Re: Is PIE randomization breaking klibc binaries?

Jiri Kosina
2007-08-02T21:03:20Z

On Thu, 2 Aug 2007, H. Peter Anvin wrote:

> Yup... it should probably be pointed out the reason the old kernel
> worked was nothing but pure dumb luck. This was a GNU ld change which
> needed to be undone for klibc. It's unfortunate that stock x86-64
> binaries leave as little of a null pointer range as they do, but that's
> life, unfortunately. The other alternative is to map klibc just below
> the 2 GB point, which would also work, but the old way broke when the ld
> change went in. As previously stated, klibc-1.4.35 or higher fixes
> this.

Thanks for pointing this out. So it seems that maybe the mainline revert
of pie-randomization.patch was a little bit premature. Bret -- could you
please clarify whether you have experienced also klibc-related segfaults
with pie-randomization.patch applied, or you have had just random binaries
segfaulting, as you pointed out here: http://lkml.org/lkml/2007/7/21/31

Seems like you are also using ubuntu, same as Ulrich, so you might have
been hitting the very same behavior of klibc-1.4.

Thanks in advance for clarifying this, so that I can eventually resubmit
the pie-randomization patch.

Thanks,

--
Jiri Kosina
SUSE Labs