CSE2410 Fall 2014 Bounce

/* crypto/rand/rand_lib.c */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 * 

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 * 

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 * 

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from 

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 * 

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * 

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include <time.h>

#include "cryptlib.h"

#include <openssl/rand.h>

#ifndef OPENSSL_NO_ENGINE

#include <openssl/engine.h>

#endif

#ifdef OPENSSL_FIPS

#include <openssl/fips.h>

#include <openssl/fips_rand.h>

#include "rand_lcl.h"

#endif

#ifndef OPENSSL_NO_ENGINE

/* non-NULL if default_RAND_meth is ENGINE-provided */

static ENGINE *funct_ref =NULL;

#endif

static const RAND_METHOD *default_RAND_meth = NULL;

int RAND_set_rand_method(const RAND_METHOD *meth)

        {

#ifndef OPENSSL_NO_ENGINE

        if(funct_ref)

                {

                ENGINE_finish(funct_ref);

                funct_ref = NULL;

                }

#endif

        default_RAND_meth = meth;

        return 1;

        }

const RAND_METHOD *RAND_get_rand_method(void)

        {

        if (!default_RAND_meth)

                {

#ifndef OPENSSL_NO_ENGINE

                ENGINE *e = ENGINE_get_default_RAND();

                if(e)

                        {

                        default_RAND_meth = ENGINE_get_RAND(e);

                        if(!default_RAND_meth)

                                {

                                ENGINE_finish(e);

                                e = NULL;

                                }

                        }

                if(e)

                        funct_ref = e;

                else

#endif

                        default_RAND_meth = RAND_SSLeay();

                }

        return default_RAND_meth;

        }

#ifndef OPENSSL_NO_ENGINE

int RAND_set_rand_engine(ENGINE *engine)

        {

        const RAND_METHOD *tmp_meth = NULL;

        if(engine)

                {

                if(!ENGINE_init(engine))

                        return 0;

                tmp_meth = ENGINE_get_RAND(engine);

                if(!tmp_meth)

                        {

                        ENGINE_finish(engine);

                        return 0;

                        }

                }

        /* This function releases any prior ENGINE so call it first */

        RAND_set_rand_method(tmp_meth);

        funct_ref = engine;

        return 1;

        }

#endif

void RAND_cleanup(void)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->cleanup)

                meth->cleanup();

        RAND_set_rand_method(NULL);

        }

void RAND_seed(const void *buf, int num)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->seed)

                meth->seed(buf,num);

        }

void RAND_add(const void *buf, int num, double entropy)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->add)

                meth->add(buf,num,entropy);

        }

int RAND_bytes(unsigned char *buf, int num)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->bytes)

                return meth->bytes(buf,num);

        return(-1);

        }

int RAND_pseudo_bytes(unsigned char *buf, int num)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->pseudorand)

                return meth->pseudorand(buf,num);

        return(-1);

        }

int RAND_status(void)

        {

        const RAND_METHOD *meth = RAND_get_rand_method();

        if (meth && meth->status)

                return meth->status();

        return 0;

        }

#ifdef OPENSSL_FIPS

/* FIPS DRBG initialisation code. This sets up the DRBG for use by the

 * rest of OpenSSL. 

 */

/* Entropy gatherer: use standard OpenSSL PRNG to seed (this will gather

 * entropy internally through RAND_poll().

 */

static size_t drbg_get_entropy(DRBG_CTX *ctx, unsigned char **pout,

                                int entropy, size_t min_len, size_t max_len)

        {

        /* Round up request to multiple of block size */

        min_len = ((min_len + 19) / 20) * 20;

        *pout = OPENSSL_malloc(min_len);

        if (!*pout)

                return 0;

        if (ssleay_rand_bytes(*pout, min_len, 0, 0) <= 0)

                {

                OPENSSL_free(*pout);

                *pout = NULL;

                return 0;

                }

        return min_len;

        }

static void drbg_free_entropy(DRBG_CTX *ctx, unsigned char *out, size_t olen)

        {

        if (out)

                {

                OPENSSL_cleanse(out, olen);

                OPENSSL_free(out);

                }

        }

/* Set "additional input" when generating random data. This uses the

 * current PID, a time value and a counter.

 */

static size_t drbg_get_adin(DRBG_CTX *ctx, unsigned char **pout)

            {

        /* Use of static variables is OK as this happens under a lock */

        static unsigned char buf[16];

        static unsigned long counter;

        FIPS_get_timevec(buf, &counter);

        *pout = buf;

        return sizeof(buf);

        }

/* RAND_add() and RAND_seed() pass through to OpenSSL PRNG so it is 

 * correctly seeded by RAND_poll().

 */

static int drbg_rand_add(DRBG_CTX *ctx, const void *in, int inlen,

                                double entropy)

        {

        RAND_SSLeay()->add(in, inlen, entropy);

        return 1;

        }

static int drbg_rand_seed(DRBG_CTX *ctx, const void *in, int inlen)

        {

        RAND_SSLeay()->seed(in, inlen);

        return 1;

        }

#ifndef OPENSSL_DRBG_DEFAULT_TYPE

#define OPENSSL_DRBG_DEFAULT_TYPE        NID_aes_256_ctr

#endif

#ifndef OPENSSL_DRBG_DEFAULT_FLAGS

#define OPENSSL_DRBG_DEFAULT_FLAGS        DRBG_FLAG_CTR_USE_DF

#endif 

static int fips_drbg_type = OPENSSL_DRBG_DEFAULT_TYPE;

static int fips_drbg_flags = OPENSSL_DRBG_DEFAULT_FLAGS;

void RAND_set_fips_drbg_type(int type, int flags)

        {

        fips_drbg_type = type;

        fips_drbg_flags = flags;

        }

int RAND_init_fips(void)

        {

        DRBG_CTX *dctx;

        size_t plen;

        unsigned char pers[32], *p;

#ifndef OPENSSL_ALLOW_DUAL_EC_DRBG

        if (fips_drbg_type >> 16)

                {

                RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_DUAL_EC_DRBG_DISABLED);

                return 0;

                }

#endif

        dctx = FIPS_get_default_drbg();

        if (FIPS_drbg_init(dctx, fips_drbg_type, fips_drbg_flags) <= 0)

                {

                RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_ERROR_INITIALISING_DRBG);

                return 0;

                }

        FIPS_drbg_set_callbacks(dctx,

                                drbg_get_entropy, drbg_free_entropy, 20,

                                drbg_get_entropy, drbg_free_entropy);

        FIPS_drbg_set_rand_callbacks(dctx, drbg_get_adin, 0,

                                        drbg_rand_seed, drbg_rand_add);

        /* Personalisation string: a string followed by date time vector */

        strcpy((char *)pers, "OpenSSL DRBG2.0");

        plen = drbg_get_adin(dctx, &p);

        memcpy(pers + 16, p, plen);

        if (FIPS_drbg_instantiate(dctx, pers, sizeof(pers)) <= 0)

                {

                RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_ERROR_INSTANTIATING_DRBG);

                return 0;

                }

        FIPS_rand_set_method(FIPS_drbg_method());

        return 1;

        }

#endif