Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 20 Feb 2015 06:30:41 +0000
From: Tim Brown <>
Cc: Paul Pluzhnikov <>
Subject: Re: Fixing the glibc runtime linker

On Friday 20 February 2015 01:38:31 Paul Pluzhnikov wrote:
> On Thu, Feb 19, 2015 at 2:19 PM, Tim Brown <> wrote:
> > More often than not, the underlying issue is an empty element within the
> > DT_RPATH header or equivalent. Sometimes it's not, but even in those
> > cases, it is largely that one or more elements isn't qualifed (i.e. it
> > doesn't start with /). The attached patch fixes this, by ignoring any
> > elements of DT_RPATH, LD_LIBRARY_PATH that do not start with a /, and/or
> > junking any use of dlopen where the filename is likewise unqualified.
> > 
> > Won't this break stuff?
> FWIW, relative RPATHs are quite fundamental to our test execution
> environment, and any patch that unconditionally ignores them would
> have to be reverted in our tree.

That's useful to know. Is that for setuid binaries or more generally? As I 
noted, it would be dead easy only to use the part of the patch that rejects 
them for the former only. Although as I said, that offers less protection. 
Would that make the patch more consumable? Another option would be to have 
something like /etc/suid-debug which could flag that an override is in 

> Also, don't you want to discuss this on libc-alpha? oss-security could
> be all for it, but without buy-in from libc-alpha your patch is
> unlikely to be going anywhere.

I'm intending to, but getting security folk, who may well wear slightly more 
positive hats to begin with, to review it, seemed like a safe place to start. 
I can well imagine pursuading the glibc folk will be more difficult :/.

Tim Brown

Download attachment "signature.asc " of type "application/pgp-signature" (820 bytes)

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.