security/vboot: Enable TCPA log extension

* Implement TCPA log for tspi extend function.
* Hook tcpa_log_init into vboot tpm_setup function.
* Add TCPA log output for vboot GBB flags and HWID

Change-Id: I22b1aa8da1a95380c39715727615ce5ce4c9443f
Signed-off-by: Philipp Deppenwiese <zaolin@das-labor.org>
Reviewed-on: https://review.coreboot.org/27727
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/security/tpm/tspi.h

@@ -35,10 +35,12 @@ int tcpa_log_add_table_entry(const char *name, const uint32_t pcr,
  * Ask vboot for a digest and extend a TPM PCR with it.
  * @param pcr sets the pcr index
  * @param digest sets the hash to extend into the tpm
- * @param out_digest get extended hash
+ * @param digest_len the length of the digest
+ * @param name sets additional info where the digest comes from
  * @return TPM_SUCCESS on success. If not a tpm error is returned
  */
-uint32_t tpm_extend_pcr(int pcr, uint8_t *digest, uint8_t *out_digest);
+uint32_t tpm_extend_pcr(int pcr, uint8_t *digest, size_t digest_len,
+			const char *name);
 
 /**
  * Issue a TPM_Clear and reenable/reactivate the TPM.

src/security/tpm/tspi/tspi.c

@@ -178,13 +178,21 @@ uint32_t tpm_clear_and_reenable(void)
 	return TPM_SUCCESS;
 }
 
-uint32_t tpm_extend_pcr(int pcr, uint8_t *digest, uint8_t *out_digest)
+uint32_t tpm_extend_pcr(int pcr, uint8_t *digest,
+			size_t digest_len, const char *name)
 {
+	uint32_t result;
+
 	if (!digest)
 		return TPM_E_IOERROR;
 
-	if (out_digest)
-		return tlcl_extend(pcr, digest, out_digest);
+	result = tlcl_extend(pcr, digest, NULL);
+	if (result != TPM_SUCCESS)
+		return result;
 
-	return tlcl_extend(pcr, digest, NULL);
+	result = tcpa_log_add_table_entry(name, pcr, digest, digest_len);
+	if (result != 0)
+		printk(BIOS_ERR, "ERROR: Couldn't create TCPA log entry\n");
+
+	return 0;
 }

src/security/vboot/secdata_tpm.c

@@ -61,6 +61,8 @@
 		}							\
 	} while (0)
 
+#define TPM_PCR_GBB_FLAGS_NAME "GBB flags"
+#define TPM_PCR_GBB_HWID_NAME "GBB HWID"
 
 static uint32_t safe_write(uint32_t index, const void *data, uint32_t length);
 
@@ -77,7 +79,15 @@ uint32_t vboot_extend_pcr(struct vb2_context *ctx, int pcr,
 	if (size < TPM_PCR_MINIMUM_DIGEST_SIZE)
 		return VB2_ERROR_UNKNOWN;
 
-	return tpm_extend_pcr(pcr, buffer, NULL);
+	switch (which_digest) {
+	case BOOT_MODE_PCR:
+		return tpm_extend_pcr(pcr, buffer, size,
+				      TPM_PCR_GBB_FLAGS_NAME);
+	case HWID_DIGEST_PCR:
+		return tpm_extend_pcr(pcr, buffer, size, TPM_PCR_GBB_HWID_NAME);
+	default:
+		return VB2_ERROR_UNKNOWN;
+	}
 }
 
 static uint32_t read_space_firmware(struct vb2_context *ctx)
@@ -441,6 +451,9 @@ uint32_t vboot_setup_tpm(struct vb2_context *ctx)
 	if (result == TPM_E_MUST_REBOOT)
 		ctx->flags |= VB2_CONTEXT_SECDATA_WANTS_REBOOT;
 
+	// TCPA cbmem log
+	tcpa_log_init();
+
 	return result;
 }