This module initilizes MemoryOverwriteRequestControlLock variable.\r
This module adds Variable Hook and check MemoryOverwriteRequestControlLock.\r
\r
-Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2016 - 2017, Intel Corporation. All rights reserved.<BR>\r
This program and the accompanying materials\r
are licensed and made available under the terms and conditions of the BSD License\r
which accompanies this distribution. The full text of the license may be found at\r
#include <Library/DebugLib.h>\r
#include <Library/BaseLib.h>\r
#include <Library/BaseMemoryLib.h>\r
+#include <Library/UefiBootServicesTableLib.h>\r
#include "Variable.h"\r
\r
typedef struct {\r
{MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, &gEfiMemoryOverwriteRequestControlLockGuid},\r
};\r
\r
+BOOLEAN mMorPassThru = FALSE;\r
+\r
#define MOR_LOCK_DATA_UNLOCKED 0x0\r
#define MOR_LOCK_DATA_LOCKED_WITHOUT_KEY 0x1\r
#define MOR_LOCK_DATA_LOCKED_WITH_KEY 0x2\r
MorLockStateLocked = 1,\r
} MOR_LOCK_STATE;\r
\r
+BOOLEAN mMorLockInitializationRequired = FALSE;\r
UINT8 mMorLockKey[MOR_LOCK_V2_KEY_SIZE];\r
BOOLEAN mMorLockKeyEmpty = TRUE;\r
BOOLEAN mMorLockPassThru = FALSE;\r
@retval EFI_DEVICE_ERROR The variable could not be saved due to a hardware failure.\r
@retval EFI_WRITE_PROTECTED The variable in question is read-only.\r
@retval EFI_WRITE_PROTECTED The variable in question cannot be deleted.\r
- @retval EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\r
+ @retval EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\r
set but the AuthInfo does NOT pass the validation check carried\r
out by the firmware.\r
@retval EFI_NOT_FOUND The variable trying to be updated or deleted was not found.\r
// Basic Check\r
//\r
if (Attributes == 0 || DataSize == 0 || Data == NULL) {\r
- return EFI_WRITE_PROTECTED;\r
+ //\r
+ // Permit deletion for passthru request, deny it otherwise.\r
+ //\r
+ return mMorLockPassThru ? EFI_SUCCESS : EFI_WRITE_PROTECTED;\r
}\r
\r
if ((Attributes != (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS)) ||\r
/**\r
This service is an MOR/MorLock checker handler for the SetVariable().\r
\r
- @param VariableName the name of the vendor's variable, as a\r
- Null-Terminated Unicode String\r
- @param VendorGuid Unify identifier for vendor.\r
- @param Attributes Point to memory location to return the attributes of variable. If the point\r
- is NULL, the parameter would be ignored.\r
- @param DataSize The size in bytes of Data-Buffer.\r
- @param Data Point to the content of the variable.\r
-\r
- @retval EFI_SUCCESS The MOR/MorLock check pass, and Variable driver can store the variable data.\r
- @retval EFI_INVALID_PARAMETER The MOR/MorLock data or data size or attributes is not allowed for MOR variable.\r
+ @param[in] VariableName the name of the vendor's variable, as a\r
+ Null-Terminated Unicode String\r
+ @param[in] VendorGuid Unify identifier for vendor.\r
+ @param[in] Attributes Attributes bitmask to set for the variable.\r
+ @param[in] DataSize The size in bytes of Data-Buffer.\r
+ @param[in] Data Point to the content of the variable.\r
+\r
+ @retval EFI_SUCCESS The MOR/MorLock check pass, and Variable\r
+ driver can store the variable data.\r
+ @retval EFI_INVALID_PARAMETER The MOR/MorLock data or data size or\r
+ attributes is not allowed for MOR variable.\r
@retval EFI_ACCESS_DENIED The MOR/MorLock is locked.\r
- @retval EFI_ALREADY_STARTED The MorLock variable is handled inside this function.\r
- Variable driver can just return EFI_SUCCESS.\r
+ @retval EFI_ALREADY_STARTED The MorLock variable is handled inside this\r
+ function. Variable driver can just return\r
+ EFI_SUCCESS.\r
**/\r
EFI_STATUS\r
SetVariableCheckHandlerMor (\r
// Mor Variable\r
//\r
\r
+ //\r
+ // Permit deletion for passthru request.\r
+ //\r
+ if (((Attributes == 0) || (DataSize == 0)) && mMorPassThru) {\r
+ return EFI_SUCCESS;\r
+ }\r
+\r
//\r
// Basic Check\r
//\r
}\r
\r
/**\r
- Initialization for MOR Lock Control.\r
+ Initialization for MOR Control Lock.\r
\r
- @retval EFI_SUCEESS MorLock initialization success.\r
+ @retval EFI_SUCCESS MorLock initialization success.\r
@return Others Some error occurs.\r
**/\r
EFI_STATUS\r
VOID\r
)\r
{\r
+ mMorLockInitializationRequired = TRUE;\r
+ return EFI_SUCCESS;\r
+}\r
+\r
+/**\r
+ Delayed initialization for MOR Control Lock at EndOfDxe.\r
+\r
+ This function performs any operations queued by MorLockInit().\r
+**/\r
+VOID\r
+MorLockInitAtEndOfDxe (\r
+ VOID\r
+ )\r
+{\r
+ UINTN MorSize;\r
+ EFI_STATUS MorStatus;\r
+ EFI_STATUS TcgStatus;\r
+ VOID *TcgInterface;\r
+\r
+ if (!mMorLockInitializationRequired) {\r
+ //\r
+ // The EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL has never been installed, thus\r
+ // the variable write service is unavailable. This should never happen.\r
+ //\r
+ ASSERT (FALSE);\r
+ return;\r
+ }\r
+\r
+ //\r
+ // Check if the MOR variable exists.\r
+ //\r
+ MorSize = 0;\r
+ MorStatus = VariableServiceGetVariable (\r
+ MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,\r
+ &gEfiMemoryOverwriteControlDataGuid,\r
+ NULL, // Attributes\r
+ &MorSize,\r
+ NULL // Data\r
+ );\r
+ //\r
+ // We provided a zero-sized buffer, so the above call can never succeed.\r
+ //\r
+ ASSERT (EFI_ERROR (MorStatus));\r
+\r
+ if (MorStatus == EFI_BUFFER_TOO_SMALL) {\r
+ //\r
+ // The MOR variable exists.\r
+ //\r
+ // Some OSes don't follow the TCG's Platform Reset Attack Mitigation spec\r
+ // in that the OS should never create the MOR variable, only read and write\r
+ // it -- these OSes (unintentionally) create MOR if the platform firmware\r
+ // does not produce it. Whether this is the case (from the last OS boot)\r
+ // can be deduced from the absence of the TCG / TCG2 protocols, as edk2's\r
+ // MOR implementation depends on (one of) those protocols.\r
+ //\r
+ TcgStatus = gBS->LocateProtocol (\r
+ &gEfiTcgProtocolGuid,\r
+ NULL, // Registration\r
+ &TcgInterface\r
+ );\r
+ if (EFI_ERROR (TcgStatus)) {\r
+ TcgStatus = gBS->LocateProtocol (\r
+ &gEfiTcg2ProtocolGuid,\r
+ NULL, // Registration\r
+ &TcgInterface\r
+ );\r
+ }\r
+\r
+ if (!EFI_ERROR (TcgStatus)) {\r
+ //\r
+ // The MOR variable originates from the platform firmware; set the MOR\r
+ // Control Lock variable to report the locking capability to the OS.\r
+ //\r
+ SetMorLockVariable (0);\r
+ return;\r
+ }\r
+\r
+ //\r
+ // The MOR variable's origin is inexplicable; delete it.\r
+ //\r
+ DEBUG ((\r
+ DEBUG_WARN,\r
+ "%a: deleting unexpected / unsupported variable %g:%s\n",\r
+ __FUNCTION__,\r
+ &gEfiMemoryOverwriteControlDataGuid,\r
+ MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME\r
+ ));\r
+\r
+ mMorPassThru = TRUE;\r
+ VariableServiceSetVariable (\r
+ MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,\r
+ &gEfiMemoryOverwriteControlDataGuid,\r
+ 0, // Attributes\r
+ 0, // DataSize\r
+ NULL // Data\r
+ );\r
+ mMorPassThru = FALSE;\r
+ }\r
+\r
+ //\r
+ // The MOR variable is absent; the platform firmware does not support it.\r
+ // Lock the variable so that no other module may create it.\r
+ //\r
+ VariableLockRequestToLock (\r
+ NULL, // This\r
+ MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,\r
+ &gEfiMemoryOverwriteControlDataGuid\r
+ );\r
+\r
//\r
- // Set variable to report capability to OS\r
+ // Delete the MOR Control Lock variable too (should it exists for some\r
+ // reason) and prevent other modules from creating it.\r
//\r
- return SetMorLockVariable (0);\r
+ mMorLockPassThru = TRUE;\r
+ VariableServiceSetVariable (\r
+ MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,\r
+ &gEfiMemoryOverwriteRequestControlLockGuid,\r
+ 0, // Attributes\r
+ 0, // DataSize\r
+ NULL // Data\r
+ );\r
+ mMorLockPassThru = FALSE;\r
+\r
+ VariableLockRequestToLock (\r
+ NULL, // This\r
+ MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,\r
+ &gEfiMemoryOverwriteRequestControlLockGuid\r
+ );\r
}\r
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