glibc 2.24 -- Release blockers

[Florian Weimer]

On 07/15/2016 04:28 PM, Sinny Kumari wrote:
> On Fri, Jul 15, 2016 at 7:49 PM, Sinny Kumari <ksinny@gmail.com> wrote:
>> On Fri, Jul 15, 2016 at 6:42 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
>>> On 07/15/2016 12:52 PM, Florian Weimer wrote:
>>>>
>>>> The problem is that this happens at dump time only, while the issue occurs
>>>> when running the dumped Emacs. Furthermore, the personality system call (or
>>>> at least ADDR_NO_RANDOMIZE) only applies to new process images, it does not
>>>> affected the randomization decisions made at load time for the current
>>>> process.
>>>
>>>
>>> I wrote a revised patch to emacs-25 (attached) which I hope addresses the
>>> former issue, by disabling randomization in both the undumped and dumped
>>> Emacs when Emacs uses its own allocator. Emacs already addresses the latter
>>> issue by re-execing itself when it changes personalities, so this shouldn't
>>> be an issue.
>>
>> After applying this patch in emacs-25.0.95, it builds and run fine on ppc64(le),
>> Fedora rawhide. It no longer consumes memory in GB !
>> For reference, scratch build link is
>> http://ppc.koji.fedoraproject.org/koji/taskinfo?taskID=3538651
>
> Also, output of "cat /proc/self/personality" inside emacs shell
> contains value 00040000

Thanks!

This means that new processes spawned by Emacs will have ASLR disable.

Paul, I think the patch should call personality again after it is active 
for the Emacs process, to disable it for subprocesses.

Florian