Re: [PATCH v9 1/1] efi_loader: add PE/COFF image measurement

On Thu, 27 May 2021 at 01:28, Alex G. mr.nuke.me@gmail.com wrote:

On 5/25/21 10:09 PM, Masahisa Kojima wrote:

...

"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.

Acked-by: Ilias Apalodimas ilias.apalodimas@linaro.org Tested-by: Ilias Apalodimas ilias.apalodimas@linaro.org Signed-off-by: Masahisa Kojima masahisa.kojima@linaro.org

---

Changes in v9:

• use original return code from __get_active_pcr_banks()
• return EFI_UNSUPPORTED instead of EFI_INVALID_PARAMETER if efi_image_parse() fails, it complies with TCG spec
• remove **new_efi parameter from efi_prepare_aligned_image() to improve the readability

(no changes since v7)

Changes in v7:

• include hash-checksum.h instead of rsa.h
• select HASH_CALCULATE in Kconfig, not to update lib/Makefile

I want to remove HASH_CALCULATE for Kconfig for reasons outlined in (1):

(1) https://patchwork.ozlabs.org/project/uboot/patch/20210524192857.1486696-2-mr...

The root of the problem is that selecting SHA_xxx should compile and link the hash_calculate() symbol, and this would make the existing kconfig correct. Unfortunately, the selection doesn't happen automatically because the SHA code isn't too well organized.

To solve your problem, I would prefer that you take the series in (1) -- there's a second patch after it -- and use "select HASH" here. You're asking "What's the difference ?". The difference is that "HASH" is an existing Kconfig symbol, so we don't need to also add "HASH_CALULATE".

As I replied to your series, I agree with your modification.

Thanks, Masahisa Kojima

Alex

...

• rebased the base code

Changes in v6:

• update lib/Makefile to add hash-checksum.c as a compilation target

(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/Kconfig | 1 + lib/efi_loader/efi_image_loader.c | 62 ++++++--- lib/efi_loader/efi_tcg2.c | 207 ++++++++++++++++++++++++++++-- 6 files changed, 277 insertions(+), 26 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 522696d635..0a9c82a257 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,

@@ -886,6 +890,8 @@ bool efi_secure_boot_enabled(void);

bool efi_capsule_auth_enabled(void);

+void *efi_prepare_aligned_image(void *efi, u64 *efi_size);

• 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 7de7d6a57d..247b386967 100644 --- a/include/tpm-v2.h +++ b/include/tpm-v2.h @@ -70,6 +70,24 @@ struct udevice; #define EV_TABLE_OF_DEVICES ((u32)0x0000000B) #define EV_COMPACT_HASH ((u32)0x0000000C)

+/*

• • 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/Kconfig b/lib/efi_loader/Kconfig index 98845b8ba3..0e6200fa25 100644 --- a/lib/efi_loader/Kconfig +++ b/lib/efi_loader/Kconfig @@ -309,6 +309,7 @@ config EFI_TCG2_PROTOCOL select SHA512_ALGO select SHA384 select SHA512

• select HASH_CALCULATE
  help
    Provide a EFI_TCG2_PROTOCOL implementation using the TPM hardware
    of the platform.
  

diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index fe1ee198e2..bcd57f7fcc 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -302,6 +302,38 @@ 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
• • If @efi is not 8-byte aligned, this function newly allocates
• • the image buffer.
• • Return: valid pointer to a image, return NULL if allocation fails.
• */

+void *efi_prepare_aligned_image(void *efi, u64 *efi_size) +{

• size_t new_efi_size;
  

• void *new_efi;
  

• /*
  

•  * 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);
  

•         new_efi = calloc(new_efi_size, 1);
  

•         if (!new_efi)
  

•                 return NULL;
  

•         memcpy(new_efi, efi, *efi_size);
  

•         *efi_size = new_efi_size;
  

•         return new_efi;
  

• } else {
  

•         return efi;
  

• }
  

+}

• /**
  • efi_image_parse() - parse a PE image
  • @efi: Pointer to image

@@ -561,7 +593,7 @@ 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);
  

@@ -569,21 +601,11 @@ 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;
  

• }
  

• new_efi = efi_prepare_aligned_image(efi, (u64 *)&efi_size);
  

• if (!new_efi)
  

•         return false;
  
  

• if (!efi_image_parse(efi, efi_size, &regs, &wincerts,
  

• if (!efi_image_parse(new_efi, efi_size, &regs, &wincerts,
                       &wincerts_len)) {
          EFI_PRINT("Parsing PE executable image failed\n");
          goto err;
  

@@ -725,7 +747,8 @@ err: efi_sigstore_free(dbx); pkcs7_free_message(msg); free(regs);

• free(new_efi);
  

• if (new_efi != efi)
  

•         free(new_efi);
  
  EFI_PRINT("%s: Exit, %d\n", __func__, ret);
  return ret;
  

@@ -891,6 +914,13 @@ 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 39074f7547..3dd417aa27 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/hash-checksum.h> #include <u-boot/sha1.h> #include <u-boot/sha256.h> #include <u-boot/sha512.h> @@ -707,6 +709,183 @@ 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;
  

• new_efi = efi_prepare_aligned_image(efi, &efi_size);
  

• if (!new_efi)
  

•         return EFI_OUT_OF_RESOURCES;
  

• if (!efi_image_parse(new_efi, efi_size, &regs, &wincerts,
  

•                      &wincerts_len)) {
  

•         log_err("Parsing PE executable image failed\n");
  

•         ret = EFI_UNSUPPORTED;
  

•         goto out;
  

• }
  

• ret = __get_active_pcr_banks(&active);
  

• if (ret != EFI_SUCCESS) {
  

•         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:

• if (new_efi != efi)
  

•         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_hash_pe_image((void *)data_to_hash, data_to_hash_len,
  

•                                  &digest_list);
  

• } else {
  

•         ret = tcg2_create_digest((u8 *)(uintptr_t)data_to_hash,
  

•                                  data_to_hash_len, &digest_list);
  

• }
  
  

• ret = tcg2_create_digest((u8 *)(uintptr_t)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;