security/vboot: Decouple measured boot from verified boot

Currently, those who want to use measured boot implemented within
vboot should enable verified boot first, along with sections such
as GBB and RW slots defined with manually written fmd files, even
if they do not actually want to verify anything.

As discussed in CB:34977, measured boot should be decoupled from
verified boot and make them two fully independent options. Crypto
routines necessary for measurement could be reused, and TPM and CRTM
init should be done somewhere other than vboot_logic_executed() if
verified boot is not enabled.

In this revision, only TCPA log is initialized during bootblock.
Before TPM gets set up, digests are not measured into tpm immediately,
but cached in TCPA log, and measured into determined PCRs right after
TPM is up.

This change allows those who do not want to use the verified boot
scheme implemented by vboot as well as its requirement of a more
complex partition scheme designed for chromeos to make use of the
measured boot functionality implemented within vboot library to
measure the boot process.

TODO: Measure MRC Cache somewhere, as MRC Cache has never resided in
CBFS any more, so it cannot be covered by tspi_measure_cbfs_hook().

Change-Id: I1fb376b4a8b98baffaee4d574937797bba1f8aee
Signed-off-by: Bill XIE <persmule@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35077
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>

1 files changed, 197 insertions, 0 deletions

diff --git a/src/security/tpm/tspi/crtm.c b/src/security/tpm/tspi/crtm.c
new file mode 100644
index 0000000000..dc7d7d21f0
--- /dev/null
+++ b/src/security/tpm/tspi/crtm.c
@@ -0,0 +1,197 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ *
+ * 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 <console/console.h>
+#include <fmap.h>
+#include <cbfs.h>
+#include "crtm.h"
+#include <string.h>
+
+/*
+ * This function sets the TCPA log namespace
+ * for the cbfs file (region) lookup.
+ */
+static int create_tcpa_metadata(const struct region_device *rdev,
+		const char *cbfs_name, char log_string[TCPA_PCR_HASH_NAME])
+{
+	int i;
+	struct region_device fmap;
+	static const char *const fmap_cbfs_names[] = {
+		"COREBOOT",
+		"FW_MAIN_A",
+		"FW_MAIN_B",
+		"RW_LEGACY"
+	};
+
+	for (i = 0; i < ARRAY_SIZE(fmap_cbfs_names); i++) {
+		if (fmap_locate_area_as_rdev(fmap_cbfs_names[i], &fmap) == 0) {
+			if (region_is_subregion(region_device_region(&fmap),
+				region_device_region(rdev))) {
+				snprintf(log_string, TCPA_PCR_HASH_NAME,
+					"FMAP: %s CBFS: %s",
+					fmap_cbfs_names[i], cbfs_name);
+				return 0;
+			}
+		}
+	}
+
+	return -1;
+}
+
+static int tcpa_log_initialized;
+static inline int tcpa_log_available(void)
+{
+	if (ENV_BOOTBLOCK)
+		return tcpa_log_initialized;
+
+	return 1;
+}
+
+uint32_t tspi_init_crtm(void)
+{
+	struct prog bootblock = PROG_INIT(PROG_BOOTBLOCK, "bootblock");
+
+	/* Initialize TCPA PRERAM log. */
+	if (!tcpa_log_available()) {
+		tcpa_preram_log_clear();
+		tcpa_log_initialized = 1;
+	} else {
+		printk(BIOS_WARNING, "TSPI: CRTM already initialized!\n");
+		return VB2_SUCCESS;
+	}
+
+	/* measure bootblock from RO */
+	struct cbfsf bootblock_data;
+	struct region_device bootblock_fmap;
+	if (fmap_locate_area_as_rdev("BOOTBLOCK", &bootblock_fmap) == 0) {
+		if (tpm_measure_region(&bootblock_fmap,
+				       TPM_CRTM_PCR,
+				       "FMAP: BOOTBLOCK"))
+			return VB2_ERROR_UNKNOWN;
+	} else {
+		if (cbfs_boot_locate(&bootblock_data,
+			prog_name(&bootblock), NULL)) {
+			/*
+			 * measurement is done in
+			 * tspi_measure_cbfs_hook()
+			 */
+			printk(BIOS_INFO,
+			       "TSPI: Couldn't measure bootblock into CRTM!\n");
+			return VB2_ERROR_UNKNOWN;
+		}
+	}
+
+	return VB2_SUCCESS;
+}
+
+static bool is_runtime_data(const char *name)
+{
+	const char *whitelist = CONFIG_TPM_MEASURED_BOOT_RUNTIME_DATA;
+	size_t whitelist_len = sizeof(CONFIG_TPM_MEASURED_BOOT_RUNTIME_DATA) - 1;
+	size_t name_len = strlen(name);
+	int i;
+
+	if (!whitelist_len || !name_len)
+		return false;
+
+	for (i = 0; (i + name_len) <= whitelist_len; i++) {
+		if (!strcmp(whitelist + i, name))
+			return true;
+	}
+
+	return false;
+}
+
+uint32_t tspi_measure_cbfs_hook(struct cbfsf *fh, const char *name)
+{
+	uint32_t pcr_index;
+	uint32_t cbfs_type;
+	struct region_device rdev;
+	char tcpa_metadata[TCPA_PCR_HASH_NAME];
+
+	if (!tcpa_log_available()) {
+		if (tspi_init_crtm() != VB2_SUCCESS) {
+			printk(BIOS_WARNING,
+			       "Initializing CRTM failed!");
+			return 0;
+		}
+		printk(BIOS_DEBUG, "CRTM initialized.");
+	}
+
+	cbfsf_file_type(fh, &cbfs_type);
+	cbfs_file_data(&rdev, fh);
+
+	switch (cbfs_type) {
+	case CBFS_TYPE_MRC:
+	case CBFS_TYPE_MRC_CACHE:
+		pcr_index = TPM_RUNTIME_DATA_PCR;
+		break;
+	case CBFS_TYPE_STAGE:
+	case CBFS_TYPE_SELF:
+	case CBFS_TYPE_FIT:
+		pcr_index = TPM_CRTM_PCR;
+		break;
+	default:
+		if (is_runtime_data(name))
+			pcr_index = TPM_RUNTIME_DATA_PCR;
+		else
+			pcr_index = TPM_CRTM_PCR;
+		break;
+	}
+
+	if (create_tcpa_metadata(&rdev, name, tcpa_metadata) < 0)
+		return VB2_ERROR_UNKNOWN;
+
+	return tpm_measure_region(&rdev, pcr_index, tcpa_metadata);
+}
+
+int tspi_measure_cache_to_pcr(void)
+{
+	int i;
+	enum vb2_hash_algorithm hash_alg;
+	struct tcpa_table *tclt = tcpa_log_init();
+
+	if (!tclt) {
+		printk(BIOS_WARNING, "TCPA: Log non-existent!\n");
+		return VB2_ERROR_UNKNOWN;
+	}
+	if (CONFIG(TPM1)) {
+		hash_alg = VB2_HASH_SHA1;
+	} else { /* CONFIG_TPM2 */
+		hash_alg = VB2_HASH_SHA256;
+	}
+
+
+	printk(BIOS_DEBUG, "TPM: Write digests cached in TCPA log to PCR\n");
+	for (i = 0; i < tclt->num_entries; i++) {
+		struct tcpa_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,
+						 NULL);
+			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;
+			}
+		}
+	}
+
+	return VB2_SUCCESS;
+}