Example program to test AES-GCM functionality. Used for a workshop

Dependencies:   mbed

Revision:
0:796d0f61a05b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SSL/library/ssl_tls.c	Thu Sep 27 06:34:22 2018 +0000
@@ -0,0 +1,4893 @@
+/*
+ *  SSLv3/TLSv1 shared functions
+ *
+ *  Copyright (C) 2006-2014, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+/*
+ *  The SSL 3.0 specification was drafted by Netscape in 1996,
+ *  and became an IETF standard in 1999.
+ *
+ *  http://wp.netscape.com/eng/ssl3/
+ *  http://www.ietf.org/rfc/rfc2246.txt
+ *  http://www.ietf.org/rfc/rfc4346.txt
+ */
+
+#if !defined(POLARSSL_CONFIG_FILE)
+#include "polarssl/config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
+
+#if defined(POLARSSL_SSL_TLS_C)
+
+#include "polarssl/debug.h"
+#include "polarssl/ssl.h"
+
+#if defined(POLARSSL_X509_CRT_PARSE_C) && \
+    defined(POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE)
+#include "polarssl/oid.h"
+#endif
+
+#if defined(POLARSSL_PLATFORM_C)
+#include "polarssl/platform.h"
+#else
+#define polarssl_malloc     malloc
+#define polarssl_free       free
+#endif
+
+#include <stdlib.h>
+
+#if defined(_MSC_VER) && !defined strcasecmp && !defined(EFIX64) && \
+    !defined(EFI32)
+#define strcasecmp _stricmp
+#endif
+
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
+/*
+ * Convert max_fragment_length codes to length.
+ * RFC 6066 says:
+ *    enum{
+ *        2^9(1), 2^10(2), 2^11(3), 2^12(4), (255)
+ *    } MaxFragmentLength;
+ * and we add 0 -> extension unused
+ */
+static unsigned int mfl_code_to_length[SSL_MAX_FRAG_LEN_INVALID] =
+{
+    SSL_MAX_CONTENT_LEN,    /* SSL_MAX_FRAG_LEN_NONE */
+    512,                    /* SSL_MAX_FRAG_LEN_512  */
+    1024,                   /* SSL_MAX_FRAG_LEN_1024 */
+    2048,                   /* SSL_MAX_FRAG_LEN_2048 */
+    4096,                   /* SSL_MAX_FRAG_LEN_4096 */
+};
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
+
+static int ssl_session_copy( ssl_session *dst, const ssl_session *src )
+{
+    ssl_session_free( dst );
+    memcpy( dst, src, sizeof( ssl_session ) );
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+    if( src->peer_cert != NULL )
+    {
+        int ret;
+
+        dst->peer_cert = (x509_crt *) polarssl_malloc( sizeof(x509_crt) );
+        if( dst->peer_cert == NULL )
+            return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+        x509_crt_init( dst->peer_cert );
+
+        if( ( ret = x509_crt_parse( dst->peer_cert, src->peer_cert->raw.p,
+                                    src->peer_cert->raw.len ) != 0 ) )
+        {
+            polarssl_free( dst->peer_cert );
+            dst->peer_cert = NULL;
+            return( ret );
+        }
+    }
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+    if( src->ticket != NULL )
+    {
+        dst->ticket = (unsigned char *) polarssl_malloc( src->ticket_len );
+        if( dst->ticket == NULL )
+            return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+        memcpy( dst->ticket, src->ticket, src->ticket_len );
+    }
+#endif /* POLARSSL_SSL_SESSION_TICKETS */
+
+    return( 0 );
+}
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+int (*ssl_hw_record_init)(ssl_context *ssl,
+                     const unsigned char *key_enc, const unsigned char *key_dec,
+                     size_t keylen,
+                     const unsigned char *iv_enc,  const unsigned char *iv_dec,
+                     size_t ivlen,
+                     const unsigned char *mac_enc, const unsigned char *mac_dec,
+                     size_t maclen) = NULL;
+int (*ssl_hw_record_activate)(ssl_context *ssl, int direction) = NULL;
+int (*ssl_hw_record_reset)(ssl_context *ssl) = NULL;
+int (*ssl_hw_record_write)(ssl_context *ssl) = NULL;
+int (*ssl_hw_record_read)(ssl_context *ssl) = NULL;
+int (*ssl_hw_record_finish)(ssl_context *ssl) = NULL;
+#endif /* POLARSSL_SSL_HW_RECORD_ACCEL */
+
+/*
+ * Key material generation
+ */
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+static int ssl3_prf( const unsigned char *secret, size_t slen,
+                     const char *label,
+                     const unsigned char *random, size_t rlen,
+                     unsigned char *dstbuf, size_t dlen )
+{
+    size_t i;
+    md5_context md5;
+    sha1_context sha1;
+    unsigned char padding[16];
+    unsigned char sha1sum[20];
+    ((void)label);
+
+    /*
+     *  SSLv3:
+     *    block =
+     *      MD5( secret + SHA1( 'A'    + secret + random ) ) +
+     *      MD5( secret + SHA1( 'BB'   + secret + random ) ) +
+     *      MD5( secret + SHA1( 'CCC'  + secret + random ) ) +
+     *      ...
+     */
+    for( i = 0; i < dlen / 16; i++ )
+    {
+        memset( padding, (unsigned char) ('A' + i), 1 + i );
+
+        sha1_starts( &sha1 );
+        sha1_update( &sha1, padding, 1 + i );
+        sha1_update( &sha1, secret, slen );
+        sha1_update( &sha1, random, rlen );
+        sha1_finish( &sha1, sha1sum );
+
+        md5_starts( &md5 );
+        md5_update( &md5, secret, slen );
+        md5_update( &md5, sha1sum, 20 );
+        md5_finish( &md5, dstbuf + i * 16 );
+    }
+
+    memset( &md5,  0, sizeof( md5  ) );
+    memset( &sha1, 0, sizeof( sha1 ) );
+
+    memset( padding, 0, sizeof( padding ) );
+    memset( sha1sum, 0, sizeof( sha1sum ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1)
+static int tls1_prf( const unsigned char *secret, size_t slen,
+                     const char *label,
+                     const unsigned char *random, size_t rlen,
+                     unsigned char *dstbuf, size_t dlen )
+{
+    size_t nb, hs;
+    size_t i, j, k;
+    const unsigned char *S1, *S2;
+    unsigned char tmp[128];
+    unsigned char h_i[20];
+
+    if( sizeof( tmp ) < 20 + strlen( label ) + rlen )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    hs = ( slen + 1 ) / 2;
+    S1 = secret;
+    S2 = secret + slen - hs;
+
+    nb = strlen( label );
+    memcpy( tmp + 20, label, nb );
+    memcpy( tmp + 20 + nb, random, rlen );
+    nb += rlen;
+
+    /*
+     * First compute P_md5(secret,label+random)[0..dlen]
+     */
+    md5_hmac( S1, hs, tmp + 20, nb, 4 + tmp );
+
+    for( i = 0; i < dlen; i += 16 )
+    {
+        md5_hmac( S1, hs, 4 + tmp, 16 + nb, h_i );
+        md5_hmac( S1, hs, 4 + tmp, 16,  4 + tmp );
+
+        k = ( i + 16 > dlen ) ? dlen % 16 : 16;
+
+        for( j = 0; j < k; j++ )
+            dstbuf[i + j]  = h_i[j];
+    }
+
+    /*
+     * XOR out with P_sha1(secret,label+random)[0..dlen]
+     */
+    sha1_hmac( S2, hs, tmp + 20, nb, tmp );
+
+    for( i = 0; i < dlen; i += 20 )
+    {
+        sha1_hmac( S2, hs, tmp, 20 + nb, h_i );
+        sha1_hmac( S2, hs, tmp, 20,      tmp );
+
+        k = ( i + 20 > dlen ) ? dlen % 20 : 20;
+
+        for( j = 0; j < k; j++ )
+            dstbuf[i + j] = (unsigned char)( dstbuf[i + j] ^ h_i[j] );
+    }
+
+    memset( tmp, 0, sizeof( tmp ) );
+    memset( h_i, 0, sizeof( h_i ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_PROTO_TLS1) || POLARSSL_SSL_PROTO_TLS1_1 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+static int tls_prf_sha256( const unsigned char *secret, size_t slen,
+                           const char *label,
+                           const unsigned char *random, size_t rlen,
+                           unsigned char *dstbuf, size_t dlen )
+{
+    size_t nb;
+    size_t i, j, k;
+    unsigned char tmp[128];
+    unsigned char h_i[32];
+
+    if( sizeof( tmp ) < 32 + strlen( label ) + rlen )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    nb = strlen( label );
+    memcpy( tmp + 32, label, nb );
+    memcpy( tmp + 32 + nb, random, rlen );
+    nb += rlen;
+
+    /*
+     * Compute P_<hash>(secret, label + random)[0..dlen]
+     */
+    sha256_hmac( secret, slen, tmp + 32, nb, tmp, 0 );
+
+    for( i = 0; i < dlen; i += 32 )
+    {
+        sha256_hmac( secret, slen, tmp, 32 + nb, h_i, 0 );
+        sha256_hmac( secret, slen, tmp, 32,      tmp, 0 );
+
+        k = ( i + 32 > dlen ) ? dlen % 32 : 32;
+
+        for( j = 0; j < k; j++ )
+            dstbuf[i + j]  = h_i[j];
+    }
+
+    memset( tmp, 0, sizeof( tmp ) );
+    memset( h_i, 0, sizeof( h_i ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SHA256_C */
+
+#if defined(POLARSSL_SHA512_C)
+static int tls_prf_sha384( const unsigned char *secret, size_t slen,
+                           const char *label,
+                           const unsigned char *random, size_t rlen,
+                           unsigned char *dstbuf, size_t dlen )
+{
+    size_t nb;
+    size_t i, j, k;
+    unsigned char tmp[128];
+    unsigned char h_i[48];
+
+    if( sizeof( tmp ) < 48 + strlen( label ) + rlen )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    nb = strlen( label );
+    memcpy( tmp + 48, label, nb );
+    memcpy( tmp + 48 + nb, random, rlen );
+    nb += rlen;
+
+    /*
+     * Compute P_<hash>(secret, label + random)[0..dlen]
+     */
+    sha512_hmac( secret, slen, tmp + 48, nb, tmp, 1 );
+
+    for( i = 0; i < dlen; i += 48 )
+    {
+        sha512_hmac( secret, slen, tmp, 48 + nb, h_i, 1 );
+        sha512_hmac( secret, slen, tmp, 48,      tmp, 1 );
+
+        k = ( i + 48 > dlen ) ? dlen % 48 : 48;
+
+        for( j = 0; j < k; j++ )
+            dstbuf[i + j]  = h_i[j];
+    }
+
+    memset( tmp, 0, sizeof( tmp ) );
+    memset( h_i, 0, sizeof( h_i ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SHA512_C */
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+static void ssl_update_checksum_start(ssl_context *, const unsigned char *, size_t);
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_1)
+static void ssl_update_checksum_md5sha1(ssl_context *, const unsigned char *, size_t);
+#endif
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+static void ssl_calc_verify_ssl(ssl_context *,unsigned char *);
+static void ssl_calc_finished_ssl(ssl_context *,unsigned char *,int);
+#endif
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1)
+static void ssl_calc_verify_tls(ssl_context *,unsigned char *);
+static void ssl_calc_finished_tls(ssl_context *,unsigned char *,int);
+#endif
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+static void ssl_update_checksum_sha256(ssl_context *, const unsigned char *, size_t);
+static void ssl_calc_verify_tls_sha256(ssl_context *,unsigned char *);
+static void ssl_calc_finished_tls_sha256(ssl_context *,unsigned char *,int);
+#endif
+
+#if defined(POLARSSL_SHA512_C)
+static void ssl_update_checksum_sha384(ssl_context *, const unsigned char *, size_t);
+static void ssl_calc_verify_tls_sha384(ssl_context *,unsigned char *);
+static void ssl_calc_finished_tls_sha384(ssl_context *,unsigned char *,int);
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+int ssl_derive_keys( ssl_context *ssl )
+{
+    int ret = 0;
+    unsigned char tmp[64];
+    unsigned char keyblk[256];
+    unsigned char *key1;
+    unsigned char *key2;
+    unsigned char *mac_enc;
+    unsigned char *mac_dec;
+    size_t iv_copy_len;
+    const cipher_info_t *cipher_info;
+    const md_info_t *md_info;
+
+    ssl_session *session = ssl->session_negotiate;
+    ssl_transform *transform = ssl->transform_negotiate;
+    ssl_handshake_params *handshake = ssl->handshake;
+
+    SSL_DEBUG_MSG( 2, ( "=> derive keys" ) );
+
+    cipher_info = cipher_info_from_type( transform->ciphersuite_info->cipher );
+    if( cipher_info == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "cipher info for %d not found",
+                            transform->ciphersuite_info->cipher ) );
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    md_info = md_info_from_type( transform->ciphersuite_info->mac );
+    if( md_info == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "md info for %d not found",
+                            transform->ciphersuite_info->mac ) );
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    /*
+     * Set appropriate PRF function and other SSL / TLS / TLS1.2 functions
+     */
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+    if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+    {
+        handshake->tls_prf = ssl3_prf;
+        handshake->calc_verify = ssl_calc_verify_ssl;
+        handshake->calc_finished = ssl_calc_finished_ssl;
+    }
+    else
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1)
+    if( ssl->minor_ver < SSL_MINOR_VERSION_3 )
+    {
+        handshake->tls_prf = tls1_prf;
+        handshake->calc_verify = ssl_calc_verify_tls;
+        handshake->calc_finished = ssl_calc_finished_tls;
+    }
+    else
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA512_C)
+    if( ssl->minor_ver == SSL_MINOR_VERSION_3 &&
+        transform->ciphersuite_info->mac == POLARSSL_MD_SHA384 )
+    {
+        handshake->tls_prf = tls_prf_sha384;
+        handshake->calc_verify = ssl_calc_verify_tls_sha384;
+        handshake->calc_finished = ssl_calc_finished_tls_sha384;
+    }
+    else
+#endif
+#if defined(POLARSSL_SHA256_C)
+    if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
+    {
+        handshake->tls_prf = tls_prf_sha256;
+        handshake->calc_verify = ssl_calc_verify_tls_sha256;
+        handshake->calc_finished = ssl_calc_finished_tls_sha256;
+    }
+    else
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+    {
+        SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+    }
+
+    /*
+     * SSLv3:
+     *   master =
+     *     MD5( premaster + SHA1( 'A'   + premaster + randbytes ) ) +
+     *     MD5( premaster + SHA1( 'BB'  + premaster + randbytes ) ) +
+     *     MD5( premaster + SHA1( 'CCC' + premaster + randbytes ) )
+     *
+     * TLSv1+:
+     *   master = PRF( premaster, "master secret", randbytes )[0..47]
+     */
+    if( handshake->resume == 0 )
+    {
+        SSL_DEBUG_BUF( 3, "premaster secret", handshake->premaster,
+                       handshake->pmslen );
+
+        handshake->tls_prf( handshake->premaster, handshake->pmslen,
+                            "master secret",
+                            handshake->randbytes, 64, session->master, 48 );
+
+        memset( handshake->premaster, 0, sizeof( handshake->premaster ) );
+    }
+    else
+        SSL_DEBUG_MSG( 3, ( "no premaster (session resumed)" ) );
+
+    /*
+     * Swap the client and server random values.
+     */
+    memcpy( tmp, handshake->randbytes, 64 );
+    memcpy( handshake->randbytes, tmp + 32, 32 );
+    memcpy( handshake->randbytes + 32, tmp, 32 );
+    memset( tmp, 0, sizeof( tmp ) );
+
+    /*
+     *  SSLv3:
+     *    key block =
+     *      MD5( master + SHA1( 'A'    + master + randbytes ) ) +
+     *      MD5( master + SHA1( 'BB'   + master + randbytes ) ) +
+     *      MD5( master + SHA1( 'CCC'  + master + randbytes ) ) +
+     *      MD5( master + SHA1( 'DDDD' + master + randbytes ) ) +
+     *      ...
+     *
+     *  TLSv1:
+     *    key block = PRF( master, "key expansion", randbytes )
+     */
+    handshake->tls_prf( session->master, 48, "key expansion",
+                        handshake->randbytes, 64, keyblk, 256 );
+
+    SSL_DEBUG_MSG( 3, ( "ciphersuite = %s",
+                   ssl_get_ciphersuite_name( session->ciphersuite ) ) );
+    SSL_DEBUG_BUF( 3, "master secret", session->master, 48 );
+    SSL_DEBUG_BUF( 4, "random bytes", handshake->randbytes, 64 );
+    SSL_DEBUG_BUF( 4, "key block", keyblk, 256 );
+
+    memset( handshake->randbytes, 0, sizeof( handshake->randbytes ) );
+
+    /*
+     * Determine the appropriate key, IV and MAC length.
+     */
+
+    if( cipher_info->mode == POLARSSL_MODE_GCM )
+    {
+        transform->keylen = cipher_info->key_length;
+        transform->keylen /= 8;
+        transform->minlen = 1;
+        transform->ivlen = 12;
+        transform->fixed_ivlen = 4;
+        transform->maclen = 0;
+    }
+    else
+    {
+        if( md_info->type != POLARSSL_MD_NONE )
+        {
+            int ret;
+
+            if( ( ret = md_init_ctx( &transform->md_ctx_enc, md_info ) ) != 0 )
+            {
+                SSL_DEBUG_RET( 1, "md_init_ctx", ret );
+                return( ret );
+            }
+
+            if( ( ret = md_init_ctx( &transform->md_ctx_dec, md_info ) ) != 0 )
+            {
+                SSL_DEBUG_RET( 1, "md_init_ctx", ret );
+                return( ret );
+            }
+
+            transform->maclen = md_get_size( md_info );
+
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
+            /*
+             * If HMAC is to be truncated, we shall keep the leftmost bytes,
+             * (rfc 6066 page 13 or rfc 2104 section 4),
+             * so we only need to adjust the length here.
+             */
+            if( session->trunc_hmac == SSL_TRUNC_HMAC_ENABLED )
+                transform->maclen = SSL_TRUNCATED_HMAC_LEN;
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
+        }
+
+        transform->keylen = cipher_info->key_length;
+        transform->keylen /= 8;
+        transform->ivlen = cipher_info->iv_size;
+
+        transform->minlen = transform->keylen;
+        if( transform->minlen < transform->maclen )
+        {
+            if( cipher_info->mode == POLARSSL_MODE_STREAM )
+                transform->minlen = transform->maclen;
+            else
+                transform->minlen += transform->keylen;
+        }
+    }
+
+    SSL_DEBUG_MSG( 3, ( "keylen: %d, minlen: %d, ivlen: %d, maclen: %d",
+                   transform->keylen, transform->minlen, transform->ivlen,
+                   transform->maclen ) );
+
+    /*
+     * Finally setup the cipher contexts, IVs and MAC secrets.
+     */
+    if( ssl->endpoint == SSL_IS_CLIENT )
+    {
+        key1 = keyblk + transform->maclen * 2;
+        key2 = keyblk + transform->maclen * 2 + transform->keylen;
+
+        mac_enc = keyblk;
+        mac_dec = keyblk + transform->maclen;
+
+        /*
+         * This is not used in TLS v1.1.
+         */
+        iv_copy_len = ( transform->fixed_ivlen ) ?
+                            transform->fixed_ivlen : transform->ivlen;
+        memcpy( transform->iv_enc, key2 + transform->keylen,  iv_copy_len );
+        memcpy( transform->iv_dec, key2 + transform->keylen + iv_copy_len,
+                iv_copy_len );
+    }
+    else
+    {
+        key1 = keyblk + transform->maclen * 2 + transform->keylen;
+        key2 = keyblk + transform->maclen * 2;
+
+        mac_enc = keyblk + transform->maclen;
+        mac_dec = keyblk;
+
+        /*
+         * This is not used in TLS v1.1.
+         */
+        iv_copy_len = ( transform->fixed_ivlen ) ?
+                            transform->fixed_ivlen : transform->ivlen;
+        memcpy( transform->iv_dec, key1 + transform->keylen,  iv_copy_len );
+        memcpy( transform->iv_enc, key1 + transform->keylen + iv_copy_len,
+                iv_copy_len );
+    }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+    if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+    {
+        if( transform->maclen > sizeof transform->mac_enc )
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+        }
+
+        memcpy( transform->mac_enc, mac_enc, transform->maclen );
+        memcpy( transform->mac_dec, mac_dec, transform->maclen );
+    }
+    else
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_2)
+    if( ssl->minor_ver >= SSL_MINOR_VERSION_1 )
+    {
+        md_hmac_starts( &transform->md_ctx_enc, mac_enc, transform->maclen );
+        md_hmac_starts( &transform->md_ctx_dec, mac_dec, transform->maclen );
+    }
+    else
+#endif
+    {
+        SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+    }
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_init != NULL)
+    {
+        int ret = 0;
+
+        SSL_DEBUG_MSG( 2, ( "going for ssl_hw_record_init()" ) );
+
+        if( ( ret = ssl_hw_record_init( ssl, key1, key2, transform->keylen,
+                                        transform->iv_enc, transform->iv_dec,
+                                        iv_copy_len,
+                                        mac_enc, mac_dec,
+                                        transform->maclen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_init", ret );
+            return POLARSSL_ERR_SSL_HW_ACCEL_FAILED;
+        }
+    }
+#endif /* POLARSSL_SSL_HW_RECORD_ACCEL */
+
+    if( ( ret = cipher_init_ctx( &transform->cipher_ctx_enc,
+                                 cipher_info ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "cipher_init_ctx", ret );
+        return( ret );
+    }
+
+    if( ( ret = cipher_init_ctx( &transform->cipher_ctx_dec,
+                                 cipher_info ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "cipher_init_ctx", ret );
+        return( ret );
+    }
+
+    if( ( ret = cipher_setkey( &transform->cipher_ctx_enc, key1,
+                               cipher_info->key_length,
+                               POLARSSL_ENCRYPT ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "cipher_setkey", ret );
+        return( ret );
+    }
+
+    if( ( ret = cipher_setkey( &transform->cipher_ctx_dec, key2,
+                               cipher_info->key_length,
+                               POLARSSL_DECRYPT ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "cipher_setkey", ret );
+        return( ret );
+    }
+
+#if defined(POLARSSL_CIPHER_MODE_CBC)
+    if( cipher_info->mode == POLARSSL_MODE_CBC )
+    {
+        if( ( ret = cipher_set_padding_mode( &transform->cipher_ctx_enc,
+                                             POLARSSL_PADDING_NONE ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_padding_mode", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_set_padding_mode( &transform->cipher_ctx_dec,
+                                             POLARSSL_PADDING_NONE ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_padding_mode", ret );
+            return( ret );
+        }
+    }
+#endif /* POLARSSL_CIPHER_MODE_CBC */
+
+    memset( keyblk, 0, sizeof( keyblk ) );
+
+#if defined(POLARSSL_ZLIB_SUPPORT)
+    // Initialize compression
+    //
+    if( session->compression == SSL_COMPRESS_DEFLATE )
+    {
+        if( ssl->compress_buf == NULL )
+        {
+            SSL_DEBUG_MSG( 3, ( "Allocating compression buffer" ) );
+            ssl->compress_buf = polarssl_malloc( SSL_BUFFER_LEN );
+            if( ssl->compress_buf == NULL )
+            {
+                SSL_DEBUG_MSG( 1, ( "malloc(%d bytes) failed",
+                                    SSL_BUFFER_LEN ) );
+                return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+            }
+        }
+
+        SSL_DEBUG_MSG( 3, ( "Initializing zlib states" ) );
+
+        memset( &transform->ctx_deflate, 0, sizeof( transform->ctx_deflate ) );
+        memset( &transform->ctx_inflate, 0, sizeof( transform->ctx_inflate ) );
+
+        if( deflateInit( &transform->ctx_deflate,
+                         Z_DEFAULT_COMPRESSION )   != Z_OK ||
+            inflateInit( &transform->ctx_inflate ) != Z_OK )
+        {
+            SSL_DEBUG_MSG( 1, ( "Failed to initialize compression" ) );
+            return( POLARSSL_ERR_SSL_COMPRESSION_FAILED );
+        }
+    }
+#endif /* POLARSSL_ZLIB_SUPPORT */
+
+    SSL_DEBUG_MSG( 2, ( "<= derive keys" ) );
+
+    return( 0 );
+}
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+void ssl_calc_verify_ssl( ssl_context *ssl, unsigned char hash[36] )
+{
+    md5_context md5;
+    sha1_context sha1;
+    unsigned char pad_1[48];
+    unsigned char pad_2[48];
+
+    SSL_DEBUG_MSG( 2, ( "=> calc verify ssl" ) );
+
+    memcpy( &md5 , &ssl->handshake->fin_md5 , sizeof(md5_context)  );
+    memcpy( &sha1, &ssl->handshake->fin_sha1, sizeof(sha1_context) );
+
+    memset( pad_1, 0x36, 48 );
+    memset( pad_2, 0x5C, 48 );
+
+    md5_update( &md5, ssl->session_negotiate->master, 48 );
+    md5_update( &md5, pad_1, 48 );
+    md5_finish( &md5, hash );
+
+    md5_starts( &md5 );
+    md5_update( &md5, ssl->session_negotiate->master, 48 );
+    md5_update( &md5, pad_2, 48 );
+    md5_update( &md5, hash,  16 );
+    md5_finish( &md5, hash );
+
+    sha1_update( &sha1, ssl->session_negotiate->master, 48 );
+    sha1_update( &sha1, pad_1, 40 );
+    sha1_finish( &sha1, hash + 16 );
+
+    sha1_starts( &sha1 );
+    sha1_update( &sha1, ssl->session_negotiate->master, 48 );
+    sha1_update( &sha1, pad_2, 40 );
+    sha1_update( &sha1, hash + 16, 20 );
+    sha1_finish( &sha1, hash + 16 );
+
+    SSL_DEBUG_BUF( 3, "calculated verify result", hash, 36 );
+    SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
+
+    return;
+}
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1)
+void ssl_calc_verify_tls( ssl_context *ssl, unsigned char hash[36] )
+{
+    md5_context md5;
+    sha1_context sha1;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc verify tls" ) );
+
+    memcpy( &md5 , &ssl->handshake->fin_md5 , sizeof(md5_context)  );
+    memcpy( &sha1, &ssl->handshake->fin_sha1, sizeof(sha1_context) );
+
+     md5_finish( &md5,  hash );
+    sha1_finish( &sha1, hash + 16 );
+
+    SSL_DEBUG_BUF( 3, "calculated verify result", hash, 36 );
+    SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
+
+    return;
+}
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+void ssl_calc_verify_tls_sha256( ssl_context *ssl, unsigned char hash[32] )
+{
+    sha256_context sha256;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc verify sha256" ) );
+
+    memcpy( &sha256, &ssl->handshake->fin_sha256, sizeof(sha256_context) );
+    sha256_finish( &sha256, hash );
+
+    SSL_DEBUG_BUF( 3, "calculated verify result", hash, 32 );
+    SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
+
+    return;
+}
+#endif /* POLARSSL_SHA256_C */
+
+#if defined(POLARSSL_SHA512_C)
+void ssl_calc_verify_tls_sha384( ssl_context *ssl, unsigned char hash[48] )
+{
+    sha512_context sha512;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc verify sha384" ) );
+
+    memcpy( &sha512, &ssl->handshake->fin_sha512, sizeof(sha512_context) );
+    sha512_finish( &sha512, hash );
+
+    SSL_DEBUG_BUF( 3, "calculated verify result", hash, 48 );
+    SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
+
+    return;
+}
+#endif /* POLARSSL_SHA512_C */
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
+int ssl_psk_derive_premaster( ssl_context *ssl, key_exchange_type_t key_ex )
+{
+    unsigned char *p = ssl->handshake->premaster;
+    unsigned char *end = p + sizeof( ssl->handshake->premaster );
+
+    /*
+     * PMS = struct {
+     *     opaque other_secret<0..2^16-1>;
+     *     opaque psk<0..2^16-1>;
+     * };
+     * with "other_secret" depending on the particular key exchange
+     */
+#if defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED)
+    if( key_ex == POLARSSL_KEY_EXCHANGE_PSK )
+    {
+        if( end - p < 2 + (int) ssl->psk_len )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+        *(p++) = (unsigned char)( ssl->psk_len >> 8 );
+        *(p++) = (unsigned char)( ssl->psk_len      );
+        p += ssl->psk_len;
+    }
+    else
+#endif /* POLARSSL_KEY_EXCHANGE_PSK_ENABLED */
+#if defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)
+    if( key_ex == POLARSSL_KEY_EXCHANGE_RSA_PSK )
+    {
+        /*
+         * other_secret already set by the ClientKeyExchange message,
+         * and is 48 bytes long
+         */
+        *p++ = 0;
+        *p++ = 48;
+        p += 48;
+    }
+    else
+#endif /* POLARSSL_KEY_EXCHANGE_RSA_PKS_ENABLED */
+#if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
+    if( key_ex == POLARSSL_KEY_EXCHANGE_DHE_PSK )
+    {
+        int ret;
+        size_t len = ssl->handshake->dhm_ctx.len;
+
+        if( end - p < 2 + (int) len )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+        *(p++) = (unsigned char)( len >> 8 );
+        *(p++) = (unsigned char)( len );
+        if( ( ret = dhm_calc_secret( &ssl->handshake->dhm_ctx,
+                                      p, &len, ssl->f_rng, ssl->p_rng ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "dhm_calc_secret", ret );
+            return( ret );
+        }
+        p += len;
+
+        SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K  );
+    }
+    else
+#endif /* POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */
+#if defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
+    if( key_ex == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
+    {
+        int ret;
+        size_t zlen;
+
+        if( ( ret = ecdh_calc_secret( &ssl->handshake->ecdh_ctx, &zlen,
+                                       p + 2, end - (p + 2),
+                                       ssl->f_rng, ssl->p_rng ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ecdh_calc_secret", ret );
+            return( ret );
+        }
+
+        *(p++) = (unsigned char)( zlen >> 8 );
+        *(p++) = (unsigned char)( zlen      );
+        p += zlen;
+
+        SSL_DEBUG_MPI( 3, "ECDH: z", &ssl->handshake->ecdh_ctx.z );
+    }
+    else
+#endif /* POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
+    {
+        SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+    }
+
+    /* opaque psk<0..2^16-1>; */
+    if( end - p < 2 + (int) ssl->psk_len )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    *(p++) = (unsigned char)( ssl->psk_len >> 8 );
+    *(p++) = (unsigned char)( ssl->psk_len      );
+    memcpy( p, ssl->psk, ssl->psk_len );
+    p += ssl->psk_len;
+
+    ssl->handshake->pmslen = p - ssl->handshake->premaster;
+
+    return( 0 );
+}
+#endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+/*
+ * SSLv3.0 MAC functions
+ */
+static void ssl_mac( md_context_t *md_ctx, unsigned char *secret,
+                     unsigned char *buf, size_t len,
+                     unsigned char *ctr, int type )
+{
+    unsigned char header[11];
+    unsigned char padding[48];
+    int padlen = 0;
+    int md_size = md_get_size( md_ctx->md_info );
+    int md_type = md_get_type( md_ctx->md_info );
+
+    if( md_type == POLARSSL_MD_MD5 )
+        padlen = 48;
+    else if( md_type == POLARSSL_MD_SHA1 )
+        padlen = 40;
+    else if( md_type == POLARSSL_MD_SHA256 )
+        padlen = 32;
+    else if( md_type == POLARSSL_MD_SHA384 )
+        padlen = 16;
+
+    memcpy( header, ctr, 8 );
+    header[ 8] = (unsigned char)  type;
+    header[ 9] = (unsigned char)( len >> 8 );
+    header[10] = (unsigned char)( len      );
+
+    memset( padding, 0x36, padlen );
+    md_starts( md_ctx );
+    md_update( md_ctx, secret,  md_size );
+    md_update( md_ctx, padding, padlen  );
+    md_update( md_ctx, header,  11      );
+    md_update( md_ctx, buf,     len     );
+    md_finish( md_ctx, buf +    len     );
+
+    memset( padding, 0x5C, padlen );
+    md_starts( md_ctx );
+    md_update( md_ctx, secret,    md_size );
+    md_update( md_ctx, padding,   padlen  );
+    md_update( md_ctx, buf + len, md_size );
+    md_finish( md_ctx, buf + len          );
+}
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+
+/*
+ * Encryption/decryption functions
+ */
+static int ssl_encrypt_buf( ssl_context *ssl )
+{
+    size_t i;
+
+    SSL_DEBUG_MSG( 2, ( "=> encrypt buf" ) );
+
+    /*
+     * Add MAC before encrypt, except for GCM
+     */
+#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) ||     \
+    ( defined(POLARSSL_CIPHER_MODE_CBC) &&                                  \
+      ( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
+    if( ssl->transform_out->cipher_ctx_enc.cipher_info->mode !=
+                                                        POLARSSL_MODE_GCM )
+    {
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+        if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+        {
+            ssl_mac( &ssl->transform_out->md_ctx_enc,
+                      ssl->transform_out->mac_enc,
+                      ssl->out_msg, ssl->out_msglen,
+                      ssl->out_ctr, ssl->out_msgtype );
+        }
+        else
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+        defined(POLARSSL_SSL_PROTO_TLS1_2)
+        if( ssl->minor_ver >= SSL_MINOR_VERSION_1 )
+        {
+            md_hmac_update( &ssl->transform_out->md_ctx_enc, ssl->out_ctr, 13 );
+            md_hmac_update( &ssl->transform_out->md_ctx_enc,
+                             ssl->out_msg, ssl->out_msglen );
+            md_hmac_finish( &ssl->transform_out->md_ctx_enc,
+                             ssl->out_msg + ssl->out_msglen );
+            md_hmac_reset( &ssl->transform_out->md_ctx_enc );
+        }
+        else
+#endif
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+        }
+
+        SSL_DEBUG_BUF( 4, "computed mac",
+                       ssl->out_msg + ssl->out_msglen,
+                       ssl->transform_out->maclen );
+
+        ssl->out_msglen += ssl->transform_out->maclen;
+    }
+#endif /* GCM not the only option */
+
+    /*
+     * Encrypt
+     */
+#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER)
+    if( ssl->transform_out->cipher_ctx_enc.cipher_info->mode ==
+                                                        POLARSSL_MODE_STREAM )
+    {
+        int ret;
+        size_t olen = 0;
+
+        SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %d, "
+                            "including %d bytes of padding",
+                       ssl->out_msglen, 0 ) );
+
+        SSL_DEBUG_BUF( 4, "before encrypt: output payload",
+                       ssl->out_msg, ssl->out_msglen );
+
+        if( ( ret = cipher_reset( &ssl->transform_out->cipher_ctx_enc ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_reset", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_set_iv( &ssl->transform_out->cipher_ctx_enc,
+                                   ssl->transform_out->iv_enc,
+                                   ssl->transform_out->ivlen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_iv", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_out->cipher_ctx_enc,
+                                   ssl->out_msg, ssl->out_msglen, ssl->out_msg,
+                                   &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_update", ret );
+            return( ret );
+        }
+
+        if( ssl->out_msglen != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect %d %d",
+                                ssl->out_msglen, olen ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+
+        if( ( ret = cipher_finish( &ssl->transform_out->cipher_ctx_enc,
+                                   ssl->out_msg + olen, &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_finish", ret );
+            return( ret );
+        }
+
+        if( 0 != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect %d %d",
+                                0, olen ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+    }
+    else
+#endif /* POLARSSL_ARC4_C || POLARSSL_CIPHER_NULL_CIPHER */
+#if defined(POLARSSL_GCM_C)
+    if( ssl->transform_out->cipher_ctx_enc.cipher_info->mode ==
+                                                        POLARSSL_MODE_GCM )
+    {
+        size_t enc_msglen, olen, totlen;
+        unsigned char *enc_msg;
+        unsigned char add_data[13];
+        int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+
+        memcpy( add_data, ssl->out_ctr, 8 );
+        add_data[8]  = ssl->out_msgtype;
+        add_data[9]  = ssl->major_ver;
+        add_data[10] = ssl->minor_ver;
+        add_data[11] = ( ssl->out_msglen >> 8 ) & 0xFF;
+        add_data[12] = ssl->out_msglen & 0xFF;
+
+        SSL_DEBUG_BUF( 4, "additional data used for AEAD",
+                       add_data, 13 );
+
+        /*
+         * Generate IV
+         */
+        ret = ssl->f_rng( ssl->p_rng,
+                ssl->transform_out->iv_enc + ssl->transform_out->fixed_ivlen,
+                ssl->transform_out->ivlen - ssl->transform_out->fixed_ivlen );
+        if( ret != 0 )
+            return( ret );
+
+        memcpy( ssl->out_iv,
+                ssl->transform_out->iv_enc + ssl->transform_out->fixed_ivlen,
+                ssl->transform_out->ivlen - ssl->transform_out->fixed_ivlen );
+
+        SSL_DEBUG_BUF( 4, "IV used", ssl->out_iv,
+                ssl->transform_out->ivlen - ssl->transform_out->fixed_ivlen );
+
+        /*
+         * Fix pointer positions and message length with added IV
+         */
+        enc_msg = ssl->out_msg;
+        enc_msglen = ssl->out_msglen;
+        ssl->out_msglen += ssl->transform_out->ivlen -
+                           ssl->transform_out->fixed_ivlen;
+
+        SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %d, "
+                            "including %d bytes of padding",
+                       ssl->out_msglen, 0 ) );
+
+        SSL_DEBUG_BUF( 4, "before encrypt: output payload",
+                       ssl->out_msg, ssl->out_msglen );
+
+        /*
+         * Encrypt
+         */
+        if( ( ret = cipher_set_iv( &ssl->transform_out->cipher_ctx_enc,
+                                    ssl->transform_out->iv_enc,
+                                    ssl->transform_out->ivlen ) ) != 0 ||
+            ( ret = cipher_reset( &ssl->transform_out->cipher_ctx_enc ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        if( ( ret = cipher_update_ad( &ssl->transform_out->cipher_ctx_enc,
+                                      add_data, 13 ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_out->cipher_ctx_enc,
+                                   enc_msg, enc_msglen,
+                                   enc_msg, &olen ) ) != 0 )
+        {
+            return( ret );
+        }
+        totlen = olen;
+
+        if( ( ret = cipher_finish( &ssl->transform_out->cipher_ctx_enc,
+                                   enc_msg + olen, &olen ) ) != 0 )
+        {
+            return( ret );
+        }
+        totlen += olen;
+
+        if( totlen != enc_msglen )
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( -1 );
+        }
+
+        /*
+         * Authenticate
+         */
+        ssl->out_msglen += 16;
+
+        if( ( ret = cipher_write_tag( &ssl->transform_out->cipher_ctx_enc,
+                                      enc_msg + enc_msglen, 16 ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        SSL_DEBUG_BUF( 4, "after encrypt: tag", enc_msg + enc_msglen, 16 );
+    }
+    else
+#endif /* POLARSSL_GCM_C */
+#if defined(POLARSSL_CIPHER_MODE_CBC) &&                                    \
+    ( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) )
+    if( ssl->transform_out->cipher_ctx_enc.cipher_info->mode ==
+                                                        POLARSSL_MODE_CBC )
+    {
+        int ret;
+        unsigned char *enc_msg;
+        size_t enc_msglen, padlen, olen = 0;
+
+        padlen = ssl->transform_out->ivlen - ( ssl->out_msglen + 1 ) %
+                 ssl->transform_out->ivlen;
+        if( padlen == ssl->transform_out->ivlen )
+            padlen = 0;
+
+        for( i = 0; i <= padlen; i++ )
+            ssl->out_msg[ssl->out_msglen + i] = (unsigned char) padlen;
+
+        ssl->out_msglen += padlen + 1;
+
+        enc_msglen = ssl->out_msglen;
+        enc_msg = ssl->out_msg;
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_1) || defined(POLARSSL_SSL_PROTO_TLS1_2)
+        /*
+         * Prepend per-record IV for block cipher in TLS v1.1 and up as per
+         * Method 1 (6.2.3.2. in RFC4346 and RFC5246)
+         */
+        if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
+        {
+            /*
+             * Generate IV
+             */
+            int ret = ssl->f_rng( ssl->p_rng, ssl->transform_out->iv_enc,
+                                  ssl->transform_out->ivlen );
+            if( ret != 0 )
+                return( ret );
+
+            memcpy( ssl->out_iv, ssl->transform_out->iv_enc,
+                    ssl->transform_out->ivlen );
+
+            /*
+             * Fix pointer positions and message length with added IV
+             */
+            enc_msg = ssl->out_msg;
+            enc_msglen = ssl->out_msglen;
+            ssl->out_msglen += ssl->transform_out->ivlen;
+        }
+#endif /* POLARSSL_SSL_PROTO_TLS1_1 || POLARSSL_SSL_PROTO_TLS1_2 */
+
+        SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %d, "
+                            "including %d bytes of IV and %d bytes of padding",
+                            ssl->out_msglen, ssl->transform_out->ivlen,
+                            padlen + 1 ) );
+
+        SSL_DEBUG_BUF( 4, "before encrypt: output payload",
+                       ssl->out_iv, ssl->out_msglen );
+
+        if( ( ret = cipher_reset( &ssl->transform_out->cipher_ctx_enc ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_reset", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_set_iv( &ssl->transform_out->cipher_ctx_enc,
+                                   ssl->transform_out->iv_enc,
+                                   ssl->transform_out->ivlen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_iv", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_out->cipher_ctx_enc,
+                                   enc_msg, enc_msglen, enc_msg,
+                                   &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_update", ret );
+            return( ret );
+        }
+
+        enc_msglen -= olen;
+
+        if( ( ret = cipher_finish( &ssl->transform_out->cipher_ctx_enc,
+                                   enc_msg + olen, &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_finish", ret );
+            return( ret );
+        }
+
+        if( enc_msglen != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect %d %d",
+                                enc_msglen, olen ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1)
+        if( ssl->minor_ver < SSL_MINOR_VERSION_2 )
+        {
+            /*
+             * Save IV in SSL3 and TLS1
+             */
+            memcpy( ssl->transform_out->iv_enc,
+                    ssl->transform_out->cipher_ctx_enc.iv,
+                    ssl->transform_out->ivlen );
+        }
+#endif
+    }
+    else
+#endif /* POLARSSL_CIPHER_MODE_CBC &&
+          ( POLARSSL_AES_C || POLARSSL_CAMELLIA_C ) */
+    {
+        SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+    }
+
+    for( i = 8; i > 0; i-- )
+        if( ++ssl->out_ctr[i - 1] != 0 )
+            break;
+
+    /* The loops goes to its end iff the counter is wrapping */
+    if( i == 0 )
+    {
+        SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) );
+        return( POLARSSL_ERR_SSL_COUNTER_WRAPPING );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= encrypt buf" ) );
+
+    return( 0 );
+}
+
+#define POLARSSL_SSL_MAX_MAC_SIZE   48
+
+static int ssl_decrypt_buf( ssl_context *ssl )
+{
+    size_t i;
+#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) ||     \
+    ( defined(POLARSSL_CIPHER_MODE_CBC) &&                                  \
+      ( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
+    size_t padlen = 0, correct = 1;
+#endif
+
+    SSL_DEBUG_MSG( 2, ( "=> decrypt buf" ) );
+
+    if( ssl->in_msglen < ssl->transform_in->minlen )
+    {
+        SSL_DEBUG_MSG( 1, ( "in_msglen (%d) < minlen (%d)",
+                       ssl->in_msglen, ssl->transform_in->minlen ) );
+        return( POLARSSL_ERR_SSL_INVALID_MAC );
+    }
+
+#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER)
+    if( ssl->transform_in->cipher_ctx_dec.cipher_info->mode ==
+                                                       POLARSSL_MODE_STREAM )
+    {
+        int ret;
+        size_t olen = 0;
+
+        padlen = 0;
+
+        if( ( ret = cipher_reset( &ssl->transform_in->cipher_ctx_dec ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_reset", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_set_iv( &ssl->transform_in->cipher_ctx_dec,
+                                   ssl->transform_in->iv_dec,
+                                   ssl->transform_in->ivlen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_iv", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_in->cipher_ctx_dec,
+                                   ssl->in_msg, ssl->in_msglen, ssl->in_msg,
+                                   &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_update", ret );
+            return( ret );
+        }
+
+        if( ssl->in_msglen != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect" ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+
+        if( ( ret = cipher_finish( &ssl->transform_in->cipher_ctx_dec,
+                                   ssl->in_msg + olen, &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_finish", ret );
+            return( ret );
+        }
+
+        if( 0 != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect" ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+    }
+    else
+#endif /* POLARSSL_ARC4_C || POLARSSL_CIPHER_NULL_CIPHER */
+#if defined(POLARSSL_GCM_C)
+    if( ssl->transform_in->cipher_ctx_dec.cipher_info->mode ==
+                                                       POLARSSL_MODE_GCM )
+    {
+        unsigned char *dec_msg;
+        unsigned char *dec_msg_result;
+        size_t dec_msglen, olen, totlen;
+        unsigned char add_data[13];
+        int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+
+        dec_msglen = ssl->in_msglen - ( ssl->transform_in->ivlen -
+                                        ssl->transform_in->fixed_ivlen );
+        dec_msglen -= 16;
+        dec_msg = ssl->in_msg;
+        dec_msg_result = ssl->in_msg;
+        ssl->in_msglen = dec_msglen;
+
+        memcpy( add_data, ssl->in_ctr, 8 );
+        add_data[8]  = ssl->in_msgtype;
+        add_data[9]  = ssl->major_ver;
+        add_data[10] = ssl->minor_ver;
+        add_data[11] = ( ssl->in_msglen >> 8 ) & 0xFF;
+        add_data[12] = ssl->in_msglen & 0xFF;
+
+        SSL_DEBUG_BUF( 4, "additional data used for AEAD",
+                       add_data, 13 );
+
+        memcpy( ssl->transform_in->iv_dec + ssl->transform_in->fixed_ivlen,
+                ssl->in_iv,
+                ssl->transform_in->ivlen - ssl->transform_in->fixed_ivlen );
+
+        SSL_DEBUG_BUF( 4, "IV used", ssl->transform_in->iv_dec,
+                                     ssl->transform_in->ivlen );
+        SSL_DEBUG_BUF( 4, "TAG used", dec_msg + dec_msglen, 16 );
+
+        /*
+         * Decrypt
+         */
+        if( ( ret = cipher_set_iv( &ssl->transform_in->cipher_ctx_dec,
+                                    ssl->transform_in->iv_dec,
+                                    ssl->transform_in->ivlen ) ) != 0 ||
+            ( ret = cipher_reset( &ssl->transform_in->cipher_ctx_dec ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        if( ( ret = cipher_update_ad( &ssl->transform_in->cipher_ctx_dec,
+                                      add_data, 13 ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_in->cipher_ctx_dec,
+                                   dec_msg, dec_msglen,
+                                   dec_msg_result, &olen ) ) != 0 )
+        {
+            return( ret );
+        }
+        totlen = olen;
+
+        if( ( ret = cipher_finish( &ssl->transform_in->cipher_ctx_dec,
+                                   dec_msg_result + olen, &olen ) ) != 0 )
+        {
+            return( ret );
+        }
+        totlen += olen;
+
+        if( totlen != dec_msglen )
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( -1 );
+        }
+
+        /*
+         * Authenticate
+         */
+        if( ( ret = cipher_check_tag( &ssl->transform_in->cipher_ctx_dec,
+                                      dec_msg + dec_msglen, 16 ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_check_tag", ret );
+            return( POLARSSL_ERR_SSL_INVALID_MAC );
+        }
+
+    }
+    else
+#endif /* POLARSSL_GCM_C */
+#if defined(POLARSSL_CIPHER_MODE_CBC) &&                                    \
+    ( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) )
+    if( ssl->transform_in->cipher_ctx_dec.cipher_info->mode ==
+                                                       POLARSSL_MODE_CBC )
+    {
+        /*
+         * Decrypt and check the padding
+         */
+        int ret;
+        unsigned char *dec_msg;
+        unsigned char *dec_msg_result;
+        size_t dec_msglen;
+        size_t minlen = 0;
+        size_t olen = 0;
+
+        /*
+         * Check immediate ciphertext sanity
+         */
+        if( ssl->in_msglen % ssl->transform_in->ivlen != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "msglen (%d) %% ivlen (%d) != 0",
+                           ssl->in_msglen, ssl->transform_in->ivlen ) );
+            return( POLARSSL_ERR_SSL_INVALID_MAC );
+        }
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_1) || defined(POLARSSL_SSL_PROTO_TLS1_2)
+        if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
+            minlen += ssl->transform_in->ivlen;
+#endif
+
+        if( ssl->in_msglen < minlen + ssl->transform_in->ivlen ||
+            ssl->in_msglen < minlen + ssl->transform_in->maclen + 1 )
+        {
+            SSL_DEBUG_MSG( 1, ( "msglen (%d) < max( ivlen(%d), maclen (%d) "
+                                "+ 1 ) ( + expl IV )", ssl->in_msglen,
+                                ssl->transform_in->ivlen,
+                                ssl->transform_in->maclen ) );
+            return( POLARSSL_ERR_SSL_INVALID_MAC );
+        }
+
+        dec_msglen = ssl->in_msglen;
+        dec_msg = ssl->in_msg;
+        dec_msg_result = ssl->in_msg;
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_1) || defined(POLARSSL_SSL_PROTO_TLS1_2)
+        /*
+         * Initialize for prepended IV for block cipher in TLS v1.1 and up
+         */
+        if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
+        {
+            dec_msglen -= ssl->transform_in->ivlen;
+            ssl->in_msglen -= ssl->transform_in->ivlen;
+
+            for( i = 0; i < ssl->transform_in->ivlen; i++ )
+                ssl->transform_in->iv_dec[i] = ssl->in_iv[i];
+        }
+#endif /* POLARSSL_SSL_PROTO_TLS1_1 || POLARSSL_SSL_PROTO_TLS1_2 */
+
+        if( ( ret = cipher_reset( &ssl->transform_in->cipher_ctx_dec ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_reset", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_set_iv( &ssl->transform_in->cipher_ctx_dec,
+                                   ssl->transform_in->iv_dec,
+                                   ssl->transform_in->ivlen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_set_iv", ret );
+            return( ret );
+        }
+
+        if( ( ret = cipher_update( &ssl->transform_in->cipher_ctx_dec,
+                                   dec_msg, dec_msglen, dec_msg_result,
+                                   &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_update", ret );
+            return( ret );
+        }
+
+        dec_msglen -= olen;
+        if( ( ret = cipher_finish( &ssl->transform_in->cipher_ctx_dec,
+                                   dec_msg_result + olen, &olen ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "cipher_finish", ret );
+            return( ret );
+        }
+
+        if( dec_msglen != olen )
+        {
+            SSL_DEBUG_MSG( 1, ( "total encrypted length incorrect" ) );
+            return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+        }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1)
+        if( ssl->minor_ver < SSL_MINOR_VERSION_2 )
+        {
+            /*
+             * Save IV in SSL3 and TLS1
+             */
+            memcpy( ssl->transform_in->iv_dec,
+                    ssl->transform_in->cipher_ctx_dec.iv,
+                    ssl->transform_in->ivlen );
+        }
+#endif
+
+        padlen = 1 + ssl->in_msg[ssl->in_msglen - 1];
+
+        if( ssl->in_msglen < ssl->transform_in->maclen + padlen )
+        {
+#if defined(POLARSSL_SSL_DEBUG_ALL)
+            SSL_DEBUG_MSG( 1, ( "msglen (%d) < maclen (%d) + padlen (%d)",
+                        ssl->in_msglen, ssl->transform_in->maclen, padlen ) );
+#endif
+            padlen = 0;
+            correct = 0;
+        }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+        if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+        {
+            if( padlen > ssl->transform_in->ivlen )
+            {
+#if defined(POLARSSL_SSL_DEBUG_ALL)
+                SSL_DEBUG_MSG( 1, ( "bad padding length: is %d, "
+                                    "should be no more than %d",
+                               padlen, ssl->transform_in->ivlen ) );
+#endif
+                correct = 0;
+            }
+        }
+        else
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_2)
+        if( ssl->minor_ver > SSL_MINOR_VERSION_0 )
+        {
+            /*
+             * TLSv1+: always check the padding up to the first failure
+             * and fake check up to 256 bytes of padding
+             */
+            size_t pad_count = 0, real_count = 1;
+            size_t padding_idx = ssl->in_msglen - padlen - 1;
+
+            /*
+             * Padding is guaranteed to be incorrect if:
+             *   1. padlen >= ssl->in_msglen
+             *
+             *   2. padding_idx >= SSL_MAX_CONTENT_LEN +
+             *                     ssl->transform_in->maclen
+             *
+             * In both cases we reset padding_idx to a safe value (0) to
+             * prevent out-of-buffer reads.
+             */
+            correct &= ( ssl->in_msglen >= padlen + 1 );
+            correct &= ( padding_idx < SSL_MAX_CONTENT_LEN +
+                                       ssl->transform_in->maclen );
+
+            padding_idx *= correct;
+
+            for( i = 1; i <= 256; i++ )
+            {
+                real_count &= ( i <= padlen );
+                pad_count += real_count *
+                             ( ssl->in_msg[padding_idx + i] == padlen - 1 );
+            }
+
+            correct &= ( pad_count == padlen ); /* Only 1 on correct padding */
+
+#if defined(POLARSSL_SSL_DEBUG_ALL)
+            if( padlen > 0 && correct == 0)
+                SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) );
+#endif
+            padlen &= correct * 0x1FF;
+        }
+        else
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 || \
+          POLARSSL_SSL_PROTO_TLS1_2 */
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+        }
+    }
+    else
+#endif /* POLARSSL_CIPHER_MODE_CBC &&
+          ( POLARSSL_AES_C || POLARSSL_CAMELLIA_C ) */
+    {
+        SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+    }
+
+    SSL_DEBUG_BUF( 4, "raw buffer after decryption",
+                   ssl->in_msg, ssl->in_msglen );
+
+    /*
+     * Always compute the MAC (RFC4346, CBCTIME), except for GCM of course
+     */
+#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) ||     \
+    ( defined(POLARSSL_CIPHER_MODE_CBC) &&                                  \
+      ( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
+    if( ssl->transform_in->cipher_ctx_dec.cipher_info->mode !=
+                                                        POLARSSL_MODE_GCM )
+    {
+        unsigned char tmp[POLARSSL_SSL_MAX_MAC_SIZE];
+
+        ssl->in_msglen -= ( ssl->transform_in->maclen + padlen );
+
+        ssl->in_hdr[3] = (unsigned char)( ssl->in_msglen >> 8 );
+        ssl->in_hdr[4] = (unsigned char)( ssl->in_msglen      );
+
+        memcpy( tmp, ssl->in_msg + ssl->in_msglen, ssl->transform_in->maclen );
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+        if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+        {
+            ssl_mac( &ssl->transform_in->md_ctx_dec,
+                      ssl->transform_in->mac_dec,
+                      ssl->in_msg, ssl->in_msglen,
+                      ssl->in_ctr, ssl->in_msgtype );
+        }
+        else
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+        defined(POLARSSL_SSL_PROTO_TLS1_2)
+        if( ssl->minor_ver > SSL_MINOR_VERSION_0 )
+        {
+            /*
+             * Process MAC and always update for padlen afterwards to make
+             * total time independent of padlen
+             *
+             * extra_run compensates MAC check for padlen
+             *
+             * Known timing attacks:
+             *  - Lucky Thirteen (http://www.isg.rhul.ac.uk/tls/TLStiming.pdf)
+             *
+             * We use ( ( Lx + 8 ) / 64 ) to handle 'negative Lx' values
+             * correctly. (We round down instead of up, so -56 is the correct
+             * value for our calculations instead of -55)
+             */
+            size_t j, extra_run = 0;
+            extra_run = ( 13 + ssl->in_msglen + padlen + 8 ) / 64 -
+                        ( 13 + ssl->in_msglen          + 8 ) / 64;
+
+            extra_run &= correct * 0xFF;
+
+            md_hmac_update( &ssl->transform_in->md_ctx_dec, ssl->in_ctr, 13 );
+            md_hmac_update( &ssl->transform_in->md_ctx_dec, ssl->in_msg,
+                             ssl->in_msglen );
+            md_hmac_finish( &ssl->transform_in->md_ctx_dec,
+                             ssl->in_msg + ssl->in_msglen );
+            for( j = 0; j < extra_run; j++ )
+                md_process( &ssl->transform_in->md_ctx_dec, ssl->in_msg );
+
+            md_hmac_reset( &ssl->transform_in->md_ctx_dec );
+        }
+        else
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 || \
+              POLARSSL_SSL_PROTO_TLS1_2 */
+        {
+            SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+        }
+
+        SSL_DEBUG_BUF( 4, "message  mac", tmp, ssl->transform_in->maclen );
+        SSL_DEBUG_BUF( 4, "computed mac", ssl->in_msg + ssl->in_msglen,
+                       ssl->transform_in->maclen );
+
+        if( safer_memcmp( tmp, ssl->in_msg + ssl->in_msglen,
+                         ssl->transform_in->maclen ) != 0 )
+        {
+#if defined(POLARSSL_SSL_DEBUG_ALL)
+            SSL_DEBUG_MSG( 1, ( "message mac does not match" ) );
+#endif
+            correct = 0;
+        }
+
+        /*
+         * Finally check the correct flag
+         */
+        if( correct == 0 )
+            return( POLARSSL_ERR_SSL_INVALID_MAC );
+    }
+#endif /* GCM not the only option */
+
+    if( ssl->in_msglen == 0 )
+    {
+        ssl->nb_zero++;
+
+        /*
+         * Three or more empty messages may be a DoS attack
+         * (excessive CPU consumption).
+         */
+        if( ssl->nb_zero > 3 )
+        {
+            SSL_DEBUG_MSG( 1, ( "received four consecutive empty "
+                                "messages, possible DoS attack" ) );
+            return( POLARSSL_ERR_SSL_INVALID_MAC );
+        }
+    }
+    else
+        ssl->nb_zero = 0;
+
+    for( i = 8; i > 0; i-- )
+        if( ++ssl->in_ctr[i - 1] != 0 )
+            break;
+
+    /* The loops goes to its end iff the counter is wrapping */
+    if( i == 0 )
+    {
+        SSL_DEBUG_MSG( 1, ( "incoming message counter would wrap" ) );
+        return( POLARSSL_ERR_SSL_COUNTER_WRAPPING );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= decrypt buf" ) );
+
+    return( 0 );
+}
+
+#if defined(POLARSSL_ZLIB_SUPPORT)
+/*
+ * Compression/decompression functions
+ */
+static int ssl_compress_buf( ssl_context *ssl )
+{
+    int ret;
+    unsigned char *msg_post = ssl->out_msg;
+    size_t len_pre = ssl->out_msglen;
+    unsigned char *msg_pre = ssl->compress_buf;
+
+    SSL_DEBUG_MSG( 2, ( "=> compress buf" ) );
+
+    if( len_pre == 0 )
+        return( 0 );
+
+    memcpy( msg_pre, ssl->out_msg, len_pre );
+
+    SSL_DEBUG_MSG( 3, ( "before compression: msglen = %d, ",
+                   ssl->out_msglen ) );
+
+    SSL_DEBUG_BUF( 4, "before compression: output payload",
+                   ssl->out_msg, ssl->out_msglen );
+
+    ssl->transform_out->ctx_deflate.next_in = msg_pre;
+    ssl->transform_out->ctx_deflate.avail_in = len_pre;
+    ssl->transform_out->ctx_deflate.next_out = msg_post;
+    ssl->transform_out->ctx_deflate.avail_out = SSL_BUFFER_LEN;
+
+    ret = deflate( &ssl->transform_out->ctx_deflate, Z_SYNC_FLUSH );
+    if( ret != Z_OK )
+    {
+        SSL_DEBUG_MSG( 1, ( "failed to perform compression (%d)", ret ) );
+        return( POLARSSL_ERR_SSL_COMPRESSION_FAILED );
+    }
+
+    ssl->out_msglen = SSL_BUFFER_LEN -
+                      ssl->transform_out->ctx_deflate.avail_out;
+
+    SSL_DEBUG_MSG( 3, ( "after compression: msglen = %d, ",
+                   ssl->out_msglen ) );
+
+    SSL_DEBUG_BUF( 4, "after compression: output payload",
+                   ssl->out_msg, ssl->out_msglen );
+
+    SSL_DEBUG_MSG( 2, ( "<= compress buf" ) );
+
+    return( 0 );
+}
+
+static int ssl_decompress_buf( ssl_context *ssl )
+{
+    int ret;
+    unsigned char *msg_post = ssl->in_msg;
+    size_t len_pre = ssl->in_msglen;
+    unsigned char *msg_pre = ssl->compress_buf;
+
+    SSL_DEBUG_MSG( 2, ( "=> decompress buf" ) );
+
+    if( len_pre == 0 )
+        return( 0 );
+
+    memcpy( msg_pre, ssl->in_msg, len_pre );
+
+    SSL_DEBUG_MSG( 3, ( "before decompression: msglen = %d, ",
+                   ssl->in_msglen ) );
+
+    SSL_DEBUG_BUF( 4, "before decompression: input payload",
+                   ssl->in_msg, ssl->in_msglen );
+
+    ssl->transform_in->ctx_inflate.next_in = msg_pre;
+    ssl->transform_in->ctx_inflate.avail_in = len_pre;
+    ssl->transform_in->ctx_inflate.next_out = msg_post;
+    ssl->transform_in->ctx_inflate.avail_out = SSL_MAX_CONTENT_LEN;
+
+    ret = inflate( &ssl->transform_in->ctx_inflate, Z_SYNC_FLUSH );
+    if( ret != Z_OK )
+    {
+        SSL_DEBUG_MSG( 1, ( "failed to perform decompression (%d)", ret ) );
+        return( POLARSSL_ERR_SSL_COMPRESSION_FAILED );
+    }
+
+    ssl->in_msglen = SSL_MAX_CONTENT_LEN -
+                     ssl->transform_in->ctx_inflate.avail_out;
+
+    SSL_DEBUG_MSG( 3, ( "after decompression: msglen = %d, ",
+                   ssl->in_msglen ) );
+
+    SSL_DEBUG_BUF( 4, "after decompression: input payload",
+                   ssl->in_msg, ssl->in_msglen );
+
+    SSL_DEBUG_MSG( 2, ( "<= decompress buf" ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_ZLIB_SUPPORT */
+
+/*
+ * Fill the input message buffer
+ */
+int ssl_fetch_input( ssl_context *ssl, size_t nb_want )
+{
+    int ret;
+    size_t len;
+
+    SSL_DEBUG_MSG( 2, ( "=> fetch input" ) );
+
+    if( nb_want > SSL_BUFFER_LEN - 8 )
+    {
+        SSL_DEBUG_MSG( 1, ( "requesting more data than fits" ) );
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    while( ssl->in_left < nb_want )
+    {
+        len = nb_want - ssl->in_left;
+        ret = ssl->f_recv( ssl->p_recv, ssl->in_hdr + ssl->in_left, len );
+
+        SSL_DEBUG_MSG( 2, ( "in_left: %d, nb_want: %d",
+                       ssl->in_left, nb_want ) );
+        SSL_DEBUG_RET( 2, "ssl->f_recv", ret );
+
+        if( ret == 0 )
+            return( POLARSSL_ERR_SSL_CONN_EOF );
+
+        if( ret < 0 )
+            return( ret );
+
+        ssl->in_left += ret;
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= fetch input" ) );
+
+    return( 0 );
+}
+
+/*
+ * Flush any data not yet written
+ */
+int ssl_flush_output( ssl_context *ssl )
+{
+    int ret;
+    unsigned char *buf;
+
+    SSL_DEBUG_MSG( 2, ( "=> flush output" ) );
+
+    while( ssl->out_left > 0 )
+    {
+        SSL_DEBUG_MSG( 2, ( "message length: %d, out_left: %d",
+                       5 + ssl->out_msglen, ssl->out_left ) );
+
+        buf = ssl->out_hdr + 5 + ssl->out_msglen - ssl->out_left;
+        ret = ssl->f_send( ssl->p_send, buf, ssl->out_left );
+
+        SSL_DEBUG_RET( 2, "ssl->f_send", ret );
+
+        if( ret <= 0 )
+            return( ret );
+
+        ssl->out_left -= ret;
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= flush output" ) );
+
+    return( 0 );
+}
+
+/*
+ * Record layer functions
+ */
+int ssl_write_record( ssl_context *ssl )
+{
+    int ret, done = 0;
+    size_t len = ssl->out_msglen;
+
+    SSL_DEBUG_MSG( 2, ( "=> write record" ) );
+
+    if( ssl->out_msgtype == SSL_MSG_HANDSHAKE )
+    {
+        ssl->out_msg[1] = (unsigned char)( ( len - 4 ) >> 16 );
+        ssl->out_msg[2] = (unsigned char)( ( len - 4 ) >>  8 );
+        ssl->out_msg[3] = (unsigned char)( ( len - 4 )       );
+
+        if( ssl->out_msg[0] != SSL_HS_HELLO_REQUEST )
+            ssl->handshake->update_checksum( ssl, ssl->out_msg, len );
+    }
+
+#if defined(POLARSSL_ZLIB_SUPPORT)
+    if( ssl->transform_out != NULL &&
+        ssl->session_out->compression == SSL_COMPRESS_DEFLATE )
+    {
+        if( ( ret = ssl_compress_buf( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_compress_buf", ret );
+            return( ret );
+        }
+
+        len = ssl->out_msglen;
+    }
+#endif /*POLARSSL_ZLIB_SUPPORT */
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_write != NULL)
+    {
+        SSL_DEBUG_MSG( 2, ( "going for ssl_hw_record_write()" ) );
+
+        ret = ssl_hw_record_write( ssl );
+        if( ret != 0 && ret != POLARSSL_ERR_SSL_HW_ACCEL_FALLTHROUGH )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_write", ret );
+            return POLARSSL_ERR_SSL_HW_ACCEL_FAILED;
+        }
+
+        if( ret == 0 )
+            done = 1;
+    }
+#endif /* POLARSSL_SSL_HW_RECORD_ACCEL */
+    if( !done )
+    {
+        ssl->out_hdr[0] = (unsigned char) ssl->out_msgtype;
+        ssl->out_hdr[1] = (unsigned char) ssl->major_ver;
+        ssl->out_hdr[2] = (unsigned char) ssl->minor_ver;
+        ssl->out_hdr[3] = (unsigned char)( len >> 8 );
+        ssl->out_hdr[4] = (unsigned char)( len      );
+
+        if( ssl->transform_out != NULL )
+        {
+            if( ( ret = ssl_encrypt_buf( ssl ) ) != 0 )
+            {
+                SSL_DEBUG_RET( 1, "ssl_encrypt_buf", ret );
+                return( ret );
+            }
+
+            len = ssl->out_msglen;
+            ssl->out_hdr[3] = (unsigned char)( len >> 8 );
+            ssl->out_hdr[4] = (unsigned char)( len      );
+        }
+
+        ssl->out_left = 5 + ssl->out_msglen;
+
+        SSL_DEBUG_MSG( 3, ( "output record: msgtype = %d, "
+                            "version = [%d:%d], msglen = %d",
+                       ssl->out_hdr[0], ssl->out_hdr[1], ssl->out_hdr[2],
+                     ( ssl->out_hdr[3] << 8 ) | ssl->out_hdr[4] ) );
+
+        SSL_DEBUG_BUF( 4, "output record sent to network",
+                       ssl->out_hdr, 5 + ssl->out_msglen );
+    }
+
+    if( ( ret = ssl_flush_output( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_flush_output", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write record" ) );
+
+    return( 0 );
+}
+
+int ssl_read_record( ssl_context *ssl )
+{
+    int ret, done = 0;
+
+    SSL_DEBUG_MSG( 2, ( "=> read record" ) );
+
+    SSL_DEBUG_BUF( 4, "input record from network",
+                   ssl->in_hdr, 5 + ssl->in_msglen );
+
+    if( ssl->in_hslen != 0 &&
+        ssl->in_hslen < ssl->in_msglen )
+    {
+        /*
+         * Get next Handshake message in the current record
+         */
+        ssl->in_msglen -= ssl->in_hslen;
+
+        memmove( ssl->in_msg, ssl->in_msg + ssl->in_hslen,
+                 ssl->in_msglen );
+
+        ssl->in_hslen  = 4;
+        ssl->in_hslen += ( ssl->in_msg[2] << 8 ) | ssl->in_msg[3];
+
+        SSL_DEBUG_MSG( 3, ( "handshake message: msglen ="
+                            " %d, type = %d, hslen = %d",
+                       ssl->in_msglen, ssl->in_msg[0], ssl->in_hslen ) );
+
+        if( ssl->in_msglen < 4 || ssl->in_msg[1] != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad handshake length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+
+        if( ssl->in_msglen < ssl->in_hslen )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad handshake length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+
+        if( ssl->state != SSL_HANDSHAKE_OVER )
+            ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen );
+
+        return( 0 );
+    }
+
+    ssl->in_hslen = 0;
+
+    /*
+     * Read the record header and validate it
+     */
+    if( ( ret = ssl_fetch_input( ssl, 5 ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
+        return( ret );
+    }
+
+    ssl->in_msgtype =  ssl->in_hdr[0];
+    ssl->in_msglen = ( ssl->in_hdr[3] << 8 ) | ssl->in_hdr[4];
+
+    SSL_DEBUG_MSG( 3, ( "input record: msgtype = %d, "
+                        "version = [%d:%d], msglen = %d",
+                     ssl->in_hdr[0], ssl->in_hdr[1], ssl->in_hdr[2],
+                   ( ssl->in_hdr[3] << 8 ) | ssl->in_hdr[4] ) );
+
+    if( ssl->in_hdr[1] != ssl->major_ver )
+    {
+        SSL_DEBUG_MSG( 1, ( "major version mismatch" ) );
+        return( POLARSSL_ERR_SSL_INVALID_RECORD );
+    }
+
+    if( ssl->in_hdr[2] > ssl->max_minor_ver )
+    {
+        SSL_DEBUG_MSG( 1, ( "minor version mismatch" ) );
+        return( POLARSSL_ERR_SSL_INVALID_RECORD );
+    }
+
+    /* Sanity check (outer boundaries) */
+    if( ssl->in_msglen < 1 || ssl->in_msglen > SSL_BUFFER_LEN - 13 )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+        return( POLARSSL_ERR_SSL_INVALID_RECORD );
+    }
+
+    /*
+     * Make sure the message length is acceptable for the current transform
+     * and protocol version.
+     */
+    if( ssl->transform_in == NULL )
+    {
+        if( ssl->in_msglen > SSL_MAX_CONTENT_LEN )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+    }
+    else
+    {
+        if( ssl->in_msglen < ssl->transform_in->minlen )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+        if( ssl->minor_ver == SSL_MINOR_VERSION_0 &&
+            ssl->in_msglen > ssl->transform_in->minlen + SSL_MAX_CONTENT_LEN )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+#endif
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_2)
+        /*
+         * TLS encrypted messages can have up to 256 bytes of padding
+         */
+        if( ssl->minor_ver >= SSL_MINOR_VERSION_1 &&
+            ssl->in_msglen > ssl->transform_in->minlen +
+                             SSL_MAX_CONTENT_LEN + 256 )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+#endif
+    }
+
+    /*
+     * Read and optionally decrypt the message contents
+     */
+    if( ( ret = ssl_fetch_input( ssl, 5 + ssl->in_msglen ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_BUF( 4, "input record from network",
+                   ssl->in_hdr, 5 + ssl->in_msglen );
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_read != NULL)
+    {
+        SSL_DEBUG_MSG( 2, ( "going for ssl_hw_record_read()" ) );
+
+        ret = ssl_hw_record_read( ssl );
+        if( ret != 0 && ret != POLARSSL_ERR_SSL_HW_ACCEL_FALLTHROUGH )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_read", ret );
+            return POLARSSL_ERR_SSL_HW_ACCEL_FAILED;
+        }
+
+        if( ret == 0 )
+            done = 1;
+    }
+#endif /* POLARSSL_SSL_HW_RECORD_ACCEL */
+    if( !done && ssl->transform_in != NULL )
+    {
+        if( ( ret = ssl_decrypt_buf( ssl ) ) != 0 )
+        {
+#if defined(POLARSSL_SSL_ALERT_MESSAGES)
+            if( ret == POLARSSL_ERR_SSL_INVALID_MAC )
+            {
+                ssl_send_alert_message( ssl,
+                                        SSL_ALERT_LEVEL_FATAL,
+                                        SSL_ALERT_MSG_BAD_RECORD_MAC );
+            }
+#endif
+            SSL_DEBUG_RET( 1, "ssl_decrypt_buf", ret );
+            return( ret );
+        }
+
+        SSL_DEBUG_BUF( 4, "input payload after decrypt",
+                       ssl->in_msg, ssl->in_msglen );
+
+        if( ssl->in_msglen > SSL_MAX_CONTENT_LEN )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad message length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+    }
+
+#if defined(POLARSSL_ZLIB_SUPPORT)
+    if( ssl->transform_in != NULL &&
+        ssl->session_in->compression == SSL_COMPRESS_DEFLATE )
+    {
+        if( ( ret = ssl_decompress_buf( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_decompress_buf", ret );
+            return( ret );
+        }
+
+        ssl->in_hdr[3] = (unsigned char)( ssl->in_msglen >> 8 );
+        ssl->in_hdr[4] = (unsigned char)( ssl->in_msglen      );
+    }
+#endif /* POLARSSL_ZLIB_SUPPORT */
+
+    if( ssl->in_msgtype != SSL_MSG_HANDSHAKE &&
+        ssl->in_msgtype != SSL_MSG_ALERT &&
+        ssl->in_msgtype != SSL_MSG_CHANGE_CIPHER_SPEC &&
+        ssl->in_msgtype != SSL_MSG_APPLICATION_DATA )
+    {
+        SSL_DEBUG_MSG( 1, ( "unknown record type" ) );
+
+        if( ( ret = ssl_send_alert_message( ssl,
+                        SSL_ALERT_LEVEL_FATAL,
+                        SSL_ALERT_MSG_UNEXPECTED_MESSAGE ) ) != 0 )
+        {
+            return( ret );
+        }
+
+        return( POLARSSL_ERR_SSL_INVALID_RECORD );
+    }
+
+    if( ssl->in_msgtype == SSL_MSG_HANDSHAKE )
+    {
+        ssl->in_hslen  = 4;
+        ssl->in_hslen += ( ssl->in_msg[2] << 8 ) | ssl->in_msg[3];
+
+        SSL_DEBUG_MSG( 3, ( "handshake message: msglen ="
+                            " %d, type = %d, hslen = %d",
+                       ssl->in_msglen, ssl->in_msg[0], ssl->in_hslen ) );
+
+        /*
+         * Additional checks to validate the handshake header
+         */
+        if( ssl->in_msglen < 4 || ssl->in_msg[1] != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad handshake length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+
+        if( ssl->in_msglen < ssl->in_hslen )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad handshake length" ) );
+            return( POLARSSL_ERR_SSL_INVALID_RECORD );
+        }
+
+        if( ssl->state != SSL_HANDSHAKE_OVER )
+            ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen );
+    }
+
+    if( ssl->in_msgtype == SSL_MSG_ALERT )
+    {
+        SSL_DEBUG_MSG( 2, ( "got an alert message, type: [%d:%d]",
+                       ssl->in_msg[0], ssl->in_msg[1] ) );
+
+        /*
+         * Ignore non-fatal alerts, except close_notify
+         */
+        if( ssl->in_msg[0] == SSL_ALERT_LEVEL_FATAL )
+        {
+            SSL_DEBUG_MSG( 1, ( "is a fatal alert message (msg %d)",
+                           ssl->in_msg[1] ) );
+            /**
+             * Subtract from error code as ssl->in_msg[1] is 7-bit positive
+             * error identifier.
+             */
+            return( POLARSSL_ERR_SSL_FATAL_ALERT_MESSAGE );
+        }
+
+        if( ssl->in_msg[0] == SSL_ALERT_LEVEL_WARNING &&
+            ssl->in_msg[1] == SSL_ALERT_MSG_CLOSE_NOTIFY )
+        {
+            SSL_DEBUG_MSG( 2, ( "is a close notify message" ) );
+            return( POLARSSL_ERR_SSL_PEER_CLOSE_NOTIFY );
+        }
+    }
+
+    ssl->in_left = 0;
+
+    SSL_DEBUG_MSG( 2, ( "<= read record" ) );
+
+    return( 0 );
+}
+
+int ssl_send_fatal_handshake_failure( ssl_context *ssl )
+{
+    int ret;
+
+    if( ( ret = ssl_send_alert_message( ssl,
+                    SSL_ALERT_LEVEL_FATAL,
+                    SSL_ALERT_MSG_HANDSHAKE_FAILURE ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+
+int ssl_send_alert_message( ssl_context *ssl,
+                            unsigned char level,
+                            unsigned char message )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> send alert message" ) );
+
+    ssl->out_msgtype = SSL_MSG_ALERT;
+    ssl->out_msglen = 2;
+    ssl->out_msg[0] = level;
+    ssl->out_msg[1] = message;
+
+    if( ( ret = ssl_write_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= send alert message" ) );
+
+    return( 0 );
+}
+
+/*
+ * Handshake functions
+ */
+#if !defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED)         && \
+    !defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)     && \
+    !defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED)     && \
+    !defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED)   && \
+    !defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) && \
+    !defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED)    && \
+    !defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+int ssl_write_certificate( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+    const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
+
+    SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );
+
+    if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
+    {
+        SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
+        ssl->state++;
+        return( 0 );
+    }
+
+    SSL_DEBUG_MSG( 1, ( "should not happen" ) );
+    return( ret );
+}
+
+int ssl_parse_certificate( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+    const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
+
+    SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
+
+    if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
+    {
+        SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
+        ssl->state++;
+        return( 0 );
+    }
+
+    SSL_DEBUG_MSG( 1, ( "should not happen" ) );
+    return( ret );
+}
+#else
+int ssl_write_certificate( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+    size_t i, n;
+    const x509_crt *crt;
+    const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
+
+    SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );
+
+    if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
+    {
+        SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
+        ssl->state++;
+        return( 0 );
+    }
+
+    if( ssl->endpoint == SSL_IS_CLIENT )
+    {
+        if( ssl->client_auth == 0 )
+        {
+            SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
+            ssl->state++;
+            return( 0 );
+        }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+        /*
+         * If using SSLv3 and got no cert, send an Alert message
+         * (otherwise an empty Certificate message will be sent).
+         */
+        if( ssl_own_cert( ssl )  == NULL &&
+            ssl->minor_ver == SSL_MINOR_VERSION_0 )
+        {
+            ssl->out_msglen  = 2;
+            ssl->out_msgtype = SSL_MSG_ALERT;
+            ssl->out_msg[0]  = SSL_ALERT_LEVEL_WARNING;
+            ssl->out_msg[1]  = SSL_ALERT_MSG_NO_CERT;
+
+            SSL_DEBUG_MSG( 2, ( "got no certificate to send" ) );
+            goto write_msg;
+        }
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+    }
+    else /* SSL_IS_SERVER */
+    {
+        if( ssl_own_cert( ssl ) == NULL )
+        {
+            SSL_DEBUG_MSG( 1, ( "got no certificate to send" ) );
+            return( POLARSSL_ERR_SSL_CERTIFICATE_REQUIRED );
+        }
+    }
+
+    SSL_DEBUG_CRT( 3, "own certificate", ssl_own_cert( ssl ) );
+
+    /*
+     *     0  .  0    handshake type
+     *     1  .  3    handshake length
+     *     4  .  6    length of all certs
+     *     7  .  9    length of cert. 1
+     *    10  . n-1   peer certificate
+     *     n  . n+2   length of cert. 2
+     *    n+3 . ...   upper level cert, etc.
+     */
+    i = 7;
+    crt = ssl_own_cert( ssl );
+
+    while( crt != NULL )
+    {
+        n = crt->raw.len;
+        if( n > SSL_MAX_CONTENT_LEN - 3 - i )
+        {
+            SSL_DEBUG_MSG( 1, ( "certificate too large, %d > %d",
+                           i + 3 + n, SSL_MAX_CONTENT_LEN ) );
+            return( POLARSSL_ERR_SSL_CERTIFICATE_TOO_LARGE );
+        }
+
+        ssl->out_msg[i    ] = (unsigned char)( n >> 16 );
+        ssl->out_msg[i + 1] = (unsigned char)( n >>  8 );
+        ssl->out_msg[i + 2] = (unsigned char)( n       );
+
+        i += 3; memcpy( ssl->out_msg + i, crt->raw.p, n );
+        i += n; crt = crt->next;
+    }
+
+    ssl->out_msg[4]  = (unsigned char)( ( i - 7 ) >> 16 );
+    ssl->out_msg[5]  = (unsigned char)( ( i - 7 ) >>  8 );
+    ssl->out_msg[6]  = (unsigned char)( ( i - 7 )       );
+
+    ssl->out_msglen  = i;
+    ssl->out_msgtype = SSL_MSG_HANDSHAKE;
+    ssl->out_msg[0]  = SSL_HS_CERTIFICATE;
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+write_msg:
+#endif
+
+    ssl->state++;
+
+    if( ( ret = ssl_write_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write certificate" ) );
+
+    return( ret );
+}
+
+int ssl_parse_certificate( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+    size_t i, n;
+    const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
+
+    SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
+
+    if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ||
+        ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK )
+    {
+        SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
+        ssl->state++;
+        return( 0 );
+    }
+
+    if( ssl->endpoint == SSL_IS_SERVER &&
+        ( ssl->authmode == SSL_VERIFY_NONE ||
+          ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ) )
+    {
+        ssl->session_negotiate->verify_result = BADCERT_SKIP_VERIFY;
+        SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
+        ssl->state++;
+        return( 0 );
+    }
+
+    if( ( ret = ssl_read_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_read_record", ret );
+        return( ret );
+    }
+
+    ssl->state++;
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+    /*
+     * Check if the client sent an empty certificate
+     */
+    if( ssl->endpoint  == SSL_IS_SERVER &&
+        ssl->minor_ver == SSL_MINOR_VERSION_0 )
+    {
+        if( ssl->in_msglen  == 2                        &&
+            ssl->in_msgtype == SSL_MSG_ALERT            &&
+            ssl->in_msg[0]  == SSL_ALERT_LEVEL_WARNING  &&
+            ssl->in_msg[1]  == SSL_ALERT_MSG_NO_CERT )
+        {
+            SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
+
+            ssl->session_negotiate->verify_result = BADCERT_MISSING;
+            if( ssl->authmode == SSL_VERIFY_OPTIONAL )
+                return( 0 );
+            else
+                return( POLARSSL_ERR_SSL_NO_CLIENT_CERTIFICATE );
+        }
+    }
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_2)
+    if( ssl->endpoint  == SSL_IS_SERVER &&
+        ssl->minor_ver != SSL_MINOR_VERSION_0 )
+    {
+        if( ssl->in_hslen   == 7                    &&
+            ssl->in_msgtype == SSL_MSG_HANDSHAKE    &&
+            ssl->in_msg[0]  == SSL_HS_CERTIFICATE   &&
+            memcmp( ssl->in_msg + 4, "\0\0\0", 3 ) == 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
+
+            ssl->session_negotiate->verify_result = BADCERT_MISSING;
+            if( ssl->authmode == SSL_VERIFY_REQUIRED )
+                return( POLARSSL_ERR_SSL_NO_CLIENT_CERTIFICATE );
+            else
+                return( 0 );
+        }
+    }
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 || \
+          POLARSSL_SSL_PROTO_TLS1_2 */
+
+    if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+    }
+
+    if( ssl->in_msg[0] != SSL_HS_CERTIFICATE || ssl->in_hslen < 10 )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+    }
+
+    /*
+     * Same message structure as in ssl_write_certificate()
+     */
+    n = ( ssl->in_msg[5] << 8 ) | ssl->in_msg[6];
+
+    if( ssl->in_msg[4] != 0 || ssl->in_hslen != 7 + n )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+        return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+    }
+
+    /* In case we tried to reuse a session but it failed */
+    if( ssl->session_negotiate->peer_cert != NULL )
+    {
+        x509_crt_free( ssl->session_negotiate->peer_cert );
+        polarssl_free( ssl->session_negotiate->peer_cert );
+    }
+
+    if( ( ssl->session_negotiate->peer_cert = (x509_crt *) polarssl_malloc(
+                    sizeof( x509_crt ) ) ) == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "malloc(%d bytes) failed",
+                       sizeof( x509_crt ) ) );
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    }
+
+    x509_crt_init( ssl->session_negotiate->peer_cert );
+
+    i = 7;
+
+    while( i < ssl->in_hslen )
+    {
+        if( ssl->in_msg[i] != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+            return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+        }
+
+        n = ( (unsigned int) ssl->in_msg[i + 1] << 8 )
+            | (unsigned int) ssl->in_msg[i + 2];
+        i += 3;
+
+        if( n < 128 || i + n > ssl->in_hslen )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
+            return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+        }
+
+        ret = x509_crt_parse_der( ssl->session_negotiate->peer_cert,
+                                  ssl->in_msg + i, n );
+        if( ret != 0 )
+        {
+            SSL_DEBUG_RET( 1, " x509_crt_parse_der", ret );
+            return( ret );
+        }
+
+        i += n;
+    }
+
+    SSL_DEBUG_CRT( 3, "peer certificate", ssl->session_negotiate->peer_cert );
+
+    /*
+     * On client, make sure the server cert doesn't change during renego to
+     * avoid "triple handshake" attack: https://secure-resumption.com/
+     */
+    if( ssl->endpoint == SSL_IS_CLIENT &&
+        ssl->renegotiation == SSL_RENEGOTIATION )
+    {
+        if( ssl->session->peer_cert == NULL )
+        {
+            SSL_DEBUG_MSG( 1, ( "new server cert during renegotiation" ) );
+            return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+        }
+
+        if( ssl->session->peer_cert->raw.len !=
+            ssl->session_negotiate->peer_cert->raw.len ||
+            memcmp( ssl->session->peer_cert->raw.p,
+                    ssl->session_negotiate->peer_cert->raw.p,
+                    ssl->session->peer_cert->raw.len ) != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "server cert changed during renegotiation" ) );
+            return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
+        }
+    }
+
+    if( ssl->authmode != SSL_VERIFY_NONE )
+    {
+        if( ssl->ca_chain == NULL )
+        {
+            SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
+            return( POLARSSL_ERR_SSL_CA_CHAIN_REQUIRED );
+        }
+
+        /*
+         * Main check: verify certificate
+         */
+        ret = x509_crt_verify( ssl->session_negotiate->peer_cert,
+                               ssl->ca_chain, ssl->ca_crl, ssl->peer_cn,
+                              &ssl->session_negotiate->verify_result,
+                               ssl->f_vrfy, ssl->p_vrfy );
+
+        if( ret != 0 )
+        {
+            SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
+        }
+
+        /*
+         * Secondary checks: always done, but change 'ret' only if it was 0
+         */
+
+#if defined(POLARSSL_SSL_SET_CURVES)
+        {
+            pk_context *pk = &ssl->session_negotiate->peer_cert->pk;
+
+            /* If certificate uses an EC key, make sure the curve is OK */
+            if( pk_can_do( pk, POLARSSL_PK_ECKEY ) &&
+                ! ssl_curve_is_acceptable( ssl, pk_ec( *pk )->grp.id ) )
+            {
+                SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
+                if( ret == 0 )
+                    ret = POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE;
+            }
+        }
+#endif /* POLARSSL_SSL_SET_CURVES */
+
+        if( ssl_check_cert_usage( ssl->session_negotiate->peer_cert,
+                                  ciphersuite_info,
+                                  ! ssl->endpoint ) != 0 )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad certificate (usage extensions)" ) );
+            if( ret == 0 )
+                ret = POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE;
+        }
+
+        if( ssl->authmode != SSL_VERIFY_REQUIRED )
+            ret = 0;
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );
+
+    return( ret );
+}
+#endif /* !POLARSSL_KEY_EXCHANGE_RSA_ENABLED
+          !POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED
+          !POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED
+          !POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED
+          !POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
+          !POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED
+          !POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
+
+int ssl_write_change_cipher_spec( ssl_context *ssl )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> write change cipher spec" ) );
+
+    ssl->out_msgtype = SSL_MSG_CHANGE_CIPHER_SPEC;
+    ssl->out_msglen  = 1;
+    ssl->out_msg[0]  = 1;
+
+    ssl->state++;
+
+    if( ( ret = ssl_write_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write change cipher spec" ) );
+
+    return( 0 );
+}
+
+int ssl_parse_change_cipher_spec( ssl_context *ssl )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) );
+
+    if( ( ret = ssl_read_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_read_record", ret );
+        return( ret );
+    }
+
+    if( ssl->in_msgtype != SSL_MSG_CHANGE_CIPHER_SPEC )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
+        return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+    }
+
+    if( ssl->in_msglen != 1 || ssl->in_msg[0] != 1 )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
+        return( POLARSSL_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC );
+    }
+
+    ssl->state++;
+
+    SSL_DEBUG_MSG( 2, ( "<= parse change cipher spec" ) );
+
+    return( 0 );
+}
+
+void ssl_optimize_checksum( ssl_context *ssl,
+                            const ssl_ciphersuite_t *ciphersuite_info )
+{
+    ((void) ciphersuite_info);
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_1)
+    if( ssl->minor_ver < SSL_MINOR_VERSION_3 )
+        ssl->handshake->update_checksum = ssl_update_checksum_md5sha1;
+    else
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA512_C)
+    if( ciphersuite_info->mac == POLARSSL_MD_SHA384 )
+        ssl->handshake->update_checksum = ssl_update_checksum_sha384;
+    else
+#endif
+#if defined(POLARSSL_SHA256_C)
+    if( ciphersuite_info->mac != POLARSSL_MD_SHA384 )
+        ssl->handshake->update_checksum = ssl_update_checksum_sha256;
+    else
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+        /* Should never happen */
+        return;
+}
+
+static void ssl_update_checksum_start( ssl_context *ssl,
+                                       const unsigned char *buf, size_t len )
+{
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_1)
+     md5_update( &ssl->handshake->fin_md5 , buf, len );
+    sha1_update( &ssl->handshake->fin_sha1, buf, len );
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+    sha256_update( &ssl->handshake->fin_sha256, buf, len );
+#endif
+#if defined(POLARSSL_SHA512_C)
+    sha512_update( &ssl->handshake->fin_sha512, buf, len );
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+}
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_1)
+static void ssl_update_checksum_md5sha1( ssl_context *ssl,
+                                         const unsigned char *buf, size_t len )
+{
+     md5_update( &ssl->handshake->fin_md5 , buf, len );
+    sha1_update( &ssl->handshake->fin_sha1, buf, len );
+}
+#endif
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+static void ssl_update_checksum_sha256( ssl_context *ssl,
+                                        const unsigned char *buf, size_t len )
+{
+    sha256_update( &ssl->handshake->fin_sha256, buf, len );
+}
+#endif
+
+#if defined(POLARSSL_SHA512_C)
+static void ssl_update_checksum_sha384( ssl_context *ssl,
+                                        const unsigned char *buf, size_t len )
+{
+    sha512_update( &ssl->handshake->fin_sha512, buf, len );
+}
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+static void ssl_calc_finished_ssl(
+                ssl_context *ssl, unsigned char *buf, int from )
+{
+    const char *sender;
+    md5_context  md5;
+    sha1_context sha1;
+
+    unsigned char padbuf[48];
+    unsigned char md5sum[16];
+    unsigned char sha1sum[20];
+
+    ssl_session *session = ssl->session_negotiate;
+    if( !session )
+        session = ssl->session;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc  finished ssl" ) );
+
+    memcpy( &md5 , &ssl->handshake->fin_md5 , sizeof(md5_context)  );
+    memcpy( &sha1, &ssl->handshake->fin_sha1, sizeof(sha1_context) );
+
+    /*
+     * SSLv3:
+     *   hash =
+     *      MD5( master + pad2 +
+     *          MD5( handshake + sender + master + pad1 ) )
+     *   + SHA1( master + pad2 +
+     *         SHA1( handshake + sender + master + pad1 ) )
+     */
+
+#if !defined(POLARSSL_MD5_ALT)
+    SSL_DEBUG_BUF( 4, "finished  md5 state", (unsigned char *)
+                    md5.state, sizeof(  md5.state ) );
+#endif
+
+#if !defined(POLARSSL_SHA1_ALT)
+    SSL_DEBUG_BUF( 4, "finished sha1 state", (unsigned char *)
+                   sha1.state, sizeof( sha1.state ) );
+#endif
+
+    sender = ( from == SSL_IS_CLIENT ) ? "CLNT"
+                                       : "SRVR";
+
+    memset( padbuf, 0x36, 48 );
+
+    md5_update( &md5, (const unsigned char *) sender, 4 );
+    md5_update( &md5, session->master, 48 );
+    md5_update( &md5, padbuf, 48 );
+    md5_finish( &md5, md5sum );
+
+    sha1_update( &sha1, (const unsigned char *) sender, 4 );
+    sha1_update( &sha1, session->master, 48 );
+    sha1_update( &sha1, padbuf, 40 );
+    sha1_finish( &sha1, sha1sum );
+
+    memset( padbuf, 0x5C, 48 );
+
+    md5_starts( &md5 );
+    md5_update( &md5, session->master, 48 );
+    md5_update( &md5, padbuf, 48 );
+    md5_update( &md5, md5sum, 16 );
+    md5_finish( &md5, buf );
+
+    sha1_starts( &sha1 );
+    sha1_update( &sha1, session->master, 48 );
+    sha1_update( &sha1, padbuf , 40 );
+    sha1_update( &sha1, sha1sum, 20 );
+    sha1_finish( &sha1, buf + 16 );
+
+    SSL_DEBUG_BUF( 3, "calc finished result", buf, 36 );
+
+    memset(  &md5, 0, sizeof(  md5_context ) );
+    memset( &sha1, 0, sizeof( sha1_context ) );
+
+    memset(  padbuf, 0, sizeof(  padbuf ) );
+    memset(  md5sum, 0, sizeof(  md5sum ) );
+    memset( sha1sum, 0, sizeof( sha1sum ) );
+
+    SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
+}
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1)
+static void ssl_calc_finished_tls(
+                ssl_context *ssl, unsigned char *buf, int from )
+{
+    int len = 12;
+    const char *sender;
+    md5_context  md5;
+    sha1_context sha1;
+    unsigned char padbuf[36];
+
+    ssl_session *session = ssl->session_negotiate;
+    if( !session )
+        session = ssl->session;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc  finished tls" ) );
+
+    memcpy( &md5 , &ssl->handshake->fin_md5 , sizeof(md5_context)  );
+    memcpy( &sha1, &ssl->handshake->fin_sha1, sizeof(sha1_context) );
+
+    /*
+     * TLSv1:
+     *   hash = PRF( master, finished_label,
+     *               MD5( handshake ) + SHA1( handshake ) )[0..11]
+     */
+
+#if !defined(POLARSSL_MD5_ALT)
+    SSL_DEBUG_BUF( 4, "finished  md5 state", (unsigned char *)
+                    md5.state, sizeof(  md5.state ) );
+#endif
+
+#if !defined(POLARSSL_SHA1_ALT)
+    SSL_DEBUG_BUF( 4, "finished sha1 state", (unsigned char *)
+                   sha1.state, sizeof( sha1.state ) );
+#endif
+
+    sender = ( from == SSL_IS_CLIENT )
+             ? "client finished"
+             : "server finished";
+
+    md5_finish(  &md5, padbuf );
+    sha1_finish( &sha1, padbuf + 16 );
+
+    ssl->handshake->tls_prf( session->master, 48, sender,
+                             padbuf, 36, buf, len );
+
+    SSL_DEBUG_BUF( 3, "calc finished result", buf, len );
+
+    memset(  &md5, 0, sizeof(  md5_context ) );
+    memset( &sha1, 0, sizeof( sha1_context ) );
+
+    memset(  padbuf, 0, sizeof(  padbuf ) );
+
+    SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
+}
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 */
+
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+static void ssl_calc_finished_tls_sha256(
+                ssl_context *ssl, unsigned char *buf, int from )
+{
+    int len = 12;
+    const char *sender;
+    sha256_context sha256;
+    unsigned char padbuf[32];
+
+    ssl_session *session = ssl->session_negotiate;
+    if( !session )
+        session = ssl->session;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc  finished tls sha256" ) );
+
+    memcpy( &sha256, &ssl->handshake->fin_sha256, sizeof(sha256_context) );
+
+    /*
+     * TLSv1.2:
+     *   hash = PRF( master, finished_label,
+     *               Hash( handshake ) )[0.11]
+     */
+
+#if !defined(POLARSSL_SHA256_ALT)
+    SSL_DEBUG_BUF( 4, "finished sha2 state", (unsigned char *)
+                   sha256.state, sizeof( sha256.state ) );
+#endif
+
+    sender = ( from == SSL_IS_CLIENT )
+             ? "client finished"
+             : "server finished";
+
+    sha256_finish( &sha256, padbuf );
+
+    ssl->handshake->tls_prf( session->master, 48, sender,
+                             padbuf, 32, buf, len );
+
+    SSL_DEBUG_BUF( 3, "calc finished result", buf, len );
+
+    memset( &sha256, 0, sizeof( sha256_context ) );
+
+    memset(  padbuf, 0, sizeof(  padbuf ) );
+
+    SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
+}
+#endif /* POLARSSL_SHA256_C */
+
+#if defined(POLARSSL_SHA512_C)
+static void ssl_calc_finished_tls_sha384(
+                ssl_context *ssl, unsigned char *buf, int from )
+{
+    int len = 12;
+    const char *sender;
+    sha512_context sha512;
+    unsigned char padbuf[48];
+
+    ssl_session *session = ssl->session_negotiate;
+    if( !session )
+        session = ssl->session;
+
+    SSL_DEBUG_MSG( 2, ( "=> calc  finished tls sha384" ) );
+
+    memcpy( &sha512, &ssl->handshake->fin_sha512, sizeof(sha512_context) );
+
+    /*
+     * TLSv1.2:
+     *   hash = PRF( master, finished_label,
+     *               Hash( handshake ) )[0.11]
+     */
+
+#if !defined(POLARSSL_SHA512_ALT)
+    SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *)
+                   sha512.state, sizeof( sha512.state ) );
+#endif
+
+    sender = ( from == SSL_IS_CLIENT )
+             ? "client finished"
+             : "server finished";
+
+    sha512_finish( &sha512, padbuf );
+
+    ssl->handshake->tls_prf( session->master, 48, sender,
+                             padbuf, 48, buf, len );
+
+    SSL_DEBUG_BUF( 3, "calc finished result", buf, len );
+
+    memset( &sha512, 0, sizeof( sha512_context ) );
+
+    memset(  padbuf, 0, sizeof(  padbuf ) );
+
+    SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
+}
+#endif /* POLARSSL_SHA512_C */
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+void ssl_handshake_wrapup( ssl_context *ssl )
+{
+    int resume = ssl->handshake->resume;
+
+    SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
+
+    /*
+     * Free our handshake params
+     */
+    ssl_handshake_free( ssl->handshake );
+    polarssl_free( ssl->handshake );
+    ssl->handshake = NULL;
+
+    if( ssl->renegotiation == SSL_RENEGOTIATION )
+        ssl->renegotiation =  SSL_RENEGOTIATION_DONE;
+
+    /*
+     * Switch in our now active transform context
+     */
+    if( ssl->transform )
+    {
+        ssl_transform_free( ssl->transform );
+        polarssl_free( ssl->transform );
+    }
+    ssl->transform = ssl->transform_negotiate;
+    ssl->transform_negotiate = NULL;
+
+    if( ssl->session )
+    {
+        ssl_session_free( ssl->session );
+        polarssl_free( ssl->session );
+    }
+    ssl->session = ssl->session_negotiate;
+    ssl->session_negotiate = NULL;
+
+    /*
+     * Add cache entry
+     */
+    if( ssl->f_set_cache != NULL &&
+        ssl->session->length != 0 &&
+        resume == 0 )
+    {
+        if( ssl->f_set_cache( ssl->p_set_cache, ssl->session ) != 0 )
+            SSL_DEBUG_MSG( 1, ( "cache did not store session" ) );
+    }
+
+    ssl->state++;
+
+    SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
+}
+
+int ssl_write_finished( ssl_context *ssl )
+{
+    int ret, hash_len;
+
+    SSL_DEBUG_MSG( 2, ( "=> write finished" ) );
+
+    /*
+     * Set the out_msg pointer to the correct location based on IV length
+     */
+    if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
+    {
+        ssl->out_msg = ssl->out_iv + ssl->transform_negotiate->ivlen -
+                       ssl->transform_negotiate->fixed_ivlen;
+    }
+    else
+        ssl->out_msg = ssl->out_iv;
+
+    ssl->handshake->calc_finished( ssl, ssl->out_msg + 4, ssl->endpoint );
+
+    // TODO TLS/1.2 Hash length is determined by cipher suite (Page 63)
+    hash_len = ( ssl->minor_ver == SSL_MINOR_VERSION_0 ) ? 36 : 12;
+
+    ssl->verify_data_len = hash_len;
+    memcpy( ssl->own_verify_data, ssl->out_msg + 4, hash_len );
+
+    ssl->out_msglen  = 4 + hash_len;
+    ssl->out_msgtype = SSL_MSG_HANDSHAKE;
+    ssl->out_msg[0]  = SSL_HS_FINISHED;
+
+    /*
+     * In case of session resuming, invert the client and server
+     * ChangeCipherSpec messages order.
+     */
+    if( ssl->handshake->resume != 0 )
+    {
+        if( ssl->endpoint == SSL_IS_CLIENT )
+            ssl->state = SSL_HANDSHAKE_WRAPUP;
+        else
+            ssl->state = SSL_CLIENT_CHANGE_CIPHER_SPEC;
+    }
+    else
+        ssl->state++;
+
+    /*
+     * Switch to our negotiated transform and session parameters for outbound
+     * data.
+     */
+    SSL_DEBUG_MSG( 3, ( "switching to new transform spec for outbound data" ) );
+    ssl->transform_out = ssl->transform_negotiate;
+    ssl->session_out = ssl->session_negotiate;
+    memset( ssl->out_ctr, 0, 8 );
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_activate != NULL)
+    {
+        if( ( ret = ssl_hw_record_activate( ssl, SSL_CHANNEL_OUTBOUND ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_activate", ret );
+            return( POLARSSL_ERR_SSL_HW_ACCEL_FAILED );
+        }
+    }
+#endif
+
+    if( ( ret = ssl_write_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write finished" ) );
+
+    return( 0 );
+}
+
+int ssl_parse_finished( ssl_context *ssl )
+{
+    int ret;
+    unsigned int hash_len;
+    unsigned char buf[36];
+
+    SSL_DEBUG_MSG( 2, ( "=> parse finished" ) );
+
+    ssl->handshake->calc_finished( ssl, buf, ssl->endpoint ^ 1 );
+
+    /*
+     * Switch to our negotiated transform and session parameters for inbound
+     * data.
+     */
+    SSL_DEBUG_MSG( 3, ( "switching to new transform spec for inbound data" ) );
+    ssl->transform_in = ssl->transform_negotiate;
+    ssl->session_in = ssl->session_negotiate;
+    memset( ssl->in_ctr, 0, 8 );
+
+    /*
+     * Set the in_msg pointer to the correct location based on IV length
+     */
+    if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
+    {
+        ssl->in_msg = ssl->in_iv + ssl->transform_negotiate->ivlen -
+                      ssl->transform_negotiate->fixed_ivlen;
+    }
+    else
+        ssl->in_msg = ssl->in_iv;
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_activate != NULL)
+    {
+        if( ( ret = ssl_hw_record_activate( ssl, SSL_CHANNEL_INBOUND ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_activate", ret );
+            return( POLARSSL_ERR_SSL_HW_ACCEL_FAILED );
+        }
+    }
+#endif
+
+    if( ( ret = ssl_read_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_read_record", ret );
+        return( ret );
+    }
+
+    if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+    }
+
+    // TODO TLS/1.2 Hash length is determined by cipher suite (Page 63)
+    hash_len = ( ssl->minor_ver == SSL_MINOR_VERSION_0 ) ? 36 : 12;
+
+    if( ssl->in_msg[0] != SSL_HS_FINISHED ||
+        ssl->in_hslen  != 4 + hash_len )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        return( POLARSSL_ERR_SSL_BAD_HS_FINISHED );
+    }
+
+    if( safer_memcmp( ssl->in_msg + 4, buf, hash_len ) != 0 )
+    {
+        SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
+        return( POLARSSL_ERR_SSL_BAD_HS_FINISHED );
+    }
+
+    ssl->verify_data_len = hash_len;
+    memcpy( ssl->peer_verify_data, buf, hash_len );
+
+    if( ssl->handshake->resume != 0 )
+    {
+        if( ssl->endpoint == SSL_IS_CLIENT )
+            ssl->state = SSL_CLIENT_CHANGE_CIPHER_SPEC;
+
+        if( ssl->endpoint == SSL_IS_SERVER )
+            ssl->state = SSL_HANDSHAKE_WRAPUP;
+    }
+    else
+        ssl->state++;
+
+    SSL_DEBUG_MSG( 2, ( "<= parse finished" ) );
+
+    return( 0 );
+}
+
+static int ssl_handshake_init( ssl_context *ssl )
+{
+    if( ssl->transform_negotiate )
+        ssl_transform_free( ssl->transform_negotiate );
+    else
+    {
+        ssl->transform_negotiate =
+            (ssl_transform *) polarssl_malloc( sizeof(ssl_transform) );
+
+        if( ssl->transform_negotiate != NULL )
+            memset( ssl->transform_negotiate, 0, sizeof(ssl_transform) );
+    }
+
+    if( ssl->session_negotiate )
+        ssl_session_free( ssl->session_negotiate );
+    else
+    {
+        ssl->session_negotiate =
+            (ssl_session *) polarssl_malloc( sizeof(ssl_session) );
+
+        if( ssl->session_negotiate != NULL )
+            memset( ssl->session_negotiate, 0, sizeof(ssl_session) );
+    }
+
+    if( ssl->handshake )
+        ssl_handshake_free( ssl->handshake );
+    else
+    {
+        ssl->handshake = (ssl_handshake_params *)
+            polarssl_malloc( sizeof(ssl_handshake_params) );
+
+        if( ssl->handshake != NULL )
+            memset( ssl->handshake, 0, sizeof(ssl_handshake_params) );
+    }
+
+    if( ssl->handshake == NULL ||
+        ssl->transform_negotiate == NULL ||
+        ssl->session_negotiate == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "malloc() of ssl sub-contexts failed" ) );
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    }
+
+#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_1)
+     md5_starts( &ssl->handshake->fin_md5 );
+    sha1_starts( &ssl->handshake->fin_sha1 );
+#endif
+#if defined(POLARSSL_SSL_PROTO_TLS1_2)
+#if defined(POLARSSL_SHA256_C)
+    sha256_starts( &ssl->handshake->fin_sha256, 0 );
+#endif
+#if defined(POLARSSL_SHA512_C)
+    sha512_starts( &ssl->handshake->fin_sha512, 1 );
+#endif
+#endif /* POLARSSL_SSL_PROTO_TLS1_2 */
+
+    ssl->handshake->update_checksum = ssl_update_checksum_start;
+    ssl->handshake->sig_alg = SSL_HASH_SHA1;
+
+#if defined(POLARSSL_ECDH_C)
+    ecdh_init( &ssl->handshake->ecdh_ctx );
+#endif
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+    ssl->handshake->key_cert = ssl->key_cert;
+#endif
+
+    return( 0 );
+}
+
+/*
+ * Initialize an SSL context
+ */
+int ssl_init( ssl_context *ssl )
+{
+    int ret;
+    int len = SSL_BUFFER_LEN;
+    
+    void *sptr1 = ssl->f_dbg;
+    void *sptr2 = ssl->f_rng;
+
+//    SSL_DEBUG_MSG( 1, ( "ssl_init" ) );
+    memset( ssl, 0, sizeof( ssl_context ) );
+    
+    ssl->f_dbg = sptr1;
+    ssl->f_rng = sptr2;
+
+    /*
+     * Sane defaults
+     */
+    ssl->min_major_ver = SSL_MIN_MAJOR_VERSION;
+    ssl->min_minor_ver = SSL_MIN_MINOR_VERSION;
+    ssl->max_major_ver = SSL_MAX_MAJOR_VERSION;
+    ssl->max_minor_ver = SSL_MAX_MINOR_VERSION;
+
+    ssl_set_ciphersuites( ssl, ssl_list_ciphersuites() );
+
+#if defined(POLARSSL_DHM_C)
+    if( ( ret = mpi_read_string( &ssl->dhm_P, 16,
+                                 POLARSSL_DHM_RFC5114_MODP_1024_P) ) != 0 ||
+        ( ret = mpi_read_string( &ssl->dhm_G, 16,
+                                 POLARSSL_DHM_RFC5114_MODP_1024_G) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "mpi_read_string", ret );
+        return( ret );
+    }
+#endif
+
+    /*
+     * Prepare base structures
+     */
+    ssl->in_ctr = (unsigned char *) polarssl_malloc( len );
+    ssl->in_hdr = ssl->in_ctr +  8;
+    ssl->in_iv  = ssl->in_ctr + 13;
+    ssl->in_msg = ssl->in_ctr + 13;
+
+    if( ssl->in_ctr == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "malloc(%d bytes) failed", len ) );
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    }
+
+    ssl->out_ctr = (unsigned char *) polarssl_malloc( len );
+    ssl->out_hdr = ssl->out_ctr +  8;
+    ssl->out_iv  = ssl->out_ctr + 13;
+    ssl->out_msg = ssl->out_ctr + 13;
+
+    if( ssl->out_ctr == NULL )
+    {
+        SSL_DEBUG_MSG( 1, ( "malloc(%d bytes) failed", len ) );
+        polarssl_free( ssl->in_ctr );
+        ssl->in_ctr = NULL;
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    }
+
+    memset( ssl-> in_ctr, 0, SSL_BUFFER_LEN );
+    memset( ssl->out_ctr, 0, SSL_BUFFER_LEN );
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+    ssl->ticket_lifetime = SSL_DEFAULT_TICKET_LIFETIME;
+#endif
+
+#if defined(POLARSSL_SSL_SET_CURVES)
+    ssl->curve_list = ecp_grp_id_list( );
+#endif
+
+    if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
+        return( ret );
+
+    return( 0 );
+}
+
+/*
+ * Reset an initialized and used SSL context for re-use while retaining
+ * all application-set variables, function pointers and data.
+ */
+int ssl_session_reset( ssl_context *ssl )
+{
+    int ret;
+
+    ssl->state = SSL_HELLO_REQUEST;
+    ssl->renegotiation = SSL_INITIAL_HANDSHAKE;
+    ssl->secure_renegotiation = SSL_LEGACY_RENEGOTIATION;
+
+    ssl->verify_data_len = 0;
+    memset( ssl->own_verify_data, 0, 36 );
+    memset( ssl->peer_verify_data, 0, 36 );
+
+    ssl->in_offt = NULL;
+
+    ssl->in_msg = ssl->in_ctr + 13;
+    ssl->in_msgtype = 0;
+    ssl->in_msglen = 0;
+    ssl->in_left = 0;
+
+    ssl->in_hslen = 0;
+    ssl->nb_zero = 0;
+    ssl->record_read = 0;
+
+    ssl->out_msg = ssl->out_ctr + 13;
+    ssl->out_msgtype = 0;
+    ssl->out_msglen = 0;
+    ssl->out_left = 0;
+
+    ssl->transform_in = NULL;
+    ssl->transform_out = NULL;
+
+    memset( ssl->out_ctr, 0, SSL_BUFFER_LEN );
+    memset( ssl->in_ctr, 0, SSL_BUFFER_LEN );
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_reset != NULL)
+    {
+        SSL_DEBUG_MSG( 2, ( "going for ssl_hw_record_reset()" ) );
+        if( ( ret = ssl_hw_record_reset( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_hw_record_reset", ret );
+            return( POLARSSL_ERR_SSL_HW_ACCEL_FAILED );
+        }
+    }
+#endif
+
+    if( ssl->transform )
+    {
+        ssl_transform_free( ssl->transform );
+        polarssl_free( ssl->transform );
+        ssl->transform = NULL;
+    }
+
+    if( ssl->session )
+    {
+        ssl_session_free( ssl->session );
+        polarssl_free( ssl->session );
+        ssl->session = NULL;
+    }
+
+#if defined(POLARSSL_SSL_ALPN)
+    ssl->alpn_chosen = NULL;
+#endif
+
+    if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
+        return( ret );
+
+    return( 0 );
+}
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+/*
+ * Allocate and initialize ticket keys
+ */
+static int ssl_ticket_keys_init( ssl_context *ssl )
+{
+    int ret;
+    ssl_ticket_keys *tkeys;
+    unsigned char buf[16];
+
+    if( ssl->ticket_keys != NULL )
+        return( 0 );
+
+    tkeys = (ssl_ticket_keys *) polarssl_malloc( sizeof(ssl_ticket_keys) );
+    if( tkeys == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    if( ( ret = ssl->f_rng( ssl->p_rng, tkeys->key_name, 16 ) ) != 0 )
+    {
+        polarssl_free( tkeys );
+        return( ret );
+    }
+
+    if( ( ret = ssl->f_rng( ssl->p_rng, buf, 16 ) ) != 0 ||
+        ( ret = aes_setkey_enc( &tkeys->enc, buf, 128 ) ) != 0 ||
+        ( ret = aes_setkey_dec( &tkeys->dec, buf, 128 ) ) != 0 )
+    {
+        polarssl_free( tkeys );
+        return( ret );
+    }
+
+    if( ( ret = ssl->f_rng( ssl->p_rng, tkeys->mac_key, 16 ) ) != 0 )
+    {
+        polarssl_free( tkeys );
+        return( ret );
+    }
+
+    ssl->ticket_keys = tkeys;
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_SESSION_TICKETS */
+
+/*
+ * SSL set accessors
+ */
+void ssl_set_endpoint( ssl_context *ssl, int endpoint )
+{
+    ssl->endpoint   = endpoint;
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+    if( endpoint == SSL_IS_CLIENT )
+        ssl->session_tickets = SSL_SESSION_TICKETS_ENABLED;
+#endif
+}
+
+void ssl_set_authmode( ssl_context *ssl, int authmode )
+{
+    ssl->authmode   = authmode;
+}
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+void ssl_set_verify( ssl_context *ssl,
+                     int (*f_vrfy)(void *, x509_crt *, int, int *),
+                     void *p_vrfy )
+{
+    ssl->f_vrfy      = f_vrfy;
+    ssl->p_vrfy      = p_vrfy;
+}
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+void ssl_set_rng( ssl_context *ssl,
+                  int (*f_rng)(void *, unsigned char *, size_t),
+                  void *p_rng )
+{
+    ssl->f_rng      = f_rng;
+    ssl->p_rng      = p_rng;
+}
+
+void ssl_set_dbg( ssl_context *ssl,
+                  void (*f_dbg)(void *, int, const char *),
+                  void  *p_dbg )
+{
+    ssl->f_dbg      = f_dbg;
+    ssl->p_dbg      = p_dbg;
+}
+
+void ssl_set_bio( ssl_context *ssl,
+            int (*f_recv)(void *, unsigned char *, size_t), void *p_recv,
+            int (*f_send)(void *, const unsigned char *, size_t), void *p_send )
+{
+    ssl->f_recv     = f_recv;
+    ssl->f_send     = f_send;
+    ssl->p_recv     = p_recv;
+    ssl->p_send     = p_send;
+}
+
+void ssl_set_session_cache( ssl_context *ssl,
+        int (*f_get_cache)(void *, ssl_session *), void *p_get_cache,
+        int (*f_set_cache)(void *, const ssl_session *), void *p_set_cache )
+{
+    ssl->f_get_cache = f_get_cache;
+    ssl->p_get_cache = p_get_cache;
+    ssl->f_set_cache = f_set_cache;
+    ssl->p_set_cache = p_set_cache;
+}
+
+int ssl_set_session( ssl_context *ssl, const ssl_session *session )
+{
+    int ret;
+
+    if( ssl == NULL ||
+        session == NULL ||
+        ssl->session_negotiate == NULL ||
+        ssl->endpoint != SSL_IS_CLIENT )
+    {
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    if( ( ret = ssl_session_copy( ssl->session_negotiate, session ) ) != 0 )
+        return( ret );
+
+    ssl->handshake->resume = 1;
+
+    return( 0 );
+}
+
+void ssl_set_ciphersuites( ssl_context *ssl, const int *ciphersuites )
+{
+    ssl->ciphersuite_list[SSL_MINOR_VERSION_0] = ciphersuites;
+    ssl->ciphersuite_list[SSL_MINOR_VERSION_1] = ciphersuites;
+    ssl->ciphersuite_list[SSL_MINOR_VERSION_2] = ciphersuites;
+    ssl->ciphersuite_list[SSL_MINOR_VERSION_3] = ciphersuites;
+}
+
+void ssl_set_ciphersuites_for_version( ssl_context *ssl,
+                                       const int *ciphersuites,
+                                       int major, int minor )
+{
+    if( major != SSL_MAJOR_VERSION_3 )
+        return;
+
+    if( minor < SSL_MINOR_VERSION_0 || minor > SSL_MINOR_VERSION_3 )
+        return;
+
+    ssl->ciphersuite_list[minor] = ciphersuites;
+}
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+/* Add a new (empty) key_cert entry an return a pointer to it */
+static ssl_key_cert *ssl_add_key_cert( ssl_context *ssl )
+{
+    ssl_key_cert *key_cert, *last;
+
+    key_cert = (ssl_key_cert *) polarssl_malloc( sizeof(ssl_key_cert) );
+    if( key_cert == NULL )
+        return( NULL );
+
+    memset( key_cert, 0, sizeof( ssl_key_cert ) );
+
+    /* Append the new key_cert to the (possibly empty) current list */
+    if( ssl->key_cert == NULL )
+    {
+        ssl->key_cert = key_cert;
+        if( ssl->handshake != NULL )
+            ssl->handshake->key_cert = key_cert;
+    }
+    else
+    {
+        last = ssl->key_cert;
+        while( last->next != NULL )
+            last = last->next;
+        last->next = key_cert;
+    }
+
+    return key_cert;
+}
+
+void ssl_set_ca_chain( ssl_context *ssl, x509_crt *ca_chain,
+                       x509_crl *ca_crl, const char *peer_cn )
+{
+    ssl->ca_chain   = ca_chain;
+    ssl->ca_crl     = ca_crl;
+    ssl->peer_cn    = peer_cn;
+}
+
+int ssl_set_own_cert( ssl_context *ssl, x509_crt *own_cert,
+                       pk_context *pk_key )
+{
+    ssl_key_cert *key_cert = ssl_add_key_cert( ssl );
+
+    if( key_cert == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    key_cert->cert = own_cert;
+    key_cert->key  = pk_key;
+
+    return( 0 );
+}
+
+#if defined(POLARSSL_RSA_C)
+int ssl_set_own_cert_rsa( ssl_context *ssl, x509_crt *own_cert,
+                           rsa_context *rsa_key )
+{
+    int ret;
+    ssl_key_cert *key_cert = ssl_add_key_cert( ssl );
+
+    if( key_cert == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    key_cert->key = (pk_context *) polarssl_malloc( sizeof(pk_context) );
+    if( key_cert->key == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    pk_init( key_cert->key );
+
+    ret = pk_init_ctx( key_cert->key, pk_info_from_type( POLARSSL_PK_RSA ) );
+    if( ret != 0 )
+        return( ret );
+
+    if( ( ret = rsa_copy( pk_rsa( *key_cert->key ), rsa_key ) ) != 0 )
+        return( ret );
+
+    key_cert->cert = own_cert;
+    key_cert->key_own_alloc = 1;
+
+    return( 0 );
+}
+#endif /* POLARSSL_RSA_C */
+
+int ssl_set_own_cert_alt( ssl_context *ssl, x509_crt *own_cert,
+                          void *rsa_key,
+                          rsa_decrypt_func rsa_decrypt,
+                          rsa_sign_func rsa_sign,
+                          rsa_key_len_func rsa_key_len )
+{
+    int ret;
+    ssl_key_cert *key_cert = ssl_add_key_cert( ssl );
+
+    if( key_cert == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    key_cert->key = (pk_context *) polarssl_malloc( sizeof(pk_context) );
+    if( key_cert->key == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    pk_init( key_cert->key );
+
+    if( ( ret = pk_init_ctx_rsa_alt( key_cert->key, rsa_key,
+                                 rsa_decrypt, rsa_sign, rsa_key_len ) ) != 0 )
+        return( ret );
+
+    key_cert->cert = own_cert;
+    key_cert->key_own_alloc = 1;
+
+    return( 0 );
+}
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
+int ssl_set_psk( ssl_context *ssl, const unsigned char *psk, size_t psk_len,
+                 const unsigned char *psk_identity, size_t psk_identity_len )
+{
+    if( psk == NULL || psk_identity == NULL )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    /*
+     * The length will be check later anyway, but in case it is obviously
+     * too large, better abort now. The PMS is as follows:
+     * other_len (2 bytes) + other + psk_len (2 bytes) + psk
+     */
+    if( psk_len + 4 > POLARSSL_PREMASTER_SIZE )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    if( ssl->psk != NULL )
+    {
+        polarssl_free( ssl->psk );
+        polarssl_free( ssl->psk_identity );
+    }
+
+    ssl->psk_len = psk_len;
+    ssl->psk_identity_len = psk_identity_len;
+
+    ssl->psk = (unsigned char *) polarssl_malloc( ssl->psk_len );
+    ssl->psk_identity = (unsigned char *)
+                                polarssl_malloc( ssl->psk_identity_len );
+
+    if( ssl->psk == NULL || ssl->psk_identity == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    memcpy( ssl->psk, psk, ssl->psk_len );
+    memcpy( ssl->psk_identity, psk_identity, ssl->psk_identity_len );
+
+    return( 0 );
+}
+
+void ssl_set_psk_cb( ssl_context *ssl,
+                     int (*f_psk)(void *, ssl_context *, const unsigned char *,
+                     size_t),
+                     void *p_psk )
+{
+    ssl->f_psk = f_psk;
+    ssl->p_psk = p_psk;
+}
+#endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */
+
+#if defined(POLARSSL_DHM_C)
+int ssl_set_dh_param( ssl_context *ssl, const char *dhm_P, const char *dhm_G )
+{
+    int ret;
+
+    if( ( ret = mpi_read_string( &ssl->dhm_P, 16, dhm_P ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "mpi_read_string", ret );
+        return( ret );
+    }
+
+    if( ( ret = mpi_read_string( &ssl->dhm_G, 16, dhm_G ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "mpi_read_string", ret );
+        return( ret );
+    }
+
+    return( 0 );
+}
+
+int ssl_set_dh_param_ctx( ssl_context *ssl, dhm_context *dhm_ctx )
+{
+    int ret;
+
+    if( ( ret = mpi_copy(&ssl->dhm_P, &dhm_ctx->P) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "mpi_copy", ret );
+        return( ret );
+    }
+
+    if( ( ret = mpi_copy(&ssl->dhm_G, &dhm_ctx->G) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "mpi_copy", ret );
+        return( ret );
+    }
+
+    return( 0 );
+}
+#endif /* POLARSSL_DHM_C */
+
+#if defined(POLARSSL_SSL_SET_CURVES)
+/*
+ * Set the allowed elliptic curves
+ */
+void ssl_set_curves( ssl_context *ssl, const ecp_group_id *curve_list )
+{
+  ssl->curve_list = curve_list;
+}
+#endif
+
+#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
+int ssl_set_hostname( ssl_context *ssl, const char *hostname )
+{
+    if( hostname == NULL )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    ssl->hostname_len = strlen( hostname );
+
+    if( ssl->hostname_len + 1 == 0 )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    ssl->hostname = (unsigned char *) polarssl_malloc( ssl->hostname_len + 1 );
+
+    if( ssl->hostname == NULL )
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+
+    memcpy( ssl->hostname, (const unsigned char *) hostname,
+            ssl->hostname_len );
+
+    ssl->hostname[ssl->hostname_len] = '\0';
+
+    return( 0 );
+}
+
+void ssl_set_sni( ssl_context *ssl,
+                  int (*f_sni)(void *, ssl_context *,
+                                const unsigned char *, size_t),
+                  void *p_sni )
+{
+    ssl->f_sni = f_sni;
+    ssl->p_sni = p_sni;
+}
+#endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */
+
+#if defined(POLARSSL_SSL_ALPN)
+int ssl_set_alpn_protocols( ssl_context *ssl, const char **protos )
+{
+    size_t cur_len, tot_len;
+    const char **p;
+
+    /*
+     * "Empty strings MUST NOT be included and byte strings MUST NOT be
+     * truncated". Check lengths now rather than later.
+     */
+    tot_len = 0;
+    for( p = protos; *p != NULL; p++ )
+    {
+        cur_len = strlen( *p );
+        tot_len += cur_len;
+
+        if( cur_len == 0 || cur_len > 255 || tot_len > 65535 )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    ssl->alpn_list = protos;
+
+    return( 0 );
+}
+
+const char *ssl_get_alpn_protocol( const ssl_context *ssl )
+{
+    return ssl->alpn_chosen;
+}
+#endif /* POLARSSL_SSL_ALPN */
+
+void ssl_set_max_version( ssl_context *ssl, int major, int minor )
+{
+    if( major >= SSL_MIN_MAJOR_VERSION && major <= SSL_MAX_MAJOR_VERSION &&
+        minor >= SSL_MIN_MINOR_VERSION && minor <= SSL_MAX_MINOR_VERSION )
+    {
+        ssl->max_major_ver = major;
+        ssl->max_minor_ver = minor;
+    }
+}
+
+void ssl_set_min_version( ssl_context *ssl, int major, int minor )
+{
+    if( major >= SSL_MIN_MAJOR_VERSION && major <= SSL_MAX_MAJOR_VERSION &&
+        minor >= SSL_MIN_MINOR_VERSION && minor <= SSL_MAX_MINOR_VERSION )
+    {
+        ssl->min_major_ver = major;
+        ssl->min_minor_ver = minor;
+    }
+}
+
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
+int ssl_set_max_frag_len( ssl_context *ssl, unsigned char mfl_code )
+{
+    if( mfl_code >= SSL_MAX_FRAG_LEN_INVALID ||
+        mfl_code_to_length[mfl_code] > SSL_MAX_CONTENT_LEN )
+    {
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    ssl->mfl_code = mfl_code;
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
+
+#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
+int ssl_set_truncated_hmac( ssl_context *ssl, int truncate )
+{
+    if( ssl->endpoint != SSL_IS_CLIENT )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    ssl->trunc_hmac = truncate;
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
+
+void ssl_set_renegotiation( ssl_context *ssl, int renegotiation )
+{
+    ssl->disable_renegotiation = renegotiation;
+}
+
+void ssl_legacy_renegotiation( ssl_context *ssl, int allow_legacy )
+{
+    ssl->allow_legacy_renegotiation = allow_legacy;
+}
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+int ssl_set_session_tickets( ssl_context *ssl, int use_tickets )
+{
+    ssl->session_tickets = use_tickets;
+
+    if( ssl->endpoint == SSL_IS_CLIENT )
+        return( 0 );
+
+    if( ssl->f_rng == NULL )
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+    return( ssl_ticket_keys_init( ssl ) );
+}
+
+void ssl_set_session_ticket_lifetime( ssl_context *ssl, int lifetime )
+{
+    ssl->ticket_lifetime = lifetime;
+}
+#endif /* POLARSSL_SSL_SESSION_TICKETS */
+
+/*
+ * SSL get accessors
+ */
+size_t ssl_get_bytes_avail( const ssl_context *ssl )
+{
+    return( ssl->in_offt == NULL ? 0 : ssl->in_msglen );
+}
+
+int ssl_get_verify_result( const ssl_context *ssl )
+{
+    return( ssl->session->verify_result );
+}
+
+const char *ssl_get_ciphersuite( const ssl_context *ssl )
+{
+    if( ssl == NULL || ssl->session == NULL )
+        return NULL;
+
+    return ssl_get_ciphersuite_name( ssl->session->ciphersuite );
+}
+
+const char *ssl_get_version( const ssl_context *ssl )
+{
+    switch( ssl->minor_ver )
+    {
+        case SSL_MINOR_VERSION_0:
+            return( "SSLv3.0" );
+
+        case SSL_MINOR_VERSION_1:
+            return( "TLSv1.0" );
+
+        case SSL_MINOR_VERSION_2:
+            return( "TLSv1.1" );
+
+        case SSL_MINOR_VERSION_3:
+            return( "TLSv1.2" );
+
+        default:
+            break;
+    }
+    return( "unknown" );
+}
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+const x509_crt *ssl_get_peer_cert( const ssl_context *ssl )
+{
+    if( ssl == NULL || ssl->session == NULL )
+        return NULL;
+
+    return ssl->session->peer_cert;
+}
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+int ssl_get_session( const ssl_context *ssl, ssl_session *dst )
+{
+    if( ssl == NULL ||
+        dst == NULL ||
+        ssl->session == NULL ||
+        ssl->endpoint != SSL_IS_CLIENT )
+    {
+        return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+    }
+
+    return( ssl_session_copy( dst, ssl->session ) );
+}
+
+/*
+ * Perform a single step of the SSL handshake
+ */
+int ssl_handshake_step( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+
+#if defined(POLARSSL_SSL_CLI_C)
+    if( ssl->endpoint == SSL_IS_CLIENT )
+        ret = ssl_handshake_client_step( ssl );
+#endif
+
+#if defined(POLARSSL_SSL_SRV_C)
+    if( ssl->endpoint == SSL_IS_SERVER )
+        ret = ssl_handshake_server_step( ssl );
+#endif
+
+    return( ret );
+}
+
+/*
+ * Perform the SSL handshake
+ */
+int ssl_handshake( ssl_context *ssl )
+{
+    int ret = 0;
+
+    SSL_DEBUG_MSG( 2, ( "=> handshake" ) );
+
+    while( ssl->state != SSL_HANDSHAKE_OVER )
+    {
+        ret = ssl_handshake_step( ssl );
+
+        if( ret != 0 )
+            break;
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= handshake" ) );
+
+    return( ret );
+}
+
+#if defined(POLARSSL_SSL_SRV_C)
+/*
+ * Write HelloRequest to request renegotiation on server
+ */
+static int ssl_write_hello_request( ssl_context *ssl )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> write hello request" ) );
+
+    ssl->out_msglen  = 4;
+    ssl->out_msgtype = SSL_MSG_HANDSHAKE;
+    ssl->out_msg[0]  = SSL_HS_HELLO_REQUEST;
+
+    if( ( ret = ssl_write_record( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+        return( ret );
+    }
+
+    ssl->renegotiation = SSL_RENEGOTIATION_PENDING;
+
+    SSL_DEBUG_MSG( 2, ( "<= write hello request" ) );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_SRV_C */
+
+/*
+ * Actually renegotiate current connection, triggered by either:
+ * - calling ssl_renegotiate() on client,
+ * - receiving a HelloRequest on client during ssl_read(),
+ * - receiving any handshake message on server during ssl_read() after the
+ *   initial handshake is completed
+ * If the handshake doesn't complete due to waiting for I/O, it will continue
+ * during the next calls to ssl_renegotiate() or ssl_read() respectively.
+ */
+static int ssl_start_renegotiation( ssl_context *ssl )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> renegotiate" ) );
+
+    if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
+        return( ret );
+
+    ssl->state = SSL_HELLO_REQUEST;
+    ssl->renegotiation = SSL_RENEGOTIATION;
+
+    if( ( ret = ssl_handshake( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_handshake", ret );
+        return( ret );
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= renegotiate" ) );
+
+    return( 0 );
+}
+
+/*
+ * Renegotiate current connection on client,
+ * or request renegotiation on server
+ */
+int ssl_renegotiate( ssl_context *ssl )
+{
+    int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE;
+
+#if defined(POLARSSL_SSL_SRV_C)
+    /* On server, just send the request */
+    if( ssl->endpoint == SSL_IS_SERVER )
+    {
+        if( ssl->state != SSL_HANDSHAKE_OVER )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+        return( ssl_write_hello_request( ssl ) );
+    }
+#endif /* POLARSSL_SSL_SRV_C */
+
+#if defined(POLARSSL_SSL_CLI_C)
+    /*
+     * On client, either start the renegotiation process or,
+     * if already in progress, continue the handshake
+     */
+    if( ssl->renegotiation != SSL_RENEGOTIATION )
+    {
+        if( ssl->state != SSL_HANDSHAKE_OVER )
+            return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+        if( ( ret = ssl_start_renegotiation( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_start_renegotiation", ret );
+            return( ret );
+        }
+    }
+    else
+    {
+        if( ( ret = ssl_handshake( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_handshake", ret );
+            return( ret );
+        }
+    }
+#endif /* POLARSSL_SSL_CLI_C */
+
+    return( ret );
+}
+
+/*
+ * Receive application data decrypted from the SSL layer
+ */
+int ssl_read( ssl_context *ssl, unsigned char *buf, size_t len )
+{
+    int ret;
+    size_t n;
+
+    SSL_DEBUG_MSG( 2, ( "=> read" ) );
+
+    if( ssl->state != SSL_HANDSHAKE_OVER )
+    {
+        if( ( ret = ssl_handshake( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_handshake", ret );
+            return( ret );
+        }
+    }
+
+    if( ssl->in_offt == NULL )
+    {
+        if( ( ret = ssl_read_record( ssl ) ) != 0 )
+        {
+            if( ret == POLARSSL_ERR_SSL_CONN_EOF )
+                return( 0 );
+
+            SSL_DEBUG_RET( 1, "ssl_read_record", ret );
+            return( ret );
+        }
+
+        if( ssl->in_msglen  == 0 &&
+            ssl->in_msgtype == SSL_MSG_APPLICATION_DATA )
+        {
+            /*
+             * OpenSSL sends empty messages to randomize the IV
+             */
+            if( ( ret = ssl_read_record( ssl ) ) != 0 )
+            {
+                if( ret == POLARSSL_ERR_SSL_CONN_EOF )
+                    return( 0 );
+
+                SSL_DEBUG_RET( 1, "ssl_read_record", ret );
+                return( ret );
+            }
+        }
+
+        if( ssl->in_msgtype == SSL_MSG_HANDSHAKE )
+        {
+            SSL_DEBUG_MSG( 1, ( "received handshake message" ) );
+
+            if( ssl->endpoint == SSL_IS_CLIENT &&
+                ( ssl->in_msg[0] != SSL_HS_HELLO_REQUEST ||
+                  ssl->in_hslen != 4 ) )
+            {
+                SSL_DEBUG_MSG( 1, ( "handshake received (not HelloRequest)" ) );
+                return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+            }
+
+            if( ssl->disable_renegotiation == SSL_RENEGOTIATION_DISABLED ||
+                ( ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
+                  ssl->allow_legacy_renegotiation ==
+                                                SSL_LEGACY_NO_RENEGOTIATION ) )
+            {
+                SSL_DEBUG_MSG( 3, ( "ignoring renegotiation, sending alert" ) );
+
+#if defined(POLARSSL_SSL_PROTO_SSL3)
+                if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
+                {
+                    /*
+                     * SSLv3 does not have a "no_renegotiation" alert
+                     */
+                    if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
+                        return( ret );
+                }
+                else
+#endif /* POLARSSL_SSL_PROTO_SSL3 */
+#if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \
+    defined(POLARSSL_SSL_PROTO_TLS1_2)
+                if( ssl->minor_ver >= SSL_MINOR_VERSION_1 )
+                {
+                    if( ( ret = ssl_send_alert_message( ssl,
+                                    SSL_ALERT_LEVEL_WARNING,
+                                    SSL_ALERT_MSG_NO_RENEGOTIATION ) ) != 0 )
+                    {
+                        return( ret );
+                    }
+                }
+                else
+#endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 ||
+          POLARSSL_SSL_PROTO_TLS1_2 */
+                {
+                    SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+                    return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
+                }
+            }
+            else
+            {
+                if( ( ret = ssl_start_renegotiation( ssl ) ) != 0 )
+                {
+                    SSL_DEBUG_RET( 1, "ssl_start_renegotiation", ret );
+                    return( ret );
+                }
+
+                return( POLARSSL_ERR_NET_WANT_READ );
+            }
+        }
+        else if( ssl->renegotiation == SSL_RENEGOTIATION_PENDING )
+        {
+            SSL_DEBUG_MSG( 1, ( "renegotiation requested, "
+                                "but not honored by client" ) );
+            return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+        }
+        else if( ssl->in_msgtype != SSL_MSG_APPLICATION_DATA )
+        {
+            SSL_DEBUG_MSG( 1, ( "bad application data message" ) );
+            return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
+        }
+
+        ssl->in_offt = ssl->in_msg;
+    }
+
+    n = ( len < ssl->in_msglen )
+        ? len : ssl->in_msglen;
+
+    memcpy( buf, ssl->in_offt, n );
+    ssl->in_msglen -= n;
+
+    if( ssl->in_msglen == 0 )
+        /* all bytes consumed  */
+        ssl->in_offt = NULL;
+    else
+        /* more data available */
+        ssl->in_offt += n;
+
+    SSL_DEBUG_MSG( 2, ( "<= read" ) );
+
+    return( (int) n );
+}
+
+/*
+ * Send application data to be encrypted by the SSL layer
+ */
+int ssl_write( ssl_context *ssl, const unsigned char *buf, size_t len )
+{
+    int ret;
+    size_t n;
+    unsigned int max_len = SSL_MAX_CONTENT_LEN;
+
+    SSL_DEBUG_MSG( 2, ( "=> write" ) );
+
+    if( ssl->state != SSL_HANDSHAKE_OVER )
+    {
+        if( ( ret = ssl_handshake( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_handshake", ret );
+            return( ret );
+        }
+    }
+
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
+    /*
+     * Assume mfl_code is correct since it was checked when set
+     */
+    max_len = mfl_code_to_length[ssl->mfl_code];
+
+    /*
+     * Check if a smaller max length was negotiated
+     */
+    if( ssl->session_out != NULL &&
+        mfl_code_to_length[ssl->session_out->mfl_code] < max_len )
+    {
+        max_len = mfl_code_to_length[ssl->session_out->mfl_code];
+    }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
+
+    n = ( len < max_len) ? len : max_len;
+
+    if( ssl->out_left != 0 )
+    {
+        if( ( ret = ssl_flush_output( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_flush_output", ret );
+            return( ret );
+        }
+    }
+    else
+    {
+        ssl->out_msglen  = n;
+        ssl->out_msgtype = SSL_MSG_APPLICATION_DATA;
+        memcpy( ssl->out_msg, buf, n );
+
+        if( ( ret = ssl_write_record( ssl ) ) != 0 )
+        {
+            SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+            return( ret );
+        }
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write" ) );
+
+    return( (int) n );
+}
+
+/*
+ * Notify the peer that the connection is being closed
+ */
+int ssl_close_notify( ssl_context *ssl )
+{
+    int ret;
+
+    SSL_DEBUG_MSG( 2, ( "=> write close notify" ) );
+
+    if( ( ret = ssl_flush_output( ssl ) ) != 0 )
+    {
+        SSL_DEBUG_RET( 1, "ssl_flush_output", ret );
+        return( ret );
+    }
+
+    if( ssl->state == SSL_HANDSHAKE_OVER )
+    {
+        if( ( ret = ssl_send_alert_message( ssl,
+                        SSL_ALERT_LEVEL_WARNING,
+                        SSL_ALERT_MSG_CLOSE_NOTIFY ) ) != 0 )
+        {
+            return( ret );
+        }
+    }
+
+    SSL_DEBUG_MSG( 2, ( "<= write close notify" ) );
+
+    return( ret );
+}
+
+void ssl_transform_free( ssl_transform *transform )
+{
+#if defined(POLARSSL_ZLIB_SUPPORT)
+    deflateEnd( &transform->ctx_deflate );
+    inflateEnd( &transform->ctx_inflate );
+#endif
+
+    cipher_free_ctx( &transform->cipher_ctx_enc );
+    cipher_free_ctx( &transform->cipher_ctx_dec );
+
+    md_free_ctx( &transform->md_ctx_enc );
+    md_free_ctx( &transform->md_ctx_dec );
+
+    memset( transform, 0, sizeof( ssl_transform ) );
+}
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+static void ssl_key_cert_free( ssl_key_cert *key_cert )
+{
+    ssl_key_cert *cur = key_cert, *next;
+
+    while( cur != NULL )
+    {
+        next = cur->next;
+
+        if( cur->key_own_alloc )
+        {
+            pk_free( cur->key );
+            polarssl_free( cur->key );
+        }
+        polarssl_free( cur );
+
+        cur = next;
+    }
+}
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+void ssl_handshake_free( ssl_handshake_params *handshake )
+{
+#if defined(POLARSSL_DHM_C)
+    dhm_free( &handshake->dhm_ctx );
+#endif
+#if defined(POLARSSL_ECDH_C)
+    ecdh_free( &handshake->ecdh_ctx );
+#endif
+
+#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
+    /* explicit void pointer cast for buggy MS compiler */
+    polarssl_free( (void *) handshake->curves );
+#endif
+
+#if defined(POLARSSL_X509_CRT_PARSE_C) && \
+    defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
+    /*
+     * Free only the linked list wrapper, not the keys themselves
+     * since the belong to the SNI callback
+     */
+    if( handshake->sni_key_cert != NULL )
+    {
+        ssl_key_cert *cur = handshake->sni_key_cert, *next;
+
+        while( cur != NULL )
+        {
+            next = cur->next;
+            polarssl_free( cur );
+            cur = next;
+        }
+    }
+#endif /* POLARSSL_X509_CRT_PARSE_C && POLARSSL_SSL_SERVER_NAME_INDICATION */
+
+    memset( handshake, 0, sizeof( ssl_handshake_params ) );
+}
+
+void ssl_session_free( ssl_session *session )
+{
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+    if( session->peer_cert != NULL )
+    {
+        x509_crt_free( session->peer_cert );
+        polarssl_free( session->peer_cert );
+    }
+#endif
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+    polarssl_free( session->ticket );
+#endif
+
+    memset( session, 0, sizeof( ssl_session ) );
+}
+
+/*
+ * Free an SSL context
+ */
+void ssl_free( ssl_context *ssl )
+{
+    SSL_DEBUG_MSG( 2, ( "=> free" ) );
+
+    if( ssl->out_ctr != NULL )
+    {
+        memset( ssl->out_ctr, 0, SSL_BUFFER_LEN );
+        polarssl_free( ssl->out_ctr );
+    }
+
+    if( ssl->in_ctr != NULL )
+    {
+        memset( ssl->in_ctr, 0, SSL_BUFFER_LEN );
+        polarssl_free( ssl->in_ctr );
+    }
+
+#if defined(POLARSSL_ZLIB_SUPPORT)
+    if( ssl->compress_buf != NULL )
+    {
+        memset( ssl->compress_buf, 0, SSL_BUFFER_LEN );
+        polarssl_free( ssl->compress_buf );
+    }
+#endif
+
+#if defined(POLARSSL_DHM_C)
+    mpi_free( &ssl->dhm_P );
+    mpi_free( &ssl->dhm_G );
+#endif
+
+    if( ssl->transform )
+    {
+        ssl_transform_free( ssl->transform );
+        polarssl_free( ssl->transform );
+    }
+
+    if( ssl->handshake )
+    {
+        ssl_handshake_free( ssl->handshake );
+        ssl_transform_free( ssl->transform_negotiate );
+        ssl_session_free( ssl->session_negotiate );
+
+        polarssl_free( ssl->handshake );
+        polarssl_free( ssl->transform_negotiate );
+        polarssl_free( ssl->session_negotiate );
+    }
+
+    if( ssl->session )
+    {
+        ssl_session_free( ssl->session );
+        polarssl_free( ssl->session );
+    }
+
+#if defined(POLARSSL_SSL_SESSION_TICKETS)
+    polarssl_free( ssl->ticket_keys );
+#endif
+
+#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION)
+    if ( ssl->hostname != NULL )
+    {
+        memset( ssl->hostname, 0, ssl->hostname_len );
+        polarssl_free( ssl->hostname );
+        ssl->hostname_len = 0;
+    }
+#endif
+
+#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
+    if( ssl->psk != NULL )
+    {
+        memset( ssl->psk, 0, ssl->psk_len );
+        memset( ssl->psk_identity, 0, ssl->psk_identity_len );
+        polarssl_free( ssl->psk );
+        polarssl_free( ssl->psk_identity );
+        ssl->psk_len = 0;
+        ssl->psk_identity_len = 0;
+    }
+#endif
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+    ssl_key_cert_free( ssl->key_cert );
+#endif
+
+#if defined(POLARSSL_SSL_HW_RECORD_ACCEL)
+    if( ssl_hw_record_finish != NULL )
+    {
+        SSL_DEBUG_MSG( 2, ( "going for ssl_hw_record_finish()" ) );
+        ssl_hw_record_finish( ssl );
+    }
+#endif
+
+    SSL_DEBUG_MSG( 2, ( "<= free" ) );
+
+    /* Actually clear after last debug message */
+    memset( ssl, 0, sizeof( ssl_context ) );
+}
+
+#if defined(POLARSSL_PK_C)
+/*
+ * Convert between POLARSSL_PK_XXX and SSL_SIG_XXX
+ */
+unsigned char ssl_sig_from_pk( pk_context *pk )
+{
+#if defined(POLARSSL_RSA_C)
+    if( pk_can_do( pk, POLARSSL_PK_RSA ) )
+        return( SSL_SIG_RSA );
+#endif
+#if defined(POLARSSL_ECDSA_C)
+    if( pk_can_do( pk, POLARSSL_PK_ECDSA ) )
+        return( SSL_SIG_ECDSA );
+#endif
+    return( SSL_SIG_ANON );
+}
+
+pk_type_t ssl_pk_alg_from_sig( unsigned char sig )
+{
+    switch( sig )
+    {
+#if defined(POLARSSL_RSA_C)
+        case SSL_SIG_RSA:
+            return( POLARSSL_PK_RSA );
+#endif
+#if defined(POLARSSL_ECDSA_C)
+        case SSL_SIG_ECDSA:
+            return( POLARSSL_PK_ECDSA );
+#endif
+        default:
+            return( POLARSSL_PK_NONE );
+    }
+}
+#endif /* POLARSSL_PK_C */
+
+/*
+ * Convert between SSL_HASH_XXX and POLARSSL_MD_XXX
+ */
+md_type_t ssl_md_alg_from_hash( unsigned char hash )
+{
+    switch( hash )
+    {
+#if defined(POLARSSL_MD5_C)
+        case SSL_HASH_MD5:
+            return( POLARSSL_MD_MD5 );
+#endif
+#if defined(POLARSSL_SHA1_C)
+        case SSL_HASH_SHA1:
+            return( POLARSSL_MD_SHA1 );
+#endif
+#if defined(POLARSSL_SHA256_C)
+        case SSL_HASH_SHA224:
+            return( POLARSSL_MD_SHA224 );
+        case SSL_HASH_SHA256:
+            return( POLARSSL_MD_SHA256 );
+#endif
+#if defined(POLARSSL_SHA512_C)
+        case SSL_HASH_SHA384:
+            return( POLARSSL_MD_SHA384 );
+        case SSL_HASH_SHA512:
+            return( POLARSSL_MD_SHA512 );
+#endif
+        default:
+            return( POLARSSL_MD_NONE );
+    }
+}
+
+#if defined(POLARSSL_SSL_SET_CURVES)
+/*
+ * Check is a curve proposed by the peer is in our list.
+ * Return 1 if we're willing to use it, 0 otherwise.
+ */
+int ssl_curve_is_acceptable( const ssl_context *ssl, ecp_group_id grp_id )
+{
+    const ecp_group_id *gid;
+
+    for( gid = ssl->curve_list; *gid != POLARSSL_ECP_DP_NONE; gid++ )
+        if( *gid == grp_id )
+            return( 1 );
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_SET_CURVES */
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+int ssl_check_cert_usage( const x509_crt *cert,
+                          const ssl_ciphersuite_t *ciphersuite,
+                          int cert_endpoint )
+{
+#if defined(POLARSSL_X509_CHECK_KEY_USAGE)
+    int usage = 0;
+#endif
+#if defined(POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE)
+    const char *ext_oid;
+    size_t ext_len;
+#endif
+
+#if !defined(POLARSSL_X509_CHECK_KEY_USAGE) &&          \
+    !defined(POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE)
+    ((void) cert);
+    ((void) cert_endpoint);
+#endif
+
+#if defined(POLARSSL_X509_CHECK_KEY_USAGE)
+    if( cert_endpoint == SSL_IS_SERVER )
+    {
+        /* Server part of the key exchange */
+        switch( ciphersuite->key_exchange )
+        {
+            case POLARSSL_KEY_EXCHANGE_RSA:
+            case POLARSSL_KEY_EXCHANGE_RSA_PSK:
+                usage = KU_KEY_ENCIPHERMENT;
+                break;
+
+            case POLARSSL_KEY_EXCHANGE_DHE_RSA:
+            case POLARSSL_KEY_EXCHANGE_ECDHE_RSA:
+            case POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA:
+                usage = KU_DIGITAL_SIGNATURE;
+                break;
+
+            case POLARSSL_KEY_EXCHANGE_ECDH_RSA:
+            case POLARSSL_KEY_EXCHANGE_ECDH_ECDSA:
+                usage = KU_KEY_AGREEMENT;
+                break;
+
+            /* Don't use default: we want warnings when adding new values */
+            case POLARSSL_KEY_EXCHANGE_NONE:
+            case POLARSSL_KEY_EXCHANGE_PSK:
+            case POLARSSL_KEY_EXCHANGE_DHE_PSK:
+            case POLARSSL_KEY_EXCHANGE_ECDHE_PSK:
+                usage = 0;
+        }
+    }
+    else
+    {
+        /* Client auth: we only implement rsa_sign and ecdsa_sign for now */
+        usage = KU_DIGITAL_SIGNATURE;
+    }
+
+    if( x509_crt_check_key_usage( cert, usage ) != 0 )
+        return( -1 );
+#else
+    ((void) ciphersuite);
+#endif /* POLARSSL_X509_CHECK_KEY_USAGE */
+
+#if defined(POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE)
+    if( cert_endpoint == SSL_IS_SERVER )
+    {
+        ext_oid = OID_SERVER_AUTH;
+        ext_len = OID_SIZE( OID_SERVER_AUTH );
+    }
+    else
+    {
+        ext_oid = OID_CLIENT_AUTH;
+        ext_len = OID_SIZE( OID_CLIENT_AUTH );
+    }
+
+    if( x509_crt_check_extended_key_usage( cert, ext_oid, ext_len ) != 0 )
+        return( -1 );
+#endif /* POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE */
+
+    return( 0 );
+}
+#endif /* POLARSSL_X509_CRT_PARSE_C */
+
+#endif /* POLARSSL_SSL_TLS_C */
+
+