9f509a92e5
o Each source gets its own queue, which is a FIFO, not a ring buffer.
The FIFOs are implemented with the sys/queue.h macros. The separation
is so that a low entropy/high rate source can't swamp the harvester
with low-grade entropy and destroy the reseeds.
o Each FIFO is limited to 256 (set as a macro, so adjustable) events
queueable. Full FIFOs are ignored by the harvester. This is to
prevent memory wastage, and helps to keep the kernel thread CPU
usage within reasonable limits.
o There is no need to break up the event harvesting into ${burst}
sized chunks, so retire that feature.
o Break the device away from its roots with the memory device, and
allow it to get its major number automagically.
87 lines
3.2 KiB
C
87 lines
3.2 KiB
C
/*-
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* Copyright (c) 2001 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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/* This header contains only those definitions that are global
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* and non algorithm-specific for the entropy processor
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*/
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/* #define ENTROPYSOURCE nn entropy sources (actually classes)
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* This is properly defined in
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* an enum in sys/random.h
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*/
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/* Cryptographic block size in bits */
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#define BLOCKSIZE 256
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/* The ring size _MUST_ be a power of 2 */
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#define HARVEST_RING_SIZE 1024 /* harvest ring buffer size */
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#define HARVEST_RING_MASK (HARVEST_RING_SIZE - 1)
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#define HARVESTSIZE 16 /* max size of each harvested entropy unit */
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SYSCTL_DECL(_kern_random);
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MALLOC_DECLARE(M_ENTROPY);
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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 {
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uintmax_t somecounter; /* fast counter for clock jitter */
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u_char entropy[HARVESTSIZE]; /* the harvested entropy */
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u_int size, bits, frac; /* stats about the entropy */
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enum esource source; /* stats about the entropy */
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STAILQ_ENTRY(harvest) next; /* next item on the list */
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};
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void random_init(void);
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void random_deinit(void);
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void random_init_harvester(void (*)(u_int64_t, void *, u_int, u_int, u_int, enum esource), int (*)(void *, int));
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void random_deinit_harvester(void);
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void random_set_wakeup_exit(void *);
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void random_process_event(struct harvest *event);
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void random_reseed(void);
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void random_unblock(void);
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int read_random_real(void *, int);
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/* If this was c++, this would be a template */
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#define RANDOM_CHECK_UINT(name, min, max) \
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static int \
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random_check_uint_##name(SYSCTL_HANDLER_ARGS) \
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{ \
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if (oidp->oid_arg1 != NULL) { \
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if (*(u_int *)(oidp->oid_arg1) <= (min)) \
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*(u_int *)(oidp->oid_arg1) = (min); \
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else if (*(u_int *)(oidp->oid_arg1) > (max)) \
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*(u_int *)(oidp->oid_arg1) = (max); \
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} \
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return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, \
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req); \
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}
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