From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mx.groups.io with SMTP id smtpd.web08.4606.1622108512008810081 for ; Thu, 27 May 2021 02:41:52 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=YQa91Z9j; spf=pass (domain: redhat.com, ip: 170.10.133.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622108511; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TcZXNr68Gkqlg+q/V7YOUA7YaSUDg8MtNKDopTCa5Cc=; b=YQa91Z9jL1Rfcwuesaj/wuhleZosggjkgB5VyFH/BeuMLdDLEniC609Bm5vbFZ4Q2tLZ/1 P1E8+9VvGgQGBy958MmZjDt3lxCTJHw87Msr//S0JoaJxSXkravIrsCdVLBEN1buHv8wvL u6FDqwciiO7nN5y1nx3NDfC0LDH1ipQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-518-MwProZJDOGyCdjC2KXalug-1; Thu, 27 May 2021 05:41:49 -0400 X-MC-Unique: MwProZJDOGyCdjC2KXalug-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AC64979ECE; Thu, 27 May 2021 09:41:47 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-115-44.ams2.redhat.com [10.36.115.44]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 66F3F5DEC1; Thu, 27 May 2021 09:41:44 +0000 (UTC) Subject: Re: [edk2-devel] [PATCH v1 0/8] Measured SEV boot with kernel/initrd/cmdline To: devel@edk2.groups.io, dovmurik@linux.ibm.com Cc: Tobin Feldman-Fitzthum , Tobin Feldman-Fitzthum , Jim Cadden , James Bottomley , Hubertus Franke , Ard Biesheuvel , Jordan Justen , Ashish Kalra , Brijesh Singh , Erdem Aktas , Jiewen Yao , Min Xu , Tom Lendacky References: <20210525053116.1533673-1-dovmurik@linux.ibm.com> From: "Laszlo Ersek" Message-ID: <61581474-7434-8d88-385b-c1bcdfde0569@redhat.com> Date: Thu, 27 May 2021 11:41:42 +0200 MIME-Version: 1.0 In-Reply-To: <20210525053116.1533673-1-dovmurik@linux.ibm.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 05/25/21 07:31, Dov Murik wrote: > Booting with SEV prevented the loading of kernel, initrd, and kernel > command-line via QEMU fw_cfg interface because they arrive from the VMM > which is untrusted in SEV. > > However, in some cases the kernel, initrd, and cmdline are not secret > but should not be modified by the host. In such a case, we want to > verify inside the trusted VM that the kernel, initrd, and cmdline are > indeed the ones expected by the Guest Owner, and only if that is the > case go on and boot them up (removing the need for grub inside OVMF in > that mode). > > This patch series declares a new page in MEMFD which will contain the > hashes of these three blobs (kernel, initrd, cmdline), each under its > own GUID entry. This tables of hashes is populated by QEMU before > launch, and encrypted as part of the initial VM memory; this makes sure > theses hashes are part of the SEV measurement (which has to be approved > by the Guest Owner for secret injection, for example). Note that this > requires a new QEMU patch which will be submitted soon. > > OVMF parses the table of hashes populated by QEMU (patch 5), and as it > reads the fw_cfg blobs from QEMU, it will verify each one against the > expected hash (kernel and initrd verifiers are introduced in patch 6, > and command-line verifier is introduced in patches 7+8). This is all > done inside the trusted VM context. If all the hashes are correct, boot > of the kernel is allowed to continue. > > Any attempt by QEMU to modify the kernel, initrd, cmdline (including > dropping one of them), or to modify the OVMF code that verifies those > hashes, will cause the initial SEV measurement to change and therefore > will be detectable by the Guest Owner during launch before secret > injection. > > Cc: Laszlo Ersek > Cc: Ard Biesheuvel > Cc: Jordan Justen > Cc: Ashish Kalra > Cc: Brijesh Singh > Cc: Erdem Aktas > Cc: James Bottomley > Cc: Jiewen Yao > Cc: Min Xu > Cc: Tom Lendacky > > James Bottomley (8): > OvmfPkg/AmdSev/SecretDxe: fix header comment to generic naming > OvmfPkg: PlatformBootManagerLibGrub: Allow executing kernel via fw_cfg > OvmfPkg/AmdSev: add a page to the MEMFD for firmware config hashes > OvmfPkg/QemuKernelLoaderFsDxe: Add ability to verify loaded items > OvmfPkg/AmdSev: Add library to find encrypted hashes for the FwCfg > device > OvmfPkg/AmdSev: Add firmware file plugin to verifier > OvmfPkg: GenericQemuLoadImageLib: Allow verifying fw_cfg command line > OvmfPkg/AmdSev: add SevQemuLoadImageLib > > OvmfPkg/OvmfPkg.dec | 10 ++ > OvmfPkg/AmdSev/AmdSevX64.dsc | 9 +- > OvmfPkg/AmdSev/AmdSevX64.fdf | 3 + > OvmfPkg/AmdSev/Library/SevFwCfgVerifier/SevFwCfgVerifier.inf | 30 +++++ > OvmfPkg/AmdSev/Library/SevHashFinderLib/SevHashFinderLib.inf | 34 ++++++ > OvmfPkg/AmdSev/Library/SevQemuLoadImageLib/SevQemuLoadImageLib.inf | 30 +++++ > OvmfPkg/Library/PlatformBootManagerLibGrub/PlatformBootManagerLibGrub.inf | 2 + > OvmfPkg/ResetVector/ResetVector.inf | 2 + > OvmfPkg/AmdSev/Include/Library/SevHashFinderLib.h | 47 ++++++++ > OvmfPkg/Include/Library/QemuFwCfgLib.h | 35 ++++++ > OvmfPkg/Library/PlatformBootManagerLibGrub/BdsPlatform.h | 11 ++ > OvmfPkg/AmdSev/Library/SevFwCfgVerifier/SevFwCfgVerifier.c | 60 ++++++++++ > OvmfPkg/AmdSev/Library/SevHashFinderLib/SevHashFinderLib.c | 126 ++++++++++++++++++++ > OvmfPkg/AmdSev/Library/SevQemuLoadImageLib/SevQemuLoadImageLib.c | 52 ++++++++ > OvmfPkg/AmdSev/SecretDxe/SecretDxe.c | 2 +- > OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c | 29 +++++ > OvmfPkg/Library/PlatformBootManagerLibGrub/BdsPlatform.c | 5 + > OvmfPkg/Library/PlatformBootManagerLibGrub/QemuKernel.c | 50 ++++++++ > OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c | 31 +++++ > OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 20 ++++ > OvmfPkg/ResetVector/ResetVector.nasmb | 2 + > 21 files changed, 587 insertions(+), 3 deletions(-) > create mode 100644 OvmfPkg/AmdSev/Library/SevFwCfgVerifier/SevFwCfgVerifier.inf > create mode 100644 OvmfPkg/AmdSev/Library/SevHashFinderLib/SevHashFinderLib.inf > create mode 100644 OvmfPkg/AmdSev/Library/SevQemuLoadImageLib/SevQemuLoadImageLib.inf > create mode 100644 OvmfPkg/AmdSev/Include/Library/SevHashFinderLib.h > create mode 100644 OvmfPkg/AmdSev/Library/SevFwCfgVerifier/SevFwCfgVerifier.c > create mode 100644 OvmfPkg/AmdSev/Library/SevHashFinderLib/SevHashFinderLib.c > create mode 100644 OvmfPkg/AmdSev/Library/SevQemuLoadImageLib/SevQemuLoadImageLib.c > create mode 100644 OvmfPkg/Library/PlatformBootManagerLibGrub/QemuKernel.c > I'm confirming that this series is in my review queue. However, I may need unusually long time to get to it. Thanks for your patience. Thanks Laszlo