1/* 2 * Copyright (c) 2006 Kungliga Tekniska H��gskolan 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#include <config.h> 35 36#include <stdio.h> 37#include <stdlib.h> 38#include <rand.h> 39#include <heim_threads.h> 40 41#include <roken.h> 42 43#include "randi.h" 44 45static int random_fd = -1; 46static HEIMDAL_MUTEX random_mutex = HEIMDAL_MUTEX_INITIALIZER; 47 48/* 49 * Unix /dev/random 50 */ 51 52static int 53get_device_fd(int flags) 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 74static void 75unix_seed(const void *indata, int size) 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 92static int 93unix_bytes(unsigned char *outdata, int size) 94{ 95 ssize_t count; 96 int once = 0; 97 98 if (size <= 0) 99 return 0; 100 101 HEIMDAL_MUTEX_lock(&random_mutex); 102 if (random_fd == -1) { 103 retry: 104 random_fd = get_device_fd(O_RDONLY); 105 if (random_fd < 0) { 106 HEIMDAL_MUTEX_unlock(&random_mutex); 107 return 0; 108 } 109 } 110 111 while (size > 0) { 112 HEIMDAL_MUTEX_unlock(&random_mutex); 113 count = read (random_fd, outdata, size); 114 HEIMDAL_MUTEX_lock(&random_mutex); 115 if (random_fd < 0) { 116 if (errno == EINTR) 117 continue; 118 else if (errno == EBADF && once++ == 0) { 119 close(random_fd); 120 random_fd = -1; 121 goto retry; 122 } 123 return 0; 124 } else if (count <= 0) { 125 HEIMDAL_MUTEX_unlock(&random_mutex); 126 return 0; 127 } 128 outdata += count; 129 size -= count; 130 } 131 HEIMDAL_MUTEX_unlock(&random_mutex); 132 133 return 1; 134} 135 136static void 137unix_cleanup(void) 138{ 139} 140 141static void 142unix_add(const void *indata, int size, double entropi) 143{ 144 unix_seed(indata, size); 145} 146 147static int 148unix_pseudorand(unsigned char *outdata, int size) 149{ 150 return unix_bytes(outdata, size); 151} 152 153static int 154unix_status(void) 155{ 156 int fd; 157 158 fd = get_device_fd(O_RDONLY); 159 if (fd < 0) 160 return 0; 161 close(fd); 162 163 return 1; 164} 165 166const RAND_METHOD hc_rand_unix_method = { 167 unix_seed, 168 unix_bytes, 169 unix_cleanup, 170 unix_add, 171 unix_pseudorand, 172 unix_status 173}; 174 175const RAND_METHOD * 176RAND_unix_method(void) 177{ 178 return &hc_rand_unix_method; 179} 180