Initial revision

1 files changed, 1134 insertions, 0 deletions

diff --git a/pwmanager/libcrypt/cipher/random.c b/pwmanager/libcrypt/cipher/random.c
new file mode 100644
index 0000000..e0d04a4
--- a/dev/null
+++ b/pwmanager/libcrypt/cipher/random.c
@@ -0,0 +1,1134 @@
+/* random.c  -	random number generator
+ * Copyright (C) 1998, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+/****************
+ * This random number generator is modelled after the one described in
+ * Peter Gutmann's paper: "Software Generation of Practically Strong
+ * Random Numbers". See also chapter 6 in his book "Cryptographic
+ * Security Architecture", New York, 2004, ISBN 0-387-95387-6.
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#ifdef	HAVE_GETHRTIME
+#include <sys/times.h>
+#endif
+#ifdef HAVE_GETTIMEOFDAY
+#include <sys/times.h>
+#endif
+#ifdef HAVE_GETRUSAGE
+#include <sys/resource.h>
+#endif
+#ifdef __MINGW32__
+#include <process.h>
+#endif
+#include "g10lib.h"
+#include "rmd.h"
+#include "random.h"
+#include "rand-internal.h"
+#include "cipher.h" /* only used for the rmd160_hash_buffer() prototype */
+#include "ath.h"
+
+#ifndef RAND_MAX   /* for SunOS */
+#define RAND_MAX 32767
+#endif
+
+
+#if SIZEOF_UNSIGNED_LONG == 8
+#define ADD_VALUE 0xa5a5a5a5a5a5a5a5
+#elif SIZEOF_UNSIGNED_LONG == 4
+#define ADD_VALUE 0xa5a5a5a5
+#else
+#error weird size for an unsigned long
+#endif
+
+#define BLOCKLEN  64   /* hash this amount of bytes */
+#define DIGESTLEN 20   /* into a digest of this length (rmd160) */
+/* poolblocks is the number of digests which make up the pool
+ * and poolsize must be a multiple of the digest length
+ * to make the AND operations faster, the size should also be
+ * a multiple of ulong
+ */
+#define POOLBLOCKS 30
+#define POOLSIZE (POOLBLOCKS*DIGESTLEN)
+#if (POOLSIZE % SIZEOF_UNSIGNED_LONG)
+#error Please make sure that poolsize is a multiple of ulong
+#endif
+#define POOLWORDS (POOLSIZE / SIZEOF_UNSIGNED_LONG)
+
+
+static int is_initialized;
+#define MASK_LEVEL(a) do { (a) &= 3; } while(0)
+static char *rndpool;	/* allocated size is POOLSIZE+BLOCKLEN */
+static char *keypool;	/* allocated size is POOLSIZE+BLOCKLEN */
+static size_t pool_readpos;
+static size_t pool_writepos;
+static int pool_filled;
+static int pool_balance;
+static int just_mixed;
+static int did_initial_extra_seeding;
+static char *seed_file_name;
+static int allow_seed_file_update;
+
+static int secure_alloc;
+static int quick_test;
+static int faked_rng;
+
+static ath_mutex_t pool_lock = ATH_MUTEX_INITIALIZER;
+static int pool_is_locked; /* only used for assertion */
+
+static ath_mutex_t nonce_buffer_lock = ATH_MUTEX_INITIALIZER;
+
+static byte *get_random_bytes( size_t nbytes, int level, int secure );
+static void read_pool( byte *buffer, size_t length, int level );
+static void add_randomness( const void *buffer, size_t length, int source );
+static void random_poll(void);
+static void do_fast_random_poll (void);
+static void read_random_source( int requester, size_t length, int level);
+static int gather_faked( void (*add)(const void*, size_t, int), int requester,
+						    size_t length, int level );
+
+static struct {
+    ulong mixrnd;
+    ulong mixkey;
+    ulong slowpolls;
+    ulong fastpolls;
+    ulong getbytes1;
+    ulong ngetbytes1;
+    ulong getbytes2;
+    ulong ngetbytes2;
+    ulong addbytes;
+    ulong naddbytes;
+} rndstats;
+
+static void (*progress_cb) (void *,const char*,int,int, int );
+static void *progress_cb_data;
+
+/* Note, we assume that this function is used before any concurrent
+   access happens. */
+static void
+initialize(void)
+{
+  int err;
+
+  err = ath_mutex_init (&pool_lock);
+  if (err)
+    log_fatal ("failed to create the pool lock: %s\n", strerror (err) );
+
+  err = ath_mutex_init (&nonce_buffer_lock);
+  if (err)
+    log_fatal ("failed to create the nonce buffer lock: %s\n",
+               strerror (err) );
+    
+  /* The data buffer is allocated somewhat larger, so that we can use
+    this extra space (which is allocated in secure memory) as a
+    temporary hash buffer */
+  rndpool = secure_alloc ? gcry_xcalloc_secure(1,POOLSIZE+BLOCKLEN)
+                         : gcry_xcalloc(1,POOLSIZE+BLOCKLEN);
+  keypool = secure_alloc ? gcry_xcalloc_secure(1,POOLSIZE+BLOCKLEN)
+                         : gcry_xcalloc(1,POOLSIZE+BLOCKLEN);
+  is_initialized = 1;
+
+}
+
+
+/* Used to register a progress callback. */
+void
+_gcry_register_random_progress (void (*cb)(void *,const char*,int,int,int),
+                                void *cb_data )
+{
+  progress_cb = cb;
+  progress_cb_data = cb_data;
+}
+
+
+/* This progress function is currently used by the random modules to give hint
+   on how much more entropy is required. */
+void
+_gcry_random_progress (const char *what, int printchar, int current, int total)
+{
+  if (progress_cb)
+    progress_cb (progress_cb_data, what, printchar, current, total);
+}
+
+
+/* Initialize this random subsystem.  This function merely calls the
+   initialize and does not do anything more.  Doing this is not really
+   required but when running in a threaded environment we might get a
+   race condition otherwise. */
+void
+_gcry_random_initialize ()
+{
+  if (!is_initialized)
+    initialize ();
+}
+
+void
+_gcry_random_dump_stats()
+{
+    log_info (
+	    "random usage: poolsize=%d mixed=%lu polls=%lu/%lu added=%lu/%lu\n"
+	    "              outmix=%lu getlvl1=%lu/%lu getlvl2=%lu/%lu\n",
+	POOLSIZE, rndstats.mixrnd, rndstats.slowpolls, rndstats.fastpolls,
+		  rndstats.naddbytes, rndstats.addbytes,
+	rndstats.mixkey, rndstats.ngetbytes1, rndstats.getbytes1,
+		    rndstats.ngetbytes2, rndstats.getbytes2 );
+}
+
+void
+_gcry_secure_random_alloc()
+{
+    secure_alloc = 1;
+}
+
+
+int
+_gcry_quick_random_gen( int onoff )
+{
+  int last;
+
+  /* No need to lock it here because we are only initializing.  A
+     prerequisite of the entire code is that it has already been
+     initialized before any possible concurrent access */
+  read_random_source(0,0,0); /* init */
+  last = quick_test;
+  if( onoff != -1 )
+    quick_test = onoff;
+  return faked_rng? 1 : last;
+}
+
+int
+_gcry_random_is_faked()
+{
+  if( !is_initialized )
+    initialize();
+  return (faked_rng || quick_test);
+}
+
+/*
+ * Return a pointer to a randomized buffer of LEVEL and NBYTES length.
+ * Caller must free the buffer. 
+ */
+static byte *
+get_random_bytes ( size_t nbytes, int level, int secure)
+{
+  byte *buf, *p;
+  int err;
+
+  /* First a hack toavoid the strong random using our regression test suite. */
+  if (quick_test && level > 1)
+    level = 1;
+
+  /* Make sure the requested level is in range. */
+  MASK_LEVEL(level);
+
+  /* Lock the pool. */
+  err = ath_mutex_lock (&pool_lock);
+  if (err)
+    log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
+  pool_is_locked = 1;
+
+  /* Keep some statistics. */
+  if (level >= 2)
+    {
+      rndstats.getbytes2 += nbytes;
+      rndstats.ngetbytes2++;
+    }
+  else
+    {
+      rndstats.getbytes1 += nbytes;
+      rndstats.ngetbytes1++;
+    }
+
+  /* Allocate the return buffer. */
+  buf = secure && secure_alloc ? gcry_xmalloc_secure( nbytes )
+                               : gcry_xmalloc( nbytes );
+
+  /* Fill that buffer with random. */
+  for (p = buf; nbytes > 0; )
+    {
+      size_t n;
+
+      n = nbytes > POOLSIZE? POOLSIZE : nbytes;
+      read_pool( p, n, level );
+      nbytes -= n;
+      p += n;
+    }
+
+  /* Release the pool lock. */
+  pool_is_locked = 0;
+  err = ath_mutex_unlock (&pool_lock);
+  if (err)
+    log_fatal ("failed to release the pool lock: %s\n", strerror (err));
+
+  /* Return the buffer. */
+  return buf;
+}
+
+
+/* Add BUFLEN bytes from BUF to the internal random pool.  QUALITY
+   should be in the range of 0..100 to indicate the goodness of the
+   entropy added, or -1 for goodness not known. 
+
+   Note, that this function currently does nothing.
+*/
+gcry_error_t
+gcry_random_add_bytes (const void * buf, size_t buflen, int quality)
+{
+  gcry_err_code_t err = GPG_ERR_NO_ERROR;
+
+  if (!buf || quality < -1 || quality > 100)
+    err = GPG_ERR_INV_ARG;
+  if (!buflen)
+    return 0; /* Shortcut this dummy case. */
+#if 0
+  /* Before we actuall enable this code, we need to lock the pool,
+     have a look at the quality and find a way to add them without
+     disturbing the real entropy (we have estimated). */
+  /*add_randomness( buf, buflen, 1 );*/
+#endif
+  return err;
+}   
+    
+/* The public function to return random data of the quality LEVEL. */
+void *
+gcry_random_bytes( size_t nbytes, enum gcry_random_level level )
+{
+  if (!is_initialized)
+    initialize();
+  return get_random_bytes( nbytes, level, 0 );
+}
+
+/* The public function to return random data of the quality LEVEL;
+   this version of the function retrun the random a buffer allocated
+   in secure memory. */
+void *
+gcry_random_bytes_secure( size_t nbytes, enum gcry_random_level level )
+{
+  if (!is_initialized)
+    initialize();
+  return get_random_bytes( nbytes, level, 1 );
+}
+
+
+/* Public function to fill the buffer with LENGTH bytes of
+   cryptographically strong random bytes. level 0 is not very strong,
+   1 is strong enough for most usage, 2 is good for key generation
+   stuff but may be very slow.  */
+void
+gcry_randomize (byte *buffer, size_t length, enum gcry_random_level level)
+{
+  byte *p;
+  int err;
+
+  /* Make sure we are initialized. */
+  if (!is_initialized)
+    initialize ();
+
+  /* Handle our hack used for regression tests of Libgcrypt. */
+  if( quick_test && level > 1 )
+    level = 1;
+
+  /* Make sure the level is okay. */
+  MASK_LEVEL(level);
+
+  /* Acquire the pool lock. */
+  err = ath_mutex_lock (&pool_lock);
+  if (err)
+    log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
+  pool_is_locked = 1;
+
+  /* Update the statistics. */
+  if (level >= 2)
+    {
+      rndstats.getbytes2 += length;
+      rndstats.ngetbytes2++;
+    }
+  else
+    {
+      rndstats.getbytes1 += length;
+      rndstats.ngetbytes1++;
+    }
+
+  /* Read the random into the provided buffer. */
+  for (p = buffer; length > 0;)
+    {
+      size_t n;
+
+      n = length > POOLSIZE? POOLSIZE : length;
+      read_pool (p, n, level);
+      length -= n;
+      p += n;
+    }
+
+  /* Release the pool lock. */
+  pool_is_locked = 0;
+  err = ath_mutex_unlock (&pool_lock);
+  if (err)
+    log_fatal ("failed to release the pool lock: %s\n", strerror (err));
+
+}
+
+
+
+
+/*
+   Mix the pool:
+
+   |........blocks*20byte........|20byte|..44byte..|
+   <..44byte..>           <20byte> 
+        |                    |
+        |                    +------+
+        +---------------------------|----------+
+                                    v          v
+   |........blocks*20byte........|20byte|..44byte..|
+                                 <.....64bytes.....>   
+                                         |
+      +----------------------------------+
+     Hash
+      v
+   |.............................|20byte|..44byte..|
+   <20byte><20byte><..44byte..>
+      |                |
+      |                +---------------------+
+      +-----------------------------+        |
+                                    v        v
+   |.............................|20byte|..44byte..|
+                                 <.....64byte......>
+                                        |
+              +-------------------------+
+             Hash
+              v
+   |.............................|20byte|..44byte..|
+   <20byte><20byte><..44byte..>
+
+   and so on until we did this for all blocks. 
+
+   To better protect against implementation errors in this code, we
+   xor a digest of the entire pool into the pool before mixing.
+
+   Note, that this function muts only be called with a locked pool.
+ */
+static void
+mix_pool(byte *pool)
+{
+  static unsigned char failsafe_digest[DIGESTLEN];
+  static int failsafe_digest_valid;
+
+  char *hashbuf = pool + POOLSIZE;
+  char *p, *pend;
+  int i, n;
+  RMD160_CONTEXT md;
+
+#if DIGESTLEN != 20
+#error must have a digest length of 20 for ripe-md-160
+#endif
+
+  assert (pool_is_locked);
+  _gcry_rmd160_init( &md );
+
+  /* loop over the pool */
+  pend = pool + POOLSIZE;
+  memcpy(hashbuf, pend - DIGESTLEN, DIGESTLEN );
+  memcpy(hashbuf+DIGESTLEN, pool, BLOCKLEN-DIGESTLEN);
+  _gcry_rmd160_mixblock( &md, hashbuf);
+  memcpy(pool, hashbuf, 20 );
+
+  if (failsafe_digest_valid && (char *)pool == rndpool)
+    {
+      for (i=0; i < 20; i++)
+        pool[i] ^= failsafe_digest[i];
+    }
+  
+  p = pool;
+  for (n=1; n < POOLBLOCKS; n++)
+    {
+      memcpy (hashbuf, p, DIGESTLEN);
+
+      p += DIGESTLEN;
+      if (p+DIGESTLEN+BLOCKLEN < pend)
+        memcpy (hashbuf+DIGESTLEN, p+DIGESTLEN, BLOCKLEN-DIGESTLEN);
+      else 
+        {
+          char *pp = p + DIGESTLEN;
+          
+          for (i=DIGESTLEN; i < BLOCKLEN; i++ )
+            {
+              if ( pp >= pend )
+                pp = pool;
+              hashbuf[i] = *pp++;
+	    }
+	}
+      
+      _gcry_rmd160_mixblock( &md, hashbuf);
+      memcpy(p, hashbuf, 20 );
+    }
+
+    /* Our hash implementation does only leave small parts (64 bytes)
+       of the pool on the stack, so it is okay not to require secure
+       memory here.  Before we use this pool, it will be copied to the
+       help buffer anyway. */
+    if ( (char*)pool == rndpool)
+      {
+        _gcry_rmd160_hash_buffer (failsafe_digest, pool, POOLSIZE);
+        failsafe_digest_valid = 1;
+      }
+
+    _gcry_burn_stack (384); /* for the rmd160_mixblock(), rmd160_hash_buffer */
+}
+
+
+void
+_gcry_set_random_seed_file( const char *name )
+{
+  if (seed_file_name)
+    BUG ();
+  seed_file_name = gcry_xstrdup (name);
+}
+
+
+/*
+  Read in a seed form the random_seed file
+  and return true if this was successful.
+ */
+static int
+read_seed_file (void)
+{
+  int fd;
+  struct stat sb;
+  unsigned char buffer[POOLSIZE];
+  int n;
+
+  assert (pool_is_locked);
+
+  if (!seed_file_name)
+    return 0;
+  
+#ifdef HAVE_DOSISH_SYSTEM
+  fd = open( seed_file_name, O_RDONLY | O_BINARY );
+#else
+  fd = open( seed_file_name, O_RDONLY );
+#endif
+  if( fd == -1 && errno == ENOENT)
+    {
+      allow_seed_file_update = 1;
+      return 0;
+    }
+
+  if (fd == -1 )
+    {
+      log_info(_("can't open `%s': %s\n"), seed_file_name, strerror(errno) );
+      return 0;
+    }
+  if (fstat( fd, &sb ) )
+    {
+      log_info(_("can't stat `%s': %s\n"), seed_file_name, strerror(errno) );
+      close(fd);
+      return 0;
+    }
+  if (!S_ISREG(sb.st_mode) )
+    {
+      log_info(_("`%s' is not a regular file - ignored\n"), seed_file_name );
+      close(fd);
+      return 0;
+    }
+  if (!sb.st_size )
+    {
+      log_info(_("note: random_seed file is empty\n") );
+      close(fd);
+      allow_seed_file_update = 1;
+      return 0;
+    }
+  if (sb.st_size != POOLSIZE ) 
+    {
+      log_info(_("warning: invalid size of random_seed file - not used\n") );
+      close(fd);
+      return 0;
+    }
+
+  do
+    {
+      n = read( fd, buffer, POOLSIZE );
+    } 
+  while (n == -1 && errno == EINTR );
+
+  if (n != POOLSIZE)
+    {
+      log_fatal(_("can't read `%s': %s\n"), seed_file_name,strerror(errno) );
+      close(fd);/*NOTREACHED*/
+      return 0;
+    }
+  
+  close(fd);
+
+  add_randomness( buffer, POOLSIZE, 0 );
+  /* add some minor entropy to the pool now (this will also force a mixing) */
+  {	
+    pid_t x = getpid();
+    add_randomness( &x, sizeof(x), 0 );
+  }
+  {
+    time_t x = time(NULL);
+    add_randomness( &x, sizeof(x), 0 );
+  }
+  {	
+    clock_t x = clock();
+    add_randomness( &x, sizeof(x), 0 );
+  }
+
+  /* And read a few bytes from our entropy source.  By using a level
+   * of 0 this will not block and might not return anything with some
+   * entropy drivers, however the rndlinux driver will use
+   * /dev/urandom and return some stuff - Do not read to much as we
+   * want to be friendly to the scare system entropy resource. */
+  read_random_source( 0, 16, 0 );
+
+  allow_seed_file_update = 1;
+  return 1;
+}
+
+
+void
+_gcry_update_random_seed_file()
+{
+  ulong *sp, *dp;
+  int fd, i;
+  int err;
+  
+  if ( !seed_file_name || !is_initialized || !pool_filled )
+    return;
+  if ( !allow_seed_file_update )
+    {
+      log_info(_("note: random_seed file not updated\n"));
+      return;
+    }
+
+  err = ath_mutex_lock (&pool_lock);
+  if (err)
+    log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
+  pool_is_locked = 1;
+
+  /* copy the entropy pool to a scratch pool and mix both of them */
+  for (i=0,dp=(ulong*)keypool, sp=(ulong*)rndpool;
+       i < POOLWORDS; i++, dp++, sp++ ) 
+    {
+      *dp = *sp + ADD_VALUE;
+    }
+  mix_pool(rndpool); rndstats.mixrnd++;
+  mix_pool(keypool); rndstats.mixkey++;
+
+#ifdef HAVE_DOSISH_SYSTEM
+  fd = open (seed_file_name, O_WRONLY|O_CREAT|O_TRUNC|O_BINARY,
+             S_IRUSR|S_IWUSR );
+#else
+  fd = open (seed_file_name, O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR );
+#endif
+
+  if (fd == -1 )
+    log_info (_("can't create `%s': %s\n"), seed_file_name, strerror(errno) );
+  else 
+    {
+      do
+        {
+          i = write (fd, keypool, POOLSIZE );
+        } 
+      while( i == -1 && errno == EINTR );
+      if (i != POOLSIZE) 
+        log_info (_("can't write `%s': %s\n"),
+                  seed_file_name, strerror(errno) );
+      if (close(fd))
+        log_info(_("can't close `%s': %s\n"),
+                 seed_file_name, strerror(errno) );
+    }
+  
+  pool_is_locked = 0;
+  err = ath_mutex_unlock (&pool_lock);
+  if (err)
+    log_fatal ("failed to release the pool lock: %s\n", strerror (err));
+
+}
+
+
+/* Read random out of the pool. This function is the core of the
+   public random fucntions.  Note that Level 0 is not anymore handeld
+   special and in fact an alias for level 1. */
+static void
+read_pool (byte *buffer, size_t length, int level)
+{
+  int i;
+  unsigned long *sp, *dp;
+  volatile pid_t my_pid; /* The volatile is there to make sure the
+                            compiler does not optimize the code away
+                            in case the getpid function is badly
+                            attributed. */
+
+ retry:
+  /* Get our own pid, so that we can detect a fork. */
+  my_pid = getpid ();
+
+  assert (pool_is_locked);
+
+  /* Our code does not allow to extract more than POOLSIZE.  Better
+     check it here. */
+  if (length > POOLSIZE)
+    {
+      log_bug("too many random bits requested\n");
+    }
+
+  if (!pool_filled)
+    {
+      if (read_seed_file() )
+        pool_filled = 1;
+    }
+
+  /* For level 2 quality (key generation) we always make sure that the
+     pool has been seeded enough initially. */
+  if (level == 2 && !did_initial_extra_seeding)
+    {
+      size_t needed;
+
+      pool_balance = 0;
+      needed = length - pool_balance;
+      if (needed < POOLSIZE/2)
+        needed = POOLSIZE/2;
+      else if( needed > POOLSIZE )
+        BUG ();
+      read_random_source (3, needed, 2);
+      pool_balance += needed;
+      did_initial_extra_seeding = 1;
+    }
+
+  /* For level 2 make sure that there is enough random in the pool. */
+  if (level == 2 && pool_balance < length)
+    {
+      size_t needed;
+      
+      if (pool_balance < 0)
+        pool_balance = 0;
+      needed = length - pool_balance;
+      if (needed > POOLSIZE)
+        BUG ();
+      read_random_source( 3, needed, 2 );
+      pool_balance += needed;
+    }
+
+  /* make sure the pool is filled */
+  while (!pool_filled)
+    random_poll();
+
+  /* Always do a fast random poll (we have to use the unlocked version). */
+  do_fast_random_poll();
+
+  /* Mix the pool (if add_randomness() didn't it). */
+  if (!just_mixed)
+    {
+      mix_pool(rndpool);
+      rndstats.mixrnd++;
+    }
+
+  /* Create a new pool. */
+  for(i=0,dp=(ulong*)keypool, sp=(ulong*)rndpool;
+      i < POOLWORDS; i++, dp++, sp++ )
+    *dp = *sp + ADD_VALUE;
+
+  /* Mix both pools. */
+  mix_pool(rndpool); rndstats.mixrnd++;
+  mix_pool(keypool); rndstats.mixkey++;
+
+  /* Read the required data.  We use a readpoiter to read from a
+     different position each time */
+  while (length--)
+    {
+      *buffer++ = keypool[pool_readpos++];
+      if (pool_readpos >= POOLSIZE)
+        pool_readpos = 0;
+      pool_balance--;
+    }
+ 
+  if (pool_balance < 0)
+    pool_balance = 0;
+
+  /* Clear the keypool. */
+  memset (keypool, 0, POOLSIZE);
+
+  /* We need to detect whether a fork has happened.  A fork might have
+     an identical pool and thus the child and the parent could emit
+     the very same random number.  Obviously this can only happen when
+     running multi-threaded and the pool lock should even catch this.
+     However things do get wrong and thus we better check and retry it
+     here.  We assume that the thread library has no other fatal
+     faults, though.
+   */
+  if ( getpid () != my_pid )
+    goto retry;
+}
+
+
+/*
+ * Add LENGTH bytes of randomness from buffer to the pool.
+ * source may be used to specify the randomness source.
+ * Source is:
+ *	0 - used ony for initialization
+ *	1 - fast random poll function
+ *	2 - normal poll function
+ *	3 - used when level 2 random quality has been requested
+ *	    to do an extra pool seed.
+ */
+static void
+add_randomness( const void *buffer, size_t length, int source )
+{
+  const byte *p = buffer;
+
+  assert (pool_is_locked);
+  if (!is_initialized)
+    initialize ();
+  rndstats.addbytes += length;
+  rndstats.naddbytes++;
+  while (length-- )
+    {
+      rndpool[pool_writepos++] ^= *p++;
+      if (pool_writepos >= POOLSIZE )
+        {
+          if (source > 1)
+            pool_filled = 1;
+          pool_writepos = 0;
+          mix_pool(rndpool); rndstats.mixrnd++;
+          just_mixed = !length;
+	}
+    }
+}
+
+
+
+static void
+random_poll()
+{
+  rndstats.slowpolls++;
+  read_random_source (2, POOLSIZE/5, 1);
+}
+
+
+static int (*
+getfnc_gather_random (void))(void (*)(const void*, size_t, int), int,
+			     size_t, int)
+{
+  static int (*fnc)(void (*)(const void*, size_t, int), int, size_t, int);
+  
+  if (fnc)
+    return fnc;
+
+#if USE_RNDLINUX
+  if ( !access (NAME_OF_DEV_RANDOM, R_OK)
+       && !access (NAME_OF_DEV_URANDOM, R_OK))
+    {
+      fnc = _gcry_rndlinux_gather_random;
+      return fnc;
+    }
+#endif
+
+#if USE_RNDEGD
+  if ( _gcry_rndegd_connect_socket (1) != -1 )
+    {
+      fnc = _gcry_rndegd_gather_random;
+      return fnc;
+    }
+#endif
+
+#if USE_RNDUNIX
+  fnc = _gcry_rndunix_gather_random;
+  return fnc;
+#endif
+
+#if USE_RNDW32
+  fnc = _gcry_rndw32_gather_random;
+  return fnc;
+#endif
+
+  log_fatal (_("no entropy gathering module detected\n"));
+
+  return NULL; /*NOTREACHED*/
+}
+
+static void (*
+getfnc_fast_random_poll (void))( void (*)(const void*, size_t, int), int)
+{
+#if USE_RNDW32
+  return _gcry_rndw32_gather_random_fast;
+#endif
+  return NULL;
+}
+
+
+static void
+do_fast_random_poll (void)
+{
+  static void (*fnc)( void (*)(const void*, size_t, int), int) = NULL;
+  static int initialized = 0;
+
+  assert (pool_is_locked);
+
+  rndstats.fastpolls++;
+
+  if (!initialized )
+    {
+      if (!is_initialized )
+        initialize();
+      initialized = 1;
+      fnc = getfnc_fast_random_poll ();
+    }
+
+  if (fnc)
+    (*fnc)( add_randomness, 1 );
+
+  /* Continue with the generic functions. */
+#if HAVE_GETHRTIME
+  {	
+    hrtime_t tv;
+    tv = gethrtime();
+    add_randomness( &tv, sizeof(tv), 1 );
+  }
+#elif HAVE_GETTIMEOFDAY
+  {	
+    struct timeval tv;
+    if( gettimeofday( &tv, NULL ) )
+      BUG();
+    add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
+    add_randomness( &tv.tv_usec, sizeof(tv.tv_usec), 1 );
+  }
+#elif HAVE_CLOCK_GETTIME
+  {	struct timespec tv;
+  if( clock_gettime( CLOCK_REALTIME, &tv ) == -1 )
+    BUG();
+  add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
+  add_randomness( &tv.tv_nsec, sizeof(tv.tv_nsec), 1 );
+  }
+#else /* use times */
+# ifndef HAVE_DOSISH_SYSTEM
+  {	struct tms buf;
+  times( &buf );
+  add_randomness( &buf, sizeof buf, 1 );
+  }
+# endif
+#endif
+
+#ifdef HAVE_GETRUSAGE
+# ifdef RUSAGE_SELF
+  {	
+    struct rusage buf;
+    /* QNX/Neutrino does return ENOSYS - so we just ignore it and
+     * add whatever is in buf.  In a chroot environment it might not
+     * work at all (i.e. because /proc/ is not accessible), so we better 
+     * ugnore all error codes and hope for the best
+     */
+    getrusage (RUSAGE_SELF, &buf );
+    add_randomness( &buf, sizeof buf, 1 );
+    memset( &buf, 0, sizeof buf );
+  }
+# else /*!RUSAGE_SELF*/
+#  ifdef __GCC__
+#   warning There is no RUSAGE_SELF on this system
+#  endif
+# endif /*!RUSAGE_SELF*/
+#endif /*HAVE_GETRUSAGE*/
+
+  /* time and clock are availabe on all systems - so we better do it
+     just in case one of the above functions didn't work */
+  {
+    time_t x = time(NULL);
+    add_randomness( &x, sizeof(x), 1 );
+  }
+  {	
+    clock_t x = clock();
+    add_randomness( &x, sizeof(x), 1 );
+  }
+}
+
+
+/* The fast random pool function as called at some places in
+   libgcrypt.  This is merely a wrapper to make sure that this module
+   is initalized and to look the pool. */
+void
+_gcry_fast_random_poll (void)
+{
+  int err;
+
+  /* We have to make sure that the intialization is done because this
+     gatherer might be called before any other functions and it is not
+     sufficient to initialize it within do_fast_random_pool because we
+     want to use the mutex here. FIXME: Whe should initialize the
+     mutex using a global constructor independent from the
+     initialization of the pool. */
+  if (!is_initialized)
+    initialize ();
+  err = ath_mutex_lock (&pool_lock);
+  if (err)
+    log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
+  pool_is_locked = 1;
+
+  do_fast_random_poll ();
+
+  pool_is_locked = 0;
+  err = ath_mutex_unlock (&pool_lock);
+  if (err)
+    log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
+
+}
+
+
+
+static void
+read_random_source( int requester, size_t length, int level )
+{
+  static int (*fnc)(void (*)(const void*, size_t, int), int,
+                             size_t, int) = NULL;
+  if (!fnc ) 
+    {
+      if (!is_initialized )
+        initialize();
+
+      fnc = getfnc_gather_random ();
+
+      if (!fnc)
+        {
+          faked_rng = 1;
+          fnc = gather_faked;
+	}
+      if (!requester && !length && !level)
+        return; /* Just the init was requested. */
+    }
+
+  if ((*fnc)( add_randomness, requester, length, level ) < 0)
+    log_fatal ("No way to gather entropy for the RNG\n");
+}
+
+
+static int
+gather_faked( void (*add)(const void*, size_t, int), int requester,
+	      size_t length, int level )
+{
+    static int initialized=0;
+    size_t n;
+    char *buffer, *p;
+
+    if( !initialized ) {
+	log_info(_("WARNING: using insecure random number generator!!\n"));
+	/* we can't use tty_printf here - do we need this function at
+	  all - does it really make sense or canit be viewed as a potential
+	  security problem ? wk 17.11.99 */
+#if 0
+	tty_printf(_("The random number generator is only a kludge to let\n"
+		   "it run - it is in no way a strong RNG!\n\n"
+		   "DON'T USE ANY DATA GENERATED BY THIS PROGRAM!!\n\n"));
+#endif
+	initialized=1;
+#ifdef HAVE_RAND
+	srand( time(NULL)*getpid());
+#else
+	srandom( time(NULL)*getpid());
+#endif
+    }
+
+    p = buffer = gcry_xmalloc( length );
+    n = length;
+#ifdef HAVE_RAND
+    while( n-- )
+	*p++ = ((unsigned)(1 + (int) (256.0*rand()/(RAND_MAX+1.0)))-1);
+#else
+    while( n-- )
+	*p++ = ((unsigned)(1 + (int) (256.0*random()/(RAND_MAX+1.0)))-1);
+#endif
+    add_randomness( buffer, length, requester );
+    gcry_free(buffer);
+    return 0; /* okay */
+}
+
+
+/* Create an unpredicable nonce of LENGTH bytes in BUFFER. */
+void
+gcry_create_nonce (unsigned char *buffer, size_t length)
+{
+  static unsigned char nonce_buffer[20+8];
+  static int nonce_buffer_initialized = 0;
+  unsigned char *p;
+  size_t n;
+  int err;
+
+  /* Make sure we are initialized. */
+  if (!is_initialized)
+    initialize ();
+
+  /* Acquire the nonce buffer lock. */
+  err = ath_mutex_lock (&nonce_buffer_lock);
+  if (err)
+    log_fatal ("failed to acquire the nonce buffer lock: %s\n",
+               strerror (err));
+
+  /* The first time intialize our buffer. */
+  if (!nonce_buffer_initialized)
+    {
+      pid_t apid = getpid ();
+      time_t atime = time (NULL);
+
+      if ((sizeof apid + sizeof atime) > sizeof nonce_buffer)
+        BUG ();
+
+      /* Initialize the first 20 bytes with a reasonable value so that
+         a failure of gcry_randomize won't affect us too much.  Don't
+         care about the uninitialized remaining bytes. */
+      p = nonce_buffer;
+      memcpy (p, &apid, sizeof apid);
+      p += sizeof apid;
+      memcpy (p, &atime, sizeof atime); 
+
+      /* Initialize the never changing private part of 64 bits. */
+      gcry_randomize (nonce_buffer+20, 8, GCRY_WEAK_RANDOM);
+
+      nonce_buffer_initialized = 1;
+    }
+
+  /* Create the nonce by hashing the entire buffer, returning the hash
+     and updating the first 20 bytes of the buffer with this hash. */
+  for (p = buffer; length > 0; length -= n, p += n)
+    {
+      _gcry_sha1_hash_buffer (nonce_buffer,
+                              nonce_buffer, sizeof nonce_buffer);
+      n = length > 20? 20 : length;
+      memcpy (p, nonce_buffer, n);
+    }
+
+
+  /* Release the nonce buffer lock. */
+  err = ath_mutex_unlock (&nonce_buffer_lock);
+  if (err)
+    log_fatal ("failed to release the nonce buffer lock: %s\n",
+               strerror (err));
+
+}