1 files changed, 438 insertions, 0 deletions
diff --git a/src/security/vboot/vboot_logic.c b/src/security/vboot/vboot_logic.c
new file mode 100644
index 0000000000..e6b97b9c2f
--- /dev/null
+++ b/src/security/vboot/vboot_logic.c
@@ -0,0 +1,438 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google 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 <antirollback.h>
+#include <arch/exception.h>
+#include <assert.h>
+#include <bootmode.h>
+#include <console/console.h>
+#include <console/vtxprintf.h>
+#include <delay.h>
+#include <string.h>
+#include <timestamp.h>
+#include <vb2_api.h>
+#include <security/vboot/misc.h>
+#include <security/vboot/vbnv.h>
+
+/* The max hash size to expect is for SHA512. */
+#define VBOOT_MAX_HASH_SIZE VB2_SHA512_DIGEST_SIZE
+
+#define TODO_BLOCK_SIZE 1024
+
+static int is_slot_a(struct vb2_context *ctx)
+{
+	return !(ctx->flags & VB2_CONTEXT_FW_SLOT_B);
+}
+
+/* exports */
+
+void vb2ex_printf(const char *func, const char *fmt, ...)
+{
+	va_list args;
+
+	if (func)
+		printk(BIOS_INFO, "VB2:%s() ", func);
+
+	va_start(args, fmt);
+	do_printk_va_list(BIOS_INFO, fmt, args);
+	va_end(args);
+
+	return;
+}
+
+int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
+{
+	uint32_t rv;
+	printk(BIOS_INFO, "Clearing TPM owner\n");
+	rv = tpm_clear_and_reenable();
+	if (rv)
+		return VB2_ERROR_EX_TPM_CLEAR_OWNER;
+	return VB2_SUCCESS;
+}
+
+int vb2ex_read_resource(struct vb2_context *ctx,
+			enum vb2_resource_index index,
+			uint32_t offset,
+			void *buf,
+			uint32_t size)
+{
+	struct region_device rdev;
+	const char *name;
+
+	switch (index) {
+	case VB2_RES_GBB:
+		name = "GBB";
+		break;
+	case VB2_RES_FW_VBLOCK:
+		if (is_slot_a(ctx))
+			name = "VBLOCK_A";
+		else
+			name = "VBLOCK_B";
+		break;
+	default:
+		return VB2_ERROR_EX_READ_RESOURCE_INDEX;
+	}
+
+	if (vboot_named_region_device(name, &rdev))
+		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
+
+	if (rdev_readat(&rdev, buf, offset, size) != size)
+		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
+
+	return VB2_SUCCESS;
+}
+
+/* No-op stubs that can be overridden by SoCs with hardware crypto support. */
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_init(enum vb2_hash_algorithm hash_alg,
+			       uint32_t data_size)
+{
+	return VB2_ERROR_EX_HWCRYPTO_UNSUPPORTED;
+}
+
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_extend(const uint8_t *buf, uint32_t size)
+{
+	BUG();	/* Should never get called if init() returned an error. */
+	return VB2_ERROR_UNKNOWN;
+}
+
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_finalize(uint8_t *digest, uint32_t digest_size)
+{
+	BUG();	/* Should never get called if init() returned an error. */
+	return VB2_ERROR_UNKNOWN;
+}
+
+static int handle_digest_result(void *slot_hash, size_t slot_hash_sz)
+{
+	int is_resume;
+
+	/*
+	 * Chrome EC is the only support for vboot_save_hash() &
+	 * vboot_retrieve_hash(), if Chrome EC is not enabled then return.
+	 */
+	if (!IS_ENABLED(CONFIG_EC_GOOGLE_CHROMEEC))
+		return 0;
+
+	/*
+	 * Nothing to do since resuming on the platform doesn't require
+	 * vboot verification again.
+	 */
+	if (!IS_ENABLED(CONFIG_RESUME_PATH_SAME_AS_BOOT))
+		return 0;
+
+	/*
+	 * Assume that if vboot doesn't start in bootblock verified
+	 * RW memory init code is not employed. i.e. memory init code
+	 * lives in RO CBFS.
+	 */
+	if (!IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
+		return 0;
+
+	is_resume = vboot_platform_is_resuming();
+
+	if (is_resume > 0) {
+		uint8_t saved_hash[VBOOT_MAX_HASH_SIZE];
+		const size_t saved_hash_sz = sizeof(saved_hash);
+
+		assert(slot_hash_sz == saved_hash_sz);
+
+		printk(BIOS_DEBUG, "Platform is resuming.\n");
+
+		if (vboot_retrieve_hash(saved_hash, saved_hash_sz)) {
+			printk(BIOS_ERR, "Couldn't retrieve saved hash.\n");
+			return -1;
+		}
+
+		if (memcmp(saved_hash, slot_hash, slot_hash_sz)) {
+			printk(BIOS_ERR, "Hash mismatch on resume.\n");
+			return -1;
+		}
+	} else if (is_resume < 0)
+		printk(BIOS_ERR, "Unable to determine if platform resuming.\n");
+
+	printk(BIOS_DEBUG, "Saving vboot hash.\n");
+
+	/* Always save the hash for the current boot. */
+	if (vboot_save_hash(slot_hash, slot_hash_sz)) {
+		printk(BIOS_ERR, "Error saving vboot hash.\n");
+		/* Though this is an error don't report it up since it could
+		 * lead to a reboot loop. The consequence of this is that
+		 * we will most likely fail resuming because of EC issues or
+		 * the hash digest not matching. */
+		return 0;
+	}
+
+	return 0;
+}
+
+static int hash_body(struct vb2_context *ctx, struct region_device *fw_main)
+{
+	uint64_t load_ts;
+	uint32_t expected_size;
+	uint8_t block[TODO_BLOCK_SIZE];
+	uint8_t hash_digest[VBOOT_MAX_HASH_SIZE];
+	const size_t hash_digest_sz = sizeof(hash_digest);
+	size_t block_size = sizeof(block);
+	size_t offset;
+	int rv;
+
+	/* Clear the full digest so that any hash digests less than the
+	 * max have trailing zeros. */
+	memset(hash_digest, 0, hash_digest_sz);
+
+	/*
+	 * Since loading the firmware and calculating its hash is intertwined,
+	 * we use this little trick to measure them separately and pretend it
+	 * was first loaded and then hashed in one piece with the timestamps.
+	 * (This split won't make sense with memory-mapped media like on x86.)
+	 */
+	load_ts = timestamp_get();
+	timestamp_add(TS_START_HASH_BODY, load_ts);
+
+	expected_size = region_device_sz(fw_main);
+	offset = 0;
+
+	/* Start the body hash */
+	rv = vb2api_init_hash(ctx, VB2_HASH_TAG_FW_BODY, &expected_size);
+	if (rv)
+		return rv;
+
+	/*
+	 * Honor vboot's RW slot size. The expected size is pulled out of
+	 * the preamble and obtained through vb2api_init_hash() above. By
+	 * creating sub region the RW slot portion of the boot media is
+	 * limited.
+	 */
+	if (rdev_chain(fw_main, fw_main, 0, expected_size)) {
+		printk(BIOS_ERR, "Unable to restrict CBFS size.\n");
+		return VB2_ERROR_UNKNOWN;
+	}
+
+	/* Extend over the body */
+	while (expected_size) {
+		uint64_t temp_ts;
+		if (block_size > expected_size)
+			block_size = expected_size;
+
+		temp_ts = timestamp_get();
+		if (rdev_readat(fw_main, block, offset, block_size) < 0)
+			return VB2_ERROR_UNKNOWN;
+		load_ts += timestamp_get() - temp_ts;
+
+		rv = vb2api_extend_hash(ctx, block, block_size);
+		if (rv)
+			return rv;
+
+		expected_size -= block_size;
+		offset += block_size;
+	}
+
+	timestamp_add(TS_DONE_LOADING, load_ts);
+	timestamp_add_now(TS_DONE_HASHING);
+
+	/* Check the result (with RSA signature verification) */
+	rv = vb2api_check_hash_get_digest(ctx, hash_digest, hash_digest_sz);
+	if (rv)
+		return rv;
+
+	timestamp_add_now(TS_END_HASH_BODY);
+
+	if (handle_digest_result(hash_digest, hash_digest_sz))
+		return VB2_ERROR_UNKNOWN;
+
+	return VB2_SUCCESS;
+}
+
+static int locate_firmware(struct vb2_context *ctx,
+				struct region_device *fw_main)
+{
+	const char *name;
+
+	if (is_slot_a(ctx))
+		name = "FW_MAIN_A";
+	else
+		name = "FW_MAIN_B";
+
+	return vboot_named_region_device(name, fw_main);
+}
+
+/**
+ * Save non-volatile and/or secure data if needed.
+ */
+static void save_if_needed(struct vb2_context *ctx)
+{
+	if (ctx->flags & VB2_CONTEXT_NVDATA_CHANGED) {
+		printk(BIOS_INFO, "Saving nvdata\n");
+		save_vbnv(ctx->nvdata);
+		ctx->flags &= ~VB2_CONTEXT_NVDATA_CHANGED;
+	}
+	if (ctx->flags & VB2_CONTEXT_SECDATA_CHANGED) {
+		printk(BIOS_INFO, "Saving secdata\n");
+		antirollback_write_space_firmware(ctx);
+		ctx->flags &= ~VB2_CONTEXT_SECDATA_CHANGED;
+	}
+}
+
+static uint32_t extend_pcrs(struct vb2_context *ctx)
+{
+	return tpm_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
+	       tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
+}
+
+/**
+ * Verify and select the firmware in the RW image
+ *
+ * TODO: Avoid loading a stage twice (once in hash_body & again in load_stage).
+ * when per-stage verification is ready.
+ */
+void verstage_main(void)
+{
+	struct vb2_context ctx;
+	struct region_device fw_main;
+	int rv;
+
+	timestamp_add_now(TS_START_VBOOT);
+
+	/* Set up context and work buffer */
+	vb2_init_work_context(&ctx);
+
+	/* Initialize and read nvdata from non-volatile storage. */
+	vbnv_init(ctx.nvdata);
+
+	/* Set S3 resume flag if vboot should behave differently when selecting
+	 * which slot to boot.  This is only relevant to vboot if the platform
+	 * does verification of memory init and thus must ensure it resumes with
+	 * the same slot that it booted from. */
+	if (IS_ENABLED(CONFIG_RESUME_PATH_SAME_AS_BOOT) &&
+	    IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK) &&
+	    vboot_platform_is_resuming())
+		ctx.flags |= VB2_CONTEXT_S3_RESUME;
+
+	/* Read secdata from TPM. Initialize TPM if secdata not found. We don't
+	 * check the return value here because vb2api_fw_phase1 will catch
+	 * invalid secdata and tell us what to do (=reboot). */
+	timestamp_add_now(TS_START_TPMINIT);
+	antirollback_read_space_firmware(&ctx);
+	timestamp_add_now(TS_END_TPMINIT);
+
+	if (IS_ENABLED(CONFIG_VBOOT_PHYSICAL_DEV_SWITCH) &&
+	    get_developer_mode_switch())
+		ctx.flags |= VB2_CONTEXT_FORCE_DEVELOPER_MODE;
+
+	if (get_recovery_mode_switch()) {
+		ctx.flags |= VB2_CONTEXT_FORCE_RECOVERY_MODE;
+		if (IS_ENABLED(CONFIG_VBOOT_DISABLE_DEV_ON_RECOVERY))
+			ctx.flags |= VB2_DISABLE_DEVELOPER_MODE;
+	}
+
+	if (IS_ENABLED(CONFIG_VBOOT_WIPEOUT_SUPPORTED) &&
+	    get_wipeout_mode_switch())
+		ctx.flags |= VB2_CONTEXT_FORCE_WIPEOUT_MODE;
+
+	if (IS_ENABLED(CONFIG_VBOOT_LID_SWITCH) && !get_lid_switch())
+		ctx.flags |= VB2_CONTEXT_NOFAIL_BOOT;
+
+	/* Do early init (set up secdata and NVRAM, load GBB) */
+	printk(BIOS_INFO, "Phase 1\n");
+	rv = vb2api_fw_phase1(&ctx);
+
+	if (rv) {
+		/*
+		 * If vb2api_fw_phase1 fails, check for return value.
+		 * If it is set to VB2_ERROR_API_PHASE1_RECOVERY, then continue
+		 * into recovery mode.
+		 * For any other error code, save context if needed and reboot.
+		 */
+		if (rv == VB2_ERROR_API_PHASE1_RECOVERY) {
+			printk(BIOS_INFO, "Recovery requested (%x)\n", rv);
+			save_if_needed(&ctx);
+			extend_pcrs(&ctx);	/* ignore failures */
+			timestamp_add_now(TS_END_VBOOT);
+			return;
+		}
+
+		printk(BIOS_INFO, "Reboot reqested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Determine which firmware slot to boot (based on NVRAM) */
+	printk(BIOS_INFO, "Phase 2\n");
+	rv = vb2api_fw_phase2(&ctx);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Try that slot (verify its keyblock and preamble) */
+	printk(BIOS_INFO, "Phase 3\n");
+	timestamp_add_now(TS_START_VERIFY_SLOT);
+	rv = vb2api_fw_phase3(&ctx);
+	timestamp_add_now(TS_END_VERIFY_SLOT);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	printk(BIOS_INFO, "Phase 4\n");
+	rv = locate_firmware(&ctx, &fw_main);
+	if (rv)
+		die("Failed to read FMAP to locate firmware");
+
+	rv = hash_body(&ctx, &fw_main);
+	save_if_needed(&ctx);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		vboot_reboot();
+	}
+
+	rv = extend_pcrs(&ctx);
+	if (rv) {
+		printk(BIOS_WARNING, "Failed to extend TPM PCRs (%#x)\n", rv);
+		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_U_ERROR, rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Lock TPM */
+	rv = antirollback_lock_space_firmware();
+	if (rv) {
+		printk(BIOS_INFO, "Failed to lock TPM (%x)\n", rv);
+		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_L_ERROR, 0);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Lock rec hash space if available. */
+	if (IS_ENABLED(CONFIG_VBOOT_HAS_REC_HASH_SPACE)) {
+		rv = antirollback_lock_space_rec_hash();
+		if (rv) {
+			printk(BIOS_INFO, "Failed to lock rec hash space(%x)\n",
+			       rv);
+			vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_REC_HASH_L_ERROR,
+				    0);
+			save_if_needed(&ctx);
+			vboot_reboot();
+		}
+	}
+
+	printk(BIOS_INFO, "Slot %c is selected\n", is_slot_a(&ctx) ? 'A' : 'B');
+	vb2_set_selected_region(region_device_region(&fw_main));
+	timestamp_add_now(TS_END_VBOOT);
+}