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 2.1 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 | g_autofree uint8_t *out = g_new(uint8_t, nout); |
73 | uint64_t iterations = (1 << 15); |
74 | unsigned long long delta_ms, start_ms, end_ms; |
75 | |
76 | while (1) { |
77 | if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) { |
78 | goto cleanup; |
79 | } |
80 | if (qcrypto_pbkdf2(hash, |
81 | key, nkey, |
82 | salt, nsalt, |
83 | iterations, |
84 | out, nout, |
85 | errp) < 0) { |
86 | goto cleanup; |
87 | } |
88 | if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) { |
89 | goto cleanup; |
90 | } |
91 | |
92 | delta_ms = end_ms - start_ms; |
93 | |
94 | if (delta_ms > 500) { |
95 | break; |
96 | } else if (delta_ms < 100) { |
97 | iterations = iterations * 10; |
98 | } else { |
99 | iterations = (iterations * 1000 / delta_ms); |
100 | } |
101 | } |
102 | |
103 | iterations = iterations * 1000 / delta_ms; |
104 | |
105 | ret = iterations; |
106 | |
107 | cleanup: |
108 | memset(out, 0, nout); |
109 | return ret; |
110 | } |
111 | |