/*
This file is part of GNUnet.
- (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors)
+ (C) 2001, 2002, 2003, 2004, 2005, 2006, 2012 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
#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)
+
+
+/**
+ * GNUNET_YES if we are using a 'weak' (low-entropy) PRNG.
+ */
+static int weak_random;
+
+
+
+/* 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)
+#if defined(RAND_MAX)
+#undef RAND_MAX
+#endif
+#define RAND_MAX 0x7fffffff /* Hopefully this is correct */
+
+
+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 ()
+get_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.
*
GNUNET_assert (i > 0);
- if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
- {
- /* see http://lists.gnupg.org/pipermail/gcrypt-devel/2004-May/000613.html */
+ 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 ();
+ 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;
+ ul = UINT32_MAX - (UINT32_MAX % i);
+ do
+ {
+ gcry_randomize ((unsigned char *) &ret, sizeof (uint32_t),
+ GCRY_STRONG_RANDOM);
}
- else
+ while (ret >= ul);
+ return ret % i;
+ case GNUNET_CRYPTO_QUALITY_NONCE:
+ ul = UINT32_MAX - (UINT32_MAX % i);
+ do
{
- ret = i * weak_random ();
- if (ret >= i)
- ret = i - 1;
- return ret;
+ gcry_create_nonce (&ret, sizeof (ret));
}
+ while (ret >= ul);
+ return ret % i;
+ case GNUNET_CRYPTO_QUALITY_WEAK:
+ ret = i * get_weak_random ();
+ if (ret >= i)
+ ret = i - 1;
+ return ret;
+ default:
+ GNUNET_assert (0);
+ }
+ return 0;
}
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;
- }
+ {
+ x = GNUNET_CRYPTO_random_u32 (mode, i + 1);
+ tmp = ret[x];
+ ret[x] = ret[i];
+ ret[i] = tmp;
+ }
return ret;
}
uint64_t ul;
GNUNET_assert (max > 0);
- if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
+ switch (mode)
+ {
+ case GNUNET_CRYPTO_QUALITY_STRONG:
+ ul = UINT64_MAX - (UINT64_MAX % max);
+ do
{
- ul = UINT64_MAX - (UINT64_MAX % max);
- do
- {
- gcry_randomize ((unsigned char *) &ret,
- sizeof (uint64_t), GCRY_STRONG_RANDOM);
- }
- while (ret >= ul);
- return ret % max;
+ gcry_randomize ((unsigned char *) &ret, sizeof (uint64_t),
+ GCRY_STRONG_RANDOM);
}
- else
+ while (ret >= ul);
+ return ret % max;
+ case GNUNET_CRYPTO_QUALITY_NONCE:
+ ul = UINT64_MAX - (UINT64_MAX % max);
+ do
{
- ret = max * weak_random ();
- if (ret >= max)
- ret = max - 1;
- return ret;
+ gcry_create_nonce (&ret, sizeof (ret));
}
+ while (ret >= ul);
+
+ return ret % max;
+ case GNUNET_CRYPTO_QUALITY_WEAK:
+ ret = max * get_weak_random ();
+ if (ret >= max)
+ ret = max - 1;
+ return ret;
+ default:
+ GNUNET_assert (0);
+ }
+ return 0;
}
+
+/**
+ * Check if we are using weak random number generation.
+ *
+ * @return GNUNET_YES if weak number generation is on
+ */
+int
+GNUNET_CRYPTO_random_is_weak ()
+{
+ return weak_random;
+}
+
+
/**
* This function should only be called in testcases
* where strong entropy gathering is not desired
void
GNUNET_CRYPTO_random_disable_entropy_gathering ()
{
+ weak_random = GNUNET_YES;
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;
+
+
/**
- * Initializer
+ * Function called by libgcrypt whenever we are
+ * blocked gathering entropy.
*/
-void __attribute__ ((constructor)) GNUNET_util_random_init ()
+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_destroy (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_destroy (genproc);
+ genproc = NULL;
+ }
+ LOG (GNUNET_ERROR_TYPE_INFO, _("Starting `%s' process to generate entropy\n"),
+ "find");
+ genproc =
+ GNUNET_OS_start_process (GNUNET_NO, 0,
+ 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_destroy (genproc);
+ genproc = NULL;
+ }
+}
+
+
+void __attribute__ ((constructor)) GNUNET_CRYPTO_random_init ()
{
- SRANDOM (time (NULL));
+ gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
+ if (!gcry_check_version (NEED_LIBGCRYPT_VERSION))
+ {
+ FPRINTF (stderr,
+ _
+ ("libgcrypt has not the expected version (version %s is required).\n"),
+ NEED_LIBGCRYPT_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 */
projects / oweals / gnunet.git / blobdiff