aboutsummaryrefslogtreecommitdiff
path: root/src/util/crypto_random.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/util/crypto_random.c')
-rw-r--r--src/util/crypto_random.c334
1 files changed, 334 insertions, 0 deletions
diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c
new file mode 100644
index 0000000..25226a3
--- /dev/null
+++ b/src/util/crypto_random.c
@@ -0,0 +1,334 @@
+/*
+ This file is part of GNUnet.
+ (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors)
+
+ GNUnet is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 2, or (at your
+ option) any later version.
+
+ GNUnet is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNUnet; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+
+*/
+
+/**
+ * @file util/crypto_random.c
+ * @brief functions to gather random numbers
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_os_lib.h"
+#include <gcrypt.h>
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
+
+/* TODO: ndurner, move this to plibc? */
+/* The code is derived from glibc, obviously */
+#if MINGW
+#ifdef RANDOM
+#undef RANDOM
+#endif
+#ifdef SRANDOM
+#undef SRANDOM
+#endif
+#define RANDOM() glibc_weak_rand32()
+#define SRANDOM(s) glibc_weak_srand32(s)
+static int32_t glibc_weak_rand32_state = 1;
+
+void
+glibc_weak_srand32 (int32_t s)
+{
+ glibc_weak_rand32_state = s;
+}
+
+int32_t
+glibc_weak_rand32 ()
+{
+ int32_t val = glibc_weak_rand32_state;
+
+ val = ((glibc_weak_rand32_state * 1103515245) + 12345) & 0x7fffffff;
+ glibc_weak_rand32_state = val;
+ return val;
+}
+#endif
+
+/**
+ * Create a cryptographically weak pseudo-random number in the interval of 0 to 1.
+ *
+ * @return number between 0 and 1.
+ */
+static double
+weak_random ()
+{
+ return ((double) RANDOM () / RAND_MAX);
+}
+
+/**
+ * Seed a weak random generator. Only GNUNET_CRYPTO_QUALITY_WEAK-mode generator
+ * can be seeded.
+ *
+ * @param seed the seed to use
+ */
+void
+GNUNET_CRYPTO_seed_weak_random (int32_t seed)
+{
+ SRANDOM (seed);
+}
+
+/**
+ * Produce a random value.
+ *
+ * @param mode desired quality of the random number
+ * @param i the upper limit (exclusive) for the random number
+ * @return a random value in the interval [0,i[.
+ */
+uint32_t
+GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i)
+{
+#ifdef gcry_fast_random_poll
+ static unsigned int invokeCount;
+#endif
+ uint32_t ret;
+ uint32_t ul;
+
+ GNUNET_assert (i > 0);
+
+ switch (mode)
+ {
+ case GNUNET_CRYPTO_QUALITY_STRONG:
+ /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */
+#ifdef gcry_fast_random_poll
+ if ((invokeCount++ % 256) == 0)
+ gcry_fast_random_poll ();
+#endif
+ ul = UINT32_MAX - (UINT32_MAX % i);
+ do
+ {
+ gcry_randomize ((unsigned char *) &ret, sizeof (uint32_t),
+ GCRY_STRONG_RANDOM);
+ }
+ while (ret >= ul);
+ return ret % i;
+ case GNUNET_CRYPTO_QUALITY_NONCE:
+ ul = UINT32_MAX - (UINT32_MAX % i);
+ do
+ {
+ gcry_create_nonce (&ret, sizeof (ret));
+ }
+ while (ret >= ul);
+ return ret % i;
+ case GNUNET_CRYPTO_QUALITY_WEAK:
+ ret = i * weak_random ();
+ if (ret >= i)
+ ret = i - 1;
+ return ret;
+ default:
+ GNUNET_assert (0);
+ }
+ return 0;
+}
+
+
+/**
+ * Get an array with a random permutation of the
+ * numbers 0...n-1.
+ * @param mode GNUNET_RANDOM_QUALITY_STRONG if the strong (but expensive)
+ * PRNG should be used, GNUNET_RANDOM_QUALITY_WEAK otherwise
+ * @param n the size of the array
+ * @return the permutation array (allocated from heap)
+ */
+unsigned int *
+GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n)
+{
+ unsigned int *ret;
+ unsigned int i;
+ unsigned int tmp;
+ uint32_t x;
+
+ GNUNET_assert (n > 0);
+ ret = GNUNET_malloc (n * sizeof (unsigned int));
+ for (i = 0; i < n; i++)
+ ret[i] = i;
+ for (i = n - 1; i > 0; i--)
+ {
+ x = GNUNET_CRYPTO_random_u32 (mode, i + 1);
+ tmp = ret[x];
+ ret[x] = ret[i];
+ ret[i] = tmp;
+ }
+ return ret;
+}
+
+/**
+ * Random on unsigned 64-bit values.
+ *
+ *
+ * @param mode desired quality of the random number
+ * @param max value returned will be in range [0,max) (exclusive)
+ * @return random 64-bit number
+ */
+uint64_t
+GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max)
+{
+ uint64_t ret;
+ uint64_t ul;
+
+ GNUNET_assert (max > 0);
+ switch (mode)
+ {
+ case GNUNET_CRYPTO_QUALITY_STRONG:
+ ul = UINT64_MAX - (UINT64_MAX % max);
+ do
+ {
+ gcry_randomize ((unsigned char *) &ret, sizeof (uint64_t),
+ GCRY_STRONG_RANDOM);
+ }
+ while (ret >= ul);
+ return ret % max;
+ case GNUNET_CRYPTO_QUALITY_NONCE:
+ ul = UINT64_MAX - (UINT64_MAX % max);
+ do
+ {
+ gcry_create_nonce (&ret, sizeof (ret));
+ }
+ while (ret >= ul);
+
+ return ret % max;
+ case GNUNET_CRYPTO_QUALITY_WEAK:
+ ret = max * weak_random ();
+ if (ret >= max)
+ ret = max - 1;
+ return ret;
+ default:
+ GNUNET_assert (0);
+ }
+ return 0;
+}
+
+/**
+ * This function should only be called in testcases
+ * where strong entropy gathering is not desired
+ * (for example, for hostkey generation).
+ */
+void
+GNUNET_CRYPTO_random_disable_entropy_gathering ()
+{
+ gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
+}
+
+
+/**
+ * Process ID of the "find" process that we use for
+ * entropy gathering.
+ */
+static struct GNUNET_OS_Process *genproc;
+
+/**
+ * Function called by libgcrypt whenever we are
+ * blocked gathering entropy.
+ */
+static void
+entropy_generator (void *cls, const char *what, int printchar, int current,
+ int total)
+{
+ unsigned long code;
+ enum GNUNET_OS_ProcessStatusType type;
+ int ret;
+
+ if (0 != strcmp (what, "need_entropy"))
+ return;
+ if (current == total)
+ {
+ if (genproc != NULL)
+ {
+ if (0 != GNUNET_OS_process_kill (genproc, SIGTERM))
+ LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill");
+ GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc));
+ GNUNET_OS_process_close (genproc);
+ genproc = NULL;
+ }
+ return;
+ }
+ if (genproc != NULL)
+ {
+ ret = GNUNET_OS_process_status (genproc, &type, &code);
+ if (ret == GNUNET_NO)
+ return; /* still running */
+ if (ret == GNUNET_SYSERR)
+ {
+ GNUNET_break (0);
+ return;
+ }
+ if (0 != GNUNET_OS_process_kill (genproc, SIGTERM))
+ LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "kill");
+ GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc));
+ GNUNET_OS_process_close (genproc);
+ genproc = NULL;
+ }
+ LOG (GNUNET_ERROR_TYPE_INFO, _("Starting `%s' process to generate entropy\n"),
+ "find");
+ genproc =
+ GNUNET_OS_start_process (GNUNET_NO,
+ NULL, NULL, "sh", "sh", "-c",
+ "exec find / -mount -type f -exec cp {} /dev/null \\; 2>/dev/null",
+ NULL);
+}
+
+
+static void
+killfind ()
+{
+ if (genproc != NULL)
+ {
+ GNUNET_OS_process_kill (genproc, SIGKILL);
+ GNUNET_OS_process_close (genproc);
+ genproc = NULL;
+ }
+}
+
+
+void __attribute__ ((constructor)) GNUNET_CRYPTO_random_init ()
+{
+ gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
+ if (!gcry_check_version (GCRYPT_VERSION))
+ {
+ FPRINTF (stderr,
+ _
+ ("libgcrypt has not the expected version (version %s is required).\n"),
+ GCRYPT_VERSION);
+ GNUNET_abort ();
+ }
+#ifdef GCRYCTL_INITIALIZATION_FINISHED
+ gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
+#endif
+#ifdef gcry_fast_random_poll
+ gcry_fast_random_poll ();
+#endif
+ gcry_set_progress_handler (&entropy_generator, NULL);
+ atexit (&killfind);
+ GNUNET_CRYPTO_seed_weak_random (time (NULL) ^
+ GNUNET_CRYPTO_random_u32
+ (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX));
+}
+
+
+void __attribute__ ((destructor)) GNUNET_CRYPTO_random_fini ()
+{
+ gcry_set_progress_handler (NULL, NULL);
+}
+
+
+
+/* end of crypto_random.c */
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-21 20:33:19 +0000