crypto/rand/rand_lib.c

   1 /* crypto/rand/rand_lib.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include <stdio.h>
  60 #include <time.h>
  61 #include "cryptlib.h"
  62 #include <openssl/rand.h>
  63
  64 #ifndef OPENSSL_NO_ENGINE
  65 # include <openssl/engine.h>
  66 #endif
  67
  68 #ifdef OPENSSL_FIPS
  69 # include <openssl/fips.h>
  70 # include <openssl/fips_rand.h>
  71 #endif
  72
  73 #ifndef OPENSSL_NO_ENGINE
  74 /* non-NULL if default_RAND_meth is ENGINE-provided */
  75 static ENGINE *funct_ref = NULL;
  76 #endif
  77 static const RAND_METHOD *default_RAND_meth = NULL;
  78
  79 int RAND_set_rand_method(const RAND_METHOD *meth)
  80 {
  81 #ifndef OPENSSL_NO_ENGINE
  82     if (funct_ref) {
  83         ENGINE_finish(funct_ref);
  84         funct_ref = NULL;
  85     }
  86 #endif
  87     default_RAND_meth = meth;
  88     return 1;
  89 }
  90
  91 const RAND_METHOD *RAND_get_rand_method(void)
  92 {
  93     if (!default_RAND_meth) {
  94 #ifndef OPENSSL_NO_ENGINE
  95         ENGINE *e = ENGINE_get_default_RAND();
  96         if (e) {
  97             default_RAND_meth = ENGINE_get_RAND(e);
  98             if (!default_RAND_meth) {
  99                 ENGINE_finish(e);
 100                 e = NULL;
 101             }
 102         }
 103         if (e)
 104             funct_ref = e;
 105         else
 106 #endif
 107             default_RAND_meth = RAND_SSLeay();
 108     }
 109     return default_RAND_meth;
 110 }
 111
 112 #ifndef OPENSSL_NO_ENGINE
 113 int RAND_set_rand_engine(ENGINE *engine)
 114 {
 115     const RAND_METHOD *tmp_meth = NULL;
 116     if (engine) {
 117         if (!ENGINE_init(engine))
 118             return 0;
 119         tmp_meth = ENGINE_get_RAND(engine);
 120         if (!tmp_meth) {
 121             ENGINE_finish(engine);
 122             return 0;
 123         }
 124     }
 125     /* This function releases any prior ENGINE so call it first */
 126     RAND_set_rand_method(tmp_meth);
 127     funct_ref = engine;
 128     return 1;
 129 }
 130 #endif
 131
 132 void RAND_cleanup(void)
 133 {
 134     const RAND_METHOD *meth = RAND_get_rand_method();
 135     if (meth && meth->cleanup)
 136         meth->cleanup();
 137     RAND_set_rand_method(NULL);
 138 }
 139
 140 void RAND_seed(const void *buf, int num)
 141 {
 142     const RAND_METHOD *meth = RAND_get_rand_method();
 143     if (meth && meth->seed)
 144         meth->seed(buf, num);
 145 }
 146
 147 void RAND_add(const void *buf, int num, double entropy)
 148 {
 149     const RAND_METHOD *meth = RAND_get_rand_method();
 150     if (meth && meth->add)
 151         meth->add(buf, num, entropy);
 152 }
 153
 154 int RAND_bytes(unsigned char *buf, int num)
 155 {
 156     const RAND_METHOD *meth = RAND_get_rand_method();
 157     if (meth && meth->bytes)
 158         return meth->bytes(buf, num);
 159     return (-1);
 160 }
 161
 162 #ifndef OPENSSL_NO_DEPRECATED
 163 int RAND_pseudo_bytes(unsigned char *buf, int num)
 164 {
 165     const RAND_METHOD *meth = RAND_get_rand_method();
 166     if (meth && meth->pseudorand)
 167         return meth->pseudorand(buf, num);
 168     return (-1);
 169 }
 170 #endif
 171
 172 int RAND_status(void)
 173 {
 174     const RAND_METHOD *meth = RAND_get_rand_method();
 175     if (meth && meth->status)
 176         return meth->status();
 177     return 0;
 178 }
 179
 180 #ifdef OPENSSL_FIPS
 181
 182 /*
 183  * FIPS DRBG initialisation code. This sets up the DRBG for use by the rest
 184  * of OpenSSL.
 185  */
 186
 187 /*
 188  * Entropy gatherer: use standard OpenSSL PRNG to seed (this will gather
 189  * entropy internally through RAND_poll().
 190  */
 191
 192 static size_t drbg_get_entropy(DRBG_CTX *ctx, unsigned char **pout,
 193                                int entropy, size_t min_len, size_t max_len)
 194 {
 195     /* Round up request to multiple of block size */
 196     min_len = ((min_len + 19) / 20) * 20;
 197     *pout = OPENSSL_malloc(min_len);
 198     if (!*pout)
 199         return 0;
 200     if (RAND_SSLeay()->bytes(*pout, min_len) <= 0) {
 201         OPENSSL_free(*pout);
 202         *pout = NULL;
 203         return 0;
 204     }
 205     return min_len;
 206 }
 207
 208 static void drbg_free_entropy(DRBG_CTX *ctx, unsigned char *out, size_t olen)
 209 {
 210     if (out) {
 211         OPENSSL_cleanse(out, olen);
 212         OPENSSL_free(out);
 213     }
 214 }
 215
 216 /*
 217  * Set "additional input" when generating random data. This uses the current
 218  * PID, a time value and a counter.
 219  */
 220
 221 static size_t drbg_get_adin(DRBG_CTX *ctx, unsigned char **pout)
 222 {
 223     /* Use of static variables is OK as this happens under a lock */
 224     static unsigned char buf[16];
 225     static unsigned long counter;
 226     FIPS_get_timevec(buf, &counter);
 227     rand_hw_xor(buf, sizeof(buf));
 228     *pout = buf;
 229     return sizeof(buf);
 230 }
 231
 232 /*
 233  * RAND_add() and RAND_seed() pass through to OpenSSL PRNG so it is
 234  * correctly seeded by RAND_poll().
 235  */
 236
 237 static int drbg_rand_add(DRBG_CTX *ctx, const void *in, int inlen,
 238                          double entropy)
 239 {
 240     return RAND_SSLeay()->add(in, inlen, entropy);
 241 }
 242
 243 static int drbg_rand_seed(DRBG_CTX *ctx, const void *in, int inlen)
 244 {
 245     return RAND_SSLeay()->seed(in, inlen);
 246 }
 247
 248 int RAND_init_fips(void)
 249 {
 250     DRBG_CTX *dctx;
 251     size_t plen;
 252     unsigned char pers[32], *p;
 253     dctx = FIPS_get_default_drbg();
 254     FIPS_drbg_init(dctx, NID_aes_256_ctr, DRBG_FLAG_CTR_USE_DF);
 255     FIPS_drbg_set_callbacks(dctx,
 256                             drbg_get_entropy, drbg_free_entropy, 20,
 257                             drbg_get_entropy, drbg_free_entropy);
 258     FIPS_drbg_set_rand_callbacks(dctx, drbg_get_adin, 0,
 259                                  drbg_rand_seed, drbg_rand_add);
 260     /* Personalisation string: a string followed by date time vector */
 261     strcpy((char *)pers, "OpenSSL DRBG2.0");
 262     plen = drbg_get_adin(dctx, &p);
 263     memcpy(pers + 16, p, plen);
 264
 265     FIPS_drbg_instantiate(dctx, pers, sizeof(pers));
 266     FIPS_rand_set_method(FIPS_drbg_method());
 267     return 1;
 268 }
 269
 270 #endif