lib/hcrypto/rand.c

   1 /*
   2  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <config.h>
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <rand.h>
  41 #include <randi.h>
  42
  43 #include <roken.h>
  44
  45 #ifndef O_BINARY
  46 #define O_BINARY 0
  47 #endif
  48
  49 #ifdef _WIN32
  50 #include<shlobj.h>
  51 #endif
  52
  53 /**
  54  * @page page_rand RAND - random number
  55  *
  56  * See the library functions here: @ref hcrypto_rand
  57  */
  58
  59 const static RAND_METHOD *selected_meth = NULL;
  60 static ENGINE *selected_engine = NULL;
  61
  62 static void
  63 init_method(void)
  64 {
  65     if (selected_meth != NULL)
  66         return;
  67 #if defined(_WIN32)
  68     selected_meth = &hc_rand_w32crypto_method;
  69 #elif defined(__APPLE__)
  70     selected_meth = &hc_rand_unix_method;
  71 #else
  72     selected_meth = &hc_rand_fortuna_method;
  73 #endif
  74 }
  75
  76 /**
  77  * Seed that random number generator. Secret material can securely be
  78  * feed into the function, they will never be returned.
  79  *
  80  * @param indata seed data
  81  * @param size length seed data
  82  *
  83  * @ingroup hcrypto_rand
  84  */
  85
  86 void
  87 RAND_seed(const void *indata, size_t size)
  88 {
  89     init_method();
  90     (*selected_meth->seed)(indata, size);
  91 }
  92
  93 /**
  94  * Get a random block from the random generator, can be used for key material.
  95  *
  96  * @param outdata random data
  97  * @param size length random data
  98  *
  99  * @return 1 on success, 0 on failure.
 100  *
 101  * @ingroup hcrypto_rand
 102  */
 103 int
 104 RAND_bytes(void *outdata, size_t size)
 105 {
 106     if (size == 0)
 107         return 1;
 108     init_method();
 109     return (*selected_meth->bytes)(outdata, size);
 110 }
 111
 112 /**
 113  * Reset and free memory used by the random generator.
 114  *
 115  * @ingroup hcrypto_rand
 116  */
 117
 118 void
 119 RAND_cleanup(void)
 120 {
 121     const RAND_METHOD *meth = selected_meth;
 122     ENGINE *engine = selected_engine;
 123
 124     selected_meth = NULL;
 125     selected_engine = NULL;
 126
 127     if (meth)
 128         (*meth->cleanup)();
 129     if (engine)
 130         ENGINE_finish(engine);
 131 }
 132
 133 /**
 134  * Seed that random number generator. Secret material can securely be
 135  * feed into the function, they will never be returned.
 136  *
 137  * @param indata the input data.
 138  * @param size size of in data.
 139  * @param entropi entropi in data.
 140  *
 141  *
 142  * @ingroup hcrypto_rand
 143  */
 144
 145 void
 146 RAND_add(const void *indata, size_t size, double entropi)
 147 {
 148     init_method();
 149     (*selected_meth->add)(indata, size, entropi);
 150 }
 151
 152 /**
 153  * Get a random block from the random generator, should NOT be used for key material.
 154  *
 155  * @param outdata random data
 156  * @param size length random data
 157  *
 158  * @return 1 on success, 0 on failure.
 159  *
 160  * @ingroup hcrypto_rand
 161  */
 162
 163 int
 164 RAND_pseudo_bytes(void *outdata, size_t size)
 165 {
 166     init_method();
 167     return (*selected_meth->pseudorand)(outdata, size);
 168 }
 169
 170 /**
 171  * Return status of the random generator
 172  *
 173  * @return 1 if the random generator can deliver random data.
 174  *
 175  * @ingroup hcrypto_rand
 176  */
 177
 178 int
 179 RAND_status(void)
 180 {
 181     init_method();
 182     return (*selected_meth->status)();
 183 }
 184
 185 /**
 186  * Set the default random method.
 187  *
 188  * @param meth set the new default method.
 189  *
 190  * @return 1 on success.
 191  *
 192  * @ingroup hcrypto_rand
 193  */
 194
 195 int
 196 RAND_set_rand_method(const RAND_METHOD *meth)
 197 {
 198     const RAND_METHOD *old = selected_meth;
 199     selected_meth = meth;
 200     if (old)
 201         (*old->cleanup)();
 202     if (selected_engine) {
 203         ENGINE_finish(selected_engine);
 204         selected_engine = NULL;
 205     }
 206     return 1;
 207 }
 208
 209 /**
 210  * Get the default random method.
 211  *
 212  * @ingroup hcrypto_rand
 213  */
 214
 215 const RAND_METHOD *
 216 RAND_get_rand_method(void)
 217 {
 218     init_method();
 219     return selected_meth;
 220 }
 221
 222 /**
 223  * Set the default random method from engine.
 224  *
 225  * @param engine use engine, if NULL is passed it, old method and engine is cleared.
 226  *
 227  * @return 1 on success, 0 on failure.
 228  *
 229  * @ingroup hcrypto_rand
 230  */
 231
 232 int
 233 RAND_set_rand_engine(ENGINE *engine)
 234 {
 235     const RAND_METHOD *meth, *old = selected_meth;
 236
 237     if (engine) {
 238         ENGINE_up_ref(engine);
 239         meth = ENGINE_get_RAND(engine);
 240         if (meth == NULL) {
 241             ENGINE_finish(engine);
 242             return 0;
 243         }
 244     } else {
 245         meth = NULL;
 246     }
 247
 248     if (old)
 249         (*old->cleanup)();
 250
 251     if (selected_engine)
 252         ENGINE_finish(selected_engine);
 253
 254     selected_engine = engine;
 255     selected_meth = meth;
 256
 257     return 1;
 258 }
 259
 260 #define RAND_FILE_SIZE 1024
 261
 262 /**
 263  * Load a a file and feed it into RAND_seed().
 264  *
 265  * @param filename name of file to read.
 266  * @param size minimum size to read.
 267  *
 268  * @ingroup hcrypto_rand
 269  */
 270
 271 int
 272 RAND_load_file(const char *filename, size_t size)
 273 {
 274     unsigned char buf[128];
 275     size_t len;
 276     ssize_t slen;
 277     int fd;
 278
 279     fd = open(filename, O_RDONLY | O_BINARY, 0600);
 280     if (fd < 0)
 281         return 0;
 282     rk_cloexec(fd);
 283     len = 0;
 284     while(len < size) {
 285         slen = read(fd, buf, sizeof(buf));
 286         if (slen <= 0)
 287             break;
 288         RAND_seed(buf, slen);
 289         len += slen;
 290     }
 291     close(fd);
 292
 293     return len ? 1 : 0;
 294 }
 295
 296 /**
 297  * Write of random numbers to a file to store for later initiation with RAND_load_file().
 298  *
 299  * @param filename name of file to write.
 300  *
 301  * @return 1 on success and non-one on failure.
 302  * @ingroup hcrypto_rand
 303  */
 304
 305 int
 306 RAND_write_file(const char *filename)
 307 {
 308     unsigned char buf[128];
 309     size_t len;
 310     int res = 0, fd;
 311
 312     fd = open(filename, O_WRONLY | O_CREAT | O_BINARY, 0600);
 313     if (fd < 0)
 314         return 0;
 315     rk_cloexec(fd);
 316
 317     len = 0;
 318     while(len < RAND_FILE_SIZE) {
 319         res = RAND_bytes(buf, sizeof(buf));
 320         if (res != 1)
 321             break;
 322         if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
 323             res = 0;
 324             break;
 325         }
 326         len += sizeof(buf);
 327     }
 328
 329     close(fd);
 330
 331     return res;
 332 }
 333
 334 /**
 335  * Return the default random state filename for a user to use for
 336  * RAND_load_file(), and RAND_write_file().
 337  *
 338  * @param filename buffer to hold file name.
 339  * @param size size of buffer filename.
 340  *
 341  * @return the buffer filename or NULL on failure.
 342  *
 343  * @ingroup hcrypto_rand
 344  */
 345
 346 const char *
 347 RAND_file_name(char *filename, size_t size)
 348 {
 349     const char *e = NULL;
 350     int pathp = 0, ret;
 351
 352     if (!issuid()) {
 353         e = getenv("RANDFILE");
 354         if (e == NULL)
 355             e = getenv("HOME");
 356         if (e)
 357             pathp = 1;
 358     }
 359
 360 #ifndef _WIN32
 361     /*
 362      * Here we really want to call getpwuid(getuid()) but this will
 363      * cause recursive lookups if the nss library uses
 364      * gssapi/krb5/hcrypto to authenticate to the ldap servers.
 365      *
 366      * So at least return the unix /dev/random if we have one
 367      */
 368     if (e == NULL) {
 369         int fd;
 370
 371         fd = _hc_unix_device_fd(O_RDONLY, &e);
 372         if (fd >= 0)
 373             close(fd);
 374     }
 375 #else  /* Win32 */
 376
 377     if (e == NULL) {
 378         char profile[MAX_PATH];
 379
 380         if (SHGetFolderPath(NULL, CSIDL_LOCAL_APPDATA, NULL,
 381                             SHGFP_TYPE_CURRENT, profile) == S_OK) {
 382             ret = snprintf(filename, size, "%s\\.rnd", profile);
 383
 384             if (ret > 0 && ret < size)
 385                 return filename;
 386         }
 387     }
 388
 389 #endif
 390
 391     if (e == NULL)
 392         return NULL;
 393
 394     if (pathp)
 395         ret = snprintf(filename, size, "%s/.rnd", e);
 396     else
 397         ret = snprintf(filename, size, "%s", e);
 398
 399     if (ret <= 0 || ret >= size)
 400         return NULL;
 401
 402     return filename;
 403 }