/** @file Provides a secure platform-specific method to detect physically present user. Copyright (c) 2013 - 2016 Intel Corporation. SPDX-License-Identifier: BSD-2-Clause-Patent **/ #include #include #include #include #include #include #include #include // // Global variable to cache pointer to I2C protocol. // EFI_PLATFORM_TYPE mPlatformType = TypeUnknown; BOOLEAN CheckResetButtonState ( VOID ) { EFI_STATUS Status; EFI_I2C_DEVICE_ADDRESS I2CSlaveAddress; UINTN Length; UINTN ReadLength; UINT8 Buffer[2]; DEBUG ((EFI_D_INFO, "CheckResetButtonState(): mPlatformType == %d\n", mPlatformType)); if (mPlatformType == GalileoGen2) { // // Read state of Reset Button - EXP2.P1_7 // This GPIO is pulled high when the button is not pressed // This GPIO reads low when button is pressed // return PlatformPcal9555GpioGetState ( GALILEO_GEN2_IOEXP2_7BIT_SLAVE_ADDR, // IO Expander 2. 15 // P1-7. ); } if (mPlatformType == Galileo) { // // Detect the I2C Slave Address of the GPIO Expander // if (PlatformLegacyGpioGetLevel (R_QNC_GPIO_RGLVL_RESUME_WELL, GALILEO_DETERMINE_IOEXP_SLA_RESUMEWELL_GPIO)) { I2CSlaveAddress.I2CDeviceAddress = GALILEO_IOEXP_J2HI_7BIT_SLAVE_ADDR; } else { I2CSlaveAddress.I2CDeviceAddress = GALILEO_IOEXP_J2LO_7BIT_SLAVE_ADDR; } DEBUG ((EFI_D_INFO, "Galileo GPIO Expender Slave Address = %02x\n", I2CSlaveAddress.I2CDeviceAddress)); // // Read state of RESET_N_SHLD (GPORT5_BIT0) // Buffer[1] = 5; Length = 1; ReadLength = 1; Status = I2cReadMultipleByte ( I2CSlaveAddress, EfiI2CSevenBitAddrMode, &Length, &ReadLength, &Buffer[1] ); ASSERT_EFI_ERROR (Status); // // Return the state of GPORT5_BIT0 // return ((Buffer[1] & BIT0) != 0); } return TRUE; } /** This function provides a platform-specific method to detect whether the platform is operating by a physically present user. Programmatic changing of platform security policy (such as disable Secure Boot, or switch between Standard/Custom Secure Boot mode) MUST NOT be possible during Boot Services or after exiting EFI Boot Services. Only a physically present user is allowed to perform these operations. NOTE THAT: This function cannot depend on any EFI Variable Service since they are not available when this function is called in AuthenticateVariable driver. @retval TRUE The platform is operated by a physically present user. @retval FALSE The platform is NOT operated by a physically present user. **/ BOOLEAN EFIAPI UserPhysicalPresent ( VOID ) { EFI_STATUS Status; // // If user has already been detected as present, then return TRUE // if (PcdGetBool (PcdUserIsPhysicallyPresent)) { return TRUE; } // // Check to see if user is present now // if (CheckResetButtonState ()) { // // User is still not present, then return FALSE // return FALSE; } // // User has gone from not present to present state, so set // PcdUserIsPhysicallyPresent to TRUE // Status = PcdSetBoolS (PcdUserIsPhysicallyPresent, TRUE); ASSERT_EFI_ERROR (Status); return TRUE; } /** Determines if a user is physically present by reading the reset button state. @param ImageHandle The image handle of this driver. @param SystemTable A pointer to the EFI System Table. @retval EFI_SUCCESS Install the Secure Boot Helper Protocol successfully. **/ EFI_STATUS EFIAPI PlatformSecureLibInitialize ( IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable ) { EFI_STATUS Status; // // Get the platform type // mPlatformType = (EFI_PLATFORM_TYPE)PcdGet16 (PcdPlatformType); // // Read the state of the reset button when the library is initialized // Status = PcdSetBoolS (PcdUserIsPhysicallyPresent, !CheckResetButtonState ()); ASSERT_EFI_ERROR (Status); return EFI_SUCCESS; }