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