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Olivier Certner
18ce3f50f6
No functional change (intended).
Reviewed by: markj, emaste
Fixes: 3a12982962 ("random: add RDSEED as a provably unique entropy source")
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D60193
169 lines
5.0 KiB
C
169 lines
5.0 KiB
C
/*-
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* Copyright (c) 2013, 2025, David E. O'Brien <[email protected]>
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* Copyright (c) 2013 The FreeBSD Foundation
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* Copyright (c) 2012 Konstantin Belousov <[email protected]>
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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/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/sysctl.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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#define RETRY_COUNT 10
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static u_int random_rdseed_read(void *, u_int);
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static struct random_source random_rdseed = {
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.rs_ident = "Intel Secure Key Seed",
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.rs_source = RANDOM_PURE_RDSEED,
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.rs_read = random_rdseed_read
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};
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SYSCTL_NODE(_kern_random, OID_AUTO, rdseed, CTLFLAG_RW, 0,
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"rdseed (x86) entropy source");
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/* XXX: kern.random.rdseed.enabled=0 also disables RDRAND */
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static bool enabled = true;
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SYSCTL_BOOL(_kern_random_rdseed, OID_AUTO, enabled, CTLFLAG_RDTUN, &enabled, 0,
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"If zero, disable the use of RDSEED.");
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static bool
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x86_rdseed_store(u_long *buf)
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{
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u_long rndval;
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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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"rdseed %1\n\t" /* read randomness into rndval */
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"jc 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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"2:"
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: "+r" (retry), "=r" (rndval) : : "cc");
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*buf = rndval;
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return (retry != 0);
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}
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/* It is required that buf length is a multiple of sizeof(u_long). */
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static u_int
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random_rdseed_read(void *buf, u_int c)
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{
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u_long *b, rndval;
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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 (!x86_rdseed_store(&rndval))
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break;
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*b++ = rndval;
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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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rdseed_modevent(module_t mod, int type, void *unused)
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{
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bool has_rdseed;
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int error = 0;
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has_rdseed = (cpu_stdext_feature & CPUID_STDEXT_RDSEED);
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switch (type) {
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case MOD_LOAD:
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if (has_rdseed && enabled) {
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random_source_register(&random_rdseed);
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printf("random: fast provider: \"%s\"\n", random_rdseed.rs_ident);
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}
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break;
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case MOD_UNLOAD:
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if (has_rdseed)
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random_source_deregister(&random_rdseed);
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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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static moduledata_t rdseed_mod = {
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"rdseed",
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rdseed_modevent,
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0
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};
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DECLARE_MODULE(rdseed, rdseed_mod, SI_SUB_RANDOM, SI_ORDER_FOURTH);
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MODULE_VERSION(rdseed, 1);
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MODULE_DEPEND(rdseed, random_harvestq, 1, 1, 1);
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/*
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* Intel's RDSEED Entropy Assessment Report min-entropy claim is 0.6 Shannons
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* per bit of data output. Rrefer to the following Entropy Source Validation
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* (ESV) certificates:
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*
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* E#87: Junos OS Physical Entropy Source - Broadwell EP 10-Core Die
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* Broadwell-EP-10 FCLGA2011 Intel(R) Xeon(R) E5-2620 V4 Processor
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* https://csrc.nist.gov/projects/cryptographic-module-validation-program/entropy-validations/certificate/87
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* (URLs below omitted for brevity but follow same format.)
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*
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* E#121: Junos OS Physical Entropy Source - Intel Atom C3000 Series
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* (Denverton) 16 Core Die with FCBGA1310 Package
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*
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* E#122: Junos OS Physical Entropy Source - Intel Xeon D-1500 Family
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* (Broadwell) 8 Core Die with FCBGA1667 Package
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*
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* E#123: Junos OS Physical Entropy Source - Intel Xeon D-2100 Series
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* (Skylake) 18 Core Die with FCBGA2518 Package
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*
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* E#141: Junos OS Physical Entropy Source - Intel Xeon D-10 Series
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* (Ice Lake-D-10) Die with FCBGA2227 Package
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*
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* E#169: Junos OS Physical Entropy Source - Intel Xeon AWS-1000 v4 and
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* E5 v4 (Broadwell EP) 15 Core Die with FCLGA2011 Package
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*/
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