[PATCH] nss_db: Fix initialization of iteration position [BZ #20237]

[Carlos O'Donell]

On 06/10/2016 11:55 AM, Florian Weimer wrote:
> On 06/10/2016 05:44 PM, Carlos O'Donell wrote:
>> On 06/10/2016 04:54 AM, Florian Weimer wrote:
>>> When get*ent is called without a preceding set*ent, we need
>>> to set the initial iteration position in get*ent.
>>>
>>> Reproducer: Add “services: db files” to /etc/nsswitch.conf, then run
>>> “perl -e getservent”.  It will segfault before this change, and exit
>>> silently after it.
>>>
>>> 2016-06-10  Florian Weimer  <fweimer@redhat.com>
>>>
>>>     [BZ #20237]
>>>     * nss/nss_db/db-XXX.c (set*ent): Reset entidx to NULL.
>>>     (get*ent): Set entidx to NULL during initialization.  If entidx is
>>>     NULL, start iteration from the beginning.
>>
>> The fix looks good, but surely this needs a regression test?
> 
> The problems are quite similar to nss_files testing:
> 
>   https://sourceware.org/ml/libc-alpha/2016-04/msg00392.html
> 
> Build-time testing is only possible with chroot and (user) namespaces.

I have now reviewed nss_files. I think you should be moving forward
with checking that in, the code is elegant and allows for easy to write
compositional tests that run in a chroot or namespace.


-- 
Cheers,
Carlos.