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      1 /*	$NetBSD: rand-w32.c,v 1.2 2017/01/28 21:31:47 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2006 Kungliga Tekniska Hgskolan
      5  * (Royal Institute of Technology, Stockholm, Sweden).
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  *
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * 3. Neither the name of the Institute nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <config.h>
     37 #include <krb5/roken.h>
     38 
     39 #include <wincrypt.h>
     40 
     41 #include <rand.h>
     42 #include <heim_threads.h>
     43 
     44 #include "randi.h"
     45 
     46 volatile static HCRYPTPROV g_cryptprovider = NULL;
     47 
     48 static HCRYPTPROV
     49 _hc_CryptProvider(void)
     50 {
     51     BOOL rv;
     52     HCRYPTPROV cryptprovider = NULL;
     53 
     54     if (g_cryptprovider != NULL)
     55 	goto out;
     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 == 0 &&
     86         InterlockedCompareExchangePointer((PVOID *) &g_cryptprovider,
     87 					  (PVOID) cryptprovider, NULL) != 0) {
     88 
     89         CryptReleaseContext(cryptprovider, 0);
     90     }
     91 
     92 out:
     93     return g_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 }
    153