mirror of https://github.com/openssl/openssl.git
68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
/*
|
|
* Copyright 2021 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 "internal/cryptlib.h"
|
|
#include <openssl/opensslconf.h>
|
|
#include "crypto/rand_pool.h"
|
|
#include "prov/seeding.h"
|
|
|
|
|
|
#ifdef OPENSSL_RAND_SEED_RDCPU
|
|
#include "crypto/arm_arch.h"
|
|
|
|
size_t OPENSSL_rndrrs_bytes(unsigned char *buf, size_t len);
|
|
|
|
static size_t get_hardware_random_value(unsigned char *buf, size_t len);
|
|
|
|
/*
|
|
* Acquire entropy using Arm-specific cpu instructions
|
|
*
|
|
* Uses the RNDRRS instruction. RNDR is never needed since
|
|
* RNDRRS will always be available if RNDR is an available
|
|
* instruction.
|
|
*
|
|
* Returns the total entropy count, if it exceeds the requested
|
|
* entropy count. Otherwise, returns an entropy count of 0.
|
|
*/
|
|
size_t ossl_prov_acquire_entropy_from_cpu(RAND_POOL *pool)
|
|
{
|
|
size_t bytes_needed;
|
|
unsigned char *buffer;
|
|
|
|
bytes_needed = ossl_rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
|
|
if (bytes_needed > 0) {
|
|
buffer = ossl_rand_pool_add_begin(pool, bytes_needed);
|
|
|
|
if (buffer != NULL) {
|
|
if (get_hardware_random_value(buffer, bytes_needed) == bytes_needed)
|
|
ossl_rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
|
|
else
|
|
ossl_rand_pool_add_end(pool, 0, 0);
|
|
}
|
|
}
|
|
|
|
return ossl_rand_pool_entropy_available(pool);
|
|
}
|
|
|
|
static size_t get_hardware_random_value(unsigned char *buf, size_t len)
|
|
{
|
|
/* Always use RNDRRS or nothing */
|
|
if (OPENSSL_armcap_P & ARMV8_RNG) {
|
|
if (OPENSSL_rndrrs_bytes(buf, len) != len)
|
|
return 0;
|
|
} else {
|
|
return 0;
|
|
}
|
|
return len;
|
|
}
|
|
|
|
#else
|
|
NON_EMPTY_TRANSLATION_UNIT
|
|
#endif /* OPENSSL_RAND_SEED_RDCPU */
|