2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006, 2012 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
23 * @file util/crypto_random.c
24 * @brief functions to gather random numbers
25 * @author Christian Grothoff
28 #include "gnunet_common.h"
29 #include "gnunet_crypto_lib.h"
30 #include "gnunet_os_lib.h"
33 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
35 #define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
38 /* TODO: ndurner, move this to plibc? */
39 /* The code is derived from glibc, obviously */
47 #define RANDOM() glibc_weak_rand32()
48 #define SRANDOM(s) glibc_weak_srand32(s)
52 #define RAND_MAX 0x7fffffff /* Hopefully this is correct */
55 static int32_t glibc_weak_rand32_state = 1;
59 glibc_weak_srand32 (int32_t s)
61 glibc_weak_rand32_state = s;
68 int32_t val = glibc_weak_rand32_state;
70 val = ((glibc_weak_rand32_state * 1103515245) + 12345) & 0x7fffffff;
71 glibc_weak_rand32_state = val;
77 * Create a cryptographically weak pseudo-random number in the interval of 0 to 1.
79 * @return number between 0 and 1.
84 return ((double) RANDOM () / RAND_MAX);
89 * Seed a weak random generator. Only GNUNET_CRYPTO_QUALITY_WEAK-mode generator
92 * @param seed the seed to use
95 GNUNET_CRYPTO_seed_weak_random (int32_t seed)
102 * Produce a random value.
104 * @param mode desired quality of the random number
105 * @param i the upper limit (exclusive) for the random number
106 * @return a random value in the interval [0,i[.
109 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i)
111 #ifdef gcry_fast_random_poll
112 static unsigned int invokeCount;
117 GNUNET_assert (i > 0);
121 case GNUNET_CRYPTO_QUALITY_STRONG:
122 /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */
123 #ifdef gcry_fast_random_poll
124 if ((invokeCount++ % 256) == 0)
125 gcry_fast_random_poll ();
127 ul = UINT32_MAX - (UINT32_MAX % i);
130 gcry_randomize ((unsigned char *) &ret, sizeof (uint32_t),
135 case GNUNET_CRYPTO_QUALITY_NONCE:
136 ul = UINT32_MAX - (UINT32_MAX % i);
139 gcry_create_nonce (&ret, sizeof (ret));
143 case GNUNET_CRYPTO_QUALITY_WEAK:
144 ret = i * get_weak_random ();
156 * Get an array with a random permutation of the
158 * @param mode GNUNET_RANDOM_QUALITY_STRONG if the strong (but expensive)
159 * PRNG should be used, GNUNET_RANDOM_QUALITY_WEAK otherwise
160 * @param n the size of the array
161 * @return the permutation array (allocated from heap)
164 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n)
171 GNUNET_assert (n > 0);
172 ret = GNUNET_malloc (n * sizeof (unsigned int));
173 for (i = 0; i < n; i++)
175 for (i = n - 1; i > 0; i--)
177 x = GNUNET_CRYPTO_random_u32 (mode, i + 1);
186 * Random on unsigned 64-bit values.
189 * @param mode desired quality of the random number
190 * @param max value returned will be in range [0,max) (exclusive)
191 * @return random 64-bit number
194 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max)
199 GNUNET_assert (max > 0);
202 case GNUNET_CRYPTO_QUALITY_STRONG:
203 ul = UINT64_MAX - (UINT64_MAX % max);
206 gcry_randomize ((unsigned char *) &ret, sizeof (uint64_t),
211 case GNUNET_CRYPTO_QUALITY_NONCE:
212 ul = UINT64_MAX - (UINT64_MAX % max);
215 gcry_create_nonce (&ret, sizeof (ret));
220 case GNUNET_CRYPTO_QUALITY_WEAK:
221 ret = max * get_weak_random ();
233 * Process ID of the "find" process that we use for
236 static struct GNUNET_OS_Process *genproc;
240 * Function called by libgcrypt whenever we are
241 * blocked gathering entropy.
244 entropy_generator (void *cls, const char *what, int printchar, int current,
248 enum GNUNET_OS_ProcessStatusType type;
251 if (0 != strcmp (what, "need_entropy"))
253 if (current == total)
257 if (0 != GNUNET_OS_process_kill (genproc, SIGKILL))
258 LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill");
259 GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc));
260 GNUNET_OS_process_destroy (genproc);
267 ret = GNUNET_OS_process_status (genproc, &type, &code);
268 if (ret == GNUNET_NO)
269 return; /* still running */
270 if (ret == GNUNET_SYSERR)
275 if (0 != GNUNET_OS_process_kill (genproc, SIGKILL))
276 LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill");
277 GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc));
278 GNUNET_OS_process_destroy (genproc);
281 LOG (GNUNET_ERROR_TYPE_INFO, _("Starting `%s' process to generate entropy\n"),
284 GNUNET_OS_start_process (GNUNET_NO, 0,
285 NULL, NULL, "sh", "sh", "-c",
286 "exec find / -mount -type f -exec cp {} /dev/null \\; 2>/dev/null",
296 GNUNET_OS_process_kill (genproc, SIGKILL);
297 GNUNET_OS_process_destroy (genproc);
303 void __attribute__ ((constructor))
304 GNUNET_CRYPTO_random_init ()
308 if (! gcry_check_version (NEED_LIBGCRYPT_VERSION))
312 ("libgcrypt has not the expected version (version %s is required).\n"),
313 NEED_LIBGCRYPT_VERSION);
316 if ((rc = gcry_control (GCRYCTL_DISABLE_SECMEM, 0)))
317 FPRINTF (stderr, "Failed to set libgcrypt option %s: %s\n", "DISABLE_SECMEM",
319 /* we only generate ephemeral keys in-process; for those,
320 we are fine with "just" using GCRY_STRONG_RANDOM */
321 if ((rc = gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0)))
322 FPRINTF (stderr, "Failed to set libgcrypt option %s: %s\n", "ENABLE_QUICK_RANDOM",
325 #ifdef GCRYCTL_INITIALIZATION_FINISHED
326 gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
328 #ifdef gcry_fast_random_poll
329 gcry_fast_random_poll ();
331 gcry_set_progress_handler (&entropy_generator, NULL);
333 GNUNET_CRYPTO_seed_weak_random (time (NULL) ^
334 GNUNET_CRYPTO_random_u32
335 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX));
339 void __attribute__ ((destructor))
340 GNUNET_CRYPTO_random_fini ()
342 gcry_set_progress_handler (NULL, NULL);
347 /* end of crypto_random.c */