diff options
Diffstat (limited to 'crypto/rand')
| -rw-r--r-- | crypto/rand/drbg_lib.c | 311 | ||||
| -rw-r--r-- | crypto/rand/drbg_rand.c | 4 | ||||
| -rw-r--r-- | crypto/rand/rand_err.c | 21 | ||||
| -rw-r--r-- | crypto/rand/rand_lcl.h | 87 | ||||
| -rw-r--r-- | crypto/rand/rand_lib.c | 520 | ||||
| -rw-r--r-- | crypto/rand/rand_unix.c | 127 | ||||
| -rw-r--r-- | crypto/rand/rand_vms.c | 13 | ||||
| -rw-r--r-- | crypto/rand/rand_win.c | 84 |
8 files changed, 864 insertions, 303 deletions
diff --git a/crypto/rand/drbg_lib.c b/crypto/rand/drbg_lib.c index b7f7e4c341..eef5e11cc5 100644 --- a/crypto/rand/drbg_lib.c +++ b/crypto/rand/drbg_lib.c @@ -18,6 +18,9 @@ static RAND_DRBG rand_drbg; /* The default global DRBG. */ static RAND_DRBG priv_drbg; /* The global private-key DRBG. */ +/* NIST SP 800-90A DRBG recommends the use of a personalization string. */ +static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG"; + /* * Support framework for NIST SP 800-90A DRBG, AES-CTR mode. * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG. @@ -30,7 +33,9 @@ static RAND_DRBG priv_drbg; /* The global private-key DRBG. */ * a much bigger deal than just re-setting an allocated resource.) */ -static CRYPTO_ONCE rand_init_drbg = CRYPTO_ONCE_STATIC_INIT; +static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT; + +static int drbg_setup(RAND_DRBG *drbg, const char *name); /* * Set/initialize |drbg| to be of type |nid|, with optional |flags|. @@ -76,15 +81,14 @@ RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent) RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE); goto err; } - drbg->size = RANDOMNESS_NEEDED; drbg->fork_count = rand_fork_count; drbg->parent = parent; if (RAND_DRBG_set(drbg, type, flags) < 0) goto err; if (parent != NULL) { - if (!RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_parent, - drbg_release_entropy, + if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy, + rand_drbg_cleanup_entropy, NULL, NULL)) goto err; } @@ -101,8 +105,7 @@ err: */ void RAND_DRBG_free(RAND_DRBG *drbg) { - /* The global DRBG is free'd by rand_cleanup_drbg_int() */ - if (drbg == NULL || drbg == &rand_drbg) + if (drbg == NULL) return; ctr_uninstantiate(drbg); @@ -136,7 +139,8 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg, if (drbg->get_entropy != NULL) entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, drbg->min_entropylen, drbg->max_entropylen); - if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) { + if (entropylen < drbg->min_entropylen + || entropylen > drbg->max_entropylen) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY); goto end; } @@ -145,7 +149,8 @@ int RAND_DRBG_instantiate(RAND_DRBG *drbg, noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2, drbg->min_noncelen, drbg->max_noncelen); if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) { - RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE); + RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, + RAND_R_ERROR_RETRIEVING_NONCE); goto end; } } @@ -164,6 +169,15 @@ end: drbg->cleanup_entropy(drbg, entropy, entropylen); if (nonce != NULL && drbg->cleanup_nonce!= NULL ) drbg->cleanup_nonce(drbg, nonce, noncelen); + if (drbg->pool != NULL) { + if (drbg->state == DRBG_READY) { + RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, + RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED); + drbg->state = DRBG_ERROR; + } + RAND_POOL_free(drbg->pool); + drbg->pool = NULL; + } if (drbg->state == DRBG_READY) return 1; return 0; @@ -182,7 +196,7 @@ int RAND_DRBG_uninstantiate(RAND_DRBG *drbg) } /* - * Mix in the specified data to reseed |drbg|. + * Reseed |drbg|, mixing in the specified data */ int RAND_DRBG_reseed(RAND_DRBG *drbg, const unsigned char *adin, size_t adinlen) @@ -210,7 +224,8 @@ int RAND_DRBG_reseed(RAND_DRBG *drbg, if (drbg->get_entropy != NULL) entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, drbg->min_entropylen, drbg->max_entropylen); - if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) { + if (entropylen < drbg->min_entropylen + || entropylen > drbg->max_entropylen) { RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY); goto end; } @@ -229,22 +244,132 @@ end: } /* + * Restart |drbg|, using the specified entropy or additional input + * + * Tries its best to get the drbg instantiated by all means, + * regardless of its current state. + * + * Optionally, a |buffer| of |len| random bytes can be passed, + * which is assumed to contain at least |entropy| bits of entropy. + * + * If |entropy| > 0, the buffer content is used as entropy input. + * + * If |entropy| == 0, the buffer content is used as additional input + * + * Returns 1 on success, 0 on failure. + * + * This function is used internally only. + */ +int rand_drbg_restart(RAND_DRBG *drbg, + const unsigned char *buffer, size_t len, size_t entropy) +{ + int reseeded = 0; + const unsigned char *adin = NULL; + size_t adinlen = 0; + + if (drbg->pool != NULL) { + RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); + RAND_POOL_free(drbg->pool); + drbg->pool = NULL; + } + + if (buffer != NULL) { + if (entropy > 0) { + if (drbg->max_entropylen < len) { + RANDerr(RAND_F_RAND_DRBG_RESTART, + RAND_R_ENTROPY_INPUT_TOO_LONG); + return 0; + } + + if (entropy > 8 * len) { + RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE); + return 0; + } + + /* will be picked up by the rand_drbg_get_entropy() callback */ + drbg->pool = RAND_POOL_new(entropy, len, len); + if (drbg->pool == NULL) + return 0; + + RAND_POOL_add(drbg->pool, buffer, len, entropy); + } else { + if (drbg->max_adinlen < len) { + RANDerr(RAND_F_RAND_DRBG_RESTART, + RAND_R_ADDITIONAL_INPUT_TOO_LONG); + return 0; + } + adin = buffer; + adinlen = len; + } + } + + /* repair error state */ + if (drbg->state == DRBG_ERROR) + RAND_DRBG_uninstantiate(drbg); + + /* repair uninitialized state */ + if (drbg->state == DRBG_UNINITIALISED) { + drbg_setup(drbg, NULL); + /* already reseeded. prevent second reseeding below */ + reseeded = (drbg->state == DRBG_READY); + } + + /* refresh current state if entropy or additional input has been provided */ + if (drbg->state == DRBG_READY) { + if (adin != NULL) { + /* + * mix in additional input without reseeding + * + * Similar to RAND_DRBG_reseed(), but the provided additional + * data |adin| is mixed into the current state without pulling + * entropy from the trusted entropy source using get_entropy(). + * This is not a reseeding in the strict sense of NIST SP 800-90A. + */ + ctr_reseed(drbg, adin, adinlen, NULL, 0); + } else if (reseeded == 0) { + /* do a full reseeding if it has not been done yet above */ + RAND_DRBG_reseed(drbg, NULL, 0); + } + } + + /* check whether a given entropy pool was cleared properly during reseed */ + if (drbg->pool != NULL) { + drbg->state = DRBG_ERROR; + RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); + RAND_POOL_free(drbg->pool); + drbg->pool = NULL; + return 0; + } + + return drbg->state == DRBG_READY; +} + +/* * Generate |outlen| bytes into the buffer at |out|. Reseed if we need * to or if |prediction_resistance| is set. Additional input can be * sent in |adin| and |adinlen|. + * + * Returns 1 on success, 0 on failure. + * */ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen, int prediction_resistance, const unsigned char *adin, size_t adinlen) { - if (drbg->state == DRBG_ERROR) { - RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE); - return 0; - } - if (drbg->state == DRBG_UNINITIALISED) { - RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED); - return 0; + if (drbg->state != DRBG_READY) { + /* try to recover from previous errors */ + rand_drbg_restart(drbg, NULL, 0, 0); + + if (drbg->state == DRBG_ERROR) { + RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE); + return 0; + } + if (drbg->state == DRBG_UNINITIALISED) { + RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED); + return 0; + } } + if (outlen > drbg->max_request) { RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG); return 0; @@ -285,21 +410,55 @@ int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen, } /* - * Set the callbacks for entropy and nonce. We currently don't use - * the nonce; that's mainly for the KATs + * Set the RAND_DRBG callbacks for obtaining entropy and nonce. + * + * In the following, the signature and the semantics of the + * get_entropy() and cleanup_entropy() callbacks are explained. + * + * GET_ENTROPY + * + * size_t get_entropy(RAND_DRBG *ctx, + * unsigned char **pout, + * int entropy, + * size_t min_len, size_t max_len); + * + * This is a request to allocate and fill a buffer of size + * |min_len| <= size <= |max_len| (in bytes) which contains + * at least |entropy| bits of randomness. The buffer's address is + * to be returned in |*pout| and the number of collected + * randomness bytes (which may be less than the allocated size + * of the buffer) as return value. + * + * If the callback fails to acquire at least |entropy| bits of + * randomness, it shall return a buffer length of 0. + * + * CLEANUP_ENTROPY + * + * void cleanup_entropy(RAND_DRBG *ctx, + * unsigned char *out, size_t outlen); + * + * A request to clear and free the buffer allocated by get_entropy(). + * The values |out| and |outlen| are expected to be the random buffer's + * address and length, as returned by the get_entropy() callback. + * + * GET_NONCE, CLEANUP_NONCE + * + * Signature and semantics of the get_nonce() and cleanup_nonce() + * callbacks are analogous to get_entropy() and cleanup_entropy(). + * Currently, the nonce is used only for the known answer tests. */ int RAND_DRBG_set_callbacks(RAND_DRBG *drbg, - RAND_DRBG_get_entropy_fn cb_get_entropy, - RAND_DRBG_cleanup_entropy_fn cb_cleanup_entropy, - RAND_DRBG_get_nonce_fn cb_get_nonce, - RAND_DRBG_cleanup_nonce_fn cb_cleanup_nonce) + RAND_DRBG_get_entropy_fn get_entropy, + RAND_DRBG_cleanup_entropy_fn cleanup_entropy, + RAND_DRBG_get_nonce_fn get_nonce, + RAND_DRBG_cleanup_nonce_fn cleanup_nonce) { if (drbg->state != DRBG_UNINITIALISED) return 0; - drbg->get_entropy = cb_get_entropy; - drbg->cleanup_entropy = cb_cleanup_entropy; - drbg->get_nonce = cb_get_nonce; - drbg->cleanup_nonce = cb_cleanup_nonce; + drbg->get_entropy = get_entropy; + drbg->cleanup_entropy = cleanup_entropy; + drbg->get_nonce = get_nonce; + drbg->cleanup_nonce = cleanup_nonce; return 1; } @@ -334,23 +493,40 @@ void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx) */ /* - * Creates a global DRBG with default settings. + * Initializes the DRBG with default settings. + * For global DRBGs a global lock is created with the given name * Returns 1 on success, 0 on failure */ -static int setup_drbg(RAND_DRBG *drbg, const char *name) +static int drbg_setup(RAND_DRBG *drbg, const char *name) { int ret = 1; - drbg->lock = CRYPTO_THREAD_glock_new(name); - ret &= drbg->lock != NULL; - drbg->size = RANDOMNESS_NEEDED; - drbg->secure = CRYPTO_secure_malloc_initialized(); - /* If you change these parameters, see RANDOMNESS_NEEDED */ + if (name != NULL) { + if (drbg->lock != NULL) { + RANDerr(RAND_F_DRBG_SETUP, ERR_R_INTERNAL_ERROR); + return 0; + } + + drbg->lock = CRYPTO_THREAD_glock_new(name); + if (drbg->lock == NULL) { + RANDerr(RAND_F_DRBG_SETUP, RAND_R_FAILED_TO_CREATE_LOCK); + return 0; + } + } + 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; - ret &= RAND_DRBG_instantiate(drbg, NULL, 0) == 1; + RAND_DRBG_NID, RAND_DRBG_FLAG_CTR_USE_DF) == 1; + ret &= RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy, + rand_drbg_cleanup_entropy, NULL, NULL) == 1; + /* + * Ignore instantiation error so support just-in-time instantiation. + * + * The state of the drbg will be checked in RAND_DRBG_generate() and + * an automatic recovery is attempted. + */ + RAND_DRBG_instantiate(drbg, + (const unsigned char *) ossl_pers_string, + sizeof(ossl_pers_string) - 1); return ret; } @@ -358,30 +534,31 @@ static int setup_drbg(RAND_DRBG *drbg, const char *name) * Initialize the global DRBGs on first use. * Returns 1 on success, 0 on failure. */ -DEFINE_RUN_ONCE_STATIC(do_rand_init_drbg) +DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init) { int ret = 1; - ret &= setup_drbg(&rand_drbg, "rand_drbg"); - ret &= setup_drbg(&priv_drbg, "priv_drbg"); + ret &= drbg_setup(&rand_drbg, "rand_drbg"); + ret &= drbg_setup(&priv_drbg, "priv_drbg"); return ret; } -/* Clean up a DRBG and free it */ -static void free_drbg(RAND_DRBG *drbg) +/* Cleans up the given global DRBG */ +static void drbg_cleanup(RAND_DRBG *drbg) { CRYPTO_THREAD_lock_free(drbg->lock); RAND_DRBG_uninstantiate(drbg); } /* Clean up the global DRBGs before exit */ -void rand_cleanup_drbg_int(void) +void rand_drbg_cleanup_int(void) { - free_drbg(&rand_drbg); - free_drbg(&priv_drbg); + drbg_cleanup(&rand_drbg); + drbg_cleanup(&priv_drbg); } +/* Implements the default OpenSSL RAND_bytes() method */ static int drbg_bytes(unsigned char *out, int count) { int ret = 0; @@ -410,34 +587,44 @@ err: return ret; } +/* Implements the default OpenSSL RAND_add() method */ static int drbg_add(const void *buf, int num, double randomness) { - unsigned char *in = (unsigned char *)buf; - unsigned char *out, *end; + int ret = 0; + RAND_DRBG *drbg = RAND_DRBG_get0_global(); - CRYPTO_THREAD_write_lock(rand_bytes.lock); - out = &rand_bytes.buff[rand_bytes.curr]; - end = &rand_bytes.buff[rand_bytes.size]; + if (drbg == NULL) + return 0; - /* Copy whatever fits into the end of the buffer. */ - for ( ; --num >= 0 && out < end; rand_bytes.curr++) - *out++ = *in++; + if (num < 0 || randomness < 0.0) + return 0; - /* XOR any the leftover. */ - while (num > 0) { - for (out = rand_bytes.buff; --num >= 0 && out < end; ) - *out++ ^= *in++; + if (randomness > (double)drbg->max_entropylen) { + /* + * The purpose of this check is to bound |randomness| by a + * relatively small value in order to prevent an integer + * overflow when multiplying by 8 in the rand_drbg_restart() + * call below. + */ + return 0; } - CRYPTO_THREAD_unlock(rand_bytes.lock); - return 1; + CRYPTO_THREAD_write_lock(drbg->lock); + ret = rand_drbg_restart(drbg, buf, + (size_t)(unsigned int)num, + (size_t)(8*randomness)); + CRYPTO_THREAD_unlock(drbg->lock); + + return ret; } +/* Implements the default OpenSSL RAND_seed() method */ static int drbg_seed(const void *buf, int num) { return drbg_add(buf, num, num); } +/* Implements the default OpenSSL RAND_status() method */ static int drbg_status(void) { int ret; @@ -458,7 +645,7 @@ static int drbg_status(void) */ RAND_DRBG *RAND_DRBG_get0_global(void) { - if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg)) + if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) return NULL; return &rand_drbg; @@ -470,7 +657,7 @@ RAND_DRBG *RAND_DRBG_get0_global(void) */ RAND_DRBG *RAND_DRBG_get0_priv_global(void) { - if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg)) + if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) return NULL; return &priv_drbg; diff --git a/crypto/rand/drbg_rand.c b/crypto/rand/drbg_rand.c index 83f1ad876f..f45ef1424c 100644 --- a/crypto/rand/drbg_rand.c +++ b/crypto/rand/drbg_rand.c @@ -341,9 +341,9 @@ int ctr_init(RAND_DRBG *drbg) AES_set_encrypt_key(df_key, drbg->strength, &ctr->df_ks); drbg->min_entropylen = ctr->keylen; - drbg->max_entropylen = DRBG_MAX_LENGTH; + drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen; drbg->min_noncelen = drbg->min_entropylen / 2; - drbg->max_noncelen = DRBG_MAX_LENGTH; + drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen; drbg->max_perslen = DRBG_MAX_LENGTH; drbg->max_adinlen = DRBG_MAX_LENGTH; } else { diff --git a/crypto/rand/rand_err.c b/crypto/rand/rand_err.c index 707f010e4c..dc6140c075 100644 --- a/crypto/rand/rand_err.c +++ b/crypto/rand/rand_err.c @@ -16,6 +16,7 @@ static const ERR_STRING_DATA RAND_str_functs[] = { {ERR_PACK(ERR_LIB_RAND, RAND_F_DRBG_BYTES, 0), "drbg_bytes"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_DRBG_GET_ENTROPY, 0), "drbg_get_entropy"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_DRBG_SETUP, 0), "drbg_setup"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_GET_ENTROPY, 0), "get_entropy"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_BYTES, 0), "RAND_bytes"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_GENERATE, 0), @@ -24,8 +25,16 @@ static const ERR_STRING_DATA RAND_str_functs[] = { "RAND_DRBG_instantiate"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_NEW, 0), "RAND_DRBG_new"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_RESEED, 0), "RAND_DRBG_reseed"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_RESTART, 0), "rand_drbg_restart"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_DRBG_SET, 0), "RAND_DRBG_set"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_LOAD_FILE, 0), "RAND_load_file"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ADD, 0), "RAND_POOL_add"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ADD_BEGIN, 0), + "RAND_POOL_add_begin"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ADD_END, 0), "RAND_POOL_add_end"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_BYTES_NEEDED, 0), + "RAND_POOL_bytes_needed"}, + {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_NEW, 0), "RAND_POOL_new"}, {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_WRITE_FILE, 0), "RAND_write_file"}, {0, NULL} }; @@ -35,9 +44,17 @@ static const ERR_STRING_DATA RAND_str_reasons[] = { "additional input too long"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ALREADY_INSTANTIATED), "already instantiated"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ARGUMENT_OUT_OF_RANGE), + "argument out of range"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_CANNOT_OPEN_FILE), "Cannot open file"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_DRBG_NOT_INITIALISED), "drbg not initialised"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ENTROPY_INPUT_TOO_LONG), + "entropy input too long"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ENTROPY_OUT_OF_RANGE), + "entropy out of range"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED), + "error entropy pool was ignored"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ERROR_INITIALISING_DRBG), "error initialising drbg"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ERROR_INSTANTIATING_DRBG), @@ -48,6 +65,8 @@ static const ERR_STRING_DATA RAND_str_reasons[] = { "error retrieving entropy"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_ERROR_RETRIEVING_NONCE), "error retrieving nonce"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_FAILED_TO_CREATE_LOCK), + "failed to create lock"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_FUNC_NOT_IMPLEMENTED), "Function not implemented"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_FWRITE_ERROR), "Error writing file"}, @@ -60,6 +79,8 @@ static const ERR_STRING_DATA RAND_str_reasons[] = { {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PERSONALISATION_STRING_TOO_LONG), "personalisation string too long"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_PRNG_NOT_SEEDED), "PRNG not seeded"}, + {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_RANDOM_POOL_OVERFLOW), + "random pool overflow"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG), "request too large for drbg"}, {ERR_PACK(ERR_LIB_RAND, 0, RAND_R_RESEED_ERROR), "reseed error"}, diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h index 498b7e687e..10a6f00a2d 100644 --- a/crypto/rand/rand_lcl.h +++ b/crypto/rand/rand_lcl.h @@ -17,28 +17,24 @@ # include <openssl/ec.h> # include "internal/rand.h" -/* - * Amount of randomness (in bytes) we want for initial seeding. - * This is based on the fact that we use AES-128 as the CRBG, and - * that we use the derivation function. If either of those changes, - * (see rand_init() in rand_lib.c), change this. - */ -# define RANDOMNESS_NEEDED 16 - /* How many times to read the TSC as a randomness source. */ # define TSC_READ_COUNT 4 -/* Maximum amount of randomness to hold in RAND_BYTES_BUFFER. */ -# define MAX_RANDOMNESS_HELD (4 * RANDOMNESS_NEEDED) - /* Maximum count allowed in reseeding */ # define MAX_RESEED (1 << 24) -/* How often we call RAND_poll() in drbg_entropy_from_system */ -# define RAND_POLL_RETRIES 8 +/* Max size of additional input and personalization string. */ +# define DRBG_MAX_LENGTH 4096 -/* Max size of entropy, addin, etc. Larger than any reasonable value */ -# define DRBG_MAX_LENGTH 0x7ffffff0 +/* + * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len + * + * The current factor is large enough that the RAND_POOL can store a + * random input which has a lousy entropy rate of 0.0625 bits per byte. + * This input will be sent through the derivation function which 'compresses' + * the low quality input into a high quality output. + */ +# define DRBG_MINMAX_FACTOR 128 /* DRBG status values */ @@ -51,22 +47,6 @@ typedef enum drbg_status_e { /* - * A buffer of random bytes to be fed as "entropy" into the DRBG. RAND_add() - * adds data to the buffer, and the drbg_entropy_from_system() pulls data from - * the buffer. We have a separate data structure because of the way the - * API is defined; otherwise we'd run into deadlocks (RAND_bytes -> - * RAND_DRBG_generate* -> drbg_entropy_from_system -> RAND_poll -> RAND_add -> - * drbg_add*; the functions with an asterisk lock). - */ -typedef struct rand_bytes_buffer_st { - CRYPTO_RWLOCK *lock; - unsigned char *buff; - size_t size; - size_t curr; - int secure; -} RAND_BYTES_BUFFER; - -/* * The state of a DRBG AES-CTR. */ typedef struct rand_drbg_ctr_st { @@ -94,30 +74,34 @@ struct rand_drbg_st { int nid; /* the underlying algorithm */ int fork_count; unsigned short flags; /* various external flags */ - char secure; + /* - * This is a fixed-size buffer, but we malloc to make it a little - * harder to find; a classic security/performance trade-off. + * The random pool is used by RAND_add()/drbg_add() to attach random + * data to the global drbg, such that the rand_drbg_get_entropy() callback + * can pull it during instantiation and reseeding. This is necessary to + * reconcile the different philosophies of the RAND and the RAND_DRBG + * with respect to how randomness is added to the RNG during reseeding + * (see PR #4328). */ - int size; + RAND_POOL *pool; - /* + /* * The following parameters are setup by the per-type "init" function. * * Currently the only type is CTR_DRBG, its init function is ctr_init(). * - * The parameters are closely related to the ones described in + * The parameters are closely related to the ones described in * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one * crucial difference: In the NIST standard, all counts are given - * in bits, whereas in OpenSSL entropy counts are given in bits + * in bits, whereas in OpenSSL entropy counts are given in bits * and buffer lengths are given in bytes. - * + * * Since this difference has lead to some confusion in the past, * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055]) - * the 'len' suffix has been added to all buffer sizes for + * the 'len' suffix has been added to all buffer sizes for * clarification. */ - + int strength; size_t max_request; size_t min_entropylen, max_entropylen; @@ -143,23 +127,24 @@ struct rand_drbg_st { /* The global RAND method, and the global buffer and DRBG instance. */ extern RAND_METHOD rand_meth; -extern RAND_BYTES_BUFFER rand_bytes; /* How often we've forked (only incremented in child). */ extern int rand_fork_count; /* Hardware-based seeding functions. */ -void rand_read_tsc(RAND_poll_cb rand_add, void *arg); -int rand_read_cpu(RAND_poll_cb rand_add, void *arg); +size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool); +size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool); /* DRBG entropy callbacks. */ -void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out, size_t outlen); -size_t drbg_entropy_from_parent(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len); -size_t drbg_entropy_from_system(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len); +size_t rand_drbg_get_entropy(RAND_DRBG *drbg, + unsigned char **pout, + int entropy, size_t min_len, size_t max_len); +void rand_drbg_cleanup_entropy(RAND_DRBG *drbg, + unsigned char *out, size_t outlen); + +/* DRBG helpers */ +int rand_drbg_restart(RAND_DRBG *drbg, + const unsigned char *buffer, size_t len, size_t entropy); /* DRBG functions implementing AES-CTR */ int ctr_init(RAND_DRBG *drbg); diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c index 2f2ab6a86d..6f8deca1f9 100644 --- a/crypto/rand/rand_lib.c +++ b/crypto/rand/rand_lib.c @@ -24,7 +24,7 @@ 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 @@ -37,12 +37,15 @@ int rand_fork_count; # error "RDTSC enabled? Should not be possible!" /* + * Acquire entropy from high-speed clock + * * 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. + * high-speed clock, it can help. + * + * Returns the total entropy count, if it exceeds the requested + * entropy count. Otherwise, returns an entropy count of 0. */ -void rand_read_tsc(RAND_poll_cb rand_add, void *arg) +size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool) { unsigned char c; int i; @@ -50,126 +53,141 @@ void rand_read_tsc(RAND_poll_cb rand_add, void *arg) if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) { for (i = 0; i < TSC_READ_COUNT; i++) { c = (unsigned char)(OPENSSL_rdtsc() & 0xFF); - rand_add(arg, &c, 1, 0.5); + RAND_POOL_add(pool, &c, 1, 4); } } + return RAND_POOL_entropy_available(pool); } #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); +size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len); +size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len); extern unsigned int OPENSSL_ia32cap_P[]; -int rand_read_cpu(RAND_poll_cb rand_add, void *arg) +/* + * Acquire entropy using Intel-specific cpu instructions + * + * Uses the RDSEED instruction if available, otherwise uses + * RDRAND if available. + * + * For the differences between RDSEED and RDRAND, and why RDSEED + * is the preferred choice, see https://goo.gl/oK3KcN + * + * Returns the total entropy count, if it exceeds the requested + * entropy count. Otherwise, returns an entropy count of 0. + */ +size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool) { - 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)) { - rand_add(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)) { - rand_add(arg, buff, (int)sizeof(buff), sizeof(buff)); - return 1; + size_t bytes_needed; + unsigned char *buffer; + + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + if (bytes_needed > 0) { + buffer = RAND_POOL_add_begin(pool, bytes_needed); + + if (buffer != NULL) { + + /* If RDSEED is available, use that. */ + if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) { + if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed) + == bytes_needed) + return RAND_POOL_add_end(pool, + bytes_needed, + 8 * bytes_needed); + } + + /* Second choice is RDRAND. */ + if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) { + if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed) + == bytes_needed) + return RAND_POOL_add_end(pool, + bytes_needed, + 8 * bytes_needed); + } + + return RAND_POOL_add_end(pool, 0, 0); } } - return 0; + return RAND_POOL_entropy_available(pool); } #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. + * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks()) + * + * If the DRBG has a parent, then the required amount of entropy input + * is fetched using the parent's RAND_DRBG_generate(). * - * 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. + * Otherwise, the entropy is polled from the system entropy sources + * using RAND_POOL_acquire_entropy(). + * + * If a random pool has been added to the DRBG using RAND_add(), then + * its entropy will be used up first. */ -size_t drbg_entropy_from_system(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len) +size_t rand_drbg_get_entropy(RAND_DRBG *drbg, + unsigned char **pout, + int entropy, size_t min_len, size_t max_len) { - int i; - unsigned char *randomness; + size_t ret = 0; + size_t entropy_available = 0; + RAND_POOL *pool = RAND_POOL_new(entropy, min_len, max_len); - if (min_len > (size_t)drbg->size) { - /* Should not happen. See comment near RANDOMNESS_NEEDED. */ - min_len = drbg->size; + if (pool == NULL) + return 0; + + if (drbg->pool) { + RAND_POOL_add(pool, + RAND_POOL_buffer(drbg->pool), + RAND_POOL_length(drbg->pool), + RAND_POOL_entropy(drbg->pool)); + RAND_POOL_free(drbg->pool); + drbg->pool = NULL; } - randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size) - : OPENSSL_malloc(drbg->size); + if (drbg->parent) { + size_t bytes_needed = RAND_POOL_bytes_needed(pool, 8); + unsigned char *buffer = RAND_POOL_add_begin(pool, bytes_needed); - /* 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); - } + if (buffer != NULL) { + size_t bytes = 0; - /* 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(randomness, rand_bytes.buff, min_len); - /* 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 = randomness; - return min_len; -} + /* Get entropy from parent, include our state as additional input */ + if (RAND_DRBG_generate(drbg->parent, + buffer, bytes_needed, + 0, + (unsigned char *)drbg, sizeof(*drbg)) != 0) + bytes = bytes_needed; -size_t drbg_entropy_from_parent(RAND_DRBG *drbg, - unsigned char **pout, - int entropy, size_t min_len, size_t max_len) -{ - int st; - unsigned char *randomness; + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); + } - if (min_len > (size_t)drbg->size) { - /* Should not happen. See comment near RANDOMNESS_NEEDED. */ - min_len = drbg->size; + } else { + /* Get entropy by polling system entropy sources. */ + entropy_available = RAND_POOL_acquire_entropy(pool); } - 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, randomness, min_len, 0, - (unsigned char *)drbg, sizeof(*drbg)); - if (st == 0) { - drbg_release_entropy(drbg, randomness, min_len); - return 0; + if (entropy_available > 0) { + ret = RAND_POOL_length(pool); + *pout = RAND_POOL_detach(pool); } - *pout = randomness; - return min_len; + + RAND_POOL_free(pool); + return ret; } -void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out, size_t outlen) + +/* + * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks()) + * + */ +void rand_drbg_cleanup_entropy(RAND_DRBG *drbg, + unsigned char *out, size_t outlen) { - if (drbg->secure) - OPENSSL_secure_clear_free(out, outlen); - else - OPENSSL_clear_free(out, outlen); + OPENSSL_secure_clear_free(out, outlen); } void rand_fork() @@ -188,15 +206,6 @@ DEFINE_RUN_ONCE_STATIC(do_rand_init) rand_meth_lock = CRYPTO_THREAD_glock_new("rand_meth"); ret &= rand_meth_lock != NULL; - rand_bytes.lock = CRYPTO_THREAD_glock_new("rand_bytes"); - 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; return ret; } @@ -211,25 +220,314 @@ void rand_cleanup_int(void) CRYPTO_THREAD_lock_free(rand_engine_lock); #endif CRYPTO_THREAD_lock_free(rand_meth_lock); - 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); } /* - * 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(). + * RAND_poll() reseeds the default RNG using random input + * + * The random input is obtained from polling various entropy + * sources which depend on the operating system and are + * configurable via the --with-rand-seed configure option. */ -static void call_rand_add(void* arg, const void *buf, int num, double r) +int RAND_poll(void) { - RAND_add(buf, num, r); + int ret = 0; + + RAND_POOL *pool = NULL; + + const RAND_METHOD *meth = RAND_get_rand_method(); + + if (meth == RAND_OpenSSL()) { + /* fill random pool and seed the default DRBG */ + RAND_DRBG *drbg = RAND_DRBG_get0_global(); + + if (drbg == NULL) + return 0; + + CRYPTO_THREAD_write_lock(drbg->lock); + ret = rand_drbg_restart(drbg, NULL, 0, 0); + CRYPTO_THREAD_unlock(drbg->lock); + + return ret; + + } else { + /* fill random pool and seed the current legacy RNG */ + pool = RAND_POOL_new(RAND_DRBG_STRENGTH, + RAND_DRBG_STRENGTH / 8, + DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8)); + if (pool == NULL) + return 0; + + if (RAND_POOL_acquire_entropy(pool) == 0) + goto err; + + if (meth->add == NULL + || meth->add(RAND_POOL_buffer(pool), + RAND_POOL_length(pool), + (RAND_POOL_entropy(pool) / 8.0)) == 0) + goto err; + + ret = 1; + } + +err: + RAND_POOL_free(pool); + return ret; } -int RAND_poll(void) +/* + * The 'random pool' acts as a dumb container for collecting random + * input from various entropy sources. The pool has no knowledge about + * whether its randomness is fed into a legacy RAND_METHOD via RAND_add() + * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the + * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and + * 4) cleanup the random pool again. + * + * The random pool contains no locking mechanism because its scope and + * lifetime is intended to be restricted to a single stack frame. + */ +struct rand_pool_st { + unsigned char *buffer; /* points to the beginning of the random pool */ + size_t len; /* current number of random bytes contained in the pool */ + + size_t min_len; /* minimum number of random bytes requested */ + size_t max_len; /* maximum number of random bytes (allocated buffer size) */ + size_t entropy; /* current entropy count in bits */ + size_t requested_entropy; /* requested entropy count in bits */ +}; + +/* + * Allocate memory and initialize a new random pool + */ + +RAND_POOL *RAND_POOL_new(int entropy, size_t min_len, size_t max_len) +{ + RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool)); + + if (pool == NULL) { + RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE); + goto err; + } + + pool->min_len = min_len; + pool->max_len = max_len; + + pool->buffer = OPENSSL_secure_zalloc(pool->max_len); + if (pool->buffer == NULL) { + RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE); + goto err; + } + + pool->requested_entropy = entropy; + + return pool; + +err: + OPENSSL_free(pool); + return NULL; +} + +/* + * Free |pool|, securely erasing its buffer. + */ +void RAND_POOL_free(RAND_POOL *pool) { - return RAND_poll_ex(call_rand_add, NULL); + if (pool == NULL) + return; + + OPENSSL_secure_clear_free(pool->buffer, pool->max_len); + OPENSSL_free(pool); +} + +/* + * Return the |pool|'s buffer to the caller (readonly). + */ +const unsigned char *RAND_POOL_buffer(RAND_POOL *pool) +{ + return pool->buffer; +} + +/* + * Return the |pool|'s entropy to the caller. + */ +size_t RAND_POOL_entropy(RAND_POOL *pool) +{ + return pool->entropy; +} + +/* + * Return the |pool|'s buffer length to the caller. + */ +size_t RAND_POOL_length(RAND_POOL *pool) +{ + return pool->len; +} + +/* + * Detach the |pool| buffer and return it to the caller. + * It's the responsibility of the caller to free the buffer + * using OPENSSL_secure_clear_free(). + */ +unsigned char *RAND_POOL_detach(RAND_POOL *pool) +{ + unsigned char *ret = pool->buffer; + pool->buffer = NULL; + return ret; +} + + +/* + * If every byte of the input contains |entropy_per_bytes| bits of entropy, + * how many bytes does one need to obtain at least |bits| bits of entropy? + */ +#define ENTROPY_TO_BYTES(bits, entropy_per_bytes) \ + (((bits) + ((entropy_per_bytes) - 1))/(entropy_per_bytes)) + + +/* + * Checks whether the |pool|'s entropy is available to the caller. + * This is the case when entropy count and buffer length are high enough. + * Returns + * + * |entropy| if the entropy count and buffer size is large enough + * 0 otherwise + */ +size_t RAND_POOL_entropy_available(RAND_POOL *pool) +{ + if (pool->entropy < pool->requested_entropy) + return 0; + + if (pool->len < pool->min_len) + return 0; + + return pool->entropy; +} + +/* + * Returns the (remaining) amount of entropy needed to fill + * the random pool. + */ + +size_t RAND_POOL_entropy_needed(RAND_POOL *pool) +{ + if (pool->entropy < pool->requested_entropy) + return pool->requested_entropy - pool->entropy; + + return 0; +} + +/* + * Returns the number of bytes needed to fill the pool, assuming + * the input has 'entropy_per_byte' entropy bits per byte. + * In case of an error, 0 is returned. + */ + +size_t RAND_POOL_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte) +{ + size_t bytes_needed; + size_t entropy_needed = RAND_POOL_entropy_needed(pool); + + if (entropy_per_byte < 1 || entropy_per_byte > 8) { + RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE); + return 0; + } + + bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_per_byte); + + if (bytes_needed > pool->max_len - pool->len) { + /* not enough space left */ + RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW); + return 0; + } + + if (pool->len < pool->min_len && + bytes_needed < pool->min_len - pool->len) + /* to meet the min_len requirement */ + bytes_needed = pool->min_len - pool->len; + + return bytes_needed; +} + +/* Returns the remaining number of bytes available */ +size_t RAND_POOL_bytes_remaining(RAND_POOL *pool) +{ + return pool->max_len - pool->len; +} + +/* + * Add random bytes to the random pool. + * + * It is expected that the |buffer| contains |len| bytes of + * random input which contains at least |entropy| bits of + * randomness. + * + * Return available amount of entropy after this operation. + * (see RAND_POOL_entropy_available(pool)) + */ +size_t RAND_POOL_add(RAND_POOL *pool, + const unsigned char *buffer, size_t len, size_t entropy) +{ + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG); + return 0; + } + + if (len > 0) { + memcpy(pool->buffer + pool->len, buffer, len); + pool->len += len; + pool->entropy += entropy; + } + + return RAND_POOL_entropy_available(pool); +} + +/* + * Start to add random bytes to the random pool in-place. + * + * Reserves the next |len| bytes for adding random bytes in-place + * and returns a pointer to the buffer. + * The caller is allowed to copy up to |len| bytes into the buffer. + * If |len| == 0 this is considered a no-op and a NULL pointer + * is returned without producing an error message. + * + * After updating the buffer, RAND_POOL_add_end() needs to be called + * to finish the udpate operation (see next comment). + */ +unsigned char *RAND_POOL_add_begin(RAND_POOL *pool, size_t len) +{ + if (len == 0) + return NULL; + + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW); + return NULL; + } + + return pool->buffer + pool->len; +} + +/* + * Finish to add random bytes to the random pool in-place. + * + * Finishes an in-place update of the random pool started by + * RAND_POOL_add_begin() (see previous comment). + * It is expected that |len| bytes of random input have been added + * to the buffer which contain at least |entropy| bits of randomness. + * It is allowed to add less bytes than originally reserved. + */ +size_t RAND_POOL_add_end(RAND_POOL *pool, size_t len, size_t entropy) +{ + if (len > pool->max_len - pool->len) { + RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW); + return 0; + } + + if (len > 0) { + pool->len += len; + pool->entropy += entropy; + } + + return RAND_POOL_entropy_available(pool); } int RAND_set_rand_method(const RAND_METHOD *meth) diff --git a/crypto/rand/rand_unix.c b/crypto/rand/rand_unix.c index 08ea55fbb9..f5a59cb28a 100644 --- a/crypto/rand/rand_unix.c +++ b/crypto/rand/rand_unix.c @@ -14,12 +14,18 @@ #include "rand_lcl.h" #include <stdio.h> -#if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) +#ifdef OPENSSL_RAND_SEED_GETRANDOM +# include <linux/random.h> +#endif -# if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \ +#if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \ !defined(OPENSSL_RAND_SEED_NONE) -# error "UEFI and VXWorks only support seeding NONE" -# endif +# error "UEFI and VXWorks only support seeding NONE" +#endif + +#if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) \ + || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \ + || defined(OPENSSL_SYS_UEFI)) # if defined(OPENSSL_SYS_VOS) @@ -46,16 +52,16 @@ * would be far more predictable. This should only be used for legacy * platforms. * - * As a precaution, we generate four times the required amount of seed - * data. + * As a precaution, we assume only 2 bits of entropy per byte. */ -int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) +size_t RAND_POOL_acquire_entropy(RAND_POOL *pool) { short int code; gid_t curr_gid; pid_t curr_pid; uid_t curr_uid; int i, k; + size_t bytes_needed; struct timespec ts; unsigned char v; # ifdef OPENSSL_SYS_VOS_HPPA @@ -71,13 +77,15 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) * different processes. */ curr_gid = getgid(); - rand_add(arg, &curr_gid, sizeof curr_gid, 0); + RAND_POOL_add(pool, &curr_gid, sizeof(curr_gid), 0); curr_pid = getpid(); - rand_add(arg, &curr_pid, sizeof curr_pid, 0); + RAND_POOL_add(pool, &curr_pid, sizeof(curr_pid), 0); curr_uid = getuid(); - rand_add(arg, &curr_uid, sizeof curr_uid, 0); + RAND_POOL_add(pool, &curr_uid, sizeof(curr_uid), 0); - for (i = 0; i < (RANDOMNESS_NEEDED * 4); i++) { + bytes_needed = RAND_POOL_bytes_needed(pool, 2 /*entropy_per_byte*/); + + for (i = 0; i < bytes_needed; i++) { /* * burn some cpu; hope for interrupts, cache collisions, bus * interference, etc. @@ -98,9 +106,9 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) /* Get wall clock time, take 8 bits. */ clock_gettime(CLOCK_REALTIME, &ts); v = (unsigned char)(ts.tv_nsec & 0xFF); - rand_add(arg, &v, sizeof v, 1); + RAND_POOL_add(pool, arg, &v, sizeof(v) , 2); } - return 1; + return RAND_POOL_entropy_available(pool); } # else @@ -127,27 +135,44 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) # endif /* - * Try the various seeding methods in turn, exit when succesful. + * Try the various seeding methods in turn, exit when successful. + * + * TODO(DRBG): If more than one entropy source is available, is it + * preferable to stop as soon as enough entropy has been collected + * (as favored by @rsalz) or should one rather be defensive and add + * more entropy than requested and/or from different sources? + * + * Currently, the user can select multiple entropy sources in the + * configure step, yet in practice only the first available source + * will be used. A more flexible solution has been requested, but + * currently it is not clear how this can be achieved without + * overengineering the problem. There are many parameters which + * could be taken into account when selecting the order and amount + * of input from the different entropy sources (trust, quality, + * possibility of blocking). */ -int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) +size_t RAND_POOL_acquire_entropy(RAND_POOL *pool) { # ifdef OPENSSL_RAND_SEED_NONE - return 0; + return RAND_POOL_entropy_available(pool); # else - int ok = 1; - char temp[RANDOMNESS_NEEDED]; -# define TEMPSIZE (int)sizeof(temp) + size_t bytes_needed; + size_t entropy_available = 0; + unsigned char *buffer; # ifdef OPENSSL_RAND_SEED_GETRANDOM - { - int i = getrandom(temp, TEMPSIZE, 0); + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; - if (i >= 0) { - rand_add(arg, temp, i, i); - if (i == TEMPSIZE) - goto done; - } + if (getrandom(buffer, bytes_needed, 0) == (int)bytes_needed) + bytes = bytes_needed; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; # endif # if defined(OPENSSL_RAND_SEED_LIBRANDOM) @@ -157,7 +182,8 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) # endif # ifdef OPENSSL_RAND_SEED_DEVRANDOM - { + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + if (bytes_needed > 0) { static const char *paths[] = { DEVRANDOM, NULL }; FILE *fp; int i; @@ -166,44 +192,59 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) if ((fp = fopen(paths[i], "rb")) == NULL) continue; setbuf(fp, NULL); - if (fread(temp, 1, TEMPSIZE, fp) == TEMPSIZE) { - rand_add(arg, temp, TEMPSIZE, TEMPSIZE); - fclose(fp); - goto done; + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + if (fread(buffer, 1, bytes_needed, fp) == bytes_needed) + bytes = bytes_needed; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } fclose(fp); + if (entropy_available > 0) + return entropy_available; + + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); } } # endif # ifdef OPENSSL_RAND_SEED_RDTSC - rand_read_tsc(rand_add, arg); + entropy_available = rand_acquire_entropy_from_tsc(pool); + if (entropy_available > 0) + return entropy_available; # endif # ifdef OPENSSL_RAND_SEED_RDCPU - if (rand_read_cpu(rand_add, arg)) - goto done; + entropy_available = rand_acquire_entropy_from_cpu(pool); + if (entropy_available > 0) + return entropy_available; # endif # ifdef OPENSSL_RAND_SEED_EGD - { + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + if (bytes_needed > 0) { static const char *paths[] = { DEVRANDOM_EGD, NULL }; int i; for (i = 0; paths[i] != NULL; i++) { - if (RAND_query_egd_bytes(paths[i], temp, TEMPSIZE) == TEMPSIZE) { - rand_add(arg, temp, TEMPSIZE, TEMPSIZE); - goto done; + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + int num = RAND_query_egd_bytes(paths[i], + buffer, (int)bytes_needed); + if (num == (int)bytes_needed) + bytes = bytes_needed; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; } } # endif - ok = 0; - -done: - OPENSSL_cleanse(temp, TEMPSIZE); - return ok; + return RAND_POOL_entropy_available(pool); # endif } # endif diff --git a/crypto/rand/rand_vms.c b/crypto/rand/rand_vms.c index 773373d1a6..4ec4b35bd4 100644 --- a/crypto/rand/rand_vms.c +++ b/crypto/rand/rand_vms.c @@ -54,7 +54,7 @@ static struct items_data_st { {0, 0} }; -int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) +size_t RAND_POOL_acquire_entropy(RAND_POOL *pool) { /* determine the number of items in the JPI array */ struct items_data_st item_entry; @@ -112,9 +112,14 @@ int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) total_length += (tmp_length - 1); - /* size of seed is total_length*4 bytes (64bytes) */ - rand_add(arg, (PTR_T)data_buffer, total_length * 4, total_length * 2); - return 1; + /* + * Size of seed is total_length*4 bytes (64bytes). The original assumption + * was that it contains 4 bits of entropy per byte. This makes a total + * amount of total_length*16 bits (256bits). + */ + return RAND_POOL_add(pool, + (PTR_T)data_buffer, total_length * 4, + total_length * 16); } #endif diff --git a/crypto/rand/rand_win.c b/crypto/rand/rand_win.c index 8637ca4185..9eff319bc8 100644 --- a/crypto/rand/rand_win.c +++ b/crypto/rand/rand_win.c @@ -10,7 +10,6 @@ #include "internal/cryptlib.h" #include <openssl/rand.h> #include "rand_lcl.h" - #if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) # ifndef OPENSSL_RAND_SEED_OS @@ -39,55 +38,80 @@ # define INTEL_DEF_PROV L"Intel Hardware Cryptographic Service Provider" # endif -int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) +size_t RAND_POOL_acquire_entropy(RAND_POOL *pool) { # ifndef USE_BCRYPTGENRANDOM HCRYPTPROV hProvider; - int ok = 0; # endif - BYTE buf[RANDOMNESS_NEEDED]; + unsigned char *buffer; + size_t bytes_needed; + size_t entropy_available = 0; + # ifdef OPENSSL_RAND_SEED_RDTSC - rand_read_tsc(cb, arg); + entropy_available = rand_acquire_entropy_from_tsc(pool); + if (entropy_available > 0) + return entropy_available; # endif + # ifdef OPENSSL_RAND_SEED_RDCPU - if (rand_read_cpu(cb, arg)) - return 1; + entropy_available = rand_acquire_entropy_from_cpu(pool); + if (entropy_available > 0) + return entropy_available; # endif # ifdef USE_BCRYPTGENRANDOM - if (BCryptGenRandom(NULL, buf, (ULONG)sizeof(buf), - BCRYPT_USE_SYSTEM_PREFERRED_RNG) == STATUS_SUCCESS) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - return 1; + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + if (BCryptGenRandom(NULL, buffer, bytes_needed, + BCRYPT_USE_SYSTEM_PREFERRED_RNG) == STATUS_SUCCESS) + bytes = bytes_needed; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; # else - /* poll the CryptoAPI PRNG */ - if (CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL, - CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { - if (CryptGenRandom(hProvider, (DWORD)sizeof(buf), buf) != 0) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - ok = 1; + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + /* poll the CryptoAPI PRNG */ + if (CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL, + CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { + if (CryptGenRandom(hProvider, bytes_needed, buffer) != 0) + bytes = bytes_needed; + + CryptReleaseContext(hProvider, 0); } - CryptReleaseContext(hProvider, 0); - if (ok) - return 1; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; + + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + /* poll the Pentium PRG with CryptoAPI */ + if (CryptAcquireContextW(&hProvider, NULL, + INTEL_DEF_PROV, PROV_INTEL_SEC, + CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { + if (CryptGenRandom(hProvider, bytes_needed, buffer) != 0) + bytes = bytes_needed; - /* poll the Pentium PRG with CryptoAPI */ - if (CryptAcquireContextW(&hProvider, NULL, INTEL_DEF_PROV, PROV_INTEL_SEC, - CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { - if (CryptGenRandom(hProvider, (DWORD)sizeof(buf), buf) != 0) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - ok = 1; + CryptReleaseContext(hProvider, 0); } - CryptReleaseContext(hProvider, 0); - if (ok) - return 1; + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; # endif - return 0; + return RAND_POOL_entropy_available(pool); } # if OPENSSL_API_COMPAT < 0x10100000L |