/* * Non-physical true random number generator based on timing jitter -- * Linux Kernel Crypto API specific code * * Copyright Stephan Mueller <[email protected]>, 2015 - 2023 * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, and the entire permission notice in its entirety, * including the disclaimer of warranties. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * ALTERNATIVELY, this product may be distributed under the terms of * the GNU General Public License, in which case the provisions of the GPL2 are * required INSTEAD OF the above restrictions. (This clause is * necessary due to a potential bad interaction between the GPL and * the restrictions contained in a BSD-style copyright.) * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. */ #include <crypto/hash.h> #include <crypto/sha3.h> #include <linux/fips.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/time.h> #include <crypto/internal/rng.h> #include "jitterentropy.h" #define JENT_CONDITIONING_HASH … /*************************************************************************** * Helper function ***************************************************************************/ void *jent_kvzalloc(unsigned int len) { … } void jent_kvzfree(void *ptr, unsigned int len) { … } void *jent_zalloc(unsigned int len) { … } void jent_zfree(void *ptr) { … } /* * Obtain a high-resolution time stamp value. The time stamp is used to measure * the execution time of a given code path and its variations. Hence, the time * stamp must have a sufficiently high resolution. * * Note, if the function returns zero because a given architecture does not * implement a high-resolution time stamp, the RNG code's runtime test * will detect it and will not produce output. */ void jent_get_nstime(__u64 *out) { … } int jent_hash_time(void *hash_state, __u64 time, u8 *addtl, unsigned int addtl_len, __u64 hash_loop_cnt, unsigned int stuck) { … } int jent_read_random_block(void *hash_state, char *dst, unsigned int dst_len) { … } /*************************************************************************** * Kernel crypto API interface ***************************************************************************/ struct jitterentropy { … }; static void jent_kcapi_cleanup(struct crypto_tfm *tfm) { … } static int jent_kcapi_init(struct crypto_tfm *tfm) { … } static int jent_kcapi_random(struct crypto_rng *tfm, const u8 *src, unsigned int slen, u8 *rdata, unsigned int dlen) { … } static int jent_kcapi_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) { … } static struct rng_alg jent_alg = …; static int __init jent_mod_init(void) { … } static void __exit jent_mod_exit(void) { … } module_init(…) …; module_exit(jent_mod_exit); MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_ALIAS_CRYPTO(…) …;
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