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* GENERAL - Update copyright. - Make kernel options for RANDOM_YARROW and RANDOM_DUMMY. Set neither to ON, which means we want Fortuna - If there is no 'device random' in the kernel, there will be NO random(4) device in the kernel, and the KERN_ARND sysctl will return nothing. With RANDOM_DUMMY there will be a random(4) that always blocks. - Repair kern.arandom (KERN_ARND sysctl). The old version went through arc4random(9) and was a bit weird. - Adjust arc4random stirring a bit - the existing code looks a little suspect. - Fix the nasty pre- and post-read overloading by providing explictit functions to do these tasks. - Redo read_random(9) so as to duplicate random(4)'s read internals. This makes it a first-class citizen rather than a hack. - Move stuff out of locked regions when it does not need to be there. - Trim RANDOM_DEBUG printfs. Some are excess to requirement, some behind boot verbose. - Use SYSINIT to sequence the startup. - Fix init/deinit sysctl stuff. - Make relevant sysctls also tunables. - Add different harvesting "styles" to allow for different requirements (direct, queue, fast). - Add harvesting of FFS atime events. This needs to be checked for weighing down the FS code. - Add harvesting of slab allocator events. This needs to be checked for weighing down the allocator code. - Fix the random(9) manpage. - Loadable modules are not present for now. These will be re-engineered when the dust settles. - Use macros for locks. - Fix comments. * src/share/man/... - Update the man pages. * src/etc/... - The startup/shutdown work is done in D2924. * src/UPDATING - Add UPDATING announcement. * src/sys/dev/random/build.sh - Add copyright. - Add libz for unit tests. * src/sys/dev/random/dummy.c - Remove; no longer needed. Functionality incorporated into randomdev.*. * live_entropy_sources.c live_entropy_sources.h - Remove; content moved. - move content to randomdev.[ch] and optimise. * src/sys/dev/random/random_adaptors.c src/sys/dev/random/random_adaptors.h - Remove; plugability is no longer used. Compile-time algorithm selection is the way to go. * src/sys/dev/random/random_harvestq.c src/sys/dev/random/random_harvestq.h - Add early (re)boot-time randomness caching. * src/sys/dev/random/randomdev_soft.c src/sys/dev/random/randomdev_soft.h - Remove; no longer needed. * src/sys/dev/random/uint128.h - Provide a fake uint128_t; if a real one ever arrived, we can use that instead. All that is needed here is N=0, N++, N==0, and some localised trickery is used to manufacture a 128-bit 0ULLL. * src/sys/dev/random/unit_test.c src/sys/dev/random/unit_test.h - Improve unit tests; previously the testing human needed clairvoyance; now the test will do a basic check of compressibility. Clairvoyant talent is still a good idea. - This is still a long way off a proper unit test. * src/sys/dev/random/fortuna.c src/sys/dev/random/fortuna.h - Improve messy union to just uint128_t. - Remove unneeded 'static struct fortuna_start_cache'. - Tighten up up arithmetic. - Provide a method to allow eternal junk to be introduced; harden it against blatant by compress/hashing. - Assert that locks are held correctly. - Fix the nasty pre- and post-read overloading by providing explictit functions to do these tasks. - Turn into self-sufficient module (no longer requires randomdev_soft.[ch]) * src/sys/dev/random/yarrow.c src/sys/dev/random/yarrow.h - Improve messy union to just uint128_t. - Remove unneeded 'staic struct start_cache'. - Tighten up up arithmetic. - Provide a method to allow eternal junk to be introduced; harden it against blatant by compress/hashing. - Assert that locks are held correctly. - Fix the nasty pre- and post-read overloading by providing explictit functions to do these tasks. - Turn into self-sufficient module (no longer requires randomdev_soft.[ch]) - Fix some magic numbers elsewhere used as FAST and SLOW. Differential Revision: https://reviews.freebsd.org/D2025 Reviewed by: vsevolod,delphij,rwatson,trasz,jmg Approved by: so (delphij)
148 lines
3.6 KiB
Groff
148 lines
3.6 KiB
Groff
.\"
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.\" Copyright (c) 2002-2015 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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.\" 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,
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.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd June 30, 2015
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.Dt RANDOM_HARVEST 9
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.Os
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.Sh NAME
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.Nm random_harvest
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.Nd gather entropy from the kernel for the entropy device
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/random.h
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.Ft void
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.Fo random_harvest_direct
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.Fa "void *entropy"
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.Fa "u_int size"
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.Fa "u_int bits"
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.Fa "enum esource source"
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.Fc
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.Ft void
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.Fo random_harvest_fast
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.Fa "void *entropy"
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.Fa "u_int size"
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.Fa "u_int bits"
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.Fa "enum esource source"
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.Fc
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.Ft void
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.Fo random_harvest_queue
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.Fa "void *entropy"
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.Fa "u_int size"
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.Fa "u_int bits"
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.Fa "enum esource source"
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.Fc
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.Sh DESCRIPTION
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The
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.Fn random_harvest_*
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functions are used by device drivers
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and other kernel processes to pass data
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that is considered (at least partially) stochastic
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to the entropy device.
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.Pp
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The caller should pass
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a pointer pointing to the
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.Dq random
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data in
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.Fa entropy .
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The argument
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.Fa size
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contains the number of bytes pointed to.
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The
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.Fa source
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is chosen from one of
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the values enumerated in
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.Pa sys/dev/random.h .
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and is used to indicate the source of the entropy.
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.Pp
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The
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.Fo random_harvest_direct
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.Fc
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variant is used
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for early harvesting
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before any multitasking
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is enabled.
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.Pp
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The
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.Fn random_harvest_fast
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variant is used
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by sources that
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should not take
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a performance hit
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from harvesting,
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as they are high-rate
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sources.
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Some entropy is sacrificed,
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but the hig rate of supply
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will compensate for this.
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.Pp
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The
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.Fn random_harvest_queue
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variant is used
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for general harvesting
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and is the default
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choice for most entropy sources
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such as interrupts
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or console events.
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.Pp
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The
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.Fa bits
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argument is only used
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by the deprecated Yarrow algorithm.
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For compatibility,
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the caller should
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.Em "very conservatively"
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estimate the number of random bits
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in the sample,
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and pass this in
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.Fa bits .
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.Pp
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Interrupt harvesting has been
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in part simplified simplified
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for the kernel programmer.
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If a device driver registers an interrupt handler
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with
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.Xr BUS_SETUP_INTR 9
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or
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.Xr bus_setup_intr 9 ,
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then it is only necessary to
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include the
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.Dv INTR_ENTROPY
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bit in the
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.Fa flags
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argument to have that interrupt source
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be used for entropy harvesting.
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This should be done wherever practicable.
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.Sh SEE ALSO
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.Xr random 4 ,
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.Xr BUS_SETUP_INTR 9
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.Sh AUTHORS
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The
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.Fx
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.Xr random 4
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entropy device and supporting documentation was written by
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.An Mark R V Murray .
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