#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_crypto_lib.h"
+#include "gnunet_os_lib.h"
#include <gcrypt.h>
+/**
+ * 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);
+}
+
+
/**
* Produce a random value.
*
static unsigned int invokeCount;
#endif
uint32_t ret;
+ uint32_t ul;
GNUNET_assert (i > 0);
- if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
+ 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
- gcry_randomize ((unsigned char *) &ret,
- sizeof (uint32_t), GCRY_STRONG_RANDOM);
+ ul = UINT32_MAX - (UINT32_MAX % i);
+ do
+ {
+ gcry_randomize ((unsigned char *) &ret,
+ sizeof (uint32_t), GCRY_STRONG_RANDOM);
+ }
+ while (ret >= ul);
return ret % i;
- }
- else
- {
- ret = i * ((double) RANDOM () / RAND_MAX);
+ 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;
}
ret = GNUNET_malloc (n * sizeof (unsigned int));
for (i = 0; i < n; i++)
ret[i] = i;
- for (i = 0; i < n; i++)
+ for (i = n - 1; i > 0; i--)
{
- x = GNUNET_CRYPTO_random_u32 (mode, n);
+ x = GNUNET_CRYPTO_random_u32 (mode, i+1);
tmp = ret[x];
ret[x] = ret[i];
ret[i] = tmp;
GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max)
{
uint64_t ret;
+ uint64_t ul;
GNUNET_assert (max > 0);
- if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
+ switch (mode)
{
- gcry_randomize ((unsigned char *) &ret,
- sizeof (uint64_t), GCRY_STRONG_RANDOM);
+ 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;
- }
- else
- {
- ret = max * ((double) RANDOM () / RAND_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;
}
/**
gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
}
+
/**
- * Initializer
+ * Process ID of the "find" process that we use for
+ * entropy gathering.
*/
-void __attribute__ ((constructor)) GNUNET_util_random_init ()
+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))
+ GNUNET_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))
+ GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "kill");
+ GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (genproc));
+ GNUNET_OS_process_close (genproc);
+ genproc = NULL;
+ }
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ _("Starting `%s' process to generate entropy\n"), "find");
+ genproc = GNUNET_OS_start_process (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 ()
{
SRANDOM (time (NULL));
+ 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);
+ abort ();
+ }
+#ifdef gcry_fast_random_poll
+ gcry_fast_random_poll ();
+#endif
+ gcry_set_progress_handler (&entropy_generator, NULL);
+ atexit (&killfind);
}
+
+void __attribute__ ((destructor)) GNUNET_CRYPTO_random_fini ()
+{
+ gcry_set_progress_handler (NULL, NULL);
+}
+
+
+
/* end of crypto_random.c */
+