linux-kernel - Re: [PATCH v2 0/3] evm: disable EVM on overlayfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Wed, 20 Dec 2023 13:35:40 +0100
From: Christian Brauner <brauner@...nel.org>
To: Mimi Zohar <zohar@...ux.ibm.com>
Cc: linux-unionfs@...r.kernel.org, linux-integrity@...r.kernel.org,
	linux-kernel@...r.kernel.org, Amir Goldstein <amir73il@...il.com>,
	Seth Forshee <sforshee@...nel.org>,
	Roberto Sassu <roberto.sassu@...weicloud.com>
Subject: Re: [PATCH v2 0/3] evm: disable EVM on overlayfs

On Tue, Dec 19, 2023 at 12:52:03PM -0500, Mimi Zohar wrote:
> EVM verifies the existing 'security.evm' value, before allowing it
> to be updated.  The EVM HMAC and the original file signatures contain
> filesystem specific metadata (e.g. i_ino, i_generation and s_uuid).
> 
> This poses a challenge when transitioning from the lower backing file
> to the upper backing file.
> 
> Until a complete solution is developed, disable EVM on overlayfs.
> 
> Changelog v2:
> Addressed Amir's comments:
> - Simplified security_inode_copy_up_xattr() return.
> - Identified filesystems that don't support EVM based on a new SB_I flag.

We're wasting a flag for a single filesystem but we do have enough of
them left so I think this is ok,

Reviewed-by: Christian Brauner <brauner@...nel.org>