ddbfa6b19e
* It's not meant to be used in a real system, it's there to show how the basics of how to create interfaces for random_adaptors. Perhaps it should belong in a manual page 2) Move probe.c's functionality in to random_adaptors.c * rename random_ident_hardware() to random_adaptor_choose() 3) Introduce a new way to choose (or select) random_adaptors via tunable "rngs_want" It's a list of comma separated names of adaptors, ordered by preferences. I.e.: rngs_want="yarrow,rdrand" Such setting would cause yarrow to be preferred to rdrand. If neither of them are available (or registered), then system will default to something reasonable (currently yarrow). If yarrow is not present, then we fall back to the adaptor that's first on the list of registered adaptors. 4) Introduce a way where RNGs can play a role of entropy source. This is mostly useful for HW rngs. The way I envision this is that every HW RNG will use this functionality by default. Functionality to disable this is also present. I have an example of how to use this in random_adaptor_example.c (see modload event, and init function) 5) fix kern.random.adaptors from kern.random.adaptors: yarrowpanicblock to kern.random.adaptors: yarrow,panic,block 6) add kern.random.active_adaptor to indicate currently selected adaptor: root@freebsd04:~ # sysctl kern.random.active_adaptor kern.random.active_adaptor: yarrow Submitted by: Arthur Mesh <arthurmesh@gmail.com>
265 lines
6.1 KiB
C
265 lines
6.1 KiB
C
/*-
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* Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
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* Copyright (c) 2000-2004 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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*/
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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/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/module.h>
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#include <sys/mutex.h>
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#include <sys/poll.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/selinfo.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/random_adaptors.h>
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#include <dev/random/randomdev.h>
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#define RANDOM_MINOR 0
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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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static struct cdevsw random_cdevsw = {
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.d_version = D_VERSION,
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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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};
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static struct random_adaptor *random_adaptor;
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static eventhandler_tag attach_tag;
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static int random_inited;
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/* For use with make_dev(9)/destroy_dev(9). */
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static struct cdev *random_dev;
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/* Used to fake out unused random calls in random_adaptor */
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void
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random_null_func(void)
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{
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}
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struct random_adaptor *
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random_get_active_adaptor(void)
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{
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return (random_adaptor);
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}
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/* ARGSUSED */
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static int
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random_close(struct cdev *dev __unused, int flags, int fmt __unused,
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struct thread *td)
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{
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if ((flags & FWRITE) && (priv_check(td, PRIV_RANDOM_RESEED) == 0)
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&& (securelevel_gt(td->td_ucred, 0) == 0)) {
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(*random_adaptor->reseed)();
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random_adaptor->seeded = 1;
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arc4rand(NULL, 0, 1); /* Reseed arc4random as well. */
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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(struct cdev *dev __unused, struct uio *uio, int flag)
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{
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int c, error = 0;
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void *random_buf;
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/* Blocking logic */
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if (!random_adaptor->seeded)
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error = (*random_adaptor->block)(flag);
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/* The actual read */
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if (!error) {
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random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
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while (uio->uio_resid > 0 && !error) {
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c = MIN(uio->uio_resid, PAGE_SIZE);
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c = (*random_adaptor->read)(random_buf, c);
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error = uiomove(random_buf, c, uio);
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}
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free(random_buf, M_TEMP);
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}
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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(struct cdev *dev __unused, struct uio *uio, int flag __unused)
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{
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int c, error = 0;
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void *random_buf;
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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 = MIN((int)uio->uio_resid, 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_adaptor->write)(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(struct cdev *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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int error = 0;
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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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break;
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default:
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error = ENOTTY;
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}
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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_poll(struct cdev *dev __unused, int events, struct thread *td)
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{
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int revents = 0;
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if (events & (POLLIN | POLLRDNORM)) {
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if (random_adaptor->seeded)
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revents = events & (POLLIN | POLLRDNORM);
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else
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revents = (*random_adaptor->poll) (events,td);
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}
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return (revents);
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}
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static void
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random_initialize(void *p, struct random_adaptor *s)
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{
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if (random_inited) {
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printf("random: <%s> already initialized\n",
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random_adaptor->ident);
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return;
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}
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random_adaptor = s;
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(s->init)();
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printf("random: <%s> initialized\n", s->ident);
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random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw,
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RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0666, "random");
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make_dev_alias(random_dev, "urandom"); /* XXX Deprecated */
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/* mark random(4) as initialized, to avoid being called again */
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random_inited = 1;
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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 = 0;
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switch (type) {
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case MOD_LOAD:
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random_adaptor_choose(&random_adaptor);
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if (random_adaptor == NULL) {
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printf(
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"random: No random adaptor attached, postponing initialization\n");
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attach_tag = EVENTHANDLER_REGISTER(random_adaptor_attach,
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random_initialize, NULL, EVENTHANDLER_PRI_ANY);
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} else {
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random_initialize(NULL, random_adaptor);
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}
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break;
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case MOD_UNLOAD:
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if (random_adaptor != NULL) {
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(*random_adaptor->deinit)();
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destroy_dev(random_dev);
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}
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/* Unregister the event handler */
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if (attach_tag != NULL) {
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EVENTHANDLER_DEREGISTER(random_adaptor_attach,
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attach_tag);
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}
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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DEV_MODULE(random, random_modevent, NULL);
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MODULE_VERSION(random, 1);
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