/src/openthread/third_party/mbedtls/repo/library/ssl_tls.c

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/*
 *  SSLv3/TLSv1 shared functions
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
/*
 *  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
 */

#include "common.h"

#if defined(MBEDTLS_SSL_TLS_C)

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc    calloc
#define mbedtls_free      free
#endif

#include "mbedtls/ssl.h"
#include "mbedtls/ssl_internal.h"
#include "mbedtls/debug.h"
#include "mbedtls/error.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/version.h"
#include "mbedtls/constant_time.h"

#include <string.h>

#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "mbedtls/psa_util.h"
#include "psa/crypto.h"
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
#include "mbedtls/oid.h"
#endif

#if defined(MBEDTLS_SSL_PROTO_DTLS)

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
/* Top-level Connection ID API */

int mbedtls_ssl_conf_cid( mbedtls_ssl_config *conf,
                          size_t len,
                          int ignore_other_cid )
{
    if( len > MBEDTLS_SSL_CID_IN_LEN_MAX )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    if( ignore_other_cid != MBEDTLS_SSL_UNEXPECTED_CID_FAIL &&
        ignore_other_cid != MBEDTLS_SSL_UNEXPECTED_CID_IGNORE )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    conf->ignore_unexpected_cid = ignore_other_cid;
    conf->cid_len = len;
    return( 0 );
}

int mbedtls_ssl_set_cid( mbedtls_ssl_context *ssl,
                         int enable,
                         unsigned char const *own_cid,
                         size_t own_cid_len )
{
    if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    ssl->negotiate_cid = enable;
    if( enable == MBEDTLS_SSL_CID_DISABLED )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Disable use of CID extension." ) );
        return( 0 );
    }
    MBEDTLS_SSL_DEBUG_MSG( 3, ( "Enable use of CID extension." ) );
    MBEDTLS_SSL_DEBUG_BUF( 3, "Own CID", own_cid, own_cid_len );

    if( own_cid_len != ssl->conf->cid_len )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "CID length %u does not match CID length %u in config",
                                    (unsigned) own_cid_len,
                                    (unsigned) ssl->conf->cid_len ) );
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    memcpy( ssl->own_cid, own_cid, own_cid_len );
    /* Truncation is not an issue here because
     * MBEDTLS_SSL_CID_IN_LEN_MAX at most 255. */
    ssl->own_cid_len = (uint8_t) own_cid_len;

    return( 0 );
}

int mbedtls_ssl_get_peer_cid( mbedtls_ssl_context *ssl,
                     int *enabled,
                     unsigned char peer_cid[ MBEDTLS_SSL_CID_OUT_LEN_MAX ],
                     size_t *peer_cid_len )
{
    *enabled = MBEDTLS_SSL_CID_DISABLED;

    if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ||
        ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    /* We report MBEDTLS_SSL_CID_DISABLED in case the CID extensions
     * were used, but client and server requested the empty CID.
     * This is indistinguishable from not using the CID extension
     * in the first place. */
    if( ssl->transform_in->in_cid_len  == 0 &&
        ssl->transform_in->out_cid_len == 0 )
    {
        return( 0 );
    }

    if( peer_cid_len != NULL )
    {
        *peer_cid_len = ssl->transform_in->out_cid_len;
        if( peer_cid != NULL )
        {
            memcpy( peer_cid, ssl->transform_in->out_cid,
                    ssl->transform_in->out_cid_len );
        }
    }

    *enabled = MBEDTLS_SSL_CID_ENABLED;

    return( 0 );
}
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

#endif /* MBEDTLS_SSL_PROTO_DTLS */

#if defined(MBEDTLS_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 ssl_mfl_code_to_length( int mfl )
{
    switch( mfl )
    {
    case MBEDTLS_SSL_MAX_FRAG_LEN_NONE:
        return ( MBEDTLS_TLS_EXT_ADV_CONTENT_LEN );
    case MBEDTLS_SSL_MAX_FRAG_LEN_512:
        return 512;
    case MBEDTLS_SSL_MAX_FRAG_LEN_1024:
        return 1024;
    case MBEDTLS_SSL_MAX_FRAG_LEN_2048:
        return 2048;
    case MBEDTLS_SSL_MAX_FRAG_LEN_4096:
        return 4096;
    default:
        return ( MBEDTLS_TLS_EXT_ADV_CONTENT_LEN );
    }
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

int mbedtls_ssl_session_copy( mbedtls_ssl_session *dst,
                              const mbedtls_ssl_session *src )
{
    mbedtls_ssl_session_free( dst );
    memcpy( dst, src, sizeof( mbedtls_ssl_session ) );

#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
    dst->ticket = NULL;
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)

#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
    if( src->peer_cert != NULL )
    {
        int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

        dst->peer_cert = mbedtls_calloc( 1, sizeof(mbedtls_x509_crt) );
        if( dst->peer_cert == NULL )
            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

        mbedtls_x509_crt_init( dst->peer_cert );

        if( ( ret = mbedtls_x509_crt_parse_der( dst->peer_cert, src->peer_cert->raw.p,
                                        src->peer_cert->raw.len ) ) != 0 )
        {
            mbedtls_free( dst->peer_cert );
            dst->peer_cert = NULL;
            return( ret );
        }
    }
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
    if( src->peer_cert_digest != NULL )
    {
        dst->peer_cert_digest =
            mbedtls_calloc( 1, src->peer_cert_digest_len );
        if( dst->peer_cert_digest == NULL )
            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

        memcpy( dst->peer_cert_digest, src->peer_cert_digest,
                src->peer_cert_digest_len );
        dst->peer_cert_digest_type = src->peer_cert_digest_type;
        dst->peer_cert_digest_len = src->peer_cert_digest_len;
    }
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */

#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
    if( src->ticket != NULL )
    {
        dst->ticket = mbedtls_calloc( 1, src->ticket_len );
        if( dst->ticket == NULL )
            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

        memcpy( dst->ticket, src->ticket, src->ticket_len );
    }
#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */

    return( 0 );
}

#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
static int resize_buffer( unsigned char **buffer, size_t len_new, size_t *len_old )
{
    unsigned char* resized_buffer = mbedtls_calloc( 1, len_new );
    if( resized_buffer == NULL )
        return -1;

    /* We want to copy len_new bytes when downsizing the buffer, and
     * len_old bytes when upsizing, so we choose the smaller of two sizes,
     * to fit one buffer into another. Size checks, ensuring that no data is
     * lost, are done outside of this function. */
    memcpy( resized_buffer, *buffer,
            ( len_new < *len_old ) ? len_new : *len_old );
    mbedtls_platform_zeroize( *buffer, *len_old );
    mbedtls_free( *buffer );

    *buffer = resized_buffer;
    *len_old = len_new;

    return 0;
}

static void handle_buffer_resizing( mbedtls_ssl_context *ssl, int downsizing,
                                    size_t in_buf_new_len,
                                    size_t out_buf_new_len )
{
    int modified = 0;
    size_t written_in = 0, iv_offset_in = 0, len_offset_in = 0;
    size_t written_out = 0, iv_offset_out = 0, len_offset_out = 0;
    if( ssl->in_buf != NULL )
    {
        written_in = ssl->in_msg - ssl->in_buf;
        iv_offset_in = ssl->in_iv - ssl->in_buf;
        len_offset_in = ssl->in_len - ssl->in_buf;
        if( downsizing ?
            ssl->in_buf_len > in_buf_new_len && ssl->in_left < in_buf_new_len :
            ssl->in_buf_len < in_buf_new_len )
        {
            if( resize_buffer( &ssl->in_buf, in_buf_new_len, &ssl->in_buf_len ) != 0 )
            {
                MBEDTLS_SSL_DEBUG_MSG( 1, ( "input buffer resizing failed - out of memory" ) );
            }
            else
            {
                MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reallocating in_buf to %" MBEDTLS_PRINTF_SIZET,
                                            in_buf_new_len ) );
                modified = 1;
            }
        }
    }

    if( ssl->out_buf != NULL )
    {
        written_out = ssl->out_msg - ssl->out_buf;
        iv_offset_out = ssl->out_iv - ssl->out_buf;
        len_offset_out = ssl->out_len - ssl->out_buf;
        if( downsizing ?
            ssl->out_buf_len > out_buf_new_len && ssl->out_left < out_buf_new_len :
            ssl->out_buf_len < out_buf_new_len )
        {
            if( resize_buffer( &ssl->out_buf, out_buf_new_len, &ssl->out_buf_len ) != 0 )
            {
                MBEDTLS_SSL_DEBUG_MSG( 1, ( "output buffer resizing failed - out of memory" ) );
            }
            else
            {
                MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reallocating out_buf to %" MBEDTLS_PRINTF_SIZET,
                                            out_buf_new_len ) );
                modified = 1;
            }
        }
    }
    if( modified )
    {
        /* Update pointers here to avoid doing it twice. */
        mbedtls_ssl_reset_in_out_pointers( ssl );
        /* Fields below might not be properly updated with record
         * splitting or with CID, so they are manually updated here. */
        ssl->out_msg = ssl->out_buf + written_out;
        ssl->out_len = ssl->out_buf + len_offset_out;
        ssl->out_iv = ssl->out_buf + iv_offset_out;

        ssl->in_msg = ssl->in_buf + written_in;
        ssl->in_len = ssl->in_buf + len_offset_in;
        ssl->in_iv = ssl->in_buf + iv_offset_in;
    }
}
#endif /* MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH */

/*
 * Key material generation
 */
#if defined(MBEDTLS_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 )
{
    int ret = 0;
    size_t i;
    mbedtls_md5_context md5;
    mbedtls_sha1_context sha1;
    unsigned char padding[16];
    unsigned char sha1sum[20];
    ((void)label);

    mbedtls_md5_init(  &md5  );
    mbedtls_sha1_init( &sha1 );

    /*
     *  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 );

        if( ( ret = mbedtls_sha1_starts_ret( &sha1 ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_sha1_update_ret( &sha1, padding, 1 + i ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_sha1_update_ret( &sha1, secret, slen ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_sha1_update_ret( &sha1, random, rlen ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_sha1_finish_ret( &sha1, sha1sum ) ) != 0 )
            goto exit;

        if( ( ret = mbedtls_md5_starts_ret( &md5 ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_md5_update_ret( &md5, secret, slen ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_md5_update_ret( &md5, sha1sum, 20 ) ) != 0 )
            goto exit;
        if( ( ret = mbedtls_md5_finish_ret( &md5, dstbuf + i * 16 ) ) != 0 )
            goto exit;
    }

exit:
    mbedtls_md5_free(  &md5  );
    mbedtls_sha1_free( &sha1 );

    mbedtls_platform_zeroize( padding, sizeof( padding ) );
    mbedtls_platform_zeroize( sha1sum, sizeof( sha1sum ) );

    return( ret );
}
#endif /* MBEDTLS_SSL_PROTO_SSL3 */

#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_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;
    size_t tmp_len = 0;
    unsigned char h_i[20];
    const mbedtls_md_info_t *md_info;
    mbedtls_md_context_t md_ctx;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    mbedtls_md_init( &md_ctx );

    tmp_len = 20 + strlen( label ) + rlen;
    tmp = mbedtls_calloc( 1, tmp_len );
    if( tmp == NULL )
    {
        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
        goto exit;
    }

    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]
     */
    if( ( md_info = mbedtls_md_info_from_type( MBEDTLS_MD_MD5 ) ) == NULL )
    {
        ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
        goto exit;
    }

    if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 1 ) ) != 0 )
    {
        goto exit;
    }

    ret = mbedtls_md_hmac_starts( &md_ctx, S1, hs );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_update( &md_ctx, tmp + 20, nb );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_finish( &md_ctx, 4 + tmp );
    if( ret != 0 )
        goto exit;

    for( i = 0; i < dlen; i += 16 )
    {
        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, 4 + tmp, 16 + nb );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, h_i );
        if( ret != 0 )
            goto exit;

        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, 4 + tmp, 16 );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, 4 + tmp );
        if( ret != 0 )
            goto exit;

        k = ( i + 16 > dlen ) ? dlen % 16 : 16;

        for( j = 0; j < k; j++ )
            dstbuf[i + j]  = h_i[j];
    }

    mbedtls_md_free( &md_ctx );

    /*
     * XOR out with P_sha1(secret,label+random)[0..dlen]
     */
    if( ( md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA1 ) ) == NULL )
    {
        ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
        goto exit;
    }

    if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 1 ) ) != 0 )
    {
        goto exit;
    }

    ret = mbedtls_md_hmac_starts( &md_ctx, S2, hs );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_update( &md_ctx, tmp + 20, nb );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_finish( &md_ctx, tmp );
    if( ret != 0 )
        goto exit;

    for( i = 0; i < dlen; i += 20 )
    {
        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, tmp, 20 + nb );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, h_i );
        if( ret != 0 )
            goto exit;

        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, tmp, 20 );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, tmp );
        if( ret != 0 )
            goto exit;

        k = ( i + 20 > dlen ) ? dlen % 20 : 20;

        for( j = 0; j < k; j++ )
            dstbuf[i + j] = (unsigned char)( dstbuf[i + j] ^ h_i[j] );
    }

exit:
    mbedtls_md_free( &md_ctx );

    mbedtls_platform_zeroize( tmp, tmp_len );
    mbedtls_platform_zeroize( h_i, sizeof( h_i ) );

    mbedtls_free( tmp );
    return( ret );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1) || MBEDTLS_SSL_PROTO_TLS1_1 */

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_USE_PSA_CRYPTO)

static psa_status_t setup_psa_key_derivation( psa_key_derivation_operation_t* derivation,
                                              psa_key_id_t key,
                                              psa_algorithm_t alg,
                                              const unsigned char* seed, size_t seed_length,
                                              const unsigned char* label, size_t label_length,
                                              size_t capacity )
{
    psa_status_t status;

    status = psa_key_derivation_setup( derivation, alg );
    if( status != PSA_SUCCESS )
        return( status );

    if( PSA_ALG_IS_TLS12_PRF( alg ) || PSA_ALG_IS_TLS12_PSK_TO_MS( alg ) )
    {
        status = psa_key_derivation_input_bytes( derivation,
                                                 PSA_KEY_DERIVATION_INPUT_SEED,
                                                 seed, seed_length );
        if( status != PSA_SUCCESS )
            return( status );

        if( mbedtls_svc_key_id_is_null( key ) )
        {
            status = psa_key_derivation_input_bytes(
                derivation, PSA_KEY_DERIVATION_INPUT_SECRET,
                NULL, 0 );
        }
        else
        {
            status = psa_key_derivation_input_key(
                derivation, PSA_KEY_DERIVATION_INPUT_SECRET, key );
        }
        if( status != PSA_SUCCESS )
            return( status );

        status = psa_key_derivation_input_bytes( derivation,
                                                 PSA_KEY_DERIVATION_INPUT_LABEL,
                                                 label, label_length );
        if( status != PSA_SUCCESS )
            return( status );
    }
    else
    {
        return( PSA_ERROR_NOT_SUPPORTED );
    }

    status = psa_key_derivation_set_capacity( derivation, capacity );
    if( status != PSA_SUCCESS )
        return( status );

    return( PSA_SUCCESS );
}

static int tls_prf_generic( mbedtls_md_type_t md_type,
                            const unsigned char *secret, size_t slen,
                            const char *label,
                            const unsigned char *random, size_t rlen,
                            unsigned char *dstbuf, size_t dlen )
{
    psa_status_t status;
    psa_algorithm_t alg;
    psa_key_id_t master_key = MBEDTLS_SVC_KEY_ID_INIT;
    psa_key_derivation_operation_t derivation =
        PSA_KEY_DERIVATION_OPERATION_INIT;

    if( md_type == MBEDTLS_MD_SHA384 )
        alg = PSA_ALG_TLS12_PRF(PSA_ALG_SHA_384);
    else
        alg = PSA_ALG_TLS12_PRF(PSA_ALG_SHA_256);

    /* Normally a "secret" should be long enough to be impossible to
     * find by brute force, and in particular should not be empty. But
     * this PRF is also used to derive an IV, in particular in EAP-TLS,
     * and for this use case it makes sense to have a 0-length "secret".
     * Since the key API doesn't allow importing a key of length 0,
     * keep master_key=0, which setup_psa_key_derivation() understands
     * to mean a 0-length "secret" input. */
    if( slen != 0 )
    {
        psa_key_attributes_t key_attributes = psa_key_attributes_init();
        psa_set_key_usage_flags( &key_attributes, PSA_KEY_USAGE_DERIVE );
        psa_set_key_algorithm( &key_attributes, alg );
        psa_set_key_type( &key_attributes, PSA_KEY_TYPE_DERIVE );

        status = psa_import_key( &key_attributes, secret, slen, &master_key );
        if( status != PSA_SUCCESS )
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
    }

    status = setup_psa_key_derivation( &derivation,
                                       master_key, alg,
                                       random, rlen,
                                       (unsigned char const *) label,
                                       (size_t) strlen( label ),
                                       dlen );
    if( status != PSA_SUCCESS )
    {
        psa_key_derivation_abort( &derivation );
        psa_destroy_key( master_key );
        return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
    }

    status = psa_key_derivation_output_bytes( &derivation, dstbuf, dlen );
    if( status != PSA_SUCCESS )
    {
        psa_key_derivation_abort( &derivation );
        psa_destroy_key( master_key );
        return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
    }

    status = psa_key_derivation_abort( &derivation );
    if( status != PSA_SUCCESS )
    {
        psa_destroy_key( master_key );
        return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
    }

    if( ! mbedtls_svc_key_id_is_null( master_key ) )
        status = psa_destroy_key( master_key );
    if( status != PSA_SUCCESS )
        return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );

    return( 0 );
}

#else /* MBEDTLS_USE_PSA_CRYPTO */

static int tls_prf_generic( mbedtls_md_type_t md_type,
                            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, md_len;
    unsigned char *tmp;
    size_t tmp_len = 0;
    unsigned char h_i[MBEDTLS_MD_MAX_SIZE];
    const mbedtls_md_info_t *md_info;
    mbedtls_md_context_t md_ctx;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    mbedtls_md_init( &md_ctx );

    if( ( md_info = mbedtls_md_info_from_type( md_type ) ) == NULL )
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );

    md_len = mbedtls_md_get_size( md_info );

    tmp_len = md_len + strlen( label ) + rlen;
    tmp = mbedtls_calloc( 1, tmp_len );
    if( tmp == NULL )
    {
        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
        goto exit;
    }

    nb = strlen( label );
    memcpy( tmp + md_len, label, nb );
    memcpy( tmp + md_len + nb, random, rlen );
    nb += rlen;

    /*
     * Compute P_<hash>(secret, label + random)[0..dlen]
     */
    if ( ( ret = mbedtls_md_setup( &md_ctx, md_info, 1 ) ) != 0 )
        goto exit;

    ret = mbedtls_md_hmac_starts( &md_ctx, secret, slen );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_update( &md_ctx, tmp + md_len, nb );
    if( ret != 0 )
        goto exit;
    ret = mbedtls_md_hmac_finish( &md_ctx, tmp );
    if( ret != 0 )
        goto exit;

    for( i = 0; i < dlen; i += md_len )
    {
        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, tmp, md_len + nb );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, h_i );
        if( ret != 0 )
            goto exit;

        ret = mbedtls_md_hmac_reset ( &md_ctx );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_update( &md_ctx, tmp, md_len );
        if( ret != 0 )
            goto exit;
        ret = mbedtls_md_hmac_finish( &md_ctx, tmp );
        if( ret != 0 )
            goto exit;

        k = ( i + md_len > dlen ) ? dlen % md_len : md_len;

        for( j = 0; j < k; j++ )
            dstbuf[i + j]  = h_i[j];
    }

exit:
    mbedtls_md_free( &md_ctx );

    mbedtls_platform_zeroize( tmp, tmp_len );
    mbedtls_platform_zeroize( h_i, sizeof( h_i ) );

    mbedtls_free( tmp );

    return( ret );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_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 )
{
    return( tls_prf_generic( MBEDTLS_MD_SHA256, secret, slen,
                             label, random, rlen, dstbuf, dlen ) );
}
#endif /* MBEDTLS_SHA256_C */

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
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 )
{
    return( tls_prf_generic( MBEDTLS_MD_SHA384, secret, slen,
                             label, random, rlen, dstbuf, dlen ) );
}
#endif /* MBEDTLS_SHA512_C && !MBEDTLS_SHA512_NO_SHA384 */
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

static void ssl_update_checksum_start( mbedtls_ssl_context *, const unsigned char *, size_t );

#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
static void ssl_update_checksum_md5sha1( mbedtls_ssl_context *, const unsigned char *, size_t );
#endif

#if defined(MBEDTLS_SSL_PROTO_SSL3)
static void ssl_calc_verify_ssl( const mbedtls_ssl_context *, unsigned char *, size_t * );
static void ssl_calc_finished_ssl( mbedtls_ssl_context *, unsigned char *, int );
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
static void ssl_calc_verify_tls( const mbedtls_ssl_context *, unsigned char*, size_t * );
static void ssl_calc_finished_tls( mbedtls_ssl_context *, unsigned char *, int );
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
static void ssl_update_checksum_sha256( mbedtls_ssl_context *, const unsigned char *, size_t );
static void ssl_calc_verify_tls_sha256( const mbedtls_ssl_context *,unsigned char*, size_t * );
static void ssl_calc_finished_tls_sha256( mbedtls_ssl_context *,unsigned char *, int );
#endif

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
static void ssl_update_checksum_sha384( mbedtls_ssl_context *, const unsigned char *, size_t );
static void ssl_calc_verify_tls_sha384( const mbedtls_ssl_context *, unsigned char*, size_t * );
static void ssl_calc_finished_tls_sha384( mbedtls_ssl_context *, unsigned char *, int );
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

#if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) && \
    defined(MBEDTLS_USE_PSA_CRYPTO)
static int ssl_use_opaque_psk( mbedtls_ssl_context const *ssl )
{
    if( ssl->conf->f_psk != NULL )
    {
        /* If we've used a callback to select the PSK,
         * the static configuration is irrelevant. */
        if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
            return( 1 );

        return( 0 );
    }

    if( ! mbedtls_svc_key_id_is_null( ssl->conf->psk_opaque ) )
        return( 1 );

    return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO &&
          MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */

#if defined(MBEDTLS_SSL_EXPORT_KEYS)
static mbedtls_tls_prf_types tls_prf_get_type( mbedtls_ssl_tls_prf_cb *tls_prf )
{
#if defined(MBEDTLS_SSL_PROTO_SSL3)
    if( tls_prf == ssl3_prf )
    {
        return( MBEDTLS_SSL_TLS_PRF_SSL3 );
    }
    else
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
    if( tls_prf == tls1_prf )
    {
        return( MBEDTLS_SSL_TLS_PRF_TLS1 );
    }
    else
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
    if( tls_prf == tls_prf_sha384 )
    {
        return( MBEDTLS_SSL_TLS_PRF_SHA384 );
    }
    else
#endif
#if defined(MBEDTLS_SHA256_C)
    if( tls_prf == tls_prf_sha256 )
    {
        return( MBEDTLS_SSL_TLS_PRF_SHA256 );
    }
    else
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
    return( MBEDTLS_SSL_TLS_PRF_NONE );
}
#endif /* MBEDTLS_SSL_EXPORT_KEYS */

int  mbedtls_ssl_tls_prf( const mbedtls_tls_prf_types prf,
                          const unsigned char *secret, size_t slen,
                          const char *label,
                          const unsigned char *random, size_t rlen,
                          unsigned char *dstbuf, size_t dlen )
{
    mbedtls_ssl_tls_prf_cb *tls_prf = NULL;

    switch( prf )
    {
#if defined(MBEDTLS_SSL_PROTO_SSL3)
        case MBEDTLS_SSL_TLS_PRF_SSL3:
            tls_prf = ssl3_prf;
        break;
#endif /* MBEDTLS_SSL_PROTO_SSL3 */
#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
        case MBEDTLS_SSL_TLS_PRF_TLS1:
            tls_prf = tls1_prf;
        break;
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 */

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
        case MBEDTLS_SSL_TLS_PRF_SHA384:
            tls_prf = tls_prf_sha384;
        break;
#endif /* MBEDTLS_SHA512_C && !MBEDTLS_SHA512_NO_SHA384 */
#if defined(MBEDTLS_SHA256_C)
        case MBEDTLS_SSL_TLS_PRF_SHA256:
            tls_prf = tls_prf_sha256;
        break;
#endif /* MBEDTLS_SHA256_C */
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
    default:
        return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
    }

    return( tls_prf( secret, slen, label, random, rlen, dstbuf, dlen ) );
}

/* Type for the TLS PRF */
typedef int ssl_tls_prf_t(const unsigned char *, size_t, const char *,
                          const unsigned char *, size_t,
                          unsigned char *, size_t);

/*
 * Populate a transform structure with session keys and all the other
 * necessary information.
 *
 * Parameters:
 * - [in/out]: transform: structure to populate
 *      [in] must be just initialised with mbedtls_ssl_transform_init()
 *      [out] fully populated, ready for use by mbedtls_ssl_{en,de}crypt_buf()
 * - [in] ciphersuite
 * - [in] master
 * - [in] encrypt_then_mac
 * - [in] trunc_hmac
 * - [in] compression
 * - [in] tls_prf: pointer to PRF to use for key derivation
 * - [in] randbytes: buffer holding ServerHello.random + ClientHello.random
 * - [in] minor_ver: SSL/TLS minor version
 * - [in] endpoint: client or server
 * - [in] ssl: optionally used for:
 *        - MBEDTLS_SSL_HW_RECORD_ACCEL: whole context (non-const)
 *        - MBEDTLS_SSL_EXPORT_KEYS: ssl->conf->{f,p}_export_keys
 *        - MBEDTLS_DEBUG_C: ssl->conf->{f,p}_dbg
 */
static int ssl_populate_transform( mbedtls_ssl_transform *transform,
                                   int ciphersuite,
                                   const unsigned char master[48],
#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
                                   int encrypt_then_mac,
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
                                   int trunc_hmac,
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */
#if defined(MBEDTLS_ZLIB_SUPPORT)
                                   int compression,
#endif
                                   ssl_tls_prf_t tls_prf,
                                   const unsigned char randbytes[64],
                                   int minor_ver,
                                   unsigned endpoint,
#if !defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
                                   const
#endif
                                   mbedtls_ssl_context *ssl )
{
    int ret = 0;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    int psa_fallthrough;
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    unsigned char keyblk[256];
    unsigned char *key1;
    unsigned char *key2;
    unsigned char *mac_enc;
    unsigned char *mac_dec;
    size_t mac_key_len = 0;
    size_t iv_copy_len;
    unsigned keylen;
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
    const mbedtls_cipher_info_t *cipher_info;
    const mbedtls_md_info_t *md_info;

#if !defined(MBEDTLS_SSL_HW_RECORD_ACCEL) && \
    !defined(MBEDTLS_SSL_EXPORT_KEYS) && \
    !defined(MBEDTLS_DEBUG_C)
    ssl = NULL; /* make sure we don't use it except for those cases */
    (void) ssl;
#endif

    /*
     * Some data just needs copying into the structure
     */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) && \
    defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
    transform->encrypt_then_mac = encrypt_then_mac;
#endif
    transform->minor_ver = minor_ver;

#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
    memcpy( transform->randbytes, randbytes, sizeof( transform->randbytes ) );
#endif

    /*
     * Get various info structures
     */
    ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuite );
    if( ciphersuite_info == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "ciphersuite info for %d not found",
                                    ciphersuite ) );
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    cipher_info = mbedtls_cipher_info_from_type( ciphersuite_info->cipher );
    if( cipher_info == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "cipher info for %u not found",
                                    ciphersuite_info->cipher ) );
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    md_info = mbedtls_md_info_from_type( ciphersuite_info->mac );
    if( md_info == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "mbedtls_md info for %u not found",
                            (unsigned) ciphersuite_info->mac ) );
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    /* Copy own and peer's CID if the use of the CID
     * extension has been negotiated. */
    if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_ENABLED )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Copy CIDs into SSL transform" ) );

        transform->in_cid_len = ssl->own_cid_len;
        memcpy( transform->in_cid, ssl->own_cid, ssl->own_cid_len );
        MBEDTLS_SSL_DEBUG_BUF( 3, "Incoming CID", transform->in_cid,
                               transform->in_cid_len );

        transform->out_cid_len = ssl->handshake->peer_cid_len;
        memcpy( transform->out_cid, ssl->handshake->peer_cid,
                ssl->handshake->peer_cid_len );
        MBEDTLS_SSL_DEBUG_BUF( 3, "Outgoing CID", transform->out_cid,
                               transform->out_cid_len );
    }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

    /*
     * Compute key block using the PRF
     */
    ret = tls_prf( master, 48, "key expansion", randbytes, 64, keyblk, 256 );
    if( ret != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "prf", ret );
        return( ret );
    }

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite = %s",
                           mbedtls_ssl_get_ciphersuite_name( ciphersuite ) ) );
    MBEDTLS_SSL_DEBUG_BUF( 3, "master secret", master, 48 );
    MBEDTLS_SSL_DEBUG_BUF( 4, "random bytes", randbytes, 64 );
    MBEDTLS_SSL_DEBUG_BUF( 4, "key block", keyblk, 256 );

    /*
     * Determine the appropriate key, IV and MAC length.
     */

    keylen = cipher_info->key_bitlen / 8;

#if defined(MBEDTLS_GCM_C) ||                           \
    defined(MBEDTLS_CCM_C) ||                           \
    defined(MBEDTLS_CHACHAPOLY_C)
    if( cipher_info->mode == MBEDTLS_MODE_GCM ||
        cipher_info->mode == MBEDTLS_MODE_CCM ||
        cipher_info->mode == MBEDTLS_MODE_CHACHAPOLY )
    {
        size_t explicit_ivlen;

        transform->maclen = 0;
        mac_key_len = 0;
        transform->taglen =
            ciphersuite_info->flags & MBEDTLS_CIPHERSUITE_SHORT_TAG ? 8 : 16;

        /* All modes haves 96-bit IVs, but the length of the static parts vary
         * with mode and version:
         * - For GCM and CCM in TLS 1.2, there's a static IV of 4 Bytes
         *   (to be concatenated with a dynamically chosen IV of 8 Bytes)
         * - For ChaChaPoly in TLS 1.2, and all modes in TLS 1.3, there's
         *   a static IV of 12 Bytes (to be XOR'ed with the 8 Byte record
         *   sequence number).
         */
        transform->ivlen = 12;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
        if( minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 )
        {
            transform->fixed_ivlen = 12;
        }
        else
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
        {
            if( cipher_info->mode == MBEDTLS_MODE_CHACHAPOLY )
                transform->fixed_ivlen = 12;
            else
                transform->fixed_ivlen = 4;
        }

        /* Minimum length of encrypted record */
        explicit_ivlen = transform->ivlen - transform->fixed_ivlen;
        transform->minlen = explicit_ivlen + transform->taglen;
    }
    else
#endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C || MBEDTLS_CHACHAPOLY_C */
#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
    if( cipher_info->mode == MBEDTLS_MODE_STREAM ||
        cipher_info->mode == MBEDTLS_MODE_CBC )
    {
        /* Initialize HMAC contexts */
        if( ( ret = mbedtls_md_setup( &transform->md_ctx_enc, md_info, 1 ) ) != 0 ||
            ( ret = mbedtls_md_setup( &transform->md_ctx_dec, md_info, 1 ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret );
            goto end;
        }

        /* Get MAC length */
        mac_key_len = mbedtls_md_get_size( md_info );
        transform->maclen = mac_key_len;

#if defined(MBEDTLS_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( trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED )
        {
            transform->maclen = MBEDTLS_SSL_TRUNCATED_HMAC_LEN;

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT)
            /* Fall back to old, non-compliant version of the truncated
             * HMAC implementation which also truncates the key
             * (Mbed TLS versions from 1.3 to 2.6.0) */
            mac_key_len = transform->maclen;
#endif
        }
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */

        /* IV length */
        transform->ivlen = cipher_info->iv_size;

        /* Minimum length */
        if( cipher_info->mode == MBEDTLS_MODE_STREAM )
            transform->minlen = transform->maclen;
        else
        {
            /*
             * GenericBlockCipher:
             * 1. if EtM is in use: one block plus MAC
             *    otherwise: * first multiple of blocklen greater than maclen
             * 2. IV except for SSL3 and TLS 1.0
             */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
            if( encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED )
            {
                transform->minlen = transform->maclen
                                  + cipher_info->block_size;
            }
            else
#endif
            {
                transform->minlen = transform->maclen
                                  + cipher_info->block_size
                                  - transform->maclen % cipher_info->block_size;
            }

#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1)
            if( minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ||
                minor_ver == MBEDTLS_SSL_MINOR_VERSION_1 )
                ; /* No need to adjust minlen */
            else
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2)
            if( minor_ver == MBEDTLS_SSL_MINOR_VERSION_2 ||
                minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
            {
                transform->minlen += transform->ivlen;
            }
            else
#endif
            {
                MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
                ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
                goto end;
            }
        }
    }
    else
#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
    }

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "keylen: %u, minlen: %u, ivlen: %u, maclen: %u",
                                (unsigned) keylen,
                                (unsigned) transform->minlen,
                                (unsigned) transform->ivlen,
                                (unsigned) transform->maclen ) );

    /*
     * Finally setup the cipher contexts, IVs and MAC secrets.
     */
#if defined(MBEDTLS_SSL_CLI_C)
    if( endpoint == MBEDTLS_SSL_IS_CLIENT )
    {
        key1 = keyblk + mac_key_len * 2;
        key2 = keyblk + mac_key_len * 2 + keylen;

        mac_enc = keyblk;
        mac_dec = keyblk + mac_key_len;

        /*
         * This is not used in TLS v1.1.
         */
        iv_copy_len = ( transform->fixed_ivlen ) ?
                            transform->fixed_ivlen : transform->ivlen;
        memcpy( transform->iv_enc, key2 + keylen,  iv_copy_len );
        memcpy( transform->iv_dec, key2 + keylen + iv_copy_len,
                iv_copy_len );
    }
    else
#endif /* MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SRV_C)
    if( endpoint == MBEDTLS_SSL_IS_SERVER )
    {
        key1 = keyblk + mac_key_len * 2 + keylen;
        key2 = keyblk + mac_key_len * 2;

        mac_enc = keyblk + mac_key_len;
        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 + keylen,  iv_copy_len );
        memcpy( transform->iv_enc, key1 + keylen + iv_copy_len,
                iv_copy_len );
    }
    else
#endif /* MBEDTLS_SSL_SRV_C */
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
        goto end;
    }

#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
#if defined(MBEDTLS_SSL_PROTO_SSL3)
    if( minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
    {
        if( mac_key_len > sizeof( transform->mac_enc ) )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
            ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
            goto end;
        }

        memcpy( transform->mac_enc, mac_enc, mac_key_len );
        memcpy( transform->mac_dec, mac_dec, mac_key_len );
    }
    else
#endif /* MBEDTLS_SSL_PROTO_SSL3 */
#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_2)
    if( minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 )
    {
        /* For HMAC-based ciphersuites, initialize the HMAC transforms.
           For AEAD-based ciphersuites, there is nothing to do here. */
        if( mac_key_len != 0 )
        {
            ret = mbedtls_md_hmac_starts( &transform->md_ctx_enc,
                                          mac_enc, mac_key_len );
            if( ret != 0 )
                goto end;
            ret = mbedtls_md_hmac_starts( &transform->md_ctx_dec,
                                          mac_dec, mac_key_len );
            if( ret != 0 )
                goto end;
        }
    }
    else
#endif
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
        goto end;
    }
#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */

#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
    if( mbedtls_ssl_hw_record_init != NULL )
    {
        ret = 0;

        MBEDTLS_SSL_DEBUG_MSG( 2, ( "going for mbedtls_ssl_hw_record_init()" ) );

        if( ( ret = mbedtls_ssl_hw_record_init( ssl, key1, key2, keylen,
                                        transform->iv_enc, transform->iv_dec,
                                        iv_copy_len,
                                        mac_enc, mac_dec,
                                        mac_key_len ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_init", ret );
            ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;
            goto end;
        }
    }
#else
    ((void) mac_dec);
    ((void) mac_enc);
#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */

#if defined(MBEDTLS_SSL_EXPORT_KEYS)
    if( ssl->conf->f_export_keys != NULL )
    {
        ssl->conf->f_export_keys( ssl->conf->p_export_keys,
                                  master, keyblk,
                                  mac_key_len, keylen,
                                  iv_copy_len );
    }

    if( ssl->conf->f_export_keys_ext != NULL )
    {
        ssl->conf->f_export_keys_ext( ssl->conf->p_export_keys,
                                      master, keyblk,
                                      mac_key_len, keylen,
                                      iv_copy_len,
                                      randbytes + 32,
                                      randbytes,
                                      tls_prf_get_type( tls_prf ) );
    }
#endif

#if defined(MBEDTLS_USE_PSA_CRYPTO)

    /* Only use PSA-based ciphers for TLS-1.2.
     * That's relevant at least for TLS-1.0, where
     * we assume that mbedtls_cipher_crypt() updates
     * the structure field for the IV, which the PSA-based
     * implementation currently doesn't. */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
    if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
    {
        ret = mbedtls_cipher_setup_psa( &transform->cipher_ctx_enc,
                                        cipher_info, transform->taglen );
        if( ret != 0 && ret != MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setup_psa", ret );
            goto end;
        }

        if( ret == 0 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Successfully setup PSA-based encryption cipher context" ) );
            psa_fallthrough = 0;
        }
        else
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "Failed to setup PSA-based cipher context for record encryption - fall through to default setup." ) );
            psa_fallthrough = 1;
        }
    }
    else
        psa_fallthrough = 1;
#else
    psa_fallthrough = 1;
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

    if( psa_fallthrough == 1 )
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    if( ( ret = mbedtls_cipher_setup( &transform->cipher_ctx_enc,
                                 cipher_info ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setup", ret );
        goto end;
    }

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    /* Only use PSA-based ciphers for TLS-1.2.
     * That's relevant at least for TLS-1.0, where
     * we assume that mbedtls_cipher_crypt() updates
     * the structure field for the IV, which the PSA-based
     * implementation currently doesn't. */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
    if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
    {
        ret = mbedtls_cipher_setup_psa( &transform->cipher_ctx_dec,
                                        cipher_info, transform->taglen );
        if( ret != 0 && ret != MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setup_psa", ret );
            goto end;
        }

        if( ret == 0 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Successfully setup PSA-based decryption cipher context" ) );
            psa_fallthrough = 0;
        }
        else
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "Failed to setup PSA-based cipher context for record decryption - fall through to default setup." ) );
            psa_fallthrough = 1;
        }
    }
    else
        psa_fallthrough = 1;
#else
    psa_fallthrough = 1;
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

    if( psa_fallthrough == 1 )
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    if( ( ret = mbedtls_cipher_setup( &transform->cipher_ctx_dec,
                                 cipher_info ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setup", ret );
        goto end;
    }

    if( ( ret = mbedtls_cipher_setkey( &transform->cipher_ctx_enc, key1,
                               cipher_info->key_bitlen,
                               MBEDTLS_ENCRYPT ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setkey", ret );
        goto end;
    }

    if( ( ret = mbedtls_cipher_setkey( &transform->cipher_ctx_dec, key2,
                               cipher_info->key_bitlen,
                               MBEDTLS_DECRYPT ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_setkey", ret );
        goto end;
    }

#if defined(MBEDTLS_CIPHER_MODE_CBC)
    if( cipher_info->mode == MBEDTLS_MODE_CBC )
    {
        if( ( ret = mbedtls_cipher_set_padding_mode( &transform->cipher_ctx_enc,
                                             MBEDTLS_PADDING_NONE ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_set_padding_mode", ret );
            goto end;
        }

        if( ( ret = mbedtls_cipher_set_padding_mode( &transform->cipher_ctx_dec,
                                             MBEDTLS_PADDING_NONE ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_set_padding_mode", ret );
            goto end;
        }
    }
#endif /* MBEDTLS_CIPHER_MODE_CBC */


    /* Initialize Zlib contexts */
#if defined(MBEDTLS_ZLIB_SUPPORT)
    if( compression == MBEDTLS_SSL_COMPRESS_DEFLATE )
    {
        MBEDTLS_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 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "Failed to initialize compression" ) );
            ret = MBEDTLS_ERR_SSL_COMPRESSION_FAILED;
            goto end;
        }
    }
#endif /* MBEDTLS_ZLIB_SUPPORT */

end:
    mbedtls_platform_zeroize( keyblk, sizeof( keyblk ) );
    return( ret );
}

/*
 * Set appropriate PRF function and other SSL / TLS 1.0/1.1 / TLS1.2 functions
 *
 * Inputs:
 * - SSL/TLS minor version
 * - hash associated with the ciphersuite (only used by TLS 1.2)
 *
 * Outputs:
 * - the tls_prf, calc_verify and calc_finished members of handshake structure
 */
static int ssl_set_handshake_prfs( mbedtls_ssl_handshake_params *handshake,
                                   int minor_ver,
                                   mbedtls_md_type_t hash )
{
#if !defined(MBEDTLS_SSL_PROTO_TLS1_2) ||       \
    !( defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384) )
    (void) hash;
#endif

#if defined(MBEDTLS_SSL_PROTO_SSL3)
    if( minor_ver == MBEDTLS_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(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
    if( minor_ver < MBEDTLS_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(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
    if( minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 &&
        hash == MBEDTLS_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(MBEDTLS_SHA256_C)
    if( minor_ver == MBEDTLS_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 /* MBEDTLS_SSL_PROTO_TLS1_2 */
    {
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
    }

    return( 0 );
}

/*
 * Compute master secret if needed
 *
 * Parameters:
 * [in/out] handshake
 *          [in] resume, premaster, extended_ms, calc_verify, tls_prf
 *               (PSA-PSK) ciphersuite_info, psk_opaque
 *          [out] premaster (cleared)
 * [out] master
 * [in] ssl: optionally used for debugging, EMS and PSA-PSK
 *      debug: conf->f_dbg, conf->p_dbg
 *      EMS: passed to calc_verify (debug + (SSL3) session_negotiate)
 *      PSA-PSA: minor_ver, conf
 */
static int ssl_compute_master( mbedtls_ssl_handshake_params *handshake,
                               unsigned char *master,
                               const mbedtls_ssl_context *ssl )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    /* cf. RFC 5246, Section 8.1:
     * "The master secret is always exactly 48 bytes in length." */
    size_t const master_secret_len = 48;

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
    unsigned char session_hash[48];
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */

    /* The label for the KDF used for key expansion.
     * This is either "master secret" or "extended master secret"
     * depending on whether the Extended Master Secret extension
     * is used. */
    char const *lbl = "master secret";

    /* The salt for the KDF used for key expansion.
     * - If the Extended Master Secret extension is not used,
     *   this is ClientHello.Random + ServerHello.Random
     *   (see Sect. 8.1 in RFC 5246).
     * - If the Extended Master Secret extension is used,
     *   this is the transcript of the handshake so far.
     *   (see Sect. 4 in RFC 7627). */
    unsigned char const *salt = handshake->randbytes;
    size_t salt_len = 64;

#if !defined(MBEDTLS_DEBUG_C) &&                    \
    !defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) && \
    !(defined(MBEDTLS_USE_PSA_CRYPTO) &&            \
      defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED))
    ssl = NULL; /* make sure we don't use it except for those cases */
    (void) ssl;
#endif

    if( handshake->resume != 0 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "no premaster (session resumed)" ) );
        return( 0 );
    }

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
    if( handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED )
    {
        lbl  = "extended master secret";
        salt = session_hash;
        handshake->calc_verify( ssl, session_hash, &salt_len );

        MBEDTLS_SSL_DEBUG_BUF( 3, "session hash for extended master secret",
                                  session_hash, salt_len );
    }
#endif /* MBEDTLS_SSL_EXTENDED_MS_ENABLED */

#if defined(MBEDTLS_USE_PSA_CRYPTO) &&          \
    defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
    if( handshake->ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK &&
        ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 &&
        ssl_use_opaque_psk( ssl ) == 1 )
    {
        /* Perform PSK-to-MS expansion in a single step. */
        psa_status_t status;
        psa_algorithm_t alg;
        psa_key_id_t psk;
        psa_key_derivation_operation_t derivation =
            PSA_KEY_DERIVATION_OPERATION_INIT;
        mbedtls_md_type_t hash_alg = handshake->ciphersuite_info->mac;

        MBEDTLS_SSL_DEBUG_MSG( 2, ( "perform PSA-based PSK-to-MS expansion" ) );

        psk = mbedtls_ssl_get_opaque_psk( ssl );

        if( hash_alg == MBEDTLS_MD_SHA384 )
            alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384);
        else
            alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256);

        status = setup_psa_key_derivation( &derivation, psk, alg,
                                           salt, salt_len,
                                           (unsigned char const *) lbl,
                                           (size_t) strlen( lbl ),
                                           master_secret_len );
        if( status != PSA_SUCCESS )
        {
            psa_key_derivation_abort( &derivation );
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
        }

        status = psa_key_derivation_output_bytes( &derivation,
                                                  master,
                                                  master_secret_len );
        if( status != PSA_SUCCESS )
        {
            psa_key_derivation_abort( &derivation );
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
        }

        status = psa_key_derivation_abort( &derivation );
        if( status != PSA_SUCCESS )
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
    }
    else
#endif
    {
        ret = handshake->tls_prf( handshake->premaster, handshake->pmslen,
                                  lbl, salt, salt_len,
                                  master,
                                  master_secret_len );
        if( ret != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "prf", ret );
            return( ret );
        }

        MBEDTLS_SSL_DEBUG_BUF( 3, "premaster secret",
                               handshake->premaster,
                               handshake->pmslen );

        mbedtls_platform_zeroize( handshake->premaster,
                                  sizeof(handshake->premaster) );
    }

    return( 0 );
}

int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    const mbedtls_ssl_ciphersuite_t * const ciphersuite_info =
        ssl->handshake->ciphersuite_info;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> derive keys" ) );

    /* Set PRF, calc_verify and calc_finished function pointers */
    ret = ssl_set_handshake_prfs( ssl->handshake,
                                  ssl->minor_ver,
                                  ciphersuite_info->mac );
    if( ret != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "ssl_set_handshake_prfs", ret );
        return( ret );
    }

    /* Compute master secret if needed */
    ret = ssl_compute_master( ssl->handshake,
                              ssl->session_negotiate->master,
                              ssl );
    if( ret != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "ssl_compute_master", ret );
        return( ret );
    }

    /* Swap the client and server random values:
     * - MS derivation wanted client+server (RFC 5246 8.1)
     * - key derivation wants server+client (RFC 5246 6.3) */
    {
        unsigned char tmp[64];
        memcpy( tmp, ssl->handshake->randbytes, 64 );
        memcpy( ssl->handshake->randbytes, tmp + 32, 32 );
        memcpy( ssl->handshake->randbytes + 32, tmp, 32 );
        mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
    }

    /* Populate transform structure */
    ret = ssl_populate_transform( ssl->transform_negotiate,
                                  ssl->session_negotiate->ciphersuite,
                                  ssl->session_negotiate->master,
#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
                                  ssl->session_negotiate->encrypt_then_mac,
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
                                  ssl->session_negotiate->trunc_hmac,
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */
#if defined(MBEDTLS_ZLIB_SUPPORT)
                                  ssl->session_negotiate->compression,
#endif
                                  ssl->handshake->tls_prf,
                                  ssl->handshake->randbytes,
                                  ssl->minor_ver,
                                  ssl->conf->endpoint,
                                  ssl );
    if( ret != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "ssl_populate_transform", ret );
        return( ret );
    }

    /* We no longer need Server/ClientHello.random values */
    mbedtls_platform_zeroize( ssl->handshake->randbytes,
                      sizeof( ssl->handshake->randbytes ) );

    /* Allocate compression buffer */
#if defined(MBEDTLS_ZLIB_SUPPORT)
    if( ssl->session_negotiate->compression == MBEDTLS_SSL_COMPRESS_DEFLATE &&
        ssl->compress_buf == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Allocating compression buffer" ) );
        ssl->compress_buf = mbedtls_calloc( 1, MBEDTLS_SSL_COMPRESS_BUFFER_LEN );
        if( ssl->compress_buf == NULL )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
                                        MBEDTLS_SSL_COMPRESS_BUFFER_LEN ) );
            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
        }
    }
#endif

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= derive keys" ) );

    return( 0 );
}

#if defined(MBEDTLS_SSL_PROTO_SSL3)
void ssl_calc_verify_ssl( const mbedtls_ssl_context *ssl,
                          unsigned char *hash,
                          size_t *hlen )
{
    mbedtls_md5_context md5;
    mbedtls_sha1_context sha1;
    unsigned char pad_1[48];
    unsigned char pad_2[48];

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify ssl" ) );

    mbedtls_md5_init( &md5 );
    mbedtls_sha1_init( &sha1 );

    mbedtls_md5_clone( &md5, &ssl->handshake->fin_md5 );
    mbedtls_sha1_clone( &sha1, &ssl->handshake->fin_sha1 );

    memset( pad_1, 0x36, 48 );
    memset( pad_2, 0x5C, 48 );

    mbedtls_md5_update_ret( &md5, ssl->session_negotiate->master, 48 );
    mbedtls_md5_update_ret( &md5, pad_1, 48 );
    mbedtls_md5_finish_ret( &md5, hash );

    mbedtls_md5_starts_ret( &md5 );
    mbedtls_md5_update_ret( &md5, ssl->session_negotiate->master, 48 );
    mbedtls_md5_update_ret( &md5, pad_2, 48 );
    mbedtls_md5_update_ret( &md5, hash,  16 );
    mbedtls_md5_finish_ret( &md5, hash );

    mbedtls_sha1_update_ret( &sha1, ssl->session_negotiate->master, 48 );
    mbedtls_sha1_update_ret( &sha1, pad_1, 40 );
    mbedtls_sha1_finish_ret( &sha1, hash + 16 );

    mbedtls_sha1_starts_ret( &sha1 );
    mbedtls_sha1_update_ret( &sha1, ssl->session_negotiate->master, 48 );
    mbedtls_sha1_update_ret( &sha1, pad_2, 40 );
    mbedtls_sha1_update_ret( &sha1, hash + 16, 20 );
    mbedtls_sha1_finish_ret( &sha1, hash + 16 );

    *hlen = 36;

    MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );

    mbedtls_md5_free(  &md5  );
    mbedtls_sha1_free( &sha1 );

    return;
}
#endif /* MBEDTLS_SSL_PROTO_SSL3 */

#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
void ssl_calc_verify_tls( const mbedtls_ssl_context *ssl,
                          unsigned char *hash,
                          size_t *hlen )
{
    mbedtls_md5_context md5;
    mbedtls_sha1_context sha1;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify tls" ) );

    mbedtls_md5_init( &md5 );
    mbedtls_sha1_init( &sha1 );

    mbedtls_md5_clone( &md5, &ssl->handshake->fin_md5 );
    mbedtls_sha1_clone( &sha1, &ssl->handshake->fin_sha1 );

    mbedtls_md5_finish_ret( &md5,  hash );
    mbedtls_sha1_finish_ret( &sha1, hash + 16 );

    *hlen = 36;

    MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );

    mbedtls_md5_free(  &md5  );
    mbedtls_sha1_free( &sha1 );

    return;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 */

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
void ssl_calc_verify_tls_sha256( const mbedtls_ssl_context *ssl,
                                 unsigned char *hash,
                                 size_t *hlen )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    size_t hash_size;
    psa_status_t status;
    psa_hash_operation_t sha256_psa = psa_hash_operation_init();

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> PSA calc verify sha256" ) );
    status = psa_hash_clone( &ssl->handshake->fin_sha256_psa, &sha256_psa );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash clone failed" ) );
        return;
    }

    status = psa_hash_finish( &sha256_psa, hash, 32, &hash_size );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash finish failed" ) );
        return;
    }

    *hlen = 32;
    MBEDTLS_SSL_DEBUG_BUF( 3, "PSA calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= PSA calc verify" ) );
#else
    mbedtls_sha256_context sha256;

    mbedtls_sha256_init( &sha256 );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify sha256" ) );

    mbedtls_sha256_clone( &sha256, &ssl->handshake->fin_sha256 );
    mbedtls_sha256_finish_ret( &sha256, hash );

    *hlen = 32;

    MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );

    mbedtls_sha256_free( &sha256 );
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    return;
}
#endif /* MBEDTLS_SHA256_C */

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
void ssl_calc_verify_tls_sha384( const mbedtls_ssl_context *ssl,
                                 unsigned char *hash,
                                 size_t *hlen )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    size_t hash_size;
    psa_status_t status;
    psa_hash_operation_t sha384_psa = psa_hash_operation_init();

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> PSA calc verify sha384" ) );
    status = psa_hash_clone( &ssl->handshake->fin_sha384_psa, &sha384_psa );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash clone failed" ) );
        return;
    }

    status = psa_hash_finish( &sha384_psa, hash, 48, &hash_size );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash finish failed" ) );
        return;
    }

    *hlen = 48;
    MBEDTLS_SSL_DEBUG_BUF( 3, "PSA calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= PSA calc verify" ) );
#else
    mbedtls_sha512_context sha512;

    mbedtls_sha512_init( &sha512 );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify sha384" ) );

    mbedtls_sha512_clone( &sha512, &ssl->handshake->fin_sha512 );
    mbedtls_sha512_finish_ret( &sha512, hash );

    *hlen = 48;

    MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, *hlen );
    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );

    mbedtls_sha512_free( &sha512 );
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    return;
}
#endif /* MBEDTLS_SHA512_C && !MBEDTLS_SHA512_NO_SHA384 */
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
int mbedtls_ssl_psk_derive_premaster( mbedtls_ssl_context *ssl, mbedtls_key_exchange_type_t key_ex )
{
    unsigned char *p = ssl->handshake->premaster;
    unsigned char *end = p + sizeof( ssl->handshake->premaster );
    const unsigned char *psk = NULL;
    size_t psk_len = 0;

    if( mbedtls_ssl_get_psk( ssl, &psk, &psk_len )
            == MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED )
    {
        /*
         * This should never happen because the existence of a PSK is always
         * checked before calling this function
         */
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
    }

    /*
     * 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(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
    if( key_ex == MBEDTLS_KEY_EXCHANGE_PSK )
    {
        if( end - p < 2 )
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

        MBEDTLS_PUT_UINT16_BE( psk_len, p, 0 );
        p += 2;

        if( end < p || (size_t)( end - p ) < psk_len )
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

        memset( p, 0, psk_len );
        p += psk_len;
    }
    else
#endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
    if( key_ex == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
    {
        /*
         * other_secret already set by the ClientKeyExchange message,
         * and is 48 bytes long
         */
        if( end - p < 2 )
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

        *p++ = 0;
        *p++ = 48;
        p += 48;
    }
    else
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
    if( key_ex == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
    {
        int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
        size_t len;

        /* Write length only when we know the actual value */
        if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
                                      p + 2, end - ( p + 2 ), &len,
                                      ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
            return( ret );
        }
        MBEDTLS_PUT_UINT16_BE( len, p, 0 );
        p += 2 + len;

        MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K  );
    }
    else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
    if( key_ex == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
    {
        int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
        size_t zlen;

        if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx, &zlen,
                                       p + 2, end - ( p + 2 ),
                                       ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
            return( ret );
        }

        MBEDTLS_PUT_UINT16_BE( zlen, p, 0 );
        p += 2 + zlen;

        MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
                                MBEDTLS_DEBUG_ECDH_Z );
    }
    else
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
    }

    /* opaque psk<0..2^16-1>; */
    if( end - p < 2 )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    MBEDTLS_PUT_UINT16_BE( psk_len, p, 0 );
    p += 2;

    if( end < p || (size_t)( end - p ) < psk_len )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    memcpy( p, psk, psk_len );
    p += psk_len;

    ssl->handshake->pmslen = p - ssl->handshake->premaster;

    return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */

#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_RENEGOTIATION)
static int ssl_write_hello_request( mbedtls_ssl_context *ssl );

#if defined(MBEDTLS_SSL_PROTO_DTLS)
int mbedtls_ssl_resend_hello_request( mbedtls_ssl_context *ssl )
{
    /* If renegotiation is not enforced, retransmit until we would reach max
     * timeout if we were using the usual handshake doubling scheme */
    if( ssl->conf->renego_max_records < 0 )
    {
        uint32_t ratio = ssl->conf->hs_timeout_max / ssl->conf->hs_timeout_min + 1;
        unsigned char doublings = 1;

        while( ratio != 0 )
        {
            ++doublings;
            ratio >>= 1;
        }

        if( ++ssl->renego_records_seen > doublings )
        {
            MBEDTLS_SSL_DEBUG_MSG( 2, ( "no longer retransmitting hello request" ) );
            return( 0 );
        }
    }

    return( ssl_write_hello_request( ssl ) );
}
#endif
#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_RENEGOTIATION */

#if defined(MBEDTLS_X509_CRT_PARSE_C)
static void ssl_clear_peer_cert( mbedtls_ssl_session *session )
{
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
    if( session->peer_cert != NULL )
    {
        mbedtls_x509_crt_free( session->peer_cert );
        mbedtls_free( session->peer_cert );
        session->peer_cert = NULL;
    }
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
    if( session->peer_cert_digest != NULL )
    {
        /* Zeroization is not necessary. */
        mbedtls_free( session->peer_cert_digest );
        session->peer_cert_digest      = NULL;
        session->peer_cert_digest_type = MBEDTLS_MD_NONE;
        session->peer_cert_digest_len  = 0;
    }
#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

/*
 * Handshake functions
 */
#if !defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* No certificate support -> dummy functions */
int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
{
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
        ssl->handshake->ciphersuite_info;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );

    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
        ssl->state++;
        return( 0 );
    }

    MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
    return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}

int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
{
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
        ssl->handshake->ciphersuite_info;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );

    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
        ssl->state++;
        return( 0 );
    }

    MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
    return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}

#else /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/* Some certificate support -> implement write and parse */

int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
{
    int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
    size_t i, n;
    const mbedtls_x509_crt *crt;
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
        ssl->handshake->ciphersuite_info;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );

    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
        ssl->state++;
        return( 0 );
    }

#if defined(MBEDTLS_SSL_CLI_C)
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
    {
        if( ssl->client_auth == 0 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
            ssl->state++;
            return( 0 );
        }

#if defined(MBEDTLS_SSL_PROTO_SSL3)
        /*
         * If using SSLv3 and got no cert, send an Alert message
         * (otherwise an empty Certificate message will be sent).
         */
        if( mbedtls_ssl_own_cert( ssl )  == NULL &&
            ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
        {
            ssl->out_msglen  = 2;
            ssl->out_msgtype = MBEDTLS_SSL_MSG_ALERT;
            ssl->out_msg[0]  = MBEDTLS_SSL_ALERT_LEVEL_WARNING;
            ssl->out_msg[1]  = MBEDTLS_SSL_ALERT_MSG_NO_CERT;

            MBEDTLS_SSL_DEBUG_MSG( 2, ( "got no certificate to send" ) );
            goto write_msg;
        }
#endif /* MBEDTLS_SSL_PROTO_SSL3 */
    }
#endif /* MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SRV_C)
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
    {
        if( mbedtls_ssl_own_cert( ssl ) == NULL )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no certificate to send" ) );
            return( MBEDTLS_ERR_SSL_CERTIFICATE_REQUIRED );
        }
    }
#endif

    MBEDTLS_SSL_DEBUG_CRT( 3, "own certificate", mbedtls_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 = mbedtls_ssl_own_cert( ssl );

    while( crt != NULL )
    {
        n = crt->raw.len;
        if( n > MBEDTLS_SSL_OUT_CONTENT_LEN - 3 - i )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "certificate too large, %" MBEDTLS_PRINTF_SIZET
                                        " > %" MBEDTLS_PRINTF_SIZET,
                           i + 3 + n, (size_t) MBEDTLS_SSL_OUT_CONTENT_LEN ) );
            return( MBEDTLS_ERR_SSL_CERTIFICATE_TOO_LARGE );
        }

        ssl->out_msg[i    ] = MBEDTLS_BYTE_2( n );
        ssl->out_msg[i + 1] = MBEDTLS_BYTE_1( n );
        ssl->out_msg[i + 2] = MBEDTLS_BYTE_0( n );

        i += 3; memcpy( ssl->out_msg + i, crt->raw.p, n );
        i += n; crt = crt->next;
    }

    ssl->out_msg[4]  = MBEDTLS_BYTE_2( i - 7 );
    ssl->out_msg[5]  = MBEDTLS_BYTE_1( i - 7 );
    ssl->out_msg[6]  = MBEDTLS_BYTE_0( i - 7 );

    ssl->out_msglen  = i;
    ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
    ssl->out_msg[0]  = MBEDTLS_SSL_HS_CERTIFICATE;

#if defined(MBEDTLS_SSL_PROTO_SSL3) && defined(MBEDTLS_SSL_CLI_C)
write_msg:
#endif

    ssl->state++;

    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
        return( ret );
    }

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate" ) );

    return( ret );
}

#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)

#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
                                         unsigned char *crt_buf,
                                         size_t crt_buf_len )
{
    mbedtls_x509_crt const * const peer_crt = ssl->session->peer_cert;

    if( peer_crt == NULL )
        return( -1 );

    if( peer_crt->raw.len != crt_buf_len )
        return( -1 );

    return( memcmp( peer_crt->raw.p, crt_buf, peer_crt->raw.len ) );
}
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
                                         unsigned char *crt_buf,
                                         size_t crt_buf_len )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char const * const peer_cert_digest =
        ssl->session->peer_cert_digest;
    mbedtls_md_type_t const peer_cert_digest_type =
        ssl->session->peer_cert_digest_type;
    mbedtls_md_info_t const * const digest_info =
        mbedtls_md_info_from_type( peer_cert_digest_type );
    unsigned char tmp_digest[MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN];
    size_t digest_len;

    if( peer_cert_digest == NULL || digest_info == NULL )
        return( -1 );

    digest_len = mbedtls_md_get_size( digest_info );
    if( digest_len > MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN )
        return( -1 );

    ret = mbedtls_md( digest_info, crt_buf, crt_buf_len, tmp_digest );
    if( ret != 0 )
        return( -1 );

    return( memcmp( tmp_digest, peer_cert_digest, digest_len ) );
}
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
#endif /* MBEDTLS_SSL_RENEGOTIATION && MBEDTLS_SSL_CLI_C */

/*
 * Once the certificate message is read, parse it into a cert chain and
 * perform basic checks, but leave actual verification to the caller
 */
static int ssl_parse_certificate_chain( mbedtls_ssl_context *ssl,
                                        mbedtls_x509_crt *chain )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
    int crt_cnt=0;
#endif
    size_t i, n;
    uint8_t alert;

    if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
        return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
    }

    if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE ||
        ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 3 + 3 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
        return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
    }

    i = mbedtls_ssl_hs_hdr_len( ssl );

    /*
     * Same message structure as in mbedtls_ssl_write_certificate()
     */
    n = ( ssl->in_msg[i+1] << 8 ) | ssl->in_msg[i+2];

    if( ssl->in_msg[i] != 0 ||
        ssl->in_hslen != n + 3 + mbedtls_ssl_hs_hdr_len( ssl ) )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
        return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
    }

    /* Make &ssl->in_msg[i] point to the beginning of the CRT chain. */
    i += 3;

    /* Iterate through and parse the CRTs in the provided chain. */
    while( i < ssl->in_hslen )
    {
        /* Check that there's room for the next CRT's length fields. */
        if ( i + 3 > ssl->in_hslen ) {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
            mbedtls_ssl_send_alert_message( ssl,
                              MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                              MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
        }
        /* In theory, the CRT can be up to 2**24 Bytes, but we don't support
         * anything beyond 2**16 ~ 64K. */
        if( ssl->in_msg[i] != 0 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
            mbedtls_ssl_send_alert_message( ssl,
                            MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
        }

        /* Read length of the next CRT in the chain. */
        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 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
            mbedtls_ssl_send_alert_message( ssl,
                                 MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                 MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
        }

        /* Check if we're handling the first CRT in the chain. */
#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
        if( crt_cnt++ == 0 &&
            ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
            ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
        {
            /* During client-side renegotiation, check that the server's
             * end-CRTs hasn't changed compared to the initial handshake,
             * mitigating the triple handshake attack. On success, reuse
             * the original end-CRT instead of parsing it again. */
            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Check that peer CRT hasn't changed during renegotiation" ) );
            if( ssl_check_peer_crt_unchanged( ssl,
                                              &ssl->in_msg[i],
                                              n ) != 0 )
            {
                MBEDTLS_SSL_DEBUG_MSG( 1, ( "new server cert during renegotiation" ) );
                mbedtls_ssl_send_alert_message( ssl,
                                                MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                                MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED );
                return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
            }

            /* Now we can safely free the original chain. */
            ssl_clear_peer_cert( ssl->session );
        }
#endif /* MBEDTLS_SSL_RENEGOTIATION && MBEDTLS_SSL_CLI_C */

        /* Parse the next certificate in the chain. */
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
        ret = mbedtls_x509_crt_parse_der( chain, ssl->in_msg + i, n );
#else
        /* If we don't need to store the CRT chain permanently, parse
         * it in-place from the input buffer instead of making a copy. */
        ret = mbedtls_x509_crt_parse_der_nocopy( chain, ssl->in_msg + i, n );
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
        switch( ret )
        {
            case 0: /*ok*/
            case MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND:
                /* Ignore certificate with an unknown algorithm: maybe a
                   prior certificate was already trusted. */
                break;

            case MBEDTLS_ERR_X509_ALLOC_FAILED:
                alert = MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR;
                goto crt_parse_der_failed;

            case MBEDTLS_ERR_X509_UNKNOWN_VERSION:
                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
                goto crt_parse_der_failed;

            default:
                alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
            crt_parse_der_failed:
                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, alert );
                MBEDTLS_SSL_DEBUG_RET( 1, " mbedtls_x509_crt_parse_der", ret );
                return( ret );
        }

        i += n;
    }

    MBEDTLS_SSL_DEBUG_CRT( 3, "peer certificate", chain );
    return( 0 );
}

#if defined(MBEDTLS_SSL_SRV_C)
static int ssl_srv_check_client_no_crt_notification( mbedtls_ssl_context *ssl )
{
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
        return( -1 );

#if defined(MBEDTLS_SSL_PROTO_SSL3)
    /*
     * Check if the client sent an empty certificate
     */
    if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
    {
        if( ssl->in_msglen  == 2                        &&
            ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT            &&
            ssl->in_msg[0]  == MBEDTLS_SSL_ALERT_LEVEL_WARNING  &&
            ssl->in_msg[1]  == MBEDTLS_SSL_ALERT_MSG_NO_CERT )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
            return( 0 );
        }

        return( -1 );
    }
#endif /* MBEDTLS_SSL_PROTO_SSL3 */

#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_2)
    if( ssl->in_hslen   == 3 + mbedtls_ssl_hs_hdr_len( ssl ) &&
        ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE    &&
        ssl->in_msg[0]  == MBEDTLS_SSL_HS_CERTIFICATE   &&
        memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
        return( 0 );
    }

    return( -1 );
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
          MBEDTLS_SSL_PROTO_TLS1_2 */
}
#endif /* MBEDTLS_SSL_SRV_C */

/* Check if a certificate message is expected.
 * Return either
 * - SSL_CERTIFICATE_EXPECTED, or
 * - SSL_CERTIFICATE_SKIP
 * indicating whether a Certificate message is expected or not.
 */
#define SSL_CERTIFICATE_EXPECTED 0
#define SSL_CERTIFICATE_SKIP     1
static int ssl_parse_certificate_coordinate( mbedtls_ssl_context *ssl,
                                             int authmode )
{
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
        ssl->handshake->ciphersuite_info;

    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
        return( SSL_CERTIFICATE_SKIP );

#if defined(MBEDTLS_SSL_SRV_C)
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
    {
        if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
            return( SSL_CERTIFICATE_SKIP );

        if( authmode == MBEDTLS_SSL_VERIFY_NONE )
        {
            ssl->session_negotiate->verify_result =
                MBEDTLS_X509_BADCERT_SKIP_VERIFY;
            return( SSL_CERTIFICATE_SKIP );
        }
    }
#else
    ((void) authmode);
#endif /* MBEDTLS_SSL_SRV_C */

    return( SSL_CERTIFICATE_EXPECTED );
}

static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl,
                                         int authmode,
                                         mbedtls_x509_crt *chain,
                                         void *rs_ctx )
{
    int ret = 0;
    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
        ssl->handshake->ciphersuite_info;
    int have_ca_chain = 0;

    int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *);
    void *p_vrfy;

    if( authmode == MBEDTLS_SSL_VERIFY_NONE )
        return( 0 );

    if( ssl->f_vrfy != NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use context-specific verification callback" ) );
        f_vrfy = ssl->f_vrfy;
        p_vrfy = ssl->p_vrfy;
    }
    else
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use configuration-specific verification callback" ) );
        f_vrfy = ssl->conf->f_vrfy;
        p_vrfy = ssl->conf->p_vrfy;
    }

    /*
     * Main check: verify certificate
     */
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
    if( ssl->conf->f_ca_cb != NULL )
    {
        ((void) rs_ctx);
        have_ca_chain = 1;

        MBEDTLS_SSL_DEBUG_MSG( 3, ( "use CA callback for X.509 CRT verification" ) );
        ret = mbedtls_x509_crt_verify_with_ca_cb(
            chain,
            ssl->conf->f_ca_cb,
            ssl->conf->p_ca_cb,
            ssl->conf->cert_profile,
            ssl->hostname,
            &ssl->session_negotiate->verify_result,
            f_vrfy, p_vrfy );
    }
    else
#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
    {
        mbedtls_x509_crt *ca_chain;
        mbedtls_x509_crl *ca_crl;

#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
        if( ssl->handshake->sni_ca_chain != NULL )
        {
            ca_chain = ssl->handshake->sni_ca_chain;
            ca_crl   = ssl->handshake->sni_ca_crl;
        }
        else
#endif
        {
            ca_chain = ssl->conf->ca_chain;
            ca_crl   = ssl->conf->ca_crl;
        }

        if( ca_chain != NULL )
            have_ca_chain = 1;

        ret = mbedtls_x509_crt_verify_restartable(
            chain,
            ca_chain, ca_crl,
            ssl->conf->cert_profile,
            ssl->hostname,
            &ssl->session_negotiate->verify_result,
            f_vrfy, p_vrfy, rs_ctx );
    }

    if( ret != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
    }

#if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
    if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
        return( MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS );
#endif

    /*
     * Secondary checks: always done, but change 'ret' only if it was 0
     */

#if defined(MBEDTLS_ECP_C)
    {
        const mbedtls_pk_context *pk = &chain->pk;

        /* If certificate uses an EC key, make sure the curve is OK */
        if( mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) &&
            mbedtls_ssl_check_curve( ssl, mbedtls_pk_ec( *pk )->grp.id ) != 0 )
        {
            ssl->session_negotiate->verify_result |= MBEDTLS_X509_BADCERT_BAD_KEY;

            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
            if( ret == 0 )
                ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
        }
    }
#endif /* MBEDTLS_ECP_C */

    if( mbedtls_ssl_check_cert_usage( chain,
                                      ciphersuite_info,
                                      ! ssl->conf->endpoint,
                                      &ssl->session_negotiate->verify_result ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (usage extensions)" ) );
        if( ret == 0 )
            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
    }

    /* mbedtls_x509_crt_verify_with_profile is supposed to report a
     * verification failure through MBEDTLS_ERR_X509_CERT_VERIFY_FAILED,
     * with details encoded in the verification flags. All other kinds
     * of error codes, including those from the user provided f_vrfy
     * functions, are treated as fatal and lead to a failure of
     * ssl_parse_certificate even if verification was optional. */
    if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
        ( ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
          ret == MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ) )
    {
        ret = 0;
    }

    if( have_ca_chain == 0 && authmode == MBEDTLS_SSL_VERIFY_REQUIRED )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
        ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
    }

    if( ret != 0 )
    {
        uint8_t alert;

        /* The certificate may have been rejected for several reasons.
           Pick one and send the corresponding alert. Which alert to send
           may be a subject of debate in some cases. */
        if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_OTHER )
            alert = MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH )
            alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_KEY_USAGE )
            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXT_KEY_USAGE )
            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NS_CERT_TYPE )
            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_PK )
            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_KEY )
            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXPIRED )
            alert = MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_REVOKED )
            alert = MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED;
        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED )
            alert = MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA;
        else
            alert = MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN;
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        alert );
    }

#if defined(MBEDTLS_DEBUG_C)
    if( ssl->session_negotiate->verify_result != 0 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "! Certificate verification flags %08x",
                                    (unsigned int) ssl->session_negotiate->verify_result ) );
    }
    else
    {
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Certificate verification flags clear" ) );
    }
#endif /* MBEDTLS_DEBUG_C */

    return( ret );
}

#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
static int ssl_remember_peer_crt_digest( mbedtls_ssl_context *ssl,
                                         unsigned char *start, size_t len )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    /* Remember digest of the peer's end-CRT. */
    ssl->session_negotiate->peer_cert_digest =
        mbedtls_calloc( 1, MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN );
    if( ssl->session_negotiate->peer_cert_digest == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
                                    MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN ) );
        mbedtls_ssl_send_alert_message( ssl,
                                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );

        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
    }

    ret = mbedtls_md( mbedtls_md_info_from_type(
                          MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE ),
                      start, len,
                      ssl->session_negotiate->peer_cert_digest );

    ssl->session_negotiate->peer_cert_digest_type =
        MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE;
    ssl->session_negotiate->peer_cert_digest_len =
        MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN;

    return( ret );
}

static int ssl_remember_peer_pubkey( mbedtls_ssl_context *ssl,
                                     unsigned char *start, size_t len )
{
    unsigned char *end = start + len;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    /* Make a copy of the peer's raw public key. */
    mbedtls_pk_init( &ssl->handshake->peer_pubkey );
    ret = mbedtls_pk_parse_subpubkey( &start, end,
                                      &ssl->handshake->peer_pubkey );
    if( ret != 0 )
    {
        /* We should have parsed the public key before. */
        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
    }

    return( 0 );
}
#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */

int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
{
    int ret = 0;
    int crt_expected;
#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
    const int authmode = ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET
                       ? ssl->handshake->sni_authmode
                       : ssl->conf->authmode;
#else
    const int authmode = ssl->conf->authmode;
#endif
    void *rs_ctx = NULL;
    mbedtls_x509_crt *chain = NULL;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );

    crt_expected = ssl_parse_certificate_coordinate( ssl, authmode );
    if( crt_expected == SSL_CERTIFICATE_SKIP )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
        goto exit;
    }

#if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
    if( ssl->handshake->ecrs_enabled &&
        ssl->handshake->ecrs_state == ssl_ecrs_crt_verify )
    {
        chain = ssl->handshake->ecrs_peer_cert;
        ssl->handshake->ecrs_peer_cert = NULL;
        goto crt_verify;
    }
#endif

    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
    {
        /* mbedtls_ssl_read_record may have sent an alert already. We
           let it decide whether to alert. */
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
        goto exit;
    }

#if defined(MBEDTLS_SSL_SRV_C)
    if( ssl_srv_check_client_no_crt_notification( ssl ) == 0 )
    {
        ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;

        if( authmode != MBEDTLS_SSL_VERIFY_OPTIONAL )
            ret = MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE;

        goto exit;
    }
#endif /* MBEDTLS_SSL_SRV_C */

    /* Clear existing peer CRT structure in case we tried to
     * reuse a session but it failed, and allocate a new one. */
    ssl_clear_peer_cert( ssl->session_negotiate );

    chain = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
    if( chain == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%" MBEDTLS_PRINTF_SIZET " bytes) failed",
                                    sizeof( mbedtls_x509_crt ) ) );
        mbedtls_ssl_send_alert_message( ssl,
                                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );

        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
        goto exit;
    }
    mbedtls_x509_crt_init( chain );

    ret = ssl_parse_certificate_chain( ssl, chain );
    if( ret != 0 )
        goto exit;

#if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
    if( ssl->handshake->ecrs_enabled)
        ssl->handshake->ecrs_state = ssl_ecrs_crt_verify;

crt_verify:
    if( ssl->handshake->ecrs_enabled)
        rs_ctx = &ssl->handshake->ecrs_ctx;
#endif

    ret = ssl_parse_certificate_verify( ssl, authmode,
                                        chain, rs_ctx );
    if( ret != 0 )
        goto exit;

#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
    {
        unsigned char *crt_start, *pk_start;
        size_t crt_len, pk_len;

        /* We parse the CRT chain without copying, so
         * these pointers point into the input buffer,
         * and are hence still valid after freeing the
         * CRT chain. */

        crt_start = chain->raw.p;
        crt_len   = chain->raw.len;

        pk_start = chain->pk_raw.p;
        pk_len   = chain->pk_raw.len;

        /* Free the CRT structures before computing
         * digest and copying the peer's public key. */
        mbedtls_x509_crt_free( chain );
        mbedtls_free( chain );
        chain = NULL;

        ret = ssl_remember_peer_crt_digest( ssl, crt_start, crt_len );
        if( ret != 0 )
            goto exit;

        ret = ssl_remember_peer_pubkey( ssl, pk_start, pk_len );
        if( ret != 0 )
            goto exit;
    }
#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
    /* Pass ownership to session structure. */
    ssl->session_negotiate->peer_cert = chain;
    chain = NULL;
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );

exit:

    if( ret == 0 )
        ssl->state++;

#if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
    if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
    {
        ssl->handshake->ecrs_peer_cert = chain;
        chain = NULL;
    }
#endif

    if( chain != NULL )
    {
        mbedtls_x509_crt_free( chain );
        mbedtls_free( chain );
    }

    return( ret );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */

void mbedtls_ssl_optimize_checksum( mbedtls_ssl_context *ssl,
                            const mbedtls_ssl_ciphersuite_t *ciphersuite_info )
{
    ((void) ciphersuite_info);

#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
    if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 )
        ssl->handshake->update_checksum = ssl_update_checksum_md5sha1;
    else
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
    if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
        ssl->handshake->update_checksum = ssl_update_checksum_sha384;
    else
#endif
#if defined(MBEDTLS_SHA256_C)
    if( ciphersuite_info->mac != MBEDTLS_MD_SHA384 )
        ssl->handshake->update_checksum = ssl_update_checksum_sha256;
    else
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
        return;
    }
}

void mbedtls_ssl_reset_checksum( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
     mbedtls_md5_starts_ret( &ssl->handshake->fin_md5  );
    mbedtls_sha1_starts_ret( &ssl->handshake->fin_sha1 );
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_abort( &ssl->handshake->fin_sha256_psa );
    psa_hash_setup( &ssl->handshake->fin_sha256_psa, PSA_ALG_SHA_256 );
#else
    mbedtls_sha256_starts_ret( &ssl->handshake->fin_sha256, 0 );
#endif
#endif
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_abort( &ssl->handshake->fin_sha384_psa );
    psa_hash_setup( &ssl->handshake->fin_sha384_psa, PSA_ALG_SHA_384 );
#else
    mbedtls_sha512_starts_ret( &ssl->handshake->fin_sha512, 1 );
#endif
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
}

static void ssl_update_checksum_start( mbedtls_ssl_context *ssl,
                                       const unsigned char *buf, size_t len )
{
#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
     mbedtls_md5_update_ret( &ssl->handshake->fin_md5 , buf, len );
    mbedtls_sha1_update_ret( &ssl->handshake->fin_sha1, buf, len );
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_update( &ssl->handshake->fin_sha256_psa, buf, len );
#else
    mbedtls_sha256_update_ret( &ssl->handshake->fin_sha256, buf, len );
#endif
#endif
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_update( &ssl->handshake->fin_sha384_psa, buf, len );
#else
    mbedtls_sha512_update_ret( &ssl->handshake->fin_sha512, buf, len );
#endif
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
}

#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
static void ssl_update_checksum_md5sha1( mbedtls_ssl_context *ssl,
                                         const unsigned char *buf, size_t len )
{
     mbedtls_md5_update_ret( &ssl->handshake->fin_md5 , buf, len );
    mbedtls_sha1_update_ret( &ssl->handshake->fin_sha1, buf, len );
}
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
static void ssl_update_checksum_sha256( mbedtls_ssl_context *ssl,
                                        const unsigned char *buf, size_t len )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_update( &ssl->handshake->fin_sha256_psa, buf, len );
#else
    mbedtls_sha256_update_ret( &ssl->handshake->fin_sha256, buf, len );
#endif
}
#endif

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
static void ssl_update_checksum_sha384( mbedtls_ssl_context *ssl,
                                        const unsigned char *buf, size_t len )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_hash_update( &ssl->handshake->fin_sha384_psa, buf, len );
#else
    mbedtls_sha512_update_ret( &ssl->handshake->fin_sha512, buf, len );
#endif
}
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

#if defined(MBEDTLS_SSL_PROTO_SSL3)
static void ssl_calc_finished_ssl(
                mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{
    const char *sender;
    mbedtls_md5_context  md5;
    mbedtls_sha1_context sha1;

    unsigned char padbuf[48];
    unsigned char md5sum[16];
    unsigned char sha1sum[20];

    mbedtls_ssl_session *session = ssl->session_negotiate;
    if( !session )
        session = ssl->session;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc  finished ssl" ) );

    mbedtls_md5_init( &md5 );
    mbedtls_sha1_init( &sha1 );

    mbedtls_md5_clone( &md5, &ssl->handshake->fin_md5 );
    mbedtls_sha1_clone( &sha1, &ssl->handshake->fin_sha1 );

    /*
     * SSLv3:
     *   hash =
     *      MD5( master + pad2 +
     *          MD5( handshake + sender + master + pad1 ) )
     *   + SHA1( master + pad2 +
     *         SHA1( handshake + sender + master + pad1 ) )
     */

#if !defined(MBEDTLS_MD5_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished  md5 state", (unsigned char *)
                    md5.state, sizeof(  md5.state ) );
#endif

#if !defined(MBEDTLS_SHA1_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha1 state", (unsigned char *)
                   sha1.state, sizeof( sha1.state ) );
#endif

    sender = ( from == MBEDTLS_SSL_IS_CLIENT ) ? "CLNT"
                                       : "SRVR";

    memset( padbuf, 0x36, 48 );

    mbedtls_md5_update_ret( &md5, (const unsigned char *) sender, 4 );
    mbedtls_md5_update_ret( &md5, session->master, 48 );
    mbedtls_md5_update_ret( &md5, padbuf, 48 );
    mbedtls_md5_finish_ret( &md5, md5sum );

    mbedtls_sha1_update_ret( &sha1, (const unsigned char *) sender, 4 );
    mbedtls_sha1_update_ret( &sha1, session->master, 48 );
    mbedtls_sha1_update_ret( &sha1, padbuf, 40 );
    mbedtls_sha1_finish_ret( &sha1, sha1sum );

    memset( padbuf, 0x5C, 48 );

    mbedtls_md5_starts_ret( &md5 );
    mbedtls_md5_update_ret( &md5, session->master, 48 );
    mbedtls_md5_update_ret( &md5, padbuf, 48 );
    mbedtls_md5_update_ret( &md5, md5sum, 16 );
    mbedtls_md5_finish_ret( &md5, buf );

    mbedtls_sha1_starts_ret( &sha1 );
    mbedtls_sha1_update_ret( &sha1, session->master, 48 );
    mbedtls_sha1_update_ret( &sha1, padbuf , 40 );
    mbedtls_sha1_update_ret( &sha1, sha1sum, 20 );
    mbedtls_sha1_finish_ret( &sha1, buf + 16 );

    MBEDTLS_SSL_DEBUG_BUF( 3, "calc finished result", buf, 36 );

    mbedtls_md5_free(  &md5  );
    mbedtls_sha1_free( &sha1 );

    mbedtls_platform_zeroize(  padbuf, sizeof(  padbuf ) );
    mbedtls_platform_zeroize(  md5sum, sizeof(  md5sum ) );
    mbedtls_platform_zeroize( sha1sum, sizeof( sha1sum ) );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
}
#endif /* MBEDTLS_SSL_PROTO_SSL3 */

#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
static void ssl_calc_finished_tls(
                mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{
    int len = 12;
    const char *sender;
    mbedtls_md5_context  md5;
    mbedtls_sha1_context sha1;
    unsigned char padbuf[36];

    mbedtls_ssl_session *session = ssl->session_negotiate;
    if( !session )
        session = ssl->session;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc  finished tls" ) );

    mbedtls_md5_init( &md5 );
    mbedtls_sha1_init( &sha1 );

    mbedtls_md5_clone( &md5, &ssl->handshake->fin_md5 );
    mbedtls_sha1_clone( &sha1, &ssl->handshake->fin_sha1 );

    /*
     * TLSv1:
     *   hash = PRF( master, finished_label,
     *               MD5( handshake ) + SHA1( handshake ) )[0..11]
     */

#if !defined(MBEDTLS_MD5_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished  md5 state", (unsigned char *)
                    md5.state, sizeof(  md5.state ) );
#endif

#if !defined(MBEDTLS_SHA1_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha1 state", (unsigned char *)
                   sha1.state, sizeof( sha1.state ) );
#endif

    sender = ( from == MBEDTLS_SSL_IS_CLIENT )
             ? "client finished"
             : "server finished";

    mbedtls_md5_finish_ret(  &md5, padbuf );
    mbedtls_sha1_finish_ret( &sha1, padbuf + 16 );

    ssl->handshake->tls_prf( session->master, 48, sender,
                             padbuf, 36, buf, len );

    MBEDTLS_SSL_DEBUG_BUF( 3, "calc finished result", buf, len );

    mbedtls_md5_free(  &md5  );
    mbedtls_sha1_free( &sha1 );

    mbedtls_platform_zeroize(  padbuf, sizeof(  padbuf ) );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 */

#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
static void ssl_calc_finished_tls_sha256(
                mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{
    int len = 12;
    const char *sender;
    unsigned char padbuf[32];
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    size_t hash_size;
    psa_hash_operation_t sha256_psa = PSA_HASH_OPERATION_INIT;
    psa_status_t status;
#else
    mbedtls_sha256_context sha256;
#endif

    mbedtls_ssl_session *session = ssl->session_negotiate;
    if( !session )
        session = ssl->session;

    sender = ( from == MBEDTLS_SSL_IS_CLIENT )
             ? "client finished"
             : "server finished";

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    sha256_psa = psa_hash_operation_init();

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc PSA finished tls sha256" ) );

    status = psa_hash_clone( &ssl->handshake->fin_sha256_psa, &sha256_psa );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash clone failed" ) );
        return;
    }

    status = psa_hash_finish( &sha256_psa, padbuf, sizeof( padbuf ), &hash_size );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash finish failed" ) );
        return;
    }
    MBEDTLS_SSL_DEBUG_BUF( 3, "PSA calculated padbuf", padbuf, 32 );
#else

    mbedtls_sha256_init( &sha256 );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc  finished tls sha256" ) );

    mbedtls_sha256_clone( &sha256, &ssl->handshake->fin_sha256 );

    /*
     * TLSv1.2:
     *   hash = PRF( master, finished_label,
     *               Hash( handshake ) )[0.11]
     */

#if !defined(MBEDTLS_SHA256_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha2 state", (unsigned char *)
                   sha256.state, sizeof( sha256.state ) );
#endif

    mbedtls_sha256_finish_ret( &sha256, padbuf );
    mbedtls_sha256_free( &sha256 );
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    ssl->handshake->tls_prf( session->master, 48, sender,
                             padbuf, 32, buf, len );

    MBEDTLS_SSL_DEBUG_BUF( 3, "calc finished result", buf, len );

    mbedtls_platform_zeroize(  padbuf, sizeof(  padbuf ) );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
}
#endif /* MBEDTLS_SHA256_C */

#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)

static void ssl_calc_finished_tls_sha384(
                mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{
    int len = 12;
    const char *sender;
    unsigned char padbuf[48];
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    size_t hash_size;
    psa_hash_operation_t sha384_psa = PSA_HASH_OPERATION_INIT;
    psa_status_t status;
#else
    mbedtls_sha512_context sha512;
#endif

    mbedtls_ssl_session *session = ssl->session_negotiate;
    if( !session )
        session = ssl->session;

    sender = ( from == MBEDTLS_SSL_IS_CLIENT )
                ? "client finished"
                : "server finished";

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    sha384_psa = psa_hash_operation_init();

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc PSA finished tls sha384" ) );

    status = psa_hash_clone( &ssl->handshake->fin_sha384_psa, &sha384_psa );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash clone failed" ) );
        return;
    }

    status = psa_hash_finish( &sha384_psa, padbuf, sizeof( padbuf ), &hash_size );
    if( status != PSA_SUCCESS )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "PSA hash finish failed" ) );
        return;
    }
    MBEDTLS_SSL_DEBUG_BUF( 3, "PSA calculated padbuf", padbuf, 48 );
#else
    mbedtls_sha512_init( &sha512 );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc  finished tls sha384" ) );

    mbedtls_sha512_clone( &sha512, &ssl->handshake->fin_sha512 );

    /*
     * TLSv1.2:
     *   hash = PRF( master, finished_label,
     *               Hash( handshake ) )[0.11]
     */

#if !defined(MBEDTLS_SHA512_ALT)
    MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *)
                   sha512.state, sizeof( sha512.state ) );
#endif
    /* mbedtls_sha512_finish_ret's output parameter is declared as a
     * 64-byte buffer, but sice we're using SHA-384, we know that the
     * output fits in 48 bytes. This is correct C, but GCC 11.1 warns
     * about it.
     */
#if defined(__GNUC__) && __GNUC__ >= 11
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-overflow"
#endif
    mbedtls_sha512_finish_ret( &sha512, padbuf );
#if defined(__GNUC__) && __GNUC__ >= 11
#pragma GCC diagnostic pop
#endif

    mbedtls_sha512_free( &sha512 );
#endif

    ssl->handshake->tls_prf( session->master, 48, sender,
                             padbuf, 48, buf, len );

    MBEDTLS_SSL_DEBUG_BUF( 3, "calc finished result", buf, len );

    mbedtls_platform_zeroize(  padbuf, sizeof( padbuf ) );

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc  finished" ) );
}
#endif /* MBEDTLS_SHA512_C && !MBEDTLS_SHA512_NO_SHA384 */
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

void mbedtls_ssl_handshake_wrapup_free_hs_transform( mbedtls_ssl_context *ssl )
{
    MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup: final free" ) );

    /*
     * Free our handshake params
     */
    mbedtls_ssl_handshake_free( ssl );
    mbedtls_free( ssl->handshake );
    ssl->handshake = NULL;

    /*
     * Free the previous transform and swith in the current one
     */
    if( ssl->transform )
    {
        mbedtls_ssl_transform_free( ssl->transform );
        mbedtls_free( ssl->transform );
    }
    ssl->transform = ssl->transform_negotiate;
    ssl->transform_negotiate = NULL;

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup: final free" ) );
}

void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
{
    int resume = ssl->handshake->resume;

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );

#if defined(MBEDTLS_SSL_RENEGOTIATION)
    if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
    {
        ssl->renego_status =  MBEDTLS_SSL_RENEGOTIATION_DONE;
        ssl->renego_records_seen = 0;
    }
#endif

    /*
     * Free the previous session and switch in the current one
     */
    if( ssl->session )
    {
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
        /* RFC 7366 3.1: keep the EtM state */
        ssl->session_negotiate->encrypt_then_mac =
                  ssl->session->encrypt_then_mac;
#endif

        mbedtls_ssl_session_free( ssl->session );
        mbedtls_free( ssl->session );
    }
    ssl->session = ssl->session_negotiate;
    ssl->session_negotiate = NULL;

    /*
     * Add cache entry
     */
    if( ssl->conf->f_set_cache != NULL &&
        ssl->session->id_len != 0 &&
        resume == 0 )
    {
        if( ssl->conf->f_set_cache( ssl->conf->p_cache, ssl->session ) != 0 )
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "cache did not store session" ) );
    }

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
        ssl->handshake->flight != NULL )
    {
        /* Cancel handshake timer */
        mbedtls_ssl_set_timer( ssl, 0 );

        /* Keep last flight around in case we need to resend it:
         * we need the handshake and transform structures for that */
        MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip freeing handshake and transform" ) );
    }
    else
#endif
        mbedtls_ssl_handshake_wrapup_free_hs_transform( ssl );

    ssl->state++;

    MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
}

int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
{
    int ret, hash_len;

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write finished" ) );

    mbedtls_ssl_update_out_pointers( ssl, ssl->transform_negotiate );

    ssl->handshake->calc_finished( ssl, ssl->out_msg + 4, ssl->conf->endpoint );

    /*
     * RFC 5246 7.4.9 (Page 63) says 12 is the default length and ciphersuites
     * may define some other value. Currently (early 2016), no defined
     * ciphersuite does this (and this is unlikely to change as activity has
     * moved to TLS 1.3 now) so we can keep the hardcoded 12 here.
     */
    hash_len = ( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) ? 36 : 12;

#if defined(MBEDTLS_SSL_RENEGOTIATION)
    ssl->verify_data_len = hash_len;
    memcpy( ssl->own_verify_data, ssl->out_msg + 4, hash_len );
#endif

    ssl->out_msglen  = 4 + hash_len;
    ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
    ssl->out_msg[0]  = MBEDTLS_SSL_HS_FINISHED;

    /*
     * In case of session resuming, invert the client and server
     * ChangeCipherSpec messages order.
     */
    if( ssl->handshake->resume != 0 )
    {
#if defined(MBEDTLS_SSL_CLI_C)
        if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
            ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
#endif
#if defined(MBEDTLS_SSL_SRV_C)
        if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
            ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
#endif
    }
    else
        ssl->state++;

    /*
     * Switch to our negotiated transform and session parameters for outbound
     * data.
     */
    MBEDTLS_SSL_DEBUG_MSG( 3, ( "switching to new transform spec for outbound data" ) );

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
    {
        unsigned char i;

        /* Remember current epoch settings for resending */
        ssl->handshake->alt_transform_out = ssl->transform_out;
        memcpy( ssl->handshake->alt_out_ctr, ssl->cur_out_ctr, 8 );

        /* Set sequence_number to zero */
        memset( ssl->cur_out_ctr + 2, 0, 6 );

        /* Increment epoch */
        for( i = 2; i > 0; i-- )
            if( ++ssl->cur_out_ctr[i - 1] != 0 )
                break;

        /* The loop goes to its end iff the counter is wrapping */
        if( i == 0 )
        {
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS epoch would wrap" ) );
            return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
        }
    }
    else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
    memset( ssl->cur_out_ctr, 0, 8 );

    ssl->transform_out = ssl->transform_negotiate;
    ssl->session_out = ssl->session_negotiate;

#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
    if( mbedtls_ssl_hw_record_activate != NULL )
    {
        if( ( ret = mbedtls_ssl_hw_record_activate( ssl, MBEDTLS_SSL_CHANNEL_OUTBOUND ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_activate", ret );
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
        }
    }
#endif

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
        mbedtls_ssl_send_flight_completed( ssl );
#endif

    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
        return( ret );
    }

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
        ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
        return( ret );
    }
#endif

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write finished" ) );

    return( 0 );
}

#if defined(MBEDTLS_SSL_PROTO_SSL3)
#define SSL_MAX_HASH_LEN 36
#else
#define SSL_MAX_HASH_LEN 12
#endif

int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned int hash_len;
    unsigned char buf[SSL_MAX_HASH_LEN];

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse finished" ) );

    /* There is currently no ciphersuite using another length with TLS 1.2 */
#if defined(MBEDTLS_SSL_PROTO_SSL3)
    if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
        hash_len = 36;
    else
#endif
        hash_len = 12;

    ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 );

    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
        goto exit;
    }

    if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE );
        ret = MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
        goto exit;
    }

    if( ssl->in_msg[0] != MBEDTLS_SSL_HS_FINISHED ||
        ssl->in_hslen  != mbedtls_ssl_hs_hdr_len( ssl ) + hash_len )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
        ret = MBEDTLS_ERR_SSL_BAD_HS_FINISHED;
        goto exit;
    }

    if( mbedtls_ct_memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ),
                      buf, hash_len ) != 0 )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
                                        MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR );
        ret = MBEDTLS_ERR_SSL_BAD_HS_FINISHED;
        goto exit;
    }

#if defined(MBEDTLS_SSL_RENEGOTIATION)
    ssl->verify_data_len = hash_len;
    memcpy( ssl->peer_verify_data, buf, hash_len );
#endif

    if( ssl->handshake->resume != 0 )
    {
#if defined(MBEDTLS_SSL_CLI_C)
        if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
            ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
#endif
#if defined(MBEDTLS_SSL_SRV_C)
        if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
            ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
#endif
    }
    else
        ssl->state++;

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
        mbedtls_ssl_recv_flight_completed( ssl );
#endif

    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse finished" ) );

exit:
    mbedtls_platform_zeroize( buf, hash_len );
    return( ret );
}

static void ssl_handshake_params_init( mbedtls_ssl_handshake_params *handshake )
{
    memset( handshake, 0, sizeof( mbedtls_ssl_handshake_params ) );

#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
    defined(MBEDTLS_SSL_PROTO_TLS1_1)
     mbedtls_md5_init(   &handshake->fin_md5  );
    mbedtls_sha1_init(   &handshake->fin_sha1 );
     mbedtls_md5_starts_ret( &handshake->fin_md5  );
    mbedtls_sha1_starts_ret( &handshake->fin_sha1 );
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_SHA256_C)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    handshake->fin_sha256_psa = psa_hash_operation_init();
    psa_hash_setup( &handshake->fin_sha256_psa, PSA_ALG_SHA_256 );
#else
    mbedtls_sha256_init(   &handshake->fin_sha256    );
    mbedtls_sha256_starts_ret( &handshake->fin_sha256, 0 );
#endif
#endif
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_SHA512_NO_SHA384)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    handshake->fin_sha384_psa = psa_hash_operation_init();
    psa_hash_setup( &handshake->fin_sha384_psa, PSA_ALG_SHA_384 );
#else
    mbedtls_sha512_init(   &handshake->fin_sha512    );
    mbedtls_sha512_starts_ret( &handshake->fin_sha512, 1 );
#endif
#endif
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */

    handshake->update_checksum = ssl_update_checksum_start;

#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
    mbedtls_ssl_sig_hash_set_init( &handshake->hash_algs );
#endif

#if defined(MBEDTLS_DHM_C)
    mbedtls_dhm_init( &handshake->dhm_ctx );
#endif
#if defined(MBEDTLS_ECDH_C)
    mbedtls_ecdh_init( &handshake->ecdh_ctx );
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
    mbedtls_ecjpake_init( &handshake->ecjpake_ctx );
#if defined(MBEDTLS_SSL_CLI_C)
    handshake->ecjpake_cache = NULL;
    handshake->ecjpake_cache_len = 0;
#endif
#endif

#if defined(MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED)
    mbedtls_x509_crt_restart_init( &handshake->ecrs_ctx );
#endif

#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
    handshake->sni_authmode = MBEDTLS_SSL_VERIFY_UNSET;
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
    mbedtls_pk_init( &handshake->peer_pubkey );
#endif
}

void mbedtls_ssl_transform_init( mbedtls_ssl_transform *transform )
{
    memset( transform, 0, sizeof(mbedtls_ssl_transform) );

    mbedtls_cipher_init( &transform->cipher_ctx_enc );
    mbedtls_cipher_init( &transform->cipher_ctx_dec );

#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC)
    mbedtls_md_init( &transform->md_ctx_enc );
    mbedtls_md_init( &transform->md_ctx_dec );
#endif
}

void mbedtls_ssl_session_init( mbedtls_ssl_session *session )
{
    memset( session, 0, sizeof(mbedtls_ssl_session) );
}

static int ssl_handshake_init( mbedtls_ssl_context *ssl )
{
    /* Clear old handshake information if present */
    if( ssl->transform_negotiate )
        mbedtls_ssl_transform_free( ssl->transform_negotiate );
    if( ssl->session_negotiate )
        mbedtls_ssl_session_free( ssl->session_negotiate );
    if( ssl->handshake )
        mbedtls_ssl_handshake_free( ssl );

    /*
     * Either the pointers are now NULL or cleared properly and can be freed.
     * Now allocate missing structures.
     */
    if( ssl->transform_negotiate == NULL )
    {
        ssl->transform_negotiate = mbedtls_calloc( 1, sizeof(mbedtls_ssl_transform) );
    }

    if( ssl->session_negotiate == NULL )
    {
        ssl->session_negotiate = mbedtls_calloc( 1, sizeof(mbedtls_ssl_session) );
    }

    if( ssl->handshake == NULL )
    {
        ssl->handshake = mbedtls_calloc( 1, sizeof(mbedtls_ssl_handshake_params) );
    }
#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
    /* If the buffers are too small - reallocate */

    handle_buffer_resizing( ssl, 0, MBEDTLS_SSL_IN_BUFFER_LEN,
                                    MBEDTLS_SSL_OUT_BUFFER_LEN );
#endif

    /* All pointers should exist and can be directly freed without issue */
    if( ssl->handshake == NULL ||
        ssl->transform_negotiate == NULL ||
        ssl->session_negotiate == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc() of ssl sub-contexts failed" ) );

        mbedtls_free( ssl->handshake );
        mbedtls_free( ssl->transform_negotiate );
        mbedtls_free( ssl->session_negotiate );

        ssl->handshake = NULL;
        ssl->transform_negotiate = NULL;
        ssl->session_negotiate = NULL;

        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
    }

    /* Initialize structures */
    mbedtls_ssl_session_init( ssl->session_negotiate );
    mbedtls_ssl_transform_init( ssl->transform_negotiate );
    ssl_handshake_params_init( ssl->handshake );

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
    {
        ssl->handshake->alt_transform_out = ssl->transform_out;

        if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
            ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_PREPARING;
        else
            ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING;

        mbedtls_ssl_set_timer( ssl, 0 );
    }
#endif

    return( 0 );
}

#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
/* Dummy cookie callbacks for defaults */
static int ssl_cookie_write_dummy( void *ctx,
                      unsigned char **p, unsigned char *end,
                      const unsigned char *cli_id, size_t cli_id_len )
{
    ((void) ctx);
    ((void) p);
    ((void) end);
    ((void) cli_id);
    ((void) cli_id_len);

    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}

static int ssl_cookie_check_dummy( void *ctx,
                      const unsigned char *cookie, size_t cookie_len,
                      const unsigned char *cli_id, size_t cli_id_len )
{
    ((void) ctx);
    ((void) cookie);
    ((void) cookie_len);
    ((void) cli_id);
    ((void) cli_id_len);

    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */

/*
 * Initialize an SSL context
 */
void mbedtls_ssl_init( mbedtls_ssl_context *ssl )
{
    memset( ssl, 0, sizeof( mbedtls_ssl_context ) );
}

/*
 * Setup an SSL context
 */

int mbedtls_ssl_setup( mbedtls_ssl_context *ssl,
                       const mbedtls_ssl_config *conf )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN;
    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN;

    ssl->conf = conf;

    /*
     * Prepare base structures
     */

    /* Set to NULL in case of an error condition */
    ssl->out_buf = NULL;

#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
    ssl->in_buf_len = in_buf_len;
#endif
    ssl->in_buf = mbedtls_calloc( 1, in_buf_len );
    if( ssl->in_buf == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%" MBEDTLS_PRINTF_SIZET " bytes) failed", in_buf_len ) );
        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
        goto error;
    }

#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
    ssl->out_buf_len = out_buf_len;
#endif
    ssl->out_buf = mbedtls_calloc( 1, out_buf_len );
    if( ssl->out_buf == NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%" MBEDTLS_PRINTF_SIZET " bytes) failed", out_buf_len ) );
        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
        goto error;
    }

    mbedtls_ssl_reset_in_out_pointers( ssl );

#if defined(MBEDTLS_SSL_DTLS_SRTP)
    memset( &ssl->dtls_srtp_info, 0, sizeof(ssl->dtls_srtp_info) );
#endif

    if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
        goto error;

    return( 0 );

error:
    mbedtls_free( ssl->in_buf );
    mbedtls_free( ssl->out_buf );

    ssl->conf = NULL;

#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
    ssl->in_buf_len = 0;
    ssl->out_buf_len = 0;
#endif
    ssl->in_buf = NULL;
    ssl->out_buf = NULL;

    ssl->in_hdr = NULL;
    ssl->in_ctr = NULL;
    ssl->in_len = NULL;
    ssl->in_iv = NULL;
    ssl->in_msg = NULL;

    ssl->out_hdr = NULL;
    ssl->out_ctr = NULL;
    ssl->out_len = NULL;
    ssl->out_iv = NULL;
    ssl->out_msg = NULL;

    return( ret );
}

/*
 * Reset an initialized and used SSL context for re-use while retaining
 * all application-set variables, function pointers and data.
 *
 * If partial is non-zero, keep data in the input buffer and client ID.
 * (Use when a DTLS client reconnects from the same port.)
 */
int mbedtls_ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
    size_t in_buf_len = ssl->in_buf_len;
    size_t out_buf_len = ssl->out_buf_len;
#else
    size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN;
    size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN;
#endif

#if !defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) ||     \
    !defined(MBEDTLS_SSL_SRV_C)
    ((void) partial);
#endif

    ssl->state = MBEDTLS_SSL_HELLO_REQUEST;

    /* Cancel any possibly running timer */
    mbedtls_ssl_set_timer( ssl, 0 );

#if defined(MBEDTLS_SSL_RENEGOTIATION)
    ssl->renego_status = MBEDTLS_SSL_INITIAL_HANDSHAKE;
    ssl->renego_records_seen = 0;

    ssl->verify_data_len = 0;
    memset( ssl->own_verify_data, 0, MBEDTLS_SSL_VERIFY_DATA_MAX_LEN );
    memset( ssl->peer_verify_data, 0, MBEDTLS_SSL_VERIFY_DATA_MAX_LEN );
#endif
    ssl->secure_renegotiation = MBEDTLS_SSL_LEGACY_RENEGOTIATION;

    ssl->in_offt = NULL;
    mbedtls_ssl_reset_in_out_pointers( ssl );

    ssl->in_msgtype = 0;
    ssl->in_msglen = 0;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
    ssl->next_record_offset = 0;
    ssl->in_epoch = 0;
#endif
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
    mbedtls_ssl_dtls_replay_reset( ssl );
#endif

    ssl->in_hslen = 0;
    ssl->nb_zero = 0;

    ssl->keep_current_message = 0;

    ssl->out_msgtype = 0;
    ssl->out_msglen = 0;
    ssl->out_left = 0;
#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
    if( ssl->split_done != MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED )
        ssl->split_done = 0;
#endif

    memset( ssl->cur_out_ctr, 0, sizeof( ssl->cur_out_ctr ) );

    ssl->transform_in = NULL;
    ssl->transform_out = NULL;

    ssl->session_in = NULL;
    ssl->session_out = NULL;

    memset( ssl->out_buf, 0, out_buf_len );

#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C)
    if( partial == 0 )
#endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */
    {
        ssl->in_left = 0;
        memset( ssl->in_buf, 0, in_buf_len );
    }

#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
    if( mbedtls_ssl_hw_record_reset != NULL )
    {
        MBEDTLS_SSL_DEBUG_MSG( 2, ( "going for mbedtls_ssl_hw_record_reset()" ) );
        if( ( ret = mbedtls_ssl_hw_record_reset( ssl ) ) != 0 )
        {
            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_reset", ret );
            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
        }
    }
#endif

    if( ssl->transform )
    {
        mbedtls_ssl_transform_free( ssl->transform );
        mbedtls_free( ssl->transform );
        ssl->transform = NULL;
    }

    if( ssl->session )
    {
        mbedtls_ssl_session_free( ssl->session );
        mbedtls_free( ssl->session );
        ssl->session = NULL;
    }

#if defined(MBEDTLS_SSL_ALPN)
    ssl->alpn_chosen = NULL;
#endif

#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE)
    if( partial == 0 )
#endif
    {
        mbedtls_free( ssl->cli_id );
        ssl->cli_id = NULL;
        ssl->cli_id_len = 0;
    }
#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 mbedtls_ssl_session_reset( mbedtls_ssl_context *ssl )
{
    return( mbedtls_ssl_session_reset_int( ssl, 0 ) );
}

/*
 * SSL set accessors
 */
void mbedtls_ssl_conf_endpoint( mbedtls_ssl_config *conf, int endpoint )
{
    conf->endpoint   = endpoint;
}

void mbedtls_ssl_conf_transport( mbedtls_ssl_config *conf, int transport )
{
    conf->transport = transport;
}

#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
void mbedtls_ssl_conf_dtls_anti_replay( mbedtls_ssl_config *conf, char mode )
{
    conf->anti_replay = mode;
}
#endif

#if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT)
void mbedtls_ssl_conf_dtls_badmac_limit( mbedtls_ssl_config *conf, unsigned limit )
{
    conf->badmac_limit = limit;
}
#endif

#if defined(MBEDTLS_SSL_PROTO_DTLS)

void mbedtls_ssl_set_datagram_packing( mbedtls_ssl_context *ssl,
                                       unsigned allow_packing )
{
    ssl->disable_datagram_packing = !allow_packing;
}

void mbedtls_ssl_conf_handshake_timeout( mbedtls_ssl_config *conf,
                                         uint32_t min, uint32_t max )
{
    conf->hs_timeout_min = min;
    conf->hs_timeout_max = max;
}
#endif

void mbedtls_ssl_conf_authmode( mbedtls_ssl_config *conf, int authmode )
{
    conf->authmode   = authmode;
}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
void mbedtls_ssl_conf_verify( mbedtls_ssl_config *conf,
                     int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                     void *p_vrfy )
{
    conf->f_vrfy      = f_vrfy;
    conf->p_vrfy      = p_vrfy;
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

void mbedtls_ssl_conf_rng( mbedtls_ssl_config *conf,
                  int (*f_rng)(void *, unsigned char *, size_t),
                  void *p_rng )
{
    conf->f_rng      = f_rng;
    conf->p_rng      = p_rng;
}

void mbedtls_ssl_conf_dbg( mbedtls_ssl_config *conf,
                  void (*f_dbg)(void *, int, const char *, int, const char *),
                  void  *p_dbg )
{
    conf->f_dbg      = f_dbg;
    conf->p_dbg      = p_dbg;
}

void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl,
        void *p_bio,
        mbedtls_ssl_send_t *f_send,
        mbedtls_ssl_recv_t *f_recv,
        mbedtls_ssl_recv_timeout_t *f_recv_timeout )
{
    ssl->p_bio          = p_bio;
    ssl->f_send         = f_send;
    ssl->f_recv         = f_recv;
    ssl->f_recv_timeout = f_recv_timeout;
}

#if defined(MBEDTLS_SSL_PROTO_DTLS)
void mbedtls_ssl_set_mtu( mbedtls_ssl_context *ssl, uint16_t mtu )
{
    ssl->mtu = mtu;
}
#endif

void mbedtls_ssl_conf_read_timeout( mbedtls_ssl_config *conf, uint32_t timeout )
{
    conf->read_timeout   = timeout;
}

void mbedtls_ssl_set_timer_cb( mbedtls_ssl_context *ssl,
                               void *p_timer,
                               mbedtls_ssl_set_timer_t *f_set_timer,
                               mbedtls_ssl_get_timer_t *f_get_timer )
{
    ssl->p_timer        = p_timer;
    ssl->f_set_timer    = f_set_timer;
    ssl->f_get_timer    = f_get_timer;

    /* Make sure we start with no timer running */
    mbedtls_ssl_set_timer( ssl, 0 );
}

#if defined(MBEDTLS_SSL_SRV_C)
void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
        void *p_cache,
        int (*f_get_cache)(void *, mbedtls_ssl_session *),
        int (*f_set_cache)(void *, const mbedtls_ssl_session *) )
{
    conf->p_cache = p_cache;
    conf->f_get_cache = f_get_cache;
    conf->f_set_cache = f_set_cache;
}
#endif /* MBEDTLS_SSL_SRV_C */

#if defined(MBEDTLS_SSL_CLI_C)
int mbedtls_ssl_set_session( mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    if( ssl == NULL ||
        session == NULL ||
        ssl->session_negotiate == NULL ||
        ssl->conf->endpoint != MBEDTLS_SSL_IS_CLIENT )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    if( ( ret = mbedtls_ssl_session_copy( ssl->session_negotiate,
                                          session ) ) != 0 )
        return( ret );

    ssl->handshake->resume = 1;

    return( 0 );
}
#endif /* MBEDTLS_SSL_CLI_C */

void mbedtls_ssl_conf_ciphersuites( mbedtls_ssl_config *conf,
                                   const int *ciphersuites )
{
    conf->ciphersuite_list[MBEDTLS_SSL_MINOR_VERSION_0] = ciphersuites;
    conf->ciphersuite_list[MBEDTLS_SSL_MINOR_VERSION_1] = ciphersuites;
    conf->ciphersuite_list[MBEDTLS_SSL_MINOR_VERSION_2] = ciphersuites;
    conf->ciphersuite_list[MBEDTLS_SSL_MINOR_VERSION_3] = ciphersuites;
}

void mbedtls_ssl_conf_ciphersuites_for_version( mbedtls_ssl_config *conf,
                                       const int *ciphersuites,
                                       int major, int minor )
{
    if( major != MBEDTLS_SSL_MAJOR_VERSION_3 )
        return;

    if( minor < MBEDTLS_SSL_MINOR_VERSION_0 || minor > MBEDTLS_SSL_MINOR_VERSION_3 )
        return;

    conf->ciphersuite_list[minor] = ciphersuites;
}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
void mbedtls_ssl_conf_cert_profile( mbedtls_ssl_config *conf,
                                    const mbedtls_x509_crt_profile *profile )
{
    conf->cert_profile = profile;
}

/* Append a new keycert entry to a (possibly empty) list */
static int ssl_append_key_cert( mbedtls_ssl_key_cert **head,
                                mbedtls_x509_crt *cert,
                                mbedtls_pk_context *key )
{
    mbedtls_ssl_key_cert *new_cert;

    new_cert = mbedtls_calloc( 1, sizeof( mbedtls_ssl_key_cert ) );
    if( new_cert == NULL )
        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

    new_cert->cert = cert;
    new_cert->key  = key;
    new_cert->next = NULL;

    /* Update head is the list was null, else add to the end */
    if( *head == NULL )
    {
        *head = new_cert;
    }
    else
    {
        mbedtls_ssl_key_cert *cur = *head;
        while( cur->next != NULL )
            cur = cur->next;
        cur->next = new_cert;
    }

    return( 0 );
}

int mbedtls_ssl_conf_own_cert( mbedtls_ssl_config *conf,
                              mbedtls_x509_crt *own_cert,
                              mbedtls_pk_context *pk_key )
{
    return( ssl_append_key_cert( &conf->key_cert, own_cert, pk_key ) );
}

void mbedtls_ssl_conf_ca_chain( mbedtls_ssl_config *conf,
                               mbedtls_x509_crt *ca_chain,
                               mbedtls_x509_crl *ca_crl )
{
    conf->ca_chain   = ca_chain;
    conf->ca_crl     = ca_crl;

#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
    /* mbedtls_ssl_conf_ca_chain() and mbedtls_ssl_conf_ca_cb()
     * cannot be used together. */
    conf->f_ca_cb = NULL;
    conf->p_ca_cb = NULL;
#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
}

#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
void mbedtls_ssl_conf_ca_cb( mbedtls_ssl_config *conf,
                             mbedtls_x509_crt_ca_cb_t f_ca_cb,
                             void *p_ca_cb )
{
    conf->f_ca_cb = f_ca_cb;
    conf->p_ca_cb = p_ca_cb;

    /* mbedtls_ssl_conf_ca_chain() and mbedtls_ssl_conf_ca_cb()
     * cannot be used together. */
    conf->ca_chain   = NULL;
    conf->ca_crl     = NULL;
}
#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
int mbedtls_ssl_set_hs_own_cert( mbedtls_ssl_context *ssl,
                                 mbedtls_x509_crt *own_cert,
                                 mbedtls_pk_context *pk_key )
{
    return( ssl_append_key_cert( &ssl->handshake->sni_key_cert,
                                 own_cert, pk_key ) );
}

void mbedtls_ssl_set_hs_ca_chain( mbedtls_ssl_context *ssl,
                                  mbedtls_x509_crt *ca_chain,
                                  mbedtls_x509_crl *ca_crl )
{
    ssl->handshake->sni_ca_chain   = ca_chain;
    ssl->handshake->sni_ca_crl     = ca_crl;
}

void mbedtls_ssl_set_hs_authmode( mbedtls_ssl_context *ssl,
                                  int authmode )
{
    ssl->handshake->sni_authmode = authmode;
}
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */

#if defined(MBEDTLS_X509_CRT_PARSE_C)
void mbedtls_ssl_set_verify( mbedtls_ssl_context *ssl,
                     int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                     void *p_vrfy )
{
    ssl->f_vrfy = f_vrfy;
    ssl->p_vrfy = p_vrfy;
}
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
/*
 * Set EC J-PAKE password for current handshake
 */
int mbedtls_ssl_set_hs_ecjpake_password( mbedtls_ssl_context *ssl,
                                         const unsigned char *pw,
                                         size_t pw_len )
{
    mbedtls_ecjpake_role role;

    if( ssl->handshake == NULL || ssl->conf == NULL )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
        role = MBEDTLS_ECJPAKE_SERVER;
    else
        role = MBEDTLS_ECJPAKE_CLIENT;

    return( mbedtls_ecjpake_setup( &ssl->handshake->ecjpake_ctx,
                                   role,
                                   MBEDTLS_MD_SHA256,
                                   MBEDTLS_ECP_DP_SECP256R1,
                                   pw, pw_len ) );
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)

static void ssl_conf_remove_psk( mbedtls_ssl_config *conf )
{
    /* Remove reference to existing PSK, if any. */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    if( ! mbedtls_svc_key_id_is_null( conf->psk_opaque ) )
    {
        /* The maintenance of the PSK key slot is the
         * user's responsibility. */
        conf->psk_opaque = MBEDTLS_SVC_KEY_ID_INIT;
    }
    /* This and the following branch should never
     * be taken simultaenously as we maintain the
     * invariant that raw and opaque PSKs are never
     * configured simultaneously. As a safeguard,
     * though, `else` is omitted here. */
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    if( conf->psk != NULL )
    {
        mbedtls_platform_zeroize( conf->psk, conf->psk_len );

        mbedtls_free( conf->psk );
        conf->psk = NULL;
        conf->psk_len = 0;
    }

    /* Remove reference to PSK identity, if any. */
    if( conf->psk_identity != NULL )
    {
        mbedtls_free( conf->psk_identity );
        conf->psk_identity = NULL;
        conf->psk_identity_len = 0;
    }
}

/* This function assumes that PSK identity in the SSL config is unset.
 * It checks that the provided identity is well-formed and attempts
 * to make a copy of it in the SSL config.
 * On failure, the PSK identity in the config remains unset. */
static int ssl_conf_set_psk_identity( mbedtls_ssl_config *conf,
                                      unsigned char const *psk_identity,
                                      size_t psk_identity_len )
{
    /* Identity len will be encoded on two bytes */
    if( psk_identity               == NULL ||
        ( psk_identity_len >> 16 ) != 0    ||
        psk_identity_len > MBEDTLS_SSL_OUT_CONTENT_LEN )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    conf->psk_identity = mbedtls_calloc( 1, psk_identity_len );
    if( conf->psk_identity == NULL )
        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

    conf->psk_identity_len = psk_identity_len;
    memcpy( conf->psk_identity, psk_identity, conf->psk_identity_len );

    return( 0 );
}

int mbedtls_ssl_conf_psk( mbedtls_ssl_config *conf,
                const unsigned char *psk, size_t psk_len,
                const unsigned char *psk_identity, size_t psk_identity_len )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    /* Remove opaque/raw PSK + PSK Identity */
    ssl_conf_remove_psk( conf );

    /* Check and set raw PSK */
    if( psk == NULL )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    if( psk_len == 0 )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    if( psk_len > MBEDTLS_PSK_MAX_LEN )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    if( ( conf->psk = mbedtls_calloc( 1, psk_len ) ) == NULL )
        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
    conf->psk_len = psk_len;
    memcpy( conf->psk, psk, conf->psk_len );

    /* Check and set PSK Identity */
    ret = ssl_conf_set_psk_identity( conf, psk_identity, psk_identity_len );
    if( ret != 0 )
        ssl_conf_remove_psk( conf );

    return( ret );
}

static void ssl_remove_psk( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) )
    {
        ssl->handshake->psk_opaque = MBEDTLS_SVC_KEY_ID_INIT;
    }
    else
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    if( ssl->handshake->psk != NULL )
    {
        mbedtls_platform_zeroize( ssl->handshake->psk,
                                  ssl->handshake->psk_len );
        mbedtls_free( ssl->handshake->psk );
        ssl->handshake->psk_len = 0;
    }
}

int mbedtls_ssl_set_hs_psk( mbedtls_ssl_context *ssl,
                            const unsigned char *psk, size_t psk_len )
{
    if( psk == NULL || ssl->handshake == NULL )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    if( psk_len > MBEDTLS_PSK_MAX_LEN )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    ssl_remove_psk( ssl );

    if( ( ssl->handshake->psk = mbedtls_calloc( 1, psk_len ) ) == NULL )
        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

    ssl->handshake->psk_len = psk_len;
    memcpy( ssl->handshake->psk, psk, ssl->handshake->psk_len );

    return( 0 );
}

#if defined(MBEDTLS_USE_PSA_CRYPTO)
int mbedtls_ssl_conf_psk_opaque( mbedtls_ssl_config *conf,
                                 psa_key_id_t psk,
                                 const unsigned char *psk_identity,
                                 size_t psk_identity_len )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    /* Clear opaque/raw PSK + PSK Identity, if present. */
    ssl_conf_remove_psk( conf );

    /* Check and set opaque PSK */
    if( mbedtls_svc_key_id_is_null( psk ) )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    conf->psk_opaque = psk;

    /* Check and set PSK Identity */
    ret = ssl_conf_set_psk_identity( conf, psk_identity,
                                     psk_identity_len );
    if( ret != 0 )
        ssl_conf_remove_psk( conf );

    return( ret );
}

int mbedtls_ssl_set_hs_psk_opaque( mbedtls_ssl_context *ssl,
                                   psa_key_id_t psk )
{
    if( ( mbedtls_svc_key_id_is_null( psk ) ) ||
        ( ssl->handshake == NULL ) )
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );

    ssl_remove_psk( ssl );
    ssl->handshake->psk_opaque = psk;
    return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */

void mbedtls_ssl_conf_psk_cb( mbedtls_ssl_config *conf,
                     int (*f_psk)(void *, mbedtls_ssl_context *, const unsigned char *,
                     size_t),
                     void *p_psk )
{
    conf->f_psk = f_psk;
    conf->p_psk = p_psk;
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */

#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_SRV_C)

#if !defined(MBEDTLS_DEPRECATED_REMOVED)
int mbedtls_ssl_conf_dh_param( mbedtls_ssl_config *conf, const char *dhm_P, const char *dhm_G )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    if( ( ret = mbedtls_mpi_read_string( &conf->dhm_P, 16, dhm_P ) ) != 0 ||
        ( ret = mbedtls_mpi_read_string( &conf->dhm_G, 16, dhm_G ) ) != 0 )
    {
        mbedtls_mpi_free( &conf->dhm_P );
        mbedtls_mpi_free( &conf->dhm_G );
        return( ret );
    }

    return( 0 );
}
#endif /* MBEDTLS_DEPRECATED_REMOVED */

int mbedtls_ssl_conf_dh_param_bin( mbedtls_ssl_config *conf,
                                   const unsigned char *dhm_P, size_t P_len,
                                   const unsigned char *dhm_G, size_t G_len )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    if( ( ret = mbedtls_mpi_read_binary( &conf->dhm_P, dhm_P, P_len ) ) != 0 ||
        ( ret = mbedtls_mpi_read_binary( &conf->dhm_G, dhm_G, G_len ) ) != 0 )
    {
        mbedtls_mpi_free( &conf->dhm_P );
        mbedtls_mpi_free( &conf->dhm_G );
        return( ret );
    }

    return( 0 );
}

int mbedtls_ssl_conf_dh_param_ctx( mbedtls_ssl_config *conf, mbedtls_dhm_context *dhm_ctx )
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    if( ( ret = mbedtls_mpi_copy( &conf->dhm_P, &dhm_ctx->P ) ) != 0 ||
        ( ret = mbedtls_mpi_copy( &conf->dhm_G, &dhm_ctx->G ) ) != 0 )
    {
        mbedtls_mpi_free( &conf->dhm_P );
        mbedtls_mpi_free( &conf->dhm_G );
        return( ret );
    }

    return( 0 );
}
#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_SRV_C */

#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
/*
 * Set the minimum length for Diffie-Hellman parameters
 */
void mbedtls_ssl_conf_dhm_min_bitlen( mbedtls_ssl_config *conf,
                                      unsigned int bitlen )
{
    conf->dhm_min_bitlen = bitlen;
}
#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */

#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
 * Set allowed/preferred hashes for handshake signatures
 */
void mbedtls_ssl_conf_sig_hashes( mbedtls_ssl_config *conf,
                                  const int *hashes )
{
    conf->sig_hashes = hashes;
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */

#if defined(MBEDTLS_ECP_C)
/*
 * Set the allowed elliptic curves
 */
void mbedtls_ssl_conf_curves( mbedtls_ssl_config *conf,
                             const mbedtls_ecp_group_id *curve_list )
{
    conf->curve_list = curve_list;
}
#endif /* MBEDTLS_ECP_C */

#if defined(MBEDTLS_X509_CRT_PARSE_C)
int mbedtls_ssl_set_hostname( mbedtls_ssl_context *ssl, const char *hostname )
{
    /* Initialize to suppress unnecessary compiler warning */
    size_t hostname_len = 0;

    /* Check if new hostname is valid before
     * making any change to current one */
    if( hostname != NULL )
    {
        hostname_len = strlen( hostname );

        if( hostname_len > MBEDTLS_SSL_MAX_HOST_NAME_LEN )
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    /* Now it's clear that we will overwrite the old hostname,
     * so we can free it safely */

    if( ssl->hostname != NULL )
    {
        mbedtls_platform_zeroize( ssl->hostname, strlen( ssl->hostname ) );
        mbedtls_free( ssl->hostname );
    }

    /* Passing NULL as hostname shall clear the old one */

    if( hostname == NULL )
    {
        ssl->hostname = NULL;
    }
    else
    {
        ssl->hostname = mbedtls_calloc( 1, hostname_len + 1 );
        if( ssl->hostname == NULL )
            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );

        memcpy( ssl->hostname, hostname, hostname_len );

        ssl->hostname[hostname_len] = '\0';
    }

    return( 0 );
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
void mbedtls_ssl_conf_sni( mbedtls_ssl_config *conf,
                  int (*f_sni)(void *, mbedtls_ssl_context *,
                                const unsigned char *, size_t),
                  void *p_sni )
{
    conf->f_sni = f_sni;
    conf->p_sni = p_sni;
}
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */

#if defined(MBEDTLS_SSL_ALPN)
int mbedtls_ssl_conf_alpn_protocols( mbedtls_ssl_config *conf, const char **protos )
{
    size_t cur_len, tot_len;
    const char **p;

    /*
     * RFC 7301 3.1: "Empty strings MUST NOT be included and byte strings
     * MUST NOT be truncated."
     * We 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 > MBEDTLS_SSL_MAX_ALPN_NAME_LEN ) ||
            ( tot_len > MBEDTLS_SSL_MAX_ALPN_LIST_LEN ) )
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    conf->alpn_list = protos;

    return( 0 );
}

const char *mbedtls_ssl_get_alpn_protocol( const mbedtls_ssl_context *ssl )
{
    return( ssl->alpn_chosen );
}
#endif /* MBEDTLS_SSL_ALPN */

#if defined(MBEDTLS_SSL_DTLS_SRTP)
void mbedtls_ssl_conf_srtp_mki_value_supported( mbedtls_ssl_config *conf,
                                                int support_mki_value )
{
    conf->dtls_srtp_mki_support = support_mki_value;
}

int mbedtls_ssl_dtls_srtp_set_mki_value( mbedtls_ssl_context *ssl,
                                         unsigned char *mki_value,
                                         uint16_t mki_len )
{
    if( mki_len > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED )
    {
        return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
    }

    memcpy( ssl->dtls_srtp_info.mki_value, mki_value, mki_len );
    ssl->dtls_srtp_info.mki_len = mki_len;
    return( 0 );
}

int mbedtls_ssl_conf_dtls_srtp_protection_profiles( mbedtls_ssl_config *conf,
                                                    const mbedtls_ssl_srtp_profile *profiles )
{
    const mbedtls_ssl_srtp_profile *p;
    size_t list_size = 0;

    /* check the profiles list: all entry must be valid,
     * its size cannot be more than the total number of supported profiles, currently 4 */
    for( p = profiles; *p != MBEDTLS_TLS_SRTP_UNSET &&
                       list_size <= MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH;
         p++ )
    {
        if( mbedtls_ssl_check_srtp_profile_value( *p ) != MBEDTLS_TLS_SRTP_UNSET )
        {
            list_size++;
        }
        else
        {
            /* unsupported value, stop parsing and set the size to an error value */
            list_size = MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH + 1;
        }
    }

    if( list_size > MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH )
    {
                conf->dtls_srtp_profile_list = NULL;
                conf->dtls_srtp_profile_list_len = 0;
                return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    conf->dtls_srtp_profile_list = profiles;
    conf->dtls_srtp_profile_list_len = list_size;

    return( 0 );
}

void mbedtls_ssl_get_dtls_srtp_negotiation_result( const mbedtls_ssl_context *ssl,
                                                   mbedtls_dtls_srtp_info *dtls_srtp_info )
{
    dtls_srtp_info->chosen_dtls_srtp_profile = ssl->dtls_srtp_info.chosen_dtls_srtp_profile;
    /* do not copy the mki value if there is no chosen profile */
    if( dtls_srtp_info->chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET )
    {
        dtls_srtp_info->mki_len = 0;
    }
    else
    {
        dtls_srtp_info->mki_len = ssl->dtls_srtp_info.mki_len;
        memcpy( dtls_srtp_info->mki_value, ssl->dtls_srtp_info.mki_value,
                ssl->dtls_srtp_info.mki_len );
    }
}
#endif /* MBEDTLS_SSL_DTLS_SRTP */

void mbedtls_ssl_conf_max_version( mbedtls_ssl_config *conf, int major, int minor )
{
    conf->max_major_ver = major;
    conf->max_minor_ver = minor;
}

void mbedtls_ssl_conf_min_version( mbedtls_ssl_config *conf, int major, int minor )
{
    conf->min_major_ver = major;
    conf->min_minor_ver = minor;
}

#if defined(MBEDTLS_SSL_FALLBACK_SCSV) && defined(MBEDTLS_SSL_CLI_C)
void mbedtls_ssl_conf_fallback( mbedtls_ssl_config *conf, char fallback )
{
    conf->fallback = fallback;
}
#endif

#if defined(MBEDTLS_SSL_SRV_C)
void mbedtls_ssl_conf_cert_req_ca_list( mbedtls_ssl_config *conf,
                                          char cert_req_ca_list )
{
    conf->cert_req_ca_list = cert_req_ca_list;
}
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
void mbedtls_ssl_conf_encrypt_then_mac( mbedtls_ssl_config *conf, char etm )
{
    conf->encrypt_then_mac = etm;
}
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
void mbedtls_ssl_conf_extended_master_secret( mbedtls_ssl_config *conf, char ems )
{
    conf->extended_ms = ems;
}
#endif

#if defined(MBEDTLS_ARC4_C)
void mbedtls_ssl_conf_arc4_support( mbedtls_ssl_config *conf, char arc4 )
{
    conf->arc4_disabled = arc4;
}
#endif

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
int mbedtls_ssl_conf_max_frag_len( mbedtls_ssl_config *conf, unsigned char mfl_code )
{
    if( mfl_code >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID ||
        ssl_mfl_code_to_length( mfl_code ) > MBEDTLS_TLS_EXT_ADV_CONTENT_LEN )
    {
        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
    }

    conf->mfl_code = mfl_code;

    return( 0 );
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
void mbedtls_ssl_conf_truncated_hmac( mbedtls_ssl_config *conf, int truncate )
{
    conf->trunc_hmac = truncate;
}
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */

#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
void mbedtls_ssl_conf_cbc_record_splitting( mbedtls_ssl_config *conf, char split )
{
    conf->cbc_record_splitting = split;
}
#endif

void mbedtls_ssl_conf_legacy_renegotiation( mbedtls_ssl_config *conf, int allow_legacy )
{
    conf->allow_legacy_renegotiation = allow_legacy;
}

#if defined(MBEDTLS_SSL_RENEGOTIATION)
void mbedtls_ssl_conf_renegotiation( mbedtls_ssl_config *conf, int renegotiation )
{
    conf->disable_renegotiation = renegotiation;
}

void mbedtls_ssl_conf_renegotiation_enforced( mbedtls_ssl_config *conf, int max_records )
{
    conf->renego_max_records = max_records;
}

void mbedtls_ssl_conf_renegotiation_period( mbedtls_ssl_config *conf,
                                   const unsigned char period[8] )
{
    memcpy( conf->renego_period, period, 8 );
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
#if defined(MBEDTLS_SSL_CLI_C)
void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets )
{
    conf->session_tickets = use_tickets;
}
#endif

#if defined(MBEDTLS_SSL_SRV_C)
void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
        mbedtls_ssl_ticket_write_t *f_ticket_write,
        mbedtls_ssl_ticket_parse_t *f_ticket_parse,
        void *p_ticket )
{
    conf->f_ticket_write = f_ticket_write;
    conf->f_ticket_parse = f_ticket_parse;
    conf->p_ticket       = p_ticket;
}
#endif
#endif /* MBEDTLS_SSL_SESSION_TICKETS */

#if defined(MBEDTLS_SSL_EXPORT_KEYS)
void mbedtls_ssl_conf_export_keys_cb( mbedtls_ssl_config *conf,
        mbedtls_ssl_export_keys_t *f_export_keys,
        void *p_export_keys )
{
    conf->f_export_keys = f_export_keys;
    conf->p_export_keys = p_export_keys;
}

void mbedtls_ssl_conf_export_keys_ext_cb( mbedtls_ssl_config *conf,
        mbedtls_ssl_export_keys_ext_t *f_export_keys_ext,
        void *p_export_keys )
{
    conf->f_export_keys_ext = f_export_keys_ext;
    conf->p_export_keys = p_export_keys;
}
#endif

#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
void mbedtls_ssl_conf_async_private_cb(
    mbedtls_ssl_config *conf,
    mbedtls_ssl_async_sign_t *f_async_sign,
    mbedtls_ssl_async_decrypt_t *f_async_decrypt,
    mbedtls_ssl_async_resume_t *f_async_resume,
    mbedtls_ssl_async_cancel_t *f_async_cancel,
    void *async_config_data )
{
    conf->f_async_sign_start = f_async_sign;
    conf->f_async_decrypt_start = f_async_decrypt;
    conf->f_async_resume = f_async_resume;
    conf->f_async_cancel = f_async_cancel;
    conf->p_async_config_data = async_config_data;
}

void *mbedtls_ssl_conf_get_async_config_data( const mbedtls_ssl_config *conf )
{
    return( conf->p_async_config_data );
}

void *mbedtls_ssl_get_async_operation_data( const mbedtls_ssl_context *ssl )
{
    if( ssl->handshake == NULL )
        return( NULL );
    else
        return( ssl->handshake->user_async_ctx );
}

void mbedtls_ssl_set_async_operation_data( mbedtls_ssl_context *ssl,
                                 void *ctx )
{
    if( ssl->handshake != NULL )
        ssl->handshake->user_async_ctx = ctx;
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */

/*
 * SSL get accessors
 */
uint32_t mbedtls_ssl_get_verify_result( const mbedtls_ssl_context *ssl )
{
    if( ssl->session != NULL )
        return( ssl->session->verify_result );

    if( ssl->session_negotiate != NULL )
        return( ssl->session_negotiate->verify_result );

    return( 0xFFFFFFFF );
}

const char *mbedtls_ssl_get_ciphersuite( const mbedtls_ssl_context *ssl )
{
    if( ssl == NULL || ssl->session == NULL )
        return( NULL );

    return mbedtls_ssl_get_ciphersuite_name( ssl->session->ciphersuite );
}

const char *mbedtls_ssl_get_version( const mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
    {
        switch( ssl->minor_ver )
        {
            case MBEDTLS_SSL_MINOR_VERSION_2:
                return( "DTLSv1.0" );

            case MBEDTLS_SSL_MINOR_VERSION_3:
                return( "DTLSv1.2" );

            default:
                return( "unknown (DTLS)" );
        }
    }
#endif

    switch( ssl->minor_ver )
    {
        case MBEDTLS_SSL_MINOR_VERSION_0:
            return( "SSLv3.0" );

        case MBEDTLS_SSL_MINOR_VERSION_1:
            return( "TLSv1.0" );

        case MBEDTLS_SSL_MINOR_VERSION_2:
            return( "TLSv1.1" );

        case MBEDTLS_SSL_MINOR_VERSION_3:
            return( "TLSv1.2" );

        default:
            return( "unknown" );
    }
}

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
size_t mbedtls_ssl_get_input_max_frag_len( const mbedtls_ssl_context *ssl )
{
    size_t max_len = MBEDTLS_SSL_MAX_CONTENT_LEN;
    size_t read_mfl;

    /* Use the configured MFL for the client if we're past SERVER_HELLO_DONE */
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
        ssl->state >= MBEDTLS_SSL_SERVER_HELLO_DONE )
    {
        return ssl_mfl_code_to_length( ssl->conf->mfl_code );
    }

    /* Check if a smaller max length was negotiated */
    if( ssl->session_out != NULL )
    {
        read_mfl = ssl_mfl_code_to_length( ssl->session_out->mfl_code );
        if( read_mfl < max_len )
        {
            max_len = read_mfl;
        }
    }

    // During a handshake, use the value being negotiated
    if( ssl->session_negotiate != NULL )
    {
        read_mfl = ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code );
        if( read_mfl < max_len )
        {
            max_len = read_mfl;
        }
    }

    return( max_len );
}

size_t mbedtls_ssl_get_output_max_frag_len( const mbedtls_ssl_context *ssl )
{
    size_t max_len;

    /*
     * Assume mfl_code is correct since it was checked when set
     */
    max_len = ssl_mfl_code_to_length( ssl->conf->mfl_code );

    /* Check if a smaller max length was negotiated */
    if( ssl->session_out != NULL &&
        ssl_mfl_code_to_length( ssl->session_out->mfl_code ) < max_len )
    {
        max_len = ssl_mfl_code_to_length( ssl->session_out->mfl_code );
    }

    /* During a handshake, use the value being negotiated */
    if( ssl->session_negotiate != NULL &&
        ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code ) < max_len )
    {
        max_len = ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code );
    }

    return( max_len );
}

#if !defined(MBEDTLS_DEPRECATED_REMOVED)
size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl )
{
    return mbedtls_ssl_get_output_max_frag_len( ssl );
}
#endif /* !MBEDTLS_DEPRECATED_REMOVED */
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

#if defined(MBEDTLS_SSL_PROTO_DTLS)
size_t mbedtls_ssl_get_current_mtu( const mbedtls_ssl_context *ssl )
{
    /* Return unlimited mtu for client hello messages to avoid fragmentation. */
    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
        ( ssl->state == MBEDTLS_SSL_CLIENT_HELLO ||
          ssl->state == MBEDTLS_SSL_SERVER_HELLO ) )
        return ( 0 );

    if( ssl->handshake == NULL || ssl->handshake->mtu == 0 )
        return( ssl->mtu );

    if( ssl->mtu == 0 )
        return( ssl->handshake->mtu );

Coverage Report

Created: 2023-11-19 06:42