glibc 2.24 -- Release blockers

[Florian Weimer]

On 07/15/2016 01:32 PM, Dmitry V. Levin wrote:
> On Fri, Jul 15, 2016 at 12:52:33PM +0200, Florian Weimer wrote:
>> On 07/15/2016 02:45 AM, Paul Eggert wrote:
>>> On 07/14/2016 01:27 PM, Florian Weimer wrote:
>>>> GDB does this to disable randomization:
>>>
>>> Thanks. Emacs disables ASLR by invoking the 'setfattr -n user.pax.flags
>>> -v er' shell command on the Emacs executable before running it ('paxctl
>>> +a' on older systems). Does this approach not work on ppc64? If not,
>>> what shell command would work?
>>
>> I have never seen these commands before.  On mainline Linux, you need to
>> use setarch (perhaps from a shell script wrapper), and this calls
>> personality internally.
>
> One has to use personality(personality(0xffffffff)|ADDR_NO_RANDOMIZE)
> approach as implemented in GDB, a simple shell script wrapper cannot
> implement this.

Would you please elaborate?

In my testing, the ADDR_NO_RANDOMIZE bit is inherited by subprocesses 
(which is a problem in itself, of course, because it disables hardening 
in network helpers used by Emacs).

Thanks,
Florian