void rand_bytes(uint8_t *buf, int size) { uint8_t hash[MD_LEN]; int carry, len = (RAND_SIZE - 1)/2; ctx_t *ctx = core_get(); if (sizeof(int) > 2 && size > (1 << 16)) { THROW(ERR_NO_VALID); } /* buf = hash_gen(size) */ rand_gen(buf, size); /* H = hash(03 || V) */ ctx->rand[0] = 0x3; md_map(hash, ctx->rand, 1 + len); /* V = V + H + C + reseed_counter. */ rand_add(ctx->rand + 1, ctx->rand + 1 + len, len); carry = rand_add(ctx->rand + 1 + (len - MD_LEN), hash, MD_LEN); rand_inc(ctx->rand, len - MD_LEN + 1, carry); rand_inc(ctx->rand, len + 1, ctx->counter); ctx->counter = ctx->counter + 1; }
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) { static unsigned char val = 0; 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_seed(const void *buf, int num) { return rand_add(buf, num, (double)num); }