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fips_rand.c

/* ====================================================================
 * Copyright (c) 2007 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/*
 * This is a FIPS approved AES PRNG based on ANSI X9.31 A.2.4.
 */

#include "e_os.h"

/* If we don't define _XOPEN_SOURCE_EXTENDED, struct timeval won't
   be defined and gettimeofday() won't be declared with strict compilers
   like DEC C in ANSI C mode.  */
#ifndef _XOPEN_SOURCE_EXTENDED
#define _XOPEN_SOURCE_EXTENDED 1
#endif

#include <openssl/rand.h>
#include <openssl/aes.h>
#include <openssl/err.h>
#include <openssl/fips_rand.h>
#ifndef OPENSSL_SYS_WIN32
#include <sys/time.h>
#endif
#include <assert.h>
#ifndef OPENSSL_SYS_WIN32
# ifdef OPENSSL_UNISTD
#  include OPENSSL_UNISTD
# else
#  include <unistd.h>
# endif
#endif
#include <string.h>
#include <openssl/fips.h>
#include "fips_locl.h"

#ifdef OPENSSL_FIPS

void *OPENSSL_stderr(void);

#define AES_BLOCK_LENGTH      16


/* AES FIPS PRNG implementation */

typedef struct 
      {
      int seeded;
      int keyed;
      int test_mode;
      int second;
      int error;
      unsigned long counter;
      AES_KEY ks;
      int vpos;
      /* Temporary storage for key if it equals seed length */
      unsigned char tmp_key[AES_BLOCK_LENGTH];
      unsigned char V[AES_BLOCK_LENGTH];
      unsigned char DT[AES_BLOCK_LENGTH];
      unsigned char last[AES_BLOCK_LENGTH];
      } FIPS_PRNG_CTX;

static FIPS_PRNG_CTX sctx;

static int fips_prng_fail = 0;

void FIPS_rng_stick(void)
      {
      fips_prng_fail = 1;
      }

static void fips_rand_prng_reset(FIPS_PRNG_CTX *ctx)
      {
      ctx->seeded = 0;
      ctx->keyed = 0;
      ctx->test_mode = 0;
      ctx->counter = 0;
      ctx->second = 0;
      ctx->error = 0;
      ctx->vpos = 0;
      OPENSSL_cleanse(ctx->V, AES_BLOCK_LENGTH);
      OPENSSL_cleanse(&ctx->ks, sizeof(AES_KEY));
      }
      

static int fips_set_prng_key(FIPS_PRNG_CTX *ctx,
                  const unsigned char *key, FIPS_RAND_SIZE_T keylen)
      {
      FIPS_selftest_check();
      if (keylen != 16 && keylen != 24 && keylen != 32)
            {
            /* error: invalid key size */
            return 0;
            }
      AES_set_encrypt_key(key, keylen << 3, &ctx->ks);
      if (keylen == 16)
            {
            memcpy(ctx->tmp_key, key, 16);
            ctx->keyed = 2;
            }
      else
            ctx->keyed = 1;
      ctx->seeded = 0;
      ctx->second = 0;
      return 1;
      }

static int fips_set_prng_seed(FIPS_PRNG_CTX *ctx,
                  const unsigned char *seed, FIPS_RAND_SIZE_T seedlen)
      {
      int i;
      if (!ctx->keyed)
            return 0;
      /* In test mode seed is just supplied data */
      if (ctx->test_mode)
            {
            if (seedlen != AES_BLOCK_LENGTH)
                  return 0;
            memcpy(ctx->V, seed, AES_BLOCK_LENGTH);
            ctx->seeded = 1;
            return 1;
            }
      /* Outside test mode XOR supplied data with existing seed */
      for (i = 0; i < seedlen; i++)
            {
            ctx->V[ctx->vpos++] ^= seed[i];
            if (ctx->vpos == AES_BLOCK_LENGTH)
                  {
                  ctx->vpos = 0;
                  /* Special case if first seed and key length equals
                   * block size check key and seed do not match.
                   */ 
                  if (ctx->keyed == 2)
                        {
                        if (!memcmp(ctx->tmp_key, ctx->V, 16))
                              {
                              RANDerr(RAND_F_FIPS_SET_PRNG_SEED,
                                    RAND_R_PRNG_SEED_MUST_NOT_MATCH_KEY);
                              return 0;
                              }
                        OPENSSL_cleanse(ctx->tmp_key, 16);
                        ctx->keyed = 1;
                        }
                  ctx->seeded = 1;
                  }
            }
      return 1;
      }

static int fips_set_test_mode(FIPS_PRNG_CTX *ctx)
      {
      if (ctx->keyed)
            {
            RANDerr(RAND_F_FIPS_SET_TEST_MODE,RAND_R_PRNG_KEYED);
            return 0;
            }
      ctx->test_mode = 1;
      return 1;
      }

int FIPS_rand_test_mode(void)
      {
      return fips_set_test_mode(&sctx);
      }

int FIPS_rand_set_dt(unsigned char *dt)
      {
      if (!sctx.test_mode)
            {
            RANDerr(RAND_F_FIPS_RAND_SET_DT,RAND_R_NOT_IN_TEST_MODE);
            return 0;
            }
      memcpy(sctx.DT, dt, AES_BLOCK_LENGTH);
      return 1;
      }

static void fips_get_dt(FIPS_PRNG_CTX *ctx)
    {
#ifdef OPENSSL_SYS_WIN32
      FILETIME ft;
#else
      struct timeval tv;
#endif
      unsigned char *buf = ctx->DT;

#ifndef GETPID_IS_MEANINGLESS
      unsigned long pid;
#endif

#ifdef OPENSSL_SYS_WIN32
      GetSystemTimeAsFileTime(&ft);
      buf[0] = (unsigned char) (ft.dwHighDateTime & 0xff);
      buf[1] = (unsigned char) ((ft.dwHighDateTime >> 8) & 0xff);
      buf[2] = (unsigned char) ((ft.dwHighDateTime >> 16) & 0xff);
      buf[3] = (unsigned char) ((ft.dwHighDateTime >> 24) & 0xff);
      buf[4] = (unsigned char) (ft.dwLowDateTime & 0xff);
      buf[5] = (unsigned char) ((ft.dwLowDateTime >> 8) & 0xff);
      buf[6] = (unsigned char) ((ft.dwLowDateTime >> 16) & 0xff);
      buf[7] = (unsigned char) ((ft.dwLowDateTime >> 24) & 0xff);
#else
      gettimeofday(&tv,NULL);
      buf[0] = (unsigned char) (tv.tv_sec & 0xff);
      buf[1] = (unsigned char) ((tv.tv_sec >> 8) & 0xff);
      buf[2] = (unsigned char) ((tv.tv_sec >> 16) & 0xff);
      buf[3] = (unsigned char) ((tv.tv_sec >> 24) & 0xff);
      buf[4] = (unsigned char) (tv.tv_usec & 0xff);
      buf[5] = (unsigned char) ((tv.tv_usec >> 8) & 0xff);
      buf[6] = (unsigned char) ((tv.tv_usec >> 16) & 0xff);
      buf[7] = (unsigned char) ((tv.tv_usec >> 24) & 0xff);
#endif
      buf[8] = (unsigned char) (ctx->counter & 0xff);
      buf[9] = (unsigned char) ((ctx->counter >> 8) & 0xff);
      buf[10] = (unsigned char) ((ctx->counter >> 16) & 0xff);
      buf[11] = (unsigned char) ((ctx->counter >> 24) & 0xff);

      ctx->counter++;


#ifndef GETPID_IS_MEANINGLESS
      pid=(unsigned long)getpid();
      buf[12] = (unsigned char) (pid & 0xff);
      buf[13] = (unsigned char) ((pid >> 8) & 0xff);
      buf[14] = (unsigned char) ((pid >> 16) & 0xff);
      buf[15] = (unsigned char) ((pid >> 24) & 0xff);
#endif
    }

static int fips_rand(FIPS_PRNG_CTX *ctx,
                  unsigned char *out, FIPS_RAND_SIZE_T outlen)
      {
      unsigned char R[AES_BLOCK_LENGTH], I[AES_BLOCK_LENGTH];
      unsigned char tmp[AES_BLOCK_LENGTH];
      int i;
      if (ctx->error)
            {
            RANDerr(RAND_F_FIPS_RAND,RAND_R_PRNG_ERROR);
            return 0;
            }
      if (!ctx->keyed)
            {
            RANDerr(RAND_F_FIPS_RAND,RAND_R_NO_KEY_SET);
            return 0;
            }
      if (!ctx->seeded)
            {
            RANDerr(RAND_F_FIPS_RAND,RAND_R_PRNG_NOT_SEEDED);
            return 0;
            }
      for (;;)
            {
            if (!ctx->test_mode)
                  fips_get_dt(ctx);
            AES_encrypt(ctx->DT, I, &ctx->ks);
            for (i = 0; i < AES_BLOCK_LENGTH; i++)
                  tmp[i] = I[i] ^ ctx->V[i];
            AES_encrypt(tmp, R, &ctx->ks);
            for (i = 0; i < AES_BLOCK_LENGTH; i++)
                  tmp[i] = R[i] ^ I[i];
            AES_encrypt(tmp, ctx->V, &ctx->ks);
            /* Continuous PRNG test */
            if (ctx->second)
                  {
                  if (fips_prng_fail)
                        memcpy(ctx->last, R, AES_BLOCK_LENGTH);
                  if (!memcmp(R, ctx->last, AES_BLOCK_LENGTH))
                        {
                        RANDerr(RAND_F_FIPS_RAND,RAND_R_PRNG_STUCK);
                        ctx->error = 1;
                        fips_set_selftest_fail();
                        return 0;
                        }
                  }
            memcpy(ctx->last, R, AES_BLOCK_LENGTH);
            if (!ctx->second)
                  {
                  ctx->second = 1;
                  if (!ctx->test_mode)
                        continue;
                  }

            if (outlen <= AES_BLOCK_LENGTH)
                  {
                  memcpy(out, R, outlen);
                  break;
                  }

            memcpy(out, R, AES_BLOCK_LENGTH);
            out += AES_BLOCK_LENGTH;
            outlen -= AES_BLOCK_LENGTH;
            }
      return 1;
      }


int FIPS_rand_set_key(const unsigned char *key, FIPS_RAND_SIZE_T keylen)
      {
      int ret;
      CRYPTO_w_lock(CRYPTO_LOCK_RAND);
      ret = fips_set_prng_key(&sctx, key, keylen);
      CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
      return ret;
      }

int FIPS_rand_seed(const void *seed, FIPS_RAND_SIZE_T seedlen)
      {
      int ret;
      CRYPTO_w_lock(CRYPTO_LOCK_RAND);
      ret = fips_set_prng_seed(&sctx, seed, seedlen);
      CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
      return ret;
      }


int FIPS_rand_bytes(unsigned char *out, FIPS_RAND_SIZE_T count)
      {
      int ret;
      CRYPTO_w_lock(CRYPTO_LOCK_RAND);
      ret = fips_rand(&sctx, out, count);
      CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
      return ret;
      }

int FIPS_rand_status(void)
      {
      int ret;
      CRYPTO_r_lock(CRYPTO_LOCK_RAND);
      ret = sctx.seeded;
      CRYPTO_r_unlock(CRYPTO_LOCK_RAND);
      return ret;
      }

void FIPS_rand_reset(void)
      {
      CRYPTO_w_lock(CRYPTO_LOCK_RAND);
      fips_rand_prng_reset(&sctx);
      CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
      }

static void fips_do_rand_seed(const void *seed, FIPS_RAND_SIZE_T seedlen)
      {
      FIPS_rand_seed(seed, seedlen);
      }

static void fips_do_rand_add(const void *seed, FIPS_RAND_SIZE_T seedlen,
                              double add_entropy)
      {
      FIPS_rand_seed(seed, seedlen);
      }

static const RAND_METHOD rand_fips_meth=
    {
    fips_do_rand_seed,
    FIPS_rand_bytes,
    FIPS_rand_reset,
    fips_do_rand_add,
    FIPS_rand_bytes,
    FIPS_rand_status
    };

const RAND_METHOD *FIPS_rand_method(void)
{
  return &rand_fips_meth;
}

#endif

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