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Re: devfs mysterious relabelling

To: Stephen Smalley <sds@xxxxxxxxxxx>
Subject: Re: devfs mysterious relabelling
From: Russell Coker <russell@xxxxxxxxxxxx>
Date: Tue, 28 May 2002 15:27:23 +0200
Cc: SE Linux <selinux@xxxxxxxxxxxxx>, devfs@xxxxxxxxxxx
In-reply-to: <Pine.GSO.4.33.0205280903080.1315-100000@raven>
References: <Pine.GSO.4.33.0205280903080.1315-100000@raven>
Reply-to: Russell Coker <russell@xxxxxxxxxxxx>
Sender: owner-devfs@xxxxxxxxxxx
On Tue, 28 May 2002 15:04, Stephen Smalley wrote:
> On Fri, 24 May 2002, Russell Coker wrote:
> > On my systems I have devfsd do most of the device node labelling.
> >
> > I have noticed that often the system_u:object_r:fixed_disk_device_t
> > labels (for /dev/ide/host0/bus0/target0/lun0/*) will get changed to
> > system_u:object_r:devfs_t (the default context for devfs).
> >
> > It doesn't happen to the device node for the entire file system
> > /dev/ide/host0/bus0/target0/lun0/disc and the device node
> > /dev/ide/host0/bus0/target0/lun0/part5 (an extended partition).
> >
> > I believe that this is not a user-land issue, and it's something in the
> > kernel (but I have not proven this yet).
> >
> > Also it seems to happen more often when under load (setfiles on the root
> > file system usually does the job).
>
> This could happen if a devfs entry is evicted from the dcache and is later
> looked up again, causing the security context to be re-acquired from the
> devfs_contexts configuration.  Doesn't this issue also arise for the
> ownership and mode on devfs entries when they are managed by devfsd?

No!  Devfs preserves the results of chmod/chown operations until the next 
reboot.

I'm surprised though, I thought that devfs entries would be locked in the 
dcache...

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