root/source4/heimdal/lib/hcrypto/rand-unix.c

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DEFINITIONS

This source file includes following definitions.
  1. get_device_fd
  2. unix_seed
  3. unix_bytes
  4. unix_cleanup
  5. unix_add
  6. unix_pseudorand
  7. unix_status
  8. RAND_unix_method

   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("$Id$");
  39 
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <rand.h>
  43 
  44 #include <roken.h>
  45 
  46 #include "randi.h"
  47 
  48 /*
  49  * Unix /dev/random
  50  */
  51 
  52 static int
  53 get_device_fd(int flags)
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  54 {
  55     static const char *rnd_devices[] = {
  56         "/dev/urandom",
  57         "/dev/random",
  58         "/dev/srandom",
  59         "/dev/arandom",
  60         NULL
  61     };
  62     const char **p;
  63 
  64     for(p = rnd_devices; *p; p++) {
  65         int fd = open(*p, flags | O_NDELAY);
  66         if(fd >= 0) {
  67             rk_cloexec(fd);
  68             return fd;
  69         }
  70     }
  71     return -1;
  72 }
  73 
  74 static void
  75 unix_seed(const void *indata, int size)
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  76 {
  77     int fd;
  78 
  79     if (size <= 0)
  80         return;
  81 
  82     fd = get_device_fd(O_WRONLY);
  83     if (fd < 0)
  84         return;
  85 
  86     write(fd, indata, size);
  87     close(fd);
  88 
  89 }
  90 
  91 static int
  92 unix_bytes(unsigned char *outdata, int size)
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  93 {
  94     ssize_t count;
  95     int fd;
  96 
  97     if (size <= 0)
  98         return 0;
  99 
 100     fd = get_device_fd(O_RDONLY);
 101     if (fd < 0)
 102         return 0;
 103 
 104     while (size > 0) {
 105         count = read (fd, outdata, size);
 106         if (count < 0 && errno == EINTR)
 107             continue;
 108         else if (count <= 0) {
 109             close(fd);
 110             return 0;
 111         }
 112         outdata += count;
 113         size -= count;
 114     }
 115     close(fd);
 116 
 117     return 1;
 118 }
 119 
 120 static void
 121 unix_cleanup(void)
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 122 {
 123 }
 124 
 125 static void
 126 unix_add(const void *indata, int size, double entropi)
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 127 {
 128     unix_seed(indata, size);
 129 }
 130 
 131 static int
 132 unix_pseudorand(unsigned char *outdata, int size)
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 133 {
 134     return unix_bytes(outdata, size);
 135 }
 136 
 137 static int
 138 unix_status(void)
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 139 {
 140     int fd;
 141 
 142     fd = get_device_fd(O_RDONLY);
 143     if (fd < 0)
 144         return 0;
 145     close(fd);
 146 
 147     return 1;
 148 }
 149 
 150 const RAND_METHOD hc_rand_unix_method = {
 151     unix_seed,
 152     unix_bytes,
 153     unix_cleanup,
 154     unix_add,
 155     unix_pseudorand,
 156     unix_status
 157 };
 158 
 159 const RAND_METHOD *
 160 RAND_unix_method(void)
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 161 {
 162     return &hc_rand_unix_method;
 163 }

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