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path: root/pwmanager/libcrypt/cipher/random.c
authorzautrix <zautrix>2004-10-19 20:16:14 (UTC)
committer zautrix <zautrix>2004-10-19 20:16:14 (UTC)
commiteca49bb06a71980ef61d078904573f25890fc7f2 (patch) (side-by-side diff)
treec5338e3b12430248979a9ac2c1c7e6646ea9ecdf /pwmanager/libcrypt/cipher/random.c
parent53cc32b6e7b1f672bf91b2baf2df6c1e8baf3e0a (diff)
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Initial revision
Diffstat (limited to 'pwmanager/libcrypt/cipher/random.c') (more/less context) (ignore whitespace changes)
-rw-r--r--pwmanager/libcrypt/cipher/random.c1134
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));
+
+}