lib/hcrypto/rand-egd.c

   1 /*
   2  * Copyright (c) 2007 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 <sys/types.h>
  41 #ifdef HAVE_SYS_UN_H
  42 #include <sys/un.h>
  43 #endif
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #ifdef HAVE_UNISTD_H
  48 #include <unistd.h>
  49 #endif
  50 #include <assert.h>
  51
  52 #include <rand.h>
  53 #include <randi.h>
  54
  55 #include <roken.h>
  56
  57 static const char *egd_path = "/var/run/egd-pool";
  58
  59 #define MAX_EGD_DATA 255
  60
  61 static int
  62 connect_egd(const char *path)
  63 {
  64     struct sockaddr_un addr;
  65     int fd;
  66
  67     memset(&addr, 0, sizeof(addr));
  68
  69     if (strlen(path) > sizeof(addr.sun_path))
  70         return -1;
  71
  72     addr.sun_family = AF_UNIX;
  73     strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
  74
  75     fd = socket(AF_UNIX, SOCK_STREAM, 0);
  76     if (fd < 0)
  77         return -1;
  78
  79     if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) != 0) {
  80         close(fd);
  81         return -1;
  82     }
  83
  84     return fd;
  85 }
  86
  87 static int
  88 get_entropy(int fd, void *data, size_t len)
  89 {
  90     unsigned char msg[2];
  91
  92     assert(len <= MAX_EGD_DATA);
  93
  94     msg[0] = 0x02; /* read blocking data */
  95     msg[1] = len; /* wanted length */
  96
  97     if (net_write(fd, msg, sizeof(msg)) != sizeof(msg))
  98         return 0;
  99
 100     if (net_read(fd, data, len) != len)
 101         return 0;
 102
 103     return 1;
 104 }
 105
 106 static int
 107 put_entropy(int fd, const void *data, size_t len)
 108 {
 109     unsigned char msg[4];
 110
 111     assert (len <= MAX_EGD_DATA);
 112
 113     msg[0] = 0x03; /* write data */
 114     msg[1] = 0; /* dummy */
 115     msg[2] = 0; /* entropy */
 116     msg[3] = len; /* length */
 117
 118     if (net_write(fd, msg, sizeof(msg)) != sizeof(msg))
 119         return 0;
 120     if (net_write(fd, data, len) != len)
 121         return 0;
 122
 123     return 1;
 124 }
 125
 126 /*
 127  *
 128  */
 129
 130 static void
 131 egd_seed(const void *indata, int size)
 132 {
 133     size_t len;
 134     int fd, ret = 1;
 135
 136     fd = connect_egd(egd_path);
 137     if (fd < 0)
 138         return;
 139
 140     while(size) {
 141         len = size;
 142         if (len > MAX_EGD_DATA)
 143             len = MAX_EGD_DATA;
 144         ret = put_entropy(fd, indata, len);
 145         if (ret != 1)
 146             break;
 147         indata = ((unsigned char *)indata) + len;
 148         size -= len;
 149     }
 150     close(fd);
 151 }
 152
 153 static int
 154 get_bytes(const char *path, unsigned char *outdata, int size)
 155 {
 156     size_t len;
 157     int fd, ret = 1;
 158
 159     if (path == NULL)
 160         path = egd_path;
 161
 162     fd = connect_egd(path);
 163     if (fd < 0)
 164         return 0;
 165
 166     while(size) {
 167         len = size;
 168         if (len > MAX_EGD_DATA)
 169             len = MAX_EGD_DATA;
 170         ret = get_entropy(fd, outdata, len);
 171         if (ret != 1)
 172             break;
 173         outdata += len;
 174         size -= len;
 175     }
 176     close(fd);
 177
 178     return ret;
 179 }
 180
 181 static int
 182 egd_bytes(unsigned char *outdata, int size)
 183 {
 184     return get_bytes(NULL, outdata, size);
 185 }
 186
 187 static void
 188 egd_cleanup(void)
 189 {
 190 }
 191
 192 static void
 193 egd_add(const void *indata, int size, double entropi)
 194 {
 195     egd_seed(indata, size);
 196 }
 197
 198 static int
 199 egd_pseudorand(unsigned char *outdata, int size)
 200 {
 201     return get_bytes(NULL, outdata, size);
 202 }
 203
 204 static int
 205 egd_status(void)
 206 {
 207     int fd;
 208     fd = connect_egd(egd_path);
 209     if (fd < 0)
 210         return 0;
 211     close(fd);
 212     return 1;
 213 }
 214
 215 const RAND_METHOD hc_rand_egd_method = {
 216     egd_seed,
 217     egd_bytes,
 218     egd_cleanup,
 219     egd_add,
 220     egd_pseudorand,
 221     egd_status
 222 };
 223
 224 const RAND_METHOD *
 225 RAND_egd_method(void)
 226 {
 227     return &hc_rand_egd_method;
 228 }
 229
 230
 231 int
 232 RAND_egd(const char *filename)
 233 {
 234     return RAND_egd_bytes(filename, 128);
 235 }
 236
 237 int
 238 RAND_egd_bytes(const char *filename, int size)
 239 {
 240     void *data;
 241     int ret;
 242
 243     if (size <= 0)
 244         return 0;
 245
 246     data = malloc(size);
 247     if (data == NULL)
 248         return 0;
 249
 250     ret = get_bytes(filename, data, size);
 251     if (ret != 1) {
 252         free(data);
 253         return ret;
 254     }
 255
 256     RAND_seed(data, size);
 257
 258     memset(data, 0, size);
 259     free(data);
 260
 261     return 1;
 262 }