62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
#include <assert.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "hash.h"
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#include "random.h"
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static void generate_system_random_bytes(size_t n, void *result) {
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int fd;
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if ((fd = open("/dev/urandom", O_RDONLY | O_NOCTTY | O_CLOEXEC)) < 0) {
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err(EXIT_FAILURE, "open /dev/urandom");
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}
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for (;;) {
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ssize_t res = read(fd, result, n);
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if ((size_t) res == n) {
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break;
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}
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if (res < 0) {
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if (errno != EINTR) {
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err(EXIT_FAILURE, "read /dev/urandom");
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}
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} else if (res == 0) {
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errx(EXIT_FAILURE, "read /dev/urandom: end of file");
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} else {
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result = padd(result, (size_t) res);
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n -= (size_t) res;
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}
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}
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if (close(fd) < 0) {
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err(EXIT_FAILURE, "close /dev/urandom");
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}
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}
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static struct keccak_state state;
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void init_random(void) {
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generate_system_random_bytes(32, &state);
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}
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void generate_random_bytes(size_t n, void *result) {
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if (n == 0) {
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return;
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}
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for (;;) {
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keccak_permutation(&state);
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if (n <= HASH_DATA_AREA) {
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memcpy(result, &state, n);
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return;
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} else {
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memcpy(result, &state, HASH_DATA_AREA);
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result = padd(result, HASH_DATA_AREA);
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n -= HASH_DATA_AREA;
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}
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}
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} |