1 /*- 2 * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com> 3 * Copyright (c) 2000-2004 Mark R V Murray 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/selinfo.h> 48 #include <sys/uio.h> 49 #include <sys/unistd.h> 50 51 #include <machine/bus.h> 52 #include <machine/cpu.h> 53 54 #include <dev/random/random_adaptors.h> 55 #include <dev/random/randomdev.h> 56 57 #define RANDOM_MINOR 0 58 59 static d_close_t random_close; 60 static d_read_t random_read; 61 static d_write_t random_write; 62 static d_ioctl_t random_ioctl; 63 static d_poll_t random_poll; 64 65 static struct cdevsw random_cdevsw = { 66 .d_version = D_VERSION, 67 .d_close = random_close, 68 .d_read = random_read, 69 .d_write = random_write, 70 .d_ioctl = random_ioctl, 71 .d_poll = random_poll, 72 .d_name = "random", 73 }; 74 75 static eventhandler_tag attach_tag; 76 static int random_inited; 77 78 /* For use with make_dev(9)/destroy_dev(9). */ 79 static struct cdev *random_dev; 80 81 /* ARGSUSED */ 82 static int 83 random_close(struct cdev *dev __unused, int flags, int fmt __unused, 84 struct thread *td) 85 { 86 if ((flags & FWRITE) && (priv_check(td, PRIV_RANDOM_RESEED) == 0) 87 && (securelevel_gt(td->td_ucred, 0) == 0)) { 88 (*random_adaptor->reseed)(); 89 random_adaptor->seeded = 1; 90 arc4rand(NULL, 0, 1); /* Reseed arc4random as well. */ 91 } 92 93 return (0); 94 } 95 96 /* ARGSUSED */ 97 static int 98 random_read(struct cdev *dev __unused, struct uio *uio, int flag) 99 { 100 int c, error = 0; 101 void *random_buf; 102 103 /* Blocking logic */ 104 if (!random_adaptor->seeded) 105 error = (*random_adaptor->block)(flag); 106 107 /* The actual read */ 108 if (!error) { 109 110 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 111 112 while (uio->uio_resid > 0 && !error) { 113 c = MIN(uio->uio_resid, PAGE_SIZE); 114 c = (*random_adaptor->read)(random_buf, c); 115 error = uiomove(random_buf, c, uio); 116 } 117 118 free(random_buf, M_TEMP); 119 120 } 121 122 return (error); 123 } 124 125 /* ARGSUSED */ 126 static int 127 random_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 128 { 129 int c, error = 0; 130 void *random_buf; 131 132 random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 133 134 while (uio->uio_resid > 0) { 135 c = MIN((int)uio->uio_resid, PAGE_SIZE); 136 error = uiomove(random_buf, c, uio); 137 if (error) 138 break; 139 (*random_adaptor->write)(random_buf, c); 140 } 141 142 free(random_buf, M_TEMP); 143 144 return (error); 145 } 146 147 /* ARGSUSED */ 148 static int 149 random_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 150 int flags __unused, struct thread *td __unused) 151 { 152 int error = 0; 153 154 switch (cmd) { 155 /* Really handled in upper layer */ 156 case FIOASYNC: 157 case FIONBIO: 158 break; 159 default: 160 error = ENOTTY; 161 } 162 return (error); 163 } 164 165 /* ARGSUSED */ 166 static int 167 random_poll(struct cdev *dev __unused, int events, struct thread *td) 168 { 169 int revents = 0; 170 171 if (events & (POLLIN | POLLRDNORM)) { 172 if (random_adaptor->seeded) 173 revents = events & (POLLIN | POLLRDNORM); 174 else 175 revents = (*random_adaptor->poll) (events,td); 176 } 177 return (revents); 178 } 179 180 static void 181 random_initialize(void *p, struct random_adaptor *s) 182 { 183 if (random_inited) { 184 printf("random: <%s> already initialized\n", 185 random_adaptor->ident); 186 return; 187 } 188 189 random_adaptor = s; 190 191 (s->init)(); 192 193 printf("random: <%s> initialized\n", s->ident); 194 195 random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw, 196 RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random"); 197 make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 198 199 /* mark random(4) as initialized, to avoid being called again */ 200 random_inited = 1; 201 } 202 203 /* ARGSUSED */ 204 static int 205 random_modevent(module_t mod __unused, int type, void *data __unused) 206 { 207 int error = 0; 208 209 switch (type) { 210 case MOD_LOAD: 211 random_adaptor_choose(&random_adaptor); 212 213 if (random_adaptor == NULL) { 214 printf( 215 "random: No random adaptor attached, postponing initialization\n"); 216 attach_tag = EVENTHANDLER_REGISTER(random_adaptor_attach, 217 random_initialize, NULL, EVENTHANDLER_PRI_ANY); 218 } else { 219 random_initialize(NULL, random_adaptor); 220 } 221 222 break; 223 224 case MOD_UNLOAD: 225 if (random_adaptor != NULL) { 226 (*random_adaptor->deinit)(); 227 destroy_dev(random_dev); 228 } 229 /* Unregister the event handler */ 230 if (attach_tag != NULL) { 231 EVENTHANDLER_DEREGISTER(random_adaptor_attach, 232 attach_tag); 233 } 234 235 break; 236 237 case MOD_SHUTDOWN: 238 break; 239 240 default: 241 error = EOPNOTSUPP; 242 break; 243 244 } 245 return (error); 246 } 247 248 DEV_MODULE(random, random_modevent, NULL); 249 MODULE_VERSION(random, 1); 250