security/tpm: replace TPM_MEASURE_ALGO with tpm_log_alg()

No functional changes.  This replaces a macro with an inline function to
make code more readable and more convenient to extend in the future.

Change-Id: I456bc3bb749a9b58fba72f5562195525e55290bf
Signed-off-by: Sergii Dmytruk <[email protected]>

Author: SergiiDmytruk

src/lib/cbfs.c

@@ -189,9 +189,9 @@ static bool cbfs_file_hash_mismatch(const void *buffer, size_t size,
 		struct vb2_hash calculated_hash;
 
 		/* No need to re-hash file if we already have it from verification. */
-		if (!hash || hash->algo != TPM_MEASURE_ALGO) {
+		if (!hash || hash->algo != tpm_log_alg()) {
 			if (vb2_hash_calculate(vboot_hwcrypto_allowed(), buffer, size,
-					       TPM_MEASURE_ALGO, &calculated_hash))
+					       tpm_log_alg(), &calculated_hash))
 				hash = NULL;
 			else
 				hash = &calculated_hash;

src/security/tpm/tspi.h

@@ -17,6 +17,31 @@
 /* Assumption of 2K TCPA log size reserved for CAR/SRAM */
 #define MAX_PRERAM_TPM_LOG_ENTRIES 15
 
+/**
+ * Retrieves hash algorithm used by TPM event log or VB2_HASH_INVALID.
+ */
+static inline enum vb2_hash_algorithm tpm_log_alg(void)
+{
+	if (CONFIG(TPM_LOG_CB))
+		return (tlcl_get_family() == TPM_1 ? VB2_HASH_SHA1 : VB2_HASH_SHA256);
+
+	if (CONFIG(TPM_LOG_TPM1))
+		return VB2_HASH_SHA1;
+
+	if (CONFIG(TPM_LOG_TPM2)) {
+		if (CONFIG(TPM_HASH_SHA1))
+			return VB2_HASH_SHA1;
+		if (CONFIG(TPM_HASH_SHA256))
+			return VB2_HASH_SHA256;
+		if (CONFIG(TPM_HASH_SHA384))
+			return VB2_HASH_SHA384;
+		if (CONFIG(TPM_HASH_SHA512))
+			return VB2_HASH_SHA512;
+	}
+
+	return VB2_HASH_INVALID;
+}
+
 /**
  * Get the pointer to the single instance of global
  * TPM log data, and initialize it when necessary

src/security/tpm/tspi/crtm.h

@@ -9,33 +9,6 @@
 #include <types.h>
 #include <vb2_sha.h>
 
-#if CONFIG(TPM_LOG_CB)
-#  define TPM_MEASURE_ALGO (tlcl_get_family() == TPM_1 ? VB2_HASH_SHA1 : VB2_HASH_SHA256)
-#elif CONFIG(TPM_LOG_TPM1)
-#  define TPM_MEASURE_ALGO VB2_HASH_SHA1
-#elif CONFIG(TPM_LOG_TPM2)
-#  if CONFIG(TPM_HASH_SHA1)
-#    define TPM_MEASURE_ALGO VB2_HASH_SHA1
-#  endif
-#  if CONFIG(TPM_HASH_SHA256)
-#    define TPM_MEASURE_ALGO VB2_HASH_SHA256
-#  endif
-#  if CONFIG(TPM_HASH_SHA384)
-#    define TPM_MEASURE_ALGO VB2_HASH_SHA384
-#  endif
-#  if CONFIG(TPM_HASH_SHA512)
-#    define TPM_MEASURE_ALGO VB2_HASH_SHA512
-#  endif
-#endif
-
-#if !defined(TPM_MEASURE_ALGO)
-#  if !CONFIG(TPM_MEASURED_BOOT)
-#    define TPM_MEASURE_ALGO VB2_HASH_INVALID
-#  else
-#    error "Misconfiguration: failed to determine TPM hashing algorithm"
-#  endif
-#endif
-
 /**
  * Measure digests cached in TPM log entries into PCRs
  */

src/security/tpm/tspi/log-tpm2.c

@@ -71,8 +71,8 @@ void *tpm2_log_cbmem_init(void)
 		hdr->spec_errata = 0x00;
 		hdr->uintn_size = 0x02; // 64-bit UINT
 		hdr->num_of_algorithms = htole32(1);
-		hdr->digest_sizes[0].alg_id = htole16(tpmalg_from_vb2_hash(TPM_MEASURE_ALGO));
-		hdr->digest_sizes[0].digest_size = htole16(vb2_digest_size(TPM_MEASURE_ALGO));
+		hdr->digest_sizes[0].alg_id = htole16(tpmalg_from_vb2_hash(tpm_log_alg()));
+		hdr->digest_sizes[0].digest_size = htole16(vb2_digest_size(tpm_log_alg()));
 
 		tclt->vendor_info_size = sizeof(tclt->vendor);
 		tclt->vendor.reserved = 0;
@@ -98,8 +98,8 @@ void tpm2_log_dump(void)
 	if (!tclt)
 		return;
 
-	hash_size = vb2_digest_size(TPM_MEASURE_ALGO);
-	alg_name = vb2_get_hash_algorithm_name(TPM_MEASURE_ALGO);
+	hash_size = vb2_digest_size(tpm_log_alg());
+	alg_name = vb2_get_hash_algorithm_name(tpm_log_alg());
 
 	printk(BIOS_INFO, "coreboot TPM 2.0 measurements:\n\n");
 	for (i = 0; i < le16toh(tclt->vendor.num_entries); i++) {
@@ -134,13 +134,13 @@ void tpm2_log_add_table_entry(const char *name, const uint32_t pcr,
 		return;
 	}
 
-	if (digest_algo != TPM_MEASURE_ALGO) {
+	if (digest_algo != tpm_log_alg()) {
 		printk(BIOS_WARNING, "TPM LOG: digest is of unsupported type: %s\n",
 		       vb2_get_hash_algorithm_name(digest_algo));
 		return;
 	}
 
-	if (digest_len != vb2_digest_size(TPM_MEASURE_ALGO)) {
+	if (digest_len != vb2_digest_size(tpm_log_alg())) {
 		printk(BIOS_WARNING, "TPM LOG: digest has invalid length: %d\n",
 		       (int)digest_len);
 		return;
@@ -158,8 +158,8 @@ void tpm2_log_add_table_entry(const char *name, const uint32_t pcr,
 	tce->event_type = htole32(EV_ACTION);
 
 	tce->digest_count = htole32(1);
-	tce->digest_type = htole16(tpmalg_from_vb2_hash(TPM_MEASURE_ALGO));
-	memcpy(tce->digest, digest, vb2_digest_size(TPM_MEASURE_ALGO));
+	tce->digest_type = htole16(tpmalg_from_vb2_hash(tpm_log_alg()));
+	memcpy(tce->digest, digest, vb2_digest_size(tpm_log_alg()));
 
 	tce->data_length = htole32(sizeof(tce->data));
 	strncpy((char *)tce->data, name, sizeof(tce->data) - 1);
@@ -183,7 +183,7 @@ int tpm2_log_get(int entry_idx, int *pcr, const uint8_t **digest_data,
 
 	*pcr = le32toh(tce->pcr);
 	*digest_data = tce->digest;
-	*digest_algo = TPM_MEASURE_ALGO; /* We validate algorithm on addition */
+	*digest_algo = tpm_log_alg(); /* We validate algorithm on addition */
 	*event_name = (char *)tce->data;
 	return 0;
 }

src/security/tpm/tspi/tspi.c

@@ -265,9 +265,9 @@ tpm_result_t tpm_measure_region(const struct region_device *rdev, uint8_t pcr,
 	if (!rdev || !rname)
 		return TPM_CB_INVALID_ARG;
 
-	digest_len = vb2_digest_size(TPM_MEASURE_ALGO);
+	digest_len = vb2_digest_size(tpm_log_alg());
 	assert(digest_len <= sizeof(digest));
-	if (vb2_digest_init(&ctx, vboot_hwcrypto_allowed(), TPM_MEASURE_ALGO,
+	if (vb2_digest_init(&ctx, vboot_hwcrypto_allowed(), tpm_log_alg(),
 			    region_device_sz(rdev))) {
 		printk(BIOS_ERR, "TPM: Error initializing hash.\n");
 		return TPM_CB_HASH_ERROR;
@@ -293,6 +293,6 @@ tpm_result_t tpm_measure_region(const struct region_device *rdev, uint8_t pcr,
 		printk(BIOS_ERR, "TPM: Error finalizing hash.\n");
 		return TPM_CB_HASH_ERROR;
 	}
-	return tpm_extend_pcr(pcr, TPM_MEASURE_ALGO, digest, digest_len, rname);
+	return tpm_extend_pcr(pcr, tpm_log_alg(), digest, digest_len, rname);
 }
 #endif /* VBOOT_LIB */