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      1 /*
      2  * Copyright (C) 2011 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY GOOGLE, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "OSRandomSource.h"
     28 
     29 #include <stdint.h>
     30 #include <stdlib.h>
     31 
     32 #if OS(SYMBIAN)
     33 #include <e32math.h>
     34 #endif
     35 
     36 #if OS(UNIX)
     37 #include <fcntl.h>
     38 #include <unistd.h>
     39 #endif
     40 
     41 #if OS(WINDOWS)
     42 #include <windows.h>
     43 #include <wincrypt.h> // windows.h must be included before wincrypt.h.
     44 #endif
     45 
     46 namespace WTF {
     47 
     48 #if USE(OS_RANDOMNESS)
     49 void cryptographicallyRandomValuesFromOS(unsigned char* buffer, size_t length)
     50 {
     51 #if OS(SYMBIAN)
     52     TInt random;
     53     while (length > sizeof(random)) {
     54         random = Math::Random();
     55         memcpy(buffer, &random, sizeof(random));
     56         length -= sizeof(random);
     57         buffer += sizeof(random);
     58     }
     59     if (length > 0) {
     60         random = Math::Random();
     61         memcpy(buffer, &random, length);
     62     }
     63 #elif OS(UNIX)
     64     int fd = open("/dev/urandom", O_RDONLY, 0);
     65     if (fd < 0)
     66         CRASH(); // We need /dev/urandom for this API to work...
     67 
     68     if (read(fd, buffer, length) != static_cast<ssize_t>(length))
     69         CRASH();
     70 
     71     close(fd);
     72 #elif OS(WINDOWS)
     73     HCRYPTPROV hCryptProv = 0;
     74     if (!CryptAcquireContext(&hCryptProv, 0, MS_DEF_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
     75         CRASH();
     76     if (!CryptGenRandom(hCryptProv, length, buffer))
     77         CRASH();
     78     CryptReleaseContext(hCryptProv, 0);
     79 #else
     80     #error "This configuration doesn't have a strong source of randomness."
     81     // WARNING: When adding new sources of OS randomness, the randomness must
     82     //          be of cryptographic quality!
     83 #endif
     84 }
     85 #endif
     86 
     87 }
     88