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/*-
* Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
* Copyright (c) 2013 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/param.h>
__FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/unistd.h>
#include <machine/cpu.h>
#include <dev/random/randomdev.h>
#include <dev/random/randomdev_soft.h>
#include <dev/random/random_adaptors.h>
#include <dev/random/random_harvestq.h>
#include "live_entropy_sources.h"
LIST_HEAD(les_head, live_entropy_sources);
static struct les_head sources = LIST_HEAD_INITIALIZER(sources);
/*
* The live_lock protects the consistency of the "struct les_head sources"
*/
static struct sx les_lock; /* need a sleepable lock */
void
live_entropy_source_register(struct random_hardware_source *rsource)
{
struct live_entropy_sources *les;
KASSERT(rsource != NULL, ("invalid input to %s", __func__));
les = malloc(sizeof(struct live_entropy_sources), M_ENTROPY, M_WAITOK);
les->rsource = rsource;
sx_xlock(&les_lock);
LIST_INSERT_HEAD(&sources, les, entries);
sx_xunlock(&les_lock);
}
void
live_entropy_source_deregister(struct random_hardware_source *rsource)
{
struct live_entropy_sources *les = NULL;
KASSERT(rsource != NULL, ("invalid input to %s", __func__));
sx_xlock(&les_lock);
LIST_FOREACH(les, &sources, entries)
if (les->rsource == rsource) {
LIST_REMOVE(les, entries);
break;
}
sx_xunlock(&les_lock);
if (les != NULL)
free(les, M_ENTROPY);
}
static int
live_entropy_source_handler(SYSCTL_HANDLER_ARGS)
{
struct live_entropy_sources *les;
int error, count;
count = error = 0;
sx_slock(&les_lock);
if (LIST_EMPTY(&sources))
error = SYSCTL_OUT(req, "", 0);
else {
LIST_FOREACH(les, &sources, entries) {
error = SYSCTL_OUT(req, ",", count++ ? 1 : 0);
if (error)
break;
error = SYSCTL_OUT(req, les->rsource->ident, strlen(les->rsource->ident));
if (error)
break;
}
}
sx_sunlock(&les_lock);
return (error);
}
static void
live_entropy_sources_init(void *unused)
{
SYSCTL_PROC(_kern_random, OID_AUTO, live_entropy_sources,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
NULL, 0, live_entropy_source_handler, "",
"List of Active Live Entropy Sources");
sx_init(&les_lock, "live_entropy_sources");
}
/*
* Run through all "live" sources reading entropy for the given
* number of rounds, which should be a multiple of the number
* of entropy accumulation pools in use; 2 for Yarrow and 32
* for Fortuna.
*
* BEWARE!!!
* This function runs inside the RNG thread! Don't do anything silly!
* Remember that we are NOT holding harvest_mtx on entry!
*/
void
live_entropy_sources_feed(int rounds, event_proc_f entropy_processor)
{
static struct harvest event;
static uint8_t buf[HARVESTSIZE];
struct live_entropy_sources *les;
int i, n;
sx_slock(&les_lock);
/*
* Walk over all of live entropy sources, and feed their output
* to the system-wide RNG.
*/
LIST_FOREACH(les, &sources, entries) {
for (i = 0; i < rounds; i++) {
/*
* This should be quick, since it's a live entropy
* source.
*/
/* FIXME: Whine loudly if this didn't work. */
n = les->rsource->read(buf, sizeof(buf));
n = MIN(n, HARVESTSIZE);
event.somecounter = get_cyclecount();
event.size = n;
event.bits = (n*8)/2;
event.source = les->rsource->source;
memcpy(event.entropy, buf, n);
/* Do the actual entropy insertion */
entropy_processor(&event);
}
}
sx_sunlock(&les_lock);
}
static void
live_entropy_sources_deinit(void *unused)
{
sx_destroy(&les_lock);
}
SYSINIT(random_adaptors, SI_SUB_RANDOM, SI_ORDER_FIRST,
live_entropy_sources_init, NULL);
SYSUNINIT(random_adaptors, SI_SUB_RANDOM, SI_ORDER_FIRST,
live_entropy_sources_deinit, NULL);
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