/* * Copyright 2011-2020 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 #include #include #include #include "rand_local.h" #include "internal/thread_once.h" #include "crypto/rand.h" #include "crypto/cryptlib.h" /* * Support framework for NIST SP 800-90A DRBG * * See manual page RAND_DRBG(7) for a general overview. * * The OpenSSL model is to have new and free functions, and that new * does all initialization. That is not the NIST model, which has * instantiation and un-instantiate, and re-use within a new/free * lifecycle. (No doubt this comes from the desire to support hardware * DRBG, where allocation of resources on something like an HSM is * a much bigger deal than just re-setting an allocated resource.) */ /* * The three shared DRBG instances * * There are three shared DRBG instances: , , and . */ /* * The DRBG * * Not used directly by the application, only for reseeding the two other * DRBGs. It reseeds itself by pulling either randomness from os entropy * sources or by consuming randomness which was added by RAND_add(). * * The DRBG is a global instance which is accessed concurrently by * all threads. The necessary locking is managed automatically by its child * DRBG instances during reseeding. */ static RAND_DRBG *master_drbg; /* * The DRBG * * Used by default for generating random bytes using RAND_bytes(). * * The DRBG is thread-local, i.e., there is one instance per thread. */ static CRYPTO_THREAD_LOCAL public_drbg; /* * The DRBG * * Used by default for generating private keys using RAND_priv_bytes() * * The DRBG is thread-local, i.e., there is one instance per thread. */ static CRYPTO_THREAD_LOCAL private_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"; static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT; static int rand_drbg_type = RAND_DRBG_TYPE; static unsigned int rand_drbg_flags = RAND_DRBG_FLAGS; static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL; static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL; static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL; static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL; /* A logical OR of all used DRBG flag bits (currently there is only one) */ static const unsigned int rand_drbg_used_flags = RAND_DRBG_FLAG_CTR_NO_DF; static RAND_DRBG *drbg_setup(RAND_DRBG *parent); static RAND_DRBG *rand_drbg_new(int secure, int type, unsigned int flags, RAND_DRBG *parent); /* * Set/initialize |drbg| to be of type |type|, with optional |flags|. * * If |type| and |flags| are zero, use the defaults * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags) { int ret = 1; if (type == 0 && flags == 0) { type = rand_drbg_type; flags = rand_drbg_flags; } /* If set is called multiple times - clear the old one */ if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) { drbg->meth->uninstantiate(drbg); rand_pool_free(drbg->adin_pool); drbg->adin_pool = NULL; } drbg->state = DRBG_UNINITIALISED; drbg->flags = flags; drbg->type = type; switch (type) { default: drbg->type = 0; drbg->flags = 0; drbg->meth = NULL; RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE); return 0; case 0: /* Uninitialized; that's okay. */ drbg->meth = NULL; return 1; case NID_aes_128_ctr: case NID_aes_192_ctr: case NID_aes_256_ctr: ret = drbg_ctr_init(drbg); break; case NID_sha1: case NID_sha224: case NID_sha256: case NID_sha384: case NID_sha512: case NID_sha512_224: case NID_sha512_256: #ifndef OPENSSL_NO_SM3 case NID_sm3: #endif ret = drbg_hash_init(drbg); break; } if (ret == 0) { drbg->state = DRBG_ERROR; RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG); } return ret; } /* * Set/initialize default |type| and |flag| for new drbg instances. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set_defaults(int type, unsigned int flags) { int ret = 1; switch (type) { default: RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE); return 0; case NID_aes_128_ctr: case NID_aes_192_ctr: case NID_aes_256_ctr: case NID_sha1: case NID_sha224: case NID_sha256: case NID_sha384: case NID_sha512: case NID_sha512_224: case NID_sha512_256: #ifndef OPENSSL_NO_SM3 case NID_sm3: #endif break; } if ((flags & ~rand_drbg_used_flags) != 0) { RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS); return 0; } rand_drbg_type = type; rand_drbg_flags = flags; return ret; } /* * Allocate memory and initialize a new DRBG. The DRBG is allocated on * the secure heap if |secure| is nonzero and the secure heap is enabled. * The |parent|, if not NULL, will be used as random source for reseeding. * * Returns a pointer to the new DRBG instance on success, NULL on failure. */ static RAND_DRBG *rand_drbg_new(int secure, int type, unsigned int flags, RAND_DRBG *parent) { RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg)); if (drbg == NULL) { RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE); return NULL; } drbg->secure = secure && CRYPTO_secure_allocated(drbg); drbg->fork_id = openssl_get_fork_id(); drbg->parent = parent; if (parent == NULL) { drbg->get_entropy = rand_drbg_get_entropy; drbg->cleanup_entropy = rand_drbg_cleanup_entropy; #ifndef RAND_DRBG_GET_RANDOM_NONCE drbg->get_nonce = rand_drbg_get_nonce; drbg->cleanup_nonce = rand_drbg_cleanup_nonce; #endif drbg->reseed_interval = master_reseed_interval; drbg->reseed_time_interval = master_reseed_time_interval; } else { drbg->get_entropy = rand_drbg_get_entropy; drbg->cleanup_entropy = rand_drbg_cleanup_entropy; /* * Do not provide nonce callbacks, the child DRBGs will * obtain their nonce using random bits from the parent. */ drbg->reseed_interval = slave_reseed_interval; drbg->reseed_time_interval = slave_reseed_time_interval; } if (RAND_DRBG_set(drbg, type, flags) == 0) goto err; if (parent != NULL) { rand_drbg_lock(parent); if (drbg->strength > parent->strength) { /* * We currently don't support the algorithm from NIST SP 800-90C * 10.1.2 to use a weaker DRBG as source */ rand_drbg_unlock(parent); RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK); goto err; } rand_drbg_unlock(parent); } return drbg; err: RAND_DRBG_free(drbg); return NULL; } RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent) { return rand_drbg_new(0, type, flags, parent); } RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent) { return rand_drbg_new(1, type, flags, parent); } /* * Uninstantiate |drbg| and free all memory. */ void RAND_DRBG_free(RAND_DRBG *drbg) { if (drbg == NULL) return; if (drbg->meth != NULL) drbg->meth->uninstantiate(drbg); rand_pool_free(drbg->adin_pool); CRYPTO_THREAD_lock_free(drbg->lock); CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data); if (drbg->secure) OPENSSL_secure_clear_free(drbg, sizeof(*drbg)); else OPENSSL_clear_free(drbg, sizeof(*drbg)); } /* * Instantiate |drbg|, after it has been initialized. Use |pers| and * |perslen| as prediction-resistance input. * * Requires that drbg->lock is already locked for write, if non-null. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_instantiate(RAND_DRBG *drbg, const unsigned char *pers, size_t perslen) { unsigned char *nonce = NULL, *entropy = NULL; size_t noncelen = 0, entropylen = 0; size_t min_entropy = drbg->strength; size_t min_entropylen = drbg->min_entropylen; size_t max_entropylen = drbg->max_entropylen; if (perslen > drbg->max_perslen) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_PERSONALISATION_STRING_TOO_LONG); goto end; } if (drbg->meth == NULL) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); goto end; } if (drbg->state != DRBG_UNINITIALISED) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE : RAND_R_ALREADY_INSTANTIATED); goto end; } drbg->state = DRBG_ERROR; /* * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy * and nonce in 1 call by increasing the entropy with 50% and increasing * the minimum length to accommodate the length of the nonce. * We do this in case a nonce is require and get_nonce is NULL. */ if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) { min_entropy += drbg->strength / 2; min_entropylen += drbg->min_noncelen; max_entropylen += drbg->max_noncelen; } drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter); if (drbg->reseed_next_counter) { drbg->reseed_next_counter++; if(!drbg->reseed_next_counter) drbg->reseed_next_counter = 1; } if (drbg->get_entropy != NULL) entropylen = drbg->get_entropy(drbg, &entropy, min_entropy, min_entropylen, max_entropylen, 0); if (entropylen < min_entropylen || entropylen > max_entropylen) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY); goto end; } if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) { 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); goto end; } } if (!drbg->meth->instantiate(drbg, entropy, entropylen, nonce, noncelen, pers, perslen)) { RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG); goto end; } drbg->state = DRBG_READY; drbg->reseed_gen_counter = 1; drbg->reseed_time = time(NULL); tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter); end: if (entropy != NULL && drbg->cleanup_entropy != NULL) drbg->cleanup_entropy(drbg, entropy, entropylen); if (nonce != NULL && drbg->cleanup_nonce != NULL) drbg->cleanup_nonce(drbg, nonce, noncelen); if (drbg->state == DRBG_READY) return 1; return 0; } /* * Uninstantiate |drbg|. Must be instantiated before it can be used. * * Requires that drbg->lock is already locked for write, if non-null. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_uninstantiate(RAND_DRBG *drbg) { if (drbg->meth == NULL) { drbg->state = DRBG_ERROR; RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE, RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); return 0; } /* Clear the entire drbg->ctr struct, then reset some important * members of the drbg->ctr struct (e.g. keysize, df_ks) to their * initial values. */ drbg->meth->uninstantiate(drbg); return RAND_DRBG_set(drbg, drbg->type, drbg->flags); } /* * Reseed |drbg|, mixing in the specified data * * Requires that drbg->lock is already locked for write, if non-null. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_reseed(RAND_DRBG *drbg, const unsigned char *adin, size_t adinlen, int prediction_resistance) { unsigned char *entropy = NULL; size_t entropylen = 0; if (drbg->state == DRBG_ERROR) { RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE); return 0; } if (drbg->state == DRBG_UNINITIALISED) { RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED); return 0; } if (adin == NULL) { adinlen = 0; } else if (adinlen > drbg->max_adinlen) { RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG); return 0; } drbg->state = DRBG_ERROR; drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter); if (drbg->reseed_next_counter) { drbg->reseed_next_counter++; if(!drbg->reseed_next_counter) drbg->reseed_next_counter = 1; } if (drbg->get_entropy != NULL) entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, drbg->min_entropylen, drbg->max_entropylen, prediction_resistance); if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) { RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY); goto end; } if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen)) goto end; drbg->state = DRBG_READY; drbg->reseed_gen_counter = 1; drbg->reseed_time = time(NULL); tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter); end: if (entropy != NULL && drbg->cleanup_entropy != NULL) drbg->cleanup_entropy(drbg, entropy, entropylen); if (drbg->state == DRBG_READY) return 1; return 0; } /* * 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->seed_pool != NULL) { RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); drbg->state = DRBG_ERROR; rand_pool_free(drbg->seed_pool); drbg->seed_pool = NULL; return 0; } if (buffer != NULL) { if (entropy > 0) { if (drbg->max_entropylen < len) { RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_INPUT_TOO_LONG); drbg->state = DRBG_ERROR; return 0; } if (entropy > 8 * len) { RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE); drbg->state = DRBG_ERROR; return 0; } /* will be picked up by the rand_drbg_get_entropy() callback */ drbg->seed_pool = rand_pool_attach(buffer, len, entropy); if (drbg->seed_pool == NULL) return 0; } else { if (drbg->max_adinlen < len) { RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ADDITIONAL_INPUT_TOO_LONG); drbg->state = DRBG_ERROR; 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) { /* reinstantiate drbg */ RAND_DRBG_instantiate(drbg, (const unsigned char *) ossl_pers_string, sizeof(ossl_pers_string) - 1); /* 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. */ drbg->meth->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, 0); } } rand_pool_free(drbg->seed_pool); drbg->seed_pool = NULL; 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|. * * Requires that drbg->lock is already locked for write, if non-null. * * 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) { int fork_id; int reseed_required = 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; } if (adinlen > drbg->max_adinlen) { RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG); return 0; } fork_id = openssl_get_fork_id(); if (drbg->fork_id != fork_id) { drbg->fork_id = fork_id; reseed_required = 1; } if (drbg->reseed_interval > 0) { if (drbg->reseed_gen_counter >= drbg->reseed_interval) reseed_required = 1; } if (drbg->reseed_time_interval > 0) { time_t now = time(NULL); if (now < drbg->reseed_time || now - drbg->reseed_time >= drbg->reseed_time_interval) reseed_required = 1; } if (drbg->parent != NULL) { unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter); if (reseed_counter > 0 && tsan_load(&drbg->parent->reseed_prop_counter) != reseed_counter) reseed_required = 1; } if (reseed_required || prediction_resistance) { if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) { RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR); return 0; } adin = NULL; adinlen = 0; } if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) { drbg->state = DRBG_ERROR; RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR); return 0; } drbg->reseed_gen_counter++; return 1; } /* * Generates |outlen| random bytes and stores them in |out|. It will * using the given |drbg| to generate the bytes. * * Requires that drbg->lock is already locked for write, if non-null. * * Returns 1 on success 0 on failure. */ int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen) { unsigned char *additional = NULL; size_t additional_len; size_t chunk; size_t ret = 0; if (drbg->adin_pool == NULL) { if (drbg->type == 0) goto err; drbg->adin_pool = rand_pool_new(0, 0, 0, drbg->max_adinlen); if (drbg->adin_pool == NULL) goto err; } additional_len = rand_drbg_get_additional_data(drbg->adin_pool, &additional); for ( ; outlen > 0; outlen -= chunk, out += chunk) { chunk = outlen; if (chunk > drbg->max_request) chunk = drbg->max_request; ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len); if (!ret) goto err; } ret = 1; err: if (additional != NULL) rand_drbg_cleanup_additional_data(drbg->adin_pool, additional); return ret; } /* * Set the RAND_DRBG callbacks for obtaining entropy and nonce. * * Setting the callbacks is allowed only if the drbg has not been * initialized yet. Otherwise, the operation will fail. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set_callbacks(RAND_DRBG *drbg, 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 || drbg->parent != NULL) return 0; drbg->get_entropy = get_entropy; drbg->cleanup_entropy = cleanup_entropy; drbg->get_nonce = get_nonce; drbg->cleanup_nonce = cleanup_nonce; return 1; } /* * Set the reseed interval. * * The drbg will reseed automatically whenever the number of generate * requests exceeds the given reseed interval. If the reseed interval * is 0, then this feature is disabled. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval) { if (interval > MAX_RESEED_INTERVAL) return 0; drbg->reseed_interval = interval; return 1; } /* * Set the reseed time interval. * * The drbg will reseed automatically whenever the time elapsed since * the last reseeding exceeds the given reseed time interval. For safety, * a reseeding will also occur if the clock has been reset to a smaller * value. * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval) { if (interval > MAX_RESEED_TIME_INTERVAL) return 0; drbg->reseed_time_interval = interval; return 1; } /* * Set the default values for reseed (time) intervals of new DRBG instances * * The default values can be set independently for master DRBG instances * (without a parent) and slave DRBG instances (with parent). * * Returns 1 on success, 0 on failure. */ int RAND_DRBG_set_reseed_defaults( unsigned int _master_reseed_interval, unsigned int _slave_reseed_interval, time_t _master_reseed_time_interval, time_t _slave_reseed_time_interval ) { if (_master_reseed_interval > MAX_RESEED_INTERVAL || _slave_reseed_interval > MAX_RESEED_INTERVAL) return 0; if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL) return 0; master_reseed_interval = _master_reseed_interval; slave_reseed_interval = _slave_reseed_interval; master_reseed_time_interval = _master_reseed_time_interval; slave_reseed_time_interval = _slave_reseed_time_interval; return 1; } /* * Locks the given drbg. Locking a drbg which does not have locking * enabled is considered a successful no-op. * * Returns 1 on success, 0 on failure. */ int rand_drbg_lock(RAND_DRBG *drbg) { if (drbg->lock != NULL) return CRYPTO_THREAD_write_lock(drbg->lock); return 1; } /* * Unlocks the given drbg. Unlocking a drbg which does not have locking * enabled is considered a successful no-op. * * Returns 1 on success, 0 on failure. */ int rand_drbg_unlock(RAND_DRBG *drbg) { if (drbg->lock != NULL) return CRYPTO_THREAD_unlock(drbg->lock); return 1; } /* * Enables locking for the given drbg * * Locking can only be enabled if the random generator * is in the uninitialized state. * * Returns 1 on success, 0 on failure. */ int rand_drbg_enable_locking(RAND_DRBG *drbg) { if (drbg->state != DRBG_UNINITIALISED) { RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, RAND_R_DRBG_ALREADY_INITIALIZED); return 0; } if (drbg->lock == NULL) { if (drbg->parent != NULL && drbg->parent->lock == NULL) { RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, RAND_R_PARENT_LOCKING_NOT_ENABLED); return 0; } drbg->lock = CRYPTO_THREAD_lock_new(); if (drbg->lock == NULL) { RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, RAND_R_FAILED_TO_CREATE_LOCK); return 0; } } return 1; } /* * Get and set the EXDATA */ int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg) { return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg); } void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx) { return CRYPTO_get_ex_data(&drbg->ex_data, idx); } /* * The following functions provide a RAND_METHOD that works on the * global DRBG. They lock. */ /* * Allocates a new global DRBG on the secure heap (if enabled) and * initializes it with default settings. * * Returns a pointer to the new DRBG instance on success, NULL on failure. */ static RAND_DRBG *drbg_setup(RAND_DRBG *parent) { RAND_DRBG *drbg; drbg = RAND_DRBG_secure_new(rand_drbg_type, rand_drbg_flags, parent); if (drbg == NULL) return NULL; /* Only the master DRBG needs to have a lock */ if (parent == NULL && rand_drbg_enable_locking(drbg) == 0) goto err; /* enable seed propagation */ tsan_store(&drbg->reseed_prop_counter, 1); /* * Ignore instantiation error to support just-in-time instantiation. * * The state of the drbg will be checked in RAND_DRBG_generate() and * an automatic recovery is attempted. */ (void)RAND_DRBG_instantiate(drbg, (const unsigned char *) ossl_pers_string, sizeof(ossl_pers_string) - 1); return drbg; err: RAND_DRBG_free(drbg); return NULL; } /* * Initialize the global DRBGs on first use. * Returns 1 on success, 0 on failure. */ DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init) { /* * ensure that libcrypto is initialized, otherwise the * DRBG locks are not cleaned up properly */ if (!OPENSSL_init_crypto(0, NULL)) return 0; if (!CRYPTO_THREAD_init_local(&private_drbg, NULL)) return 0; if (!CRYPTO_THREAD_init_local(&public_drbg, NULL)) goto err1; master_drbg = drbg_setup(NULL); if (master_drbg == NULL) goto err2; return 1; err2: CRYPTO_THREAD_cleanup_local(&public_drbg); err1: CRYPTO_THREAD_cleanup_local(&private_drbg); return 0; } /* Clean up the global DRBGs before exit */ void rand_drbg_cleanup_int(void) { if (master_drbg != NULL) { RAND_DRBG_free(master_drbg); master_drbg = NULL; CRYPTO_THREAD_cleanup_local(&private_drbg); CRYPTO_THREAD_cleanup_local(&public_drbg); } } void drbg_delete_thread_state(void) { RAND_DRBG *drbg; drbg = CRYPTO_THREAD_get_local(&public_drbg); CRYPTO_THREAD_set_local(&public_drbg, NULL); RAND_DRBG_free(drbg); drbg = CRYPTO_THREAD_get_local(&private_drbg); CRYPTO_THREAD_set_local(&private_drbg, NULL); RAND_DRBG_free(drbg); } /* Implements the default OpenSSL RAND_bytes() method */ static int drbg_bytes(unsigned char *out, int count) { int ret; RAND_DRBG *drbg = RAND_DRBG_get0_public(); if (drbg == NULL) return 0; ret = RAND_DRBG_bytes(drbg, out, count); return ret; } /* * Calculates the minimum length of a full entropy buffer * which is necessary to seed (i.e. instantiate) the DRBG * successfully. */ size_t rand_drbg_seedlen(RAND_DRBG *drbg) { /* * If no os entropy source is available then RAND_seed(buffer, bufsize) * is expected to succeed if and only if the buffer length satisfies * the following requirements, which follow from the calculations * in RAND_DRBG_instantiate(). */ size_t min_entropy = drbg->strength; size_t min_entropylen = drbg->min_entropylen; /* * Extra entropy for the random nonce in the absence of a * get_nonce callback, see comment in RAND_DRBG_instantiate(). */ if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) { min_entropy += drbg->strength / 2; min_entropylen += drbg->min_noncelen; } /* * Convert entropy requirement from bits to bytes * (dividing by 8 without rounding upwards, because * all entropy requirements are divisible by 8). */ min_entropy >>= 3; /* Return a value that satisfies both requirements */ return min_entropy > min_entropylen ? min_entropy : min_entropylen; } /* Implements the default OpenSSL RAND_add() method */ static int drbg_add(const void *buf, int num, double randomness) { int ret = 0; RAND_DRBG *drbg = RAND_DRBG_get0_master(); size_t buflen; size_t seedlen; if (drbg == NULL) return 0; if (num < 0 || randomness < 0.0) return 0; rand_drbg_lock(drbg); seedlen = rand_drbg_seedlen(drbg); buflen = (size_t)num; if (buflen < seedlen || randomness < (double) seedlen) { #if defined(OPENSSL_RAND_SEED_NONE) /* * If no os entropy source is available, a reseeding will fail * inevitably. So we use a trick to mix the buffer contents into * the DRBG state without forcing a reseeding: we generate a * dummy random byte, using the buffer content as additional data. * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF. */ unsigned char dummy[1]; ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen); rand_drbg_unlock(drbg); return ret; #else /* * If an os entropy source is available then we declare the buffer content * as additional data by setting randomness to zero and trigger a regular * reseeding. */ randomness = 0.0; #endif } if (randomness > (double)seedlen) { /* * 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. Note that randomness is measured in bytes, * not bits, so this value corresponds to eight times the * security strength. */ randomness = (double)seedlen; } ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness)); rand_drbg_unlock(drbg); 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; RAND_DRBG *drbg = RAND_DRBG_get0_master(); if (drbg == NULL) return 0; rand_drbg_lock(drbg); ret = drbg->state == DRBG_READY ? 1 : 0; rand_drbg_unlock(drbg); return ret; } /* * Get the master DRBG. * Returns pointer to the DRBG on success, NULL on failure. * */ RAND_DRBG *RAND_DRBG_get0_master(void) { if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) return NULL; return master_drbg; } /* * Get the public DRBG. * Returns pointer to the DRBG on success, NULL on failure. */ RAND_DRBG *RAND_DRBG_get0_public(void) { RAND_DRBG *drbg; if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) return NULL; drbg = CRYPTO_THREAD_get_local(&public_drbg); if (drbg == NULL) { if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND)) return NULL; drbg = drbg_setup(master_drbg); CRYPTO_THREAD_set_local(&public_drbg, drbg); } return drbg; } /* * Get the private DRBG. * Returns pointer to the DRBG on success, NULL on failure. */ RAND_DRBG *RAND_DRBG_get0_private(void) { RAND_DRBG *drbg; if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) return NULL; drbg = CRYPTO_THREAD_get_local(&private_drbg); if (drbg == NULL) { if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND)) return NULL; drbg = drbg_setup(master_drbg); CRYPTO_THREAD_set_local(&private_drbg, drbg); } return drbg; } RAND_METHOD rand_meth = { drbg_seed, drbg_bytes, NULL, drbg_add, drbg_bytes, drbg_status }; RAND_METHOD *RAND_OpenSSL(void) { return &rand_meth; }