diff options
Diffstat (limited to 'deps/openssl/openssl/crypto/rand/drbg_lib.c')
| -rw-r--r-- | deps/openssl/openssl/crypto/rand/drbg_lib.c | 1159 |
1 files changed, 1159 insertions, 0 deletions
diff --git a/deps/openssl/openssl/crypto/rand/drbg_lib.c b/deps/openssl/openssl/crypto/rand/drbg_lib.c new file mode 100644 index 0000000000..a13282181d --- /dev/null +++ b/deps/openssl/openssl/crypto/rand/drbg_lib.c @@ -0,0 +1,1159 @@ +/* + * Copyright 2011-2018 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 <string.h> +#include <openssl/crypto.h> +#include <openssl/err.h> +#include <openssl/rand.h> +#include "rand_lcl.h" +#include "internal/thread_once.h" +#include "internal/rand_int.h" +#include "internal/cryptlib_int.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: <master>, <public>, and <private>. + */ + +/* + * The <master> 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 <master> 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 <public> DRBG + * + * Used by default for generating random bytes using RAND_bytes(). + * + * The <public> DRBG is thread-local, i.e., there is one instance per thread. + */ +static CRYPTO_THREAD_LOCAL public_drbg; +/* + * The <private> DRBG + * + * Used by default for generating private keys using RAND_priv_bytes() + * + * The <private> 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; + } + + 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: + 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_count = rand_fork_count; + 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 accomadate 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 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; + } + + if (drbg->fork_count != rand_fork_count) { + drbg->fork_count = rand_fork_count; + 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, 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 avaible 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; +} |