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From: Mimi Zohar <zohar@linux.ibm.com>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org, linux-integrity@vger.kernel.org
Subject: Re: [PATCH RFC 0/4] IMA on NFS prototype
Date: Wed, 20 Feb 2019 07:26:36 -0500	[thread overview]
Message-ID: <1550665596.17768.32.camel@linux.ibm.com> (raw)
In-Reply-To: <ABC54315-2F2B-4FA7-98A8-28A3FC2092DB@oracle.com>

On Tue, 2019-02-19 at 22:51 -0500, Chuck Lever wrote:
> > On Feb 19, 2019, at 7:36 PM, Mimi Zohar <zohar@linux.ibm.com> wrote:
> > 
> > Hi Chuck,
> > 
> >> EVM is not supported in this prototype. NFS does not support several
> >> of the xattrs that are protected by EVM: SMACK64, Posix ACLs, and
> >> Linux file capabilities are not supported, which makes EVM more
> >> difficult to support on NFS mounts.
> > 
> > There's no requirement for all of these xattrs to exist.  If an xattr
> > does exist, then it is included in the security.evm hmac/signature.
> 
> Understood. The issue is that if they exist on a file residing on an NFS server,
> such xattrs would not be visible to clients. My understanding is that then EVM
> verification would fail on such files on NFS clients.
> 
> We could possibly make EVM work in limited scenarios until such time that
> the NFS protocol can make those xattrs available to NFS clients. I hope that
> having only security.ima is useful at least for experimenting and maybe more.
> 
> However, if folks think having security.evm also is needed, that is straight-
> forward... just saying that there are currently other limits in NFS that make a
> full EVM implementation problematic.

Thank you for the explanation.  Yes, I think there is a benefit of
having a file signature, without EVM.

Mimi


  reply	other threads:[~2019-02-20 12:26 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-14 20:43 [PATCH RFC 0/4] IMA on NFS prototype Chuck Lever
2019-02-14 20:43 ` [PATCH RFC 1/4] NFS: Define common IMA-related protocol elements Chuck Lever
2019-02-14 20:43 ` [PATCH RFC 2/4] NFS: Rename security xattr handler Chuck Lever
2019-02-14 20:43 ` [PATCH RFC 3/4] NFS: Prototype support for IMA on NFS (client) Chuck Lever
2019-02-14 20:43 ` [PATCH RFC 4/4] NFSD: Prototype support for IMA on NFS (server) Chuck Lever
2019-02-18 19:32   ` J. Bruce Fields
2019-02-18 19:41     ` Chuck Lever
2019-03-01 15:04       ` Bruce Fields
2019-03-01 16:01         ` Chuck Lever
2019-03-01 16:10           ` Bruce Fields
2019-02-20  0:36 ` [PATCH RFC 0/4] IMA on NFS prototype Mimi Zohar
2019-02-20  3:51   ` Chuck Lever
2019-02-20 12:26     ` Mimi Zohar [this message]
2019-02-21 14:49       ` Chuck Lever
2019-02-21 15:51         ` Mimi Zohar
2019-02-21 15:58           ` Chuck Lever
2019-02-22 20:16             ` J. Bruce Fields

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