source/heimdal/lib/des/rand-unix.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 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 RCSID("$Id: rand-unix.c,v 1.2 2006/10/21 21:09:14 lha Exp $");
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <rand.h>
  43
  44 #include <roken.h>
  45
  46 /*
  47  * Unix /dev/random
  48  */
  49
  50 static int
  51 get_device_fd(int flags)
  52 {
  53     static const char *rnd_devices[] = {
  54         "/dev/urandom",
  55         "/dev/random",
  56         "/dev/srandom",
  57         "/dev/arandom",
  58         NULL
  59     };
  60     const char **p;
  61
  62     for(p = rnd_devices; *p; p++) {
  63         int fd = open(*p, flags | O_NDELAY);
  64         if(fd >= 0)
  65             return fd;
  66     }
  67     return -1;
  68 }
  69
  70 static void
  71 unix_seed(const void *indata, int size)
  72 {
  73     int fd;
  74
  75     if (size <= 0)
  76         return;
  77
  78     fd = get_device_fd(O_WRONLY);
  79     if (fd < 0)
  80         return;
  81
  82     write(fd, indata, size);
  83     close(fd);
  84
  85 }
  86
  87 static int
  88 unix_bytes(unsigned char *outdata, int size)
  89 {
  90     ssize_t count;
  91     int fd;
  92
  93     if (size <= 0)
  94         return 0;
  95
  96     fd = get_device_fd(O_RDONLY);
  97     if (fd < 0)
  98         return 0;
  99
 100     while (size > 0) {
 101         count = read (fd, outdata, size);
 102         if (count < 0 && errno == EINTR)
 103             continue;
 104         else if (count <= 0) {
 105             close(fd);
 106             return 0;
 107         }
 108         outdata += count;
 109         size -= count;
 110     }
 111     close(fd);
 112
 113     return 1;
 114 }
 115
 116 static void
 117 unix_cleanup(void)
 118 {
 119 }
 120
 121 static void
 122 unix_add(const void *indata, int size, double entropi)
 123 {
 124     unix_seed(indata, size);
 125 }
 126
 127 static int
 128 unix_pseudorand(unsigned char *outdata, int size)
 129 {
 130     return unix_bytes(outdata, size);
 131 }
 132
 133 static int
 134 unix_status(void)
 135 {
 136     int fd;
 137
 138     fd = get_device_fd(O_RDONLY);
 139     if (fd < 0)
 140         return 0;
 141     close(fd);
 142
 143     return 1;
 144 }
 145
 146 const RAND_METHOD hc_rand_unix_method = {
 147     unix_seed,
 148     unix_bytes,
 149     unix_cleanup,
 150     unix_add,
 151     unix_pseudorand,
 152     unix_status
 153 };