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Diffstat (limited to 'src/security/vboot/vboot_logic.c')
-rw-r--r--src/security/vboot/vboot_logic.c438
1 files changed, 438 insertions, 0 deletions
diff --git a/src/security/vboot/vboot_logic.c b/src/security/vboot/vboot_logic.c
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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);
+}