lib/crypto_backend/pbkdf_check.c

   1 /*
   2  * PBKDF performance check
   3  * Copyright (C) 2012, Red Hat, Inc. All rights reserved.
   4  * Copyright (C) 2012-2014, Milan Broz
   5  *
   6  * This file 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 file 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 file; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <errno.h>
  22 #include <sys/time.h>
  23 #include <sys/resource.h>
  24 #include "crypto_backend.h"
  25
  26 static long time_ms(struct rusage *start, struct rusage *end)
  27 {
  28         int count_kernel_time = 0;
  29         long ms;
  30
  31         if (crypt_backend_flags() & CRYPT_BACKEND_KERNEL)
  32                 count_kernel_time = 1;
  33
  34         /*
  35          * FIXME: if there is no self usage info, count system time.
  36          * This seem like getrusage() bug in some hypervisors...
  37          */
  38         if (!end->ru_utime.tv_sec && !start->ru_utime.tv_sec &&
  39             !end->ru_utime.tv_usec && !start->ru_utime.tv_usec)
  40                 count_kernel_time = 1;
  41
  42         ms = (end->ru_utime.tv_sec - start->ru_utime.tv_sec) * 1000;
  43         ms += (end->ru_utime.tv_usec - start->ru_utime.tv_usec) / 1000;
  44
  45         if (count_kernel_time) {
  46                 ms += (end->ru_stime.tv_sec - start->ru_stime.tv_sec) * 1000;
  47                 ms += (end->ru_stime.tv_usec - start->ru_stime.tv_usec) / 1000;
  48         }
  49
  50         return ms;
  51 }
  52
  53 /* This code benchmarks PBKDF and returns iterations/second using specified hash */
  54 int crypt_pbkdf_check(const char *kdf, const char *hash,
  55                       const char *password, size_t password_size,
  56                       const char *salt, size_t salt_size,
  57                       uint64_t *iter_secs)
  58 {
  59         struct rusage rstart, rend;
  60         int r = 0, step = 0;
  61         long ms = 0;
  62         char buf;
  63         unsigned int iterations;
  64
  65         if (!kdf || !hash)
  66                 return -EINVAL;
  67
  68         iterations = 1 << 15;
  69         while (ms < 500) {
  70                 if (getrusage(RUSAGE_SELF, &rstart) < 0)
  71                         return -EINVAL;
  72
  73                 r = crypt_pbkdf(kdf, hash, password, password_size, salt,
  74                                 salt_size, &buf, 1, iterations);
  75                 if (r < 0)
  76                         return r;
  77
  78                 if (getrusage(RUSAGE_SELF, &rend) < 0)
  79                         return -EINVAL;
  80
  81                 ms = time_ms(&rstart, &rend);
  82                 if (ms > 500)
  83                         break;
  84
  85                 if (ms <= 62)
  86                         iterations <<= 4;
  87                 else if (ms <= 125)
  88                         iterations <<= 3;
  89                 else if (ms <= 250)
  90                         iterations <<= 2;
  91                 else
  92                         iterations <<= 1;
  93
  94                 if (++step > 10 || !iterations)
  95                         return -EINVAL;
  96         }
  97
  98         if (iter_secs)
  99                 *iter_secs = (iterations * 1000) / ms;
 100         return r;
 101 }