openssl/crypto/rand/rand_lib.c
Dr. Matthias St. Pierre 849529257c drbg: ensure fork-safety without using a pthread_atfork handler
When the new OpenSSL CSPRNG was introduced in version 1.1.1,
it was announced in the release notes that it would be fork-safe,
which the old CSPRNG hadn't been.

The fork-safety was implemented using a fork count, which was
incremented by a pthread_atfork handler. Initially, this handler
was enabled by default. Unfortunately, the default behaviour
had to be changed for other reasons in commit b5319bdbd0, so
the new OpenSSL CSPRNG failed to keep its promise.

This commit restores the fork-safety using a different approach.
It replaces the fork count by a fork id, which coincides with
the process id on UNIX-like operating systems and is zero on other
operating systems. It is used to detect when an automatic reseed
after a fork is necessary.

To prevent a future regression, it also adds a test to verify that
the child reseeds after fork.

CVE-2019-1549

Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9832)
2019-09-11 11:22:18 +02:00

916 lines
25 KiB
C

/*
* Copyright 1995-2018 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 <stdio.h>
#include <time.h>
#include "internal/cryptlib.h"
#include <openssl/opensslconf.h>
#include "internal/rand_int.h"
#include <openssl/engine.h>
#include "internal/thread_once.h"
#include "rand_lcl.h"
#include "e_os.h"
#ifndef FIPS_MODE
# 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;
#endif /* FIPS_MODE */
#ifdef OPENSSL_RAND_SEED_RDTSC
/*
* IMPORTANT NOTE: It is not currently possible to use this code
* because we are not sure about the amount of randomness it provides.
* Some SP900 tests have been run, but there is internal skepticism.
* So for now this code is not used.
*/
# error "RDTSC enabled? Should not be possible!"
/*
* Acquire entropy from high-speed clock
*
* Since we get some randomness from the low-order bits of the
* high-speed clock, it can help.
*
* Returns the total entropy count, if it exceeds the requested
* entropy count. Otherwise, returns an entropy count of 0.
*/
size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
{
unsigned char c;
int i;
if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
for (i = 0; i < TSC_READ_COUNT; i++) {
c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
rand_pool_add(pool, &c, 1, 4);
}
}
return rand_pool_entropy_available(pool);
}
#endif
#ifdef OPENSSL_RAND_SEED_RDCPU
size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
/*
* Acquire entropy using Intel-specific cpu instructions
*
* Uses the RDSEED instruction if available, otherwise uses
* RDRAND if available.
*
* For the differences between RDSEED and RDRAND, and why RDSEED
* is the preferred choice, see https://goo.gl/oK3KcN
*
* Returns the total entropy count, if it exceeds the requested
* entropy count. Otherwise, returns an entropy count of 0.
*/
size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
{
size_t bytes_needed;
unsigned char *buffer;
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
if (bytes_needed > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
if (buffer != NULL) {
/* Whichever comes first, use RDSEED, RDRAND or nothing */
if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
== bytes_needed) {
rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
}
} else if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
== bytes_needed) {
rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
}
} else {
rand_pool_add_end(pool, 0, 0);
}
}
}
return rand_pool_entropy_available(pool);
}
#endif
/*
* 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 rand_pool_acquire_entropy().
*
* If a random pool has been added to the DRBG using RAND_add(), then
* its entropy will be used up first.
*/
size_t rand_drbg_get_entropy(RAND_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;
if (drbg->parent != NULL && drbg->strength > drbg->parent->strength) {
/*
* We currently don't support the algorithm from NIST SP 800-90C
* 10.1.2 to use a weaker DRBG as source
*/
RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_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, drbg->secure, min_len, max_len);
if (pool == NULL)
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 from parent, include our state as additional input.
* 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.)
*/
rand_drbg_lock(drbg->parent);
if (RAND_DRBG_generate(drbg->parent,
buffer, bytes_needed,
prediction_resistance,
NULL, 0) != 0)
bytes = bytes_needed;
drbg->reseed_next_counter
= tsan_load(&drbg->parent->reseed_prop_counter);
rand_drbg_unlock(drbg->parent);
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 = rand_pool_acquire_entropy(pool);
}
if (entropy_available > 0) {
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
}
if (drbg->seed_pool == NULL)
rand_pool_free(pool);
return ret;
}
/*
* Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
*
*/
void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen)
{
if (drbg->seed_pool == NULL) {
if (drbg->secure)
OPENSSL_secure_clear_free(out, outlen);
else
OPENSSL_clear_free(out, outlen);
}
}
/*
* Generate additional data that can be used for the drbg. The data does
* not need to contain entropy, but it's useful if it contains at least
* some bits that are unpredictable.
*
* Returns 0 on failure.
*
* On success it allocates a buffer at |*pout| and returns the length of
* the data. The buffer should get freed using OPENSSL_secure_clear_free().
*/
size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)
{
size_t ret = 0;
if (rand_pool_add_additional_data(pool) == 0)
goto err;
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
err:
return ret;
}
void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
{
rand_pool_reattach(pool, out);
}
#ifndef FIPS_MODE
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;
}
/* TODO(3.0): Do we need to handle this somehow in the FIPS module? */
/*
* RAND_close_seed_files() ensures that any seed file descriptors are
* closed after use.
*/
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)
{
int ret = 0;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth == RAND_OpenSSL()) {
/* fill random pool and seed the master DRBG */
RAND_DRBG *drbg = RAND_DRBG_get0_master();
if (drbg == NULL)
return 0;
rand_drbg_lock(drbg);
ret = rand_drbg_restart(drbg, NULL, 0, 0);
rand_drbg_unlock(drbg);
return ret;
} else {
RAND_POOL *pool = NULL;
/* fill random pool and seed the current legacy RNG */
pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
(RAND_DRBG_STRENGTH + 7) / 8,
RAND_POOL_MAX_LENGTH);
if (pool == NULL)
return 0;
if (rand_pool_acquire_entropy(pool) == 0)
goto err;
if (meth->add == NULL
|| meth->add(rand_pool_buffer(pool),
rand_pool_length(pool),
(rand_pool_entropy(pool) / 8.0)) == 0)
goto err;
ret = 1;
err:
rand_pool_free(pool);
}
return ret;
}
#endif /* FIPS_MODE */
/*
* Allocate memory and initialize a new random pool
*/
RAND_POOL *rand_pool_new(int entropy_requested, int secure,
size_t min_len, size_t max_len)
{
RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
size_t min_alloc_size = RAND_POOL_MIN_ALLOCATION(secure);
if (pool == NULL) {
RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
pool->min_len = min_len;
pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
RAND_POOL_MAX_LENGTH : max_len;
pool->alloc_len = min_len < min_alloc_size ? min_alloc_size : min_len;
if (pool->alloc_len > pool->max_len)
pool->alloc_len = pool->max_len;
if (secure)
pool->buffer = OPENSSL_secure_zalloc(pool->alloc_len);
else
pool->buffer = OPENSSL_zalloc(pool->alloc_len);
if (pool->buffer == NULL) {
RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
goto err;
}
pool->entropy_requested = entropy_requested;
pool->secure = secure;
return pool;
err:
OPENSSL_free(pool);
return NULL;
}
/*
* Attach new random pool to the given buffer
*
* This function is intended to be used only for feeding random data
* provided by RAND_add() and RAND_seed() into the <master> DRBG.
*/
RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
size_t entropy)
{
RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
if (pool == NULL) {
RANDerr(RAND_F_RAND_POOL_ATTACH, ERR_R_MALLOC_FAILURE);
return NULL;
}
/*
* The const needs to be cast away, but attached buffers will not be
* modified (in contrary to allocated buffers which are zeroed and
* freed in the end).
*/
pool->buffer = (unsigned char *) buffer;
pool->len = len;
pool->attached = 1;
pool->min_len = pool->max_len = pool->alloc_len = pool->len;
pool->entropy = entropy;
return pool;
}
/*
* Free |pool|, securely erasing its buffer.
*/
void rand_pool_free(RAND_POOL *pool)
{
if (pool == NULL)
return;
/*
* Although it would be advisable from a cryptographical viewpoint,
* we are not allowed to clear attached buffers, since they are passed
* to rand_pool_attach() as `const unsigned char*`.
* (see corresponding comment in rand_pool_attach()).
*/
if (!pool->attached) {
if (pool->secure)
OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
else
OPENSSL_clear_free(pool->buffer, pool->alloc_len);
}
OPENSSL_free(pool);
}
/*
* Return the |pool|'s buffer to the caller (readonly).
*/
const unsigned char *rand_pool_buffer(RAND_POOL *pool)
{
return pool->buffer;
}
/*
* Return the |pool|'s entropy to the caller.
*/
size_t rand_pool_entropy(RAND_POOL *pool)
{
return pool->entropy;
}
/*
* Return the |pool|'s buffer length to the caller.
*/
size_t rand_pool_length(RAND_POOL *pool)
{
return pool->len;
}
/*
* Detach the |pool| buffer and return it to the caller.
* It's the responsibility of the caller to free the buffer
* using OPENSSL_secure_clear_free() or to re-attach it
* again to the pool using rand_pool_reattach().
*/
unsigned char *rand_pool_detach(RAND_POOL *pool)
{
unsigned char *ret = pool->buffer;
pool->buffer = NULL;
pool->entropy = 0;
return ret;
}
/*
* Re-attach the |pool| buffer. It is only allowed to pass
* the |buffer| which was previously detached from the same pool.
*/
void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer)
{
pool->buffer = buffer;
OPENSSL_cleanse(pool->buffer, pool->len);
pool->len = 0;
}
/*
* If |entropy_factor| bits contain 1 bit of entropy, how many bytes does one
* need to obtain at least |bits| bits of entropy?
*/
#define ENTROPY_TO_BYTES(bits, entropy_factor) \
(((bits) * (entropy_factor) + 7) / 8)
/*
* Checks whether the |pool|'s entropy is available to the caller.
* This is the case when entropy count and buffer length are high enough.
* Returns
*
* |entropy| if the entropy count and buffer size is large enough
* 0 otherwise
*/
size_t rand_pool_entropy_available(RAND_POOL *pool)
{
if (pool->entropy < pool->entropy_requested)
return 0;
if (pool->len < pool->min_len)
return 0;
return pool->entropy;
}
/*
* Returns the (remaining) amount of entropy needed to fill
* the random pool.
*/
size_t rand_pool_entropy_needed(RAND_POOL *pool)
{
if (pool->entropy < pool->entropy_requested)
return pool->entropy_requested - pool->entropy;
return 0;
}
/* Increase the allocation size -- not usable for an attached pool */
static int rand_pool_grow(RAND_POOL *pool, size_t len)
{
if (len > pool->alloc_len - pool->len) {
unsigned char *p;
const size_t limit = pool->max_len / 2;
size_t newlen = pool->alloc_len;
if (pool->attached || len > pool->max_len - pool->len) {
RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_INTERNAL_ERROR);
return 0;
}
do
newlen = newlen < limit ? newlen * 2 : pool->max_len;
while (len > newlen - pool->len);
if (pool->secure)
p = OPENSSL_secure_zalloc(newlen);
else
p = OPENSSL_zalloc(newlen);
if (p == NULL) {
RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_MALLOC_FAILURE);
return 0;
}
memcpy(p, pool->buffer, pool->len);
if (pool->secure)
OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
else
OPENSSL_clear_free(pool->buffer, pool->alloc_len);
pool->buffer = p;
pool->alloc_len = newlen;
}
return 1;
}
/*
* Returns the number of bytes needed to fill the pool, assuming
* the input has 1 / |entropy_factor| entropy bits per data bit.
* In case of an error, 0 is returned.
*/
size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
{
size_t bytes_needed;
size_t entropy_needed = rand_pool_entropy_needed(pool);
if (entropy_factor < 1) {
RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
return 0;
}
bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_factor);
if (bytes_needed > pool->max_len - pool->len) {
/* not enough space left */
RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW);
return 0;
}
if (pool->len < pool->min_len &&
bytes_needed < pool->min_len - pool->len)
/* to meet the min_len requirement */
bytes_needed = pool->min_len - pool->len;
/*
* Make sure the buffer is large enough for the requested amount
* of data. This guarantees that existing code patterns where
* rand_pool_add_begin, rand_pool_add_end or rand_pool_add
* are used to collect entropy data without any error handling
* whatsoever, continue to be valid.
* Furthermore if the allocation here fails once, make sure that
* we don't fall back to a less secure or even blocking random source,
* as that could happen by the existing code patterns.
* This is not a concern for additional data, therefore that
* is not needed if rand_pool_grow fails in other places.
*/
if (!rand_pool_grow(pool, bytes_needed)) {
/* persistent error for this pool */
pool->max_len = pool->len = 0;
return 0;
}
return bytes_needed;
}
/* Returns the remaining number of bytes available */
size_t rand_pool_bytes_remaining(RAND_POOL *pool)
{
return pool->max_len - pool->len;
}
/*
* Add random bytes to the random pool.
*
* It is expected that the |buffer| contains |len| bytes of
* random input which contains at least |entropy| bits of
* randomness.
*
* Returns 1 if the added amount is adequate, otherwise 0
*/
int rand_pool_add(RAND_POOL *pool,
const unsigned char *buffer, size_t len, size_t entropy)
{
if (len > pool->max_len - pool->len) {
RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
return 0;
}
if (pool->buffer == NULL) {
RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
return 0;
}
if (len > 0) {
/*
* This is to protect us from accidentally passing the buffer
* returned from rand_pool_add_begin.
* The check for alloc_len makes sure we do not compare the
* address of the end of the allocated memory to something
* different, since that comparison would have an
* indeterminate result.
*/
if (pool->alloc_len > pool->len && pool->buffer + pool->len == buffer) {
RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
return 0;
}
/*
* We have that only for cases when a pool is used to collect
* additional data.
* For entropy data, as long as the allocation request stays within
* the limits given by rand_pool_bytes_needed this rand_pool_grow
* below is guaranteed to succeed, thus no allocation happens.
*/
if (!rand_pool_grow(pool, len))
return 0;
memcpy(pool->buffer + pool->len, buffer, len);
pool->len += len;
pool->entropy += entropy;
}
return 1;
}
/*
* Start to add random bytes to the random pool in-place.
*
* Reserves the next |len| bytes for adding random bytes in-place
* and returns a pointer to the buffer.
* The caller is allowed to copy up to |len| bytes into the buffer.
* If |len| == 0 this is considered a no-op and a NULL pointer
* is returned without producing an error message.
*
* After updating the buffer, rand_pool_add_end() needs to be called
* to finish the udpate operation (see next comment).
*/
unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len)
{
if (len == 0)
return NULL;
if (len > pool->max_len - pool->len) {
RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
return NULL;
}
if (pool->buffer == NULL) {
RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, ERR_R_INTERNAL_ERROR);
return NULL;
}
/*
* As long as the allocation request stays within the limits given
* by rand_pool_bytes_needed this rand_pool_grow below is guaranteed
* to succeed, thus no allocation happens.
* We have that only for cases when a pool is used to collect
* additional data. Then the buffer might need to grow here,
* and of course the caller is responsible to check the return
* value of this function.
*/
if (!rand_pool_grow(pool, len))
return NULL;
return pool->buffer + pool->len;
}
/*
* Finish to add random bytes to the random pool in-place.
*
* Finishes an in-place update of the random pool started by
* rand_pool_add_begin() (see previous comment).
* It is expected that |len| bytes of random input have been added
* to the buffer which contain at least |entropy| bits of randomness.
* It is allowed to add less bytes than originally reserved.
*/
int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy)
{
if (len > pool->alloc_len - pool->len) {
RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
return 0;
}
if (len > 0) {
pool->len += len;
pool->entropy += entropy;
}
return 1;
}
#ifndef FIPS_MODE
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;
}
#endif
const RAND_METHOD *RAND_get_rand_method(void)
{
#ifdef FIPS_MODE
return NULL;
#else
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;
#endif
}
#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
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->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->add != NULL)
meth->add(buf, num, randomness);
}
/*
* 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(OPENSSL_CTX *ctx, unsigned char *buf, int num)
{
RAND_DRBG *drbg;
int ret;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth != RAND_OpenSSL())
return meth->bytes(buf, num);
drbg = OPENSSL_CTX_get0_private_drbg(ctx);
if (drbg == NULL)
return 0;
ret = RAND_DRBG_bytes(drbg, buf, num);
return ret;
}
int RAND_priv_bytes(unsigned char *buf, int num)
{
return rand_priv_bytes_ex(NULL, buf, num);
}
int rand_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
{
RAND_DRBG *drbg;
int ret;
const RAND_METHOD *meth = RAND_get_rand_method();
if (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;
}
drbg = OPENSSL_CTX_get0_public_drbg(ctx);
if (drbg == NULL)
return 0;
ret = RAND_DRBG_bytes(drbg, buf, num);
return ret;
}
int RAND_bytes(unsigned char *buf, int num)
{
return rand_bytes_ex(NULL, buf, num);
}
#if !OPENSSL_API_1_1_0 && !defined(FIPS_MODE)
int RAND_pseudo_bytes(unsigned char *buf, int num)
{
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth->pseudorand != NULL)
return meth->pseudorand(buf, num);
return -1;
}
#endif
int RAND_status(void)
{
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth->status != NULL)
return meth->status();
return 0;
}