src/libstrongswan/plugins/random/random_plugin.c

   1 /*
   2  * Copyright (C) 2008 Martin Willi
   3  * Hochschule fuer Technik Rapperswil
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 #include "random_plugin.h"
  17
  18 #include <unistd.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <fcntl.h>
  22 #include <errno.h>
  23
  24 #include <library.h>
  25 #include <utils/debug.h>
  26 #include "random_rng.h"
  27
  28 #ifndef DEV_RANDOM
  29 # define DEV_RANDOM "/dev/random"
  30 #endif
  31
  32 #ifndef DEV_URANDOM
  33 # define DEV_URANDOM "/dev/urandom"
  34 #endif
  35
  36 typedef struct private_random_plugin_t private_random_plugin_t;
  37
  38 /**
  39  * private data of random_plugin
  40  */
  41 struct private_random_plugin_t {
  42
  43         /**
  44          * public functions
  45          */
  46         random_plugin_t public;
  47 };
  48
  49 /** /dev/random file descriptor */
  50 static int dev_random = -1;
  51 /** /dev/urandom file descriptor */
  52 static int dev_urandom = -1;
  53
  54 /** Is strong randomness equivalent to true randomness? */
  55 static bool strong_equals_true = FALSE;
  56
  57 /**
  58  * See header.
  59  */
  60 int random_plugin_get_dev_random()
  61 {
  62         return dev_random;
  63 }
  64
  65 /**
  66  * See header.
  67  */
  68 int random_plugin_get_dev_urandom()
  69 {
  70         return dev_urandom;
  71 }
  72
  73 /**
  74  * See header.
  75  */
  76 bool random_plugin_get_strong_equals_true()
  77 {
  78         return strong_equals_true;
  79 }
  80
  81 /**
  82  * Open a random device file
  83  */
  84 static bool open_dev(char *file, int *fd)
  85 {
  86         *fd = open(file, O_RDONLY);
  87         if (*fd == -1)
  88         {
  89                 DBG1(DBG_LIB, "opening \"%s\" failed: %s", file, strerror(errno));
  90                 return FALSE;
  91         }
  92         return TRUE;
  93 }
  94
  95 METHOD(plugin_t, get_name, char*,
  96         private_random_plugin_t *this)
  97 {
  98         return "random";
  99 }
 100
 101 METHOD(plugin_t, get_features, int,
 102         private_random_plugin_t *this, plugin_feature_t *features[])
 103 {
 104         static plugin_feature_t f[] = {
 105                 PLUGIN_REGISTER(RNG, random_rng_create),
 106                         PLUGIN_PROVIDE(RNG, RNG_STRONG),
 107                         PLUGIN_PROVIDE(RNG, RNG_TRUE),
 108         };
 109         *features = f;
 110         return countof(f);
 111 }
 112
 113 METHOD(plugin_t, destroy, void,
 114         private_random_plugin_t *this)
 115 {
 116         if (dev_random != -1)
 117         {
 118                 close(dev_random);
 119         }
 120         if (dev_urandom != -1)
 121         {
 122                 close(dev_urandom);
 123         }
 124         free(this);
 125 }
 126
 127 /*
 128  * see header file
 129  */
 130 plugin_t *random_plugin_create()
 131 {
 132         private_random_plugin_t *this;
 133         char *urandom_file, *random_file;
 134
 135         INIT(this,
 136                 .public = {
 137                         .plugin = {
 138                                 .get_name = _get_name,
 139                                 .get_features = _get_features,
 140                                 .destroy = _destroy,
 141                         },
 142                 },
 143         );
 144
 145         strong_equals_true = lib->settings->get_bool(lib->settings,
 146                                                 "%s.plugins.random.strong_equals_true", FALSE, lib->ns);
 147         urandom_file = lib->settings->get_str(lib->settings,
 148                                                 "%s.plugins.random.urandom", DEV_URANDOM, lib->ns);
 149         random_file = lib->settings->get_str(lib->settings,
 150                                                 "%s.plugins.random.random", DEV_RANDOM, lib->ns);
 151         if (!open_dev(urandom_file, &dev_urandom) ||
 152                 !open_dev(random_file, &dev_random))
 153         {
 154                 destroy(this);
 155                 return NULL;
 156         }
 157
 158         return &this->public.plugin;
 159 }
 160