lib/hcrypto/rand-w32.c

   1 /*
   2  * Copyright (c) 2006 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35 #include <roken.h>
  36
  37 #include <wincrypt.h>
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <rand.h>
  42 #include <heim_threads.h>
  43
  44 #include "randi.h"
  45
  46 volatile static HCRYPTPROV g_cryptprovider = 0;
  47
  48 static HCRYPTPROV
  49 _hc_CryptProvider(void)
  50 {
  51     BOOL rv;
  52     HCRYPTPROV cryptprovider = 0;
  53
  54     if (g_cryptprovider != 0)
  55         return g_cryptprovider;
  56
  57     rv = CryptAcquireContext(&cryptprovider, NULL,
  58                               MS_ENHANCED_PROV, PROV_RSA_FULL,
  59                               CRYPT_VERIFYCONTEXT);
  60
  61     if (GetLastError() == NTE_BAD_KEYSET) {
  62         rv = CryptAcquireContext(&cryptprovider, NULL,
  63                                  MS_ENHANCED_PROV, PROV_RSA_FULL,
  64                                  CRYPT_NEWKEYSET);
  65     }
  66
  67     if (rv) {
  68         /* try the default provider */
  69         rv = CryptAcquireContext(&cryptprovider, NULL, 0, PROV_RSA_FULL,
  70                                  CRYPT_VERIFYCONTEXT);
  71
  72         if (GetLastError() == NTE_BAD_KEYSET) {
  73             rv = CryptAcquireContext(&cryptprovider, NULL,
  74                                      MS_ENHANCED_PROV, PROV_RSA_FULL,
  75                                      CRYPT_NEWKEYSET);
  76         }
  77     }
  78
  79     if (rv) {
  80         /* try just a default random number generator */
  81         rv = CryptAcquireContext(&cryptprovider, NULL, 0, PROV_RNG,
  82                                  CRYPT_VERIFYCONTEXT);
  83     }
  84
  85     if (rv &&
  86         InterlockedCompareExchangePointer((PVOID *) &g_cryptprovider,
  87                                           (PVOID) cryptprovider, 0) != 0) {
  88
  89         CryptReleaseContext(cryptprovider, 0);
  90         cryptprovider = g_cryptprovider;
  91     }
  92
  93     return cryptprovider;
  94 }
  95
  96 /*
  97  *
  98  */
  99
 100
 101 static void
 102 w32crypto_seed(const void *indata, int size)
 103 {
 104 }
 105
 106
 107 static int
 108 w32crypto_bytes(unsigned char *outdata, int size)
 109 {
 110     if (CryptGenRandom(_hc_CryptProvider(), size, outdata))
 111         return 1;
 112     return 0;
 113 }
 114
 115 static void
 116 w32crypto_cleanup(void)
 117 {
 118     HCRYPTPROV cryptprovider;
 119
 120     if (InterlockedCompareExchangePointer((PVOID *) &cryptprovider,
 121                                           0, (PVOID) g_cryptprovider) == 0) {
 122         CryptReleaseContext(cryptprovider, 0);
 123     }
 124 }
 125
 126 static void
 127 w32crypto_add(const void *indata, int size, double entropi)
 128 {
 129 }
 130
 131 static int
 132 w32crypto_status(void)
 133 {
 134     if (_hc_CryptProvider() == 0)
 135         return 0;
 136     return 1;
 137 }
 138
 139 const RAND_METHOD hc_rand_w32crypto_method = {
 140     w32crypto_seed,
 141     w32crypto_bytes,
 142     w32crypto_cleanup,
 143     w32crypto_add,
 144     w32crypto_bytes,
 145     w32crypto_status
 146 };
 147
 148 const RAND_METHOD *
 149 RAND_w32crypto_method(void)
 150 {
 151     return &hc_rand_w32crypto_method;
 152 }