freebsd-skq/sys/dev/random/randomdev_soft.c
markm b136eed630 Fix the build; Certain linkable symbols need to always be present.
Pass the pointy hat please.

Also unblock the software (Yarrow) generator for now. This will be
reverted; Yarrow needs to block until secure, not this behaviour
of serving as soon as asked.

Folks with specific requiremnts will be able to (can!) unblock this
device with any write, and are encouraged to do so in /etc/rc.d/*
scripting. ("Any" in this case could be "echo '' > /dev/random" as
root).
2013-09-07 22:07:36 +00:00

308 lines
8.2 KiB
C

/*-
* Copyright (c) 2000-2013 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.
*
*/
#if !defined(YARROW_RNG) && !defined(FORTUNA_RNG)
#define YARROW_RNG
#elif defined(YARROW_RNG) && defined(FORTUNA_RNG)
#error "Must define either YARROW_RNG or FORTUNA_RNG"
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/random.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <dev/random/random_adaptors.h>
#include <dev/random/randomdev.h>
#include <dev/random/randomdev_soft.h>
#if defined(YARROW_RNG)
#include <dev/random/yarrow.h>
#endif
#if defined(FORTUNA_RNG)
#include <dev/random/fortuna.h>
#endif
#include "random_harvestq.h"
static int randomdev_poll(int event, struct thread *td);
static int randomdev_block(int flag);
static void randomdev_flush_reseed(void);
#if defined(YARROW_RNG)
static struct random_adaptor random_context = {
.ident = "Software, Yarrow",
.init = randomdev_init,
.deinit = randomdev_deinit,
.block = randomdev_block,
.read = random_yarrow_read,
.write = randomdev_write,
.poll = randomdev_poll,
.reseed = randomdev_flush_reseed,
.seeded = 1,
};
#define RANDOM_MODULE_NAME yarrow
#define RANDOM_CSPRNG_NAME "yarrow"
#endif
#if defined(FORTUNA_RNG)
static struct random_adaptor random_context = {
.ident = "Software, Fortuna",
.init = randomdev_init,
.deinit = randomdev_deinit,
.block = randomdev_block,
.read = random_fortuna_read,
.write = randomdev_write,
.poll = randomdev_poll,
.reseed = randomdev_flush_reseed,
.seeded = 1,
};
#define RANDOM_MODULE_NAME fortuna
#define RANDOM_CSPRNG_NAME "fortuna"
#endif
/* List for the dynamic sysctls */
static 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);
}
void
randomdev_init(void)
{
struct sysctl_oid *random_sys_o, *random_sys_harvest_o;
#if defined(YARROW_RNG)
random_yarrow_init_alg(&random_clist);
#endif
#if defined(FORTUNA_RNG)
random_fortuna_init_alg(&random_clist);
#endif
random_sys_o = SYSCTL_ADD_NODE(&random_clist,
SYSCTL_STATIC_CHILDREN(_kern_random),
OID_AUTO, "sys", CTLFLAG_RW, 0,
"Entropy Device Parameters");
SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW,
&random_context.seeded, 1, random_check_boolean, "I",
"Seeded State");
random_sys_harvest_o = SYSCTL_ADD_NODE(&random_clist,
SYSCTL_CHILDREN(random_sys_o),
OID_AUTO, "harvest", CTLFLAG_RW, 0,
"Entropy Sources");
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");
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");
SYSCTL_ADD_PROC(&random_clist,
SYSCTL_CHILDREN(random_sys_harvest_o),
OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW,
&harvest.interrupt, 0, random_check_boolean, "I",
"Harvest IRQ entropy");
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");
random_harvestq_init(random_process_event);
/* Register the randomness harvesting routine */
randomdev_init_harvester(random_harvestq_internal,
random_context.read);
}
void
randomdev_deinit(void)
{
/* Deregister the randomness harvesting routine */
randomdev_deinit_harvester();
/*
* Command the hash/reseed thread to end and wait for it to finish
*/
random_kthread_control = -1;
tsleep((void *)&random_kthread_control, 0, "term", 0);
#if defined(YARROW_RNG)
random_yarrow_deinit_alg();
#endif
#if defined(FORTUNA_RNG)
random_fortuna_deinit_alg();
#endif
sysctl_ctx_free(&random_clist);
}
void
randomdev_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 entropy as zero.
*/
for (i = 0; i < count; i += HARVESTSIZE) {
chunk = HARVESTSIZE;
if (i + chunk >= count)
chunk = (u_int)(count - i);
random_harvestq_internal(get_cyclecount(), (char *)buf + i,
chunk, 0, 0, RANDOM_WRITE);
}
}
void
randomdev_unblock(void)
{
if (!random_context.seeded) {
random_context.seeded = 1;
selwakeuppri(&random_context.rsel, PUSER);
wakeup(&random_context);
}
(void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE,
ARC4_ENTR_HAVE);
}
static int
randomdev_poll(int events, struct thread *td)
{
int revents = 0;
mtx_lock(&random_reseed_mtx);
if (random_context.seeded)
revents = events & (POLLIN | POLLRDNORM);
else
selrecord(td, &random_context.rsel);
mtx_unlock(&random_reseed_mtx);
return revents;
}
static int
randomdev_block(int flag)
{
int error = 0;
mtx_lock(&random_reseed_mtx);
/* Blocking logic */
while (!random_context.seeded && !error) {
if (flag & O_NONBLOCK)
error = EWOULDBLOCK;
else {
printf("Entropy device is blocking.\n");
error = msleep(&random_context,
&random_reseed_mtx,
PUSER | PCATCH, "block", 0);
}
}
mtx_unlock(&random_reseed_mtx);
return error;
}
/* Helper routine to perform explicit reseeds */
static void
randomdev_flush_reseed(void)
{
/* Command a entropy queue flush and wait for it to finish */
random_kthread_control = 1;
while (random_kthread_control)
pause("-", hz / 10);
#if defined(YARROW_RNG)
random_yarrow_reseed();
#endif
#if defined(FORTUNA_RNG)
random_fortuna_reseed();
#endif
}
static int
randomdev_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
random_adaptor_register(RANDOM_CSPRNG_NAME, &random_context);
/*
* For statically built kernels that contain both device
* random and options PADLOCK_RNG/RDRAND_RNG/etc..,
* this event handler will do nothing, since the random
* driver-specific handlers are loaded after these HW
* consumers, and hence hasn't yet registered for this event.
*
* In case where both the random driver and RNG's are built
* as seperate modules, random.ko is loaded prior to *_rng.ko's
* (by dependency). This event handler is there to delay
* creation of /dev/{u,}random and attachment of this *_rng.ko.
*/
EVENTHANDLER_INVOKE(random_adaptor_attach, &random_context);
return (0);
}
return (EINVAL);
}
RANDOM_ADAPTOR_MODULE(RANDOM_MODULE_NAME, randomdev_modevent, 1);