mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-27 00:28:10 +00:00
82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/**
|
|
* Copyright (c) 2013-2014 Tomas Dzetkulic
|
|
* Copyright (c) 2013-2014 Pavol Rusnak
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the "Software"),
|
|
* to deal in the Software without restriction, including without limitation
|
|
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
|
* and/or sell copies of the Software, and to permit persons to whom the
|
|
* Software is furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included
|
|
* in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
|
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
|
|
* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
|
|
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
|
* OTHER DEALINGS IN THE SOFTWARE.
|
|
*/
|
|
|
|
#include "rand.h"
|
|
|
|
#ifndef RAND_PLATFORM_INDEPENDENT
|
|
|
|
#pragma message( \
|
|
"NOT SUITABLE FOR PRODUCTION USE! Replace random32() function with your own secure code.")
|
|
|
|
// The following code is not supposed to be used in a production environment.
|
|
// It's included only to make the library testable.
|
|
// The message above tries to prevent any accidental use outside of the test
|
|
// environment.
|
|
//
|
|
// You are supposed to replace the random8() and random32() function with your
|
|
// own secure code. There is also a possibility to replace the random_buffer()
|
|
// function as it is defined as a weak symbol.
|
|
|
|
static uint32_t seed = 0;
|
|
|
|
void random_reseed(const uint32_t value) { seed = value; }
|
|
|
|
uint32_t random32(void) {
|
|
// Linear congruential generator from Numerical Recipes
|
|
// https://en.wikipedia.org/wiki/Linear_congruential_generator
|
|
seed = 1664525 * seed + 1013904223;
|
|
return seed;
|
|
}
|
|
|
|
#endif /* RAND_PLATFORM_INDEPENDENT */
|
|
|
|
//
|
|
// The following code is platform independent
|
|
//
|
|
|
|
void __attribute__((weak)) random_buffer(uint8_t *buf, size_t len) {
|
|
uint32_t r = 0;
|
|
for (size_t i = 0; i < len; i++) {
|
|
if (i % 4 == 0) {
|
|
r = random32();
|
|
}
|
|
buf[i] = (r >> ((i % 4) * 8)) & 0xFF;
|
|
}
|
|
}
|
|
|
|
uint32_t random_uniform(uint32_t n) {
|
|
uint32_t x, max = 0xFFFFFFFF - (0xFFFFFFFF % n);
|
|
while ((x = random32()) >= max)
|
|
;
|
|
return x / (max / n);
|
|
}
|
|
|
|
void random_permute(char *str, size_t len) {
|
|
for (int i = len - 1; i >= 1; i--) {
|
|
int j = random_uniform(i + 1);
|
|
char t = str[j];
|
|
str[j] = str[i];
|
|
str[i] = t;
|
|
}
|
|
}
|