How to disable SELinux
http://www.haw-haw.org/node/30：这个文章主要是说怎样disable掉SELinux
http://www.crypt.gen.nz/selinux/disable_selinux.html：这个文章比较细的说明了相关问题。
我把两个都copy到这里来
文章一：
selinux是个新东东
在linux kernel 2.6的系统（如as4、fc3）里常见
一般如果在2.6的kernel的机器上出什么莫名其妙的权限的错误
大家都可以想想是不是selinux的策略问题
以我现在的想法
最好是已开始就把selinux disable掉！
方法是编辑文件/etc/sysconfig/selinux
把SELINUX设为disabled
像这样：
SELINUX=disabled
在重起机器selinux就被忽略了
命令setenforce 0可以直接干掉selinux 直接生效
不用重启机器
文章二：
You've setup a new system, or installed something new on your
Linux system and its not working. You get the feeling that SELinux
is the cause of the problem. This page was written to help.
Contents
Overview
SELinux has two major components on your system. There's the kernel
mechanism which is enforcing a bunch of access rules which apply to
processes and files. And secondly, there's file labels : every file
on your system has extra labels attached to it which tie-in with
those access rules. Run ls -Z and you'll see what I mean.
Should you really disable SELinux?
Be aware that by disabling SELinux you will be removing a security
mechanism on your system. Think about this carefully, and if your
system is on the Internet and accessed by the public, then think
about it some more. Joshua Brindle (an SELinux developer) has
comments on disabling SELinux here, which states clearly that
applications should be fixed to work with SELinux, rather than
disabling the OS security mechanism.
You need to decide if you want to disable SELinux temporarily to
test the problem, or permanently switch it off. It may also be a
better option to make changes to the policy to permit the
operations that are being blocked - but this requires knowledge of
writing policies and may be a steep learning curve for some people.
For the operating system as a whole, there is two kinds of
disabling:
•Permissive - switch the SELinux kernel into a mode where every
operation is allowed. Operations that would be denied are allowed
and a message is logged identifying that it would be denied. The
mechanism that defines labels for files which are being
created/changed is still active.
•Disabled - SELinux is completely switched off in the kernel. This
allows all operations to be permitted, and also disables the
process which decides what to label files &
processes with.
Disabling SELinux could lead to problems if you want to re-enable
it again later. When the system runs with file labelling disable it
will create files with no label - which could cause problems if the
system is booted into Enforcement mode. A full re-labelling of the
file system will be necessary.
Temporarily switch off enforcement
You can switch the system into permissive mode with the following
command:
echo 0 >/selinux/enforceYou'll need to be logged in
as root, and in the sysadm_r role:
newrole -r sysadm_rTo switch back into enforcing mode:
echo 1 >/selinux/enforceIn Fedora Core and RedHat
Enterprise Linux you can use the setenforce command with a 0 or 1
option to set permissive or enforcing mode, its just a slightly
easier command than the above.
To check what mode the system is in,
cat /selinux/enforcewhich will print a "0" or "1" for permissive or enforcing - probably printed at the beginning of the line of the command prompt.
Permanently Permissive
The above will switch off enforcement temporarily - until you
reboot the system. If you want the system to always start in
permissive mode, then here is how you do it.
In Fedora Core and RedHat Enterprise, edit /etc/selinux/config and
you will see some lines like this:
# This file controls the state of SELinux on the system.#
SELINUX= can take one of these three values:# enforcing - SELinux
security policy is enforced.# permissive - SELinux prints warnings
instead of enforcing.# disabled - No SELinux policy is
loaded.SELINUX=enforcing# SELINUXTYPE= can take one of these two
values:# targeted - Only targeted network daemons are protected.#
strict - Full SELinux protection.SELINUXTYPE=targeted... just
change SELINUX=enforcing to SELINUX=permissive, and you're done.
Reboot if you want to prove it.
For the other Linuxes which don't have the /etc/selinux/config
file, you just need to edit the kernel boot line, usually in
/boot/grub/grub.conf if you're using the GRUB boot loader. On the
kernel line, add enforcing=0 at the end. For example,
title SE-Linux Test System
Fully Disabling SELinux
Fully disabling SELinux goes one step further than just switching
into permissive mode. Disabling will completely disable all SELinux
functions including file and process labelling.
In Fedora Core and RedHat Enterprise, edit /etc/selinux/config and
change the SELINUX line to SELINUX=disabled:
# This file controls the state of SELinux on the system.#
SELINUX= can take one of these three values:# enforcing - SELinux
security policy is enforced.# permissive - SELinux prints warnings
instead of enforcing.# disabled - No SELinux policy is
loaded.SELINUX=disabled# SELINUXTYPE= can take one of these two
values:# targeted - Only targeted network daemons are protected.#
strict - Full SELinux protection.SELINUXTYPE=targeted... and then
reboot the system.
For the other Linuxes which don't have the /etc/selinux/config
file, you just need to edit the kernel boot line, usually in
/boot/grub/grub.conf, if you're using the GRUB boot loader. On the
kernel line, add selinux=0 at the end. For example,
title SE-Linux Test
System
Re-Enabling SELinux
If you've disabled SELinux as in the section above, and you want to
enable it again then you've got a bit of work to do. The problem
will be that files created or changed when SELinux was disabled
won't have the correct file labels on them - if you just reboot in
enforcing mode then a lot of stuff won't work properly.
What you need to do is to enable SELinux by editing
/etc/selinux/config (for Fedora/RedHat) or by adding selinux=1 to
the kernel boot line, then boot into permissive mode, then relabel
everything, and then reboot into (or simply switch to) enforcing
mode.
After booting into permissive mode, run fixfiles relabel
Alternatively, in Fedora and RedHat Enterprise Linux you can run touch /.autorelabel and reboot or put autorelabel on the boot command line - in both cases the file system gets a full relabel early in the boot process. Note that this can take quite some time for systems with a large number of files.
After relabelling the filesystem, you can switch to enforcing
mode (see above) and your system should be fully enforcing
again.
