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138 lines
3.7 KiB
C
138 lines
3.7 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/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/selinfo.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_harvestq.h>
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#include <dev/random/live_entropy_sources.h>
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#include <dev/random/random_adaptors.h>
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#define RETRY_COUNT 10
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static int random_ivy_read(void *, int);
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static struct random_hardware_source random_ivy = {
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.ident = "Hardware, Intel Secure Key RNG",
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.source = RANDOM_PURE_RDRAND,
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.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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static int
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random_ivy_read(void *buf, int c)
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{
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long *b;
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int count;
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KASSERT(c % sizeof(long) == 0, ("partial read %d", c));
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for (b = buf, count = c; count > 0; count -= sizeof(long), 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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else
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#ifndef KLD_MODULE
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if (bootverbose)
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#endif
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printf("%s: RDRAND is not present\n",
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random_ivy.ident);
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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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LIVE_ENTROPY_SRC_MODULE(random_rdrand, rdrand_modevent, 1);
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