freebsd-skq/sys/kern/subr_param.c
silby e3a68020c7 Unconditionally limit maxproc so that it is not possible
to exhaust all kmaps.  The only reward for setting maxproc
to a value which will cause kmap exhaustion is a panic
during a forkbomb attack.

MFC after:	3 days
2002-03-07 04:50:36 +00:00

172 lines
5.3 KiB
C

/*
* Copyright (c) 1980, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*
* @(#)param.c 8.3 (Berkeley) 8/20/94
* $FreeBSD$
*/
#include "opt_param.h"
#include "opt_maxusers.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <machine/vmparam.h>
/*
* System parameter formulae.
*/
#ifndef HZ
#define HZ 100
#endif
#define NPROC (20 + 16 * maxusers)
#ifndef NBUF
#define NBUF 0
#endif
#ifndef MAXFILES
#define MAXFILES (maxproc * 2)
#endif
int hz;
int tick;
int tickadj; /* can adjust 30ms in 60s */
int maxusers; /* base tunable */
int maxproc; /* maximum # of processes */
int maxprocperuid; /* max # of procs per user */
int maxfiles; /* sys. wide open files limit */
int maxfilesperproc; /* per-proc open files limit */
int ncallout; /* maximum # of timer events */
int nbuf;
int nswbuf;
int maxswzone; /* max swmeta KVA storage */
int maxbcache; /* max buffer cache KVA storage */
u_quad_t maxtsiz; /* max text size */
u_quad_t dfldsiz; /* initial data size limit */
u_quad_t maxdsiz; /* max data size */
u_quad_t dflssiz; /* initial stack size limit */
u_quad_t maxssiz; /* max stack size */
u_quad_t sgrowsiz; /* amount to grow stack */
/*
* These have to be allocated somewhere; allocating
* them here forces loader errors if this file is omitted
* (if they've been externed everywhere else; hah!).
*/
struct buf *swbuf;
/*
* Boot time overrides that are not scaled against main memory
*/
void
init_param1(void)
{
hz = HZ;
TUNABLE_INT_FETCH("kern.hz", &hz);
tick = 1000000 / hz;
tickadj = howmany(30000, 60 * hz); /* can adjust 30ms in 60s */
#ifdef VM_SWZONE_SIZE_MAX
maxswzone = VM_SWZONE_SIZE_MAX;
#endif
TUNABLE_INT_FETCH("kern.maxswzone", &maxswzone);
#ifdef VM_BCACHE_SIZE_MAX
maxbcache = VM_BCACHE_SIZE_MAX;
#endif
TUNABLE_INT_FETCH("kern.maxbcache", &maxbcache);
maxtsiz = MAXTSIZ;
TUNABLE_QUAD_FETCH("kern.maxtsiz", &maxtsiz);
dfldsiz = DFLDSIZ;
TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz);
maxdsiz = MAXDSIZ;
TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz);
dflssiz = DFLSSIZ;
TUNABLE_QUAD_FETCH("kern.dflssiz", &dflssiz);
maxssiz = MAXSSIZ;
TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz);
sgrowsiz = SGROWSIZ;
TUNABLE_QUAD_FETCH("kern.sgrowsiz", &sgrowsiz);
}
/*
* Boot time overrides that are scaled against main memory
*/
void
init_param2(int physpages)
{
/* Base parameters */
maxusers = MAXUSERS;
TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
if (maxusers == 0) {
maxusers = physpages / (2 * 1024 * 1024 / PAGE_SIZE);
if (maxusers < 32)
maxusers = 32;
if (maxusers > 384)
maxusers = 384;
}
/*
* The following can be overridden after boot via sysctl. Note:
* unless overriden, these macros are ultimately based on maxusers.
*/
maxproc = NPROC;
TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
/*
* Limit maxproc so that kmap entries cannot be exhausted by
* processes.
*/
if (maxproc > (physpages / 12))
maxproc = physpages / 12;
maxfiles = MAXFILES;
TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
maxprocperuid = (maxproc * 9) / 10;
maxfilesperproc = (maxfiles * 9) / 10;
/*
* Cannot be changed after boot.
*/
nbuf = NBUF;
TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
ncallout = 16 + maxproc + maxfiles;
TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
}