x86/EFI: add code interfacing with the secure boot shim

... to validate the kernel image (which is required to be in PE
format, as is e.g. the case for the Linux bzImage when built with
CONFIG_EFI_STUB).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

diff --git a/xen/arch/x86/efi/boot.c b/xen/arch/x86/efi/boot.c
index 851057e563abf0d7a65d70b50f6cb19833b6a01c..10c698c090e1e24ac36960bae2d120049e19739e 100644 (file)
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -24,6 +24,18 @@
 #include <asm/msr.h>
 #include <asm/processor.h>
 
+#define SHIM_LOCK_PROTOCOL_GUID \
+  { 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} }
+
+typedef EFI_STATUS
+(/* _not_ EFIAPI */ *EFI_SHIM_LOCK_VERIFY) (
+    IN VOID *Buffer,
+    IN UINT32 Size);
+
+typedef struct {
+    EFI_SHIM_LOCK_VERIFY Verify;
+} EFI_SHIM_LOCK_PROTOCOL;
+
 extern char start[];
 extern u32 cpuid_ext_features;
 
@@ -640,12 +652,14 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     static EFI_GUID __initdata gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
     static EFI_GUID __initdata bio_guid = BLOCK_IO_PROTOCOL;
     static EFI_GUID __initdata devp_guid = DEVICE_PATH_PROTOCOL;
+    static EFI_GUID __initdata shim_lock_guid = SHIM_LOCK_PROTOCOL_GUID;
     EFI_LOADED_IMAGE *loaded_image;
     EFI_STATUS status;
     unsigned int i, argc;
     CHAR16 **argv, *file_name, *cfg_file_name = NULL;
     UINTN cols, rows, depth, size, map_key, info_size, gop_mode = ~0;
     EFI_HANDLE *handles = NULL;
+    EFI_SHIM_LOCK_PROTOCOL *shim_lock;
     EFI_GRAPHICS_OUTPUT_PROTOCOL *gop = NULL;
     EFI_GRAPHICS_OUTPUT_MODE_INFORMATION *mode_info;
     EFI_FILE_HANDLE dir_handle;
@@ -835,6 +849,11 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     read_file(dir_handle, s2w(&name), &kernel);
     efi_bs->FreePool(name.w);
 
+    if ( !EFI_ERROR(efi_bs->LocateProtocol(&shim_lock_guid, NULL,
+                    (void **)&shim_lock)) &&
+         shim_lock->Verify(kernel.ptr, kernel.size) != EFI_SUCCESS )
+        blexit(L"Dom0 kernel image could not be verified\r\n");
+
     name.s = get_value(&cfg, section.s, "ramdisk");
     if ( name.s )
     {