83b1e9e4bb
"dummy" switch priorities, and the users are left with no usable /dev/random. The fix assigns priories to these and gives the users what they want. The override tuneable has a stupid name (blame me!) and this fixes it to be something that 'sysctl kern.random' emits and is the right thing to set. Approved by: re (gjb) Approved by: secteam (cperciva)
300 lines
8.4 KiB
C
300 lines
8.4 KiB
C
/*-
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* Copyright (c) 2000-2013 Mark R V Murray
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* Copyright (c) 2004 Robert N. M. Watson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "opt_random.h"
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#if !defined(RANDOM_YARROW) && !defined(RANDOM_FORTUNA)
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#define RANDOM_YARROW
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#elif defined(RANDOM_YARROW) && defined(RANDOM_FORTUNA)
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#error "Must define either RANDOM_YARROW or RANDOM_FORTUNA"
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#endif
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#if defined(RANDOM_FORTUNA)
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#error "Fortuna is not yet implemented"
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#endif
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/poll.h>
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#include <sys/random.h>
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#include <sys/selinfo.h>
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#include <sys/sysctl.h>
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#include <sys/uio.h>
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#include <sys/unistd.h>
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#include <machine/bus.h>
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#include <machine/cpu.h>
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#include <dev/random/randomdev.h>
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#include <dev/random/randomdev_soft.h>
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#include <dev/random/random_harvestq.h>
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#include <dev/random/random_adaptors.h>
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#if defined(RANDOM_YARROW)
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#include <dev/random/yarrow.h>
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#endif
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#if defined(RANDOM_FORTUNA)
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#include <dev/random/fortuna.h>
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#endif
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static int randomdev_poll(int event, struct thread *td);
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static int randomdev_block(int flag);
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static void randomdev_flush_reseed(void);
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#if defined(RANDOM_YARROW)
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static struct random_adaptor random_context = {
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.ident = "Software, Yarrow",
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.init = randomdev_init,
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.deinit = randomdev_deinit,
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.block = randomdev_block,
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.read = random_yarrow_read,
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.poll = randomdev_poll,
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.reseed = randomdev_flush_reseed,
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.seeded = 0, /* This will be seeded during entropy processing */
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.priority = 90, /* High priority, so top of the list. Fortuna may still win. */
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};
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#define RANDOM_MODULE_NAME yarrow
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#define RANDOM_CSPRNG_NAME "yarrow"
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#endif
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#if defined(RANDOM_FORTUNA)
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static struct random_adaptor random_context = {
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.ident = "Software, Fortuna",
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.init = randomdev_init,
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.deinit = randomdev_deinit,
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.block = randomdev_block,
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.read = random_fortuna_read,
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.poll = randomdev_poll,
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.reseed = randomdev_flush_reseed,
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.seeded = 0, /* This will be excplicitly seeded at startup when secured */
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.priority = 100, /* High priority, so top of the list. Beat Yarrow. */
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};
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#define RANDOM_MODULE_NAME fortuna
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#define RANDOM_CSPRNG_NAME "fortuna"
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#endif
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TUNABLE_INT("kern.random.sys.seeded", &random_context.seeded);
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/* List for the dynamic sysctls */
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static struct sysctl_ctx_list random_clist;
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/* ARGSUSED */
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static int
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random_check_boolean(SYSCTL_HANDLER_ARGS)
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{
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if (oidp->oid_arg1 != NULL && *(u_int *)(oidp->oid_arg1) != 0)
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*(u_int *)(oidp->oid_arg1) = 1;
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return (sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req));
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}
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void
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randomdev_init(void)
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{
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struct sysctl_oid *random_sys_o, *random_sys_harvest_o;
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#if defined(RANDOM_YARROW)
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random_yarrow_init_alg(&random_clist);
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#endif
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#if defined(RANDOM_FORTUNA)
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random_fortuna_init_alg(&random_clist);
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#endif
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random_sys_o = SYSCTL_ADD_NODE(&random_clist,
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SYSCTL_STATIC_CHILDREN(_kern_random),
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OID_AUTO, "sys", CTLFLAG_RW, 0,
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"Entropy Device Parameters");
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SYSCTL_ADD_PROC(&random_clist,
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SYSCTL_CHILDREN(random_sys_o),
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OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW,
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&random_context.seeded, 0, random_check_boolean, "I",
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"Seeded State");
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random_sys_harvest_o = SYSCTL_ADD_NODE(&random_clist,
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SYSCTL_CHILDREN(random_sys_o),
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OID_AUTO, "harvest", CTLFLAG_RW, 0,
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"Entropy Sources");
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SYSCTL_ADD_PROC(&random_clist,
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SYSCTL_CHILDREN(random_sys_harvest_o),
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OID_AUTO, "ethernet", CTLTYPE_INT | CTLFLAG_RW,
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&harvest.ethernet, 1, random_check_boolean, "I",
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"Harvest NIC entropy");
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SYSCTL_ADD_PROC(&random_clist,
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SYSCTL_CHILDREN(random_sys_harvest_o),
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OID_AUTO, "point_to_point", CTLTYPE_INT | CTLFLAG_RW,
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&harvest.point_to_point, 1, random_check_boolean, "I",
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"Harvest serial net entropy");
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SYSCTL_ADD_PROC(&random_clist,
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SYSCTL_CHILDREN(random_sys_harvest_o),
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OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW,
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&harvest.interrupt, 1, random_check_boolean, "I",
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"Harvest IRQ entropy");
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SYSCTL_ADD_PROC(&random_clist,
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SYSCTL_CHILDREN(random_sys_harvest_o),
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OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW,
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&harvest.swi, 1, random_check_boolean, "I",
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"Harvest SWI entropy");
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random_harvestq_init(random_process_event);
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/* Register the randomness harvesting routine */
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randomdev_init_harvester(random_harvestq_internal,
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random_context.read);
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}
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void
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randomdev_deinit(void)
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{
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/* Deregister the randomness harvesting routine */
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randomdev_deinit_harvester();
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/*
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* Command the hash/reseed thread to end and wait for it to finish
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*/
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random_kthread_control = -1;
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tsleep((void *)&random_kthread_control, 0, "term", 0);
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#if defined(RANDOM_YARROW)
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random_yarrow_deinit_alg();
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#endif
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#if defined(RANDOM_FORTUNA)
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random_fortuna_deinit_alg();
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#endif
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sysctl_ctx_free(&random_clist);
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}
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void
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randomdev_unblock(void)
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{
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if (!random_context.seeded) {
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selwakeuppri(&random_context.rsel, PUSER);
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wakeup(&random_context);
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printf("random: unblocking device.\n");
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random_context.seeded = 1;
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}
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/* Do arc4random(9) a favour while we are about it. */
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(void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE,
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ARC4_ENTR_HAVE);
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}
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static int
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randomdev_poll(int events, struct thread *td)
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{
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int revents = 0;
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mtx_lock(&random_reseed_mtx);
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if (random_context.seeded)
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revents = events & (POLLIN | POLLRDNORM);
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else
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selrecord(td, &random_context.rsel);
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mtx_unlock(&random_reseed_mtx);
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return (revents);
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}
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static int
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randomdev_block(int flag)
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{
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int error = 0;
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mtx_lock(&random_reseed_mtx);
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/* Blocking logic */
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while (!random_context.seeded && !error) {
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if (flag & O_NONBLOCK)
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error = EWOULDBLOCK;
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else {
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printf("random: blocking on read.\n");
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error = msleep(&random_context,
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&random_reseed_mtx,
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PUSER | PCATCH, "block", 0);
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}
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}
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mtx_unlock(&random_reseed_mtx);
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return (error);
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}
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/* Helper routine to perform explicit reseeds */
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static void
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randomdev_flush_reseed(void)
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{
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/* Command a entropy queue flush and wait for it to finish */
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random_kthread_control = 1;
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while (random_kthread_control)
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pause("-", hz / 10);
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#if defined(RANDOM_YARROW)
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/* This ultimately calls randomdev_unblock() */
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random_yarrow_reseed();
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#endif
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#if defined(RANDOM_FORTUNA)
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/* This ultimately calls randomdev_unblock() */
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random_fortuna_reseed();
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#endif
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}
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static int
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randomdev_modevent(module_t mod __unused, int type, void *unused __unused)
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{
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switch (type) {
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case MOD_LOAD:
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random_adaptor_register(RANDOM_CSPRNG_NAME, &random_context);
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/*
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* For statically built kernels that contain both device
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* random and options PADLOCK_RNG/RDRAND_RNG/etc..,
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* this event handler will do nothing, since the random
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* driver-specific handlers are loaded after these HW
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* consumers, and hence hasn't yet registered for this event.
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*
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* In case where both the random driver and RNG's are built
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* as seperate modules, random.ko is loaded prior to *_rng.ko's
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* (by dependency). This event handler is there to delay
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* creation of /dev/{u,}random and attachment of this *_rng.ko.
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*/
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EVENTHANDLER_INVOKE(random_adaptor_attach, &random_context);
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return (0);
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}
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return (EINVAL);
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}
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RANDOM_ADAPTOR_MODULE(RANDOM_MODULE_NAME, randomdev_modevent, 1);
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