| /* |
| * 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 */ |