db9c8f48d9
Simplify RANDOM_LOADABLE by removing the ability to unload a LOADABLE random(4) implementation. This allows one-time random module selection at boot, by loader(8). Swapping modules on the fly doesn't seem especially useful. This removes the need to hold a lock over the sleepable module calls read_random and read_random_uio. init/deinit have been pulled out of random_algorithm entirely. Algorithms can run their own sysinits to initialize; deinit is removed entirely, as algorithms can not be unloaded. Algorithms should initialize at SI_SUB_RANDOM:SI_ORDER_SECOND. In LOADABLE systems, algorithms install a pointer to their local random_algorithm context in p_random_alg_context at that time. Go ahead and const'ify random_algorithm objects; there is no need to mutate them at runtime. LOADABLE kernel NULL checks are removed from random_harvestq by ordering random_harvestq initialization at SI_SUB_RANDOM:SI_ORDER_THIRD, after algorithm init. Prior to random_harvestq init, hc_harvest_mask is zero and no events are forwarded to algorithms; after random_harvestq init, the relevant pointers will already have been installed. Remove the bulk of random_infra shim wrappers and instead expose the bare function pointers in sys/random.h. In LOADABLE systems, read_random(9) et al are just thin shim macros around invoking the associated function pointer. We do not provide a registration system but instead expect LOADABLE modules to register themselves at SI_SUB_RANDOM:SI_ORDER_SECOND. An example is provided in randomdev.c, as used in the random_fortuna.ko module. Approved by: csprng(markm) Discussed with: gordon Differential Revision: https://reviews.freebsd.org/D22512
116 lines
3.6 KiB
C
116 lines
3.6 KiB
C
/*-
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* Copyright (c) 2000-2015 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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* 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_RANDOMDEV_H_INCLUDED
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#define SYS_DEV_RANDOM_RANDOMDEV_H_INCLUDED
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#ifdef _KERNEL
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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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#ifdef SYSCTL_DECL /* from sysctl.h */
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SYSCTL_DECL(_kern_random);
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SYSCTL_DECL(_kern_random_initial_seeding);
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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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#endif /* SYSCTL_DECL */
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MALLOC_DECLARE(M_ENTROPY);
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extern bool random_bypass_before_seeding;
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extern bool read_random_bypassed_before_seeding;
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extern bool arc4random_bypassed_before_seeding;
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extern bool random_bypass_disable_warnings;
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#endif /* _KERNEL */
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struct harvest_event;
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typedef void random_alg_pre_read_t(void);
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typedef void random_alg_read_t(uint8_t *, size_t);
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typedef bool random_alg_seeded_t(void);
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typedef void random_alg_eventprocessor_t(struct harvest_event *);
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typedef u_int random_source_read_t(void *, u_int);
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/*
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* Random Algorithm is a processor of randomness for the kernel
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* and for userland.
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*/
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struct random_algorithm {
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const char *ra_ident;
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u_int ra_poolcount;
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random_alg_pre_read_t *ra_pre_read;
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random_alg_read_t *ra_read;
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random_alg_seeded_t *ra_seeded;
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random_alg_eventprocessor_t *ra_event_processor;
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};
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#if defined(RANDOM_LOADABLE)
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extern const struct random_algorithm *p_random_alg_context;
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#else
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extern const struct random_algorithm random_alg_context;
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#define p_random_alg_context (&random_alg_context)
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#endif
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#ifdef _KERNEL
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/*
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* Random Source is a source of entropy that can provide
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* specified or approximate amount of entropy immediately
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* upon request.
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*/
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struct random_source {
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const char *rs_ident;
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enum random_entropy_source rs_source;
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random_source_read_t *rs_read;
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};
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void random_source_register(struct random_source *);
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void random_source_deregister(struct random_source *);
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#endif /* _KERNEL */
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void randomdev_unblock(void);
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#endif /* SYS_DEV_RANDOM_RANDOMDEV_H_INCLUDED */
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