freebsd-dev/sys/dev/random/random_infra.c
Pawel Biernacki 4312ebfe0b Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (18 of many)
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE.  All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Reviewed by:	cem
Approved by:	csprng, kib (mentor, blanket)
Differential Revision:	https://reviews.freebsd.org/D23841
2020-02-27 13:12:14 +00:00

106 lines
4.5 KiB
C

/*-
* Copyright (c) 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.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/random.h>
#include <sys/sysctl.h>
#include <dev/random/randomdev.h>
/* Set up the sysctl root node for the entropy device */
SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"Cryptographically Secure Random Number Generator");
SYSCTL_NODE(_kern_random, OID_AUTO, initial_seeding,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"Initial seeding control and information");
/*
* N.B., this is a dangerous default, but it matches the behavior prior to
* r346250 (and, say, OpenBSD -- although they get some guaranteed saved
* entropy from the prior boot because of their KARL system, on RW media).
*/
bool random_bypass_before_seeding = true;
SYSCTL_BOOL(_kern_random_initial_seeding, OID_AUTO,
bypass_before_seeding, CTLFLAG_RDTUN, &random_bypass_before_seeding,
0, "If set non-zero, bypass the random device in requests for random "
"data when the random device is not yet seeded. This is considered "
"dangerous. Ordinarily, the random device will block requests until "
"it is seeded by sufficient entropy.");
/*
* This is a read-only diagnostic that reports the combination of the former
* tunable and actual bypass. It is intended for programmatic inspection by
* userspace administrative utilities after boot.
*/
bool read_random_bypassed_before_seeding = false;
SYSCTL_BOOL(_kern_random_initial_seeding, OID_AUTO,
read_random_bypassed_before_seeding, CTLFLAG_RD,
&read_random_bypassed_before_seeding, 0, "If non-zero, the random device "
"was bypassed because the 'bypass_before_seeding' knob was enabled and a "
"request was submitted prior to initial seeding.");
/*
* This is a read-only diagnostic that reports the combination of the former
* tunable and actual bypass for arc4random initial seeding. It is intended
* for programmatic inspection by userspace administrative utilities after
* boot.
*/
bool arc4random_bypassed_before_seeding = false;
SYSCTL_BOOL(_kern_random_initial_seeding, OID_AUTO,
arc4random_bypassed_before_seeding, CTLFLAG_RD,
&arc4random_bypassed_before_seeding, 0, "If non-zero, the random device "
"was bypassed when initially seeding the kernel arc4random(9), because "
"the 'bypass_before_seeding' knob was enabled and a request was submitted "
"prior to initial seeding.");
/*
* This knob is for users who do not want additional warnings in their logs
* because they intend to handle bypass by inspecting the status of the
* diagnostic sysctls.
*/
bool random_bypass_disable_warnings = false;
SYSCTL_BOOL(_kern_random_initial_seeding, OID_AUTO,
disable_bypass_warnings, CTLFLAG_RDTUN,
&random_bypass_disable_warnings, 0, "If non-zero, do not log a warning "
"if the 'bypass_before_seeding' knob is enabled and a request is "
"submitted prior to initial seeding.");
MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers and data structures");
#if defined(RANDOM_LOADABLE)
const struct random_algorithm *p_random_alg_context;
void (*_read_random)(void *, u_int);
int (*_read_random_uio)(struct uio *, bool);
bool (*_is_random_seeded)(void);
#endif /* defined(RANDOM_LOADABLE) */