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-rw-r--r--src/security/vboot/Makefile.inc2
-rw-r--r--src/security/vboot/mrc_cache_hash_tpm.c115
2 files changed, 117 insertions, 0 deletions
diff --git a/src/security/vboot/Makefile.inc b/src/security/vboot/Makefile.inc
index 75c2a9e44c..b542425346 100644
--- a/src/security/vboot/Makefile.inc
+++ b/src/security/vboot/Makefile.inc
@@ -78,6 +78,8 @@ romstage-y += vboot_handoff.c common.c
ramstage-y += common.c
postcar-y += common.c
+romstage-$(CONFIG_FSP2_0_USES_TPM_MRC_HASH) += mrc_cache_hash_tpm.c
+
ifeq ($(CONFIG_VBOOT_SEPARATE_VERSTAGE),y)
VB_FIRMWARE_ARCH := $(ARCHDIR-$(ARCH-verstage-y))
else
diff --git a/src/security/vboot/mrc_cache_hash_tpm.c b/src/security/vboot/mrc_cache_hash_tpm.c
new file mode 100644
index 0000000000..d54f8f4618
--- /dev/null
+++ b/src/security/vboot/mrc_cache_hash_tpm.c
@@ -0,0 +1,115 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Facebook Inc
+ * Copyright (C) 2015-2016 Intel Corp.
+ * (Written by Andrey Petrov <andrey.petrov@intel.com> for Intel Corp.)
+ * (Written by Alexandru Gagniuc <alexandrux.gagniuc@intel.com> for Intel Corp.)
+ *
+ * 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 <security/vboot/antirollback.h>
+#include <program_loading.h>
+#include <security/vboot/vboot_common.h>
+#include <vb2_api.h>
+#include <security/tpm/tss.h>
+#include <fsp/memory_init.h>
+#include <console/console.h>
+#include <string.h>
+
+void mrc_cache_update_hash(const uint8_t *data, size_t size)
+{
+ uint8_t data_hash[VB2_SHA256_DIGEST_SIZE];
+ static const uint8_t dead_hash[VB2_SHA256_DIGEST_SIZE] = {
+ 0xba, 0xad, 0xda, 0x1a, /* BAADDA1A */
+ 0xde, 0xad, 0xde, 0xad, /* DEADDEAD */
+ 0xde, 0xad, 0xda, 0x1a, /* DEADDA1A */
+ 0xba, 0xad, 0xba, 0xad, /* BAADBAAD */
+ 0xba, 0xad, 0xda, 0x1a, /* BAADDA1A */
+ 0xde, 0xad, 0xde, 0xad, /* DEADDEAD */
+ 0xde, 0xad, 0xda, 0x1a, /* DEADDA1A */
+ 0xba, 0xad, 0xba, 0xad, /* BAADBAAD */
+ };
+ const uint8_t *hash_ptr = data_hash;
+
+ /* We do not store normal mode data hash in TPM. */
+ if (!vboot_recovery_mode_enabled())
+ return;
+
+ /* Initialize TPM driver. */
+ if (tlcl_lib_init() != VB2_SUCCESS) {
+ printk(BIOS_ERR, "MRC: TPM driver initialization failed.\n");
+ return;
+ }
+
+ /* Calculate hash of data generated by MRC. */
+ if (vb2_digest_buffer(data, size, VB2_HASH_SHA256, data_hash,
+ sizeof(data_hash))) {
+ printk(BIOS_ERR, "MRC: SHA-256 calculation failed for data. "
+ "Not updating TPM hash space.\n");
+ /*
+ * Since data is being updated in recovery cache, the hash
+ * currently stored in TPM recovery hash space is no longer
+ * valid. If we are not able to calculate hash of the data being
+ * updated, reset all the bits in TPM recovery hash space to
+ * pre-defined hash pattern.
+ */
+ hash_ptr = dead_hash;
+ }
+
+ /* Write hash of data to TPM space. */
+ if (antirollback_write_space_rec_hash(hash_ptr, VB2_SHA256_DIGEST_SIZE)
+ != TPM_SUCCESS) {
+ printk(BIOS_ERR, "MRC: Could not save hash to TPM.\n");
+ return;
+ }
+
+ printk(BIOS_INFO, "MRC: TPM MRC hash updated successfully.\n");
+}
+
+int mrc_cache_verify_hash(const uint8_t *data, size_t size)
+{
+ uint8_t data_hash[VB2_SHA256_DIGEST_SIZE];
+ uint8_t tpm_hash[VB2_SHA256_DIGEST_SIZE];
+
+ /* We do not store normal mode data hash in TPM. */
+ if (!vboot_recovery_mode_enabled())
+ return 1;
+
+ /* Calculate hash of data read from RECOVERY_MRC_CACHE. */
+ if (vb2_digest_buffer(data, size, VB2_HASH_SHA256, data_hash,
+ sizeof(data_hash))) {
+ printk(BIOS_ERR, "MRC: SHA-256 calculation failed for data.\n");
+ return 0;
+ }
+
+ /* Initialize TPM driver. */
+ if (tlcl_lib_init() != VB2_SUCCESS) {
+ printk(BIOS_ERR, "MRC: TPM driver initialization failed.\n");
+ return 0;
+ }
+
+ /* Read hash of MRC data saved in TPM. */
+ if (antirollback_read_space_rec_hash(tpm_hash, sizeof(tpm_hash))
+ != TPM_SUCCESS) {
+ printk(BIOS_ERR, "MRC: Could not read hash from TPM.\n");
+ return 0;
+ }
+
+ if (memcmp(tpm_hash, data_hash, sizeof(tpm_hash))) {
+ printk(BIOS_ERR, "MRC: Hash comparison failed.\n");
+ return 0;
+ }
+
+ printk(BIOS_INFO, "MRC: Hash comparison successful. "
+ "Using data from RECOVERY_MRC_CACHE\n");
+ return 1;
+}