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Subject: Re: [PATCH v2 00/15] ima: digest list feature
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Matthew Garrett <mjg59@google.com>,
        Roberto Sassu <roberto.sassu@huawei.com>
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On Thu, 2017-11-09 at 09:47 -0500, Matthew Garrett wrote:

> This seems very over-complicated, and it's unclear why the kernel
> needs to open the file itself. You *know* that all of userland is
> trustworthy at this point even in the absence of signatures.

Assuming the initramfs is signed, then yes the rootfs files would be
trusted.  rootfs can still access files from real root, which is where
policies are normally stored.

> It seems
> reasonable to provide a interface that allows userland to pass a
> digest list to the kernel, in the same way that userland can pass an
> IMA policy to the kernel. You can then restrict access to that
> interface via an LSM.

IMA can and should be configured to require signed policies.

Mimi