RFC: Remove write permissions from executables

[Richard W.M. Jones]

On Fri, Jan 22, 2010 at 12:19:49PM +0100, Miloslav Trmač wrote:
> Hello,
> In Fedora 12 several daemons (e.g. dhclient) were modified to drop
> unnecessary capabilities, most importantly the "dac_override"
> capability, allowing the daemon to ignore file permission bits.  This,
> in combination with removing some permissions from important system
> directories and files (such as /etc/shadow), has restricted the amount
> of damage that can be done by exploiting such daemons.
> 
> We can extend the protection to all executables by a simple addition to
> redhat-rpm-config (https://bugzilla.redhat.com/show_bug.cgi?id=556897 ).
> After applying this patch, executable files in all rebuilt packages
> would not be writeable, most often using mode 0555.

Is it possible we could remove unreadable binaries with the same
change?  See:

http://www.redhat.com/archives/rhl-devel-list/2009-October/thread.html#00987

Rich.

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