 
		return 7;
	case NID_sect239k1: /* sect239k1 (8) */ 
		return 8;
	case NID_sect283k1: /* sect283k1 (9) */
		return 9;
	case NID_sect283r1: /* sect283r1 (10) */ 
		return 10;
	case NID_sect409k1: /* sect409k1 (11) */ 
		return 11;
	case NID_sect409r1: /* sect409r1 (12) */
		return 12;
	case NID_sect571k1: /* sect571k1 (13) */ 
		return 13;
	case NID_sect571r1: /* sect571r1 (14) */ 
		return 14;
	case NID_secp160k1: /* secp160k1 (15) */
		return 15;
	case NID_secp160r1: /* secp160r1 (16) */ 
		return 16;
	case NID_secp160r2: /* secp160r2 (17) */ 
		return 17;
	case NID_secp192k1: /* secp192k1 (18) */
		return 18;
	case NID_X9_62_prime192v1: /* secp192r1 (19) */ 
		return 19;
	case NID_secp224k1: /* secp224k1 (20) */ 
		return 20;
	case NID_secp224r1: /* secp224r1 (21) */
		return 21;
	case NID_secp256k1: /* secp256k1 (22) */ 
		return 22;
	case NID_X9_62_prime256v1: /* secp256r1 (23) */ 
		return 23;
	case NID_secp384r1: /* secp384r1 (24) */
		return 24;
	case NID_secp521r1:  /* secp521r1 (25) */	
		return 25;
	default:
		return 0;
		}
	}
#endif /* OPENSSL_NO_EC */

#ifndef OPENSSL_NO_TLSEXT

/* List of supported signature algorithms and hashes. Should make this
 * customisable at some point, for now include everything we support.
 */

#ifdef OPENSSL_NO_RSA
#define tlsext_sigalg_rsa(md) /* */
#else
#define tlsext_sigalg_rsa(md) md, TLSEXT_signature_rsa,
#endif

#ifdef OPENSSL_NO_DSA
#define tlsext_sigalg_dsa(md) /* */
#else
#define tlsext_sigalg_dsa(md) md, TLSEXT_signature_dsa,
#endif

#ifdef OPENSSL_NO_ECDSA
#define tlsext_sigalg_ecdsa(md) /* */
#else
#define tlsext_sigalg_ecdsa(md) md, TLSEXT_signature_ecdsa,
#endif

#define tlsext_sigalg(md) \
		tlsext_sigalg_rsa(md) \
		tlsext_sigalg_dsa(md) \
		tlsext_sigalg_ecdsa(md)

static unsigned char tls12_sigalgs[] = {
#ifndef OPENSSL_NO_SHA512
	tlsext_sigalg(TLSEXT_hash_sha512)
	tlsext_sigalg(TLSEXT_hash_sha384)
#endif
#ifndef OPENSSL_NO_SHA256
	tlsext_sigalg(TLSEXT_hash_sha256)
	tlsext_sigalg(TLSEXT_hash_sha224)
#endif
#ifndef OPENSSL_NO_SHA
	tlsext_sigalg(TLSEXT_hash_sha1)
#endif
};

int tls12_get_req_sig_algs(SSL *s, unsigned char *p)
	{
	size_t slen = sizeof(tls12_sigalgs);
	if (p)
		memcpy(p, tls12_sigalgs, slen);
	return (int)slen;
	}

unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
	{
	int extdatalen=0;
	unsigned char *orig = buf;
	unsigned char *ret = buf;

	/* don't add extensions for SSLv3 unless doing secure renegotiation */
	if (s->client_version == SSL3_VERSION
					&& !s->s3->send_connection_binding)
		return orig;

	ret+=2;

	if (ret>=limit) return NULL; /* this really never occurs, but ... */

        /* Write the SPP proxy list extension to a client hello */
        if (s->slices_len > 0) {
            unsigned char *len_pt;
            int i,char_len,n;
            
            s2n(TLSEXT_TYPE_proxy_list, ret);
            len_pt = ret; /* Save the position to write the length of the ext. */
            ret += 2; /* Then skip it */
                       
            /* Write all of the slice IDs. */
            s1n(s->slices_len, ret);
            for (i = 0; i < s->slices_len; i++) {
                s1n(s->slices[i]->slice_id, ret);
                
                char_len=strlen(s->slices[i]->purpose);
                s1n(char_len, ret);
                memcpy(ret, s->slices[i]->purpose, char_len);
                ret+=char_len;
            }
            /* Now write all of the proxies. */
            s1n(s->proxies_len, ret);
            for (i = 0; i < s->proxies_len; i++) {
#ifdef DEBUG
                printf("Extension writing proxy %d, %s\n", s->proxies[i]->proxy_id, s->proxies[i]->address);
#endif
                s1n(s->proxies[i]->proxy_id, ret);
                
                char_len=strlen(s->proxies[i]->address);
                s1n(char_len, ret);
                memcpy(ret, s->proxies[i]->address, char_len);
                ret+=char_len;                              
                
                s1n(s->proxies[i]->read_slice_ids_len, ret);
                for (n = 0; n < s->proxies[i]->read_slice_ids_len; n++) {
                    s1n(s->proxies[i]->read_slice_ids[n], ret);
                }
                
                s1n(s->proxies[i]->write_slice_ids_len, ret);
                for (n = 0; n < s->proxies[i]->write_slice_ids_len; n++) {
                    s1n(s->proxies[i]->write_slice_ids[n], ret);
                }
            }
            
            /* Write the server address last */
            char_len=strlen(s->spp_server_address);
            s1n(char_len, ret);
            memcpy(ret, s->spp_server_address, char_len);
            ret+=char_len;
            
            /* Now go back and fill in length */
            s2n(ret-len_pt-2, len_pt);
        }
        
 	if (s->tlsext_hostname != NULL)
		{ 
		/* Add TLS extension servername to the Client Hello message */
		unsigned long size_str;
		long lenmax; 

		/* check for enough space.
		   4 for the servername type and entension length
		   2 for servernamelist length
		   1 for the hostname type
		   2 for hostname length
		   + hostname length 
		*/
		   
		if ((lenmax = limit - ret - 9) < 0 
		    || (size_str = strlen(s->tlsext_hostname)) > (unsigned long)lenmax) 
			return NULL;
			
		/* extension type and length */
		s2n(TLSEXT_TYPE_server_name,ret); 
		s2n(size_str+5,ret);
		
		/* length of servername list */
		s2n(size_str+3,ret);
	
		/* hostname type, length and hostname */
		*(ret++) = (unsigned char) TLSEXT_NAMETYPE_host_name;
		s2n(size_str,ret);
		memcpy(ret, s->tlsext_hostname, size_str);
		ret+=size_str;
		}

        /* Add RI if renegotiating */
        if (s->renegotiate)
          {
          int el;
          
          if(!ssl_add_clienthello_renegotiate_ext(s, 0, &el, 0))
              {
              SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
              return NULL;
              }

          if((limit - ret - 4 - el) < 0) return NULL;
          
          s2n(TLSEXT_TYPE_renegotiate,ret);
          s2n(el,ret);

          if(!ssl_add_clienthello_renegotiate_ext(s, ret, &el, el))
              {
              SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
              return NULL;
              }

          ret += el;
        }

#ifndef OPENSSL_NO_SRP
	/* Add SRP username if there is one */
	if (s->srp_ctx.login != NULL)
		{ /* Add TLS extension SRP username to the Client Hello message */

		int login_len = strlen(s->srp_ctx.login);	
		if (login_len > 255 || login_len == 0)
			{
			SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			} 

		/* check for enough space.
		   4 for the srp type type and entension length
		   1 for the srp user identity
		   + srp user identity length 
		*/
		if ((limit - ret - 5 - login_len) < 0) return NULL; 

		/* fill in the extension */
		s2n(TLSEXT_TYPE_srp,ret);
		s2n(login_len+1,ret);
		(*ret++) = (unsigned char) login_len;
		memcpy(ret, s->srp_ctx.login, login_len);
		ret+=login_len;
		}
#endif

#ifndef OPENSSL_NO_EC
	if (s->tlsext_ecpointformatlist != NULL)
		{
		/* Add TLS extension ECPointFormats to the ClientHello message */
		long lenmax; 

		if ((lenmax = limit - ret - 5) < 0) return NULL; 
		if (s->tlsext_ecpointformatlist_length > (unsigned long)lenmax) return NULL;
		if (s->tlsext_ecpointformatlist_length > 255)
			{
			SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			}
		
		s2n(TLSEXT_TYPE_ec_point_formats,ret);
		s2n(s->tlsext_ecpointformatlist_length + 1,ret);
		*(ret++) = (unsigned char) s->tlsext_ecpointformatlist_length;
		memcpy(ret, s->tlsext_ecpointformatlist, s->tlsext_ecpointformatlist_length);
		ret+=s->tlsext_ecpointformatlist_length;
		}
	if (s->tlsext_ellipticcurvelist != NULL)
		{
		/* Add TLS extension EllipticCurves to the ClientHello message */
		long lenmax; 

		if ((lenmax = limit - ret - 6) < 0) return NULL; 
		if (s->tlsext_ellipticcurvelist_length > (unsigned long)lenmax) return NULL;
		if (s->tlsext_ellipticcurvelist_length > 65532)
			{
			SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			}
		
		s2n(TLSEXT_TYPE_elliptic_curves,ret);
		s2n(s->tlsext_ellipticcurvelist_length + 2, ret);

		/* NB: draft-ietf-tls-ecc-12.txt uses a one-byte prefix for
		 * elliptic_curve_list, but the examples use two bytes.
		 * http://www1.ietf.org/mail-archive/web/tls/current/msg00538.html
		 * resolves this to two bytes.
		 */
		s2n(s->tlsext_ellipticcurvelist_length, ret);
		memcpy(ret, s->tlsext_ellipticcurvelist, s->tlsext_ellipticcurvelist_length);
		ret+=s->tlsext_ellipticcurvelist_length;
		}
#endif /* OPENSSL_NO_EC */

	if (!(SSL_get_options(s) & SSL_OP_NO_TICKET))
		{
		int ticklen;
		if (!s->new_session && s->session && s->session->tlsext_tick)
			ticklen = s->session->tlsext_ticklen;
		else if (s->session && s->tlsext_session_ticket &&
			 s->tlsext_session_ticket->data)
			{
			ticklen = s->tlsext_session_ticket->length;
			s->session->tlsext_tick = OPENSSL_malloc(ticklen);
			if (!s->session->tlsext_tick)
				return NULL;
			memcpy(s->session->tlsext_tick,
			       s->tlsext_session_ticket->data,
			       ticklen);
			s->session->tlsext_ticklen = ticklen;
			}
		else
			ticklen = 0;
		if (ticklen == 0 && s->tlsext_session_ticket &&
		    s->tlsext_session_ticket->data == NULL)
			goto skip_ext;
		/* Check for enough room 2 for extension type, 2 for len
 		 * rest for ticket
  		 */
		if ((long)(limit - ret - 4 - ticklen) < 0) return NULL;
		s2n(TLSEXT_TYPE_session_ticket,ret); 
		s2n(ticklen,ret);
		if (ticklen)
			{
			memcpy(ret, s->session->tlsext_tick, ticklen);
			ret += ticklen;
			}
		}
		skip_ext:

	if (TLS1_get_client_version(s) >= TLS1_2_VERSION)
		{
		if ((size_t)(limit - ret) < sizeof(tls12_sigalgs) + 6)
			return NULL; 
		s2n(TLSEXT_TYPE_signature_algorithms,ret);
		s2n(sizeof(tls12_sigalgs) + 2, ret);
		s2n(sizeof(tls12_sigalgs), ret);
		memcpy(ret, tls12_sigalgs, sizeof(tls12_sigalgs));
		ret += sizeof(tls12_sigalgs);
		}

#ifdef TLSEXT_TYPE_opaque_prf_input
	if (s->s3->client_opaque_prf_input != NULL &&
	    s->version != DTLS1_VERSION)
		{
		size_t col = s->s3->client_opaque_prf_input_len;
		
		if ((long)(limit - ret - 6 - col < 0))
			return NULL;
		if (col > 0xFFFD) /* can't happen */
			return NULL;

		s2n(TLSEXT_TYPE_opaque_prf_input, ret); 
		s2n(col + 2, ret);
		s2n(col, ret);
		memcpy(ret, s->s3->client_opaque_prf_input, col);
		ret += col;
		}
#endif

	if (s->tlsext_status_type == TLSEXT_STATUSTYPE_ocsp &&
	    s->version != DTLS1_VERSION)
		{
		int i;
		long extlen, idlen, itmp;
		OCSP_RESPID *id;

		idlen = 0;
		for (i = 0; i < sk_OCSP_RESPID_num(s->tlsext_ocsp_ids); i++)
			{
			id = sk_OCSP_RESPID_value(s->tlsext_ocsp_ids, i);
			itmp = i2d_OCSP_RESPID(id, NULL);
			if (itmp <= 0)
				return NULL;
			idlen += itmp + 2;
			}

		if (s->tlsext_ocsp_exts)
			{
			extlen = i2d_X509_EXTENSIONS(s->tlsext_ocsp_exts, NULL);
			if (extlen < 0)
				return NULL;
			}
		else
			extlen = 0;
			
		if ((long)(limit - ret - 7 - extlen - idlen) < 0) return NULL;
		s2n(TLSEXT_TYPE_status_request, ret);
		if (extlen + idlen > 0xFFF0)
			return NULL;
		s2n(extlen + idlen + 5, ret);
		*(ret++) = TLSEXT_STATUSTYPE_ocsp;
		s2n(idlen, ret);
		for (i = 0; i < sk_OCSP_RESPID_num(s->tlsext_ocsp_ids); i++)
			{
			/* save position of id len */
			unsigned char *q = ret;
			id = sk_OCSP_RESPID_value(s->tlsext_ocsp_ids, i);
			/* skip over id len */
			ret += 2;
			itmp = i2d_OCSP_RESPID(id, &ret);
			/* write id len */
			s2n(itmp, q);
			}
		s2n(extlen, ret);
		if (extlen > 0)
			i2d_X509_EXTENSIONS(s->tlsext_ocsp_exts, &ret);
		}

#ifndef OPENSSL_NO_HEARTBEATS
	/* Add Heartbeat extension */
	if ((limit - ret - 4 - 1) < 0)
		return NULL;
	s2n(TLSEXT_TYPE_heartbeat,ret);
	s2n(1,ret);
	/* Set mode:
	 * 1: peer may send requests
	 * 2: peer not allowed to send requests
	 */
	if (s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_RECV_REQUESTS)
		*(ret++) = SSL_TLSEXT_HB_DONT_SEND_REQUESTS;
	else
		*(ret++) = SSL_TLSEXT_HB_ENABLED;
#endif

#ifndef OPENSSL_NO_NEXTPROTONEG
	if (s->ctx->next_proto_select_cb && !s->s3->tmp.finish_md_len)
		{
		/* The client advertises an emtpy extension to indicate its
		 * support for Next Protocol Negotiation */
		if (limit - ret - 4 < 0)
			return NULL;
		s2n(TLSEXT_TYPE_next_proto_neg,ret);
		s2n(0,ret);
		}
#endif

#ifndef OPENSSL_NO_SRTP
	if(SSL_IS_DTLS(s) && SSL_get_srtp_profiles(s))
                {
                int el;

                ssl_add_clienthello_use_srtp_ext(s, 0, &el, 0);
                
                if((limit - ret - 4 - el) < 0) return NULL;

                s2n(TLSEXT_TYPE_use_srtp,ret);
                s2n(el,ret);

                if(ssl_add_clienthello_use_srtp_ext(s, ret, &el, el))
			{
			SSLerr(SSL_F_SSL_ADD_CLIENTHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			}
                ret += el;
                }
#endif
	/* Add padding to workaround bugs in F5 terminators.
	 * See https://tools.ietf.org/html/draft-agl-tls-padding-03
	 *
	 * NB: because this code works out the length of all existing
	 * extensions it MUST always appear last.
	 */
	if (s->options & SSL_OP_TLSEXT_PADDING)
		{
		int hlen = ret - (unsigned char *)s->init_buf->data;
		/* The code in s23_clnt.c to build ClientHello messages
		 * includes the 5-byte record header in the buffer, while
		 * the code in s3_clnt.c does not.
		 */
		if (s->state == SSL23_ST_CW_CLNT_HELLO_A)
			hlen -= 5;
		if (hlen > 0xff && hlen < 0x200)
			{
			hlen = 0x200 - hlen;
			if (hlen >= 4)
				hlen -= 4;
			else
				hlen = 0;

			s2n(TLSEXT_TYPE_padding, ret);
			s2n(hlen, ret);
			memset(ret, 0, hlen);
			ret += hlen;
			}
		}

	if ((extdatalen = ret-orig-2)== 0) 
		return orig;

	s2n(extdatalen, orig);
	return ret;
	}

unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
	{
	int extdatalen=0;
	unsigned char *orig = buf;
	unsigned char *ret = buf;
#ifndef OPENSSL_NO_NEXTPROTONEG
	int next_proto_neg_seen;
#endif

	/* don't add extensions for SSLv3, unless doing secure renegotiation */
	if (s->version == SSL3_VERSION && !s->s3->send_connection_binding)
		return orig;
	
	ret+=2;
	if (ret>=limit) return NULL; /* this really never occurs, but ... */

	if (!s->hit && s->servername_done == 1 && s->session->tlsext_hostname != NULL)
		{ 
		if ((long)(limit - ret - 4) < 0) return NULL; 

		s2n(TLSEXT_TYPE_server_name,ret);
		s2n(0,ret);
		}

	if(s->s3->send_connection_binding)
        {
          int el;
          
          if(!ssl_add_serverhello_renegotiate_ext(s, 0, &el, 0))
              {
              SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
              return NULL;
              }

          if((limit - ret - 4 - el) < 0) return NULL;
          
          s2n(TLSEXT_TYPE_renegotiate,ret);
          s2n(el,ret);

          if(!ssl_add_serverhello_renegotiate_ext(s, ret, &el, el))
              {
              SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
              return NULL;
              }

          ret += el;
        }

#ifndef OPENSSL_NO_EC
	if (s->tlsext_ecpointformatlist != NULL)
		{
		/* Add TLS extension ECPointFormats to the ServerHello message */
		long lenmax; 

		if ((lenmax = limit - ret - 5) < 0) return NULL; 
		if (s->tlsext_ecpointformatlist_length > (unsigned long)lenmax) return NULL;
		if (s->tlsext_ecpointformatlist_length > 255)
			{
			SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			}
		
		s2n(TLSEXT_TYPE_ec_point_formats,ret);
		s2n(s->tlsext_ecpointformatlist_length + 1,ret);
		*(ret++) = (unsigned char) s->tlsext_ecpointformatlist_length;
		memcpy(ret, s->tlsext_ecpointformatlist, s->tlsext_ecpointformatlist_length);
		ret+=s->tlsext_ecpointformatlist_length;

		}
	/* Currently the server should not respond with a SupportedCurves extension */
#endif /* OPENSSL_NO_EC */

	if (s->tlsext_ticket_expected
		&& !(SSL_get_options(s) & SSL_OP_NO_TICKET)) 
		{ 
		if ((long)(limit - ret - 4) < 0) return NULL; 
		s2n(TLSEXT_TYPE_session_ticket,ret);
		s2n(0,ret);
		}

	if (s->tlsext_status_expected)
		{ 
		if ((long)(limit - ret - 4) < 0) return NULL; 
		s2n(TLSEXT_TYPE_status_request,ret);
		s2n(0,ret);
		}

#ifdef TLSEXT_TYPE_opaque_prf_input
	if (s->s3->server_opaque_prf_input != NULL &&
	    s->version != DTLS1_VERSION)
		{
		size_t sol = s->s3->server_opaque_prf_input_len;
		
		if ((long)(limit - ret - 6 - sol) < 0)
			return NULL;
		if (sol > 0xFFFD) /* can't happen */
			return NULL;

		s2n(TLSEXT_TYPE_opaque_prf_input, ret); 
		s2n(sol + 2, ret);
		s2n(sol, ret);
		memcpy(ret, s->s3->server_opaque_prf_input, sol);
		ret += sol;
		}
#endif

#ifndef OPENSSL_NO_SRTP
	if(SSL_IS_DTLS(s) && s->srtp_profile)
                {
                int el;

                ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0);
                
                if((limit - ret - 4 - el) < 0) return NULL;

                s2n(TLSEXT_TYPE_use_srtp,ret);
                s2n(el,ret);

                if(ssl_add_serverhello_use_srtp_ext(s, ret, &el, el))
			{
			SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
			return NULL;
			}
                ret+=el;
                }
#endif

	if (((s->s3->tmp.new_cipher->id & 0xFFFF)==0x80 || (s->s3->tmp.new_cipher->id & 0xFFFF)==0x81) 
		&& (SSL_get_options(s) & SSL_OP_CRYPTOPRO_TLSEXT_BUG))
		{ const unsigned char cryptopro_ext[36] = {
			0xfd, 0xe8, /*65000*/
			0x00, 0x20, /*32 bytes length*/
			0x30, 0x1e, 0x30, 0x08, 0x06, 0x06, 0x2a, 0x85, 
			0x03,   0x02, 0x02, 0x09, 0x30, 0x08, 0x06, 0x06, 
			0x2a, 0x85, 0x03, 0x02, 0x02, 0x16, 0x30, 0x08, 
			0x06, 0x06, 0x2a, 0x85, 0x03, 0x02, 0x02, 0x17};
			if (limit-ret<36) return NULL;
			memcpy(ret,cryptopro_ext,36);
			ret+=36;

		}

#ifndef OPENSSL_NO_HEARTBEATS
	/* Add Heartbeat extension if we've received one */
	if (s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED)
		{
		if ((limit - ret - 4 - 1) < 0)
			return NULL;
		s2n(TLSEXT_TYPE_heartbeat,ret);
		s2n(1,ret);
		/* Set mode:
		 * 1: peer may send requests
		 * 2: peer not allowed to send requests
		 */
		if (s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_RECV_REQUESTS)
			*(ret++) = SSL_TLSEXT_HB_DONT_SEND_REQUESTS;
		else
			*(ret++) = SSL_TLSEXT_HB_ENABLED;

		}
#endif

#ifndef OPENSSL_NO_NEXTPROTONEG
	next_proto_neg_seen = s->s3->next_proto_neg_seen;
	s->s3->next_proto_neg_seen = 0;
	if (next_proto_neg_seen && s->ctx->next_protos_advertised_cb)
		{
		const unsigned char *npa;
		unsigned int npalen;
		int r;

		r = s->ctx->next_protos_advertised_cb(s, &npa, &npalen, s->ctx->next_protos_advertised_cb_arg);
		if (r == SSL_TLSEXT_ERR_OK)
			{
			if ((long)(limit - ret - 4 - npalen) < 0) return NULL;
			s2n(TLSEXT_TYPE_next_proto_neg,ret);
			s2n(npalen,ret);
			memcpy(ret, npa, npalen);
			ret += npalen;
			s->s3->next_proto_neg_seen = 1;
			}
		}
#endif

	if ((extdatalen = ret-orig-2)== 0) 
		return orig;

	s2n(extdatalen, orig);
	return ret;
	}

#ifndef OPENSSL_NO_EC
/* ssl_check_for_safari attempts to fingerprint Safari using OS X
 * SecureTransport using the TLS extension block in |d|, of length |n|.
 * Safari, since 10.6, sends exactly these extensions, in this order:
 *   SNI,
 *   elliptic_curves
 *   ec_point_formats
 *
 * We wish to fingerprint Safari because they broke ECDHE-ECDSA support in 10.8,
 * but they advertise support. So enabling ECDHE-ECDSA ciphers breaks them.
 * Sadly we cannot differentiate 10.6, 10.7 and 10.8.4 (which work), from
 * 10.8..10.8.3 (which don't work).
 */
static void ssl_check_for_safari(SSL *s, const unsigned char *data, const unsigned char *d, int n) {
	unsigned short type, size;
	static const unsigned char kSafariExtensionsBlock[] = {
		0x00, 0x0a,  /* elliptic_curves extension */
		0x00, 0x08,  /* 8 bytes */
		0x00, 0x06,  /* 6 bytes of curve ids */
		0x00, 0x17,  /* P-256 */
		0x00, 0x18,  /* P-384 */
		0x00, 0x19,  /* P-521 */

		0x00, 0x0b,  /* ec_point_formats */
		0x00, 0x02,  /* 2 bytes */
		0x01,        /* 1 point format */
		0x00,        /* uncompressed */
	};

	/* The following is only present in TLS 1.2 */
	static const unsigned char kSafariTLS12ExtensionsBlock[] = {
		0x00, 0x0d,  /* signature_algorithms */
		0x00, 0x0c,  /* 12 bytes */
		0x00, 0x0a,  /* 10 bytes */
		0x05, 0x01,  /* SHA-384/RSA */
		0x04, 0x01,  /* SHA-256/RSA */
		0x02, 0x01,  /* SHA-1/RSA */
		0x04, 0x03,  /* SHA-256/ECDSA */
		0x02, 0x03,  /* SHA-1/ECDSA */