2b72262b4f
I hereby relicense all my work on Sortix under the ISC license as below. All Sortix contributions by other people are already under this license, are not substantial enough to be copyrightable, or have been removed. All imported code from other projects is compatible with this license. All GPL licensed code from other projects had previously been removed. Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors. Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
/*
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* Copyright (c) 2014, 2015 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* random.cpp
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* Kernel entropy gathering.
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sortix/clock.h>
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#include <sortix/kernel/copy.h>
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#include <sortix/kernel/interlock.h>
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#include <sortix/kernel/syscall.h>
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#include <sortix/kernel/time.h>
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namespace Sortix {
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namespace Random {
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static unsigned long sequence = 0;
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bool HasEntropy()
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{
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// We only have new entropy once and that's at boot.
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return sequence == 0;
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}
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void GetEntropy(void* result, size_t size)
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{
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union
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{
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unsigned char buffer[256];
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struct
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{
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struct timespec realtime;
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struct timespec monotonic;
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unsigned long sequence;
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} seed;
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};
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if ( sizeof(buffer) < size )
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size = sizeof(buffer);
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// TODO: SECURITY: We need to actually gather entropy and deliver it.
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for ( size_t i = 0; i < size; i++ )
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buffer[i] = i;
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// NOTE: This is not random and is not meant to be random, this is just
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// meant to make the returned entropy a little different each time
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// until we have real randomness, even across reboots. The userland
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// arc4random mixer will mix it around and the produced streams will
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// look random and should not repeat in practice.
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seed.realtime = Time::Get(CLOCK_REALTIME);
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seed.monotonic = Time::Get(CLOCK_MONOTONIC);
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seed.sequence = InterlockedIncrement(&sequence).o;
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memcpy(result, buffer, size);
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}
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} // namespace Random
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} // namespace Sortix
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namespace Sortix {
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int sys_getentropy(void* user_buffer, size_t size)
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{
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unsigned char buffer[256];
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if ( sizeof(buffer) < size )
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return errno = EIO, -1;
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arc4random_buf(buffer, sizeof(buffer));
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if ( !CopyToUser(user_buffer, buffer, size) )
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return -1;
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return 0;
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}
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} // namespace Sortix
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