[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4EE1146C.2090808@redhat.com>
Date: Thu, 08 Dec 2011 12:47:56 -0700
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security@...ts.openwall.com
CC: Jeff Mitchell <mitchell@....org>
Subject: Re: Disputing CVE-2011-4122
On 12/08/2011 07:11 AM, Jeff Mitchell wrote:
> On 12/07/2011 11:26 AM, Kurt Seifried wrote:
>>> One could assume that kcheckpass should do the validation. However, the
>>> PAM documentation makes no mention of what a service name is supposed to
>>> look like, and consequently it must be treated as opaque by the
>>> application code. Therefore all validation must be expected to be done
>>> by the library, and failure to do so must be seen as a bug in the
>>> library exclusively.
>>
>> Can you provide a link to the documentation?
>
> http://pubs.opengroup.org/onlinepubs/8329799/pam_start.htm
>
> Thanks,
> Jeff
>
Looking around I did find:
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/3/html/Reference_Guide/s1-pam-config-files.html
=====================
15.2.1. PAM Service Files
Each PAM-aware application or service has a file within the /etc/pam.d/
directory. Each file within this directory bears the name of the service
for which it controls access.
It is up to the PAM-aware program to define its service name and install
its own PAM configuration file in the /etc/pam.d/ directory. For
example, the login program defines its service name as login and
installs the /etc/pam.d/login PAM configuration file.
=====================
so to some degree it is defined: the service name must fit legal file
name constraints, but this means things like length, but on ext4 for
example this means 256 chars max, and only NULL and "/" are disallowed,
to say nothing of other file systems like xfs (any bytes except null)
and Joliet (CDFS, max 64 characters, unicode supported[1])
So perhaps going for a lowest common denominator of common filesystems
you'd expect to find /etc/ on (so ext4, xfs, maybe Joliet for cd based
systems?) as a filter would be appropriate? And poking the PAM people to
refine the specification a little bit? Thoughts or comments anyone?
[1] http://en.wikipedia.org/wiki/Comparison_of_file_systems
--
-Kurt Seifried / Red Hat Security Response Team
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
