rand_lib.c
/*
* Copyright 1995-2020 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
*/
/* We need to use some engine deprecated APIs */
#define OPENSSL_SUPPRESS_DEPRECATED
#include <stdio.h>
#include <time.h>
#include <limits.h>
#include <openssl/trace.h>
#include <openssl/err.h>
#include <openssl/conf.h>
#include "internal/cryptlib.h"
#include <openssl/opensslconf.h>
#include "crypto/rand.h"
#include "crypto/cryptlib.h"
#include <openssl/engine.h>
#include <openssl/core_names.h>
#include "internal/thread_once.h"
#include "rand_local.h"
#include "e_os.h"
#ifndef FIPS_MODULE
# include "prov/rand_pool.h"
# include "prov/seeding.h"
# ifndef OPENSSL_NO_ENGINE
/* non-NULL if default_RAND_meth is ENGINE-provided */
static ENGINE *funct_ref;
static CRYPTO_RWLOCK *rand_engine_lock;
# endif
static CRYPTO_RWLOCK *rand_meth_lock;
static const RAND_METHOD *default_RAND_meth;
static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
static int rand_inited = 0;
DEFINE_RUN_ONCE_STATIC(do_rand_init)
{
# ifndef OPENSSL_NO_ENGINE
rand_engine_lock = CRYPTO_THREAD_lock_new();
if (rand_engine_lock == NULL)
return 0;
# endif
rand_meth_lock = CRYPTO_THREAD_lock_new();
if (rand_meth_lock == NULL)
goto err;
if (!rand_pool_init())
goto err;
rand_inited = 1;
return 1;
err:
CRYPTO_THREAD_lock_free(rand_meth_lock);
rand_meth_lock = NULL;
# ifndef OPENSSL_NO_ENGINE
CRYPTO_THREAD_lock_free(rand_engine_lock);
rand_engine_lock = NULL;
# endif
return 0;
}
void rand_cleanup_int(void)
{
const RAND_METHOD *meth = default_RAND_meth;
if (!rand_inited)
return;
if (meth != NULL && meth->cleanup != NULL)
meth->cleanup();
RAND_set_rand_method(NULL);
rand_pool_cleanup();
# ifndef OPENSSL_NO_ENGINE
CRYPTO_THREAD_lock_free(rand_engine_lock);
rand_engine_lock = NULL;
# endif
CRYPTO_THREAD_lock_free(rand_meth_lock);
rand_meth_lock = NULL;
rand_inited = 0;
}
/*
* RAND_close_seed_files() ensures that any seed file descriptors are
* closed after use. This only applies to libcrypto/default provider,
* it does not apply to other providers.
*/
void RAND_keep_random_devices_open(int keep)
{
if (RUN_ONCE(&rand_init, do_rand_init))
rand_pool_keep_random_devices_open(keep);
}
/*
* 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.
*/
int RAND_poll(void)
{
const RAND_METHOD *meth = RAND_get_rand_method();
int ret = meth == RAND_OpenSSL();
if (meth == NULL)
return 0;
#ifndef OPENSSL_NO_DEPRECATED_3_0
if (!ret) {
/* fill random pool and seed the current legacy RNG */
RAND_POOL *pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
(RAND_DRBG_STRENGTH + 7) / 8,
RAND_POOL_MAX_LENGTH);
if (pool == NULL)
return 0;
if (prov_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);
}
#endif
return ret;
}
int RAND_set_rand_method(const RAND_METHOD *meth)
{
if (!RUN_ONCE(&rand_init, do_rand_init))
return 0;
CRYPTO_THREAD_write_lock(rand_meth_lock);
# ifndef OPENSSL_NO_ENGINE
ENGINE_finish(funct_ref);
funct_ref = NULL;
# endif
default_RAND_meth = meth;
CRYPTO_THREAD_unlock(rand_meth_lock);
return 1;
}
const RAND_METHOD *RAND_get_rand_method(void)
{
const RAND_METHOD *tmp_meth = NULL;
if (!RUN_ONCE(&rand_init, do_rand_init))
return NULL;
CRYPTO_THREAD_write_lock(rand_meth_lock);
if (default_RAND_meth == NULL) {
# ifndef OPENSSL_NO_ENGINE
ENGINE *e;
/* If we have an engine that can do RAND, use it. */
if ((e = ENGINE_get_default_RAND()) != NULL
&& (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
funct_ref = e;
default_RAND_meth = tmp_meth;
} else {
ENGINE_finish(e);
default_RAND_meth = &rand_meth;
}
# else
default_RAND_meth = &rand_meth;
# endif
}
tmp_meth = default_RAND_meth;
CRYPTO_THREAD_unlock(rand_meth_lock);
return tmp_meth;
}
# if !defined(OPENSSL_NO_ENGINE)
int RAND_set_rand_engine(ENGINE *engine)
{
const RAND_METHOD *tmp_meth = NULL;
if (!RUN_ONCE(&rand_init, do_rand_init))
return 0;
if (engine != NULL) {
if (!ENGINE_init(engine))
return 0;
tmp_meth = ENGINE_get_RAND(engine);
if (tmp_meth == NULL) {
ENGINE_finish(engine);
return 0;
}
}
CRYPTO_THREAD_write_lock(rand_engine_lock);
/* This function releases any prior ENGINE so call it first */
RAND_set_rand_method(tmp_meth);
funct_ref = engine;
CRYPTO_THREAD_unlock(rand_engine_lock);
return 1;
}
# endif
void RAND_seed(const void *buf, int num)
{
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth->seed != NULL)
meth->seed(buf, num);
}
void RAND_add(const void *buf, int num, double randomness)
{
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth->add != NULL)
meth->add(buf, num, randomness);
}
# if !defined(OPENSSL_NO_DEPRECATED_1_1_0)
int RAND_pseudo_bytes(unsigned char *buf, int num)
{
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth->pseudorand != NULL)
return meth->pseudorand(buf, num);
RANDerr(RAND_F_RAND_PSEUDO_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
return -1;
}
# endif
int RAND_status(void)
{
EVP_RAND_CTX *rand;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth != RAND_OpenSSL())
return meth->status != NULL ? meth->status() : 0;
if ((rand = RAND_get0_primary(NULL)) == NULL)
return 0;
return EVP_RAND_state(rand) == EVP_RAND_STATE_READY;
}
#else /* !FIPS_MODULE */
const RAND_METHOD *RAND_get_rand_method(void)
{
return NULL;
}
#endif /* !FIPS_MODULE */
/*
* This function is not part of RAND_METHOD, so if we're not using
* the default method, then just call RAND_bytes(). Otherwise make
* sure we're instantiated and use the private DRBG.
*/
int RAND_priv_bytes_ex(OSSL_LIB_CTX *ctx, unsigned char *buf, int num)
{
EVP_RAND_CTX *rand;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth != RAND_OpenSSL()) {
if (meth->bytes != NULL)
return meth->bytes(buf, num);
RANDerr(RAND_F_RAND_PRIV_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
return -1;
}
rand = RAND_get0_private(ctx);
if (rand != NULL)
return EVP_RAND_generate(rand, buf, num, 0, 0, NULL, 0);
return 0;
}
int RAND_priv_bytes(unsigned char *buf, int num)
{
return RAND_priv_bytes_ex(NULL, buf, num);
}
int RAND_bytes_ex(OSSL_LIB_CTX *ctx, unsigned char *buf, int num)
{
EVP_RAND_CTX *rand;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != NULL && meth != RAND_OpenSSL()) {
if (meth->bytes != NULL)
return meth->bytes(buf, num);
RANDerr(RAND_F_RAND_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
return -1;
}
rand = RAND_get0_public(ctx);
if (rand != NULL)
return EVP_RAND_generate(rand, buf, num, 0, 0, NULL, 0);
return 0;
}
int RAND_bytes(unsigned char *buf, int num)
{
return RAND_bytes_ex(NULL, buf, num);
}
typedef struct rand_global_st {
/*
* The three shared DRBG instances
*
* There are three shared DRBG instances: <primary>, <public>, and
* <private>. The <public> and <private> DRBGs are secondary ones.
* These are used for non-secret (e.g. nonces) and secret
* (e.g. private keys) data respectively.
*/
CRYPTO_RWLOCK *lock;
/*
* The <primary> 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 <primary> 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.
*/
EVP_RAND_CTX *primary;
/*
* The <public> DRBG
*
* Used by default for generating random bytes using RAND_bytes().
*
* The <public> secondary DRBG is thread-local, i.e., there is one instance
* per thread.
*/
CRYPTO_THREAD_LOCAL public;
/*
* The <private> DRBG
*
* Used by default for generating private keys using RAND_priv_bytes()
*
* The <private> secondary DRBG is thread-local, i.e., there is one
* instance per thread.
*/
CRYPTO_THREAD_LOCAL private;
/* Which RNG is being used by default and it's configuration settings */
char *rng_name;
char *rng_cipher;
char *rng_digest;
char *rng_propq;
} RAND_GLOBAL;
/*
* Initialize the OSSL_LIB_CTX global DRBGs on first use.
* Returns the allocated global data on success or NULL on failure.
*/
static void *rand_ossl_ctx_new(OSSL_LIB_CTX *libctx)
{
RAND_GLOBAL *dgbl = OPENSSL_zalloc(sizeof(*dgbl));
if (dgbl == NULL)
return NULL;
#ifndef FIPS_MODULE
/*
* We need to ensure that base libcrypto thread handling has been
* initialised.
*/
OPENSSL_init_crypto(0, NULL);
#endif
dgbl->lock = CRYPTO_THREAD_lock_new();
if (dgbl->lock == NULL)
goto err1;
if (!CRYPTO_THREAD_init_local(&dgbl->private, NULL))
goto err1;
if (!CRYPTO_THREAD_init_local(&dgbl->public, NULL))
goto err2;
return dgbl;
err2:
CRYPTO_THREAD_cleanup_local(&dgbl->private);
err1:
CRYPTO_THREAD_lock_free(dgbl->lock);
OPENSSL_free(dgbl);
return NULL;
}
static void rand_ossl_ctx_free(void *vdgbl)
{
RAND_GLOBAL *dgbl = vdgbl;
if (dgbl == NULL)
return;
CRYPTO_THREAD_lock_free(dgbl->lock);
EVP_RAND_CTX_free(dgbl->primary);
CRYPTO_THREAD_cleanup_local(&dgbl->private);
CRYPTO_THREAD_cleanup_local(&dgbl->public);
OPENSSL_free(dgbl->rng_name);
OPENSSL_free(dgbl->rng_cipher);
OPENSSL_free(dgbl->rng_digest);
OPENSSL_free(dgbl->rng_propq);
OPENSSL_free(dgbl);
}
static const OSSL_LIB_CTX_METHOD rand_drbg_ossl_ctx_method = {
rand_ossl_ctx_new,
rand_ossl_ctx_free,
};
static RAND_GLOBAL *rand_get_global(OSSL_LIB_CTX *libctx)
{
return ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_DRBG_INDEX,
&rand_drbg_ossl_ctx_method);
}
static void rand_delete_thread_state(void *arg)
{
OSSL_LIB_CTX *ctx = arg;
RAND_GLOBAL *dgbl = rand_get_global(ctx);
EVP_RAND_CTX *rand;
if (dgbl == NULL)
return;
rand = CRYPTO_THREAD_get_local(&dgbl->public);
CRYPTO_THREAD_set_local(&dgbl->public, NULL);
EVP_RAND_CTX_free(rand);
rand = CRYPTO_THREAD_get_local(&dgbl->private);
CRYPTO_THREAD_set_local(&dgbl->private, NULL);
EVP_RAND_CTX_free(rand);
}
static EVP_RAND_CTX *rand_new_drbg(OSSL_LIB_CTX *libctx, EVP_RAND_CTX *parent,
unsigned int reseed_interval,
time_t reseed_time_interval)
{
EVP_RAND *rand;
RAND_GLOBAL *dgbl = rand_get_global(libctx);
EVP_RAND_CTX *ctx;
OSSL_PARAM params[7], *p = params;
char *name, *cipher;
name = dgbl->rng_name != NULL ? dgbl->rng_name : "CTR-DRBG";
rand = EVP_RAND_fetch(libctx, name, dgbl->rng_propq);
if (rand == NULL) {
RANDerr(0, RAND_R_UNABLE_TO_FETCH_DRBG);
return NULL;
}
ctx = EVP_RAND_CTX_new(rand, parent);
EVP_RAND_free(rand);
if (ctx == NULL) {
RANDerr(0, RAND_R_UNABLE_TO_CREATE_DRBG);
return NULL;
}
/*
* Rather than trying to decode the DRBG settings, just pass them through
* and rely on the other end to ignore those it doesn't care about.
*/
cipher = dgbl->rng_cipher != NULL ? dgbl->rng_cipher : "AES-256-CTR";
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER,
cipher, 0);
if (dgbl->rng_digest != NULL)
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST,
dgbl->rng_digest, 0);
if (dgbl->rng_propq != NULL)
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_PROPERTIES,
dgbl->rng_propq, 0);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_ALG_PARAM_MAC, "HMAC", 0);
*p++ = OSSL_PARAM_construct_uint(OSSL_DRBG_PARAM_RESEED_REQUESTS,
&reseed_interval);
*p++ = OSSL_PARAM_construct_time_t(OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL,
&reseed_time_interval);
*p = OSSL_PARAM_construct_end();
if (!EVP_RAND_set_ctx_params(ctx, params)) {
RANDerr(0, RAND_R_ERROR_INITIALISING_DRBG);
EVP_RAND_CTX_free(ctx);
return NULL;
}
if (!EVP_RAND_instantiate(ctx, 0, 0, NULL, 0)) {
RANDerr(0, RAND_R_ERROR_INSTANTIATING_DRBG);
EVP_RAND_CTX_free(ctx);
return NULL;
}
return ctx;
}
/*
* Get the primary random generator.
* Returns pointer to its EVP_RAND_CTX on success, NULL on failure.
*
*/
EVP_RAND_CTX *RAND_get0_primary(OSSL_LIB_CTX *ctx)
{
RAND_GLOBAL *dgbl = rand_get_global(ctx);
if (dgbl == NULL)
return NULL;
if (dgbl->primary == NULL) {
if (!CRYPTO_THREAD_write_lock(dgbl->lock))
return NULL;
if (dgbl->primary == NULL)
dgbl->primary = rand_new_drbg(ctx, NULL, PRIMARY_RESEED_INTERVAL,
PRIMARY_RESEED_TIME_INTERVAL);
CRYPTO_THREAD_unlock(dgbl->lock);
}
return dgbl->primary;
}
/*
* Get the public random generator.
* Returns pointer to its EVP_RAND_CTX on success, NULL on failure.
*/
EVP_RAND_CTX *RAND_get0_public(OSSL_LIB_CTX *ctx)
{
RAND_GLOBAL *dgbl = rand_get_global(ctx);
EVP_RAND_CTX *rand, *primary;
if (dgbl == NULL)
return NULL;
rand = CRYPTO_THREAD_get_local(&dgbl->public);
if (rand == NULL) {
primary = RAND_get0_primary(ctx);
if (primary == NULL)
return NULL;
ctx = ossl_lib_ctx_get_concrete(ctx);
/*
* If the private is also NULL then this is the first time we've
* used this thread.
*/
if (CRYPTO_THREAD_get_local(&dgbl->private) == NULL
&& !ossl_init_thread_start(NULL, ctx, rand_delete_thread_state))
return NULL;
rand = rand_new_drbg(ctx, primary, SECONDARY_RESEED_INTERVAL,
SECONDARY_RESEED_TIME_INTERVAL);
CRYPTO_THREAD_set_local(&dgbl->public, rand);
}
return rand;
}
/*
* Get the private random generator.
* Returns pointer to its EVP_RAND_CTX on success, NULL on failure.
*/
EVP_RAND_CTX *RAND_get0_private(OSSL_LIB_CTX *ctx)
{
RAND_GLOBAL *dgbl = rand_get_global(ctx);
EVP_RAND_CTX *rand, *primary;
if (dgbl == NULL)
return NULL;
rand = CRYPTO_THREAD_get_local(&dgbl->private);
if (rand == NULL) {
primary = RAND_get0_primary(ctx);
if (primary == NULL)
return NULL;
ctx = ossl_lib_ctx_get_concrete(ctx);
/*
* If the public is also NULL then this is the first time we've
* used this thread.
*/
if (CRYPTO_THREAD_get_local(&dgbl->public) == NULL
&& !ossl_init_thread_start(NULL, ctx, rand_delete_thread_state))
return NULL;
rand = rand_new_drbg(ctx, primary, SECONDARY_RESEED_INTERVAL,
SECONDARY_RESEED_TIME_INTERVAL);
CRYPTO_THREAD_set_local(&dgbl->private, rand);
}
return rand;
}
#ifndef FIPS_MODULE
static int random_set_string(char **p, const char *s)
{
char *d = OPENSSL_strdup(s);
if (d == NULL) {
CRYPTOerr(0, ERR_R_MALLOC_FAILURE);
return 0;
}
OPENSSL_free(*p);
*p = d;
return 1;
}
/*
* Load the DRBG definitions from a configuration file.
*/
static int random_conf_init(CONF_IMODULE *md, const CONF *cnf)
{
STACK_OF(CONF_VALUE) *elist;
CONF_VALUE *cval;
RAND_GLOBAL *dgbl = rand_get_global(cnf->libctx);
int i, r = 1;
OSSL_TRACE1(CONF, "Loading random module: section %s\n",
CONF_imodule_get_value(md));
/* Value is a section containing RANDOM configuration */
elist = NCONF_get_section(cnf, CONF_imodule_get_value(md));
if (elist == NULL) {
CRYPTOerr(0, CRYPTO_R_RANDOM_SECTION_ERROR);
return 0;
}
for (i = 0; i < sk_CONF_VALUE_num(elist); i++) {
cval = sk_CONF_VALUE_value(elist, i);
if (strcasecmp(cval->name, "random") == 0) {
if (!random_set_string(&dgbl->rng_name, cval->value))
return 0;
} else if (strcasecmp(cval->name, "cipher") == 0) {
if (!random_set_string(&dgbl->rng_cipher, cval->value))
return 0;
} else if (strcasecmp(cval->name, "digest") == 0) {
if (!random_set_string(&dgbl->rng_digest, cval->value))
return 0;
} else if (strcasecmp(cval->name, "properties") == 0) {
if (!random_set_string(&dgbl->rng_propq, cval->value))
return 0;
} else {
CRYPTOerr(0, CRYPTO_R_UNKNOWN_NAME_IN_RANDOM_SECTION);
ERR_add_error_data(4, "name=", cval->name, ", value=", cval->value);
r = 0;
}
}
return r;
}
static void random_conf_deinit(CONF_IMODULE *md)
{
OSSL_TRACE(CONF, "Cleaned up random\n");
}
void ossl_random_add_conf_module(void)
{
OSSL_TRACE(CONF, "Adding config module 'random'\n");
CONF_module_add("random", random_conf_init, random_conf_deinit);
}
#endif
