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/*
* QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
*
* Copyright (c) 2015-2016 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "crypto/pbkdf.h"
#ifndef _WIN32
#include <sys/resource.h>
#endif
static int qcrypto_pbkdf2_get_thread_cpu(unsigned long long *val_ms,
Error **errp)
{
#ifdef _WIN32
FILETIME creation_time, exit_time, kernel_time, user_time;
ULARGE_INTEGER thread_time;
if (!GetThreadTimes(GetCurrentThread(), &creation_time, &exit_time,
&kernel_time, &user_time)) {
error_setg(errp, "Unable to get thread CPU usage");
return -1;
}
thread_time.LowPart = user_time.dwLowDateTime;
thread_time.HighPart = user_time.dwHighDateTime;
/* QuadPart is units of 100ns and we want ms as unit */
*val_ms = thread_time.QuadPart / 10000ll;
return 0;
#elif defined(RUSAGE_THREAD)
struct rusage ru;
if (getrusage(RUSAGE_THREAD, &ru) < 0) {
error_setg_errno(errp, errno, "Unable to get thread CPU usage");
return -1;
}
*val_ms = ((ru.ru_utime.tv_sec * 1000ll) +
(ru.ru_utime.tv_usec / 1000));
return 0;
#else
*val_ms = 0;
error_setg(errp, "Unable to calculate thread CPU usage on this platform");
return -1;
#endif
}
int qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash,
const uint8_t *key, size_t nkey,
const uint8_t *salt, size_t nsalt,
Error **errp)
{
uint8_t out[32];
long long int iterations = (1 << 15);
unsigned long long delta_ms, start_ms, end_ms;
while (1) {
if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) {
return -1;
}
if (qcrypto_pbkdf2(hash,
key, nkey,
salt, nsalt,
iterations,
out, sizeof(out),
errp) < 0) {
return -1;
}
if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) {
return -1;
}
delta_ms = end_ms - start_ms;
if (delta_ms > 500) {
break;
} else if (delta_ms < 100) {
iterations = iterations * 10;
} else {
iterations = (iterations * 1000 / delta_ms);
}
}
iterations = iterations * 1000 / delta_ms;
if (iterations > INT32_MAX) {
error_setg(errp, "Iterations %lld too large for a 32-bit int",
iterations);
return -1;
}
return iterations;
}
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