1 | /* $Id: tpm-linux.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - Trusted Platform Module (TPM) access, Linux variant.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2021-2023 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * The contents of this file may alternatively be used under the terms
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26 | * of the Common Development and Distribution License Version 1.0
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27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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28 | * in the VirtualBox distribution, in which case the provisions of the
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29 | * CDDL are applicable instead of those of the GPL.
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30 | *
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31 | * You may elect to license modified versions of this file under the
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32 | * terms and conditions of either the GPL or the CDDL or both.
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33 | *
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34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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35 | */
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36 |
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37 |
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38 | /*********************************************************************************************************************************
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39 | * Header Files *
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40 | *********************************************************************************************************************************/
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41 | #define LOG_GROUP RTLOGGROUP_DEFAULT
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42 | #include <iprt/tpm.h>
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43 |
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44 | #include <iprt/assertcompile.h>
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45 | #include <iprt/asm.h>
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46 | #include <iprt/err.h>
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47 | #include <iprt/file.h>
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48 | #include <iprt/log.h>
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49 | #include <iprt/mem.h>
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50 | #include <iprt/string.h>
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51 | #include <iprt/linux/sysfs.h>
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52 |
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53 |
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54 | /*********************************************************************************************************************************
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55 | * Defined Constants And Macros *
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56 | *********************************************************************************************************************************/
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57 |
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58 |
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59 | /*********************************************************************************************************************************
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60 | * Structures and Typedefs *
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61 | *********************************************************************************************************************************/
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62 |
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63 | /**
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64 | * Internal TPM instance data.
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65 | */
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66 | typedef struct RTTPMINT
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67 | {
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68 | /** Handle to the /dev/tpmX device. */
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69 | RTFILE hTpmDev;
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70 | /** Handle to the sysfs cancel interface. */
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71 | RTFILE hTpmCancel;
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72 | /** The deduced TPM version. */
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73 | RTTPMVERSION enmTpmVers;
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74 | /** Flag whether a request is currently being executed. */
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75 | volatile bool fReqExec;
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76 | } RTTPMINT;
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77 | /** Pointer to the internal TPM instance data. */
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78 | typedef RTTPMINT *PRTTPMINT;
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79 |
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80 |
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81 | /*********************************************************************************************************************************
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82 | * Internal Functions *
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83 | *********************************************************************************************************************************/
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84 |
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85 | RTDECL(int) RTTpmOpen(PRTTPM phTpm, uint32_t idTpm)
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86 | {
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87 | AssertPtrReturn(phTpm, VERR_INVALID_POINTER);
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88 | if (idTpm == RTTPM_ID_DEFAULT)
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89 | idTpm = 0;
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90 |
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91 | int rc = VINF_SUCCESS;
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92 | PRTTPMINT pThis = (PRTTPMINT)RTMemAllocZ(sizeof(*pThis));
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93 | if (pThis)
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94 | {
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95 | pThis->hTpmDev = NIL_RTFILE;
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96 | pThis->hTpmCancel = NIL_RTFILE;
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97 | pThis->enmTpmVers = RTTPMVERSION_UNKNOWN;
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98 | pThis->fReqExec = false;
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99 |
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100 | rc = RTFileOpenF(&pThis->hTpmDev, RTFILE_O_OPEN | RTFILE_O_READWRITE | RTFILE_O_DENY_NONE,
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101 | "/dev/tpm%u", idTpm);
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102 | if (RT_SUCCESS(rc))
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103 | {
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104 | /* Open the sysfs path to cancel a request, either /sys/class/tpm/tpmX/device/cancel or /sys/class/misc/tpmX/device/cancel. */
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105 | rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
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106 | "/sys/class/tpm/tpm%u/device/cancel", idTpm);
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107 | if (rc == VERR_FILE_NOT_FOUND)
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108 | rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
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109 | "/sys/class/misc/tpm%u/device/cancel", idTpm);
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110 | if ( RT_SUCCESS(rc)
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111 | || rc == VERR_FILE_NOT_FOUND)
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112 | {
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113 | /* Try to figure out the TPM version. */
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114 | int64_t iVersion = 0;
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115 | rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/tpm/tpm%u/tpm_version_major", idTpm);
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116 | if (rc == VERR_FILE_NOT_FOUND)
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117 | rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/misc/tpm%u/tpm_version_major", idTpm);
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118 | if (RT_SUCCESS(rc))
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119 | {
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120 | if (iVersion == 1)
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121 | pThis->enmTpmVers = RTTPMVERSION_1_2;
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122 | else if (iVersion == 2)
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123 | pThis->enmTpmVers = RTTPMVERSION_2_0;
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124 | }
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125 |
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126 | *phTpm = pThis;
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127 | return VINF_SUCCESS;
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128 | }
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129 |
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130 | RTFileClose(pThis->hTpmDev);
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131 | pThis->hTpmDev = NIL_RTFILE;
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132 | }
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133 |
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134 | RTMemFree(pThis);
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135 | }
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136 | else
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137 | rc = VERR_NO_MEMORY;
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138 | return rc;
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139 | }
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140 |
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141 |
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142 | RTDECL(int) RTTpmClose(RTTPM hTpm)
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143 | {
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144 | PRTTPMINT pThis = hTpm;
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145 |
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146 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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147 |
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148 | RTFileClose(pThis->hTpmDev);
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149 | if (pThis->hTpmCancel != NIL_RTFILE)
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150 | RTFileClose(pThis->hTpmCancel);
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151 |
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152 | pThis->hTpmDev = NIL_RTFILE;
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153 | pThis->hTpmCancel = NIL_RTFILE;
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154 | RTMemFree(pThis);
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155 | return VINF_SUCCESS;
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156 | }
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157 |
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158 |
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159 | RTDECL(RTTPMVERSION) RTTpmGetVersion(RTTPM hTpm)
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160 | {
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161 | PRTTPMINT pThis = hTpm;
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162 |
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163 | AssertPtrReturn(pThis, RTTPMVERSION_INVALID);
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164 | return pThis->enmTpmVers;
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165 | }
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166 |
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167 |
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168 | RTDECL(uint32_t) RTTpmGetLocalityMax(RTTPM hTpm)
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169 | {
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170 | RT_NOREF(hTpm);
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171 | return 0; /* On Linux only TPM locality 0 is supported. */
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172 | }
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173 |
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174 |
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175 | RTDECL(int) RTTpmReqCancel(RTTPM hTpm)
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176 | {
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177 | PRTTPMINT pThis = hTpm;
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178 |
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179 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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180 | if (pThis->hTpmCancel == NIL_RTFILE)
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181 | return VERR_NOT_SUPPORTED;
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182 |
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183 | if (ASMAtomicReadBool(&pThis->fReqExec))
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184 | {
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185 | uint8_t bCancel = '-';
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186 | return RTFileWrite(pThis->hTpmCancel, &bCancel, sizeof(bCancel), NULL /*pcbWritten*/);
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187 | }
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188 |
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189 | return VINF_SUCCESS;
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190 | }
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191 |
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192 |
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193 | RTDECL(int) RTTpmReqExec(RTTPM hTpm, uint8_t bLoc, const void *pvReq, size_t cbReq,
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194 | void *pvResp, size_t cbRespMax, size_t *pcbResp)
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195 | {
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196 | PRTTPMINT pThis = hTpm;
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197 |
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198 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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199 | AssertPtrReturn(pvReq, VERR_INVALID_POINTER);
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200 | AssertPtrReturn(pvResp, VERR_INVALID_POINTER);
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201 | AssertReturn(cbReq && cbRespMax, VERR_INVALID_PARAMETER);
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202 | AssertReturn(bLoc == 0, VERR_NOT_SUPPORTED); /** @todo There doesn't seem to be a way to use a different locality. */
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203 |
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204 | /* The request has to be supplied by a single blocking write. */
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205 | ASMAtomicXchgBool(&pThis->fReqExec, true);
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206 | int rc = RTFileWrite(pThis->hTpmDev, pvReq, cbReq, NULL /*pcbWritten*/);
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207 | if (RT_SUCCESS(rc))
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208 | {
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209 | size_t cbResp = 0;
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210 | /* The response has to be retrieved in a single read as well. */
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211 | rc = RTFileRead(pThis->hTpmDev, pvResp, cbRespMax, &cbResp);
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212 | ASMAtomicXchgBool(&pThis->fReqExec, false);
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213 | if (RT_SUCCESS(rc))
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214 | {
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215 | /* Check whether the response is complete. */
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216 | if ( cbResp >= sizeof(TPMRESPHDR)
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217 | && RTTpmRespGetSz((PCTPMRESPHDR)pvResp) == cbResp)
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218 | {
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219 | if (pcbResp)
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220 | *pcbResp = cbResp;
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221 | }
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222 | else
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223 | rc = VERR_BUFFER_OVERFLOW;
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224 | }
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225 | }
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226 |
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227 | return rc;
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228 | }
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229 |
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