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>

7 files changed, 356 insertions, 39 deletions

diff --git a/src/security/tpm/Kconfig b/src/security/tpm/Kconfig
index 1766939c4c..d8652b2017 100644
--- a/src/security/tpm/Kconfig
+++ b/src/security/tpm/Kconfig
@@ -100,4 +100,21 @@ config TPM_STARTUP_IGNORE_POSTINIT
 	  or VBOOT on the Intel Arrandale processor, which issues a
 	  CPU-only reset during the romstage.
 
+config TPM_MEASURED_BOOT
+	bool "Enable Measured Boot"
+	default n
+	select VBOOT_LIB
+	depends on TPM1 || TPM2
+	depends on !VBOOT_RETURN_FROM_VERSTAGE
+	help
+	  Enables measured boot (experimental)
+
+config TPM_MEASURED_BOOT_RUNTIME_DATA
+	string "Runtime data whitelist"
+	default ""
+	depends on TPM_MEASURED_BOOT
+	help
+	  Runtime data whitelist of cbfs filenames. Needs to be a
+	  comma separated list
+
 endmenu # Trusted Platform Module (tpm)
diff --git a/src/security/tpm/Makefile.inc b/src/security/tpm/Makefile.inc
index a2d32cff89..c36183dd9b 100644
--- a/src/security/tpm/Makefile.inc
+++ b/src/security/tpm/Makefile.inc
@@ -6,22 +6,17 @@ ifeq ($(CONFIG_TPM1),y)
 
 ramstage-y += tss/tcg-1.2/tss.c
 romstage-y += tss/tcg-1.2/tss.c
-
-verstage-$(CONFIG_VBOOT) += tss/tcg-1.2/tss.c
-postcar-$(CONFIG_VBOOT) += tss/tcg-1.2/tss.c
+bootblock-y += tss/tcg-1.2/tss.c
+verstage-y += tss/tcg-1.2/tss.c
+postcar-y += tss/tcg-1.2/tss.c
 
 ## TSPI
 
 ramstage-y += tspi/tspi.c
 romstage-y += tspi/tspi.c
-
-verstage-$(CONFIG_VBOOT) += tspi/tspi.c
-postcar-$(CONFIG_VBOOT) += tspi/tspi.c
-
-ramstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-romstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-verstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-postcar-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
+bootblock-y += tspi/tspi.c
+verstage-y += tspi/tspi.c
+postcar-y += tspi/tspi.c
 
 endif # CONFIG_TPM1
 
@@ -39,17 +34,31 @@ verstage-$(CONFIG_VBOOT) += tss/tcg-2.0/tss.c
 postcar-y += tss/tcg-2.0/tss_marshaling.c
 postcar-y += tss/tcg-2.0/tss.c
 
+bootblock-y += tss/tcg-2.0/tss_marshaling.c
+bootblock-y += tss/tcg-2.0/tss.c
+
 ## TSPI
 
 ramstage-y += tspi/tspi.c
 romstage-y += tspi/tspi.c
-
+bootblock-y += tspi/tspi.c
 verstage-$(CONFIG_VBOOT) += tspi/tspi.c
-postcar-$(CONFIG_VBOOT) += tspi/tspi.c
-
-ramstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-romstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-verstage-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
-postcar-$(CONFIG_VBOOT_MEASURED_BOOT) += tspi/log.c
+postcar-y += tspi/tspi.c
 
 endif # CONFIG_TPM2
+
+ifeq ($(CONFIG_TPM_MEASURED_BOOT),y)
+
+bootblock-y += tspi/crtm.c
+verstage-y += tspi/crtm.c
+romstage-y += tspi/crtm.c
+ramstage-y += tspi/crtm.c
+postcar-y += tspi/crtm.c
+
+ramstage-y += tspi/log.c
+romstage-y += tspi/log.c
+verstage-y += tspi/log.c
+postcar-y += tspi/log.c
+bootblock-y += tspi/log.c
+
+endif # CONFIG_TPM_MEASURED_BOOT
diff --git a/src/security/tpm/tspi.h b/src/security/tpm/tspi.h
index 6854401d03..7ea90e280e 100644
--- a/src/security/tpm/tspi.h
+++ b/src/security/tpm/tspi.h
@@ -24,6 +24,12 @@
 #define HASH_DATA_CHUNK_SIZE 1024
 
 /**
+ * Get the pointer to the single instance of global
+ * tcpa log data, and initialize it when necessary
+ */
+struct tcpa_table *tcpa_log_init(void);
+
+/**
  * Clears the pre-RAM tcpa log data and initializes
  * any content with default values
  */
@@ -47,6 +53,7 @@ void tcpa_log_add_table_entry(const char *name, const uint32_t pcr,
  */
 void tcpa_log_dump(void *unused);
 
+
 /**
  * Ask vboot for a digest and extend a TPM PCR with it.
  * @param pcr sets the pcr index
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;
+}
diff --git a/src/security/tpm/tspi/crtm.h b/src/security/tpm/tspi/crtm.h
new file mode 100644
index 0000000000..dfd91e1c0e
--- /dev/null
+++ b/src/security/tpm/tspi/crtm.h
@@ -0,0 +1,65 @@
+/*
+ * 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.
+ */
+
+#ifndef __SECURITY_TSPI_CRTM_H__
+#define __SECURITY_TSPI_CRTM_H__
+
+#include <commonlib/cbfs.h>
+#include <program_loading.h>
+#include <security/tpm/tspi.h>
+#include <types.h>
+
+/* CRTM */
+#define TPM_CRTM_PCR 2
+
+/* PCR for measuring data which changes during runtime
+ * e.g. CMOS, NVRAM...
+ */
+#define TPM_RUNTIME_DATA_PCR 3
+
+/*
+ * Initializes the Core Root of Trust for Measurements
+ * in coreboot. The initial code in a chain of trust must measure
+ * itself.
+ *
+ * Summary:
+ *  + Measures bootblock in CBFS or BOOTBLOCK FMAP partition.
+ *  + If vboot starts in romstage, it measures the romstage
+ *    in CBFS.
+ *  + Measure the verstage if it is compiled as separate
+ *    stage.
+ *
+ * Takes the current vboot context as parameter for s3 checks.
+ * returns on success VB2_SUCCESS, else a vboot error.
+ */
+uint32_t tspi_init_crtm(void);
+
+/**
+ * Measure digests cached in TCPA log entries into PCRs
+ */
+int tspi_measure_cache_to_pcr(void);
+
+#if CONFIG(TPM_MEASURED_BOOT)
+/*
+ * Measures cbfs data via hook (cbfs)
+ * fh is the cbfs file handle to measure
+ * return 0 if successful, else an error
+ */
+uint32_t tspi_measure_cbfs_hook(struct cbfsf *fh, const char *name);
+
+#else
+#define tspi_measure_cbfs_hook(fh, name) 0
+#endif
+
+#endif /* __SECURITY_TSPI_CRTM_H__ */
diff --git a/src/security/tpm/tspi/log.c b/src/security/tpm/tspi/log.c
index 068d78da19..e43f74d069 100644
--- a/src/security/tpm/tspi/log.c
+++ b/src/security/tpm/tspi/log.c
@@ -16,7 +16,7 @@
 #include <security/tpm/tspi.h>
 #include <region_file.h>
 #include <string.h>
-#include <security/vboot/symbols.h>
+#include <symbols.h>
 #include <cbmem.h>
 #include <bootstate.h>
 #include <vb2_sha.h>
@@ -42,7 +42,7 @@ static struct tcpa_table *tcpa_cbmem_init(void)
 	return tclt;
 }
 
-static struct tcpa_table *tcpa_log_init(void)
+struct tcpa_table *tcpa_log_init(void)
 {
 	MAYBE_STATIC_BSS struct tcpa_table *tclt = NULL;
 
@@ -50,12 +50,12 @@ static struct tcpa_table *tcpa_log_init(void)
 	 * If cbmem isn't available use CAR or SRAM */
 	if (!cbmem_possibly_online() &&
 		!CONFIG(VBOOT_RETURN_FROM_VERSTAGE))
-		return (struct tcpa_table *)_vboot2_tpm_log;
+		return (struct tcpa_table *)_tpm_tcpa_log;
 	else if (ENV_ROMSTAGE &&
 		!CONFIG(VBOOT_RETURN_FROM_VERSTAGE)) {
 		tclt = tcpa_cbmem_init();
 		if (!tclt)
-			return (struct tcpa_table *)_vboot2_tpm_log;
+			return (struct tcpa_table *)_tpm_tcpa_log;
 	} else {
 		tclt = tcpa_cbmem_init();
 	}
@@ -128,7 +128,7 @@ void tcpa_log_add_table_entry(const char *name, const uint32_t pcr,
 void tcpa_preram_log_clear(void)
 {
 	printk(BIOS_INFO, "TCPA: Clearing coreboot TCPA log\n");
-	struct tcpa_table *tclt = (struct tcpa_table *)_vboot2_tpm_log;
+	struct tcpa_table *tclt = (struct tcpa_table *)_tpm_tcpa_log;
 	tclt->max_entries = MAX_TCPA_LOG_ENTRIES;
 	tclt->num_entries = 0;
 }
@@ -136,7 +136,7 @@ void tcpa_preram_log_clear(void)
 #if !CONFIG(VBOOT_RETURN_FROM_VERSTAGE)
 static void recover_tcpa_log(int is_recovery)
 {
-	struct tcpa_table *preram_log = (struct tcpa_table *)_vboot2_tpm_log;
+	struct tcpa_table *preram_log = (struct tcpa_table *)_tpm_tcpa_log;
 	struct tcpa_table *ram_log = NULL;
 	int i;
 
diff --git a/src/security/tpm/tspi/tspi.c b/src/security/tpm/tspi/tspi.c
index 0095183ca2..4f0cc972a7 100644
--- a/src/security/tpm/tspi/tspi.c
+++ b/src/security/tpm/tspi/tspi.c
@@ -14,13 +14,14 @@
 
 #include <console/cbmem_console.h>
 #include <console/console.h>
+#include <security/tpm/tspi/crtm.h>
 #include <security/tpm/tspi.h>
 #include <security/tpm/tss.h>
-#if CONFIG(VBOOT)
+#include <assert.h>
+#include <security/vboot/misc.h>
+#include <string.h>
 #include <vb2_api.h>
 #include <vb2_sha.h>
-#include <assert.h>
-#endif
 
 #if CONFIG(TPM1)
 static uint32_t tpm1_invoke_state_machine(void)
@@ -100,6 +101,18 @@ static uint32_t tpm_setup_epilogue(uint32_t result)
 	return result;
 }
 
+static int tpm_is_setup;
+static inline int tspi_tpm_is_setup(void)
+{
+	if (CONFIG(VBOOT))
+		return vboot_logic_executed() || tpm_is_setup;
+
+	if (ENV_RAMSTAGE)
+		return tpm_is_setup;
+
+	return 0;
+}
+
 /*
  * tpm_setup starts the TPM and establishes the root of trust for the
  * anti-rollback mechanism.  tpm_setup can fail for three reasons.  1 A bug.
@@ -170,7 +183,10 @@ uint32_t tpm_setup(int s3flag)
 #if CONFIG(TPM1)
 	result = tpm1_invoke_state_machine();
 #endif
+	if (CONFIG(TPM_MEASURED_BOOT))
+		result = tspi_measure_cache_to_pcr();
 
+	tpm_is_setup = 1;
 	return tpm_setup_epilogue(result);
 }
 
@@ -210,18 +226,27 @@ uint32_t tpm_extend_pcr(int pcr, enum vb2_hash_algorithm digest_algo,
 	if (!digest)
 		return TPM_E_IOERROR;
 
-	result = tlcl_extend(pcr, digest, NULL);
-	if (result != TPM_SUCCESS)
-		return result;
+	if (tspi_tpm_is_setup()) {
+		result = tlcl_lib_init();
+		if (result != TPM_SUCCESS) {
+			printk(BIOS_ERR, "TPM: Can't initialize library.\n");
+			return result;
+		}
+
+		printk(BIOS_DEBUG, "TPM: Extending digest for %s into PCR %d\n", name, pcr);
+		result = tlcl_extend(pcr, digest, NULL);
+		if (result != TPM_SUCCESS)
+			return result;
+	}
 
-	if (CONFIG(VBOOT_MEASURED_BOOT))
+	if (CONFIG(TPM_MEASURED_BOOT))
 		tcpa_log_add_table_entry(name, pcr, digest_algo,
 			digest, digest_len);
 
 	return TPM_SUCCESS;
 }
 
-#if CONFIG(VBOOT)
+#if CONFIG(VBOOT_LIB)
 uint32_t tpm_measure_region(const struct region_device *rdev, uint8_t pcr,
 			    const char *rname)
 {
@@ -234,11 +259,7 @@ uint32_t tpm_measure_region(const struct region_device *rdev, uint8_t pcr,
 
 	if (!rdev || !rname)
 		return TPM_E_INVALID_ARG;
-	result = tlcl_lib_init();
-	if (result != TPM_SUCCESS) {
-		printk(BIOS_ERR, "TPM: Can't initialize library.\n");
-		return result;
-	}
+
 	if (CONFIG(TPM1)) {
 		hash_alg = VB2_HASH_SHA1;
 	} else { /* CONFIG_TPM2 */
@@ -277,7 +298,8 @@ uint32_t tpm_measure_region(const struct region_device *rdev, uint8_t pcr,
 		printk(BIOS_ERR, "TPM: Extending hash into PCR failed.\n");
 		return result;
 	}
-	printk(BIOS_DEBUG, "TPM: Measured %s into PCR %d\n", rname, pcr);
+	printk(BIOS_DEBUG, "TPM: Digest of %s to PCR %d %s\n",
+	       rname, pcr, tspi_tpm_is_setup() ? "measured" : "logged");
 	return TPM_SUCCESS;
 }
-#endif /* VBOOT */
+#endif /* VBOOT_LIB */