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 <rand.h>
  40 #include <heim_threads.h>
  41
  42 #include "randi.h"
  43
  44 volatile static HCRYPTPROV g_cryptprovider = NULL;
  45
  46 static HCRYPTPROV
  47 _hc_CryptProvider(void)
  48 {
  49     BOOL rv;
  50     HCRYPTPROV cryptprovider = NULL;
  51
  52     if (g_cryptprovider != NULL)
  53         goto out;
  54
  55     rv = CryptAcquireContext(&cryptprovider, NULL,
  56                               MS_ENHANCED_PROV, PROV_RSA_FULL,
  57                               CRYPT_VERIFYCONTEXT);
  58
  59     if (GetLastError() == NTE_BAD_KEYSET) {
  60         rv = CryptAcquireContext(&cryptprovider, NULL,
  61                                  MS_ENHANCED_PROV, PROV_RSA_FULL,
  62                                  CRYPT_NEWKEYSET);
  63     }
  64
  65     if (rv) {
  66         /* try the default provider */
  67         rv = CryptAcquireContext(&cryptprovider, NULL, 0, PROV_RSA_FULL,
  68                                  CRYPT_VERIFYCONTEXT);
  69
  70         if (GetLastError() == NTE_BAD_KEYSET) {
  71             rv = CryptAcquireContext(&cryptprovider, NULL,
  72                                      MS_ENHANCED_PROV, PROV_RSA_FULL,
  73                                      CRYPT_NEWKEYSET);
  74         }
  75     }
  76
  77     if (rv) {
  78         /* try just a default random number generator */
  79         rv = CryptAcquireContext(&cryptprovider, NULL, 0, PROV_RNG,
  80                                  CRYPT_VERIFYCONTEXT);
  81     }
  82
  83     if (rv == 0 &&
  84         InterlockedCompareExchangePointer((PVOID *) &g_cryptprovider,
  85                                           (PVOID) cryptprovider, NULL) != 0) {
  86
  87         CryptReleaseContext(cryptprovider, 0);
  88     }
  89
  90 out:
  91     return g_cryptprovider;
  92 }
  93
  94 /*
  95  *
  96  */
  97
  98
  99 static void
 100 w32crypto_seed(const void *indata, int size)
 101 {
 102 }
 103
 104
 105 static int
 106 w32crypto_bytes(unsigned char *outdata, int size)
 107 {
 108     if (CryptGenRandom(_hc_CryptProvider(), size, outdata))
 109         return 1;
 110     return 0;
 111 }
 112
 113 static void
 114 w32crypto_cleanup(void)
 115 {
 116     HCRYPTPROV cryptprovider;
 117
 118     if (InterlockedCompareExchangePointer((PVOID *) &cryptprovider,
 119                                           0, (PVOID) g_cryptprovider) == 0) {
 120         CryptReleaseContext(cryptprovider, 0);
 121     }
 122 }
 123
 124 static void
 125 w32crypto_add(const void *indata, int size, double entropi)
 126 {
 127 }
 128
 129 static int
 130 w32crypto_status(void)
 131 {
 132     if (_hc_CryptProvider() == 0)
 133         return 0;
 134     return 1;
 135 }
 136
 137 const RAND_METHOD hc_rand_w32crypto_method = {
 138     w32crypto_seed,
 139     w32crypto_bytes,
 140     w32crypto_cleanup,
 141     w32crypto_add,
 142     w32crypto_bytes,
 143     w32crypto_status
 144 };
 145
 146 const RAND_METHOD *
 147 RAND_w32crypto_method(void)
 148 {
 149     return &hc_rand_w32crypto_method;
 150 }