10cb24248a
This code has had an extensive rewrite and a good series of reviews, both by the author and other parties. This means a lot of code has been simplified. Pluggable structures for high-rate entropy generators are available, and it is most definitely not the case that /dev/random can be driven by only a hardware souce any more. This has been designed out of the device. Hardware sources are stirred into the CSPRNG (Yarrow, Fortuna) like any other entropy source. Pluggable modules may be written by third parties for additional sources. The harvesting structures and consequently the locking have been simplified. Entropy harvesting is done in a more general way (the documentation for this will follow). There is some GREAT entropy to be had in the UMA allocator, but it is disabled for now as messing with that is likely to annoy many people. The venerable (but effective) Yarrow algorithm, which is no longer supported by its authors now has an alternative, Fortuna. For now, Yarrow is retained as the default algorithm, but this may be changed using a kernel option. It is intended to make Fortuna the default algorithm for 11.0. Interested parties are encouraged to read ISBN 978-0-470-47424-2 "Cryptography Engineering" By Ferguson, Schneier and Kohno for Fortuna's gory details. Heck, read it anyway. Many thanks to Arthur Mesh who did early grunt work, and who got caught in the crossfire rather more than he deserved to. My thanks also to folks who helped me thresh this out on whiteboards and in the odd "Hallway track", or otherwise. My Nomex pants are on. Let the feedback commence! Reviewed by: trasz,des(partial),imp(partial?),rwatson(partial?) Approved by: so(des)
137 lines
3.8 KiB
C
137 lines
3.8 KiB
C
/*-
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* Copyright (c) 2013 The FreeBSD Foundation
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* Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
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* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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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/kernel.h>
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#include <sys/conf.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/random.h>
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#include <sys/systm.h>
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#include <machine/md_var.h>
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#include <machine/specialreg.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_adaptors.h>
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#include <dev/random/live_entropy_sources.h>
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#define RETRY_COUNT 10
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static u_int random_ivy_read(void *, u_int);
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static struct live_entropy_source random_ivy = {
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.les_ident = "Intel Secure Key RNG",
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.les_source = RANDOM_PURE_RDRAND,
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.les_read = random_ivy_read
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};
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static inline int
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ivy_rng_store(long *buf)
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{
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#ifdef __GNUCLIKE_ASM
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long tmp;
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int retry;
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retry = RETRY_COUNT;
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__asm __volatile(
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"1:\n\t"
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"rdrand %2\n\t" /* read randomness into tmp */
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"jb 2f\n\t" /* CF is set on success, exit retry loop */
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"dec %0\n\t" /* otherwise, retry-- */
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"jne 1b\n\t" /* and loop if retries are not exhausted */
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"jmp 3f\n" /* failure, retry is 0, used as return value */
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"2:\n\t"
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"mov %2,%1\n\t" /* *buf = tmp */
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"3:"
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: "+q" (retry), "=m" (*buf), "+q" (tmp) : : "cc");
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return (retry);
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#else /* __GNUCLIKE_ASM */
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return (0);
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#endif
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}
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/* It is specifically allowed that buf is a multiple of sizeof(long) */
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static u_int
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random_ivy_read(void *buf, u_int c)
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{
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long *b;
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u_int count;
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KASSERT(c % sizeof(*b) == 0, ("partial read %d", c));
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b = buf;
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for (count = c; count > 0; count -= sizeof(*b)) {
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if (ivy_rng_store(b++) == 0)
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break;
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}
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return (c - count);
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}
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static int
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rdrand_modevent(module_t mod, int type, void *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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if (cpu_feature2 & CPUID2_RDRAND) {
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live_entropy_source_register(&random_ivy);
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printf("random: live provider: \"%s\"\n", random_ivy.les_ident);
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}
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break;
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case MOD_UNLOAD:
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if (cpu_feature2 & CPUID2_RDRAND)
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live_entropy_source_deregister(&random_ivy);
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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(rdrand, rdrand_modevent, NULL);
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MODULE_VERSION(rdrand, 1);
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MODULE_DEPEND(rdrand, random_adaptors, 1, 1, 1);
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