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freebsd/sys/dev/random/randomdev.c
Poul-Henning Kamp 7ac40f5f59 Gigacommit to improve device-driver source compatibility between
branches:

Initialize struct cdevsw using C99 sparse initializtion and remove
all initializations to default values.

This patch is automatically generated and has been tested by compiling
LINT with all the fields in struct cdevsw in reverse order on alpha,
sparc64 and i386.

Approved by:    re(scottl)
2003-03-03 12:15:54 +00:00

440 lines
11 KiB
C

/*-
* Copyright (c) 2000 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <dev/random/randomdev.h>
static d_open_t random_open;
static d_close_t random_close;
static d_read_t random_read;
static d_write_t random_write;
static d_ioctl_t random_ioctl;
static d_poll_t random_poll;
#define CDEV_MAJOR 2
#define RANDOM_MINOR 3
static struct cdevsw random_cdevsw = {
.d_open = random_open,
.d_close = random_close,
.d_read = random_read,
.d_write = random_write,
.d_ioctl = random_ioctl,
.d_poll = random_poll,
.d_name = "random",
.d_maj = CDEV_MAJOR,
};
static void random_kthread(void *);
static void random_harvest_internal(u_int64_t, void *, u_int, u_int, u_int, enum esource);
static void random_write_internal(void *, int);
/* Ring buffer holding harvested entropy */
static struct harvestring {
volatile u_int head;
volatile u_int tail;
struct harvest data[HARVEST_RING_SIZE];
} harvestring;
static struct random_systat {
u_int seeded; /* 0 causes blocking 1 allows normal output */
u_int burst; /* number of events to do before sleeping */
struct selinfo rsel; /* For poll(2) */
} random_systat;
/* <0 to end the kthread, 0 to let it run */
static int random_kthread_control = 0;
static struct proc *random_kthread_proc;
/* For use with make_dev(9)/destroy_dev(9). */
static dev_t random_dev;
static dev_t urandom_dev;
/* ARGSUSED */
static int
random_check_boolean(SYSCTL_HANDLER_ARGS)
{
if (oidp->oid_arg1 != NULL && *(u_int *)(oidp->oid_arg1) != 0)
*(u_int *)(oidp->oid_arg1) = 1;
return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
}
RANDOM_CHECK_UINT(burst, 0, 20);
SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW,
0, "Random Number Generator");
SYSCTL_NODE(_kern_random, OID_AUTO, sys, CTLFLAG_RW,
0, "Entropy Device Parameters");
SYSCTL_PROC(_kern_random_sys, OID_AUTO, seeded,
CTLTYPE_INT|CTLFLAG_RW, &random_systat.seeded, 1,
random_check_boolean, "I", "Seeded State");
SYSCTL_PROC(_kern_random_sys, OID_AUTO, burst,
CTLTYPE_INT|CTLFLAG_RW, &random_systat.burst, 20,
random_check_uint_burst, "I", "Harvest Burst Size");
SYSCTL_NODE(_kern_random_sys, OID_AUTO, harvest, CTLFLAG_RW,
0, "Entropy Sources");
SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, ethernet,
CTLTYPE_INT|CTLFLAG_RW, &harvest.ethernet, 0,
random_check_boolean, "I", "Harvest NIC entropy");
SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, point_to_point,
CTLTYPE_INT|CTLFLAG_RW, &harvest.point_to_point, 0,
random_check_boolean, "I", "Harvest serial net entropy");
SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, interrupt,
CTLTYPE_INT|CTLFLAG_RW, &harvest.interrupt, 0,
random_check_boolean, "I", "Harvest IRQ entropy");
SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, swi,
CTLTYPE_INT|CTLFLAG_RW, &harvest.swi, 0,
random_check_boolean, "I", "Harvest SWI entropy");
/* ARGSUSED */
static int
random_open(dev_t dev __unused, int flags, int fmt __unused, struct thread *td)
{
int error;
if (flags & FWRITE) {
error = suser(td);
if (error)
return (error);
error = securelevel_gt(td->td_ucred, 0);
if (error)
return (error);
}
return 0;
}
/* ARGSUSED */
static int
random_close(dev_t dev __unused, int flags, int fmt __unused, struct thread *td)
{
if (flags & FWRITE) {
if (!(suser(td) ||
securelevel_gt(td->td_ucred, 0)))
random_reseed();
}
return 0;
}
/* ARGSUSED */
static int
random_read(dev_t dev __unused, struct uio *uio, int flag)
{
int c, ret;
int error = 0;
void *random_buf;
while (!random_systat.seeded) {
if (flag & IO_NDELAY)
error = EWOULDBLOCK;
else
error = tsleep(&random_systat, PUSER|PCATCH,
"block", 0);
if (error != 0)
return error;
}
c = uio->uio_resid < PAGE_SIZE ? uio->uio_resid : PAGE_SIZE;
random_buf = (void *)malloc((u_long)c, M_TEMP, M_WAITOK);
while (uio->uio_resid > 0 && error == 0) {
ret = read_random_real(random_buf, c);
error = uiomove(random_buf, ret, uio);
}
free(random_buf, M_TEMP);
return error;
}
/* ARGSUSED */
static int
random_write(dev_t dev __unused, struct uio *uio, int flag __unused)
{
int c;
int error;
void *random_buf;
error = 0;
random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
while (uio->uio_resid > 0) {
c = (int)(uio->uio_resid < PAGE_SIZE
? uio->uio_resid
: PAGE_SIZE);
error = uiomove(random_buf, c, uio);
if (error)
break;
random_write_internal(random_buf, c);
}
free(random_buf, M_TEMP);
return error;
}
/* ARGSUSED */
static int
random_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused,
int flags __unused, struct thread *td __unused)
{
switch (cmd) {
/* Really handled in upper layer */
case FIOASYNC:
case FIONBIO:
return 0;
default:
return ENOTTY;
}
}
/* ARGSUSED */
static int
random_poll(dev_t dev __unused, int events, struct thread *td)
{
int revents;
revents = 0;
if (events & (POLLIN | POLLRDNORM)) {
if (random_systat.seeded)
revents = events & (POLLIN | POLLRDNORM);
else
selrecord(td, &random_systat.rsel);
}
return revents;
}
/* ARGSUSED */
static int
random_modevent(module_t mod __unused, int type, void *data __unused)
{
int error;
switch(type) {
case MOD_LOAD:
random_init();
/* This can be turned off by the very paranoid
* a reseed will turn it back on.
*/
random_systat.seeded = 1;
/* Number of envents to process off the harvest
* queue before giving it a break and sleeping
*/
random_systat.burst = 20;
/* Initialise the harvest ringbuffer */
harvestring.head = 0;
harvestring.tail = 0;
if (bootverbose)
printf("random: <entropy source>\n");
random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
GID_WHEEL, 0666, "random");
urandom_dev = make_dev_alias(random_dev, "urandom");
/* Start the hash/reseed thread */
error = kthread_create(random_kthread, NULL,
&random_kthread_proc, RFHIGHPID, 0, "random");
if (error != 0)
return error;
/* Register the randomness harvesting routine */
random_init_harvester(random_harvest_internal,
read_random_real);
return 0;
case MOD_UNLOAD:
/* Deregister the randomness harvesting routine */
random_deinit_harvester();
/* Command the hash/reseed thread to end and
* wait for it to finish
*/
random_kthread_control = -1;
tsleep((void *)&random_kthread_control, PUSER, "term", 0);
random_deinit();
destroy_dev(random_dev);
destroy_dev(urandom_dev);
return 0;
case MOD_SHUTDOWN:
return 0;
default:
return EOPNOTSUPP;
}
}
DEV_MODULE(random, random_modevent, NULL);
/* ARGSUSED */
static void
random_kthread(void *arg __unused)
{
struct harvest *event;
u_int newtail, burst;
/* Drain the harvest queue (in 'burst' size chunks,
* if 'burst' > 0. If 'burst' == 0, then completely
* drain the queue.
*/
for (burst = 0; ; burst++) {
if ((harvestring.tail == harvestring.head) ||
(random_systat.burst && burst == random_systat.burst)) {
tsleep(&harvestring, PUSER, "sleep", hz/10);
burst = 0;
}
else {
/* Suck a harvested entropy event out of the queue and
* hand it to the event processor
*/
newtail = (harvestring.tail + 1) & HARVEST_RING_MASK;
event = &harvestring.data[harvestring.tail];
/* Bump the ring counter. This action is assumed
* to be atomic.
*/
harvestring.tail = newtail;
random_process_event(event);
}
/* Is the thread scheduled for a shutdown? */
if (random_kthread_control != 0) {
#ifdef DEBUG
printf("Random kthread setting terminate\n");
#endif
random_set_wakeup_exit(&random_kthread_control);
/* NOTREACHED */
break;
}
}
}
/* Entropy harvesting routine. This is supposed to be fast; do
* not do anything slow in here!
*/
static void
random_harvest_internal(u_int64_t somecounter, void *entropy, u_int count,
u_int bits, u_int frac, enum esource origin)
{
struct harvest *pharvest;
u_int newhead;
newhead = (harvestring.head + 1) & HARVEST_RING_MASK;
if (newhead != harvestring.tail) {
/* Add the harvested data to the ring buffer */
pharvest = &harvestring.data[harvestring.head];
/* Stuff the harvested data into the ring */
pharvest->somecounter = somecounter;
count = count > HARVESTSIZE ? HARVESTSIZE : count;
memcpy(pharvest->entropy, entropy, count);
pharvest->size = count;
pharvest->bits = bits;
pharvest->frac = frac;
pharvest->source =
origin < ENTROPYSOURCE ? origin : RANDOM_START;
/* Bump the ring counter. This action is assumed
* to be atomic.
*/
harvestring.head = newhead;
}
}
static void
random_write_internal(void *buf, int count)
{
int i;
/* Break the input up into HARVESTSIZE chunks.
* The writer has too much control here, so "estimate" the
* the entropy as zero.
*/
for (i = 0; i < count; i += HARVESTSIZE) {
random_harvest_internal(get_cyclecount(), (char *)buf + i,
HARVESTSIZE, 0, 0, RANDOM_WRITE);
}
/* Maybe the loop iterated at least once */
if (i > count)
i -= HARVESTSIZE;
/* Get the last bytes even if the input length is not
* a multiple of HARVESTSIZE.
*/
count %= HARVESTSIZE;
if (count) {
random_harvest_internal(get_cyclecount(), (char *)buf + i,
(u_int)count, 0, 0, RANDOM_WRITE);
}
}
void
random_unblock(void)
{
if (!random_systat.seeded) {
random_systat.seeded = 1;
selwakeup(&random_systat.rsel);
wakeup(&random_systat);
}
}