66 lines
1.4 KiB
C
66 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2015 Cedric Hnyda <ced.hnyda@gmail.com>
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*
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* Calls getrandom(2), checks that the buffer is filled with random bytes
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* and expects success.
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*/
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#include "lapi/getrandom.h"
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#include "lapi/syscalls.h"
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#include "tst_test.h"
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#define PROC_ENTROPY_AVAIL "/proc/sys/kernel/random/entropy_avail"
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static int modes[] = { 0, GRND_RANDOM, GRND_NONBLOCK,
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GRND_RANDOM | GRND_NONBLOCK };
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static int check_content(unsigned char *buf, int nb)
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{
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int table[256];
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int i, index, max;
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memset(table, 0, sizeof(table));
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max = 6 + nb * 0.2;
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for (i = 0; i < nb; i++) {
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index = buf[i];
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table[index]++;
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}
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for (i = 0; i < nb; i++) {
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if (max > 0 && table[i] > max)
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return 0;
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}
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return 1;
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}
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static void verify_getrandom(unsigned int n)
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{
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unsigned char buf[256];
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int bufsize = 64, entropy_avail;
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if (access(PROC_ENTROPY_AVAIL, F_OK) == 0) {
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SAFE_FILE_SCANF(PROC_ENTROPY_AVAIL, "%d", &entropy_avail);
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if (entropy_avail > 256)
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bufsize = sizeof(buf);
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}
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memset(buf, 0, sizeof(buf));
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do {
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TEST(tst_syscall(__NR_getrandom, buf, bufsize, modes[n]));
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} while ((modes[n] & GRND_NONBLOCK) && TST_RET == -1
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&& TST_ERR == EAGAIN);
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if (!check_content(buf, TST_RET))
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tst_res(TFAIL | TTERRNO, "getrandom failed");
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else
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tst_res(TPASS, "getrandom returned %ld", TST_RET);
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}
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static struct tst_test test = {
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.tcnt = ARRAY_SIZE(modes),
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.test = verify_getrandom,
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};
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