firmware/lib/tpm2_lite/tlcl.c

/* Copyright 2016 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.
 *
 * Some TPM constants and type definitions for standalone compilation for use
 * in the firmware
 */

#include "2common.h"
#include "2sysincludes.h"
#include "tlcl.h"
#include "tpm2_marshaling.h"

/*
 * TODO(chromium:1032930): Originally accessed by including secdata_tpm.h.
 * This file moved to depthcharge, and vboot shouldn't need to know the indices
 * of different TPM spaces anyways.  But since the vboot TPM 2.0 implementation
 * uses TPM 1.2 primitives as its API, TlclSetGlobalLock (TPM 1.2) needs to use
 * the firmware space index to emulate a TlclWriteLock call (TPM 2.0).
 */
#define FIRMWARE_NV_INDEX 0x1007

/* Global buffer for deserialized responses. */
struct tpm2_response tpm2_resp;

/*
 * Serializes and sends the command, gets back the response and
 * parses it into the provided buffer.
 *
 * @command: command code.
 * @command_body: command-specific payload.
 * @response: pointer to the buffer to place the parsed response to.
 *
 * Returns the result of processing the command:
 *   - if an error happened at marshaling, sending, receiving or unmarshaling
 *     stages, returns the error code;
 *   - if the received response was successfully unmarshaled, returns success
 *     regardless of the received response code.
 */
static uint32_t tpm_get_response(TPM_CC command,
				 void *command_body,
				 struct tpm2_response *response)
{
	/* Command/response buffer. */
	static uint8_t cr_buffer[TPM_BUFFER_SIZE];
	int out_size;
	uint32_t res;
	uint32_t in_size;

	out_size = tpm_marshal_command(command, command_body,
				       cr_buffer, sizeof(cr_buffer));
	if (out_size < 0) {
		VB2_DEBUG("command %#x, failed to serialize\n", command);
		return TPM_E_WRITE_FAILURE;
	}

	in_size = sizeof(cr_buffer);
	res = vb2ex_tpm_send_recv(cr_buffer, out_size, cr_buffer, &in_size);
	if (res != TPM_SUCCESS) {
		VB2_DEBUG("tpm transaction failed for %#x with error %#x\n",
			  command, res);
		return res;
	}

	if (tpm_unmarshal_response(command, cr_buffer, in_size, response) < 0) {
		VB2_DEBUG("command %#x, failed to parse response\n", command);
		return TPM_E_READ_FAILURE;
	}

	VB2_DEBUG("command %#x, return code %#x\n", command,
		  response->hdr.tpm_code);

	return TPM_SUCCESS;
}

/*
 * Same as tpm_get_response() but, if the response was successfully received,
 * returns the received response code. The set of errors returned by the
 * communication stack doesn't overlap with the set of errors returned by the
 * TPM, so it's always possible to distinguish the two. In case of communication
 * errors, the caller should not check other fields of response, as the response
 * is likely not filled. In any case, it is recommended that callers, who need
 * to work with response fields even if a non-zero response code was received
 * from the TPM, use tpm_get_response() and explicitly check the response code
 * themselves.
 */
static uint32_t tpm_send_receive(TPM_CC command,
				 void *command_body,
				 struct tpm2_response *response)
{
	uint32_t rv = tpm_get_response(command, command_body, response);

	return rv ? rv : response->hdr.tpm_code;
}

/*
 * Same as tpm_send_receive() for callers that care only about the return code.
 */
static uint32_t tpm_get_response_code(TPM_CC command, void *command_body)
{
	return tpm_send_receive(command, command_body, &tpm2_resp);
}

static uint32_t tlcl_read_ph_disabled(void)
{
	uint32_t rv;
	TPM_STCLEAR_FLAGS flags;

	rv = TlclGetSTClearFlags(&flags);
	if (rv == TPM_SUCCESS)
		tpm_set_ph_disabled(!flags.phEnable);

	return rv;
}

uint32_t TlclLibInit(void)
{
	uint32_t rv;

	rv = vb2ex_tpm_init();
	if (rv != TPM_SUCCESS)
		return rv;

	rv = tlcl_read_ph_disabled();
	if (rv != TPM_SUCCESS)
		TlclLibClose();

	return rv;
}

uint32_t TlclLibClose(void)
{
	return vb2ex_tpm_close();
}

uint32_t TlclSendReceive(const uint8_t *request, uint8_t *response,
			 int max_length)
{
	uint32_t rv, resp_size;

	resp_size = max_length;
	rv = vb2ex_tpm_send_recv(request, tpm_get_packet_size(request),
				 response, &resp_size);

	return rv ? rv : tpm_get_packet_response_code(response);
}

int TlclPacketSize(const uint8_t *packet)
{
	return tpm_get_packet_size(packet);
}

uint32_t TlclStartup(void)
{
	struct tpm2_startup_cmd startup;

	startup.startup_type = TPM_SU_CLEAR;

	return tpm_get_response_code(TPM2_Startup, &startup);
}

uint32_t TlclSaveState(void)
{
	struct tpm2_shutdown_cmd shutdown;

	shutdown.shutdown_type = TPM_SU_STATE;

	return tpm_get_response_code(TPM2_Shutdown, &shutdown);
}

uint32_t TlclResume(void)
{
	struct tpm2_startup_cmd startup;

	startup.startup_type = TPM_SU_STATE;

	return tpm_get_response_code(TPM2_Startup, &startup);
}

uint32_t TlclSelfTestFull(void)
{
	struct tpm2_self_test_cmd self_test;

	self_test.full_test = 1;

	return tpm_get_response_code(TPM2_SelfTest, &self_test);
}

uint32_t TlclContinueSelfTest(void)
{
	struct tpm2_self_test_cmd self_test;

	self_test.full_test = 0;

	return tpm_get_response_code(TPM2_SelfTest, &self_test);
}

uint32_t TlclDefineSpace(uint32_t index, uint32_t perm, uint32_t size)
{
	return TlclDefineSpaceEx(NULL, 0, index, perm, size, NULL, 0);
}

#ifdef CHROMEOS_ENVIRONMENT

uint32_t TlclUndefineSpace(uint32_t index)
{
	return TlclUndefineSpaceEx(NULL, 0, index);
}

uint32_t TlclUndefineSpaceEx(const uint8_t* owner_auth,
			     uint32_t owner_auth_size,
			     uint32_t index)
{
	struct tpm2_nv_undefine_space_cmd undefine_space;
	uint32_t permissions;
	uint32_t rv;

	/* Authentication support is not implemented. */
	VB2_ASSERT(owner_auth == NULL && owner_auth_size == 0);

	/* get the publicInfo of index */
	rv = TlclGetPermissions(index, &permissions);
	if (rv != TPM_SUCCESS) {
		return rv;
	}
	undefine_space.nvIndex = HR_NV_INDEX + index;
	undefine_space.use_platform_auth =
		(permissions & TPMA_NV_PLATFORMCREATE) > 0;
	return tpm_get_response_code(TPM2_NV_UndefineSpace, &undefine_space);
}

#endif  /* CHROMEOS_ENVIRONMENT */

uint32_t TlclDefineSpaceEx(const uint8_t* owner_auth, uint32_t owner_auth_size,
			   uint32_t index, uint32_t perm, uint32_t size,
			   const void* auth_policy, uint32_t auth_policy_size)
{
	struct tpm2_nv_define_space_cmd define_space;

	/* Authentication support is not implemented. */
	VB2_ASSERT(owner_auth == NULL && owner_auth_size == 0);

	/* For backwards-compatibility, if no READ or WRITE permissions are set,
	 * assume readable/writeable with empty auth value.
	 */
	if (!(perm & TPMA_NV_MASK_WRITE))
		perm |= TPMA_NV_AUTHWRITE;
	if (!(perm & TPMA_NV_MASK_READ))
		perm |= TPMA_NV_AUTHREAD;

	memset(&define_space, 0, sizeof(define_space));
	define_space.publicInfo.nvIndex = HR_NV_INDEX + index;
	define_space.publicInfo.dataSize = size;
	define_space.publicInfo.attributes = perm;
	define_space.publicInfo.nameAlg = TPM_ALG_SHA256;
	if (auth_policy && auth_policy_size > 0) {
		define_space.publicInfo.authPolicy.size = auth_policy_size;
		define_space.publicInfo.authPolicy.buffer =
				(uint8_t*) auth_policy;
	}

	return tpm_get_response_code(TPM2_NV_DefineSpace, &define_space);
}

uint32_t TlclInitNvAuthPolicy(uint32_t pcr_selection_bitmap,
			      const uint8_t pcr_values[][TPM_PCR_DIGEST],
			      void* auth_policy, uint32_t* auth_policy_size)
{
	/* Actual PCR selection isn't implemented. */
	VB2_ASSERT(pcr_selection_bitmap == 0);
	*auth_policy_size = 0;
	return TPM_SUCCESS;
}

/**
 * Issue a ForceClear.  The TPM error code is returned.
 */
uint32_t TlclForceClear(void)
{
	return tpm_get_response_code(TPM2_Clear, NULL);
}

uint32_t TlclSetDeactivated(uint8_t flag)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return TPM_SUCCESS;
}

uint32_t TlclSetEnable(void)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return TPM_SUCCESS;
}

uint32_t TlclGetFlags(uint8_t* disable,
		      uint8_t* deactivated,
		      uint8_t *nvlocked)
{
	/* For TPM2 the flags are always the same */
	if (disable)
		*disable = 0;
	if (deactivated)
		*deactivated = 0;
	if (nvlocked)
		*nvlocked = 1;
	return TPM_SUCCESS;
}

int TlclIsOwned(void)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return 0;
}

uint32_t TlclExtend(int pcr_num, const uint8_t *in_digest, uint8_t *out_digest)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return TPM_SUCCESS;
}


static uint32_t tlcl_nv_read_public(uint32_t index,
				    struct nv_read_public_response **presp)
{
	struct tpm2_response *response = &tpm2_resp;
	struct tpm2_nv_read_public_cmd read_pub;
	uint32_t rv;

	memset(&read_pub, 0, sizeof(read_pub));
	read_pub.nvIndex = HR_NV_INDEX + index;

	rv = tpm_send_receive(TPM2_NV_ReadPublic, &read_pub, response);
	if (rv == TPM_SUCCESS)
		*presp = &response->nv_read_public;

	return rv;
}

/**
 * Get the permission bits for the NVRAM space with |index|.
 */
uint32_t TlclGetPermissions(uint32_t index, uint32_t *permissions)
{
	uint32_t rv;
	struct nv_read_public_response *resp;

	rv = tlcl_nv_read_public(index, &resp);
	if (rv == TPM_SUCCESS)
		*permissions = resp->nvPublic.attributes;

	return rv;
}

uint32_t TlclGetSpaceInfo(uint32_t index, uint32_t *attributes, uint32_t *size,
			  void* auth_policy, uint32_t* auth_policy_size)
{
	uint32_t rv;
	struct nv_read_public_response *resp;

	rv = tlcl_nv_read_public(index, &resp);
	if (rv != TPM_SUCCESS)
		return rv;

	*attributes = resp->nvPublic.attributes;
	*size = resp->nvPublic.dataSize;
	if (resp->nvPublic.authPolicy.size > *auth_policy_size) {
		return TPM_E_BUFFER_SIZE;
	}

	*auth_policy_size = resp->nvPublic.authPolicy.size;
	memcpy(auth_policy, resp->nvPublic.authPolicy.buffer,
	       *auth_policy_size);

	return TPM_SUCCESS;
}

static uint32_t tlcl_get_capability(TPM_CAP cap, TPM_PT property,
				    struct get_capability_response **presp)
{
	struct tpm2_response *response = &tpm2_resp;
	struct tpm2_get_capability_cmd getcap;
	uint32_t rv;

	getcap.capability = cap;
	getcap.property = property;
	getcap.property_count = 1;

	rv = tpm_send_receive(TPM2_GetCapability, &getcap, response);
	if (rv == TPM_SUCCESS)
		*presp = &response->cap;

	return rv;
}

static uint32_t tlcl_get_tpm_property(TPM_PT property, uint32_t *pvalue)
{
	uint32_t rv;
	struct get_capability_response *resp;
	TPML_TAGGED_TPM_PROPERTY *tpm_prop;

	rv = tlcl_get_capability(TPM_CAP_TPM_PROPERTIES, property, &resp);
	if (rv != TPM_SUCCESS)
		return rv;

	if (resp->capability_data.capability != TPM_CAP_TPM_PROPERTIES)
		return TPM_E_IOERROR;

	tpm_prop = &resp->capability_data.data.tpm_properties;

	if ((tpm_prop->count != 1) ||
	    (tpm_prop->tpm_property[0].property != property))
		return TPM_E_IOERROR;

	*pvalue = tpm_prop->tpm_property[0].value;
	return TPM_SUCCESS;
}

uint32_t TlclGetPermanentFlags(TPM_PERMANENT_FLAGS *pflags)
{
	return tlcl_get_tpm_property(TPM_PT_PERMANENT,
				     (uint32_t *)pflags);
}

uint32_t TlclGetSTClearFlags(TPM_STCLEAR_FLAGS *pflags)
{
	return tlcl_get_tpm_property(TPM_PT_STARTUP_CLEAR,
				     (uint32_t *)pflags);
}

uint32_t TlclGetOwnership(uint8_t *owned)
{
	uint32_t rv;
	TPM_PERMANENT_FLAGS flags;
	*owned = 0;

	rv = TlclGetPermanentFlags(&flags);
	if (rv == TPM_SUCCESS)
		*owned = flags.ownerAuthSet;

	return rv;
}

static uint32_t tlcl_lock_nv_write(uint32_t index)
{
	struct tpm2_nv_write_lock_cmd nv_wl;

	nv_wl.nvIndex = HR_NV_INDEX + index;
	return tpm_get_response_code(TPM2_NV_WriteLock, &nv_wl);
}

static uint32_t tlcl_disable_platform_hierarchy(void)
{
	struct tpm2_hierarchy_control_cmd hc;
	uint32_t rv;

	hc.enable = TPM_RH_PLATFORM;
	hc.state = 0;

	rv = tpm_get_response_code(TPM2_Hierarchy_Control, &hc);
	if (rv == TPM_SUCCESS)
		tpm_set_ph_disabled(1);

	return rv;
}

/**
 * The name of the function was kept to maintain the existing TPM API, but
 * TPM2.0 does not use the global lock to protect the FW rollback counter.
 * Instead it calls WriteLock for the FW NVRAM index to prevent future
 * writes to it.
 *
 * It first checks if the platform hierarchy is already disabled, and does
 * nothing, if so. Otherwise, WriteLock for the index obviously fails.
 */
uint32_t TlclSetGlobalLock(void)
{
	if (tpm_is_ph_disabled())
		return TPM_SUCCESS;
	else
		return tlcl_lock_nv_write(FIRMWARE_NV_INDEX);
}

/**
 * Turn off physical presence and locks it off until next reboot.  The TPM
 * error code is returned.
 *
 * The name of the function was kept to maintain the existing TPM API, but
 * TPM2.0 does not have to use the Physical Presence concept. Instead it just
 * removes platform authorization - this makes sure that firmware and kernel
 * rollback counter spaces can not be modified.
 *
 * It also explicitly locks the kernel rollback counter space (the FW rollback
 * counter space was locked before RW firmware started.)
 */
uint32_t TlclLockPhysicalPresence(void)
{
	if (tpm_is_ph_disabled())
		return TPM_SUCCESS;

	return tlcl_disable_platform_hierarchy();
}

uint32_t TlclRead(uint32_t index, void* data, uint32_t length)
{
	struct tpm2_nv_read_cmd nv_readc;
	struct tpm2_response *response = &tpm2_resp;
	uint32_t rv;

	memset(&nv_readc, 0, sizeof(nv_readc));

	nv_readc.nvIndex = HR_NV_INDEX + index;
	nv_readc.size = length;

	rv = tpm_send_receive(TPM2_NV_Read, &nv_readc, response);

	/* Need to map tpm error codes into internal values. */
	switch (rv) {
	case TPM_SUCCESS:
		break;

	case 0x28b:
		return TPM_E_BADINDEX;

	default:
		return rv;
	}

	if (length > response->nvr.buffer.t.size)
		return TPM_E_RESPONSE_TOO_LARGE;

	if (length < response->nvr.buffer.t.size)
		return TPM_E_READ_EMPTY;

	memcpy(data, response->nvr.buffer.t.buffer, length);

	return TPM_SUCCESS;
}

uint32_t TlclWrite(uint32_t index, const void *data, uint32_t length)
{
	struct tpm2_nv_write_cmd nv_writec;

	memset(&nv_writec, 0, sizeof(nv_writec));

	nv_writec.nvIndex = HR_NV_INDEX + index;
	nv_writec.data.t.size = length;
	nv_writec.data.t.buffer = data;

	return tpm_get_response_code(TPM2_NV_Write, &nv_writec);
}

uint32_t TlclPCRRead(uint32_t index, void *data, uint32_t length)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return TPM_SUCCESS;
}

uint32_t TlclWriteLock(uint32_t index)
{
	struct tpm2_nv_write_lock_cmd nv_writelockc;

	memset(&nv_writelockc, 0, sizeof(nv_writelockc));

	nv_writelockc.nvIndex = HR_NV_INDEX | index;

	return tpm_get_response_code(TPM2_NV_WriteLock, &nv_writelockc);
}

uint32_t TlclReadLock(uint32_t index)
{
	struct tpm2_nv_read_lock_cmd nv_readlockc;

	memset(&nv_readlockc, 0, sizeof(nv_readlockc));

	nv_readlockc.nvIndex = HR_NV_INDEX | index;

	return tpm_get_response_code(TPM2_NV_ReadLock, &nv_readlockc);
}

uint32_t TlclGetRandom(uint8_t *data, uint32_t length, uint32_t *size)
{
	uint32_t rv;
	struct tpm2_get_random_cmd random;
	struct get_random_response *response = &tpm2_resp.random;
	size_t max_len, offset;

	offset = offsetof(struct tpm2_response, random.random_bytes.buffer);
	max_len = TPM_BUFFER_SIZE - offset;

	if (length > max_len)
		return TPM_E_BUFFER_SIZE;

	random.bytes_requested = length;

	rv = tpm_send_receive(TPM2_GetRandom, &random, &tpm2_resp);
	if (rv != TPM_SUCCESS)
		return rv;

	*size = response->random_bytes.size;
	if (*size > length)
		return TPM_E_RESPONSE_TOO_LARGE;

	memcpy(data, response->random_bytes.buffer, *size);

	return rv;
}

// Converts TPM_PT_VENDOR_STRING_x |value| to an array of bytes in |buf|.
// Returns the number of bytes in the array.
// |buf| should be at least 4 bytes long.
static size_t tlcl_vendor_string_parse(uint32_t value, uint8_t* buf)
{
	size_t len = 0;
	int shift = 24;
	for (; len < 4; shift -= 8) {
		uint8_t byte = (value >> shift) & 0xffu;
		if (!byte)
			break;
		buf[len++] = byte;
	}
	return len;
}

uint32_t TlclGetVersion(uint32_t* vendor, uint64_t* firmware_version,
			uint8_t* vendor_specific_buf,
			size_t* vendor_specific_buf_size)
{
	uint32_t result =  tlcl_get_tpm_property(TPM_PT_MANUFACTURER, vendor);
	if (result != TPM_SUCCESS)
		return result;

	uint32_t version_1;
	uint32_t version_2;
	result = tlcl_get_tpm_property(TPM_PT_FIRMWARE_VERSION_1, &version_1);
	if (result != TPM_SUCCESS)
		return result;
	result = tlcl_get_tpm_property(TPM_PT_FIRMWARE_VERSION_2, &version_2);
	if (result != TPM_SUCCESS)
		return result;

	*firmware_version = ((uint64_t) version_1 << 32) | version_2;

	if (!vendor_specific_buf_size)
		return TPM_SUCCESS;

	size_t total_size = 0;
	uint32_t prop_id;
	uint8_t prop_string[16];
	for (prop_id = TPM_PT_VENDOR_STRING_1;
	     prop_id <= TPM_PT_VENDOR_STRING_4;
	     ++prop_id) {
		uint32_t prop_value;
		result = tlcl_get_tpm_property(prop_id, &prop_value);
		if (result != TPM_SUCCESS)
			break;

		size_t prop_len = tlcl_vendor_string_parse(
				prop_value, prop_string + total_size);
		VB2_ASSERT(prop_len <= 4 &&
			   total_size + prop_len <= sizeof(prop_string));
		total_size += prop_len;
		if (prop_len < 4)
			break;
	}
	if (vendor_specific_buf) {
		if (total_size > *vendor_specific_buf_size)
			total_size = *vendor_specific_buf_size;
		memcpy(vendor_specific_buf, prop_string, total_size);
	}
	*vendor_specific_buf_size = total_size;
	return TPM_SUCCESS;
}

uint32_t TlclIFXFieldUpgradeInfo(TPM_IFX_FIELDUPGRADEINFO* info)
{
	VB2_DEBUG("NOT YET IMPLEMENTED\n");
	return TPM_E_IOERROR;
}