1 kumpf 1.2 /*
  2           //%2006////////////////////////////////////////////////////////////////////////
  3           //
  4           // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
  5           // Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
  6           // Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
  7           // IBM Corp.; EMC Corporation, The Open Group.
  8           // Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
  9           // IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
 10           // Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
 11           // EMC Corporation; VERITAS Software Corporation; The Open Group.
 12           // Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
 13           // EMC Corporation; Symantec Corporation; The Open Group.
 14           //
 15           // Permission is hereby granted, free of charge, to any person obtaining a copy
 16           // of this software and associated documentation files (the "Software"), to
 17           // deal in the Software without restriction, including without limitation the
 18           // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 19           // sell copies of the Software, and to permit persons to whom the Software is
 20           // furnished to do so, subject to the following conditions:
 21           // 
 22 kumpf 1.2 // THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
 23           // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
 24           // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 25           // LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 26           // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 27           // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 28           // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 29           // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 30           //
 31           //%/////////////////////////////////////////////////////////////////////////////
 32           */
 33           
 34           #include "Random.h"
 35           #include <stdlib.h>
 36           #include <sys/types.h>
 37           #include <sys/stat.h>
 38           #include <sys/time.h>
 39           #include <fcntl.h>
 40           #include <unistd.h>
 41           #include <errno.h>
 42           
 43 kumpf 1.2 /*
 44           **==============================================================================
 45           **
 46           ** FillRandomBytes1()
 47           **
 48           **     Fills *data* with *size* random bytes using the high-quality random
 49           **     number generator device (/dev/urandom).
 50           **
 51           **==============================================================================
 52           */
 53           
 54           static int _fillRandomBytes1(unsigned char* data, size_t size)
 55           {
 56               size_t numErrors = 0;
 57               const size_t MAX_ERRORS_TOLERATED = 20;
 58           
 59               int fd = open("/dev/urandom", O_RDONLY | O_NONBLOCK);
 60           
 61               if (fd < 0)
 62                   return -1;
 63           
 64 kumpf 1.2     while (size)
 65               {
 66                   ssize_t n = read(fd, data, size);
 67           
 68                   if (n < 1)
 69                   {
 70                       if (++numErrors == MAX_ERRORS_TOLERATED)
 71                           break;
 72           
 73                       if (errno == EAGAIN)
 74                           continue;
 75           
 76                       break;
 77                   }
 78           
 79                   size -= n;
 80                   data += n;
 81               }
 82           
 83               close(fd);
 84               return size == 0 ? 0 : -1;
 85 kumpf 1.2 }
 86           
 87           /*
 88           **==============================================================================
 89           **
 90           ** FillRandomBytes2()
 91           **
 92           **     Fills *data* with *size* random bytes using the standard rand() function.
 93           **     Note: this function uses srand(), which is generally not considered
 94           **     "random" enough for security purposes but it is only used if
 95           **     FillRandomBytes1() fails.
 96           **
 97           **==============================================================================
 98           */
 99           
100           static void _fillRandomBytes2(unsigned char* data, size_t size)
101           {
102               struct timeval tv;
103           
104               /* Seed the random number generator. */
105           
106 kumpf 1.2     gettimeofday(&tv, 0);
107           
108               /* Flawfinder: ignore */
109               srand(tv.tv_usec);
110           
111               /* Fill data with random bytes. */
112           
113               while (size--)
114                   *data++ = rand();
115           }
116           
117           /*
118           **==============================================================================
119           **
120           ** FillRandomBytes()
121           **
122           **==============================================================================
123           */
124           
125           void FillRandomBytes(unsigned char* data, size_t size)
126           {
127 kumpf 1.2     if (_fillRandomBytes1(data, size) != 0)
128                   _fillRandomBytes2(data, size);
129           }
130           
131           /*
132           **==============================================================================
133           **
134           ** RandBytesToHexASCII()
135           **
136           **     Converts the bytes given by *data* to a hexidecimal sequence of ASCII
137           **     characters. The *ascii* parameter must be twice size plus one (for the
138           **     null terminator).
139           **
140           **==============================================================================
141           */
142           
143           void RandBytesToHexASCII(
144               const unsigned char* data,
145               size_t size,
146               char* ascii)
147           {
148 kumpf 1.2     static char _hexDigits[] =
149               {
150                   '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
151               };
152               size_t i;
153               size_t j = 0;
154           
155               for (i = 0; i < size; i++)
156               {
157                   unsigned char hi = data[i] >> 4;
158                   unsigned char lo = 0x0F & data[i];
159                   ascii[j++] = _hexDigits[hi];
160                   ascii[j++] = _hexDigits[lo];
161               }
162           
163               ascii[j] = '\0';
164           }