efi_loader: add signature verification functions

In this commit, implemented are a couple of helper functions which will be
used to materialize variable authentication as well as image authentication
in later patches.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

2 files changed, 159 insertions, 0 deletions

diff --git a/include/efi_api.h b/include/efi_api.h
index 1c40ffc4f5..77d6bf2660 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -18,6 +18,7 @@
 
 #include <efi.h>
 #include <charset.h>
+#include <pe.h>
 
 #ifdef CONFIG_EFI_LOADER
 #include <asm/setjmp.h>
@@ -329,6 +330,10 @@ struct efi_runtime_services {
 	EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \
 		 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c)
 
+#define EFI_IMAGE_SECURITY_DATABASE_GUID \
+	EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \
+		 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
+
 #define EFI_FDT_GUID \
 	EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \
 		 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0)
@@ -1682,4 +1687,86 @@ struct efi_load_file_protocol {
 #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000
 #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000
 
+/* Certificate types in signature database */
+#define EFI_CERT_SHA256_GUID \
+	EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \
+		 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
+#define EFI_CERT_RSA2048_GUID \
+	EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \
+		 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6)
+#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)
+#define EFI_CERT_TYPE_PKCS7_GUID \
+	EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \
+		 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7)
+
+/**
+ * win_certificate_uefi_guid - A certificate that encapsulates
+ * a GUID-specific signature
+ *
+ * @hdr:	Windows certificate header
+ * @cert_type:	Certificate type
+ * @cert_data:	Certificate data
+ */
+struct win_certificate_uefi_guid {
+	WIN_CERTIFICATE	hdr;
+	efi_guid_t	cert_type;
+	u8		cert_data[];
+} __attribute__((__packed__));
+
+/**
+ * efi_variable_authentication_2 - A time-based authentication method
+ * descriptor
+ *
+ * This structure describes an authentication information for
+ * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
+ * and should be included as part of a variable's value.
+ * Only EFI_CERT_TYPE_PKCS7_GUID is accepted.
+ *
+ * @time_stamp:	Descriptor's time stamp
+ * @auth_info:	Authentication info
+ */
+struct efi_variable_authentication_2 {
+	struct efi_time			 time_stamp;
+	struct win_certificate_uefi_guid auth_info;
+} __attribute__((__packed__));
+
+/**
+ * efi_signature_data - A format of signature
+ *
+ * This structure describes a single signature in signature database.
+ *
+ * @signature_owner:	Signature owner
+ * @signature_data:	Signature data
+ */
+struct efi_signature_data {
+	efi_guid_t	signature_owner;
+	u8		signature_data[];
+} __attribute__((__packed__));
+
+/**
+ * efi_signature_list - A format of signature database
+ *
+ * This structure describes a list of signatures with the same type.
+ * An authenticated variable's value is a concatenation of one or more
+ * efi_signature_list's.
+ *
+ * @signature_type:		Signature type
+ * @signature_list_size:	Size of signature list
+ * @signature_header_size:	Size of signature header
+ * @signature_size:		Size of signature
+ */
+struct efi_signature_list {
+	efi_guid_t	signature_type;
+	u32		signature_list_size;
+	u32		signature_header_size;
+	u32		signature_size;
+/*	u8		signature_header[signature_header_size]; */
+/*	struct efi_signature_data signatures[...][signature_size]; */
+} __attribute__((__packed__));
+
 #endif
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 3f2792892f..8cf85d2fb7 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src)
 #if CONFIG_IS_ENABLED(EFI_LOADER)
 
 #include <linux/list.h>
+#include <linux/oid_registry.h>
 
 /* Maximum number of configuration tables */
 #define EFI_MAX_CONFIGURATION_TABLES 16
@@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol;
 extern const efi_guid_t efi_guid_hii_config_access_protocol;
 extern const efi_guid_t efi_guid_hii_database_protocol;
 extern const efi_guid_t efi_guid_hii_string_protocol;
+/* GUIDs for authentication */
+extern const efi_guid_t efi_guid_image_security_database;
+extern const efi_guid_t efi_guid_sha256;
+extern const efi_guid_t efi_guid_cert_x509;
+extern const efi_guid_t efi_guid_cert_x509_sha256;
 
 /* GUID of RNG protocol */
 extern const efi_guid_t efi_guid_rng_protocol;
@@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data);
 unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data);
 efi_status_t efi_bootmgr_load(efi_handle_t *handle);
 
+#ifdef CONFIG_EFI_SECURE_BOOT
+#include <image.h>
+
+/**
+ * efi_image_regions - A list of memory regions
+ *
+ * @max:	Maximum number of regions
+ * @num:	Number of regions
+ * @reg:	array of regions
+ */
+struct efi_image_regions {
+	int			max;
+	int			num;
+	struct image_region	reg[];
+};
+
+/**
+ * efi_sig_data - A decoded data of struct efi_signature_data
+ *
+ * This structure represents an internal form of signature in
+ * signature database. A listed list may represent a signature list.
+ *
+ * @next:	Pointer to next entry
+ * @onwer:	Signature owner
+ * @data:	Pointer to signature data
+ * @size:	Size of signature data
+ */
+struct efi_sig_data {
+	struct efi_sig_data *next;
+	efi_guid_t owner;
+	void *data;
+	size_t size;
+};
+
+/**
+ * efi_signature_store - A decoded data of signature database
+ *
+ * This structure represents an internal form of signature database.
+ *
+ * @next:		Pointer to next entry
+ * @sig_type:		Signature type
+ * @sig_data_list:	Pointer to signature list
+ */
+struct efi_signature_store {
+	struct efi_signature_store *next;
+	efi_guid_t sig_type;
+	struct efi_sig_data *sig_data_list;
+};
+
+struct x509_certificate;
+struct pkcs7_message;
+
+bool efi_signature_verify_cert(struct x509_certificate *cert,
+			       struct efi_signature_store *dbx);
+bool efi_signature_verify_signers(struct pkcs7_message *msg,
+				  struct efi_signature_store *dbx);
+bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,
+				     struct pkcs7_message *msg,
+				  struct efi_signature_store *db,
+				  struct x509_certificate **cert);
+
+efi_status_t efi_image_region_add(struct efi_image_regions *regs,
+				  const void *start, const void *end,
+				  int nocheck);
+#endif /* CONFIG_EFI_SECURE_BOOT */
+
 #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
 
 /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */