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c4d0221405
openssl/providers/implementations/rands/drbg.c
Pauli c4d0221405 coverity: CID 1464987: USE AFTER FREE 
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12309)
2020-07-05 13:20:09 +10:00

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/*
* Copyright 2011-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (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 <openssl/evp.h>
#include "crypto/rand.h"
#include "drbg_local.h"
#include "internal/thread_once.h"
#include "crypto/cryptlib.h"
#include "prov/seeding.h"
#include "prov/rand_pool.h"
#include "prov/provider_ctx.h"
#include "prov/providercommonerr.h"
/*
* Support framework for NIST SP 800-90A DRBG
*
* See manual page PROV_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.)
*/
/* NIST SP 800-90A DRBG recommends the use of a personalization string. */
static const char ossl_pers_string[] = DRBG_DEFAULT_PERS_STRING;
static const OSSL_DISPATCH *find_call(const OSSL_DISPATCH *dispatch,
int function);
static int rand_drbg_restart(PROV_DRBG *drbg);
int drbg_lock(void *vctx)
{
PROV_DRBG *drbg = vctx;
if (drbg == NULL || drbg->lock == NULL)
return 1;
return CRYPTO_THREAD_write_lock(drbg->lock);
}
void drbg_unlock(void *vctx)
{
PROV_DRBG *drbg = vctx;
if (drbg != NULL && drbg->lock != NULL)
CRYPTO_THREAD_unlock(drbg->lock);
}
static int drbg_lock_parent(PROV_DRBG *drbg)
{
void *parent = drbg->parent;
if (parent != NULL
&& drbg->parent_lock != NULL
&& !drbg->parent_lock(parent)) {
ERR_raise(ERR_LIB_PROV, PROV_R_PARENT_LOCKING_NOT_ENABLED);
return 0;
}
return 1;
}
static void drbg_unlock_parent(PROV_DRBG *drbg)
{
void *parent = drbg->parent;
if (parent != NULL && drbg->parent_unlock != NULL)
drbg->parent_unlock(parent);
}
static int get_parent_strength(PROV_DRBG *drbg, unsigned int *str)
{
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
void *parent = drbg->parent;
int res;
if (drbg->parent_get_ctx_params == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_GET_PARENT_STRENGTH);
return 0;
}
*params = OSSL_PARAM_construct_uint(OSSL_RAND_PARAM_STRENGTH, str);
if (!drbg_lock_parent(drbg)) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOCK_PARENT);
return 0;
}
res = drbg->parent_get_ctx_params(parent, params);
drbg_unlock_parent(drbg);
if (!res) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_GET_PARENT_STRENGTH);
return 0;
}
return 1;
}
static unsigned int get_parent_reseed_count(PROV_DRBG *drbg)
{
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
void *parent = drbg->parent;
unsigned int r;
*params = OSSL_PARAM_construct_uint(OSSL_DRBG_PARAM_RESEED_CTR, &r);
if (!drbg_lock_parent(drbg)) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOCK_PARENT);
goto err;
}
if (!drbg->parent_get_ctx_params(parent, params)) {
drbg_unlock_parent(drbg);
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_GET_RESEED_PROP_CTR);
goto err;
}
drbg_unlock_parent(drbg);
return r;
err:
r = tsan_load(&drbg->reseed_counter) - 2;
if (r == 0)
r = UINT_MAX;
return r;
}
/*
* 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().
*
* Otherwise, the entropy is polled from the system entropy sources
* using prov_pool_acquire_entropy().
*
* If a random pool has been added to the DRBG using RAND_add(), then
* its entropy will be used up first.
*/
static size_t prov_drbg_get_entropy(PROV_DRBG *drbg, unsigned char **pout,
int entropy, size_t min_len,
size_t max_len, int prediction_resistance)
{
size_t ret = 0;
size_t entropy_available = 0;
RAND_POOL *pool;
unsigned int p_str;
if (drbg->parent != NULL) {
if (!get_parent_strength(drbg, &p_str))
return 0;
if (drbg->strength > p_str) {
/*
* We currently don't support the algorithm from NIST SP 800-90C
* 10.1.2 to use a weaker DRBG as source
*/
RANDerr(0, PROV_R_PARENT_STRENGTH_TOO_WEAK);
return 0;
}
}
if (drbg->seed_pool != NULL) {
pool = drbg->seed_pool;
pool->entropy_requested = entropy;
} else {
pool = rand_pool_new(entropy, 1, min_len, max_len);
if (pool == NULL) {
ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
return 0;
}
}
if (drbg->parent != NULL) {
size_t bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
unsigned char *buffer = rand_pool_add_begin(pool, bytes_needed);
if (buffer != NULL) {
size_t bytes = 0;
/*
* Get random data from parent. Include our address as additional input,
* in order to provide some additional distinction between different
* DRBG child instances.
* Our lock is already held, but we need to lock our parent before
* generating bits from it. (Note: taking the lock will be a no-op
* if locking if drbg->parent->lock == NULL.)
*/
if (drbg->parent_generate == NULL)
goto err;
drbg_lock_parent(drbg);
if (drbg->parent_generate(drbg->parent, buffer, bytes_needed,
drbg->strength, prediction_resistance,
(unsigned char *)&drbg,
sizeof(drbg)) != 0)
bytes = bytes_needed;
drbg_unlock_parent(drbg);
drbg->parent_reseed_counter = get_parent_reseed_count(drbg);
rand_pool_add_end(pool, bytes, 8 * bytes);
entropy_available = rand_pool_entropy_available(pool);
}
} else {
/* Get entropy by polling system entropy sources. */
entropy_available = prov_pool_acquire_entropy(pool);
}
if (entropy_available > 0) {
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
}
err:
if (drbg->seed_pool == NULL)
rand_pool_free(pool);
return ret;
}
/*
* Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
*
*/
static void prov_drbg_cleanup_entropy(PROV_DRBG *drbg,
unsigned char *out, size_t outlen)
{
OSSL_PARAM params[3], *p = params;
if (drbg->get_entropy_fn != NULL) {
if (drbg->cleanup_entropy_fn != NULL) {
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_SIZE,
&outlen);
*p++ = OSSL_PARAM_construct_octet_ptr(OSSL_DRBG_PARAM_RANDOM_DATA,
(void **)&out, 0);
*p = OSSL_PARAM_construct_end();
drbg->cleanup_entropy_fn(params, drbg->callback_arg);
}
} else if (drbg->seed_pool == NULL) {
OPENSSL_secure_clear_free(out, outlen);
}
}
static size_t get_entropy(PROV_DRBG *drbg, unsigned char **pout, int entropy,
size_t min_len, size_t max_len,
int prediction_resistance)
{
if (drbg->get_entropy_fn != NULL) {
OSSL_PARAM params[6], *p = params;
OSSL_PARAM out[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
*p++ = OSSL_PARAM_construct_int(OSSL_DRBG_PARAM_ENTROPY_REQUIRED,
&entropy);
*p++ = OSSL_PARAM_construct_int(OSSL_DRBG_PARAM_PREDICTION_RESISTANCE,
&prediction_resistance);
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_MIN_LENGTH,
&min_len);
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_MAX_LENGTH,
&max_len);
*p = OSSL_PARAM_construct_end();
*out = OSSL_PARAM_construct_octet_ptr(OSSL_DRBG_PARAM_RANDOM_DATA,
(void **)pout, 0);
if (drbg->get_entropy_fn(params, out, drbg->callback_arg))
return out->return_size;
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_GET_ENTROPY);
return 0;
}
#ifdef FIPS_MODULE
if (drbg->parent == NULL)
return prov_crngt_get_entropy(drbg, pout, entropy, min_len, max_len,
prediction_resistance);
#endif
return prov_drbg_get_entropy(drbg, pout, entropy, min_len, max_len,
prediction_resistance);
}
static void cleanup_entropy(PROV_DRBG *drbg, unsigned char *out, size_t outlen)
{
#ifdef FIPS_MODULE
if (drbg->parent == NULL)
prov_crngt_cleanup_entropy(drbg, out, outlen);
else
#endif
prov_drbg_cleanup_entropy(drbg, out, outlen);
}
#ifndef PROV_RAND_GET_RANDOM_NONCE
typedef struct prov_drbg_nonce_global_st {
CRYPTO_RWLOCK *rand_nonce_lock;
int rand_nonce_count;
} PROV_DRBG_NONCE_GLOBAL;
/*
* drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce()
* which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since
* drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock
* to be in a different global data object. Otherwise we will go into an
* infinite recursion loop.
*/
static void *prov_drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx)
{
PROV_DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl));
if (dngbl == NULL)
return NULL;
dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new();
if (dngbl->rand_nonce_lock == NULL) {
OPENSSL_free(dngbl);
return NULL;
}
return dngbl;
}
static void prov_drbg_nonce_ossl_ctx_free(void *vdngbl)
{
PROV_DRBG_NONCE_GLOBAL *dngbl = vdngbl;
if (dngbl == NULL)
return;
CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock);
OPENSSL_free(dngbl);
}
static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = {
prov_drbg_nonce_ossl_ctx_new,
prov_drbg_nonce_ossl_ctx_free,
};
/* Get a nonce from the operating system */
static size_t prov_drbg_get_nonce(PROV_DRBG *drbg,
unsigned char **pout,
int entropy, size_t min_len, size_t max_len)
{
size_t ret = 0, n;
RAND_POOL *pool;
unsigned char *buf = NULL;
OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(drbg->provctx);
PROV_DRBG_NONCE_GLOBAL *dngbl
= openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_NONCE_INDEX,
&drbg_nonce_ossl_ctx_method);
OSSL_PARAM params[5], *p = params;
OSSL_PARAM out[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
struct {
void *instance;
int count;
} data;
if (dngbl == NULL)
return 0;
if (drbg->get_nonce_fn != NULL) {
*p++ = OSSL_PARAM_construct_int(OSSL_DRBG_PARAM_ENTROPY_REQUIRED,
&entropy);
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_MIN_LENGTH,
&min_len);
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_MAX_LENGTH,
&max_len);
*p = OSSL_PARAM_construct_end();
*out = OSSL_PARAM_construct_octet_ptr(OSSL_DRBG_PARAM_RANDOM_DATA,
(void **)pout, 0);
if (drbg->get_nonce_fn(params, out, drbg->callback_arg))
return out->return_size;
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_GET_NONCE);
return 0;
}
if (drbg->parent != NULL) {
if (drbg->parent_nonce != NULL) {
n = drbg->parent_nonce(drbg->parent, NULL, 0, drbg->min_noncelen,
drbg->max_noncelen);
if (n > 0 && (buf = OPENSSL_malloc(n)) != NULL) {
ret = drbg->parent_nonce(drbg->parent, buf, 0,
drbg->min_noncelen,
drbg->max_noncelen);
if (ret == n) {
*pout = buf;
return ret;
}
OPENSSL_free(buf);
}
}
}
/* Use the built in nonce source */
memset(&data, 0, sizeof(data));
pool = rand_pool_new(0, 0, min_len, max_len);
if (pool == NULL)
return 0;
if (prov_pool_add_nonce_data(pool) == 0)
goto err;
data.instance = drbg;
CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count,
dngbl->rand_nonce_lock);
if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0)
goto err;
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
err:
rand_pool_free(pool);
return ret;
}
static void prov_drbg_clear_nonce(PROV_DRBG *drbg, unsigned char *nonce,
size_t noncelen)
{
OSSL_PARAM params[3], *p = params;
if (drbg->get_nonce_fn != NULL) {
if (drbg->cleanup_nonce_fn != NULL) {
*p++ = OSSL_PARAM_construct_size_t(OSSL_DRBG_PARAM_SIZE,
&noncelen);
*p++ = OSSL_PARAM_construct_octet_ptr(OSSL_DRBG_PARAM_RANDOM_DATA,
(void **)&nonce, 0);
*p = OSSL_PARAM_construct_end();
drbg->cleanup_nonce_fn(params, drbg->callback_arg);
}
} else {
OPENSSL_clear_free(nonce, noncelen);
}
}
#else
# define prov_drbg_clear_nonce(drbg, nonce, len) \
OPENSSL_clear_free((nonce), (len))
#endif /* PROV_RAND_GET_RANDOM_NONCE */
/*
* 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 PROV_DRBG_instantiate(PROV_DRBG *drbg, unsigned int strength,
int prediction_resistance,
const unsigned char *pers, size_t perslen)
{
unsigned char *nonce = NULL, *entropy = NULL;
size_t noncelen = 0, entropylen = 0;
size_t min_entropy, min_entropylen, max_entropylen;
if (strength > drbg->strength) {
PROVerr(0, PROV_R_INSUFFICIENT_DRBG_STRENGTH);
goto end;
}
min_entropy = drbg->strength;
min_entropylen = drbg->min_entropylen;
max_entropylen = drbg->max_entropylen;
if (pers == NULL) {
pers = (const unsigned char *)ossl_pers_string;
perslen = sizeof(ossl_pers_string);
}
if (perslen > drbg->max_perslen) {
PROVerr(0, PROV_R_PERSONALISATION_STRING_TOO_LONG);
goto end;
}
if (drbg->state != EVP_RAND_STATE_UNINITIALISED) {
if (drbg->state == EVP_RAND_STATE_ERROR)
PROVerr(0, PROV_R_IN_ERROR_STATE);
else
PROVerr(0, PROV_R_ALREADY_INSTANTIATED);
goto end;
}
drbg->state = EVP_RAND_STATE_ERROR;
if (drbg->min_noncelen > 0) {
if (drbg->parent_nonce != NULL) {
noncelen = drbg->parent_nonce(drbg->parent, NULL, drbg->strength,
drbg->min_noncelen,
drbg->max_noncelen);
if (noncelen == 0) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_NONCE);
goto end;
}
nonce = OPENSSL_malloc(noncelen);
if (nonce == NULL) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_NONCE);
goto end;
}
if (noncelen != drbg->parent_nonce(drbg->parent, nonce,
drbg->strength,
drbg->min_noncelen,
drbg->max_noncelen)) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_NONCE);
goto end;
}
#ifndef PROV_RAND_GET_RANDOM_NONCE
} else if (drbg->parent != NULL) {
#endif
/*
* 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
* required and there is no parental nonce capability.
*/
min_entropy += drbg->strength / 2;
min_entropylen += drbg->min_noncelen;
max_entropylen += drbg->max_noncelen;
}
#ifndef PROV_RAND_GET_RANDOM_NONCE
else { /* parent == NULL */
noncelen = prov_drbg_get_nonce(drbg, &nonce, drbg->strength / 2,
drbg->min_noncelen,
drbg->max_noncelen);
if (noncelen < drbg->min_noncelen
|| noncelen > drbg->max_noncelen) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_NONCE);
goto end;
}
}
#endif
}
drbg->reseed_next_counter = tsan_load(&drbg->reseed_counter);
if (drbg->reseed_next_counter) {
drbg->reseed_next_counter++;
if (!drbg->reseed_next_counter)
drbg->reseed_next_counter = 1;
}
entropylen = get_entropy(drbg, &entropy, min_entropy,
min_entropylen, max_entropylen,
prediction_resistance);
if (entropylen < min_entropylen
|| entropylen > max_entropylen) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
if (!drbg->instantiate(drbg, entropy, entropylen, nonce, noncelen,
pers, perslen)) {
PROVerr(0, PROV_R_ERROR_INSTANTIATING_DRBG);
goto end;
}
drbg->state = EVP_RAND_STATE_READY;
drbg->reseed_gen_counter = 1;
drbg->reseed_time = time(NULL);
tsan_store(&drbg->reseed_counter, drbg->reseed_next_counter);
end:
if (entropy != NULL)
cleanup_entropy(drbg, entropy, entropylen);
prov_drbg_clear_nonce(drbg, nonce, noncelen);
if (drbg->state == EVP_RAND_STATE_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 PROV_DRBG_uninstantiate(PROV_DRBG *drbg)
{
drbg->state = EVP_RAND_STATE_UNINITIALISED;
return 1;
}
/*
* 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 PROV_DRBG_reseed(PROV_DRBG *drbg, int prediction_resistance,
const unsigned char *ent, size_t ent_len,
const unsigned char *adin, size_t adinlen)
{
unsigned char *entropy = NULL;
size_t entropylen = 0;
if (drbg->state != EVP_RAND_STATE_READY) {
/* try to recover from previous errors */
rand_drbg_restart(drbg);
if (drbg->state == EVP_RAND_STATE_ERROR) {
PROVerr(0, PROV_R_IN_ERROR_STATE);
return 0;
}
if (drbg->state == EVP_RAND_STATE_UNINITIALISED) {
PROVerr(0, PROV_R_NOT_INSTANTIATED);
return 0;
}
}
if (ent != NULL) {
if (ent_len < drbg->min_entropylen) {
RANDerr(0, RAND_R_ENTROPY_OUT_OF_RANGE);
drbg->state = EVP_RAND_STATE_ERROR;
return 0;
}
if (ent_len > drbg->max_entropylen) {
RANDerr(0, RAND_R_ENTROPY_INPUT_TOO_LONG);
drbg->state = EVP_RAND_STATE_ERROR;
return 0;
}
}
if (adin == NULL) {
adinlen = 0;
} else if (adinlen > drbg->max_adinlen) {
PROVerr(0, PROV_R_ADDITIONAL_INPUT_TOO_LONG);
return 0;
}
drbg->state = EVP_RAND_STATE_ERROR;
drbg->reseed_next_counter = tsan_load(&drbg->reseed_counter);
if (drbg->reseed_next_counter) {
drbg->reseed_next_counter++;
if (!drbg->reseed_next_counter)
drbg->reseed_next_counter = 1;
}
if (ent != NULL) {
#ifdef FIP_MODULE
/*
* NIST SP-800-90A mandates that entropy *shall not* be provided
* by the consuming application. Instead the data is added as additional
* input.
*
* (NIST SP-800-90Ar1, Sections 9.1 and 9.2)
*/
if (!drbg->reseed(drbg, NULL, 0, ent, ent_len)) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_RESEED);
return 0;
}
#else
if (!drbg->reseed(drbg, ent, ent_len, adin, adinlen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_RESEED);
return 0;
}
/* There isn't much point adding the same additional input twice */
adin = NULL;
adinlen = 0;
#endif
}
/* Reseed using our sources in addition */
entropylen = get_entropy(drbg, &entropy, drbg->strength,
drbg->min_entropylen, drbg->max_entropylen,
prediction_resistance);
if (entropylen < drbg->min_entropylen
|| entropylen > drbg->max_entropylen) {
PROVerr(0, PROV_R_ERROR_RETRIEVING_ENTROPY);
goto end;
}
if (!drbg->reseed(drbg, entropy, entropylen, adin, adinlen))
goto end;
drbg->state = EVP_RAND_STATE_READY;
drbg->reseed_gen_counter = 1;
drbg->reseed_time = time(NULL);
tsan_store(&drbg->reseed_counter, drbg->reseed_next_counter);
if (drbg->parent != NULL)
drbg->parent_reseed_counter = get_parent_reseed_count(drbg);
end:
cleanup_entropy(drbg, entropy, entropylen);
if (drbg->state == EVP_RAND_STATE_READY)
return 1;
return 0;
}
/*
* 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 PROV_DRBG_generate(PROV_DRBG *drbg, unsigned char *out, size_t outlen,
unsigned int strength, int prediction_resistance,
const unsigned char *adin, size_t adinlen)
{
int fork_id;
int reseed_required = 0;
if (drbg->state != EVP_RAND_STATE_READY) {
/* try to recover from previous errors */
rand_drbg_restart(drbg);
if (drbg->state == EVP_RAND_STATE_ERROR) {
PROVerr(0, PROV_R_IN_ERROR_STATE);
return 0;
}
if (drbg->state == EVP_RAND_STATE_UNINITIALISED) {
PROVerr(0, PROV_R_NOT_INSTANTIATED);
return 0;
}
}
if (strength > drbg->strength) {
PROVerr(0, PROV_R_INSUFFICIENT_DRBG_STRENGTH);
return 0;
}
if (outlen > drbg->max_request) {
PROVerr(0, PROV_R_REQUEST_TOO_LARGE_FOR_DRBG);
return 0;
}
if (adinlen > drbg->max_adinlen) {
PROVerr(0, PROV_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
&& get_parent_reseed_count(drbg) != drbg->parent_reseed_counter)
reseed_required = 1;
if (reseed_required || prediction_resistance) {
if (!PROV_DRBG_reseed(drbg, prediction_resistance, NULL, 0,
adin, adinlen)) {
PROVerr(0, PROV_R_RESEED_ERROR);
return 0;
}
adin = NULL;
adinlen = 0;
}
if (!drbg->generate(drbg, out, outlen, adin, adinlen)) {
drbg->state = EVP_RAND_STATE_ERROR;
PROVerr(0, PROV_R_GENERATE_ERROR);
return 0;
}
drbg->reseed_gen_counter++;
return 1;
}
/*
* 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.
*/
static int rand_drbg_restart(PROV_DRBG *drbg)
{
if (drbg->seed_pool != NULL) {
drbg->state = EVP_RAND_STATE_ERROR;
rand_pool_free(drbg->seed_pool);
drbg->seed_pool = NULL;
RANDerr(0, ERR_R_INTERNAL_ERROR);
return 0;
}
/* repair error state */
if (drbg->state == EVP_RAND_STATE_ERROR)
drbg->uninstantiate(drbg);
/* repair uninitialized state */
if (drbg->state == EVP_RAND_STATE_UNINITIALISED)
/* reinstantiate drbg */
PROV_DRBG_instantiate(drbg, drbg->strength, 0, NULL, 0);
rand_pool_free(drbg->seed_pool);
drbg->seed_pool = NULL;
return drbg->state == EVP_RAND_STATE_READY;
}
/* Provider support from here down */
static const OSSL_DISPATCH *find_call(const OSSL_DISPATCH *dispatch,
int function)
{
if (dispatch != NULL)
while (dispatch->function_id != 0) {
if (dispatch->function_id == function)
return dispatch;
dispatch++;
}
return NULL;
}
int drbg_enable_locking(void *vctx)
{
PROV_DRBG *drbg = vctx;
if (drbg != NULL && drbg->lock == NULL) {
if (drbg->parent_enable_locking != NULL)
if (!drbg->parent_enable_locking(drbg->parent)) {
ERR_raise(ERR_LIB_PROV, PROV_R_PARENT_LOCKING_NOT_ENABLED);
return 0;
}
drbg->lock = CRYPTO_THREAD_lock_new();
if (drbg->lock == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_CREATE_LOCK);
return 0;
}
}
return 1;
}
/*
* 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.
* This also requires the parent's provider context and the parent's lock.
*
* Returns a pointer to the new DRBG instance on success, NULL on failure.
*/
PROV_DRBG *prov_rand_drbg_new
(void *provctx, void *parent, const OSSL_DISPATCH *p_dispatch,
int (*dnew)(PROV_DRBG *ctx),
int (*instantiate)(PROV_DRBG *drbg,
const unsigned char *entropy, size_t entropylen,
const unsigned char *nonce, size_t noncelen,
const unsigned char *pers, size_t perslen),
int (*uninstantiate)(PROV_DRBG *ctx),
int (*reseed)(PROV_DRBG *drbg, const unsigned char *ent, size_t ent_len,
const unsigned char *adin, size_t adin_len),
int (*generate)(PROV_DRBG *, unsigned char *out, size_t outlen,
const unsigned char *adin, size_t adin_len))
{
PROV_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
unsigned int p_str;
const OSSL_DISPATCH *pfunc;
if (drbg == NULL) {
ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
return NULL;
}
drbg->provctx = provctx;
drbg->instantiate = instantiate;
drbg->uninstantiate = uninstantiate;
drbg->reseed = reseed;
drbg->generate = generate;
drbg->fork_id = openssl_get_fork_id();
/* Extract parent's functions */
drbg->parent = parent;
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_ENABLE_LOCKING)) != NULL)
drbg->parent_enable_locking = OSSL_FUNC_rand_enable_locking(pfunc);
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_LOCK)) != NULL)
drbg->parent_lock = OSSL_FUNC_rand_lock(pfunc);
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_UNLOCK)) != NULL)
drbg->parent_unlock = OSSL_FUNC_rand_unlock(pfunc);
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_GET_CTX_PARAMS)) != NULL)
drbg->parent_get_ctx_params = OSSL_FUNC_rand_get_ctx_params(pfunc);
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_GENERATE)) != NULL)
drbg->parent_generate = OSSL_FUNC_rand_generate(pfunc);
if ((pfunc = find_call(p_dispatch, OSSL_FUNC_RAND_NONCE)) != NULL)
drbg->parent_nonce = OSSL_FUNC_rand_nonce(pfunc);
/* Set some default maximums up */
drbg->max_entropylen = DRBG_MAX_LENGTH;
drbg->max_noncelen = DRBG_MAX_LENGTH;
drbg->max_perslen = DRBG_MAX_LENGTH;
drbg->max_adinlen = DRBG_MAX_LENGTH;
drbg->reseed_gen_counter = 1;
drbg->reseed_counter = 1;
drbg->reseed_interval = RESEED_INTERVAL;
drbg->reseed_time_interval = TIME_INTERVAL;
if (!dnew(drbg))
goto err;
if (parent != NULL) {
if (!get_parent_strength(drbg, &p_str))
goto err;
if (drbg->strength > p_str) {
/*
* We currently don't support the algorithm from NIST SP 800-90C
* 10.1.2 to use a weaker DRBG as source
*/
ERR_raise(ERR_LIB_PROV, PROV_R_PARENT_STRENGTH_TOO_WEAK);
goto err;
}
}
return drbg;
err:
prov_rand_drbg_free(drbg);
return NULL;
}
void prov_rand_drbg_free(PROV_DRBG *drbg)
{
if (drbg == NULL)
return;
rand_pool_free(drbg->adin_pool);
CRYPTO_THREAD_lock_free(drbg->lock);
OPENSSL_free(drbg);
}
int drbg_get_ctx_params(PROV_DRBG *drbg, OSSL_PARAM params[])
{
OSSL_PARAM *p;
p = OSSL_PARAM_locate(params, OSSL_RAND_PARAM_STATE);
if (p != NULL && !OSSL_PARAM_set_int(p, drbg->state))
return 0;
p = OSSL_PARAM_locate(params, OSSL_RAND_PARAM_STRENGTH);
if (p != NULL && !OSSL_PARAM_set_int(p, drbg->strength))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAX_REQUEST);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->max_request))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MIN_ENTROPYLEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->min_entropylen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAX_ENTROPYLEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->max_entropylen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MIN_NONCELEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->min_noncelen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAX_NONCELEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->max_noncelen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAX_PERSLEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->max_perslen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAX_ADINLEN);
if (p != NULL && !OSSL_PARAM_set_size_t(p, drbg->max_adinlen))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_RESEED_REQUESTS);
if (p != NULL && !OSSL_PARAM_set_uint(p, drbg->reseed_interval))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_RESEED_TIME);
if (p != NULL && !OSSL_PARAM_set_time_t(p, drbg->reseed_time))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL);
if (p != NULL && !OSSL_PARAM_set_time_t(p, drbg->reseed_time_interval))
return 0;
p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_RESEED_CTR);
if (p != NULL
&& !OSSL_PARAM_set_uint(p, tsan_load(&drbg->reseed_counter)))
return 0;
return 1;
}
int drbg_set_ctx_params(PROV_DRBG *drbg, const OSSL_PARAM params[])
{
const OSSL_PARAM *p;
p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_RESEED_REQUESTS);
if (p != NULL && !OSSL_PARAM_get_uint(p, &drbg->reseed_interval))
return 0;
p = OSSL_PARAM_locate_const(params, OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL);
if (p != NULL && !OSSL_PARAM_get_time_t(p, &drbg->reseed_time_interval))
return 0;
return 1;
}
int drbg_set_callbacks(void *vctx, OSSL_INOUT_CALLBACK *get_entropy_fn,
OSSL_CALLBACK *cleanup_entropy_fn,
OSSL_INOUT_CALLBACK *get_nonce_fn,
OSSL_CALLBACK *cleanup_nonce_fn, void *arg)
{
PROV_DRBG *drbg = vctx;
if (drbg->state != EVP_RAND_STATE_UNINITIALISED
|| drbg->parent != NULL)
return 0;
drbg->get_entropy_fn = get_entropy_fn;
drbg->cleanup_entropy_fn = cleanup_entropy_fn;
drbg->get_nonce_fn = get_nonce_fn;
drbg->cleanup_nonce_fn = cleanup_nonce_fn;
drbg->callback_arg = arg;
return 1;
}
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