From: Dominick Grift <dominick.grift@defensec.nl>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: selinux@vger.kernel.org
Subject: Re: question about fs sid
Date: Mon, 27 Jan 2020 15:08:25 +0100 [thread overview]
Message-ID: <20200127140825.GB1998492@brutus.lan> (raw)
In-Reply-To: <e09a265c-83ad-8422-a67b-24b265ab8381@tycho.nsa.gov>
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On Mon, Jan 27, 2020 at 08:55:00AM -0500, Stephen Smalley wrote:
> On 1/27/20 7:52 AM, Dominick Grift wrote:
> > What is the fs sid used for exactly? What, if any, is its relationship with persistent file systems with xattr support.
> > Were currently associating a type that is generally also associated with persistent filesystems that support xattr but i dont know why.
> > Why would it not apply to other filesystems, for example tmpfs or vfat or whatever?
> >
> > Is the fs sid still used and what do i need to consider when determining what context to associate with it?
>
> Are you referring to the fs initial SID, or to the SID associated with each
> filesystem/superblock?
Thanks. Yes was referring to the fs initial sid.
I now moved it to the list of unused_isids. I'll see if that works
>
> The former appears to be unused by any kernel code other than the
> declaration (grep -r SECINITSID_FS). At one time, it was the default SID to
> use for the filesystem/superblock. Looks like this has never been used in
> mainline Linux, just pre-mainline SELinux. Sadly we cannot just remove
> obsolete initial SIDs until we fix
> https://github.com/SELinuxProject/selinux-kernel/issues/12
>
> The latter is still relevant but the defaults are now determined through
> fs_use_* or genfscon statements, default to the unlabeled SID if there is no
> match, and can be overridden via the fscontext= mount option. It is used in
> permission checks on the superblock/filesystem (e.g. mount, unmount, ...)
> and to limit what file contexts can be assigned to files within the
> filesystem (associate).
--
gpg --locate-keys dominick.grift@defensec.nl
Key fingerprint = FCD2 3660 5D6B 9D27 7FC6 E0FF DA7E 521F 10F6 4098
Dominick Grift
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prev parent reply other threads:[~2020-01-27 14:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 12:52 question about fs sid Dominick Grift
2020-01-27 13:55 ` Stephen Smalley
2020-01-27 14:08 ` Dominick Grift [this message]
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