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Revert "OvmfPkg: use generic QEMU image loader for secure boot enabled ..." 

This reverts commit ced77332ca.

The command

  virt-install --location NETWORK-URL

downloads the vmlinuz and initrd files from the remote OS tree, and passes
them to the guest firmware via fw_cfg.

When used with IA32 / X64 guests, virt-install expects the guest firmware
to do two things, at the same time:

- launch the fw_cfg kernel image even if the latter does not pass SB
  verification (SB checking is supposed to be bypassed entirely in favor
  of the Linux/x86 Boot Protocol),

- still let the guest kernel perceive SB as enabled.

Commit ced77332ca prevented this, by removing the Linux/x86 Boot
Protocol from such an OVMF image that was built with SECURE_BOOT_ENALBE.
While that's the right thing in theory, in practice "virt-install
--location NETWORK-URL" is entrenched, and we shouldn't break it.

We can tolerate the Linux/x86 Boot Protocol as a one-of-a-kind SB bypass
for direct-booted kernels, because:

- the fw_cfg content comes from QEMU, and the guest is already at QEMU's
  mercy,

- in the guest, OS boots after the initial installation will use "shim"
  rather than an fw_cfg kernel, which we can consider somewhat similar to
  "Audit Mode / Deployed Mode" (~ trust for install, lock down after).

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Message-Id: <20200615144514.24597-1-lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[lersek@redhat.com: truncate the subject line, originally auto-generated
 by git-revert, to pacify PatchCheck.py]
This commit is contained in:
Laszlo Ersek 2020-06-15 16:45:14 +02:00 committed by mergify[bot]
parent 493f2c6931
commit 82808b4226
3 changed files with 0 additions and 12 deletions
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4
OvmfPkg/OvmfPkgIa32.dsc
View File

@ -379,11 +379,7 @@
PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
!if $(SECURE_BOOT_ENABLE) == TRUE
QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
!else
QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
!endif
!if $(TPM_ENABLE) == TRUE
Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf

4
OvmfPkg/OvmfPkgIa32X64.dsc
View File

@ -383,11 +383,7 @@
PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
!if $(SECURE_BOOT_ENABLE) == TRUE
QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
!else
QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
!endif
!if $(TPM_ENABLE) == TRUE
Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf

4
OvmfPkg/OvmfPkgX64.dsc
View File

@ -383,11 +383,7 @@
PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
!if $(SECURE_BOOT_ENABLE) == TRUE
QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
!else
QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
!endif
!if $(TPM_ENABLE) == TRUE
Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf