Diffstat (limited to 'pwmanager/libcrypt/cipher/random.c') (more/less context) (show whitespace changes)
| -rw-r--r-- | pwmanager/libcrypt/cipher/random.c | 1134 |
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)); + +} |