This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [RESEND-2][PATCH][BZ 13761] Fix allocation in nss_compat forlarge number of memberships to a group
On Wed, Mar 28, 2012 at 3:41 PM, Siddhesh Poyarekar
<siddhesh.poyarekar@gmail.com> wrote:
> On Wed, Mar 28, 2012 at 3:29 PM, Andreas Jaeger <aj@suse.com> wrote:
>>> nss_compat allocates buffer space on stack using alloca (and
>>> extend_alloca) for initgroup and keeps extending it to fit in larger
>>> lines. This breaks for cases where the number of members in a gorup
>>> are very large, causing the alloca reference to go beyond thread stack
>>> boundary. Attached patch falls back to malloc/free if the buffer size
>>> needed is beyond __libc_alloca_cutoff.
>>
>>
>> Please state in your submission how and where this was tested.
>>
>> The patch itself looks fine to me but I'd like to hear about testing,
>
> I tested this using the reproducer steps described in the bug report
> as well as with an ldap group with large number of users. I've tried
> this on x86_64 boxes with backports of the patch to RHEL-5 (patch
> needed modifications), RHEL-6 and also on my F-16 box with glibc built
> off HEAD.
>
Updated ChangeLog with the bz number:
ChangeLog:
2012-02-09 Siddhesh Poyarekar <siddhesh@redhat.com>
[BZ #13761]
* nis/nss_compat/compat-initgroups.c (getgrent_next_nss,
_nss_compat_initgroups_dyn): Fall back to malloc/free for
large group memberships.
Regards,
Siddhesh
--
Siddhesh Poyarekar
http://siddhesh.in