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Diffstat (limited to 'libotr/libgcrypt-1.8.7/random/random-csprng.c')
| -rw-r--r-- | libotr/libgcrypt-1.8.7/random/random-csprng.c | 1363 |
1 files changed, 1363 insertions, 0 deletions
diff --git a/libotr/libgcrypt-1.8.7/random/random-csprng.c b/libotr/libgcrypt-1.8.7/random/random-csprng.c new file mode 100644 index 0000000..6073ee3 --- /dev/null +++ b/libotr/libgcrypt-1.8.7/random/random-csprng.c @@ -0,0 +1,1363 @@ +/* random-csprng.c - CSPRNG style random number generator (libgcrypt classic) + * Copyright (C) 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006, + * 2007, 2008, 2010, 2012 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, see <http://www.gnu.org/licenses/>. + */ + +/* + This random number generator is modelled after the one described in + Peter Gutmann's 1998 Usenix Security Symposium 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. + + Note that the acronym CSPRNG stands for "Continuously Seeded + PseudoRandom Number Generator" as used in Peter's implementation of + the paper and not only for "Cryptographically Secure PseudoRandom + Number Generator". + */ + + +#include <config.h> +#include <stdio.h> +#include <stdlib.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/time.h> +#endif +#ifdef HAVE_GETRUSAGE +#include <sys/resource.h> +#endif +#ifdef __MINGW32__ +#include <process.h> +#endif +#include "g10lib.h" +#include "random.h" +#include "rand-internal.h" +#include "cipher.h" /* _gcry_sha1_hash_buffer */ +#include "../cipher/sha1.h" /* _gcry_sha1_mixblock */ + +#ifndef RAND_MAX /* For SunOS. */ +#define RAND_MAX 32767 +#endif + +/* Check whether we can lock the seed file read write. */ +#if defined(HAVE_FCNTL) && defined(HAVE_FTRUNCATE) && !defined(HAVE_W32_SYSTEM) +#define LOCK_SEED_FILE 1 +#else +#define LOCK_SEED_FILE 0 +#endif + +/* Define the constant we use for transforming the pool at read-out. */ +#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 + +/* Contstants pertaining to the hash pool. */ +#define BLOCKLEN 64 /* Hash this amount of bytes... */ +#define DIGESTLEN 20 /* ... into a digest of this length (sha-1). */ +/* POOLBLOCKS is the number of digests which make up the pool. */ +#define POOLBLOCKS 30 +/* POOLSIZE must be a multiple of the digest length to make the AND + operations faster, the size should also be a multiple of unsigned + long. */ +#define POOLSIZE (POOLBLOCKS*DIGESTLEN) +#if (POOLSIZE % SIZEOF_UNSIGNED_LONG) +#error Please make sure that poolsize is a multiple of unsigned long +#endif +#define POOLWORDS (POOLSIZE / SIZEOF_UNSIGNED_LONG) + + +/* RNDPOOL is the pool we use to collect the entropy and to stir it + up. Its allocated size is POOLSIZE+BLOCKLEN. Note that this is + also an indication on whether the module has been fully + initialized. */ +static unsigned char *rndpool; + +/* KEYPOOL is used as a scratch copy to read out random from RNDPOOL. + Its allocated size is also POOLSIZE+BLOCKLEN. */ +static unsigned char *keypool; + +/* This is the offset into RNDPOOL where the next random bytes are to + be mixed in. */ +static size_t pool_writepos; + +/* When reading data out of KEYPOOL, we start the read at different + positions. This variable keeps track on where to read next. */ +static size_t pool_readpos; + +/* This flag is set to true as soon as the pool has been completely + filled the first time. This may happen either by reading a seed + file or by adding enough entropy. */ +static int pool_filled; + +/* This counter is used to track whether the initial seeding has been + done with enough bytes from a reliable entropy source. */ +static size_t pool_filled_counter; + +/* If random of level GCRY_VERY_STRONG_RANDOM has been requested we + have stricter requirements on what kind of entropy is in the pool. + In particular POOL_FILLED is not sufficient. Thus we add some + extra seeding and set this flag to true if the extra seeding has + been done. */ +static int did_initial_extra_seeding; + +/* This variable is used to estimated the amount of fresh entropy + available in RNDPOOL. */ +static int pool_balance; + +/* After a mixing operation this variable will be set to true and + cleared if new entropy has been added or a remix is required for + other reasons. */ +static int just_mixed; + +/* The name of the seed file or NULL if no seed file has been defined. + The seed file needs to be registered at initialiation time. We + keep a malloced copy here. */ +static char *seed_file_name; + +/* If a seed file has been registered and maybe updated on exit this + flag set. */ +static int allow_seed_file_update; + +/* Option flag set at initialiation time to force allocation of the + pool in secure memory. */ +static int secure_alloc; + +/* This function pointer is set to the actual entropy gathering + function during initialization. After initialization it is + guaranteed to point to function. (On systems without a random + gatherer module a dummy function is used).*/ +static int (*slow_gather_fnc)(void (*)(const void*, size_t, + enum random_origins), + enum random_origins, size_t, int); + +/* This function is set to the actual fast entropy gathering function + during initialization. If it is NULL, no such function is + available. */ +static void (*fast_gather_fnc)(void (*)(const void*, size_t, + enum random_origins), + enum random_origins); + + +/* Option flag useful for debugging and the test suite. If set + requests for very strong random are degraded to strong random. Not + used by regular applications. */ +static int quick_test; + +/* This is the lock we use to protect all pool operations. */ +GPGRT_LOCK_DEFINE (pool_lock); + +/* This is a helper for assert calls. These calls are used to assert + that functions are called in a locked state. It is not meant to be + thread-safe but as a method to get aware of missing locks in the + test suite. */ +static int pool_is_locked; + + +/* We keep some counters in this structure for the sake of the + _gcry_random_dump_stats () function. */ +static struct +{ + unsigned long mixrnd; + unsigned long mixkey; + unsigned long slowpolls; + unsigned long fastpolls; + unsigned long getbytes1; + unsigned long ngetbytes1; + unsigned long getbytes2; + unsigned long ngetbytes2; + unsigned long addbytes; + unsigned long naddbytes; +} rndstats; + + + +/* --- Stuff pertaining to the random daemon support. --- */ +#ifdef USE_RANDOM_DAEMON + +/* If ALLOW_DAEMON is true, the module will try to use the random + daemon first. If the daemon has failed, this variable is set to + back to false and the code continues as normal. Note, we don't + test this flag in a locked state because a wrong value does not + harm and the trhead will find out itself that the daemon does not + work and set it (again) to false. */ +static int allow_daemon; + +/* During initialization, the user may set a non-default socket name + for accessing the random daemon. If this value is NULL, the + default name will be used. */ +static char *daemon_socket_name; + +#endif /*USE_RANDOM_DAEMON*/ + + + +/* --- Prototypes --- */ +static void read_pool (byte *buffer, size_t length, int level ); +static void add_randomness (const void *buffer, size_t length, + enum random_origins origin); +static void random_poll (void); +static void do_fast_random_poll (void); +static int (*getfnc_gather_random (void))(void (*)(const void*, size_t, + enum random_origins), + enum random_origins, size_t, int); +static void (*getfnc_fast_random_poll (void))(void (*)(const void*, size_t, + enum random_origins), + enum random_origins); +static void read_random_source (enum random_origins origin, + size_t length, int level); + + + +/* --- Functions --- */ + + +/* Basic initialization which is required to initialize mutexes and + such. It does not run a full initialization so that the filling of + the random pool can be delayed until it is actually needed. We + assume that this function is used before any concurrent access + happens. */ +static void +initialize_basics(void) +{ + static int initialized; + + if (!initialized) + { + initialized = 1; + +#ifdef USE_RANDOM_DAEMON + _gcry_daemon_initialize_basics (); +#endif /*USE_RANDOM_DAEMON*/ + + /* Make sure that we are still using the values we have + traditionally used for the random levels. */ + gcry_assert (GCRY_WEAK_RANDOM == 0 + && GCRY_STRONG_RANDOM == 1 + && GCRY_VERY_STRONG_RANDOM == 2); + } +} + +/* Take the pool lock. */ +static void +lock_pool (void) +{ + int err; + + err = gpgrt_lock_lock (&pool_lock); + if (err) + log_fatal ("failed to acquire the pool lock: %s\n", gpg_strerror (err)); + pool_is_locked = 1; +} + +/* Release the pool lock. */ +static void +unlock_pool (void) +{ + int err; + + pool_is_locked = 0; + err = gpgrt_lock_unlock (&pool_lock); + if (err) + log_fatal ("failed to release the pool lock: %s\n", gpg_strerror (err)); +} + + +/* Full initialization of this module. */ +static void +initialize(void) +{ + /* Although the basic initialization should have happened already, + we call it here to make sure that all prerequisites are met. */ + initialize_basics (); + + /* Now we can look the pool and complete the initialization if + necessary. */ + lock_pool (); + if (!rndpool) + { + /* 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 + ? xcalloc_secure (1, POOLSIZE + BLOCKLEN) + : xcalloc (1, POOLSIZE + BLOCKLEN)); + keypool = (secure_alloc + ? xcalloc_secure (1, POOLSIZE + BLOCKLEN) + : xcalloc (1, POOLSIZE + BLOCKLEN)); + + /* Setup the slow entropy gathering function. The code requires + that this function exists. */ + slow_gather_fnc = getfnc_gather_random (); + + /* Setup the fast entropy gathering function. */ + fast_gather_fnc = getfnc_fast_random_poll (); + + } + unlock_pool (); +} + + + + +/* Initialize this random subsystem. If FULL is false, 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_rngcsprng_initialize (int full) +{ + if (!full) + initialize_basics (); + else + initialize (); +} + + +/* Try to close the FDs of the random gather module. This is + currently only implemented for rndlinux. */ +void +_gcry_rngcsprng_close_fds (void) +{ + lock_pool (); +#if USE_RNDLINUX + _gcry_rndlinux_gather_random (NULL, 0, 0, 0); + pool_filled = 0; /* Force re-open on next use. */ +#endif + unlock_pool (); +} + + +void +_gcry_rngcsprng_dump_stats (void) +{ + /* In theory we would need to lock the stats here. However this + function is usually called during cleanup and then we _might_ run + into problems. */ + + log_info ("random usage: poolsize=%d mixed=%lu polls=%lu/%lu added=%lu/%lu\n" + " outmix=%lu getlvl1=%lu/%lu getlvl2=%lu/%lu%s\n", + POOLSIZE, rndstats.mixrnd, rndstats.slowpolls, rndstats.fastpolls, + rndstats.naddbytes, rndstats.addbytes, + rndstats.mixkey, rndstats.ngetbytes1, rndstats.getbytes1, + rndstats.ngetbytes2, rndstats.getbytes2, + _gcry_rndhw_failed_p()? " (hwrng failed)":""); +} + + +/* This function should be called during initialization and before + initialization of this module to place the random pools into secure + memory. */ +void +_gcry_rngcsprng_secure_alloc (void) +{ + secure_alloc = 1; +} + + +/* This may be called before full initialization to degrade the + quality of the RNG for the sake of a faster running test suite. */ +void +_gcry_rngcsprng_enable_quick_gen (void) +{ + quick_test = 1; +} + + +void +_gcry_rngcsprng_set_daemon_socket (const char *socketname) +{ +#ifdef USE_RANDOM_DAEMON + if (daemon_socket_name) + BUG (); + + daemon_socket_name = gcry_xstrdup (socketname); +#else /*!USE_RANDOM_DAEMON*/ + (void)socketname; +#endif /*!USE_RANDOM_DAEMON*/ +} + +/* With ONOFF set to 1, enable the use of the daemon. With ONOFF set + to 0, disable the use of the daemon. With ONOF set to -1, return + whether the daemon has been enabled. */ +int +_gcry_rngcsprng_use_daemon (int onoff) +{ +#ifdef USE_RANDOM_DAEMON + int last; + + /* This is not really thread safe. However it is expected that this + function is being called during initialization and at that point + we are for other reasons not really thread safe. We do not want + to lock it because we might eventually decide that this function + may even be called prior to gcry_check_version. */ + last = allow_daemon; + if (onoff != -1) + allow_daemon = onoff; + + return last; +#else /*!USE_RANDOM_DAEMON*/ + (void)onoff; + return 0; +#endif /*!USE_RANDOM_DAEMON*/ +} + + +/* This function returns true if no real RNG is available or the + quality of the RNG has been degraded for test purposes. */ +int +_gcry_rngcsprng_is_faked (void) +{ + /* We need to initialize due to the runtime determination of + available entropy gather modules. */ + initialize(); + return quick_test; +} + + +/* 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. */ +gcry_error_t +_gcry_rngcsprng_add_bytes (const void *buf, size_t buflen, int quality) +{ + size_t nbytes; + const char *bufptr; + + if (quality == -1) + quality = 35; + else if (quality > 100) + quality = 100; + else if (quality < 0) + quality = 0; + + if (!buf) + return gpg_error (GPG_ERR_INV_ARG); + + if (!buflen || quality < 10) + return 0; /* Take a shortcut. */ + + /* Because we don't increment the entropy estimation with FASTPOLL, + we don't need to take lock that estimation while adding from an + external source. This limited entropy estimation also means that + we can't take QUALITY into account. */ + initialize_basics (); + bufptr = buf; + while (buflen) + { + nbytes = buflen > POOLSIZE? POOLSIZE : buflen; + lock_pool (); + if (rndpool) + add_randomness (bufptr, nbytes, RANDOM_ORIGIN_EXTERNAL); + unlock_pool (); + bufptr += nbytes; + buflen -= nbytes; + } + return 0; +} + + +/* Public function to fill the buffer with LENGTH bytes of + cryptographically strong random bytes. Level GCRY_WEAK_RANDOM is + not very strong, GCRY_STRONG_RANDOM is strong enough for most + usage, GCRY_VERY_STRONG_RANDOM is good for key generation stuff but + may be very slow. */ +void +_gcry_rngcsprng_randomize (void *buffer, size_t length, + enum gcry_random_level level) +{ + unsigned char *p; + + /* Make sure we are initialized. */ + initialize (); + + /* Handle our hack used for regression tests of Libgcrypt. */ + if ( quick_test && level > GCRY_STRONG_RANDOM ) + level = GCRY_STRONG_RANDOM; + + /* Make sure the level is okay. */ + level &= 3; + +#ifdef USE_RANDOM_DAEMON + if (allow_daemon + && !_gcry_daemon_randomize (daemon_socket_name, buffer, length, level)) + return; /* The daemon succeeded. */ + allow_daemon = 0; /* Daemon failed - switch off. */ +#endif /*USE_RANDOM_DAEMON*/ + + /* Acquire the pool lock. */ + lock_pool (); + + /* Update the statistics. */ + if (level >= GCRY_VERY_STRONG_RANDOM) + { + 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. */ + unlock_pool (); +} + + + + +/* + * Mix the 600 byte pool. Note that the 64 byte scratch area directly + * follows the pool. The numbers in the diagram give the number of + * bytes. + * <................600...............> <.64.> + * pool |------------------------------------| |------| + * <20><.24.> <20> + * | | +-----+ + * +-----|-------------------------------|-+ + * +-------------------------------|-|-+ + * v v v + * |------| + * <hash> + * +---------------------------------------+ + * v + * <20> + * pool' |------------------------------------| + * <20><20><.24.> + * +---|-----|---------------------------+ + * +-----|---------------------------|-+ + * +---------------------------|-|-+ + * v v v + * |------| + * <hash> + * | + * +-----------------------------------+ + * v + * <20> + * pool'' |------------------------------------| + * <20><20><20><.24.> + * +---|-----|-----------------------+ + * +-----|-----------------------|-+ + * +-----------------------|-|-+ + * v v v + * + * and so on until we did this for all 30 blocks. + * + * To better protect against implementation errors in this code, we + * xor a digest of the entire pool into the pool before mixing. + * + * Note: this function must only be called with a locked pool. + */ +static void +mix_pool(unsigned char *pool) +{ + static unsigned char failsafe_digest[DIGESTLEN]; + static int failsafe_digest_valid; + + unsigned char *hashbuf = pool + POOLSIZE; + unsigned char *p, *pend; + int i, n; + SHA1_CONTEXT md; + unsigned int nburn; + +#if DIGESTLEN != 20 +#error must have a digest length of 20 for SHA-1 +#endif + + gcry_assert (pool_is_locked); + _gcry_sha1_mixblock_init (&md); + + /* pool_0 -> pool'. */ + pend = pool + POOLSIZE; + memcpy (hashbuf, pend - DIGESTLEN, DIGESTLEN); + memcpy (hashbuf+DIGESTLEN, pool, BLOCKLEN-DIGESTLEN); + nburn = _gcry_sha1_mixblock (&md, hashbuf); + memcpy (pool, hashbuf, DIGESTLEN); + + if (failsafe_digest_valid && pool == rndpool) + { + for (i=0; i < DIGESTLEN; i++) + pool[i] ^= failsafe_digest[i]; + } + + /* Loop for the remaining iterations. */ + p = pool; + for (n=1; n < POOLBLOCKS; n++) + { + if (p + BLOCKLEN < pend) + memcpy (hashbuf, p, BLOCKLEN); + else + { + unsigned char *pp = p; + + for (i=0; i < BLOCKLEN; i++ ) + { + if ( pp >= pend ) + pp = pool; + hashbuf[i] = *pp++; + } + } + + _gcry_sha1_mixblock (&md, hashbuf); + p += DIGESTLEN; + memcpy (p, hashbuf, DIGESTLEN); + } + + /* 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 ( pool == rndpool) + { + _gcry_sha1_hash_buffer (failsafe_digest, pool, POOLSIZE); + failsafe_digest_valid = 1; + } + + _gcry_burn_stack (nburn); +} + + +void +_gcry_rngcsprng_set_seed_file (const char *name) +{ + if (seed_file_name) + BUG (); + seed_file_name = xstrdup (name); +} + + + +/* Helper for my_open. + * Return a malloced wide char string from an UTF-8 encoded input + * string STRING. Caller must free this value. Returns NULL and sets + * ERRNO on failure. Calling this function with STRING set to NULL is + * not defined. */ +#ifdef HAVE_W32_SYSTEM +static wchar_t * +utf8_to_wchar (const char *string) +{ + int n; + size_t nbytes; + wchar_t *result; + + n = MultiByteToWideChar (CP_UTF8, 0, string, -1, NULL, 0); + if (n < 0) + { + gpg_err_set_errno (EINVAL); + return NULL; + } + + nbytes = (size_t)(n+1) * sizeof(*result); + if (nbytes / sizeof(*result) != (n+1)) + { + gpg_err_set_errno (ENOMEM); + return NULL; + } + result = xtrymalloc (nbytes); + if (!result) + return NULL; + + n = MultiByteToWideChar (CP_UTF8, 0, string, -1, result, n); + if (n < 0) + { + xfree (result); + gpg_err_set_errno (EINVAL); + result = NULL; + } + return result; +} +#endif /*HAVE_W32_SYSTEM*/ + + +/* Helper for my_open. */ +#ifdef HAVE_W32_SYSTEM +static int +any8bitchar (const char *string) +{ + if (string) + for ( ; *string; string++) + if ((*string & 0x80)) + return 1; + return 0; +} +#endif /*HAVE_W32_SYSTEM*/ + + +/* A wrapper around open to handle Unicode file names under Windows. */ +static int +my_open (const char *name, int flags, unsigned int mode) +{ +#ifdef HAVE_W32_SYSTEM + if (any8bitchar (name)) + { + wchar_t *wname; + int ret; + + wname = utf8_to_wchar (name); + if (!wname) + return -1; + ret = _wopen (wname, flags, mode); + xfree (wname); + return ret; + } + else + return open (name, flags, mode); +#else + return open (name, flags, mode); +#endif +} + + +/* Lock an open file identified by file descriptor FD and wait a + reasonable time to succeed. With FOR_WRITE set to true a write + lock will be taken. FNAME is used only for diagnostics. Returns 0 + on success or -1 on error. */ +static int +lock_seed_file (int fd, const char *fname, int for_write) +{ +#ifdef __GCC__ +#warning Check whether we can lock on Windows. +#endif +#if LOCK_SEED_FILE + struct flock lck; + struct timeval tv; + int backoff=0; + + /* We take a lock on the entire file. */ + memset (&lck, 0, sizeof lck); + lck.l_type = for_write? F_WRLCK : F_RDLCK; + lck.l_whence = SEEK_SET; + + while (fcntl (fd, F_SETLK, &lck) == -1) + { + if (errno != EAGAIN && errno != EACCES) + { + log_info (_("can't lock `%s': %s\n"), fname, strerror (errno)); + return -1; + } + + if (backoff > 2) /* Show the first message after ~2.25 seconds. */ + log_info( _("waiting for lock on `%s'...\n"), fname); + + tv.tv_sec = backoff; + tv.tv_usec = 250000; + select (0, NULL, NULL, NULL, &tv); + if (backoff < 10) + backoff++ ; + } +#endif /*!LOCK_SEED_FILE*/ + return 0; +} + + +/* Read in a seed from the random_seed file and return true if this + was successful. + + Note: Multiple instances of applications sharing the same random + seed file can be started in parallel, in which case they will read + out the same pool and then race for updating it (the last update + overwrites earlier updates). They will differentiate only by the + weak entropy that is added in read_seed_file based on the PID and + clock, and up to 32 bytes from a non-blocking entropy source. The + consequence is that the output of these different instances is + correlated to some extent. In the perfect scenario, the attacker + can control (or at least guess) the PID and clock of the + application, and drain the system's entropy pool to reduce the "up + to 32 bytes" above to 0. Then the dependencies of the initial + states of the pools are completely known. */ +static int +read_seed_file (void) +{ + int fd; + struct stat sb; + unsigned char buffer[POOLSIZE]; + int n; + + gcry_assert (pool_is_locked); + + if (!seed_file_name) + return 0; + +#ifdef HAVE_DOSISH_SYSTEM + fd = my_open (seed_file_name, O_RDONLY | O_BINARY, 0); +#else + fd = my_open (seed_file_name, O_RDONLY, 0); +#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 (lock_seed_file (fd, seed_file_name, 0)) + { + close (fd); + 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, RANDOM_ORIGIN_INIT ); + /* add some minor entropy to the pool now (this will also force a mixing) */ + { + pid_t x = getpid(); + add_randomness( &x, sizeof(x), RANDOM_ORIGIN_INIT ); + } + { + time_t x = time(NULL); + add_randomness( &x, sizeof(x), RANDOM_ORIGIN_INIT ); + } + { + clock_t x = clock(); + add_randomness( &x, sizeof(x), RANDOM_ORIGIN_INIT ); + } + + /* And read a few bytes from our entropy source. If we have the + * Jitter RNG we can fast get a lot of entropy. Thus we read 1024 + * bits from that source. + * + * Without the Jitter RNG we keep the old method of reading only a + * few bytes usually from /dev/urandom which won't block. */ + if (_gcry_rndjent_get_version (NULL)) + read_random_source (RANDOM_ORIGIN_INIT, 128, GCRY_STRONG_RANDOM); + else + read_random_source (RANDOM_ORIGIN_INIT, 32, GCRY_STRONG_RANDOM); + + allow_seed_file_update = 1; + return 1; +} + + +void +_gcry_rngcsprng_update_seed_file (void) +{ + unsigned long *sp, *dp; + int fd, i; + + /* We do only a basic initialization so that we can lock the pool. + This is required to cope with the case that this function is + called by some cleanup code at a point where the RNG has never + been initialized. */ + initialize_basics (); + lock_pool (); + + if ( !seed_file_name || !rndpool || !pool_filled ) + { + unlock_pool (); + return; + } + if ( !allow_seed_file_update ) + { + unlock_pool (); + log_info(_("note: random_seed file not updated\n")); + return; + } + + /* At this point we know that there is something in the pool and + thus we can conclude that the pool has been fully initialized. */ + + + /* Copy the entropy pool to a scratch pool and mix both of them. */ + for (i=0,dp=(unsigned long*)(void*)keypool, sp=(unsigned long*)(void*)rndpool; + i < POOLWORDS; i++, dp++, sp++ ) + { + *dp = *sp + ADD_VALUE; + } + mix_pool(rndpool); rndstats.mixrnd++; + mix_pool(keypool); rndstats.mixkey++; + +#if defined(HAVE_DOSISH_SYSTEM) || defined(__CYGWIN__) + fd = my_open (seed_file_name, O_WRONLY|O_CREAT|O_TRUNC|O_BINARY, + S_IRUSR|S_IWUSR ); +#else +# if LOCK_SEED_FILE + fd = my_open (seed_file_name, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR ); +# else + fd = my_open (seed_file_name, O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR ); +# endif +#endif + + if (fd == -1 ) + log_info (_("can't create `%s': %s\n"), seed_file_name, strerror(errno) ); + else if (lock_seed_file (fd, seed_file_name, 1)) + { + close (fd); + } +#if LOCK_SEED_FILE + else if (ftruncate (fd, 0)) + { + log_info(_("can't write `%s': %s\n"), seed_file_name, strerror(errno)); + close (fd); + } +#endif /*LOCK_SEED_FILE*/ + 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)); + } + + unlock_pool (); +} + + +/* Read random out of the pool. This function is the core of the + public random functions. Note that Level GCRY_WEAK_RANDOM is not + anymore handled special and in fact is an alias in the API for + level GCRY_STRONG_RANDOM. Must be called with the pool already + locked. */ +static void +read_pool (byte *buffer, size_t length, int level) +{ + int i; + unsigned long *sp, *dp; + /* The volatile is there to make sure the compiler does not optimize + the code away in case the getpid function is badly attributed. + Note that we keep a pid in a static variable as well as in a + stack based one; the latter is to detect ill behaving thread + libraries, ignoring the pool mutexes. */ + static volatile pid_t my_pid = (pid_t)(-1); + volatile pid_t my_pid2; + + gcry_assert (pool_is_locked); + + retry: + /* Get our own pid, so that we can detect a fork. */ + my_pid2 = getpid (); + if (my_pid == (pid_t)(-1)) + my_pid = my_pid2; + if ( my_pid != my_pid2 ) + { + /* We detected a plain fork; i.e. we are now the child. Update + the static pid and add some randomness. */ + pid_t x; + + my_pid = my_pid2; + x = my_pid; + add_randomness (&x, sizeof(x), RANDOM_ORIGIN_INIT); + just_mixed = 0; /* Make sure it will get mixed. */ + } + + gcry_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 == GCRY_VERY_STRONG_RANDOM && !did_initial_extra_seeding) + { + size_t needed; + + pool_balance = 0; + needed = length - pool_balance; + if (needed < 16) /* At least 128 bits. */ + needed = 16; + else if( needed > POOLSIZE ) + BUG (); + read_random_source (RANDOM_ORIGIN_EXTRAPOLL, needed, + GCRY_VERY_STRONG_RANDOM); + pool_balance += needed; + did_initial_extra_seeding = 1; + } + + /* For level 2 make sure that there is enough random in the pool. */ + if (level == GCRY_VERY_STRONG_RANDOM && pool_balance < length) + { + size_t needed; + + if (pool_balance < 0) + pool_balance = 0; + needed = length - pool_balance; + if (needed > POOLSIZE) + BUG (); + read_random_source (RANDOM_ORIGIN_EXTRAPOLL, needed, + GCRY_VERY_STRONG_RANDOM); + 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 pid in so that we for sure won't deliver the same random + after a fork. */ + { + pid_t apid = my_pid; + add_randomness (&apid, sizeof (apid), RANDOM_ORIGIN_INIT); + } + + /* 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=(unsigned long*)(void*)keypool, sp=(unsigned long*)(void*)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 requested data. We use a read pointer 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. This test here is to detect forks + in a multi-threaded process. It does not work with all thread + implementations in particular not with pthreads. However it is + good enough for GNU Pth. */ + if ( getpid () != my_pid2 ) + { + pid_t x = getpid(); + add_randomness (&x, sizeof(x), RANDOM_ORIGIN_INIT); + just_mixed = 0; /* Make sure it will get mixed. */ + my_pid = x; /* Also update the static pid. */ + goto retry; + } +} + + + +/* Add LENGTH bytes of randomness from buffer to the pool. ORIGIN is + used to specify the randomness origin. This is one of the + RANDOM_ORIGIN_* values. */ +static void +add_randomness (const void *buffer, size_t length, enum random_origins origin) +{ + const unsigned char *p = buffer; + size_t count = 0; + + gcry_assert (pool_is_locked); + + rndstats.addbytes += length; + rndstats.naddbytes++; + while (length-- ) + { + rndpool[pool_writepos++] ^= *p++; + count++; + if (pool_writepos >= POOLSIZE ) + { + /* It is possible that we are invoked before the pool is + filled using an unreliable origin of entropy, for example + the fast random poll. To avoid flagging the pool as + filled in this case, we track the initial filling state + separately. See also the remarks about the seed file. */ + if (origin >= RANDOM_ORIGIN_SLOWPOLL && !pool_filled) + { + pool_filled_counter += count; + count = 0; + if (pool_filled_counter >= POOLSIZE) + pool_filled = 1; + } + pool_writepos = 0; + mix_pool(rndpool); rndstats.mixrnd++; + just_mixed = !length; + } + } +} + + + +static void +random_poll() +{ + rndstats.slowpolls++; + read_random_source (RANDOM_ORIGIN_SLOWPOLL, POOLSIZE/5, GCRY_STRONG_RANDOM); +} + + +/* Runtime determination of the slow entropy gathering module. */ +static int (* +getfnc_gather_random (void))(void (*)(const void*, size_t, + enum random_origins), + enum random_origins, size_t, int) +{ + int (*fnc)(void (*)(const void*, size_t, enum random_origins), + enum random_origins, size_t, int); + +#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 + +#if USE_RNDW32CE + fnc = _gcry_rndw32ce_gather_random; + return fnc; +#endif + + log_fatal (_("no entropy gathering module detected\n")); + + return NULL; /*NOTREACHED*/ +} + +/* Runtime determination of the fast entropy gathering function. + (Currently a compile time method is used.) */ +static void (* +getfnc_fast_random_poll (void))( void (*)(const void*, size_t, + enum random_origins), + enum random_origins) +{ +#if USE_RNDW32 + return _gcry_rndw32_gather_random_fast; +#endif +#if USE_RNDW32CE + return _gcry_rndw32ce_gather_random_fast; +#endif + return NULL; +} + + + +static void +do_fast_random_poll (void) +{ + gcry_assert (pool_is_locked); + + rndstats.fastpolls++; + + if (fast_gather_fnc) + fast_gather_fnc (add_randomness, RANDOM_ORIGIN_FASTPOLL); + + /* Continue with the generic functions. */ +#if HAVE_GETHRTIME + { + hrtime_t tv; + tv = gethrtime(); + add_randomness( &tv, sizeof(tv), RANDOM_ORIGIN_FASTPOLL ); + } +#elif HAVE_GETTIMEOFDAY + { + struct timeval tv; + if( gettimeofday( &tv, NULL ) ) + BUG(); + add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), RANDOM_ORIGIN_FASTPOLL ); + add_randomness( &tv.tv_usec, sizeof(tv.tv_usec), RANDOM_ORIGIN_FASTPOLL ); + } +#elif HAVE_CLOCK_GETTIME + { struct timespec tv; + if( clock_gettime( CLOCK_REALTIME, &tv ) == -1 ) + BUG(); + add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), RANDOM_ORIGIN_FASTPOLL ); + add_randomness( &tv.tv_nsec, sizeof(tv.tv_nsec), RANDOM_ORIGIN_FASTPOLL ); + } +#else /* use times */ +# ifndef HAVE_DOSISH_SYSTEM + { struct tms buf; + times( &buf ); + add_randomness( &buf, sizeof buf, RANDOM_ORIGIN_FASTPOLL ); + } +# 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 + ignore all error codes and hope for the best. */ + getrusage (RUSAGE_SELF, &buf ); + add_randomness( &buf, sizeof buf, RANDOM_ORIGIN_FASTPOLL ); + 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 available 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), RANDOM_ORIGIN_FASTPOLL ); + } + { + clock_t x = clock(); + add_randomness( &x, sizeof(x), RANDOM_ORIGIN_FASTPOLL ); + } + + /* If the system features a fast hardware RNG, read some bytes from + there. */ + _gcry_rndhw_poll_fast (add_randomness, RANDOM_ORIGIN_FASTPOLL); +} + + +/* The fast random pool function as called at some places in + libgcrypt. This is merely a wrapper to make sure that this module + is initialized and to lock the pool. Note, that this function is a + NOP unless a random function has been used or _gcry_initialize (1) + has been used. We use this hack so that the internal use of this + function in cipher_open and md_open won't start filling up the + random pool, even if no random will be required by the process. */ +void +_gcry_rngcsprng_fast_poll (void) +{ + initialize_basics (); + + lock_pool (); + if (rndpool) + { + /* Yes, we are fully initialized. */ + do_fast_random_poll (); + } + unlock_pool (); +} + + + +static void +read_random_source (enum random_origins origin, size_t length, int level) +{ + if ( !slow_gather_fnc ) + log_fatal ("Slow entropy gathering module not yet initialized\n"); + + if (slow_gather_fnc (add_randomness, origin, length, level) < 0) + log_fatal ("No way to gather entropy for the RNG\n"); +} |