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Date:   Sun, 23 Jun 2019 13:08:52 +0200 (CEST)
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Matthew Garrett <matthewgarrett@google.com>
cc:     jmorris@namei.org, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        David Howells <dhowells@redhat.com>,
        Matthew Garrett <mjg59@google.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org
Subject: Re: [PATCH V34 20/29] x86/mmiotrace: Lock down the testmmiotrace
 module
In-Reply-To: <20190622000358.19895-21-matthewgarrett@google.com>
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References: <20190622000358.19895-1-matthewgarrett@google.com> <20190622000358.19895-21-matthewgarrett@google.com>
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On Fri, 21 Jun 2019, Matthew Garrett wrote:

> From: David Howells <dhowells@redhat.com>
> 
> The testmmiotrace module shouldn't be permitted when the kernel is locked
> down as it can be used to arbitrarily read and write MMIO space. This is
> a runtime check rather than buildtime in order to allow configurations
> where the same kernel may be run in both locked down or permissive modes
> depending on local policy.
> 
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: David Howells <dhowells@redhat.com
> Signed-off-by: Matthew Garrett <mjg59@google.com>
> cc: Thomas Gleixner <tglx@linutronix.de>
> cc: Steven Rostedt <rostedt@goodmis.org>
> cc: Ingo Molnar <mingo@kernel.org>
> cc: "H. Peter Anvin" <hpa@zytor.com>
> cc: x86@kernel.org

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>