Re: [PATCH 0/3] Add O_DENY* flags to fcntl and cifs

From: Alan Cox
Date: Thu Dec 06 2012 - 14:44:24 EST


On Thu, 6 Dec 2012 22:26:28 +0400
Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:

> Network filesystems CIFS, SMB2.0, SMB3.0 and NFSv4 have such flags - this change can benefit cifs and nfs modules. While this change is ok for network filesystems, itsn't not targeted for local filesystems due security problems (e.g. when a user process can deny root to delete a file).

If I have my root fs on NFS then the same applies does it not.

Your patches fail to describe the security semantics and what file rights
I must have to apply each option. How do I track down a lock user, what
tools are provided ? How do the new options interact with the security
layer?

I don't have a problem with the idea, but it needs a lot more clear
description of how it works so the model can be checked and if need be
things tweaked (eg needing write to denywrite etc)

Alan
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