1 files changed, 436 insertions, 0 deletions
diff --git a/src/vboot/secdata_tpm.c b/src/vboot/secdata_tpm.c
new file mode 100644
index 0000000000..a51e5d6d55
--- /dev/null
+++ b/src/vboot/secdata_tpm.c
@@ -0,0 +1,436 @@
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Functions for querying, manipulating and locking rollback indices
+ * stored in the TPM NVRAM.
+ */
+
+#include <antirollback.h>
+#include <stdlib.h>
+#include <string.h>
+#include <tpm_lite/tlcl.h>
+#include <vb2_api.h>
+#include <console/console.h>
+
+#ifndef offsetof
+#define offsetof(A,B) __builtin_offsetof(A,B)
+#endif
+
+#ifdef FOR_TEST
+#include <stdio.h>
+#define VBDEBUG(format, args...) printf(format, ## args)
+#else
+#include <console/console.h>
+#define VBDEBUG(format, args...) \
+	printk(BIOS_INFO, "%s():%d: " format,  __func__, __LINE__, ## args)
+#endif
+
+#define RETURN_ON_FAILURE(tpm_cmd) do {				\
+		uint32_t result_;					\
+		if ((result_ = (tpm_cmd)) != TPM_SUCCESS) {		\
+			VBDEBUG("Antirollback: %08x returned by " #tpm_cmd \
+				 "\n", (int)result_);			\
+			return result_;					\
+		}							\
+	} while (0)
+
+
+static uint32_t safe_write(uint32_t index, const void *data, uint32_t length);
+
+uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
+			enum vb2_pcr_digest which_digest)
+{
+	uint8_t buffer[VB2_PCR_DIGEST_RECOMMENDED_SIZE];
+	uint32_t size = sizeof(buffer);
+	int rv;
+
+	rv = vb2api_get_pcr_digest(ctx, which_digest, buffer, &size);
+	if (rv != VB2_SUCCESS)
+		return rv;
+	if (size < TPM_PCR_DIGEST)
+		return VB2_ERROR_UNKNOWN;
+
+	return tlcl_extend(pcr, buffer, NULL);
+}
+
+static uint32_t read_space_firmware(struct vb2_context *ctx)
+{
+	int attempts = 3;
+
+	while (attempts--) {
+		RETURN_ON_FAILURE(tlcl_read(FIRMWARE_NV_INDEX, ctx->secdata,
+		                            VB2_SECDATA_SIZE));
+
+		if (vb2api_secdata_check(ctx) == VB2_SUCCESS)
+			return TPM_SUCCESS;
+
+		VBDEBUG("TPM: %s() - bad CRC\n", __func__);
+	}
+
+	VBDEBUG("TPM: %s() - too many bad CRCs, giving up\n", __func__);
+	return TPM_E_CORRUPTED_STATE;
+}
+
+static uint32_t write_secdata(uint32_t index,
+			      const uint8_t *secdata,
+			      uint32_t len)
+{
+	uint8_t sd[32];
+	uint32_t rv;
+	int attempts = 3;
+
+	if (len > sizeof(sd)) {
+		VBDEBUG("TPM: %s() - data is too large\n", __func__);
+		return TPM_E_WRITE_FAILURE;
+	}
+
+	while (attempts--) {
+		rv = safe_write(index, secdata, len);
+		/* Can't write, not gonna try again */
+		if (rv != TPM_SUCCESS)
+			return rv;
+
+		/* Read it back to be sure it got the right values. */
+		rv = tlcl_read(index, sd, len);
+		if (rv == TPM_SUCCESS && memcmp(secdata, sd, len) == 0)
+			return rv;
+
+		VBDEBUG("TPM: %s() failed. trying again\n", __func__);
+		/* Try writing it again. Maybe it was garbled on the way out. */
+	}
+
+	VBDEBUG("TPM: %s() - too many failures, giving up\n", __func__);
+
+	return TPM_E_CORRUPTED_STATE;
+}
+
+/*
+ * This is derived from rollback_index.h of vboot_reference. see struct
+ * RollbackSpaceKernel for details.
+ */
+static const uint8_t secdata_kernel[] = {
+	0x02,
+	0x4C, 0x57, 0x52, 0x47,
+	0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00,
+	0xE8,
+};
+
+#if IS_ENABLED(CONFIG_TPM2)
+
+/* Nothing special in the TPM2 path yet. */
+static uint32_t safe_write(uint32_t index, const void *data, uint32_t length)
+{
+	return tlcl_write(index, data, length);
+}
+
+static uint32_t set_firmware_space(const void *firmware_blob)
+{
+	RETURN_ON_FAILURE(tlcl_define_space(FIRMWARE_NV_INDEX,
+					    VB2_SECDATA_SIZE));
+	RETURN_ON_FAILURE(safe_write(FIRMWARE_NV_INDEX, firmware_blob,
+				     VB2_SECDATA_SIZE));
+	return TPM_SUCCESS;
+}
+
+static uint32_t set_kernel_space(const void *kernel_blob)
+{
+	RETURN_ON_FAILURE(tlcl_define_space(KERNEL_NV_INDEX,
+					    sizeof(secdata_kernel)));
+	RETURN_ON_FAILURE(safe_write(KERNEL_NV_INDEX, kernel_blob,
+				     sizeof(secdata_kernel)));
+	return TPM_SUCCESS;
+}
+
+static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
+{
+	RETURN_ON_FAILURE(tlcl_force_clear());
+	RETURN_ON_FAILURE(set_firmware_space(ctx->secdata));
+	RETURN_ON_FAILURE(set_kernel_space(secdata_kernel));
+	return TPM_SUCCESS;
+}
+
+uint32_t tpm_clear_and_reenable(void)
+{
+	VBDEBUG("TPM: Clear and re-enable\n");
+	return TPM_SUCCESS;
+}
+
+uint32_t antirollback_lock_space_firmware(void)
+{
+	return tlcl_lock_nv_write(FIRMWARE_NV_INDEX);
+}
+
+#else
+
+uint32_t tpm_clear_and_reenable(void)
+{
+	VBDEBUG("TPM: Clear and re-enable\n");
+	RETURN_ON_FAILURE(tlcl_force_clear());
+	RETURN_ON_FAILURE(tlcl_set_enable());
+	RETURN_ON_FAILURE(tlcl_set_deactivated(0));
+
+	return TPM_SUCCESS;
+}
+
+/**
+ * Like tlcl_write(), but checks for write errors due to hitting the 64-write
+ * limit and clears the TPM when that happens.  This can only happen when the
+ * TPM is unowned, so it is OK to clear it (and we really have no choice).
+ * This is not expected to happen frequently, but it could happen.
+ */
+
+static uint32_t safe_write(uint32_t index, const void *data, uint32_t length)
+{
+	uint32_t result = tlcl_write(index, data, length);
+	if (result == TPM_E_MAXNVWRITES) {
+		RETURN_ON_FAILURE(tpm_clear_and_reenable());
+		return tlcl_write(index, data, length);
+	} else {
+		return result;
+	}
+}
+
+/**
+ * Similarly to safe_write(), this ensures we don't fail a DefineSpace because
+ * we hit the TPM write limit. This is even less likely to happen than with
+ * writes because we only define spaces once at initialization, but we'd
+ * rather be paranoid about this.
+ */
+static uint32_t safe_define_space(uint32_t index, uint32_t perm, uint32_t size)
+{
+	uint32_t result = tlcl_define_space(index, perm, size);
+	if (result == TPM_E_MAXNVWRITES) {
+		RETURN_ON_FAILURE(tpm_clear_and_reenable());
+		return tlcl_define_space(index, perm, size);
+	} else {
+		return result;
+	}
+}
+
+static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
+{
+	TPM_PERMANENT_FLAGS pflags;
+	uint32_t result;
+
+	result = tlcl_get_permanent_flags(&pflags);
+	if (result != TPM_SUCCESS)
+		return result;
+
+	/*
+	 * TPM may come from the factory without physical presence finalized.
+	 * Fix if necessary.
+	 */
+	VBDEBUG("TPM: physicalPresenceLifetimeLock=%d\n",
+		 pflags.physicalPresenceLifetimeLock);
+	if (!pflags.physicalPresenceLifetimeLock) {
+		VBDEBUG("TPM: Finalizing physical presence\n");
+		RETURN_ON_FAILURE(tlcl_finalize_physical_presence());
+	}
+
+	/*
+	 * The TPM will not enforce the NV authorization restrictions until the
+	 * execution of a TPM_NV_DefineSpace with the handle of
+	 * TPM_NV_INDEX_LOCK.  Here we create that space if it doesn't already
+	 * exist. */
+	VBDEBUG("TPM: nvLocked=%d\n", pflags.nvLocked);
+	if (!pflags.nvLocked) {
+		VBDEBUG("TPM: Enabling NV locking\n");
+		RETURN_ON_FAILURE(tlcl_set_nv_locked());
+	}
+
+	/* Clear TPM owner, in case the TPM is already owned for some reason. */
+	VBDEBUG("TPM: Clearing owner\n");
+	RETURN_ON_FAILURE(tpm_clear_and_reenable());
+
+	/* Define the backup space. No need to initialize it, though. */
+	RETURN_ON_FAILURE(safe_define_space(BACKUP_NV_INDEX,
+					    TPM_NV_PER_PPWRITE,
+					    VB2_NVDATA_SIZE));
+
+	/* Define and initialize the kernel space */
+	RETURN_ON_FAILURE(safe_define_space(KERNEL_NV_INDEX,
+					    TPM_NV_PER_PPWRITE,
+					    sizeof(secdata_kernel)));
+	RETURN_ON_FAILURE(write_secdata(KERNEL_NV_INDEX,
+					secdata_kernel,
+					sizeof(secdata_kernel)));
+
+	/* Defines and sets vb2 secdata space */
+	vb2api_secdata_create(ctx);
+	RETURN_ON_FAILURE(safe_define_space(FIRMWARE_NV_INDEX,
+	                                    TPM_NV_PER_GLOBALLOCK |
+	                                    TPM_NV_PER_PPWRITE,
+	                                    VB2_SECDATA_SIZE));
+	RETURN_ON_FAILURE(write_secdata(FIRMWARE_NV_INDEX,
+					ctx->secdata,
+					VB2_SECDATA_SIZE));
+	return TPM_SUCCESS;
+}
+
+uint32_t antirollback_lock_space_firmware(void)
+{
+	return tlcl_set_global_lock();
+}
+#endif
+
+uint32_t factory_initialize_tpm(struct vb2_context *ctx)
+{
+	uint32_t result;
+
+	/* Defines and sets vb2 secdata space */
+	vb2api_secdata_create(ctx);
+
+	VBDEBUG("TPM: factory initialization\n");
+
+	/*
+	 * Do a full test.  This only happens the first time the device is
+	 * turned on in the factory, so performance is not an issue.  This is
+	 * almost certainly not necessary, but it gives us more confidence
+	 * about some code paths below that are difficult to
+	 * test---specifically the ones that set lifetime flags, and are only
+	 * executed once per physical TPM.
+	 */
+	result = tlcl_self_test_full();
+	if (result != TPM_SUCCESS)
+		return result;
+
+	result = _factory_initialize_tpm(ctx);
+	if (result != TPM_SUCCESS)
+		return result;
+
+	VBDEBUG("TPM: factory initialization successful\n");
+
+	return TPM_SUCCESS;
+}
+
+/*
+ * SetupTPM starts the TPM and establishes the root of trust for the
+ * anti-rollback mechanism.  SetupTPM can fail for three reasons.  1 A bug. 2 a
+ * TPM hardware failure. 3 An unexpected TPM state due to some attack.  In
+ * general we cannot easily distinguish the kind of failure, so our strategy is
+ * to reboot in recovery mode in all cases.  The recovery mode calls SetupTPM
+ * again, which executes (almost) the same sequence of operations.  There is a
+ * good chance that, if recovery mode was entered because of a TPM failure, the
+ * failure will repeat itself.  (In general this is impossible to guarantee
+ * because we have no way of creating the exact TPM initial state at the
+ * previous boot.)  In recovery mode, we ignore the failure and continue, thus
+ * giving the recovery kernel a chance to fix things (that's why we don't set
+ * bGlobalLock).  The choice is between a knowingly insecure device and a
+ * bricked device.
+ *
+ * As a side note, observe that we go through considerable hoops to avoid using
+ * the STCLEAR permissions for the index spaces.  We do this to avoid writing
+ * to the TPM flashram at every reboot or wake-up, because of concerns about
+ * the durability of the NVRAM.
+ */
+uint32_t setup_tpm(struct vb2_context *ctx)
+{
+	uint8_t disable;
+	uint8_t deactivated;
+	uint32_t result;
+
+	RETURN_ON_FAILURE(tlcl_lib_init());
+
+	/* Handle special init for S3 resume path */
+	if (ctx->flags & VB2_CONTEXT_S3_RESUME) {
+		result = tlcl_resume();
+		if (result == TPM_E_INVALID_POSTINIT)
+			printk(BIOS_DEBUG, "TPM: Already initialized.\n");
+		return TPM_SUCCESS;
+	}
+
+#ifdef TEGRA_SOFT_REBOOT_WORKAROUND
+	result = tlcl_startup();
+	if (result == TPM_E_INVALID_POSTINIT) {
+		/*
+		 * Some prototype hardware doesn't reset the TPM on a CPU
+		 * reset.  We do a hard reset to get around this.
+		 */
+		VBDEBUG("TPM: soft reset detected\n", result);
+		ctx->flags |= VB2_CONTEXT_SECDATA_WANTS_REBOOT;
+		return TPM_E_MUST_REBOOT;
+	} else if (result != TPM_SUCCESS) {
+		VBDEBUG("TPM: tlcl_startup returned %08x\n", result);
+		return result;
+	}
+#else
+	RETURN_ON_FAILURE(tlcl_startup());
+#endif
+
+	/*
+	 * Some TPMs start the self test automatically at power on. In that case
+	 * we don't need to call ContinueSelfTest. On some (other) TPMs,
+	 * continue_self_test may block. In that case, we definitely don't want
+	 * to call it here. For TPMs in the intersection of these two sets, we
+	 * are screwed. (In other words: TPMs that require manually starting the
+	 * self-test AND block will have poor performance until we split
+	 * tlcl_send_receive() into send() and receive(), and have a state
+	 * machine to control setup.)
+	 *
+	 * This comment is likely to become obsolete in the near future, so
+	 * don't trust it. It may have not been updated.
+	 */
+#ifdef TPM_MANUAL_SELFTEST
+#ifdef TPM_BLOCKING_CONTINUESELFTEST
+#warning "lousy TPM!"
+#endif
+	RETURN_ON_FAILURE(tlcl_continue_self_test());
+#endif
+	result = tlcl_assert_physical_presence();
+	if (result != TPM_SUCCESS) {
+		/*
+		 * It is possible that the TPM was delivered with the physical
+		 * presence command disabled.  This tries enabling it, then
+		 * tries asserting PP again.
+		 */
+		RETURN_ON_FAILURE(tlcl_physical_presence_cmd_enable());
+		RETURN_ON_FAILURE(tlcl_assert_physical_presence());
+	}
+
+	/* Check that the TPM is enabled and activated. */
+	RETURN_ON_FAILURE(tlcl_get_flags(&disable, &deactivated, NULL));
+	if (disable || deactivated) {
+		VBDEBUG("TPM: disabled (%d) or deactivated (%d). Fixing...\n",
+			disable, deactivated);
+		RETURN_ON_FAILURE(tlcl_set_enable());
+		RETURN_ON_FAILURE(tlcl_set_deactivated(0));
+		VBDEBUG("TPM: Must reboot to re-enable\n");
+		ctx->flags |= VB2_CONTEXT_SECDATA_WANTS_REBOOT;
+		return TPM_E_MUST_REBOOT;
+	}
+
+	VBDEBUG("TPM: SetupTPM() succeeded\n");
+	return TPM_SUCCESS;
+}
+
+uint32_t antirollback_read_space_firmware(struct vb2_context *ctx)
+{
+	uint32_t rv;
+
+	rv = setup_tpm(ctx);
+	if (rv)
+		return rv;
+
+	/* Read the firmware space. */
+	rv = read_space_firmware(ctx);
+	if (rv == TPM_E_BADINDEX) {
+		/*
+		 * This seems the first time we've run. Initialize the TPM.
+		 */
+		VBDEBUG("TPM: Not initialized yet.\n");
+		RETURN_ON_FAILURE(factory_initialize_tpm(ctx));
+	} else if (rv != TPM_SUCCESS) {
+		VBDEBUG("TPM: Firmware space in a bad state; giving up.\n");
+		//RETURN_ON_FAILURE(factory_initialize_tpm(ctx));
+		return TPM_E_CORRUPTED_STATE;
+	}
+
+	return TPM_SUCCESS;
+}
+
+uint32_t antirollback_write_space_firmware(struct vb2_context *ctx)
+{
+	return write_secdata(FIRMWARE_NV_INDEX, ctx->secdata, VB2_SECDATA_SIZE);
+}