123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667 |
- /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
- *
- * Licensed under the OpenSSL license (the "License"). You may not use
- * this file except in compliance with the License. You can obtain a copy
- * in the file LICENSE in the source distribution or at
- * https://www.openssl.org/source/license.html
- */
- #include <stdio.h>
- #include <string.h>
- #include "e_os.h"
- #if !(defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_DSPBIOS))
- # include <sys/time.h>
- #endif
- #if defined(OPENSSL_SYS_VXWORKS)
- # include <time.h>
- #endif
- #include <openssl/opensslconf.h>
- #include <openssl/crypto.h>
- #include <openssl/rand.h>
- #include <openssl/async.h>
- #include "rand_lcl.h"
- #include <openssl/err.h>
- #include <internal/thread_once.h>
- #if defined(BN_DEBUG) || defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
- # define PREDICT
- #endif
- /* #define PREDICT 1 */
- #define STATE_SIZE 1023
- static size_t state_num = 0, state_index = 0;
- static unsigned char state[STATE_SIZE + MD_DIGEST_LENGTH];
- static unsigned char md[MD_DIGEST_LENGTH];
- static long md_count[2] = { 0, 0 };
- static double entropy = 0;
- static int initialized = 0;
- static CRYPTO_RWLOCK *rand_lock = NULL;
- static CRYPTO_RWLOCK *rand_tmp_lock = NULL;
- static CRYPTO_ONCE rand_lock_init = CRYPTO_ONCE_STATIC_INIT;
- /* May be set only when a thread holds rand_lock (to prevent double locking) */
- static unsigned int crypto_lock_rand = 0;
- /* access to locking_threadid is synchronized by rand_tmp_lock */
- /* valid iff crypto_lock_rand is set */
- static CRYPTO_THREAD_ID locking_threadid;
- #ifdef PREDICT
- int rand_predictable = 0;
- #endif
- static int rand_hw_seed(EVP_MD_CTX *ctx);
- static void rand_cleanup(void);
- static int rand_seed(const void *buf, int num);
- static int rand_add(const void *buf, int num, double add_entropy);
- static int rand_bytes(unsigned char *buf, int num, int pseudo);
- static int rand_nopseudo_bytes(unsigned char *buf, int num);
- #if OPENSSL_API_COMPAT < 0x10100000L
- static int rand_pseudo_bytes(unsigned char *buf, int num);
- #endif
- static int rand_status(void);
- static RAND_METHOD rand_meth = {
- rand_seed,
- rand_nopseudo_bytes,
- rand_cleanup,
- rand_add,
- #if OPENSSL_API_COMPAT < 0x10100000L
- rand_pseudo_bytes,
- #else
- NULL,
- #endif
- rand_status
- };
- DEFINE_RUN_ONCE_STATIC(do_rand_lock_init)
- {
- OPENSSL_init_crypto(0, NULL);
- rand_lock = CRYPTO_THREAD_lock_new();
- rand_tmp_lock = CRYPTO_THREAD_lock_new();
- return rand_lock != NULL && rand_tmp_lock != NULL;
- }
- RAND_METHOD *RAND_OpenSSL(void)
- {
- return (&rand_meth);
- }
- static void rand_cleanup(void)
- {
- OPENSSL_cleanse(state, sizeof(state));
- state_num = 0;
- state_index = 0;
- OPENSSL_cleanse(md, MD_DIGEST_LENGTH);
- md_count[0] = 0;
- md_count[1] = 0;
- entropy = 0;
- initialized = 0;
- CRYPTO_THREAD_lock_free(rand_lock);
- CRYPTO_THREAD_lock_free(rand_tmp_lock);
- }
- static int rand_add(const void *buf, int num, double add)
- {
- int i, j, k, st_idx;
- long md_c[2];
- unsigned char local_md[MD_DIGEST_LENGTH];
- EVP_MD_CTX *m;
- int do_not_lock;
- int rv = 0;
- if (!num)
- return 1;
- #ifdef PREDICT
- if (rand_predictable)
- return 1;
- #endif
- /*
- * (Based on the rand(3) manpage)
- *
- * The input is chopped up into units of 20 bytes (or less for
- * the last block). Each of these blocks is run through the hash
- * function as follows: The data passed to the hash function
- * is the current 'md', the same number of bytes from the 'state'
- * (the location determined by in incremented looping index) as
- * the current 'block', the new key data 'block', and 'count'
- * (which is incremented after each use).
- * The result of this is kept in 'md' and also xored into the
- * 'state' at the same locations that were used as input into the
- * hash function.
- */
- m = EVP_MD_CTX_new();
- if (m == NULL)
- goto err;
- if (!RUN_ONCE(&rand_lock_init, do_rand_lock_init))
- goto err;
- /* check if we already have the lock */
- if (crypto_lock_rand) {
- CRYPTO_THREAD_ID cur = CRYPTO_THREAD_get_current_id();
- CRYPTO_THREAD_read_lock(rand_tmp_lock);
- do_not_lock = CRYPTO_THREAD_compare_id(locking_threadid, cur);
- CRYPTO_THREAD_unlock(rand_tmp_lock);
- } else
- do_not_lock = 0;
- if (!do_not_lock)
- CRYPTO_THREAD_write_lock(rand_lock);
- st_idx = state_index;
- /*
- * use our own copies of the counters so that even if a concurrent thread
- * seeds with exactly the same data and uses the same subarray there's
- * _some_ difference
- */
- md_c[0] = md_count[0];
- md_c[1] = md_count[1];
- memcpy(local_md, md, sizeof md);
- /* state_index <= state_num <= STATE_SIZE */
- state_index += num;
- if (state_index >= STATE_SIZE) {
- state_index %= STATE_SIZE;
- state_num = STATE_SIZE;
- } else if (state_num < STATE_SIZE) {
- if (state_index > state_num)
- state_num = state_index;
- }
- /* state_index <= state_num <= STATE_SIZE */
- /*
- * state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
- * will use now, but other threads may use them as well
- */
- md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
- if (!do_not_lock)
- CRYPTO_THREAD_unlock(rand_lock);
- for (i = 0; i < num; i += MD_DIGEST_LENGTH) {
- j = (num - i);
- j = (j > MD_DIGEST_LENGTH) ? MD_DIGEST_LENGTH : j;
- if (!MD_Init(m))
- goto err;
- if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
- goto err;
- k = (st_idx + j) - STATE_SIZE;
- if (k > 0) {
- if (!MD_Update(m, &(state[st_idx]), j - k))
- goto err;
- if (!MD_Update(m, &(state[0]), k))
- goto err;
- } else if (!MD_Update(m, &(state[st_idx]), j))
- goto err;
- /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
- if (!MD_Update(m, buf, j))
- goto err;
- /*
- * We know that line may cause programs such as purify and valgrind
- * to complain about use of uninitialized data. The problem is not,
- * it's with the caller. Removing that line will make sure you get
- * really bad randomness and thereby other problems such as very
- * insecure keys.
- */
- if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
- goto err;
- if (!MD_Final(m, local_md))
- goto err;
- md_c[1]++;
- buf = (const char *)buf + j;
- for (k = 0; k < j; k++) {
- /*
- * Parallel threads may interfere with this, but always each byte
- * of the new state is the XOR of some previous value of its and
- * local_md (intermediate values may be lost). Alway using locking
- * could hurt performance more than necessary given that
- * conflicts occur only when the total seeding is longer than the
- * random state.
- */
- state[st_idx++] ^= local_md[k];
- if (st_idx >= STATE_SIZE)
- st_idx = 0;
- }
- }
- if (!do_not_lock)
- CRYPTO_THREAD_write_lock(rand_lock);
- /*
- * Don't just copy back local_md into md -- this could mean that other
- * thread's seeding remains without effect (except for the incremented
- * counter). By XORing it we keep at least as much entropy as fits into
- * md.
- */
- for (k = 0; k < (int)sizeof(md); k++) {
- md[k] ^= local_md[k];
- }
- if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
- entropy += add;
- if (!do_not_lock)
- CRYPTO_THREAD_unlock(rand_lock);
- rv = 1;
- err:
- EVP_MD_CTX_free(m);
- return rv;
- }
- static int rand_seed(const void *buf, int num)
- {
- return rand_add(buf, num, (double)num);
- }
- static int rand_bytes(unsigned char *buf, int num, int pseudo)
- {
- static volatile int stirred_pool = 0;
- int i, j, k;
- size_t num_ceil, st_idx, st_num;
- int ok;
- long md_c[2];
- unsigned char local_md[MD_DIGEST_LENGTH];
- EVP_MD_CTX *m;
- #ifndef GETPID_IS_MEANINGLESS
- pid_t curr_pid = getpid();
- #endif
- time_t curr_time = time(NULL);
- int do_stir_pool = 0;
- /* time value for various platforms */
- #ifdef OPENSSL_SYS_WIN32
- FILETIME tv;
- # ifdef _WIN32_WCE
- SYSTEMTIME t;
- GetSystemTime(&t);
- SystemTimeToFileTime(&t, &tv);
- # else
- GetSystemTimeAsFileTime(&tv);
- # endif
- #elif defined(OPENSSL_SYS_VXWORKS)
- struct timespec tv;
- clock_gettime(CLOCK_REALTIME, &ts);
- #elif defined(OPENSSL_SYS_DSPBIOS)
- unsigned long long tv, OPENSSL_rdtsc();
- tv = OPENSSL_rdtsc();
- #else
- struct timeval tv;
- gettimeofday(&tv, NULL);
- #endif
- #ifdef PREDICT
- if (rand_predictable) {
- unsigned char val = 1;
- for (i = 0; i < num; i++)
- buf[i] = val++;
- return (1);
- }
- #endif
- if (num <= 0)
- return 1;
- m = EVP_MD_CTX_new();
- if (m == NULL)
- goto err_mem;
- /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
- num_ceil =
- (1 + (num - 1) / (MD_DIGEST_LENGTH / 2)) * (MD_DIGEST_LENGTH / 2);
- /*
- * (Based on the rand(3) manpage:)
- *
- * For each group of 10 bytes (or less), we do the following:
- *
- * Input into the hash function the local 'md' (which is initialized from
- * the global 'md' before any bytes are generated), the bytes that are to
- * be overwritten by the random bytes, and bytes from the 'state'
- * (incrementing looping index). From this digest output (which is kept
- * in 'md'), the top (up to) 10 bytes are returned to the caller and the
- * bottom 10 bytes are xored into the 'state'.
- *
- * Finally, after we have finished 'num' random bytes for the
- * caller, 'count' (which is incremented) and the local and global 'md'
- * are fed into the hash function and the results are kept in the
- * global 'md'.
- */
- if (!RUN_ONCE(&rand_lock_init, do_rand_lock_init))
- goto err_mem;
- CRYPTO_THREAD_write_lock(rand_lock);
- /*
- * We could end up in an async engine while holding this lock so ensure
- * we don't pause and cause a deadlock
- */
- ASYNC_block_pause();
- /* prevent rand_bytes() from trying to obtain the lock again */
- CRYPTO_THREAD_write_lock(rand_tmp_lock);
- locking_threadid = CRYPTO_THREAD_get_current_id();
- CRYPTO_THREAD_unlock(rand_tmp_lock);
- crypto_lock_rand = 1;
- if (!initialized) {
- RAND_poll();
- initialized = 1;
- }
- if (!stirred_pool)
- do_stir_pool = 1;
- ok = (entropy >= ENTROPY_NEEDED);
- if (!ok) {
- /*
- * If the PRNG state is not yet unpredictable, then seeing the PRNG
- * output may help attackers to determine the new state; thus we have
- * to decrease the entropy estimate. Once we've had enough initial
- * seeding we don't bother to adjust the entropy count, though,
- * because we're not ambitious to provide *information-theoretic*
- * randomness. NOTE: This approach fails if the program forks before
- * we have enough entropy. Entropy should be collected in a separate
- * input pool and be transferred to the output pool only when the
- * entropy limit has been reached.
- */
- entropy -= num;
- if (entropy < 0)
- entropy = 0;
- }
- if (do_stir_pool) {
- /*
- * In the output function only half of 'md' remains secret, so we
- * better make sure that the required entropy gets 'evenly
- * distributed' through 'state', our randomness pool. The input
- * function (rand_add) chains all of 'md', which makes it more
- * suitable for this purpose.
- */
- int n = STATE_SIZE; /* so that the complete pool gets accessed */
- while (n > 0) {
- #if MD_DIGEST_LENGTH > 20
- # error "Please adjust DUMMY_SEED."
- #endif
- #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
- /*
- * Note that the seed does not matter, it's just that
- * rand_add expects to have something to hash.
- */
- rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
- n -= MD_DIGEST_LENGTH;
- }
- if (ok)
- stirred_pool = 1;
- }
- st_idx = state_index;
- st_num = state_num;
- md_c[0] = md_count[0];
- md_c[1] = md_count[1];
- memcpy(local_md, md, sizeof md);
- state_index += num_ceil;
- if (state_index > state_num)
- state_index %= state_num;
- /*
- * state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] are now
- * ours (but other threads may use them too)
- */
- md_count[0] += 1;
- /* before unlocking, we must clear 'crypto_lock_rand' */
- crypto_lock_rand = 0;
- ASYNC_unblock_pause();
- CRYPTO_THREAD_unlock(rand_lock);
- while (num > 0) {
- /* num_ceil -= MD_DIGEST_LENGTH/2 */
- j = (num >= MD_DIGEST_LENGTH / 2) ? MD_DIGEST_LENGTH / 2 : num;
- num -= j;
- if (!MD_Init(m))
- goto err;
- #ifndef GETPID_IS_MEANINGLESS
- if (curr_pid) { /* just in the first iteration to save time */
- if (!MD_Update(m, (unsigned char *)&curr_pid, sizeof curr_pid))
- goto err;
- curr_pid = 0;
- }
- #endif
- if (curr_time) { /* just in the first iteration to save time */
- if (!MD_Update(m, (unsigned char *)&curr_time, sizeof curr_time))
- goto err;
- if (!MD_Update(m, (unsigned char *)&tv, sizeof tv))
- goto err;
- curr_time = 0;
- if (!rand_hw_seed(m))
- goto err;
- }
- if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
- goto err;
- if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
- goto err;
- k = (st_idx + MD_DIGEST_LENGTH / 2) - st_num;
- if (k > 0) {
- if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2 - k))
- goto err;
- if (!MD_Update(m, &(state[0]), k))
- goto err;
- } else if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2))
- goto err;
- if (!MD_Final(m, local_md))
- goto err;
- for (i = 0; i < MD_DIGEST_LENGTH / 2; i++) {
- /* may compete with other threads */
- state[st_idx++] ^= local_md[i];
- if (st_idx >= st_num)
- st_idx = 0;
- if (i < j)
- *(buf++) = local_md[i + MD_DIGEST_LENGTH / 2];
- }
- }
- if (!MD_Init(m)
- || !MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c))
- || !MD_Update(m, local_md, MD_DIGEST_LENGTH))
- goto err;
- CRYPTO_THREAD_write_lock(rand_lock);
- /*
- * Prevent deadlocks if we end up in an async engine
- */
- ASYNC_block_pause();
- if (!MD_Update(m, md, MD_DIGEST_LENGTH) || !MD_Final(m, md)) {
- CRYPTO_THREAD_unlock(rand_lock);
- goto err;
- }
- ASYNC_unblock_pause();
- CRYPTO_THREAD_unlock(rand_lock);
- EVP_MD_CTX_free(m);
- if (ok)
- return (1);
- else if (pseudo)
- return 0;
- else {
- RANDerr(RAND_F_RAND_BYTES, RAND_R_PRNG_NOT_SEEDED);
- ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
- "https://www.openssl.org/docs/faq.html");
- return (0);
- }
- err:
- RANDerr(RAND_F_RAND_BYTES, ERR_R_EVP_LIB);
- EVP_MD_CTX_free(m);
- return 0;
- err_mem:
- RANDerr(RAND_F_RAND_BYTES, ERR_R_MALLOC_FAILURE);
- EVP_MD_CTX_free(m);
- return 0;
- }
- static int rand_nopseudo_bytes(unsigned char *buf, int num)
- {
- return rand_bytes(buf, num, 0);
- }
- #if OPENSSL_API_COMPAT < 0x10100000L
- /*
- * pseudo-random bytes that are guaranteed to be unique but not unpredictable
- */
- static int rand_pseudo_bytes(unsigned char *buf, int num)
- {
- return rand_bytes(buf, num, 1);
- }
- #endif
- static int rand_status(void)
- {
- CRYPTO_THREAD_ID cur;
- int ret;
- int do_not_lock;
- if (!RUN_ONCE(&rand_lock_init, do_rand_lock_init))
- return 0;
- cur = CRYPTO_THREAD_get_current_id();
- /*
- * check if we already have the lock (could happen if a RAND_poll()
- * implementation calls RAND_status())
- */
- if (crypto_lock_rand) {
- CRYPTO_THREAD_read_lock(rand_tmp_lock);
- do_not_lock = CRYPTO_THREAD_compare_id(locking_threadid, cur);
- CRYPTO_THREAD_unlock(rand_tmp_lock);
- } else
- do_not_lock = 0;
- if (!do_not_lock) {
- CRYPTO_THREAD_write_lock(rand_lock);
- /*
- * Prevent deadlocks in case we end up in an async engine
- */
- ASYNC_block_pause();
- /*
- * prevent rand_bytes() from trying to obtain the lock again
- */
- CRYPTO_THREAD_write_lock(rand_tmp_lock);
- locking_threadid = cur;
- CRYPTO_THREAD_unlock(rand_tmp_lock);
- crypto_lock_rand = 1;
- }
- if (!initialized) {
- RAND_poll();
- initialized = 1;
- }
- ret = entropy >= ENTROPY_NEEDED;
- if (!do_not_lock) {
- /* before unlocking, we must clear 'crypto_lock_rand' */
- crypto_lock_rand = 0;
- ASYNC_unblock_pause();
- CRYPTO_THREAD_unlock(rand_lock);
- }
- return ret;
- }
- /*
- * rand_hw_seed: get seed data from any available hardware RNG. only
- * currently supports rdrand.
- */
- /* Adapted from eng_rdrand.c */
- #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
- defined(__x86_64) || defined(__x86_64__) || \
- defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ) \
- && !defined(OPENSSL_NO_RDRAND)
- # define RDRAND_CALLS 4
- size_t OPENSSL_ia32_rdrand(void);
- extern unsigned int OPENSSL_ia32cap_P[];
- static int rand_hw_seed(EVP_MD_CTX *ctx)
- {
- int i;
- if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
- return 1;
- for (i = 0; i < RDRAND_CALLS; i++) {
- size_t rnd;
- rnd = OPENSSL_ia32_rdrand();
- if (rnd == 0)
- return 1;
- if (!MD_Update(ctx, (unsigned char *)&rnd, sizeof(size_t)))
- return 0;
- }
- return 1;
- }
- /* XOR an existing buffer with random data */
- void rand_hw_xor(unsigned char *buf, size_t num)
- {
- size_t rnd;
- if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
- return;
- while (num >= sizeof(size_t)) {
- rnd = OPENSSL_ia32_rdrand();
- if (rnd == 0)
- return;
- *((size_t *)buf) ^= rnd;
- buf += sizeof(size_t);
- num -= sizeof(size_t);
- }
- if (num) {
- rnd = OPENSSL_ia32_rdrand();
- if (rnd == 0)
- return;
- while (num) {
- *buf ^= rnd & 0xff;
- rnd >>= 8;
- buf++;
- num--;
- }
- }
- }
- #else
- static int rand_hw_seed(EVP_MD_CTX *ctx)
- {
- return 1;
- }
- void rand_hw_xor(unsigned char *buf, size_t num)
- {
- return;
- }
- #endif
|