252 lines
6.8 KiB
C
252 lines
6.8 KiB
C
/*-
|
|
* Copyright (c) 2013 Arthur Mesh
|
|
* Copyright (c) 2000-2009 Mark R V Murray
|
|
* Copyright (c) 2004 Robert N. M. Watson
|
|
* 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/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/kthread.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/random.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/unistd.h>
|
|
|
|
#include <dev/random/randomdev_soft.h>
|
|
|
|
#include "random_harvestq.h"
|
|
|
|
#define RANDOM_FIFO_MAX 256 /* How many events to queue up */
|
|
|
|
MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers");
|
|
|
|
/*
|
|
* The harvest mutex protects the consistency of the entropy fifos and
|
|
* empty fifo.
|
|
*/
|
|
struct mtx harvest_mtx;
|
|
|
|
/* Lockable FIFO queue holding entropy buffers */
|
|
struct entropyfifo {
|
|
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, 1 to flush the harvest queues */
|
|
int random_kthread_control = 0;
|
|
|
|
static struct proc *random_kthread_proc;
|
|
|
|
static void
|
|
random_kthread(void *arg)
|
|
{
|
|
STAILQ_HEAD(, harvest) local_queue;
|
|
struct harvest *event = NULL;
|
|
int local_count;
|
|
enum esource source;
|
|
event_proc_f func = arg;
|
|
|
|
STAILQ_INIT(&local_queue);
|
|
local_count = 0;
|
|
|
|
/* Process until told to stop */
|
|
mtx_lock_spin(&harvest_mtx);
|
|
for (; random_kthread_control >= 0;) {
|
|
|
|
/* Cycle through all the entropy sources */
|
|
for (source = RANDOM_START; source < ENTROPYSOURCE; source++) {
|
|
/*
|
|
* Drain entropy source records into a thread-local
|
|
* queue for processing while not holding the mutex.
|
|
*/
|
|
STAILQ_CONCAT(&local_queue, &harvestfifo[source].head);
|
|
local_count += harvestfifo[source].count;
|
|
harvestfifo[source].count = 0;
|
|
}
|
|
|
|
/*
|
|
* Deal with events, if any, dropping the mutex as we process
|
|
* each event. Then push the events back into the empty
|
|
* fifo.
|
|
*/
|
|
if (!STAILQ_EMPTY(&local_queue)) {
|
|
mtx_unlock_spin(&harvest_mtx);
|
|
STAILQ_FOREACH(event, &local_queue, next)
|
|
func(event);
|
|
mtx_lock_spin(&harvest_mtx);
|
|
STAILQ_CONCAT(&emptyfifo.head, &local_queue);
|
|
emptyfifo.count += local_count;
|
|
local_count = 0;
|
|
}
|
|
|
|
KASSERT(local_count == 0, ("random_kthread: local_count %d",
|
|
local_count));
|
|
|
|
/*
|
|
* If a queue flush was commanded, it has now happened,
|
|
* and we can mark this by resetting the command.
|
|
*/
|
|
if (random_kthread_control == 1)
|
|
random_kthread_control = 0;
|
|
|
|
/* Work done, so don't belabour the issue */
|
|
msleep_spin_sbt(&random_kthread_control, &harvest_mtx,
|
|
"-", SBT_1S / 10, 0, C_PREL(1));
|
|
|
|
}
|
|
mtx_unlock_spin(&harvest_mtx);
|
|
|
|
random_set_wakeup_exit(&random_kthread_control);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
void
|
|
random_harvestq_init(event_proc_f cb)
|
|
{
|
|
int error, i;
|
|
struct harvest *np;
|
|
enum esource e;
|
|
|
|
/* Initialise the harvest fifos */
|
|
STAILQ_INIT(&emptyfifo.head);
|
|
emptyfifo.count = 0;
|
|
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(&harvest_mtx, "entropy harvest mutex", NULL, MTX_SPIN);
|
|
|
|
|
|
/* Start the hash/reseed thread */
|
|
error = kproc_create(random_kthread, cb,
|
|
&random_kthread_proc, RFHIGHPID, 0, "rand_harvestq"); /* RANDOM_CSPRNG_NAME */
|
|
|
|
if (error != 0)
|
|
panic("Cannot create entropy maintenance thread.");
|
|
}
|
|
|
|
void
|
|
random_harvestq_deinit(void)
|
|
{
|
|
struct harvest *np;
|
|
enum esource e;
|
|
|
|
/* Destroy the harvest fifos */
|
|
while (!STAILQ_EMPTY(&emptyfifo.head)) {
|
|
np = STAILQ_FIRST(&emptyfifo.head);
|
|
STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
|
|
free(np, M_ENTROPY);
|
|
}
|
|
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(&harvest_mtx);
|
|
}
|
|
|
|
/*
|
|
* Entropy harvesting routine. This is supposed to be fast; do
|
|
* not do anything slow in here!
|
|
*/
|
|
void
|
|
random_harvestq_internal(u_int64_t somecounter, const void *entropy,
|
|
u_int count, u_int bits, u_int frac, enum esource origin)
|
|
{
|
|
struct harvest *event;
|
|
|
|
KASSERT(origin >= RANDOM_START && origin <= RANDOM_PURE,
|
|
("random_harvest_internal: origin %d invalid\n", origin));
|
|
|
|
/* Lockless read to avoid lock operations if fifo is full. */
|
|
if (harvestfifo[origin].count >= RANDOM_FIFO_MAX)
|
|
return;
|
|
|
|
mtx_lock_spin(&harvest_mtx);
|
|
|
|
/*
|
|
* Don't make the harvest queues too big - help to prevent low-grade
|
|
* entropy swamping
|
|
*/
|
|
if (harvestfifo[origin].count < RANDOM_FIFO_MAX) {
|
|
event = STAILQ_FIRST(&emptyfifo.head);
|
|
if (event != NULL) {
|
|
/* Add the harvested data to the fifo */
|
|
STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
|
|
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);
|
|
|
|
#if 0
|
|
{
|
|
int i;
|
|
printf("Harvest:%16jX ", event->somecounter);
|
|
for (i = 0; i < event->size; i++)
|
|
printf("%02X", event->entropy[i]);
|
|
for (; i < 16; i++)
|
|
printf(" ");
|
|
printf(" %2d 0x%2X.%03X %02X\n", event->size, event->bits, event->frac, event->source);
|
|
}
|
|
#endif
|
|
|
|
STAILQ_INSERT_TAIL(&harvestfifo[origin].head,
|
|
event, next);
|
|
}
|
|
}
|
|
mtx_unlock_spin(&harvest_mtx);
|
|
}
|
|
|