Apache 403错误&SELinux解决方案

初次搭建Apache服务器，在/var/www/html目录下测试正常，然后在普通用户的/home/目录下建立public_html存放html文件，用浏览器访问时出现403 Forbidden 错误。

这个问题与SELinux有关，SELinux是一种安全策略机制，它限制了进程只能访问跟它自己有关的文件或目录（大意），即便文件或目录的权限设置都正常，SELinux的安全策略还是会继续检查是否可以访问，因此，由于普通用户建立的html主页其文件策略类型是user_home_t，而Apache的进程所使用的SELinux安全策略要求只能访问httpd_sys_content_t策略类型的文件/目录，所以造成了403错误。

解决办法：

＃chcon -R -t httpd_sys_content_t /home/普通用户名/public_html/

然后可以用ls -laZ来查看文件/目录的策略类型，之后在这个目录中生成的文件，其安全策略类型会自动设为httpd_sys_content_t。

原文链接：

Apache
(httpd) 403 errors & SELinux in FC3
Posted by jwigdahl @ 17 Nov 2004 10:38 am

Quick fix:

chcon -R -t httpd_sys_content_t <path to web files>

Now for the meat:

So in Fedora Core 3 we now have SELinux enabled by default in the installation. I decided to leave it enabled because security is a "Good Thing" (right?) and I knew I was going to have to get familiar with it at some point. So this was all fine and good until
I ran into the first piece of the system I wanted to work with that was affected by the default policy that's called "targeted".

The "targeted" policy confines certain network daemons to run in their own specific "security domain". These daemons include dhcpd, httpd (apache), named, nscd, ntpd, portmap, snmpd, squid, and syslogd.

When I setup apache on a system where it wil be utilized, I have a habit of not using /var/www/html as my starting point for document roots, but rather create a dir at /home/websites and place my document roots in there. In the good ol' days of Discretionary
Access Controls (DAC) just making sure that apache had the perms it needed to read the documents in there was enough (using chmod, chown, and the like).

Not so with SELinux enabled. In addition to the regular DAC we're all used to, we now have Mandatory Access Controls (MAC) that define security contexts for files/directories etc. Turns out it looks like by default, apache only has access to /var/www/html when
it's fired up.... I'm guessing that and probably /var/log/httpd (which is exactly as it should be). To enable apache to view my files in /home/websites, I had to apply a new security context to these files. The answer to this is the chcon command.
To be brief, the full command I executed was:

chcon -R -t httpd_sys_content_t /home/websites

After executing this, apache could read my files.

Important links I found in troubleshooting:

http://fedora.redhat.com/docs/selinux-apache-fc3

http://fedora.redhat.com/docs/selinux-faq-fc3/

http://lwn.net/Articles/105409/

I like where this SELinux thing is going. Permissions done right, for sure. This doesn't come with out growing pains though. It's complex (or so it seems to me after only working with it for a couple days) and will take some time to learn. I'm prepared for
some frustration....

Now many of you are probably asking yourself why would anyone (let alone me) want to bother with this? Well I think a simple example of one
4000
of the cool things is that even though something like /etc/passwd has DAC octal perms of 644 (rw-r--r--), apache still
can't read it because that file is not with in apache's security context. So any users on your system can't write a little script that reads your /etc/passwd file and basically posts it on a web page for the world to see (giving potential crackers a list of
valid user accounts on the system).

UPDATE: Thanks for the updated link Bob.