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 2.1 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 #ifdef CONFIG_DARWIN
  28 #include <mach/mach_init.h>
  29 #include <mach/thread_act.h>
  30 #include <mach/mach_port.h>
  31 #endif
  32
  33
  34 static int qcrypto_pbkdf2_get_thread_cpu(unsigned long long *val_ms,
  35                                          Error **errp)
  36 {
  37 #ifdef _WIN32
  38     FILETIME creation_time, exit_time, kernel_time, user_time;
  39     ULARGE_INTEGER thread_time;
  40
  41     if (!GetThreadTimes(GetCurrentThread(), &creation_time, &exit_time,
  42                         &kernel_time, &user_time)) {
  43         error_setg(errp, "Unable to get thread CPU usage");
  44         return -1;
  45     }
  46
  47     thread_time.LowPart = user_time.dwLowDateTime;
  48     thread_time.HighPart = user_time.dwHighDateTime;
  49
  50     /* QuadPart is units of 100ns and we want ms as unit */
  51     *val_ms = thread_time.QuadPart / 10000ll;
  52     return 0;
  53 #elif defined(CONFIG_DARWIN)
  54     mach_port_t thread;
  55     kern_return_t kr;
  56     mach_msg_type_number_t count;
  57     thread_basic_info_data_t info;
  58
  59     thread = mach_thread_self();
  60     count = THREAD_BASIC_INFO_COUNT;
  61     kr = thread_info(thread, THREAD_BASIC_INFO, (thread_info_t)&info, &count);
  62     mach_port_deallocate(mach_task_self(), thread);
  63     if (kr != KERN_SUCCESS || (info.flags & TH_FLAGS_IDLE) != 0) {
  64         error_setg_errno(errp, errno, "Unable to get thread CPU usage");
  65         return -1;
  66     }
  67
  68     *val_ms = ((info.user_time.seconds * 1000ll) +
  69                (info.user_time.microseconds / 1000));
  70     return 0;
  71 #elif defined(RUSAGE_THREAD)
  72     struct rusage ru;
  73     if (getrusage(RUSAGE_THREAD, &ru) < 0) {
  74         error_setg_errno(errp, errno, "Unable to get thread CPU usage");
  75         return -1;
  76     }
  77
  78     *val_ms = ((ru.ru_utime.tv_sec * 1000ll) +
  79                (ru.ru_utime.tv_usec / 1000));
  80     return 0;
  81 #else
  82     *val_ms = 0;
  83     error_setg(errp, "Unable to calculate thread CPU usage on this platform");
  84     return -1;
  85 #endif
  86 }
  87
  88 uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash,
  89                                     const uint8_t *key, size_t nkey,
  90                                     const uint8_t *salt, size_t nsalt,
  91                                     size_t nout,
  92                                     Error **errp)
  93 {
  94     uint64_t ret = -1;
  95     g_autofree uint8_t *out = g_new(uint8_t, nout);
  96     uint64_t iterations = (1 << 15);
  97     unsigned long long delta_ms, start_ms, end_ms;
  98
  99     while (1) {
 100         if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) {
 101             goto cleanup;
 102         }
 103         if (qcrypto_pbkdf2(hash,
 104                            key, nkey,
 105                            salt, nsalt,
 106                            iterations,
 107                            out, nout,
 108                            errp) < 0) {
 109             goto cleanup;
 110         }
 111         if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) {
 112             goto cleanup;
 113         }
 114
 115         delta_ms = end_ms - start_ms;
 116
 117         if (delta_ms > 500) {
 118             break;
 119         } else if (delta_ms < 100) {
 120             iterations = iterations * 10;
 121         } else {
 122             iterations = (iterations * 1000 / delta_ms);
 123         }
 124     }
 125
 126     iterations = iterations * 1000 / delta_ms;
 127
 128     ret = iterations;
 129
 130  cleanup:
 131     memset(out, 0, nout);
 132     return ret;
 133 }