[PATCH] Ignore LD_POINTER_GUARD for set-user-ID/set-group-ID binaries.

[Hector Marco-Gisbert]

Hello all,

It would be nice if our names (Hector Marco and Ismael Ripoll) appear in the 
Changelog. At least showing that we reported the security issue.

Previously reported security issues (i.e BZ #15754) were properly credited in 
the Glibc Changelog.

Regarding security issues, the complexity relies on finding the issue rather 
than fixing it, which typically consists on adding or removing a few lines of code.

Developers that want contribute maybe discourage if their work is not recognized.


-- Hector Marco.


El 10/10/15 a las 03:59, Carlos O'Donell escribió:
> On 10/08/2015 04:44 AM, Florian Weimer wrote:
>> On 09/05/2015 06:39 PM, Hector Marco-Gisbert wrote:
>>> A weakness in the dynamic loader have been found, Glibc prior to
>>> 2.22.90 are affected. The issue is that the LD_POINTER_GUARD in the
>>> environment is not sanitized allowing local attackers easily to bypass
>>> the pointer guarding protection on set-user-ID and set-group-ID
>>> programs.
>>>
>>> Details of the weakness:
>>> http://hmarco.org/bugs/glibc_ptr_mangle_weakness.html
>>>
>>> This patch prevents to disable the pointer guarding protection for
>>> set-user-ID/set-group-ID programs.
>>>
>>> For example, executing "LD_POINTER_GUARD=0 /bin/ping" does not disable
>>> the pointer guarding protection unless it is directly executed by root
>>> (rUID==eUID).
>>
>> Does anyone actually use LD_POINTER_GUARD for debugging?  Maybe we can
>> simply retire the environment variable instead.
>
> I vote we remove it. It has long since passed the point of usefullness.
> With a proper tunables infrastructure we would have added it in one release
> while we tested things, and then removed it one or two releases later.
>
> Cheers,
> Carlos.
>

-- 
Hector Marco-Gisbert @ http://hmarco.org/
Cyber Security Researcher @ http://cybersecurity.upv.es
Universitat Politècnica de València (Spain)