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| -rw-r--r-- | share/man/man7/Makefile | 2 | ||||
| -rw-r--r-- | share/man/man7/securelevel.7 | 121 |
2 files changed, 122 insertions, 1 deletions
diff --git a/share/man/man7/Makefile b/share/man/man7/Makefile index 35c7fd573b3..cbd5d0917d1 100644 --- a/share/man/man7/Makefile +++ b/share/man/man7/Makefile @@ -4,7 +4,7 @@ # missing: eqnchar.7 man.7 ms.7 term.7 MAN= ascii.7 environ.7 hier.7 hostname.7 intro.7 mailaddr.7 \ - mdoc.7 mdoc.samples.7 operator.7 ports.7 + mdoc.7 mdoc.samples.7 operator.7 ports.7 securelevel.7 MLINKS= mdoc.7 mandoc.7 mdoc.samples.7 mandoc.samples.7 .include <bsd.prog.mk> diff --git a/share/man/man7/securelevel.7 b/share/man/man7/securelevel.7 new file mode 100644 index 00000000000..7b1f1fbcc5a --- /dev/null +++ b/share/man/man7/securelevel.7 @@ -0,0 +1,121 @@ +.\" $OpenBSD: securelevel.7,v 1.1 2000/01/08 01:55:33 hugh Exp $ +.\" +.\" Copyright (c) 2000 Hugh Graham +.\" +.\" 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. +.\" +.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED +.\" WARRANTIES, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR 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. +.\" +.Dd January 4, 2000 +.Dt SECURELEVEL 7 +.Os +.Sh NAME +.Nm securelevel +.Nd securelevel and its effects +.Sh SYNOPSIS +The +.Ox +kernel provides four levels of system security: +.Bl -tag -width flag +.It -1 Em "Permanently insecure mode" . +.Xr init 8 +will not attempt to raise the securelevel. May be set via +.Xr sysctl 8 +while the system is insecure, or by building a kernel with +.Dq option INSECURE +in the config file. +.It 0 Em "Insecure mode" . +Used during bootstrapping and while the system is single user. +System file flags may be cleared, and all devices may be read or +written subject to their permissions. +.It 1 Em "Secure mode" . +Default mode when system is multiuser: +.Bl -hyphen -compact +.It +securelevel may no longer be lowered except by init +.It +system immutable and append-only file flags may not be removed +.It +.Pa /dev/mem +and +.Pa /dev/kmem +may not be written to +.It +kernel modules may not be loaded or unloaded +.El +.It 2 Em "Highly secure mode" . +All effects of securelevel 1, plus: +.Bl -hyphen -compact +.It +disk devices are always read-only whether mounted or not +.It +.Xr settimeofday 2 +may not set the time backwards +.It +.Xr ipf 8 +and +.Xr ipnat 8 +rulesets may not be changed +.El +.El +.Sh DESCRIPTION +Securelevel provides controlled means of +.Dq locking down +a system to a degree suited to its environment. It is normally set at +boot via the +.Xr rc.securelevel 8 +script, or the superuser may raise securelevel at any time by modifying the +.Va kern.securelevel +.Xr sysctl 8 +variable. However, only +.Xr init 8 +may lower it once the system has entered secure mode. +.Pp +.Em Highly secure mode +may seem Draconian, but is intended as a last line of defence should the +superuser account be compromised. Its effects preclude circumvention of +file flags by direct modification of a raw disk device, or erasure of a +filesystem by means of +.Xr newfs 8 . +Further, it can limit the potential damage of a compromised +.Dq firewall +by prohibiting the modification of packet filter rules. Preventing +the system clock from being set backwards aids in post-mortem analysis +and helps ensure the intergrity of logs. Precision timekeeping is not +affected because the clock may still be slowed. +.Sh FILES +.Bl -tag -compact +.It Pa /etc/rc.securelevel +.El +.Sh SEE ALSO +.Xr init 8 , +.Xr rc 8 , +.Xr sysctl 8 , +.Xr chflags 2 , +.Xr settimeofday 2 , +.Xr options 4 +.Sh BUGS +The list of securelevel's effects may not be comprehensive. +.Sh HISTORY +The +.Nm +manual page first appeared in +.Ox 2.6 . + |