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Date: Tue, 2 Nov 2021 11:05:57 +0100
From: "Gerd Hoffmann" <kraxel@redhat.com>
To: Dov Murik <dovmurik@linux.ibm.com>
Cc: devel@edk2.groups.io, Ard Biesheuvel <ardb+tianocore@kernel.org>,
	Jordan Justen <jordan.l.justen@intel.com>,
	Brijesh Singh <brijesh.singh@amd.com>,
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	Tom Lendacky <thomas.lendacky@amd.com>,
	Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
Subject: Re: [PATCH] OvmfPkg/AmdSev: Erase secret area content on ExitBootServices
Message-ID: <20211102100557.tcv5mfz2rpnmcrpa@sirius.home.kraxel.org>
References: <20211102082506.366921-1-dovmurik@linux.ibm.com>
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On Tue, Nov 02, 2021 at 08:25:06AM +0000, Dov Murik wrote:
> The confidential computing secrets area is marked as EfiBootServicesData
> region, which means it is released for the OS use when the OS EFI stub
> calls ExitBootServices.  However, its content is not erased, and
> therefore the OS might unintentionally reuse this sensitive memory area
> and expose the injected secrets.
> 
> Erase the content of the secret area on ExitBootServices so that the
> memory released to the OS contains zeros.  If the OS needs to keep the
> secrets for its own use, it must copy the secrets area to another memory
> area before calling ExitBootServices (for example in efi/libstub in
> Linux).

Acked-by: Gerd Hoffmann <kraxel@redhat.com>

take care,
  Gerd