[v3,2/2] efi_loader: add PE/COFF image measurement

Message ID 20210428121945.12586-3-masahisa.kojima@linaro.org
State Superseded
Headers show
Series
  • PE/COFF measurement support
Related show

Commit Message

Masahisa Kojima April 28, 2021, 12:19 p.m.
"TCG PC Client Platform Firmware Profile Specification"
requires to measure every attempt to load and execute
a OS Loader(a UEFI application) into PCR[4].
This commit adds the PE/COFF image measurement, extends PCR,
and appends measurement into Event Log.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>

---

(no changes since v2)

Changes in v2:
- Remove duplicate <efi.h> include
- Remove unnecessary __packed attribute
- Add all EV_EFI_* event definition
- Create common function to prepare 8-byte aligned image
- Add measurement for EV_EFI_BOOT_SERVICES_DRIVER and
  EV_EFI_RUNTIME_SERVICES_DRIVER
- Use efi_search_protocol() to get device_path
- Add function comment


 include/efi_loader.h              |   6 +
 include/efi_tcg2.h                |   9 ++
 include/tpm-v2.h                  |  18 +++
 lib/efi_loader/efi_image_loader.c |  59 +++++++--
 lib/efi_loader/efi_tcg2.c         | 207 ++++++++++++++++++++++++++++--
 5 files changed, 275 insertions(+), 24 deletions(-)

-- 
2.17.1

Patch

diff --git a/include/efi_loader.h b/include/efi_loader.h
index de1a496a97..9f2854a255 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -426,6 +426,10 @@  efi_status_t efi_disk_register(void);
 efi_status_t efi_rng_register(void);
 /* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
 efi_status_t efi_tcg2_register(void);
+/* measure the pe-coff image, extend PCR and add Event Log */
+efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
+				   struct efi_loaded_image_obj *handle,
+				   struct efi_loaded_image *loaded_image_info);
 /* Create handles and protocols for the partitions of a block device */
 int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
 			       const char *if_typename, int diskid,
@@ -847,6 +851,8 @@  bool efi_secure_boot_enabled(void);
 
 bool efi_capsule_auth_enabled(void);
 
+void *efi_prepare_aligned_image(void *efi, u64 *efi_size, void **new_efi);
+
 bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 		     WIN_CERTIFICATE **auth, size_t *auth_len);
 
diff --git a/include/efi_tcg2.h b/include/efi_tcg2.h
index 40e241ce31..bcfb98168a 100644
--- a/include/efi_tcg2.h
+++ b/include/efi_tcg2.h
@@ -9,6 +9,7 @@ 
 #if !defined _EFI_TCG2_PROTOCOL_H_
 #define _EFI_TCG2_PROTOCOL_H_
 
+#include <efi_api.h>
 #include <tpm-v2.h>
 
 #define EFI_TCG2_PROTOCOL_GUID \
@@ -53,6 +54,14 @@  struct efi_tcg2_event {
 	u8 event[];
 } __packed;
 
+struct uefi_image_load_event {
+	efi_physical_addr_t image_location_in_memory;
+	u64 image_length_in_memory;
+	u64 image_link_time_address;
+	u64 length_of_device_path;
+	struct efi_device_path device_path[];
+};
+
 struct efi_tcg2_boot_service_capability {
 	u8 size;
 	struct efi_tcg2_version structure_version;
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index df67a196cf..6e812c017c 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -62,6 +62,24 @@  struct udevice;
 #define EV_CPU_MICROCODE	((u32)0x00000009)
 #define EV_TABLE_OF_DEVICES	((u32)0x0000000B)
 
+/*
+ * event types, cf.
+ * "TCG PC Client Platform Firmware Profile Specification", Family "2.0"
+ * rev 1.04, June 3, 2019
+ */
+#define EV_EFI_EVENT_BASE			((u32)0x80000000)
+#define EV_EFI_VARIABLE_DRIVER_CONFIG		((u32)0x80000001)
+#define EV_EFI_VARIABLE_BOOT			((u32)0x80000002)
+#define EV_EFI_BOOT_SERVICES_APPLICATION	((u32)0x80000003)
+#define EV_EFI_BOOT_SERVICES_DRIVER		((u32)0x80000004)
+#define EV_EFI_RUNTIME_SERVICES_DRIVER		((u32)0x80000005)
+#define EV_EFI_GPT_EVENT			((u32)0x80000006)
+#define EV_EFI_ACTION				((u32)0x80000007)
+#define EV_EFI_PLATFORM_FIRMWARE_BLOB		((u32)0x80000008)
+#define EV_EFI_HANDOFF_TABLES			((u32)0x80000009)
+#define EV_EFI_HCRTM_EVENT			((u32)0x80000010)
+#define EV_EFI_VARIABLE_AUTHORITY		((u32)0x800000E0)
+
 /* TPMS_TAGGED_PROPERTY Structure */
 struct tpms_tagged_property {
 	u32 property;
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index b8a790bcb9..cc548e1b88 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -302,6 +302,40 @@  static int cmp_pe_section(const void *arg1, const void *arg2)
 		return 1;
 }
 
+/**
+ * efi_prepare_aligned_image() - prepare 8-byte aligned image
+ * @efi:		pointer to the EFI binary
+ * @efi_size:		size of @efi binary
+ * @new_efi:		pointer to the newly allocated image
+ *
+ * If @efi is not 8-byte aligned, this function newly allocates
+ * the image buffer and updates @efi_size.
+ *
+ * Return:	valid pointer to a image, return NULL if allocation fails.
+ */
+void *efi_prepare_aligned_image(void *efi, u64 *efi_size, void **new_efi)
+{
+	size_t new_efi_size;
+	void *p;
+
+	/*
+	 * Size must be 8-byte aligned and the trailing bytes must be
+	 * zero'ed. Otherwise hash value may be incorrect.
+	 */
+	if (!IS_ALIGNED(*efi_size, 8)) {
+		new_efi_size = ALIGN(*efi_size, 8);
+		p = calloc(new_efi_size, 1);
+		if (!p)
+			return NULL;
+		memcpy(p, efi, *efi_size);
+		*efi_size = new_efi_size;
+		*new_efi = p;
+		return p;
+	} else {
+		return efi;
+	}
+}
+
 /**
  * efi_image_parse() - parse a PE image
  * @efi:	Pointer to image
@@ -560,7 +594,7 @@  static bool efi_image_authenticate(void *efi, size_t efi_size)
 	struct efi_signature_store *db = NULL, *dbx = NULL;
 	void *new_efi = NULL;
 	u8 *auth, *wincerts_end;
-	size_t new_efi_size, auth_size;
+	size_t auth_size;
 	bool ret = false;
 
 	EFI_PRINT("%s: Enter, %d\n", __func__, ret);
@@ -571,19 +605,9 @@  static bool efi_image_authenticate(void *efi, size_t efi_size)
 	if (!efi_secure_boot_enabled())
 		return true;
 
-	/*
-	 * Size must be 8-byte aligned and the trailing bytes must be
-	 * zero'ed. Otherwise hash value may be incorrect.
-	 */
-	if (efi_size & 0x7) {
-		new_efi_size = (efi_size + 0x7) & ~0x7ULL;
-		new_efi = calloc(new_efi_size, 1);
-		if (!new_efi)
-			return false;
-		memcpy(new_efi, efi, efi_size);
-		efi = new_efi;
-		efi_size = new_efi_size;
-	}
+	efi = efi_prepare_aligned_image(efi, (u64 *)&efi_size, &new_efi);
+	if (!efi)
+		return false;
 
 	if (!efi_image_parse(efi, efi_size, &regs, &wincerts,
 			     &wincerts_len)) {
@@ -886,6 +910,13 @@  efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
 		goto err;
 	}
 
+#if CONFIG_IS_ENABLED(EFI_TCG2_PROTOCOL)
+	/* Measure an PE/COFF image */
+	if (tcg2_measure_pe_image(efi, efi_size, handle,
+				  loaded_image_info))
+		log_err("PE image measurement failed\n");
+#endif
+
 	/* Copy PE headers */
 	memcpy(efi_reloc, efi,
 	       sizeof(*dos)
diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
index 94e8f22bbb..7ad9cb2b89 100644
--- a/lib/efi_loader/efi_tcg2.c
+++ b/lib/efi_loader/efi_tcg2.c
@@ -13,8 +13,10 @@ 
 #include <efi_loader.h>
 #include <efi_tcg2.h>
 #include <log.h>
+#include <malloc.h>
 #include <version.h>
 #include <tpm-v2.h>
+#include <u-boot/rsa.h>
 #include <u-boot/sha1.h>
 #include <u-boot/sha256.h>
 #include <u-boot/sha512.h>
@@ -706,6 +708,183 @@  out:
 	return EFI_EXIT(ret);
 }
 
+/**
+ * tcg2_hash_pe_image() - calculate PE/COFF image hash
+ *
+ * @efi:		pointer to the EFI binary
+ * @efi_size:		size of @efi binary
+ * @digest_list:	list of digest algorithms to extend
+ *
+ * Return:	status code
+ */
+static efi_status_t tcg2_hash_pe_image(void *efi, u64 efi_size,
+				       struct tpml_digest_values *digest_list)
+{
+	WIN_CERTIFICATE *wincerts = NULL;
+	size_t wincerts_len;
+	struct efi_image_regions *regs = NULL;
+	void *new_efi = NULL;
+	u8 hash[TPM2_SHA512_DIGEST_SIZE];
+	efi_status_t ret;
+	u32 active;
+	int i;
+
+	efi = efi_prepare_aligned_image(efi, &efi_size, &new_efi);
+	if (!efi)
+		return EFI_OUT_OF_RESOURCES;
+
+	if (!efi_image_parse(efi, efi_size, &regs, &wincerts,
+			     &wincerts_len)) {
+		log_err("Parsing PE executable image failed\n");
+		ret = EFI_INVALID_PARAMETER;
+		goto out;
+	}
+
+	ret = __get_active_pcr_banks(&active);
+	if (ret != EFI_SUCCESS) {
+		ret = EFI_DEVICE_ERROR;
+		goto out;
+	}
+
+	digest_list->count = 0;
+	for (i = 0; i < MAX_HASH_COUNT; i++) {
+		u16 hash_alg = hash_algo_list[i].hash_alg;
+
+		if (!(active & alg_to_mask(hash_alg)))
+			continue;
+		switch (hash_alg) {
+		case TPM2_ALG_SHA1:
+			hash_calculate("sha1", regs->reg, regs->num, hash);
+			break;
+		case TPM2_ALG_SHA256:
+			hash_calculate("sha256", regs->reg, regs->num, hash);
+			break;
+		case TPM2_ALG_SHA384:
+			hash_calculate("sha384", regs->reg, regs->num, hash);
+			break;
+		case TPM2_ALG_SHA512:
+			hash_calculate("sha512", regs->reg, regs->num, hash);
+			break;
+		default:
+			EFI_PRINT("Unsupported algorithm %x\n", hash_alg);
+			return EFI_INVALID_PARAMETER;
+		}
+		digest_list->digests[i].hash_alg = hash_alg;
+		memcpy(&digest_list->digests[i].digest, hash, (u32)alg_to_len(hash_alg));
+		digest_list->count++;
+	}
+
+out:
+	free(new_efi);
+	free(regs);
+
+	return ret;
+}
+
+/**
+ * tcg2_measure_pe_image() - measure PE/COFF image
+ *
+ * @efi:		pointer to the EFI binary
+ * @efi_size:		size of @efi binary
+ * @handle:		loaded image handle
+ * @loaded_image:	loaded image protocol
+ *
+ * Return:	status code
+ */
+efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
+				   struct efi_loaded_image_obj *handle,
+				   struct efi_loaded_image *loaded_image)
+{
+	struct tpml_digest_values digest_list;
+	efi_status_t ret;
+	struct udevice *dev;
+	u32 pcr_index, event_type, event_size;
+	struct uefi_image_load_event *image_load_event;
+	struct efi_device_path *device_path;
+	u32 device_path_length;
+	IMAGE_DOS_HEADER *dos;
+	IMAGE_NT_HEADERS32 *nt;
+	struct efi_handler *handler;
+
+	ret = platform_get_tpm2_device(&dev);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	switch (handle->image_type) {
+	case IMAGE_SUBSYSTEM_EFI_APPLICATION:
+		pcr_index = 4;
+		event_type = EV_EFI_BOOT_SERVICES_APPLICATION;
+		break;
+	case IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
+		pcr_index = 2;
+		event_type = EV_EFI_BOOT_SERVICES_DRIVER;
+		break;
+	case IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
+		pcr_index = 2;
+		event_type = EV_EFI_RUNTIME_SERVICES_DRIVER;
+		break;
+	default:
+		return EFI_UNSUPPORTED;
+	}
+
+	ret = tcg2_hash_pe_image(efi, efi_size, &digest_list);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	ret = EFI_CALL(efi_search_protocol(&handle->header,
+					   &efi_guid_loaded_image_device_path,
+					   &handler));
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	device_path = EFI_CALL(handler->protocol_interface);
+	device_path_length = efi_dp_size(device_path);
+	if (device_path_length > 0) {
+		/* add end node size */
+		device_path_length += sizeof(struct efi_device_path);
+	}
+	event_size = sizeof(struct uefi_image_load_event) + device_path_length;
+	image_load_event = (struct uefi_image_load_event *)malloc(event_size);
+	if (!image_load_event)
+		return EFI_OUT_OF_RESOURCES;
+
+	image_load_event->image_location_in_memory = (efi_physical_addr_t)efi;
+	image_load_event->image_length_in_memory = efi_size;
+	image_load_event->length_of_device_path = device_path_length;
+
+	dos = (IMAGE_DOS_HEADER *)efi;
+	nt = (IMAGE_NT_HEADERS32 *)(efi + dos->e_lfanew);
+	if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
+		IMAGE_NT_HEADERS64 *nt64 = (IMAGE_NT_HEADERS64 *)nt;
+
+		image_load_event->image_link_time_address =
+				nt64->OptionalHeader.ImageBase;
+	} else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
+		image_load_event->image_link_time_address =
+				nt->OptionalHeader.ImageBase;
+	} else {
+		ret = EFI_INVALID_PARAMETER;
+		goto out;
+	}
+
+	if (device_path_length > 0) {
+		memcpy(image_load_event->device_path, device_path,
+		       device_path_length);
+	}
+
+	ret = tcg2_agile_log_append(pcr_index, event_type, &digest_list,
+				    event_size, (u8 *)image_load_event);
+
+out:
+	free(image_load_event);
+
+	return ret;
+}
+
 /**
  * efi_tcg2_hash_log_extend_event() - extend and optionally log events
  *
@@ -758,24 +937,32 @@  efi_tcg2_hash_log_extend_event(struct efi_tcg2_protocol *this, u64 flags,
 	/*
 	 * if PE_COFF_IMAGE is set we need to make sure the image is not
 	 * corrupted, verify it and hash the PE/COFF image in accordance with
-	 * the  procedure  specified  in  "Calculating  the  PE  Image  Hash"
-	 * section  of the "Windows Authenticode Portable Executable Signature
+	 * the procedure specified in "Calculating the PE Image Hash"
+	 * section of the "Windows Authenticode Portable Executable Signature
 	 * Format"
-	 * Not supported for now
 	 */
 	if (flags & PE_COFF_IMAGE) {
-		ret = EFI_UNSUPPORTED;
-		goto out;
-	}
+		IMAGE_NT_HEADERS32 *nt;
 
-	pcr_index = efi_tcg_event->header.pcr_index;
-	event_type = efi_tcg_event->header.event_type;
+		ret = efi_check_pe((void *)data_to_hash, data_to_hash_len,
+				   (void **)&nt);
+		if (ret != EFI_SUCCESS) {
+			log_err("Not a valid PE-COFF file\n");
+			goto out;
+		}
 
-	ret = tcg2_create_digest((u8 *)data_to_hash, data_to_hash_len,
-				 &digest_list);
+		ret = tcg2_hash_pe_image((void *)data_to_hash, data_to_hash_len,
+					 &digest_list);
+	} else {
+		ret = tcg2_create_digest((u8 *)data_to_hash, data_to_hash_len,
+					 &digest_list);
+	}
 	if (ret != EFI_SUCCESS)
 		goto out;
 
+	pcr_index = efi_tcg_event->header.pcr_index;
+	event_type = efi_tcg_event->header.event_type;
+
 	ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
 	if (ret != EFI_SUCCESS)
 		goto out;