Imported Upstream version 0.9.2upstream/0.9.2

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 */