security/tpm: make tspi/crtm.c agnostic to log format

Change-Id: I3013bd5f29f1412fbe646dc74d8946704b750a66
Ticket: https://ticket.coreboot.org/issues/423
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69445
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

3 files changed, 132 insertions, 67 deletions

diff --git a/src/security/tpm/tspi.h b/src/security/tpm/tspi.h
index aee38aa902..b081439c44 100644
--- a/src/security/tpm/tspi.h
+++ b/src/security/tpm/tspi.h
@@ -10,12 +10,21 @@
 
 #define TPM_PCR_MAX_LEN 64
 #define HASH_DATA_CHUNK_SIZE 1024
+#define MAX_TPM_LOG_ENTRIES 50
+/* Assumption of 2K TCPA log size reserved for CAR/SRAM */
+#define MAX_PRERAM_TPM_LOG_ENTRIES 15
 
 /**
  * Get the pointer to the single instance of global
  * TPM log data, and initialize it when necessary
  */
-struct tpm_cb_log_table *tpm_log_init(void);
+void *tpm_log_init(void);
+
+/**
+ * Get the pointer to the single CBMEM instance of global
+ * TPM log data, and initialize it when necessary
+ */
+void *tpm_log_cbmem_init(void);
 
 /**
  * Clears the pre-RAM TPM log data and initializes
@@ -24,6 +33,22 @@ struct tpm_cb_log_table *tpm_log_init(void);
 void tpm_preram_log_clear(void);
 
 /**
+ * Retrieves number of entries currently stored in the log.
+ */
+uint16_t tpm_log_get_size(const void *log_table);
+
+/**
+ * Copies data from pre-RAM TPM log to CBMEM (RAM) log
+ */
+void tpm_log_copy_entries(const void *from, void *to);
+
+/**
+ * Retrieves an entry from a log. Returns non-zero on invalid index or error.
+ */
+int tpm_log_get(int entry_idx, int *pcr, const uint8_t **digest_data,
+		enum vb2_hash_algorithm *digest_algo, const char **event_name);
+
+/**
  * Add table entry for cbmem TPM log.
  * @param name Name of the hashed data
  * @param pcr PCR used to extend hashed data
diff --git a/src/security/tpm/tspi/crtm.c b/src/security/tpm/tspi/crtm.c
index 6e4fadad2b..a7efcf2145 100644
--- a/src/security/tpm/tspi/crtm.c
+++ b/src/security/tpm/tspi/crtm.c
@@ -2,7 +2,9 @@
 
 #include <console/console.h>
 #include <fmap.h>
+#include <bootstate.h>
 #include <cbfs.h>
+#include <symbols.h>
 #include "crtm.h"
 #include <string.h>
 
@@ -148,39 +150,79 @@ uint32_t tspi_cbfs_measurement(const char *name, uint32_t type, const struct vb2
 			      tpm_log_metadata);
 }
 
+void *tpm_log_init(void)
+{
+	static void *tclt;
+
+	/* We are dealing here with pre CBMEM environment.
+	 * If cbmem isn't available use CAR or SRAM */
+	if (!cbmem_possibly_online() &&
+		!CONFIG(VBOOT_RETURN_FROM_VERSTAGE))
+		return _tpm_log;
+	else if (ENV_CREATES_CBMEM
+		 && !CONFIG(VBOOT_RETURN_FROM_VERSTAGE)) {
+		tclt = tpm_log_cbmem_init();
+		if (!tclt)
+			return _tpm_log;
+	} else {
+		tclt = tpm_log_cbmem_init();
+	}
+
+	return tclt;
+}
+
 int tspi_measure_cache_to_pcr(void)
 {
 	int i;
-	struct tpm_cb_log_table *tclt = tpm_log_init();
+	int pcr;
+	const char *event_name;
+	const uint8_t *digest_data;
+	enum vb2_hash_algorithm digest_algo;
 
 	/* This means the table is empty. */
 	if (!tpm_log_available())
 		return VB2_SUCCESS;
 
-	if (!tclt) {
+	if (tpm_log_init() == NULL) {
 		printk(BIOS_WARNING, "TPM LOG: log non-existent!\n");
 		return VB2_ERROR_UNKNOWN;
 	}
 
 	printk(BIOS_DEBUG, "TPM: Write digests cached in TPM log to PCR\n");
-	for (i = 0; i < tclt->num_entries; i++) {
-		struct tpm_cb_log_entry *tce = &tclt->entries[i];
-		if (tce) {
-			printk(BIOS_DEBUG, "TPM: Write digest for"
-			       " %s into PCR %d\n",
-			       tce->name, tce->pcr);
-			int result = tlcl_extend(tce->pcr,
-						 tce->digest,
-						 TPM_MEASURE_ALGO);
-			if (result != TPM_SUCCESS) {
-				printk(BIOS_ERR, "TPM: Writing digest"
-				       " of %s into PCR failed with error"
-				       " %d\n",
-				       tce->name, result);
-				return VB2_ERROR_UNKNOWN;
-			}
+	i = 0;
+	while (!tpm_log_get(i++, &pcr, &digest_data, &digest_algo, &event_name)) {
+		printk(BIOS_DEBUG, "TPM: Write digest for %s into PCR %d\n", event_name, pcr);
+		int result = tlcl_extend(pcr, digest_data, digest_algo);
+		if (result != TPM_SUCCESS) {
+			printk(BIOS_ERR,
+			       "TPM: Writing digest of %s into PCR failed with error %d\n",
+				event_name, result);
+			return VB2_ERROR_UNKNOWN;
 		}
 	}
 
 	return VB2_SUCCESS;
 }
+
+#if !CONFIG(VBOOT_RETURN_FROM_VERSTAGE)
+static void recover_tpm_log(int is_recovery)
+{
+	const void *preram_log = _tpm_log;
+	void *ram_log = tpm_log_cbmem_init();
+
+	if (tpm_log_get_size(preram_log) > MAX_PRERAM_TPM_LOG_ENTRIES) {
+		printk(BIOS_WARNING, "TPM LOG: pre-RAM log is too full, possible corruption\n");
+		return;
+	}
+
+	if (ram_log == NULL) {
+		printk(BIOS_WARNING, "TPM LOG: CBMEM not available, something went wrong\n");
+		return;
+	}
+
+	tpm_log_copy_entries(_tpm_log, ram_log);
+}
+CBMEM_CREATION_HOOK(recover_tpm_log);
+#endif
+
+BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_BOOT, BS_ON_ENTRY, tpm_log_dump, NULL);
diff --git a/src/security/tpm/tspi/log.c b/src/security/tpm/tspi/log.c
index fa95b80e81..96c3087f95 100644
--- a/src/security/tpm/tspi/log.c
+++ b/src/security/tpm/tspi/log.c
@@ -6,10 +6,9 @@
 #include <string.h>
 #include <symbols.h>
 #include <cbmem.h>
-#include <bootstate.h>
 #include <vb2_sha.h>
 
-static struct tpm_cb_log_table *tpm_log_cbmem_init(void)
+void *tpm_log_cbmem_init(void)
 {
 	static struct tpm_cb_log_table *tclt;
 	if (tclt)
@@ -30,27 +29,6 @@ static struct tpm_cb_log_table *tpm_log_cbmem_init(void)
 	return tclt;
 }
 
-struct tpm_cb_log_table *tpm_log_init(void)
-{
-	static struct tpm_cb_log_table *tclt;
-
-	/* We are dealing here with pre CBMEM environment.
-	 * If cbmem isn't available use CAR or SRAM */
-	if (!cbmem_possibly_online() &&
-		!CONFIG(VBOOT_RETURN_FROM_VERSTAGE))
-		return (struct tpm_cb_log_table *)_tpm_log;
-	else if (ENV_CREATES_CBMEM
-		 && !CONFIG(VBOOT_RETURN_FROM_VERSTAGE)) {
-		tclt = tpm_log_cbmem_init();
-		if (!tclt)
-			return (struct tpm_cb_log_table *)_tpm_log;
-	} else {
-		tclt = tpm_log_cbmem_init();
-	}
-
-	return tclt;
-}
-
 void tpm_log_dump(void *unused)
 {
 	int i, j;
@@ -121,42 +99,62 @@ void tpm_preram_log_clear(void)
 	tclt->num_entries = 0;
 }
 
-#if !CONFIG(VBOOT_RETURN_FROM_VERSTAGE)
-static void recover_tpm_log(int is_recovery)
+int tpm_log_get(int entry_idx, int *pcr, const uint8_t **digest_data,
+		enum vb2_hash_algorithm *digest_algo, const char **event_name)
 {
-	struct tpm_cb_log_table *preram_log = (struct tpm_cb_log_table *)_tpm_log;
-	struct tpm_cb_log_table *ram_log = NULL;
-	int i;
+	struct tpm_cb_log_table *tclt;
+	struct tpm_cb_log_entry *tce;
+	enum vb2_hash_algorithm algo;
 
-	if (preram_log->num_entries > MAX_PRERAM_TPM_LOG_ENTRIES) {
-		printk(BIOS_WARNING, "TPM LOG: pre-RAM log is too full, possible corruption\n");
-		return;
-	}
+	tclt = tpm_log_init();
+	if (!tclt)
+		return 1;
 
-	ram_log = tpm_log_cbmem_init();
-	if (!ram_log) {
-		printk(BIOS_WARNING, "TPM LOG: CBMEM not available something went wrong\n");
-		return;
+	if (entry_idx < 0 || entry_idx >= tclt->num_entries)
+		return 1;
+
+	tce = &tclt->entries[entry_idx];
+
+	*pcr = tce->pcr;
+	*digest_data = tce->digest;
+	*event_name = tce->name;
+
+	*digest_algo = VB2_HASH_INVALID;
+	for (algo = VB2_HASH_INVALID; algo != VB2_HASH_ALG_COUNT; ++algo) {
+		if (strcmp(tce->digest_type, vb2_hash_names[algo]) == 0) {
+			*digest_algo = algo;
+			break;
+		}
 	}
+	return 0;
+}
 
-	for (i = 0; i < preram_log->num_entries; i++) {
-		struct tpm_cb_log_entry *tce = &ram_log->entries[ram_log->num_entries++];
-		strncpy(tce->name, preram_log->entries[i].name, TPM_CB_LOG_PCR_HASH_NAME - 1);
-		tce->pcr = preram_log->entries[i].pcr;
+uint16_t tpm_log_get_size(const void *log_table)
+{
+	const struct tpm_cb_log_table *tclt = log_table;
+	return tclt->num_entries;
+}
+
+void tpm_log_copy_entries(const void *from, void *to)
+{
+	const struct tpm_cb_log_table *from_log = from;
+	struct tpm_cb_log_table *to_log = to;
+	int i;
+
+	for (i = 0; i < from_log->num_entries; i++) {
+		struct tpm_cb_log_entry *tce = &to_log->entries[to_log->num_entries++];
+		strncpy(tce->name, from_log->entries[i].name, TPM_CB_LOG_PCR_HASH_NAME - 1);
+		tce->pcr = from_log->entries[i].pcr;
 
-		if (preram_log->entries[i].digest_length > TPM_CB_LOG_DIGEST_MAX_LENGTH) {
+		if (from_log->entries[i].digest_length > TPM_CB_LOG_DIGEST_MAX_LENGTH) {
 			printk(BIOS_WARNING, "TPM LOG: PCR digest too long for log entry\n");
 			return;
 		}
 
-		strncpy(tce->digest_type, preram_log->entries[i].digest_type,
+		strncpy(tce->digest_type, from_log->entries[i].digest_type,
 			TPM_CB_LOG_PCR_HASH_LEN - 1);
-		tce->digest_length = MIN(preram_log->entries[i].digest_length,
+		tce->digest_length = MIN(from_log->entries[i].digest_length,
 					 TPM_CB_LOG_DIGEST_MAX_LENGTH);
-		memcpy(tce->digest, preram_log->entries[i].digest, tce->digest_length);
+		memcpy(tce->digest, from_log->entries[i].digest, tce->digest_length);
 	}
 }
-CBMEM_CREATION_HOOK(recover_tpm_log);
-#endif
-
-BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_BOOT, BS_ON_ENTRY, tpm_log_dump, NULL);