X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frand%2Frand_lib.c;h=0d1e3f6a07eb8f00ddfe4f5848ac5894d9b08de5;hp=3168d84b4796bcc20bd70136e16d432b39004e13;hb=9d951a7872e5fa2b2a83fe8cfda3af5c52581172;hpb=63f483e10d4e04158be234ed431e9f03d707ad82 diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c index 3168d84b47..0d1e3f6a07 100644 --- a/crypto/rand/rand_lib.c +++ b/crypto/rand/rand_lib.c @@ -1,5 +1,5 @@ /* - * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2017 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 @@ -24,17 +24,215 @@ static CRYPTO_RWLOCK *rand_engine_lock; static CRYPTO_RWLOCK *rand_meth_lock; static const RAND_METHOD *default_RAND_meth; static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT; +RAND_BYTES_BUFFER rand_bytes; +int rand_fork_count; +#ifdef OPENSSL_RAND_SEED_RDTSC +/* + * IMPORTANT NOTE: It is not currently possible to use this code + * because we are not sure about the amount of randomness it provides. + * Some SP900 tests have been run, but there is internal skepticism. + * So for now this code is not used. + */ +# error "RDTSC enabled? Should not be possible!" + +/* + * Since we get some randomness from the low-order bits of the + * high-speec clock, it can help. But don't return a status since + * it's not sufficient to indicate whether or not the seeding was + * done. + */ +void rand_read_tsc(RAND_poll_fn cb, void *arg) +{ + unsigned char c; + int i; + + if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) { + for (i = 0; i < TSC_READ_COUNT; i++) { + c = (unsigned char)(OPENSSL_rdtsc() & 0xFF); + cb(arg, &c, 1, 0.5); + } + } +} +#endif + +#ifdef OPENSSL_RAND_SEED_RDCPU +size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len); +size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len); + +extern unsigned int OPENSSL_ia32cap_P[]; + +int rand_read_cpu(RAND_poll_fn cb, void *arg) +{ + char buff[RANDOMNESS_NEEDED]; + + /* If RDSEED is available, use that. */ + if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) { + if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) { + cb(arg, buff, (int)sizeof(buff), sizeof(buff)); + return 1; + } + } + + /* Second choice is RDRAND. */ + if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) { + if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) { + cb(arg, buff, (int)sizeof(buff), sizeof(buff)); + return 1; + } + } + + return 0; +} +#endif + + +/* + * DRBG has two sets of callbacks; we only discuss the "entropy" one + * here. When the DRBG needs additional randomness bits (called entropy + * in the NIST document), it calls the get_entropy callback which fills in + * a pointer and returns the number of bytes. When the DRBG is finished with + * the buffer, it calls the cleanup_entropy callback, with the value of + * the buffer that the get_entropy callback filled in. + * + * Get entropy from the system, via RAND_poll if needed. The |entropy| + * is the bits of randomness required, and is expected to fit into a buffer + * of |min_len|..|max__len| size. We assume we're getting high-quality + * randomness from the system, and that |min_len| bytes will do. + */ +size_t drbg_entropy_from_system(RAND_DRBG *drbg, + unsigned char **pout, + int entropy, size_t min_len, size_t max_len) +{ + int i; + + + if (min_len > (size_t)drbg->size) { + /* Should not happen. See comment near RANDOMNESS_NEEDED. */ + min_len = drbg->size; + } + + if (drbg->filled) { + /* Re-use what we have. */ + *pout = drbg->randomness; + return drbg->size; + } + + drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size) + : OPENSSL_malloc(drbg->size); + + /* If we don't have enough, try to get more. */ + CRYPTO_THREAD_write_lock(rand_bytes.lock); + for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) { + CRYPTO_THREAD_unlock(rand_bytes.lock); + RAND_poll(); + CRYPTO_THREAD_write_lock(rand_bytes.lock); + } + + /* Get desired amount, but no more than we have. */ + if (min_len > rand_bytes.curr) + min_len = rand_bytes.curr; + if (min_len != 0) { + memcpy(drbg->randomness, rand_bytes.buff, min_len); + drbg->filled = 1; + /* Update amount left and shift it down. */ + rand_bytes.curr -= min_len; + if (rand_bytes.curr != 0) + memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr); + } + CRYPTO_THREAD_unlock(rand_bytes.lock); + *pout = drbg->randomness; + return min_len; +} + +size_t drbg_entropy_from_parent(RAND_DRBG *drbg, + unsigned char **pout, + int entropy, size_t min_len, size_t max_len) +{ + int st; + + if (min_len > (size_t)drbg->size) { + /* Should not happen. See comment near RANDOMNESS_NEEDED. */ + min_len = drbg->size; + } + + drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size) + : OPENSSL_malloc(drbg->size); + + /* Get random from parent, include our state as additional input. */ + st = RAND_DRBG_generate(drbg->parent, drbg->randomness, min_len, 0, + (unsigned char *)drbg, sizeof(*drbg)); + if (st == 0) + return 0; + drbg->filled = 1; + *pout = drbg->randomness; + return min_len; +} + +void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out) +{ + drbg->filled = 0; + if (drbg->secure) + OPENSSL_secure_clear_free(drbg->randomness, drbg->size); + else + OPENSSL_clear_free(drbg->randomness, drbg->size); + drbg->randomness = NULL; +} + + +/* + * Set up a global DRBG. + */ +static int setup_drbg(RAND_DRBG *drbg) +{ + int ret = 1; + + drbg->lock = CRYPTO_THREAD_lock_new(); + ret &= drbg->lock != NULL; + drbg->size = RANDOMNESS_NEEDED; + drbg->secure = CRYPTO_secure_malloc_initialized(); + drbg->randomness = NULL; + /* If you change these parameters, see RANDOMNESS_NEEDED */ + ret &= RAND_DRBG_set(drbg, + NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1; + ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system, + drbg_release_entropy, NULL, NULL) == 1; + return ret; +} + +static void free_drbg(RAND_DRBG *drbg) +{ + CRYPTO_THREAD_lock_free(drbg->lock); + RAND_DRBG_uninstantiate(drbg); +} + +void rand_fork() +{ + rand_fork_count++; +} DEFINE_RUN_ONCE_STATIC(do_rand_init) { int ret = 1; + #ifndef OPENSSL_NO_ENGINE rand_engine_lock = CRYPTO_THREAD_lock_new(); ret &= rand_engine_lock != NULL; #endif rand_meth_lock = CRYPTO_THREAD_lock_new(); ret &= rand_meth_lock != NULL; + + rand_bytes.lock = CRYPTO_THREAD_lock_new(); + ret &= rand_bytes.lock != NULL; + rand_bytes.curr = 0; + rand_bytes.size = MAX_RANDOMNESS_HELD; + rand_bytes.secure = CRYPTO_secure_malloc_initialized(); + rand_bytes.buff = rand_bytes.secure + ? OPENSSL_secure_malloc(rand_bytes.size) + : OPENSSL_malloc(rand_bytes.size); + ret &= rand_bytes.buff != NULL; + ret &= setup_drbg(&rand_drbg); + ret &= setup_drbg(&priv_drbg); return ret; } @@ -49,7 +247,27 @@ void rand_cleanup_int(void) CRYPTO_THREAD_lock_free(rand_engine_lock); #endif CRYPTO_THREAD_lock_free(rand_meth_lock); - rand_drbg_cleanup(); + CRYPTO_THREAD_lock_free(rand_bytes.lock); + if (rand_bytes.secure) + OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size); + else + OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size); + free_drbg(&rand_drbg); + free_drbg(&priv_drbg); +} + +/* + * RAND_poll_ex() gets a function pointer to call when it has random bytes. + * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add(). + */ +static void call_rand_add(void* arg, const void *buf, int num, double r) +{ + RAND_add(buf, num, r); +} + +int RAND_poll(void) +{ + return RAND_poll_ex(call_rand_add, NULL); } int RAND_set_rand_method(const RAND_METHOD *meth) @@ -86,10 +304,10 @@ const RAND_METHOD *RAND_get_rand_method(void) default_RAND_meth = tmp_meth; } else { ENGINE_finish(e); - default_RAND_meth = &openssl_rand_meth; + default_RAND_meth = &rand_meth; } #else - default_RAND_meth = &openssl_rand_meth; + default_RAND_meth = &rand_meth; #endif } tmp_meth = default_RAND_meth; @@ -139,6 +357,25 @@ void RAND_add(const void *buf, int num, double randomness) meth->add(buf, num, randomness); } +/* + * This function is not part of RAND_METHOD, so if we're not using + * the default method, then just call RAND_bytes(). Otherwise make + * sure we're instantiated and use the private DRBG. + */ +int RAND_priv_bytes(unsigned char *buf, int num) +{ + const RAND_METHOD *meth = RAND_get_rand_method(); + + if (meth != RAND_OpenSSL()) + return RAND_bytes(buf, num); + + if (priv_drbg.state == DRBG_UNINITIALISED + && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0) + return 0; + return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0); + +} + int RAND_bytes(unsigned char *buf, int num) { const RAND_METHOD *meth = RAND_get_rand_method();