script executables

[Stephen Smalley]

On Fri, 2007-01-26 at 10:25 -0800, Michael Thomas wrote:
> Stephen Smalley wrote:
> > On Fri, 2007-01-26 at 09:36 -0800, Michael Thomas wrote:
> >> I'm working on selinux protection for a python script daemon that is 
> >> started inside of an init.d script.  Inside the init.d script the python 
> >> daemon is invoked as:
> >>
> >> python myscript.py --daemon --pid=... --log=...
> >>
> >> I'd like to have this process run under its own domain.  The worst thing 
> >> I could do is to relabel python with that domain, but that would just be 
> >> really bad and sloppy, and not really an option.
> >>
> >> Another option that I've gotten to work is to use a wrapper shell script 
> >> to invoke the python commands.  The init.d script invokes the wrapper 
> >> script, which is labeled with the desired domain.
> >>
> >> But I was wondering of there was another way to get myscript.py to run 
> >> under a specific domain without using an application-specific wrapper. 
> >> Something like 'sedomainexec myappd_t python myscript.py --daemon ...'
> >> Is the wrapper script my only option?
> > 
> > If myscript.py starts with #!//usr/bin/python -E, then you can just
> > label the file with an appropriate _exec_t type and have it
> > automatically transition into its own domain.  SELinux supports domain
> > transitions on scripts (unlike setuid), although naturally you should
> > only do that when you trust the calling domain.
> > 
> > You can also use runcon -t to manually launch a program of any kind in a
> > particular domain.
> 
> runcon is exactly what I need.  Thanks!
> 
> Unfortunately...  It seems that runcon is greedy about parsing command 
> line options.  If I use any '--foo' arguments to my command, runcon 
> interprets them as its own arguments and usually throws an error:
> 
> # runcon system_u:object_r:httpd_exec_t ls --all

That's a file context, not a process context.

And you can disable option parsing via the usual trick, "--", e.g.
	runcon -t httpd_t -- ls --all

but that will fail on the entrypoint permission check.  So you are
better off doing:
	chcon -t httpd_exec_t myscript.py
and letting it do an automatic transition via direct execution, e.g.
	./myscript.py

> runcon: unrecognized option `--all'
> Usage: runcon CONTEXT COMMAND [args]
>    or:  runcon [ -c ] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] COMMAND 
> [args]
> Run a program in a different security context.
> 
>    CONTEXT            Complete security context
>    -c, --compute      compute process transition context before modifying
>    -t, --type=TYPE    type (for same role as parent)
>    -u, --user=USER    user identity
>    -r, --role=ROLE    role
>    -l, --range=RANGE  levelrange
>        --help         display this help and exit
>        --version      output version information and exit
> 
> 
> I'll file this in bugzilla.


-- 
Stephen Smalley
National Security Agency