mirror of
https://github.com/trezor/trezor-firmware.git
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80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/**
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* Copyright (c) 2013-2014 Tomas Dzetkulic
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* Copyright (c) 2013-2014 Pavol Rusnak
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
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* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <stdio.h>
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#include <assert.h>
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#include "rand.h"
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static FILE *frand = NULL;
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int finalize_rand(void)
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{
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if (!frand) return 0;
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int err = fclose(frand);
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frand = NULL;
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return err;
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}
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uint32_t random32(void)
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{
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uint32_t r;
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size_t len = sizeof(r);
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if (!frand) {
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frand = fopen("/dev/urandom", "r");
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}
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size_t len_read = fread(&r, 1, len, frand);
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(void)len_read;
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assert(len_read == len);
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return r;
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}
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uint32_t random_uniform(uint32_t n)
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{
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uint32_t x, max = 0xFFFFFFFF - (0xFFFFFFFF % n);
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while ((x = random32()) >= max);
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return x / (max / n);
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}
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void random_buffer(uint8_t *buf, size_t len)
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{
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if (!frand) {
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frand = fopen("/dev/urandom", "r");
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}
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size_t len_read = fread(buf, 1, len, frand);
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(void)len_read;
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assert(len_read == len);
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}
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void random_permute(char *str, size_t len)
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{
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int i, j;
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char t;
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for (i = len - 1; i >= 1; i--) {
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j = random_uniform(i + 1);
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t = str[j];
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str[j] = str[i];
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str[i] = t;
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}
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}
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