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OvmfPkg/X86QemuLoadImageLib: handle EFI_ACCESS_DENIED from LoadImage() 

When an image fails Secure Boot validation, LoadImage() returns
EFI_SECURITY_VIOLATION if the platform policy is
DEFER_EXECUTE_ON_SECURITY_VIOLATION.

If the platform policy is DENY_EXECUTE_ON_SECURITY_VIOLATION, then
LoadImage() returns EFI_ACCESS_DENIED (and the image does not remain
loaded).

(Before <https://bugzilla.tianocore.org/show_bug.cgi?id=2129>, this
difference would be masked, as DxeImageVerificationLib would incorrectly
return EFI_SECURITY_VIOLATION for DENY_EXECUTE_ON_SECURITY_VIOLATION as
well.)

In X86QemuLoadImageLib, proceed to the legacy Linux/x86 Boot Protocol upon
seeing EFI_ACCESS_DENIED too.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2785
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200605235242.32442-1-lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
This commit is contained in:
Laszlo Ersek 2020-06-06 01:52:42 +02:00 committed by mergify[bot]
parent 82e0b2f043
commit dafce295e6
1 changed files with 10 additions and 4 deletions
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14
OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
View File

@ -320,15 +320,21 @@ QemuLoadKernelImage (
case EFI_SECURITY_VIOLATION:
//
// We are running with UEFI secure boot enabled, and the image failed to
// authenticate. For compatibility reasons, we fall back to the legacy
// loader in this case. Since the image has been loaded, we need to unload
// it before proceeding
// Since the image has been loaded, we need to unload it before proceeding
// to the EFI_ACCESS_DENIED case below.
//
gBS->UnloadImage (KernelImageHandle);
//
// Fall through
//
case EFI_ACCESS_DENIED:
//
// We are running with UEFI secure boot enabled, and the image failed to
// authenticate. For compatibility reasons, we fall back to the legacy
// loader in this case.
//
// Fall through
//
case EFI_UNSUPPORTED:
//
// The image is not natively supported or cross-type supported. Let's try