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From:   Matthew Garrett <mjg59@srcf.ucam.org>
To:     Aditya Garg <gargaditya08@live.com>
Cc:     Ard Biesheuvel <ardb@kernel.org>, Jeremy Kerr <jk@ozlabs.org>,
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Subject: Re: [PATCH] efi: Do not import certificates from UEFI Secure Boot
 for T2 Macs
Message-ID: <20220212194240.GA4131@srcf.ucam.org>
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On Sat, Feb 12, 2022 at 05:53:47AM +0000, Aditya Garg wrote:

> Feb 12 11:01:52 MacBook kernel: Reading EFI variable db-d719b2cb-3d3a-4596-a3bc-dad00e67656f

Ok. With CONFIG_LOAD_UEFI_KEYS=n, can you run:

cat /sys/firmware/efi/efivars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f

and see whether it generates the same failure? If so then my (handwavy) 
guess is that something's going wrong with a firmware codepath for the 
d719b2cb-3d3a-4596-a3bc-dad00e67656f GUID. Someone could potentially 
then figure out whether the same happens under Windows, but the easiest 
thing is probably to just return a failure on Apple hardware when 
someone tries to access anything with that GUID.