Re: [PATCH v2] efi_loader: Add a locality event on the eventlog

Responding to myself here, but after re-reading the spec, I realized this is only required, if the startup locality was set to '3'. So Heinrich please ignore this for now, I'll repost it once we have a way to read the startup locality properly

Cheers /Ilias

On Wed, 24 Mar 2021 at 09:43, Ilias Apalodimas ilias.apalodimas@linaro.org wrote:

We are currently not adding any events on the eventlog apart from the SpecID event. The locality event is mandatory and must be logged before extending PCR[0].

The spec description is "The Startup Locality event should be placed in the log before any event which extends PCR[0]. This allows software which needs to parse the TCG Event Log to initialize its internal PCR[0] state correctly".

So let's add a locality even during the EventLog creation, right after our SpecID event.

Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org

changes since v1:

• v1 was missing the required headers changes
• exit on tcg2_create_digest() failure

include/efi_tcg2.h | 13 ++++++++++ lib/efi_loader/efi_tcg2.c | 52 +++++++++++++++++++++++++++++---------- 2 files changed, 52 insertions(+), 13 deletions(-)

diff --git a/include/efi_tcg2.h b/include/efi_tcg2.h index 40e241ce315c..eac76774d7ff 100644 --- a/include/efi_tcg2.h +++ b/include/efi_tcg2.h @@ -72,6 +72,7 @@ struct efi_tcg2_boot_service_capability { offsetof(struct efi_tcg2_boot_service_capability, number_of_pcr_banks)

#define TCG_EFI_SPEC_ID_EVENT_SIGNATURE_03 "Spec ID Event03" +#define TCG_EFI_STARTUP_LOCALITY_SIGNATURE "StartupLocality" #define TCG_EFI_SPEC_ID_EVENT_SPEC_VERSION_MAJOR_TPM2 2 #define TCG_EFI_SPEC_ID_EVENT_SPEC_VERSION_MINOR_TPM2 0 #define TCG_EFI_SPEC_ID_EVENT_SPEC_VERSION_ERRATA_TPM2 2 @@ -120,6 +121,18 @@ struct tcg_efi_spec_id_event { u8 vendor_info[]; } __packed;

+/**

• • struct tdTCG_EfiStartupLocalityEvent
• • @signature: The NUL-terminated ASCII string "StartupLocality"
• • @startup_locality: The Locality Indicator which sent the TPM2_Startup

• •                 command
    

• */

+struct tcg_efi_startup_locality_event {

•   u8 signature[16];
  

•   u8 startup_locality;
  

+} __packed;

/**

• struct tdEFI_TCG2_FINAL_EVENTS_TABLE
• @version: version number for this structure

diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c index 797d6eb134f6..31c80b21d8b5 100644 --- a/lib/efi_loader/efi_tcg2.c +++ b/lib/efi_loader/efi_tcg2.c @@ -513,7 +513,7 @@ static efi_status_t tcg2_create_digest(const u8 *input, u32 length, sha1_context ctx; sha256_context ctx_256; sha512_context ctx_512;

•   u8 final[TPM2_ALG_SHA512];
  

•   u8 final[TPM2_ALG_SHA512] = { 0 };
    efi_status_t ret;
    u32 active;
    int i;
  

@@ -530,27 +530,35 @@ static efi_status_t tcg2_create_digest(const u8 *input, u32 length, continue; switch (hash_alg) { case TPM2_ALG_SHA1:

•                   sha1_starts(&ctx);
  

•                   sha1_update(&ctx, input, length);
  

•                   sha1_finish(&ctx, final);
  

•                   if (input) {
  

•                           sha1_starts(&ctx);
  

•                           sha1_update(&ctx, input, length);
  

•                           sha1_finish(&ctx, final);
  

•                   }
                    digest_list->count++;
                    break;
            case TPM2_ALG_SHA256:
  

•                   sha256_starts(&ctx_256);
  

•                   sha256_update(&ctx_256, input, length);
  

•                   sha256_finish(&ctx_256, final);
  

•                   if (input) {
  

•                           sha256_starts(&ctx_256);
  

•                           sha256_update(&ctx_256, input, length);
  

•                           sha256_finish(&ctx_256, final);
  

•                   }
                    digest_list->count++;
                    break;
            case TPM2_ALG_SHA384:
  

•                   sha384_starts(&ctx_512);
  

•                   sha384_update(&ctx_512, input, length);
  

•                   sha384_finish(&ctx_512, final);
  

•                   if (input) {
  

•                           sha384_starts(&ctx_512);
  

•                           sha384_update(&ctx_512, input, length);
  

•                           sha384_finish(&ctx_512, final);
  

•                   }
                    digest_list->count++;
                    break;
            case TPM2_ALG_SHA512:
  

•                   sha512_starts(&ctx_512);
  

•                   sha512_update(&ctx_512, input, length);
  

•                   sha512_finish(&ctx_512, final);
  

•                   if (input) {
  

•                           sha512_starts(&ctx_512);
  

•                           sha512_update(&ctx_512, input, length);
  

•                           sha512_finish(&ctx_512, final);
  

•                   }
                    digest_list->count++;
                    break;
            default:
  

@@ -1004,6 +1012,8 @@ static efi_status_t efi_init_event_log(void) struct udevice *dev; size_t spec_event_size; efi_status_t ret;

•   struct tcg_efi_startup_locality_event locality_event;
  

•   struct tpml_digest_values digest_list;
  
    ret = platform_get_tpm2_device(&dev);
    if (ret != EFI_SUCCESS)
  

@@ -1040,6 +1050,22 @@ static efi_status_t efi_init_event_log(void) event_log.pos = spec_event_size + sizeof(*event_header); event_log.last_event_size = event_log.pos;

•   /* Add a locality event before PCR[0] changes */
  

•   memcpy(locality_event.signature, TCG_EFI_STARTUP_LOCALITY_SIGNATURE,
  

•          sizeof(locality_event.signature));
  

•   /*
  

•    * Locality 0 is designated as the default Locality. This is usually
  

•    * the platform’s boot firmware, OS and applications.
  

•    */
  

•   locality_event.startup_locality = 0;
  

•   ret = tcg2_create_digest(NULL, 0, &digest_list);
  

•   if (ret != EFI_SUCCESS)
  

•           goto out;
  

•   ret = tcg2_agile_log_append(0, EV_NO_ACTION, &digest_list,
  

•                               sizeof(locality_event), (u8*)&locality_event);
  

•   if (ret != EFI_SUCCESS)
  

•           goto out;
  

•   ret = create_final_event();
  
  

out:

2.31.0