1 /*- 2 * Copyright (c) 2000-2013 Mark R V Murray 3 * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com> 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 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer 11 * in this position and unchanged. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/bus.h> 35 #include <sys/conf.h> 36 #include <sys/fcntl.h> 37 #include <sys/filio.h> 38 #include <sys/kernel.h> 39 #include <sys/kthread.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/module.h> 43 #include <sys/mutex.h> 44 #include <sys/poll.h> 45 #include <sys/priv.h> 46 #include <sys/proc.h> 47 #include <sys/random.h> 48 #include <sys/selinfo.h> 49 #include <sys/uio.h> 50 #include <sys/unistd.h> 51 52 #include <machine/bus.h> 53 #include <machine/cpu.h> 54 55 #include <dev/random/randomdev.h> 56 #include <dev/random/randomdev_soft.h> 57 #include <dev/random/random_adaptors.h> 58 #include <dev/random/random_harvestq.h> 59 #include <dev/random/live_entropy_sources.h> 60 61 #define RANDOM_MINOR 0 62 63 static d_read_t random_read; 64 static d_write_t random_write; 65 static d_ioctl_t random_ioctl; 66 static d_poll_t random_poll; 67 68 static struct cdevsw random_cdevsw = { 69 .d_version = D_VERSION, 70 .d_read = random_read, 71 .d_write = random_write, 72 .d_ioctl = random_ioctl, 73 .d_poll = random_poll, 74 .d_name = "random", 75 }; 76 77 /* For use with make_dev(9)/destroy_dev(9). */ 78 static struct cdev *random_dev; 79 80 /* ARGSUSED */ 81 static int 82 random_read(struct cdev *dev __unused, struct uio *uio, int flag) 83 { 84 int c, error = 0; 85 void *random_buf; 86 87 /* Blocking logic */ 88 if (!random_adaptor->seeded) 89 error = (*random_adaptor->block)(flag); 90 91 /* The actual read */ 92 if (!error) { 93 94 random_buf = (void *)malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK); 95 96 while (uio->uio_resid > 0 && !error) { 97 c = MIN(uio->uio_resid, PAGE_SIZE); 98 c = (*random_adaptor->read)(random_buf, c); 99 error = uiomove(random_buf, c, uio); 100 } 101 /* Finished reading; let the source know so it can do some 102 * optional housekeeping */ 103 (*random_adaptor->read)(NULL, 0); 104 105 free(random_buf, M_ENTROPY); 106 107 } 108 109 return (error); 110 } 111 112 /* ARGSUSED */ 113 static int 114 random_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 115 { 116 117 /* We used to allow this to insert userland entropy. 118 * We don't any more because (1) this so-called entropy 119 * is usually lousy and (b) its vaguely possible to 120 * mess with entropy harvesting by overdoing a write. 121 * Now we just ignore input like /dev/null does. 122 */ 123 uio->uio_resid = 0; 124 125 return (0); 126 } 127 128 /* ARGSUSED */ 129 static int 130 random_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 131 int flags __unused, struct thread *td __unused) 132 { 133 int error = 0; 134 135 switch (cmd) { 136 /* Really handled in upper layer */ 137 case FIOASYNC: 138 case FIONBIO: 139 break; 140 default: 141 error = ENOTTY; 142 } 143 return (error); 144 } 145 146 /* ARGSUSED */ 147 static int 148 random_poll(struct cdev *dev __unused, int events, struct thread *td) 149 { 150 int revents = 0; 151 152 if (events & (POLLIN | POLLRDNORM)) { 153 if (random_adaptor->seeded) 154 revents = events & (POLLIN | POLLRDNORM); 155 else 156 revents = (*random_adaptor->poll)(events, td); 157 } 158 return (revents); 159 } 160 161 static void 162 random_initialize(void *p, struct random_adaptor *s) 163 { 164 static int random_inited = 0; 165 166 if (random_inited) { 167 printf("random: <%s> already initialized\n", 168 random_adaptor->ident); 169 return; 170 } 171 172 random_adaptor = s; 173 174 (s->init)(); 175 176 printf("random: <%s> initialized\n", s->ident); 177 178 /* Use an appropriately evil mode for those who are concerned 179 * with daemons */ 180 random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw, 181 RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random"); 182 make_dev_alias(random_dev, "urandom"); /* compatibility */ 183 184 /* mark random(4) as initialized, to avoid being called again */ 185 random_inited = 1; 186 } 187 188 /* ARGSUSED */ 189 static int 190 random_modevent(module_t mod __unused, int type, void *data __unused) 191 { 192 static eventhandler_tag attach_tag = NULL; 193 int error = 0; 194 195 switch (type) { 196 case MOD_LOAD: 197 random_adaptor_choose(&random_adaptor); 198 199 if (random_adaptor == NULL) { 200 printf("random: No random adaptor attached, " 201 "postponing initialization\n"); 202 attach_tag = EVENTHANDLER_REGISTER(random_adaptor_attach, 203 random_initialize, NULL, EVENTHANDLER_PRI_ANY); 204 } else 205 random_initialize(NULL, random_adaptor); 206 207 break; 208 209 case MOD_UNLOAD: 210 if (random_adaptor != NULL) { 211 (*random_adaptor->deinit)(); 212 destroy_dev(random_dev); 213 } 214 /* Unregister the event handler */ 215 if (attach_tag != NULL) 216 EVENTHANDLER_DEREGISTER(random_adaptor_attach, 217 attach_tag); 218 219 break; 220 221 case MOD_SHUTDOWN: 222 break; 223 224 default: 225 error = EOPNOTSUPP; 226 break; 227 228 } 229 return (error); 230 } 231 232 DEV_MODULE(random, random_modevent, NULL); 233 MODULE_VERSION(random, 1); 234