security/tpm: Add TCPA logging functionality

* TCG spec only applies to BIOS or UEFI.
* Therefore implement coreboot TCPA compliant log
in CBMEM.
* Write CBMEM log into the coreboot table for CBMEM tool access

Change-Id: I0a52494f647d21e2587231af26ed13d62b3a72f5
Signed-off-by: Philipp Deppenwiese <zaolin@das-labor.org>
Reviewed-on: https://review.coreboot.org/22867
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/commonlib/include/commonlib/cbmem_id.h

@@ -64,6 +64,7 @@
 #define CBMEM_ID_STAGEx_RAW	0x57a9e200
 #define CBMEM_ID_STORAGE_DATA	0x53746f72
 #define CBMEM_ID_TCPA_LOG	0x54435041
+#define CBMEM_ID_TCPA_COMPLIANT_LOG 0x54445041
 #define CBMEM_ID_TIMESTAMP	0x54494d45
 #define CBMEM_ID_VBOOT_HANDOFF	0x780074f0
 #define CBMEM_ID_VBOOT_SEL_REG	0x780074f1
@@ -120,6 +121,7 @@
 	{ CBMEM_ID_SMM_SAVE_SPACE,	"SMM BACKUP " }, \
 	{ CBMEM_ID_STORAGE_DATA,	"SD/MMC/eMMC" }, \
 	{ CBMEM_ID_TCPA_LOG,		"TCPA LOG   " }, \
+	{ CBMEM_ID_TCPA_COMPLIANT_LOG,	"TCPA COMPLIANT LOG   " }, \
 	{ CBMEM_ID_TIMESTAMP,		"TIME STAMP " }, \
 	{ CBMEM_ID_VBOOT_HANDOFF,	"VBOOT      " }, \
 	{ CBMEM_ID_VBOOT_SEL_REG,	"VBOOT SEL  " }, \

src/commonlib/include/commonlib/tcpa_log_serialized.h

@@ -0,0 +1,41 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Facebook Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __TCPA_LOG_SERIALIZED_H__
+#define __TCPA_LOG_SERIALIZED_H__
+
+#include <compiler.h>
+#include <stdint.h>
+
+#define MAX_TCPA_LOG_ENTRIES 50
+#define TCPA_LOG_STRING_LENGTH 512
+#define TCPA_FORMAT_HASH_LENGTH 128
+#define TCPA_DIGEST_MAX_LENGTH 64
+#define TCPA_PCR_HASH_NAME 256
+
+struct tcpa_entry {
+	uint32_t pcr;
+	uint8_t digest[TCPA_DIGEST_MAX_LENGTH];
+	uint32_t digest_length;
+	uint8_t name[TCPA_PCR_HASH_NAME];
+} __packed;
+
+struct tcpa_table {
+	uint16_t max_entries;
+	uint16_t num_entries;
+	struct tcpa_entry entries[0]; /* Variable number of entries */
+} __packed;
+
+#endif

src/drivers/tpm/tpm.c

@@ -30,6 +30,9 @@ static void init_tpm_dev(void *unused)
 #else
 	tpm_setup(false);
 #endif
+
+	// TCPA cbmem log
+	tcpa_log_init();
 }
 
 BOOT_STATE_INIT_ENTRY(BS_DEV_INIT, BS_ON_ENTRY, init_tpm_dev, NULL);

src/security/tpm/Makefile.inc

@@ -12,11 +12,11 @@ postcar-$(CONFIG_VBOOT) += tss/tcg-1.2/tss.c
 
 ## TSPI
 
-ramstage-y += tspi/tspi.c
-romstage-y += tspi/tspi.c
+ramstage-y += tspi/tspi.c tspi/log.c
+romstage-y += tspi/tspi.c tspi/log.c
 
-verstage-$(CONFIG_VBOOT) += tspi/tspi.c
-postcar-$(CONFIG_VBOOT) += tspi/tspi.c
+verstage-$(CONFIG_VBOOT) += tspi/tspi.c tspi/log.c
+postcar-$(CONFIG_VBOOT) += tspi/tspi.c tspi/log.c
 
 endif # CONFIG_TPM1
 
@@ -36,10 +36,10 @@ postcar-$(CONFIG_VBOOT) += tss/tcg-2.0/tss.c
 
 ## TSPI
 
-ramstage-y += tspi/tspi.c
-romstage-y += tspi/tspi.c
+ramstage-y += tspi/tspi.c tspi/log.c
+romstage-y += tspi/tspi.c tspi/log.c
 
-verstage-$(CONFIG_VBOOT) += tspi/tspi.c
-postcar-$(CONFIG_VBOOT) += tspi/tspi.c
+verstage-$(CONFIG_VBOOT) += tspi/tspi.c tspi/log.c
+postcar-$(CONFIG_VBOOT) += tspi/tspi.c tspi/log.c
 
 endif # CONFIG_TPM2

src/security/tpm/tspi.h

@@ -18,6 +18,18 @@
 #define TSPI_H_
 
 #include <security/tpm/tss.h>
+#include <commonlib/tcpa_log_serialized.h>
+
+/**
+ * Setup TCPA cbmem log.
+ */
+void tcpa_log_init(void);
+
+/**
+ * Add table entry for cbmem TCPA log.
+ */
+int tcpa_log_add_table_entry(const char *name, const uint32_t pcr,
+			     const uint8_t *digest, const size_t digest_length);
 
 /**
  * Ask vboot for a digest and extend a TPM PCR with it.

src/security/tpm/tspi/log.c

@@ -0,0 +1,75 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 Facebook Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <string.h>
+#include <cbmem.h>
+#include <console/console.h>
+#include <security/tpm/tspi.h>
+
+void tcpa_log_init(void)
+{
+	const struct cbmem_entry *ce;
+	struct tcpa_table *tclt;
+
+	if (!cbmem_possibly_online())
+		return;
+
+	ce = cbmem_entry_find(CBMEM_ID_TCPA_LOG);
+	if (ce)
+		return;
+
+	tclt = cbmem_add(CBMEM_ID_TCPA_LOG,
+			 sizeof(struct tcpa_table) +
+				 MAX_TCPA_LOG_ENTRIES *
+					 sizeof(struct tcpa_entry));
+
+	if (!tclt)
+		return;
+
+	tclt->max_entries = MAX_TCPA_LOG_ENTRIES;
+	tclt->num_entries = 0;
+
+	printk(BIOS_DEBUG, "TCPA log created at %p\n", tclt);
+}
+
+int tcpa_log_add_table_entry(const char *name, const uint32_t pcr,
+			     const uint8_t *digest, const size_t digest_length)
+{
+	MAYBE_STATIC struct tcpa_table *tclt = NULL;
+	struct tcpa_entry *tce;
+
+	if (!cbmem_possibly_online())
+		return -1;
+
+	tclt = cbmem_find(CBMEM_ID_TCPA_LOG);
+	if (!tclt) {
+		printk(BIOS_ERR, "ERROR: No TCPA log table found\n");
+		return -1;
+	}
+
+	if (tclt->num_entries == tclt->max_entries) {
+		printk(BIOS_WARNING, "ERROR: TCPA log table is full\n");
+		return -1;
+	}
+
+	tce = &tclt->entries[tclt->num_entries++];
+
+	memcpy(tce->name, name, TCPA_PCR_HASH_NAME);
+	tce->pcr = pcr;
+	memcpy(tce->digest, digest, digest_length);
+	tce->digest_length = digest_length;
+
+	return 0;
+}