Selinux Apache avc denied

[Colin Walters]

On Fri, 2005-07-29 at 23:56 -0400, Valdis.Kletnieks at vt.edu wrote:
> On Fri, 29 Jul 2005 23:32:01 EDT, Alain Reguera Delgado said:
> 
> > I've been stopped the web development. I feel selinux is a brilliant
> > technology I'd like to implement in my webserver.
> 
> Actually, you have that almost totally backwards - SELinux is a brilliant
> technology that gets implemented in the kernel 

One of the good things about SELinux actually is that it covers more
than the kernel; e.g. dbus acts as a "userspace object manager" in
concert with the kernel to secure the whole system.  Similarly, there
are patches for Xorg.  I think it does make sense in some situations to
patch the webserver.

> Unfortunately, this is *much* too big a can of worms to solve directly - it
> would be technically possible to just add a rule that says 'httpd_t can
> exec shell_exec_t' - but that would be a *really* *bad* idea because then
> any exploit could get a shell (and exec_no_trans only partially minimizes
> the problem).

I don't see a problem with execute_no_trans; it stays within the httpd_t
security domain.  

> Policy Gurus:  How big a hole would adding a 'can_exec(sendmail_exec_t)' or
> 'domain_auto_trans(sendmail_t)' cause?  And how many of these common "web interface
> wants to send mail" problems would it solve?

I think policy already has this as httpd_t has the privmail attribute,
and policy grants:

./macros/program/mta_macros.te:63:domain_auto_trans(privmail, sendmail_exec_t, system_mail_t)

My guess is all we need for this problem is:
can_exec(httpd_t, shell_exec_t)