freebsd-skq/sys/dev/random/randomdev.h
Conrad Meyer 3ee1d5bb9d random(4): Simplify RANDOM_LOADABLE
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
2019-12-26 19:32:11 +00:00

116 lines
3.6 KiB
C

/*-
* Copyright (c) 2000-2015 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef SYS_DEV_RANDOM_RANDOMDEV_H_INCLUDED
#define SYS_DEV_RANDOM_RANDOMDEV_H_INCLUDED
#ifdef _KERNEL
/* This header contains only those definitions that are global
* and non algorithm-specific for the entropy processor
*/
#ifdef SYSCTL_DECL /* from sysctl.h */
SYSCTL_DECL(_kern_random);
SYSCTL_DECL(_kern_random_initial_seeding);
#define RANDOM_CHECK_UINT(name, min, max) \
static int \
random_check_uint_##name(SYSCTL_HANDLER_ARGS) \
{ \
if (oidp->oid_arg1 != NULL) { \
if (*(u_int *)(oidp->oid_arg1) <= (min)) \
*(u_int *)(oidp->oid_arg1) = (min); \
else if (*(u_int *)(oidp->oid_arg1) > (max)) \
*(u_int *)(oidp->oid_arg1) = (max); \
} \
return (sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, \
req)); \
}
#endif /* SYSCTL_DECL */
MALLOC_DECLARE(M_ENTROPY);
extern bool random_bypass_before_seeding;
extern bool read_random_bypassed_before_seeding;
extern bool arc4random_bypassed_before_seeding;
extern bool random_bypass_disable_warnings;
#endif /* _KERNEL */
struct harvest_event;
typedef void random_alg_pre_read_t(void);
typedef void random_alg_read_t(uint8_t *, size_t);
typedef bool random_alg_seeded_t(void);
typedef void random_alg_eventprocessor_t(struct harvest_event *);
typedef u_int random_source_read_t(void *, u_int);
/*
* Random Algorithm is a processor of randomness for the kernel
* and for userland.
*/
struct random_algorithm {
const char *ra_ident;
u_int ra_poolcount;
random_alg_pre_read_t *ra_pre_read;
random_alg_read_t *ra_read;
random_alg_seeded_t *ra_seeded;
random_alg_eventprocessor_t *ra_event_processor;
};
#if defined(RANDOM_LOADABLE)
extern const struct random_algorithm *p_random_alg_context;
#else
extern const struct random_algorithm random_alg_context;
#define p_random_alg_context (&random_alg_context)
#endif
#ifdef _KERNEL
/*
* Random Source is a source of entropy that can provide
* specified or approximate amount of entropy immediately
* upon request.
*/
struct random_source {
const char *rs_ident;
enum random_entropy_source rs_source;
random_source_read_t *rs_read;
};
void random_source_register(struct random_source *);
void random_source_deregister(struct random_source *);
#endif /* _KERNEL */
void randomdev_unblock(void);
#endif /* SYS_DEV_RANDOM_RANDOMDEV_H_INCLUDED */