NIS+ groups, segfaults

[Dirk Wetter]

Hi all,

below you find a mail posted in November 2000 to the NIS+
Linux mailing list. Looks also for us like there's a
problem, which hasn't been fixed. I know that we are
using not the very recent libc, but I like to find out where
the problem is anyhow.

We are using a plain SuSE 7.0 with a libc-2.1.3.
We have 2 groups with more than 700 chars, as soon as
we enable the compat or nisplus mode  in /etc/nsswitch.conf for
groups we get segfaults while authenticating. also the strace
output makes us assuming  that  there is a bug. No problem if
we dump the NIS+ groups and append it to /etc/group.

So, how can we find the bug and to fix it in libc 2.1.3 ??

Looks like other people have the same problem:

http://lists.samba.org/pipermail/linux-nisplus/2000-June/000398.html
http://lists.samba.org/pipermail/linux-nisplus/2000-August/000416.html


thx,
        Dirk



------------------------------------------------
Thorsten Kukuk address@hidden
Wed, 15 Nov 2000 09:31:49 +0100

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Hi,

On Tue, Nov 14, Morong, Gerry wrote:

> Looking into why accessing UNIX group information for large groups
causes
> logins to fail when using NIS+.  If you put the same large group in
> /etc/group and remove it from NIS+ everything works fine.   Noticed
that the
> function _nss_nisplus_parse_grent  in
> /usr/src/redhat/BUILD/glibc-2.1/nis/nss_nisplus/nisplus-parser.c is
> concerned about the size of buflen (size_t).  Seems to be set to 1024
but
> somewhere around 650 characters in the group entry I have the problem.

> Trying to figure out what code upstream is setting the 1024 limit and
why it
> does not affect large groups in the local group file.   Is this an
issue
> with NSS?

There is no buffer limit in this function. If the buffer is to small,
it gives back an error and the calling program/function (depending which

interface your program uses) must allocate more buffer.

There where some NSS bugs in older glibc versions, but there should be
no
problem with the official released glibc 2.1.3 or 2.2.

  Thorsten

--
Thorsten Kukuk       http://www.suse.de/~kukuk/       address@hidden
SuSE GmbH            Schanzaeckerstr. 10            90443 Nuernberg
Linux is like a Vorlon.  It is incredibly powerful, gives terse,
cryptic answers and has a lot of things going on in the background.