#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)
+
/**
+ * 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.
+ *
+ * @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)
+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);
- 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
- gcry_randomize ((unsigned char *) &ret,
- sizeof (uint32_t),
- GCRY_STRONG_RANDOM);
- 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 * ((double) RANDOM () / RAND_MAX);
- 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 * 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++)
- {
- x = GNUNET_CRYPTO_random_u32 (mode, n);
- tmp = ret[x];
- ret[x] = ret[i];
- ret[i] = tmp;
- }
+ 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 u)
+GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max)
{
uint64_t ret;
+ uint64_t ul;
- GNUNET_assert (u > 0);
- if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
+ 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);
- return ret % u;
+ 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 = u * ((double) RANDOM () / RAND_MAX);
- if (ret >= u)
- ret = u - 1;
- return ret;
+ 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;
}
/**
}
+/**
+ * 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 (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);
+ abort ();
+ }
+#ifdef gcry_fast_random_poll
+ gcry_fast_random_poll ();
+#endif
+ gcry_set_progress_handler (&entropy_generator, NULL);
+ atexit (&killfind);
+ SRANDOM (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