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148 lines
4.1 KiB
C
148 lines
4.1 KiB
C
/*
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* Non-physical true random number generator based on timing jitter.
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*
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* Copyright Stephan Mueller <smueller@chronox.de>, 2013 - 2022
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*
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* License
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* =======
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU General Public License, in which case the provisions of the GPL are
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* required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*/
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#ifndef _JITTERENTROPY_BASE_POWER_H
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#define _JITTERENTROPY_BASE_POWER_H
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#include <sched.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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/* taken from http://www.ecrypt.eu.org/ebats/cpucycles.html */
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static inline void jent_get_nstime(uint64_t *out)
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{
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unsigned long high;
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unsigned long low;
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unsigned long newhigh;
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uint64_t result;
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asm volatile(
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"Lcpucycles:mftbu %0;mftb %1;mftbu %2;cmpw %0,%2;bne Lcpucycles"
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: "=r" (high), "=r" (low), "=r" (newhigh)
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);
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result = high;
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result <<= 32;
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result |= low;
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*out = result;
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}
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static inline void *jent_zalloc(size_t len)
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{
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void *tmp = NULL;
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/* we have no secure memory allocation! Hence
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* we do not sed CRYPTO_CPU_JITTERENTROPY_SECURE_MEMORY */
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tmp = malloc(len);
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if(NULL != tmp)
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memset(tmp, 0, len);
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return tmp;
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}
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static inline void jent_zfree(void *ptr, unsigned int len)
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{
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memset(ptr, 0, len);
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free(ptr);
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}
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static inline int jent_fips_enabled(void)
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{
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return 0;
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}
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static inline long jent_ncpu(void)
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{
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/*
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* TODO: return number of available CPUs -
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* this code disables timer thread as only one CPU is "detected".
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*/
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return 1;
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}
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static inline void jent_yield(void)
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{
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sched_yield();
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}
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static inline uint32_t jent_cache_size_roundup(void)
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{
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#ifdef __linux__
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long l1 = sysconf(_SC_LEVEL1_DCACHE_SIZE);
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long l2 = sysconf(_SC_LEVEL2_CACHE_SIZE);
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long l3 = sysconf(_SC_LEVEL3_CACHE_SIZE);
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uint32_t cache_size = 0;
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/* Cache size reported by system */
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if (l1 > 0)
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cache_size += (uint32_t)l1;
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if (l2 > 0)
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cache_size += (uint32_t)l2;
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if (l3 > 0)
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cache_size += (uint32_t)l3;
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/* Force the output_size to be of the form (bounding_power_of_2 - 1). */
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cache_size |= (cache_size >> 1);
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cache_size |= (cache_size >> 2);
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cache_size |= (cache_size >> 4);
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cache_size |= (cache_size >> 8);
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cache_size |= (cache_size >> 16);
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if (cache_size == 0)
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return 0;
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/* Make the output_size the smallest power of 2 strictly greater than cache_size. */
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cache_size++;
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return cache_size;
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#else
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return 0;
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#endif
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}
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/* --- helpers needed in user space -- */
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static inline uint64_t rol64(uint64_t x, int n)
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{
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return ( (x << (n&(64-1))) | (x >> ((64-n)&(64-1))) );
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}
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#endif /* _JITTERENTROPY_BASE_POWER_H */
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