[PATCH v2 2/2] efi_loader: add PE/COFF image measurement
Masahisa Kojima
masahisa.kojima at linaro.org
Tue Apr 27 15:08:11 CEST 2021
"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 at linaro.org>
---
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(-)
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, ®s, &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, ®s, &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;
--
2.17.1
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