updpwd AVC

Tue Sep 27 18:17:17 UTC 2011

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On 09/27/2011 11:26 AM, Tony Molloy wrote:
> On Monday 26 September 2011 22:22:31 Dominick Grift wrote:
> 
>> On Mon, 2011-09-26 at 15:00 +0100, Tony Molloy wrote:
> 
>>> Hi,
> 
>>> 
> 
>>> 
> 
>>> On a fully updated CentOS 5.7 box I get the following AVC
> 
>>> 
> 
>>> 
> 
>>> Summary:
> 
>>> 
> 
>>> 
> 
>>> SELinux is preventing unix_update (updpwd_t) "getattr" to /
> 
>>> (fs_t).
> 
>>> 
> 
>>> 
> 
>>> Detailed Description:
> 
>>> 
> 
>>> 
> 
>>> SELinux denied access requested by unix_update. It is not
> 
>>> expected that this
> 
>>> 
> 
>>> access is required by unix_update and this access may signal
>>> an
> 
>>> intrusion
> 
>>> 
> 
>>> attempt. It is also possible that the specific version or
> 
>>> configuration of the
> 
>>> 
> 
>>> application is causing it to require additional access.
> 
>>> 
> 
>>> 
> 
>>> Allowing Access:
> 
>>> 
> 
>>> 
> 
>>> You can generate a local policy module to allow this access -
>>> see
> 
>>> FAQ
> 
>>> 
> 
>>> (http://fedora.redhat.com/docs/selinux-faq-fc5/#id2961385) Or
>>> you
> 
>>> can disable
> 
>>> 
> 
>>> SELinux protection altogether. Disabling SELinux protection is
> 
>>> not recommended.
> 
>>> 
> 
>>> Please file a bug report
> 
>>> (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi)
> 
>>> 
> 
>>> against this package.
> 
>>> 
> 
>>> 
> 
>>> Additional Information:
> 
>>> 
> 
>>> 
> 
>>> Source Context system_u:system_r:updpwd_t
> 
>>> 
> 
>>> Target Context system_u:object_r:fs_t
> 
>>> 
> 
>>> Target Objects / [ filesystem ]
> 
>>> 
> 
>>> Source unix_update
> 
>>> 
> 
>>> Source Path <Unknown>
> 
>>> 
> 
>>> Port <Unknown>
> 
>>> 
> 
>>> Host a.b.c.d
> 
>>> 
> 
>>> Source RPM Packages
> 
>>> 
> 
>>> Target RPM Packages filesystem-2.4.0-3.el5.centos
> 
>>> 
> 
>>> Policy RPM selinux-policy-2.4.6-316.el5
> 
>>> 
> 
>>> Selinux Enabled True
> 
>>> 
> 
>>> Policy Type targeted
> 
>>> 
> 
>>> MLS Enabled True
> 
>>> 
> 
>>> Enforcing Mode Enforcing
> 
>>> 
> 
>>> Plugin Name catchall
> 
>>> 
> 
>>> Host Name a.b.c.d
> 
>>> 
> 
>>> Platform Linuxl a.b.c.d 2.6.18-274.3.1.el5
> 
>>> 
> 
>>> #1 SMP Tue Sep 6 20:13:52 EDT 2011 x86_64 x86_64
> 
>>> 
> 
>>> Alert Count 11
> 
>>> 
> 
>>> First Seen Fri Feb 25 15:39:33 2011
> 
>>> 
> 
>>> Last Seen Mon Sep 26 14:18:54 2011
> 
>>> 
> 
>>> Local ID 275eef01-114a-419b-9df0-4bb81932bc5e
> 
>>> 
> 
>>> Line Numbers
> 
>>> 
> 
>>> 
> 
>>> Raw Audit Messages
> 
>>> 
> 
>>> 
> 
>>> host=a.b.c.d type=AVC msg=audit(1317043134.620:3620): avc:
>>> denied
> 
>>> { getattr } for pid=21354 comm="unix_update" name="/" dev=sda5
> 
>>> ino=2 scontext=system_u:system_r:updpwd_t:s0
> 
>>> tcontext=system_u:object_r:fs_t:s0 tclass=filesystem
> 
>>> 
> 
>>> 
> 
>>> 
> 
>>> I can generate a local policy module.
> 
>> 
> 
>> Any idea what you were doing when this happened? The reason i
>> ask
> 
>> is because this is not even allowed in latest fedora as far as i
> 
>> can see.
> 
>> 
> 
> 
> This machine is basically a mail and ftp server. As far as I can
> tell from the logs ( secure and messages ) nobody was doing
> anything on the machine at the times I get the AVC, 5 times
> yesterday.
> 
> 
>> It is no big deal to allow updpwd_t to get attributes of the
>> fs_t
> 
>> filesystem but it is certainly not common for updpwd_t to want
>> this
> 
>> access i believe. If it was we probably would have gotten may
>> more
> 
>> reports much earlier.
> 
>> 
> 
> 
> Strange then that I am getting it from this one server only.
> 
> 
> Here's the context for unix_update
> 
> 
> -rwx------ root root system_u:object_r:updpwd_exec_t
> /sbin/unix_update
> 
> 
> I've just run an autorelabel on the entire filesystem as part of
> the 5.6 to 5.7 CentOS update
> 
> 
> Thanks,
> 
> 
> Tony
> 
> 
>>> Thanks,
> 
>>> 
> 
>>> 
> 
>>> Tony
> 
>>> 
> 
>>> --
> 
>>> selinux mailing list
> 
>>> selinux at lists.fedoraproject.org
> 
>>> https://admin.fedoraproject.org/mailman/listinfo/selinux
> 
> 
> 
> 
> -- selinux mailing list selinux at lists.fedoraproject.org 
> https://admin.fedoraproject.org/mailman/listinfo/selinux

Probably has to do with the way the mount table is setup on this
machine versus other machines.
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