openssl/emssl-custom/rand.c

/*
 *
 *    Copyright (c) 2011-2015 Nest Labs, Inc.
 *    All rights reserved.
 *
 *    This document is the property of Nest. It is considered
 *    confidential and proprietary information.
 *
 *    This document may not be reproduced or transmitted in any form,
 *    in whole or in part, without the express written permission of
 *    Nest.
 *
 *    Description:
 *        Custom implemenation of OpenSSL's random number API that maps
 *        these functions onto the system's random number source (gCTRDRBG_ctx),
 *        which is an instance of the PolarSSL AES_CTR DRBG fed by the
 *        hardware random number source.
 */

#include <rand.h>
#include <openssl/rand.h>
#include <openssl/err.h>

extern int GetSecureRandomData(unsigned char *, uint16_t);

int RAND_bytes(unsigned char *buf, int num)
{
    int retval = 0, err;

    err = GetSecureRandomData(buf, num);

    if (err == 0)
    {
        retval = 1;
    }else{
        RANDerr(RAND_F_RAND_GET_RAND_METHOD, RAND_R_PRNG_ERROR);
    }

    return retval;
}

void RAND_add(const void *buf, int num, double entropy)
{
    /* Do nothing. This function is used to add additionaly entropy into the OpenSSL entropy pool.
     * In the context of Pumice, all entropy comes from the system hardware RNG, making this
     * function unnecessary.
     */
}

int RAND_pseudo_bytes(unsigned char *buf, int num)
{
    return RAND_bytes(buf, num);
}