X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_random.c;h=121dbef9a544809cf56b9498243e729bec433347;hb=f491ac4fab469421986f77df0bbf79fefc417786;hp=eea047ac6999fbb11665dd2bd187130c4653e878;hpb=75515782d35eb20040d2d0ef678dd64ebee37ae8;p=oweals%2Fgnunet.git

diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c
index eea047ac6..121dbef9a 100644
--- a/src/util/crypto_random.c
+++ b/src/util/crypto_random.c
@@ -27,11 +27,46 @@
 #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
@@ -40,6 +75,17 @@ 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.
@@ -55,27 +101,43 @@ GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i)
   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 * 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 * weak_random ();
+    if (ret >= i)
+      ret = i - 1;
+    return ret;
+  default:
+    GNUNET_assert (0);
+  }
+  return 0;
 }
 
 
@@ -100,12 +162,12 @@ GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n)
   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;
 }
 
@@ -121,21 +183,38 @@ uint64_t
 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)
+  {
+  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 % 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 * weak_random ();
+    if (ret >= max)
+      ret = max - 1;
+    return ret;
+  default:
+    GNUNET_assert (0);
+  }
+  return 0;
 }
 
 /**
@@ -149,12 +228,103 @@ 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;
+
 /**
- * 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_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 ()
 {
-  SRANDOM (time (NULL));
+  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 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 */