freebsd-skq/sys/dev/random/randomdev_soft.c
Mark Murray 2a8b87d883 Default to harvesting everything. This is to help give a faster
startup. harvesting can be turned OFF in etc/rc.d/* if it is a
burden.
2004-04-16 17:07:11 +00:00

370 lines
9.7 KiB
C

/*-
* Copyright (c) 2000-2004 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.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/fcntl.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>
#include <dev/random/randomdev_soft.h>
#define RANDOM_FIFO_MAX 256 /* How many events to queue up */
static void random_kthread(void *);
static void
random_harvest_internal(u_int64_t, const void *, u_int,
u_int, u_int, enum esource);
struct random_systat random_yarrow = {
.ident = "Software, Yarrow",
.init = random_yarrow_init,
.deinit = random_yarrow_deinit,
.read = random_yarrow_read,
.write = random_yarrow_write,
.reseed = random_yarrow_reseed,
.seeded = 0,
};
MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers");
/* Lockable FIFO queue holding entropy buffers */
struct entropyfifo {
struct mtx lock;
int count;
STAILQ_HEAD(harvestlist, harvest) head;
};
/* Empty entropy buffers */
static struct entropyfifo emptyfifo;
#define EMPTYBUFFERS 1024
/* Harvested entropy */
static struct entropyfifo harvestfifo[ENTROPYSOURCE];
/* <0 to end the kthread, 0 to let it run */
static int random_kthread_control = 0;
static struct proc *random_kthread_proc;
/* List for the dynamic sysctls */
struct sysctl_ctx_list random_clist;
/* 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);
}
/* ARGSUSED */
void
random_yarrow_init(void)
{
int error, i;
struct harvest *np;
struct sysctl_oid *o, *random_o, *random_sys_o, *random_sys_harvest_o;
enum esource e;
o = SYSCTL_ADD_NODE(&random_clist,
SYSCTL_STATIC_CHILDREN(_kern),
OID_AUTO, "random", CTLFLAG_RW, 0,
"Software Random Number Generator");
random_o = o;
random_yarrow_init_alg(&random_clist, random_o);
o = SYSCTL_ADD_NODE(&random_clist,
SYSCTL_CHILDREN(random_o),
OID_AUTO, "sys", CTLFLAG_RW, 0,
"Entropy Device Parameters");
random_sys_o = o;
o = SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW,
&random_systat.seeded, 0, random_check_boolean, "I",
"Seeded State");
o = SYSCTL_ADD_NODE(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
OID_AUTO, "harvest", CTLFLAG_RW, 0,
"Entropy Sources");
random_sys_harvest_o = o;
o = SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_harvest_o),
OID_AUTO, "ethernet", CTLTYPE_INT | CTLFLAG_RW,
&harvest.ethernet, 1, random_check_boolean, "I",
"Harvest NIC entropy");
o = SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_harvest_o),
OID_AUTO, "point_to_point", CTLTYPE_INT | CTLFLAG_RW,
&harvest.point_to_point, 1, random_check_boolean, "I",
"Harvest serial net entropy");
o = SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_harvest_o),
OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW,
&harvest.interrupt, 1, random_check_boolean, "I",
"Harvest IRQ entropy");
o = SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_harvest_o),
OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW,
&harvest.swi, 0, random_check_boolean, "I",
"Harvest SWI entropy");
/* Initialise the harvest fifos */
STAILQ_INIT(&emptyfifo.head);
emptyfifo.count = 0;
mtx_init(&emptyfifo.lock, "entropy harvest buffers", NULL, MTX_SPIN);
for (i = 0; i < EMPTYBUFFERS; i++) {
np = malloc(sizeof(struct harvest), M_ENTROPY, M_WAITOK);
STAILQ_INSERT_TAIL(&emptyfifo.head, np, next);
}
for (e = RANDOM_START; e < ENTROPYSOURCE; e++) {
STAILQ_INIT(&harvestfifo[e].head);
harvestfifo[e].count = 0;
mtx_init(&harvestfifo[e].lock, "entropy harvest", NULL,
MTX_SPIN);
}
/* Start the hash/reseed thread */
error = kthread_create(random_kthread, NULL,
&random_kthread_proc, RFHIGHPID, 0, "yarrow");
if (error != 0)
panic("Cannot create entropy maintenance thread.");
/* Register the randomness harvesting routine */
random_yarrow_init_harvester(random_harvest_internal,
random_yarrow_read);
}
/* ARGSUSED */
void
random_yarrow_deinit(void)
{
struct harvest *np;
enum esource e;
/* Deregister the randomness harvesting routine */
random_yarrow_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);
/* Destroy the harvest fifos */
while (!STAILQ_EMPTY(&emptyfifo.head)) {
np = STAILQ_FIRST(&emptyfifo.head);
STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
free(np, M_ENTROPY);
}
mtx_destroy(&emptyfifo.lock);
for (e = RANDOM_START; e < ENTROPYSOURCE; e++) {
while (!STAILQ_EMPTY(&harvestfifo[e].head)) {
np = STAILQ_FIRST(&harvestfifo[e].head);
STAILQ_REMOVE_HEAD(&harvestfifo[e].head, next);
free(np, M_ENTROPY);
}
mtx_destroy(&harvestfifo[e].lock);
}
random_yarrow_deinit_alg();
sysctl_ctx_free(&random_clist);
}
/* ARGSUSED */
static void
random_kthread(void *arg __unused)
{
struct harvest *event = NULL;
int found, active;
enum esource source;
/* Process until told to stop */
for (; random_kthread_control == 0;) {
active = 0;
/* Cycle through all the entropy sources */
for (source = RANDOM_START; source < ENTROPYSOURCE; source++) {
found = 0;
/* Lock up queue draining */
mtx_lock_spin(&harvestfifo[source].lock);
if (!STAILQ_EMPTY(&harvestfifo[source].head)) {
/* Get a harvested entropy event */
harvestfifo[source].count--;
event = STAILQ_FIRST(&harvestfifo[source].head);
STAILQ_REMOVE_HEAD(&harvestfifo[source].head,
next);
active = found = 1;
}
/* Unlock the queue */
mtx_unlock_spin(&harvestfifo[source].lock);
/* Deal with the event and dispose of it */
if (found) {
random_process_event(event);
/* Lock the empty event buffer fifo */
mtx_lock_spin(&emptyfifo.lock);
STAILQ_INSERT_TAIL(&emptyfifo.head, event,
next);
mtx_unlock_spin(&emptyfifo.lock);
}
}
/* Found nothing, so don't belabour the issue */
if (!active)
tsleep(&harvestfifo, PUSER, "-", hz / 10);
}
random_set_wakeup_exit(&random_kthread_control);
/* NOTREACHED */
}
/* 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, const void *entropy,
u_int count, u_int bits, u_int frac, enum esource origin)
{
struct harvest *event;
/* Lock the particular fifo */
mtx_lock_spin(&harvestfifo[origin].lock);
/*
* Don't make the harvest queues too big - help to prevent low-grade
* entropy swamping
*/
if (harvestfifo[origin].count < RANDOM_FIFO_MAX) {
/* Lock the empty event buffer fifo */
mtx_lock_spin(&emptyfifo.lock);
if (!STAILQ_EMPTY(&emptyfifo.head)) {
event = STAILQ_FIRST(&emptyfifo.head);
STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
} else
event = NULL;
mtx_unlock_spin(&emptyfifo.lock);
/* If we didn't obtain a buffer, tough */
if (event) {
/* Add the harvested data to the fifo */
harvestfifo[origin].count++;
event->somecounter = somecounter;
event->size = count;
event->bits = bits;
event->frac = frac;
event->source = origin;
/* XXXX Come back and make this dynamic! */
count = MIN(count, HARVESTSIZE);
memcpy(event->entropy, entropy, count);
STAILQ_INSERT_TAIL(&harvestfifo[origin].head,
event, next);
}
}
mtx_unlock_spin(&harvestfifo[origin].lock);
}
void
random_yarrow_write(void *buf, int count)
{
int i;
u_int chunk;
/*
* 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) {
chunk = HARVESTSIZE;
if (i + chunk >= count)
chunk = (u_int)(count - i);
random_harvest_internal(get_cyclecount(), (char *)buf + i,
chunk, 0, 0, RANDOM_WRITE);
}
}
void
random_yarrow_unblock(void)
{
if (!random_systat.seeded) {
random_systat.seeded = 1;
selwakeuppri(&random_systat.rsel, PUSER);
wakeup(&random_systat);
}
}