6895cade94
Refer to discussion in PR 230808 for a less incomplete discussion, but the gist of this change is that we currently collect orders of magnitude more entropy than we need. The excess comes from bytes being read out of /dev/*random. The default rate at which we collect entropy without the read_rate increase is already more than we need to recover from a compromise of an internal state. Reviewed by: #csprng (cem, delphij, markm) Differential Revision: https://reviews.freebsd.org/D32021
50 lines
2.3 KiB
C
50 lines
2.3 KiB
C
/*-
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* Copyright (c) 2013-2015, 2017 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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#ifndef SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED
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#define SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED
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#define HARVESTSIZE 2 /* Max length in words of each harvested entropy unit */
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/* These are used to queue harvested packets of entropy. The entropy
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* buffer size is pretty arbitrary.
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*/
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struct harvest_event {
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uint32_t he_somecounter; /* fast counter for clock jitter */
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uint32_t he_entropy[HARVESTSIZE];/* some harvested entropy */
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uint8_t he_size; /* harvested entropy byte count */
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uint8_t he_destination; /* destination pool of this entropy */
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uint8_t he_source; /* origin of the entropy */
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};
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#define RANDOM_HARVEST_INIT_LOCK(x) mtx_init(&harvest_context.hc_mtx, "entropy harvest mutex", NULL, MTX_SPIN)
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#define RANDOM_HARVEST_LOCK(x) mtx_lock_spin(&harvest_context.hc_mtx)
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#define RANDOM_HARVEST_UNLOCK(x) mtx_unlock_spin(&harvest_context.hc_mtx)
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#endif /* SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED */
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