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

From: Mimi Zohar
Date: Wed Dec 20 2023 - 09:20:00 EST


On Wed, 2023-12-20 at 13:35 +0100, Christian Brauner wrote:
> 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,

Thanks, Christian.

>
> Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>