efi: Add EFI signature data types

Add the data types that are used for containing hashes, keys and
certificates for cryptographic verification along with their corresponding
type GUIDs.

Signed-off-by: David Howells <[e-mail]>
Acked-by: Nayna Jain <[e-mail]>
Acked-by: Serge Hallyn <[e-mail]>
Reviewed-by: James Morris <[e-mail]>
Signed-off-by: Mimi Zohar <[e-mail]>

include/linux/efi.h

···
 #define EFI_IMAGE_SECURITY_DATABASE_GUID	EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596,  0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
 #define EFI_SHIM_LOCK_GUID			EFI_GUID(0x605dab50, 0xe046, 0x4300,  0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
 
+#define EFI_CERT_SHA256_GUID			EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
+#define EFI_CERT_X509_GUID			EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72)
+#define EFI_CERT_X509_SHA256_GUID		EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed)
+
 /*
  * This GUID is used to pass to the kernel proper the struct screen_info
  * structure that was populated by the stub based on the GOP protocol instance
···
 	u32 reserved;
 	efi_memory_desc_t entry[0];
 } efi_memory_attributes_table_t;
+
+typedef struct {
+	efi_guid_t signature_owner;
+	u8 signature_data[];
+} efi_signature_data_t;
+
+typedef struct {
+	efi_guid_t signature_type;
+	u32 signature_list_size;
+	u32 signature_header_size;
+	u32 signature_size;
+	u8 signature_header[];
+	/* efi_signature_data_t signatures[][] */
+} efi_signature_list_t;
+
+typedef u8 efi_sha256_hash_t[32];
+
+typedef struct {
+	efi_sha256_hash_t to_be_signed_hash;
+	efi_time_t time_of_revocation;
+} efi_cert_x509_sha256_t;
 
 /*
  * All runtime access to EFI goes through this structure: