Re: [Qemu-devel] [PATCH v3 7/7] OvmfPkg: plug DxeTpm2MeasureBootLib into SecurityStubDxe

[Laszlo Ersek]

On 03/09/18 14:09, address@hidden wrote:
> From: Marc-André Lureau <address@hidden>
> 
> The library registers a security management handler, to measure images
> that are not measure in PEI phase. For example with the qemu PXE rom:
> 
> Loading driver at 0x0003E6C2000 EntryPoint=0x0003E6C9076 8086100e.efi
> 
> And the following binary_bios_measurements log entry seems to be
> added:
> 
> PCR: 2        type: EV_EFI_BOOT_SERVICES_DRIVER       size: 0x4e      digest: 
> 70a22475e9f18806d2ed9193b48d80d26779d9a4
> 
> The following order of operations ensures that 3rd party UEFI modules,
> such as PCI option ROMs and other modules possibly loaded from outside
> of firmware volumes, are measured into the TPM:
> 
> (1) Tcg2Dxe is included in DXEFV, therefore it produces the TCG2
>     protocol sometime in the DXE phase (assuming a TPM2 chip is present,
>     reported via PcdTpmInstanceGuid).
> 
> (2) The DXE core finds that no more drivers are left to dispatch from
>     DXEFV, and we enter the BDS phase.
> 
> (3) OVMF's PlatformBootManagerLib connects all PCI root bridges
>     non-recursively, producing PciIo instances and discovering PCI
>     oproms.
> 
> (4) The dispatching of images that don't originate from FVs is deferred
>     at this point, by
>     "MdeModulePkg/Universal/SecurityStubDxe/Defer3rdPartyImageLoad.c".
> 
> (5) OVMF's PlatformBootManagerLib signals EndOfDxe.
> 
> (6) OVMF's PlatformBootManagerLib calls
>     EfiBootManagerDispatchDeferredImages() -- the images deferred in
>     step (4) are now dispatched.
> 
> (7) Image dispatch invokes the Security / Security2 Arch protocols
>     (produced by SecurityStubDxe). In this patch, we hook
>     DxeTpm2MeasureBootLib into SecurityStubDxe, therefore image dispatch
>     will try to locate the TCG2 protocol, and measure the image into the
>     TPM2 chip with the protocol. Because of step (1), the TCG2 protocol
>     will always be found and used (assuming a TPM2 chip is present).
> 
> Cc: Laszlo Ersek <address@hidden>
> Cc: Stefan Berger <address@hidden>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  OvmfPkg/OvmfPkgIa32.dsc    | 3 +++
>  OvmfPkg/OvmfPkgIa32X64.dsc | 3 +++
>  OvmfPkg/OvmfPkgX64.dsc     | 3 +++
>  3 files changed, 9 insertions(+)
> 
> diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
> index f80fb50d4a38..92c8c560a067 100644
> --- a/OvmfPkg/OvmfPkgIa32.dsc
> +++ b/OvmfPkg/OvmfPkgIa32.dsc
> @@ -644,6 +644,9 @@ [Components]
>      <LibraryClasses>
>  !if $(SECURE_BOOT_ENABLE) == TRUE
>        
> NULL|SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.inf
> +!endif
> +!if $(TPM2_ENABLE) == TRUE
> +      
> NULL|SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.inf
>  !endif
>    }
>  
> diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
> index bc48b5b63c7a..6ecaa795b288 100644
> --- a/OvmfPkg/OvmfPkgIa32X64.dsc
> +++ b/OvmfPkg/OvmfPkgIa32X64.dsc
> @@ -653,6 +653,9 @@ [Components.X64]
>      <LibraryClasses>
>  !if $(SECURE_BOOT_ENABLE) == TRUE
>        
> NULL|SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.inf
> +!endif
> +!if $(TPM2_ENABLE) == TRUE
> +      
> NULL|SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.inf
>  !endif
>    }
>  
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index e89de093d6a2..c98a3657c6f6 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -651,6 +651,9 @@ [Components]
>      <LibraryClasses>
>  !if $(SECURE_BOOT_ENABLE) == TRUE
>        
> NULL|SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.inf
> +!endif
> +!if $(TPM2_ENABLE) == TRUE
> +      
> NULL|SecurityPkg/Library/DxeTpm2MeasureBootLib/DxeTpm2MeasureBootLib.inf
>  !endif
>    }
>  
> 

Reviewed-by: Laszlo Ersek <address@hidden>