/* Microsoft Reference Implementation for TPM 2.0 * * The copyright in this software is being made available under the BSD License, * included below. This software may be subject to other third party and * contributor rights, including patent rights, and no such rights are granted * under this license. * * Copyright (c) Microsoft Corporation * * All rights reserved. * * BSD License * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this list * of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, this * list of conditions and the following disclaimer in the documentation and/or * other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ""AS IS"" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ //** Introduction // // This file contains the entry function ExecuteCommand() which provides the main // control flow for TPM command execution. //** Includes #include "Tpm.h" #include "ExecCommand_fp.h" // Uncomment this next #include if doing static command/response buffer sizing // #include "CommandResponseSizes_fp.h" //** ExecuteCommand() // // The function performs the following steps. // // a) Parses the command header from input buffer. // b) Calls ParseHandleBuffer() to parse the handle area of the command. // c) Validates that each of the handles references a loaded entity. // d) Calls ParseSessionBuffer () to: // 1) unmarshal and parse the session area; // 2) check the authorizations; and // 3) when necessary, decrypt a parameter. // e) Calls CommandDispatcher() to: // 1) unmarshal the command parameters from the command buffer; // 2) call the routine that performs the command actions; and // 3) marshal the responses into the response buffer. // f) If any error occurs in any of the steps above create the error response // and return. // g) Calls BuildResponseSession() to: // 1) when necessary, encrypt a parameter // 2) build the response authorization sessions // 3) update the audit sessions and nonces // h) Calls BuildResponseHeader() to complete the construction of the response. // // 'responseSize' is set by the caller to the maximum number of bytes available in // the output buffer. ExecuteCommand will adjust the value and return the number // of bytes placed in the buffer. // // 'response' is also set by the caller to indicate the buffer into which // ExecuteCommand is to place the response. // // 'request' and 'response' may point to the same buffer // // Note: As of February, 2016, the failure processing has been moved to the // platform-specific code. When the TPM code encounters an unrecoverable failure, it // will SET g_inFailureMode and call _plat__Fail(). That function should not return // but may call ExecuteCommand(). // LIB_EXPORT void ExecuteCommand( uint32_t requestSize, // IN: command buffer size unsigned char *request, // IN: command buffer uint32_t *responseSize, // IN/OUT: response buffer size unsigned char **response // IN/OUT: response buffer ) { // Command local variables UINT32 commandSize; COMMAND command; // Response local variables UINT32 maxResponse = *responseSize; TPM_RC result; // return code for the command // This next function call is used in development to size the command and response // buffers. The values printed are the sizes of the internal structures and // not the sizes of the canonical forms of the command response structures. Also, // the sizes do not include the tag, command.code, requestSize, or the authorization // fields. //CommandResponseSizes(); // Set flags for NV access state. This should happen before any other // operation that may require a NV write. Note, that this needs to be done // even when in failure mode. Otherwise, g_updateNV would stay SET while in // Failure mode and the NV would be written on each call. g_updateNV = UT_NONE; g_clearOrderly = FALSE; if(g_inFailureMode) { // Do failure mode processing TpmFailureMode(requestSize, request, responseSize, response); return; } // Query platform to get the NV state. The result state is saved internally // and will be reported by NvIsAvailable(). The reference code requires that // accessibility of NV does not change during the execution of a command. // Specifically, if NV is available when the command execution starts and then // is not available later when it is necessary to write to NV, then the TPM // will go into failure mode. NvCheckState(); // Due to the limitations of the simulation, TPM clock must be explicitly // synchronized with the system clock whenever a command is received. // This function call is not necessary in a hardware TPM. However, taking // a snapshot of the hardware timer at the beginning of the command allows // the time value to be consistent for the duration of the command execution. TimeUpdateToCurrent(); // Any command through this function will unceremoniously end the // _TPM_Hash_Data/_TPM_Hash_End sequence. if(g_DRTMHandle != TPM_RH_UNASSIGNED) ObjectTerminateEvent(); // Get command buffer size and command buffer. command.parameterBuffer = request; command.parameterSize = requestSize; // Parse command header: tag, commandSize and command.code. // First parse the tag. The unmarshaling routine will validate // that it is either TPM_ST_SESSIONS or TPM_ST_NO_SESSIONS. result = TPMI_ST_COMMAND_TAG_Unmarshal(&command.tag, &command.parameterBuffer, &command.parameterSize); if(result != TPM_RC_SUCCESS) goto Cleanup; // Unmarshal the commandSize indicator. result = UINT32_Unmarshal(&commandSize, &command.parameterBuffer, &command.parameterSize); if(result != TPM_RC_SUCCESS) goto Cleanup; // On a TPM that receives bytes on a port, the number of bytes that were // received on that port is requestSize it must be identical to commandSize. // In addition, commandSize must not be larger than MAX_COMMAND_SIZE allowed // by the implementation. The check against MAX_COMMAND_SIZE may be redundant // as the input processing (the function that receives the command bytes and // places them in the input buffer) would likely have the input truncated when // it reaches MAX_COMMAND_SIZE, and requestSize would not equal commandSize. if(commandSize != requestSize || commandSize > MAX_COMMAND_SIZE) { result = TPM_RC_COMMAND_SIZE; goto Cleanup; } // Unmarshal the command code. result = TPM_CC_Unmarshal(&command.code, &command.parameterBuffer, &command.parameterSize); if(result != TPM_RC_SUCCESS) goto Cleanup; // Check to see if the command is implemented. command.index = CommandCodeToCommandIndex(command.code); if(UNIMPLEMENTED_COMMAND_INDEX == command.index) { result = TPM_RC_COMMAND_CODE; goto Cleanup; } #if FIELD_UPGRADE_IMPLEMENTED == YES // If the TPM is in FUM, then the only allowed command is // TPM_CC_FieldUpgradeData. if(IsFieldUgradeMode() && (command.code != TPM_CC_FieldUpgradeData)) { result = TPM_RC_UPGRADE; goto Cleanup; } else #endif // Excepting FUM, the TPM only accepts TPM2_Startup() after // _TPM_Init. After getting a TPM2_Startup(), TPM2_Startup() // is no longer allowed. if((!TPMIsStarted() && command.code != TPM_CC_Startup) || (TPMIsStarted() && command.code == TPM_CC_Startup)) { result = TPM_RC_INITIALIZE; goto Cleanup; } // Start regular command process. NvIndexCacheInit(); // Parse Handle buffer. result = ParseHandleBuffer(&command); if(result != TPM_RC_SUCCESS) goto Cleanup; // All handles in the handle area are required to reference TPM-resident // entities. result = EntityGetLoadStatus(&command); if(result != TPM_RC_SUCCESS) goto Cleanup; // Authorization session handling for the command. ClearCpRpHashes(&command); if(command.tag == TPM_ST_SESSIONS) { // Find out session buffer size. result = UINT32_Unmarshal((UINT32 *)&command.authSize, &command.parameterBuffer, &command.parameterSize); if(result != TPM_RC_SUCCESS) goto Cleanup; // Perform sanity check on the unmarshaled value. If it is smaller than // the smallest possible session or larger than the remaining size of // the command, then it is an error. NOTE: This check could pass but the // session size could still be wrong. That will be determined after the // sessions are unmarshaled. if(command.authSize < 9 || command.authSize > command.parameterSize) { result = TPM_RC_SIZE; goto Cleanup; } command.parameterSize -= command.authSize; // The actions of ParseSessionBuffer() are described in the introduction. // As the sessions are parsed command.parameterBuffer is advanced so, on a // successful return, command.parameterBuffer should be pointing at the // first byte of the parameters. result = ParseSessionBuffer(&command); if(result != TPM_RC_SUCCESS) goto Cleanup; } else { command.authSize = 0; // The command has no authorization sessions. // If the command requires authorizations, then CheckAuthNoSession() will // return an error. result = CheckAuthNoSession(&command); if(result != TPM_RC_SUCCESS) goto Cleanup; } // Set up the response buffer pointers. CommandDispatch will marshal the // response parameters starting at the address in command.responseBuffer. //*response = MemoryGetResponseBuffer(command.index); // leave space for the command header command.responseBuffer = *response + STD_RESPONSE_HEADER; // leave space for the parameter size field if needed if(command.tag == TPM_ST_SESSIONS) command.responseBuffer += sizeof(UINT32); if(IsHandleInResponse(command.index)) command.responseBuffer += sizeof(TPM_HANDLE); // CommandDispatcher returns a response handle buffer and a response parameter // buffer if it succeeds. It will also set the parameterSize field in the // buffer if the tag is TPM_RC_SESSIONS. result = CommandDispatcher(&command); if(result != TPM_RC_SUCCESS) goto Cleanup; // Build the session area at the end of the parameter area. BuildResponseSession(&command); Cleanup: if(g_clearOrderly == TRUE && NV_IS_ORDERLY) { #if USE_DA_USED gp.orderlyState = g_daUsed ? SU_DA_USED_VALUE : SU_NONE_VALUE; #else gp.orderlyState = SU_NONE_VALUE; #endif NV_SYNC_PERSISTENT(orderlyState); } // This implementation loads an "evict" object to a transient object slot in // RAM whenever an "evict" object handle is used in a command so that the // access to any object is the same. These temporary objects need to be // cleared from RAM whether the command succeeds or fails. ObjectCleanupEvict(); // The parameters and sessions have been marshaled. Now tack on the header and // set the sizes BuildResponseHeader(&command, *response, result); // Try to commit all the writes to NV if any NV write happened during this // command execution. This check should be made for both succeeded and failed // commands, because a failed one may trigger a NV write in DA logic as well. // This is the only place in the command execution path that may call the NV // commit. If the NV commit fails, the TPM should be put in failure mode. if((g_updateNV != UT_NONE) && !g_inFailureMode) { if(g_updateNV == UT_ORDERLY) NvUpdateIndexOrderlyData(); if(!NvCommit()) FAIL(FATAL_ERROR_INTERNAL); g_updateNV = UT_NONE; } pAssert((UINT32)command.parameterSize <= maxResponse); // Clear unused bits in response buffer. MemorySet(*response + *responseSize, 0, maxResponse - *responseSize); // as a final act, and not before, update the response size. *responseSize = (UINT32)command.parameterSize; return; }