randomdev.c revision 216952
125428Speter/*- 250477Speter * Copyright (c) 2000-2004 Mark R V Murray 325428Speter * All rights reserved. 4139823Simp * 525428Speter * Redistribution and use in source and binary forms, with or without 625428Speter * modification, are permitted provided that the following conditions 725428Speter * are met: 825428Speter * 1. Redistributions of source code must retain the above copyright 925428Speter * notice, this list of conditions and the following disclaimer 1025428Speter * in this position and unchanged. 1125428Speter * 2. Redistributions in binary form must reproduce the above copyright 1225428Speter * notice, this list of conditions and the following disclaimer in the 1325428Speter * documentation and/or other materials provided with the distribution. 1425428Speter * 1525428Speter * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1625428Speter * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1725428Speter * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1825428Speter * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1925428Speter * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2025428Speter * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2125428Speter * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2225428Speter * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2325428Speter * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2425428Speter * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2525428Speter * 2625428Speter */ 2725428Speter 2825428Speter#include <sys/cdefs.h> 2925428Speter__FBSDID("$FreeBSD: head/sys/dev/random/randomdev.c 216952 2011-01-04 10:59:38Z kib $"); 3025428Speter 3125428Speter#include <sys/param.h> 3225428Speter#include <sys/systm.h> 3325428Speter#include <sys/bus.h> 3425428Speter#include <sys/conf.h> 3525428Speter#include <sys/fcntl.h> 3625428Speter#include <sys/filio.h> 3725428Speter#include <sys/kernel.h> 3825428Speter#include <sys/kthread.h> 3925428Speter#include <sys/lock.h> 4025428Speter#include <sys/malloc.h> 4125428Speter#include <sys/module.h> 4225428Speter#include <sys/mutex.h> 4325428Speter#include <sys/poll.h> 4425428Speter#include <sys/priv.h> 4525428Speter#include <sys/proc.h> 4625428Speter#include <sys/selinfo.h> 4725428Speter#include <sys/uio.h> 4825428Speter#include <sys/unistd.h> 4925428Speter 5025428Speter#include <machine/bus.h> 5125428Speter#include <machine/cpu.h> 5225428Speter 5355205Speter#include <dev/random/randomdev.h> 5425428Speter 5525428Speter#define RANDOM_MINOR 0 5625428Speter 5725428Speterstatic d_close_t random_close; 5825428Speterstatic d_read_t random_read; 5925428Speterstatic d_write_t random_write; 6092725Salfredstatic d_ioctl_t random_ioctl; 6192725Salfredstatic d_poll_t random_poll; 6225428Speter 6325428Speterstatic struct cdevsw random_cdevsw = { 6425428Speter .d_version = D_VERSION, 6525428Speter .d_close = random_close, 6625428Speter .d_read = random_read, 6760938Sjake .d_write = random_write, 6825428Speter .d_ioctl = random_ioctl, 6925428Speter .d_poll = random_poll, 7025428Speter .d_name = "random", 7125428Speter}; 7225428Speter 7325428Speterstruct random_systat random_systat; 7425428Speter 7525428Speter/* For use with make_dev(9)/destroy_dev(9). */ 7625428Speterstatic struct cdev *random_dev; 7725428Speter 7825428Speter/* Used to fake out unused random calls in random_systat */ 7925428Spetervoid 8025428Speterrandom_null_func(void) 8160938Sjake{ 8225428Speter} 8325428Speter 8425428Speter/* ARGSUSED */ 8525428Speterstatic int 8625428Speterrandom_close(struct cdev *dev __unused, int flags, int fmt __unused, 8792725Salfred struct thread *td) 8892725Salfred{ 8925428Speter if ((flags & FWRITE) && (priv_check(td, PRIV_RANDOM_RESEED) == 0) 9045720Speter && (securelevel_gt(td->td_ucred, 0) == 0)) { 9192725Salfred (*random_systat.reseed)(); 9245720Speter random_systat.seeded = 1; 9325428Speter arc4rand(NULL, 0, 1); /* Reseed arc4random as well. */ 9492725Salfred } 9525428Speter 9625428Speter return (0); 9725428Speter} 9825428Speter 9925428Speter/* ARGSUSED */ 10025428Speterstatic int 10192725Salfredrandom_read(struct cdev *dev __unused, struct uio *uio, int flag) 10225428Speter{ 10325428Speter int c, error = 0; 10492725Salfred void *random_buf; 10592725Salfred 10625428Speter /* Blocking logic */ 10755205Speter if (!random_systat.seeded) 10825428Speter error = (*random_systat.block)(flag); 10925428Speter 11025428Speter /* The actual read */ 11125428Speter if (!error) { 11225428Speter 11353649Sjulian random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 11425428Speter 11525428Speter while (uio->uio_resid > 0 && !error) { 116114163Ssam c = MIN(uio->uio_resid, PAGE_SIZE); 117114163Ssam c = (*random_systat.read)(random_buf, c); 11825428Speter error = uiomove(random_buf, c, uio); 11925428Speter } 12025428Speter 12125428Speter free(random_buf, M_TEMP); 12225428Speter 12325428Speter } 12425428Speter 12595702Sphk return (error); 12625428Speter} 12725428Speter 12825428Speter/* ARGSUSED */ 12925428Speterstatic int 13025428Speterrandom_write(struct cdev *dev __unused, struct uio *uio, int flag __unused) 13125428Speter{ 13225428Speter int c, error = 0; 13325428Speter void *random_buf; 13495702Sphk 13595702Sphk random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); 13695702Sphk 13795702Sphk while (uio->uio_resid > 0) { 13895702Sphk c = MIN((int)uio->uio_resid, PAGE_SIZE); 13995702Sphk error = uiomove(random_buf, c, uio); 14095702Sphk if (error) 141133603Stackerman break; 142133603Stackerman (*random_systat.write)(random_buf, c); 143133603Stackerman } 14453649Sjulian 14525428Speter free(random_buf, M_TEMP); 14695702Sphk 14795702Sphk return (error); 14825428Speter} 14925428Speter 15025428Speter/* ARGSUSED */ 15125428Speterstatic int 15225428Speterrandom_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused, 15325428Speter int flags __unused, struct thread *td __unused) 15425428Speter{ 15525428Speter int error = 0; 15695702Sphk 15795702Sphk switch (cmd) { 15825428Speter /* Really handled in upper layer */ 15925428Speter case FIOASYNC: 16025428Speter case FIONBIO: 16195702Sphk break; 16295702Sphk default: 16395702Sphk error = ENOTTY; 16425428Speter } 16525428Speter return (error); 16625428Speter} 16725428Speter 16825428Speter/* ARGSUSED */ 16925428Speterstatic int 17025428Speterrandom_poll(struct cdev *dev __unused, int events, struct thread *td) 17195702Sphk{ 17295702Sphk int revents = 0; 17325428Speter 17425428Speter if (events & (POLLIN | POLLRDNORM)) { 17577217Sphk if (random_systat.seeded) 17677217Sphk revents = events & (POLLIN | POLLRDNORM); 17795702Sphk else 178114163Ssam revents = (*random_systat.poll) (events,td); 17995702Sphk } 18095702Sphk return (revents); 18195702Sphk} 18295702Sphk 18395702Sphk/* ARGSUSED */ 18495702Sphkstatic int 18595702Sphkrandom_modevent(module_t mod __unused, int type, void *data __unused) 186114163Ssam{ 187114163Ssam int error = 0; 188114163Ssam 189114163Ssam switch (type) { 190114163Ssam case MOD_LOAD: 191114163Ssam random_ident_hardware(&random_systat); 192114163Ssam (*random_systat.init)(); 193114163Ssam 194114163Ssam if (bootverbose) 195128195Sfjoe printf("random: <entropy source, %s>\n", 196128195Sfjoe random_systat.ident); 197124543Sonoe 19895702Sphk random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw, 19995702Sphk RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random"); 20096174Simp make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */ 20196174Simp 202114163Ssam break; 203117817Ssam 204124543Sonoe case MOD_UNLOAD: 205114163Ssam (*random_systat.deinit)(); 206124543Sonoe 207124543Sonoe destroy_dev(random_dev); 208124543Sonoe 209124543Sonoe break; 21077217Sphk 21177217Sphk case MOD_SHUTDOWN: 212114232Sharti break; 213114232Sharti 214114232Sharti default: 215114232Sharti error = EOPNOTSUPP; 216114232Sharti break; 217114232Sharti 218114232Sharti } 219114232Sharti return (error); 220114232Sharti} 221114232Sharti 222114232ShartiDEV_MODULE(random, random_modevent, NULL); 223114232ShartiMODULE_VERSION(random, 1); 224125015Sharti