440 lines
11 KiB
C
440 lines
11 KiB
C
/*-
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* Copyright (c) 2000 Mark R V Murray
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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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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/filio.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/poll.h>
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#include <sys/proc.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 <sys/vnode.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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static d_open_t random_open;
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static d_close_t random_close;
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static d_read_t random_read;
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static d_write_t random_write;
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static d_ioctl_t random_ioctl;
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static d_poll_t random_poll;
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#define CDEV_MAJOR 2
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#define RANDOM_MINOR 3
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static struct cdevsw random_cdevsw = {
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.d_open = random_open,
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.d_close = random_close,
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.d_read = random_read,
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.d_write = random_write,
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.d_ioctl = random_ioctl,
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.d_poll = random_poll,
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.d_name = "random",
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.d_maj = CDEV_MAJOR,
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};
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static void random_kthread(void *);
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static void random_harvest_internal(u_int64_t, void *, u_int, u_int, u_int, enum esource);
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static void random_write_internal(void *, int);
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/* Ring buffer holding harvested entropy */
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static struct harvestring {
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volatile u_int head;
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volatile u_int tail;
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struct harvest data[HARVEST_RING_SIZE];
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} harvestring;
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static struct random_systat {
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u_int seeded; /* 0 causes blocking 1 allows normal output */
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u_int burst; /* number of events to do before sleeping */
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struct selinfo rsel; /* For poll(2) */
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} random_systat;
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/* <0 to end the kthread, 0 to let it run */
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static int random_kthread_control = 0;
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static struct proc *random_kthread_proc;
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/* For use with make_dev(9)/destroy_dev(9). */
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static dev_t random_dev;
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static dev_t urandom_dev;
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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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RANDOM_CHECK_UINT(burst, 0, 20);
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SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW,
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0, "Random Number Generator");
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SYSCTL_NODE(_kern_random, OID_AUTO, sys, CTLFLAG_RW,
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0, "Entropy Device Parameters");
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SYSCTL_PROC(_kern_random_sys, OID_AUTO, seeded,
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CTLTYPE_INT|CTLFLAG_RW, &random_systat.seeded, 1,
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random_check_boolean, "I", "Seeded State");
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SYSCTL_PROC(_kern_random_sys, OID_AUTO, burst,
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CTLTYPE_INT|CTLFLAG_RW, &random_systat.burst, 20,
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random_check_uint_burst, "I", "Harvest Burst Size");
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SYSCTL_NODE(_kern_random_sys, OID_AUTO, harvest, CTLFLAG_RW,
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0, "Entropy Sources");
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SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, ethernet,
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CTLTYPE_INT|CTLFLAG_RW, &harvest.ethernet, 0,
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random_check_boolean, "I", "Harvest NIC entropy");
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SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, point_to_point,
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CTLTYPE_INT|CTLFLAG_RW, &harvest.point_to_point, 0,
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random_check_boolean, "I", "Harvest serial net entropy");
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SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, interrupt,
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CTLTYPE_INT|CTLFLAG_RW, &harvest.interrupt, 0,
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random_check_boolean, "I", "Harvest IRQ entropy");
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SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, swi,
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CTLTYPE_INT|CTLFLAG_RW, &harvest.swi, 0,
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random_check_boolean, "I", "Harvest SWI entropy");
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/* ARGSUSED */
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static int
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random_open(dev_t dev __unused, int flags, int fmt __unused, struct thread *td)
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{
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int error;
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if (flags & FWRITE) {
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error = suser(td);
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if (error)
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return (error);
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error = securelevel_gt(td->td_ucred, 0);
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if (error)
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return (error);
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}
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return 0;
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}
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/* ARGSUSED */
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static int
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random_close(dev_t dev __unused, int flags, int fmt __unused, struct thread *td)
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{
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if (flags & FWRITE) {
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if (!(suser(td) ||
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securelevel_gt(td->td_ucred, 0)))
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random_reseed();
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}
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return 0;
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}
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/* ARGSUSED */
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static int
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random_read(dev_t dev __unused, struct uio *uio, int flag)
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{
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int c, ret;
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int error = 0;
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void *random_buf;
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while (!random_systat.seeded) {
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if (flag & IO_NDELAY)
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error = EWOULDBLOCK;
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else
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error = tsleep(&random_systat, PUSER|PCATCH,
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"block", 0);
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if (error != 0)
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return error;
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}
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c = uio->uio_resid < PAGE_SIZE ? uio->uio_resid : PAGE_SIZE;
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random_buf = (void *)malloc((u_long)c, M_TEMP, M_WAITOK);
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while (uio->uio_resid > 0 && error == 0) {
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ret = read_random_real(random_buf, c);
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error = uiomove(random_buf, ret, uio);
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}
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free(random_buf, M_TEMP);
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return error;
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}
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/* ARGSUSED */
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static int
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random_write(dev_t dev __unused, struct uio *uio, int flag __unused)
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{
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int c;
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int error;
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void *random_buf;
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error = 0;
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random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
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while (uio->uio_resid > 0) {
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c = (int)(uio->uio_resid < PAGE_SIZE
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? uio->uio_resid
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: PAGE_SIZE);
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error = uiomove(random_buf, c, uio);
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if (error)
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break;
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random_write_internal(random_buf, c);
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}
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free(random_buf, M_TEMP);
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return error;
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}
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/* ARGSUSED */
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static int
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random_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused,
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int flags __unused, struct thread *td __unused)
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{
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switch (cmd) {
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/* Really handled in upper layer */
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case FIOASYNC:
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case FIONBIO:
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return 0;
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default:
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return ENOTTY;
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}
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}
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/* ARGSUSED */
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static int
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random_poll(dev_t dev __unused, int events, struct thread *td)
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{
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int revents;
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revents = 0;
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if (events & (POLLIN | POLLRDNORM)) {
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if (random_systat.seeded)
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revents = events & (POLLIN | POLLRDNORM);
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else
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selrecord(td, &random_systat.rsel);
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}
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return revents;
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}
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/* ARGSUSED */
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static int
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random_modevent(module_t mod __unused, int type, void *data __unused)
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{
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int error;
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switch(type) {
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case MOD_LOAD:
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random_init();
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/* This can be turned off by the very paranoid
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* a reseed will turn it back on.
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*/
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random_systat.seeded = 1;
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/* Number of envents to process off the harvest
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* queue before giving it a break and sleeping
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*/
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random_systat.burst = 20;
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/* Initialise the harvest ringbuffer */
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harvestring.head = 0;
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harvestring.tail = 0;
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if (bootverbose)
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printf("random: <entropy source>\n");
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random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
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GID_WHEEL, 0666, "random");
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urandom_dev = make_dev_alias(random_dev, "urandom");
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/* Start the hash/reseed thread */
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error = kthread_create(random_kthread, NULL,
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&random_kthread_proc, RFHIGHPID, 0, "random");
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if (error != 0)
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return error;
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/* Register the randomness harvesting routine */
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random_init_harvester(random_harvest_internal,
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read_random_real);
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return 0;
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case MOD_UNLOAD:
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/* Deregister the randomness harvesting routine */
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random_deinit_harvester();
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/* Command the hash/reseed thread to end and
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* 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, PUSER, "term", 0);
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random_deinit();
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destroy_dev(random_dev);
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destroy_dev(urandom_dev);
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return 0;
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case MOD_SHUTDOWN:
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return 0;
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default:
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return EOPNOTSUPP;
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}
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}
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DEV_MODULE(random, random_modevent, NULL);
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/* ARGSUSED */
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static void
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random_kthread(void *arg __unused)
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{
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struct harvest *event;
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u_int newtail, burst;
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/* Drain the harvest queue (in 'burst' size chunks,
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* if 'burst' > 0. If 'burst' == 0, then completely
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* drain the queue.
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*/
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for (burst = 0; ; burst++) {
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if ((harvestring.tail == harvestring.head) ||
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(random_systat.burst && burst == random_systat.burst)) {
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tsleep(&harvestring, PUSER, "-", hz/10);
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burst = 0;
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}
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else {
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/* Suck a harvested entropy event out of the queue and
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* hand it to the event processor
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*/
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newtail = (harvestring.tail + 1) & HARVEST_RING_MASK;
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event = &harvestring.data[harvestring.tail];
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/* Bump the ring counter. This action is assumed
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* to be atomic.
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*/
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harvestring.tail = newtail;
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random_process_event(event);
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}
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/* Is the thread scheduled for a shutdown? */
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if (random_kthread_control != 0) {
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#ifdef DEBUG
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printf("Random kthread setting terminate\n");
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#endif
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random_set_wakeup_exit(&random_kthread_control);
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/* NOTREACHED */
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break;
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}
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}
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}
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/* Entropy harvesting routine. This is supposed to be fast; do
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* not do anything slow in here!
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*/
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static void
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random_harvest_internal(u_int64_t somecounter, void *entropy, u_int count,
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u_int bits, u_int frac, enum esource origin)
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{
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struct harvest *pharvest;
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u_int newhead;
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newhead = (harvestring.head + 1) & HARVEST_RING_MASK;
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if (newhead != harvestring.tail) {
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/* Add the harvested data to the ring buffer */
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pharvest = &harvestring.data[harvestring.head];
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/* Stuff the harvested data into the ring */
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pharvest->somecounter = somecounter;
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count = count > HARVESTSIZE ? HARVESTSIZE : count;
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memcpy(pharvest->entropy, entropy, count);
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pharvest->size = count;
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pharvest->bits = bits;
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pharvest->frac = frac;
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pharvest->source =
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origin < ENTROPYSOURCE ? origin : RANDOM_START;
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/* Bump the ring counter. This action is assumed
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* to be atomic.
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*/
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harvestring.head = newhead;
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}
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}
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static void
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random_write_internal(void *buf, int count)
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{
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int i;
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/* Break the input up into HARVESTSIZE chunks.
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* The writer has too much control here, so "estimate" the
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* the entropy as zero.
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*/
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for (i = 0; i < count; i += HARVESTSIZE) {
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random_harvest_internal(get_cyclecount(), (char *)buf + i,
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HARVESTSIZE, 0, 0, RANDOM_WRITE);
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}
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/* Maybe the loop iterated at least once */
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if (i > count)
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i -= HARVESTSIZE;
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/* Get the last bytes even if the input length is not
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* a multiple of HARVESTSIZE.
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*/
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count %= HARVESTSIZE;
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if (count) {
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random_harvest_internal(get_cyclecount(), (char *)buf + i,
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(u_int)count, 0, 0, RANDOM_WRITE);
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}
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}
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void
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random_unblock(void)
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{
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if (!random_systat.seeded) {
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random_systat.seeded = 1;
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selwakeup(&random_systat.rsel);
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wakeup(&random_systat);
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}
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}
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