Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170103-1' into staging
[qemu.git] / crypto / pbkdf.c
1 /*
2 * QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
3 *
4 * Copyright (c) 2015-2016 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "qapi/error.h"
23 #include "crypto/pbkdf.h"
24 #ifndef _WIN32
25 #include <sys/resource.h>
26 #endif
27
28
29 static int qcrypto_pbkdf2_get_thread_cpu(unsigned long long *val_ms,
30 Error **errp)
31 {
32 #ifdef _WIN32
33 FILETIME creation_time, exit_time, kernel_time, user_time;
34 ULARGE_INTEGER thread_time;
35
36 if (!GetThreadTimes(GetCurrentThread(), &creation_time, &exit_time,
37 &kernel_time, &user_time)) {
38 error_setg(errp, "Unable to get thread CPU usage");
39 return -1;
40 }
41
42 thread_time.LowPart = user_time.dwLowDateTime;
43 thread_time.HighPart = user_time.dwHighDateTime;
44
45 /* QuadPart is units of 100ns and we want ms as unit */
46 *val_ms = thread_time.QuadPart / 10000ll;
47 return 0;
48 #elif defined(RUSAGE_THREAD)
49 struct rusage ru;
50 if (getrusage(RUSAGE_THREAD, &ru) < 0) {
51 error_setg_errno(errp, errno, "Unable to get thread CPU usage");
52 return -1;
53 }
54
55 *val_ms = ((ru.ru_utime.tv_sec * 1000ll) +
56 (ru.ru_utime.tv_usec / 1000));
57 return 0;
58 #else
59 *val_ms = 0;
60 error_setg(errp, "Unable to calculate thread CPU usage on this platform");
61 return -1;
62 #endif
63 }
64
65 uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash,
66 const uint8_t *key, size_t nkey,
67 const uint8_t *salt, size_t nsalt,
68 size_t nout,
69 Error **errp)
70 {
71 uint64_t ret = -1;
72 uint8_t *out;
73 uint64_t iterations = (1 << 15);
74 unsigned long long delta_ms, start_ms, end_ms;
75
76 out = g_new(uint8_t, nout);
77
78 while (1) {
79 if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) {
80 goto cleanup;
81 }
82 if (qcrypto_pbkdf2(hash,
83 key, nkey,
84 salt, nsalt,
85 iterations,
86 out, nout,
87 errp) < 0) {
88 goto cleanup;
89 }
90 if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) {
91 goto cleanup;
92 }
93
94 delta_ms = end_ms - start_ms;
95
96 if (delta_ms > 500) {
97 break;
98 } else if (delta_ms < 100) {
99 iterations = iterations * 10;
100 } else {
101 iterations = (iterations * 1000 / delta_ms);
102 }
103 }
104
105 iterations = iterations * 1000 / delta_ms;
106
107 ret = iterations;
108
109 cleanup:
110 memset(out, 0, nout);
111 g_free(out);
112 return ret;
113 }