rngd_linux.c

   1 /*
   2  * rngd_linux.c -- Entropy sink for the Linux Kernel (/dev/random)
   3  *
   4  * Copyright (C) 2001 Philipp Rumpf
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #define _GNU_SOURCE
  22
  23 #ifndef HAVE_CONFIG_H
  24 #error Invalid or missing autoconf build environment
  25 #endif
  26
  27 #include "rng-tools-config.h"
  28
  29 #include <unistd.h>
  30 #include <stdint.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <errno.h>
  34 #include <syslog.h>
  35 #include <sys/ioctl.h>
  36 #include <sys/poll.h>
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39 #include <fcntl.h>
  40 #include <sys/time.h>
  41 #include <time.h>
  42 #include <linux/types.h>
  43 #include <linux/random.h>
  44 #include <string.h>
  45
  46 #include "rngd.h"
  47 #include "fips.h"
  48 #include "exits.h"
  49 #include "rngd_linux.h"
  50
  51 extern struct rng *rng_list;
  52
  53 /* Kernel output device */
  54 static int random_fd;
  55
  56
  57 /*
  58  * Initialize the interface to the Linux Kernel
  59  * entropy pool (through /dev/random)
  60  *
  61  * randomdev is the path to the random device
  62  */
  63 void init_kernel_rng(const char* randomdev)
  64 {
  65         random_fd = open(randomdev, O_RDWR);
  66         if (random_fd == -1) {
  67                 message(LOG_DAEMON|LOG_ERR, "can't open %s: %s",
  68                         randomdev, strerror(errno));
  69                 exit(EXIT_USAGE);
  70         }
  71 }
  72
  73 void random_add_entropy(void *buf, size_t size)
  74 {
  75         struct {
  76                 int ent_count;
  77                 int size;
  78                 unsigned char data[size];
  79         } entropy;
  80
  81         entropy.ent_count = size * 8;
  82         entropy.size = size;
  83         memcpy(entropy.data, buf, size);
  84
  85         if (ioctl(random_fd, RNDADDENTROPY, &entropy) != 0) {
  86                 message(LOG_DAEMON|LOG_ERR, "RNDADDENTROPY failed: %s\n",
  87                         strerror(errno));
  88                 exit(1);
  89         }
  90 }
  91
  92 void random_sleep(double poll_timeout)
  93 {
  94         int ent_count;
  95         struct pollfd pfd = {
  96                 fd:     random_fd,
  97                 events: POLLOUT,
  98         };
  99
 100         if (ioctl(random_fd, RNDGETENTCNT, &ent_count) == 0 &&
 101             ent_count < arguments->fill_watermark)
 102                 return;
 103
 104         poll(&pfd, 1, 1000.0 * poll_timeout);
 105 }
 106
 107 void src_list_add(struct rng *ent_src)
 108 {
 109         if (rng_list) {
 110                 struct rng *iter;
 111
 112                 iter = rng_list;
 113                 while (iter->next) {
 114                         iter = iter->next;
 115                 }
 116                 iter->next = ent_src;
 117         } else {
 118                 rng_list = ent_src;
 119         }
 120 }