/* Copyright (c) 2012 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. */ /* A lightweight TPM command library. * * The general idea is that TPM commands are array of bytes whose * fields are mostly compile-time constant. The goal is to build much * of the commands at compile time (or build time) and change some of * the fields at run time as needed. The code in * utility/tlcl_generator.c builds structures containing the commands, * as well as the offsets of the fields that need to be set at run * time. */ #include <assert.h> #include <string.h> #include <tpm_lite/tlcl.h> #include <tpm.h> #include <vb2_api.h> #include "tlcl_internal.h" #include "tlcl_structures.h" #ifdef FOR_TEST #include <stdio.h> #define VBDEBUG(format, args...) printf(format, ## args) #else #include <console/console.h> #define VBDEBUG(format, args...) printk(BIOS_DEBUG, format, ## args) #endif static int tpm_send_receive(const uint8_t *request, uint32_t request_length, uint8_t *response, uint32_t *response_length) { size_t len = *response_length; if (tis_sendrecv(request, request_length, response, &len)) return VB2_ERROR_UNKNOWN; /* check 64->32bit overflow and (re)check response buffer overflow */ if (len > *response_length) return VB2_ERROR_UNKNOWN; *response_length = len; return VB2_SUCCESS; } /* Sets the size field of a TPM command. */ static inline void set_tpm_command_size(uint8_t* buffer, uint32_t size) { to_tpm_uint32(buffer + sizeof(uint16_t), size); } /* Gets the size field of a TPM command. */ __attribute__((unused)) static inline int tpm_command_size(const uint8_t* buffer) { uint32_t size; from_tpm_uint32(buffer + sizeof(uint16_t), &size); return (int) size; } /* Gets the code field of a TPM command. */ static inline int tpm_command_code(const uint8_t* buffer) { uint32_t code; from_tpm_uint32(buffer + sizeof(uint16_t) + sizeof(uint32_t), &code); return code; } /* Gets the return code field of a TPM result. */ static inline int tpm_return_code(const uint8_t* buffer) { return tpm_command_code(buffer); } /* Like TlclSendReceive below, but do not retry if NEEDS_SELFTEST or * DOING_SELFTEST errors are returned. */ static uint32_t tlcl_send_receive_no_retry(const uint8_t* request, uint8_t* response, int max_length) { uint32_t response_length = max_length; uint32_t result; result = tpm_send_receive(request, tpm_command_size(request), response, &response_length); if (0 != result) { /* Communication with TPM failed, so response is garbage */ VBDEBUG("TPM: command 0x%x send/receive failed: 0x%x\n", tpm_command_code(request), result); return result; } /* Otherwise, use the result code from the response */ result = tpm_return_code(response); /* TODO: add paranoia about returned response_length vs. max_length * (and possibly expected length from the response header). See * crosbug.com/17017 */ VBDEBUG("TPM: command 0x%x returned 0x%x\n", tpm_command_code(request), result); return result; } /* Sends a TPM command and gets a response. Returns 0 if success or the TPM * error code if error. Waits for the self test to complete if needed. */ uint32_t tlcl_send_receive(const uint8_t* request, uint8_t* response, int max_length) { uint32_t result = tlcl_send_receive_no_retry(request, response, max_length); /* If the command fails because the self test has not completed, try it * again after attempting to ensure that the self test has completed. */ if (result == TPM_E_NEEDS_SELFTEST || result == TPM_E_DOING_SELFTEST) { result = tlcl_continue_self_test(); if (result != TPM_SUCCESS) return result; #if defined(TPM_BLOCKING_CONTINUESELFTEST) || defined(VB_RECOVERY_MODE) /* Retry only once */ result = tlcl_send_receive_no_retry(request, response, max_length); #else /* This needs serious testing. The TPM specification says: "iii. * The caller MUST wait for the actions of TPM_ContinueSelfTest * to complete before reissuing the command C1." But, if * ContinueSelfTest is non-blocking, how do we know that the * actions have completed other than trying again? */ do { result = tlcl_send_receive_no_retry(request, response, max_length); } while (result == TPM_E_DOING_SELFTEST); #endif } return result; } /* Sends a command and returns the error code. */ static uint32_t send(const uint8_t* command) { uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE]; return tlcl_send_receive(command, response, sizeof(response)); } /* Exported functions. */ uint32_t tlcl_lib_init(void) { if (tis_init()) return VB2_ERROR_UNKNOWN; if (tis_open()) return VB2_ERROR_UNKNOWN; return VB2_SUCCESS; } uint32_t tlcl_startup(void) { VBDEBUG("TPM: Startup\n"); return send(tpm_startup_cmd.buffer); } uint32_t tlcl_resume(void) { VBDEBUG("TPM: Resume\n"); return send(tpm_resume_cmd.buffer); } uint32_t tlcl_self_test_full(void) { VBDEBUG("TPM: Self test full\n"); return send(tpm_selftestfull_cmd.buffer); } uint32_t tlcl_continue_self_test(void) { uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE]; VBDEBUG("TPM: Continue self test\n"); /* Call the No Retry version of SendReceive to avoid recursion. */ return tlcl_send_receive_no_retry(tpm_continueselftest_cmd.buffer, response, sizeof(response)); } uint32_t tlcl_define_space(uint32_t index, uint32_t perm, uint32_t size) { struct s_tpm_nv_definespace_cmd cmd; VBDEBUG("TPM: TlclDefineSpace(0x%x, 0x%x, %d)\n", index, perm, size); memcpy(&cmd, &tpm_nv_definespace_cmd, sizeof(cmd)); to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.index, index); to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.perm, perm); to_tpm_uint32(cmd.buffer + tpm_nv_definespace_cmd.size, size); return send(cmd.buffer); } uint32_t tlcl_write(uint32_t index, const void* data, uint32_t length) { struct s_tpm_nv_write_cmd cmd; uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE]; const int total_length = kTpmRequestHeaderLength + kWriteInfoLength + length; VBDEBUG("TPM: tlcl_write(0x%x, %d)\n", index, length); memcpy(&cmd, &tpm_nv_write_cmd, sizeof(cmd)); assert(total_length <= TPM_LARGE_ENOUGH_COMMAND_SIZE); set_tpm_command_size(cmd.buffer, total_length); to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.index, index); to_tpm_uint32(cmd.buffer + tpm_nv_write_cmd.length, length); memcpy(cmd.buffer + tpm_nv_write_cmd.data, data, length); return tlcl_send_receive(cmd.buffer, response, sizeof(response)); } uint32_t tlcl_read(uint32_t index, void* data, uint32_t length) { struct s_tpm_nv_read_cmd cmd; uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE]; uint32_t result_length; uint32_t result; VBDEBUG("TPM: tlcl_read(0x%x, %d)\n", index, length); memcpy(&cmd, &tpm_nv_read_cmd, sizeof(cmd)); to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.index, index); to_tpm_uint32(cmd.buffer + tpm_nv_read_cmd.length, length); result = tlcl_send_receive(cmd.buffer, response, sizeof(response)); if (result == TPM_SUCCESS && length > 0) { uint8_t* nv_read_cursor = response + kTpmResponseHeaderLength; from_tpm_uint32(nv_read_cursor, &result_length); nv_read_cursor += sizeof(uint32_t); memcpy(data, nv_read_cursor, result_length); } return result; } uint32_t tlcl_assert_physical_presence(void) { VBDEBUG("TPM: Asserting physical presence\n"); return send(tpm_ppassert_cmd.buffer); } uint32_t tlcl_physical_presence_cmd_enable(void) { VBDEBUG("TPM: Enable the physical presence command\n"); return send(tpm_ppenable_cmd.buffer); } uint32_t tlcl_finalize_physical_presence(void) { VBDEBUG("TPM: Enable PP cmd, disable HW pp, and set lifetime lock\n"); return send(tpm_finalizepp_cmd.buffer); } uint32_t tlcl_set_nv_locked(void) { VBDEBUG("TPM: Set NV locked\n"); return tlcl_define_space(TPM_NV_INDEX_LOCK, 0, 0); } uint32_t tlcl_force_clear(void) { VBDEBUG("TPM: Force clear\n"); return send(tpm_forceclear_cmd.buffer); } uint32_t tlcl_set_enable(void) { VBDEBUG("TPM: Enabling TPM\n"); return send(tpm_physicalenable_cmd.buffer); } uint32_t tlcl_set_deactivated(uint8_t flag) { struct s_tpm_physicalsetdeactivated_cmd cmd; VBDEBUG("TPM: SetDeactivated(%d)\n", flag); memcpy(&cmd, &tpm_physicalsetdeactivated_cmd, sizeof(cmd)); *(cmd.buffer + cmd.deactivated) = flag; return send(cmd.buffer); } uint32_t tlcl_get_permanent_flags(TPM_PERMANENT_FLAGS* pflags) { uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE]; uint32_t size; uint32_t result = tlcl_send_receive(tpm_getflags_cmd.buffer, response, sizeof(response)); if (result != TPM_SUCCESS) return result; from_tpm_uint32(response + kTpmResponseHeaderLength, &size); assert(size == sizeof(TPM_PERMANENT_FLAGS)); memcpy(pflags, response + kTpmResponseHeaderLength + sizeof(size), sizeof(TPM_PERMANENT_FLAGS)); return result; } uint32_t tlcl_get_flags(uint8_t* disable, uint8_t* deactivated, uint8_t *nvlocked) { TPM_PERMANENT_FLAGS pflags; uint32_t result = tlcl_get_permanent_flags(&pflags); if (result == TPM_SUCCESS) { if (disable) *disable = pflags.disable; if (deactivated) *deactivated = pflags.deactivated; if (nvlocked) *nvlocked = pflags.nvLocked; VBDEBUG("TPM: flags disable=%d, deactivated=%d, nvlocked=%d\n", pflags.disable, pflags.deactivated, pflags.nvLocked); } return result; } uint32_t tlcl_set_global_lock(void) { uint32_t x; VBDEBUG("TPM: Set global lock\n"); return tlcl_write(TPM_NV_INDEX0, (uint8_t*) &x, 0); } uint32_t tlcl_extend(int pcr_num, const uint8_t* in_digest, uint8_t* out_digest) { struct s_tpm_extend_cmd cmd; uint8_t response[kTpmResponseHeaderLength + kPcrDigestLength]; uint32_t result; memcpy(&cmd, &tpm_extend_cmd, sizeof(cmd)); to_tpm_uint32(cmd.buffer + tpm_extend_cmd.pcrNum, pcr_num); memcpy(cmd.buffer + cmd.inDigest, in_digest, kPcrDigestLength); result = tlcl_send_receive(cmd.buffer, response, sizeof(response)); if (result != TPM_SUCCESS) return result; if (out_digest) memcpy(out_digest, response + kTpmResponseHeaderLength, kPcrDigestLength); return result; }