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bf98afc75e
When the user creates a LUKS-encrypted qcow2 image using the qemu-img program, the passphrase is hashed using PBKDF2 with a dynamic number of iterations. The number of iterations is determined by measuring thread cpu time usage, such that it takes approximately 2 seconds to compute the hash. Because Darwin doesn't implement getrusage(RUSAGE_THREAD), we get an error message: > qemu-img: test.qcow2: Unable to calculate thread CPU usage on this platform for this command: > qemu-img create --object secret,id=key,data=1234 -f qcow2 -o 'encrypt.format=luks,encrypt.key-secret=key' test.qcow2 100M This patch implements qcrypto_pbkdf2_get_thread_cpu() for Darwin so that the above command works. Signed-off-by: Jungmin Park <pjm0616@gmail.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
134 lines
4.0 KiB
C
134 lines
4.0 KiB
C
/*
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* QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
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*
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* Copyright (c) 2015-2016 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "crypto/pbkdf.h"
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#ifndef _WIN32
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#include <sys/resource.h>
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#endif
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#ifdef CONFIG_DARWIN
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#include <mach/mach_init.h>
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#include <mach/thread_act.h>
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#include <mach/mach_port.h>
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#endif
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static int qcrypto_pbkdf2_get_thread_cpu(unsigned long long *val_ms,
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Error **errp)
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{
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#ifdef _WIN32
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FILETIME creation_time, exit_time, kernel_time, user_time;
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ULARGE_INTEGER thread_time;
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if (!GetThreadTimes(GetCurrentThread(), &creation_time, &exit_time,
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&kernel_time, &user_time)) {
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error_setg(errp, "Unable to get thread CPU usage");
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return -1;
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}
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thread_time.LowPart = user_time.dwLowDateTime;
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thread_time.HighPart = user_time.dwHighDateTime;
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/* QuadPart is units of 100ns and we want ms as unit */
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*val_ms = thread_time.QuadPart / 10000ll;
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return 0;
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#elif defined(CONFIG_DARWIN)
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mach_port_t thread;
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kern_return_t kr;
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mach_msg_type_number_t count;
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thread_basic_info_data_t info;
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thread = mach_thread_self();
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count = THREAD_BASIC_INFO_COUNT;
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kr = thread_info(thread, THREAD_BASIC_INFO, (thread_info_t)&info, &count);
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mach_port_deallocate(mach_task_self(), thread);
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if (kr != KERN_SUCCESS || (info.flags & TH_FLAGS_IDLE) != 0) {
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error_setg_errno(errp, errno, "Unable to get thread CPU usage");
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return -1;
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}
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*val_ms = ((info.user_time.seconds * 1000ll) +
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(info.user_time.microseconds / 1000));
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return 0;
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#elif defined(RUSAGE_THREAD)
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struct rusage ru;
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if (getrusage(RUSAGE_THREAD, &ru) < 0) {
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error_setg_errno(errp, errno, "Unable to get thread CPU usage");
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return -1;
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}
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*val_ms = ((ru.ru_utime.tv_sec * 1000ll) +
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(ru.ru_utime.tv_usec / 1000));
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return 0;
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#else
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*val_ms = 0;
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error_setg(errp, "Unable to calculate thread CPU usage on this platform");
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return -1;
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#endif
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}
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uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash,
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const uint8_t *key, size_t nkey,
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const uint8_t *salt, size_t nsalt,
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size_t nout,
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Error **errp)
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{
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uint64_t ret = -1;
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g_autofree uint8_t *out = g_new(uint8_t, nout);
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uint64_t iterations = (1 << 15);
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unsigned long long delta_ms, start_ms, end_ms;
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while (1) {
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if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) {
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goto cleanup;
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}
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if (qcrypto_pbkdf2(hash,
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key, nkey,
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salt, nsalt,
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iterations,
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out, nout,
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errp) < 0) {
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goto cleanup;
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}
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if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) {
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goto cleanup;
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}
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delta_ms = end_ms - start_ms;
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if (delta_ms > 500) {
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break;
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} else if (delta_ms < 100) {
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iterations = iterations * 10;
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} else {
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iterations = (iterations * 1000 / delta_ms);
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}
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}
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iterations = iterations * 1000 / delta_ms;
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ret = iterations;
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cleanup:
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memset(out, 0, nout);
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return ret;
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}
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