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TpmFailureMode: Add missing request size checks #105

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TpmFailureMode: Add missing request size checks #105

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0fa345e
TpmFailureMode: Add missing request size checks
DemiMarie Mar 16, 2023
14837b0
TpmFailureMode: treat request shorter than 10 bytes as empty
DemiMarie Dec 9, 2023
039084a
Remove unneeded checks in failure mode unmarshaling
DemiMarie Dec 9, 2023
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51 changes: 16 additions & 35 deletions TPMCmd/tpm/src/support/TpmFail.c
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Original file line number Diff line number Diff line change
Expand Up @@ -94,26 +94,6 @@ static INT32 MarshalUint32(UINT32 integer, BYTE** buffer)
return 4;
}

//***Unmarshal32()
static BOOL Unmarshal32(UINT32* target, BYTE** buffer, INT32* size)
{
if((*size -= 4) < 0)
return FALSE;
*target = BYTE_ARRAY_TO_UINT32(*buffer);
*buffer += 4;
return TRUE;
}

//***Unmarshal16()
static BOOL Unmarshal16(UINT16* target, BYTE** buffer, INT32* size)
{
if((*size -= 2) < 0)
return FALSE;
*target = BYTE_ARRAY_TO_UINT16(*buffer);
*buffer += 2;
return TRUE;
}

//** Public Functions

//*** SetForceFailureMode()
Expand Down Expand Up @@ -182,18 +162,18 @@ void TpmFailureMode(uint32_t inRequestSize, // IN: command buffer size
UINT32 pt; // unmarshaled property type
UINT32 count; // unmarshaled property count
UINT8* buffer = inRequest;
INT32 size = inRequestSize;

// If there is no command buffer, then just return TPM_RC_FAILURE
if(inRequestSize == 0 || inRequest == NULL)
// If there is no command buffer or it is too small,
// then just return TPM_RC_FAILURE
if(inRequestSize < 10 || inRequest == NULL)
goto FailureModeReturn;
// If the header is not correct for TPM2_GetCapability() or
// TPM2_GetTestResult() then just return the in failure mode response;
if(!(Unmarshal16(&header.tag, &buffer, &size)
&& Unmarshal32(&header.size, &buffer, &size)
&& Unmarshal32(&header.code, &buffer, &size)))
goto FailureModeReturn;
if(header.tag != TPM_ST_NO_SESSIONS || header.size < 10)
header.tag = BYTE_ARRAY_TO_UINT16(buffer);
header.size = BYTE_ARRAY_TO_UINT32(buffer + 2);
header.code = BYTE_ARRAY_TO_UINT32(buffer + 6);
buffer += 10;
if(header.tag != TPM_ST_NO_SESSIONS || header.size != inRequestSize)
goto FailureModeReturn;
switch(header.code)
{
Expand All @@ -214,12 +194,13 @@ void TpmFailureMode(uint32_t inRequestSize, // IN: command buffer size
case TPM_CC_GetCapability:
// make sure that the size of the command is exactly the size
// returned for the capability, property, and count
if(header.size != (10 + (3 * sizeof(UINT32)))
// also verify that this is requesting TPM properties
|| !Unmarshal32(&capability, &buffer, &size)
|| capability != TPM_CAP_TPM_PROPERTIES
|| !Unmarshal32(&pt, &buffer, &size)
|| !Unmarshal32(&count, &buffer, &size))
if(header.size != (10 + (3 * sizeof(UINT32))))
goto FailureModeReturn;
capability = BYTE_ARRAY_TO_UINT32(buffer);
pt = BYTE_ARRAY_TO_UINT32(buffer + 4);
count = BYTE_ARRAY_TO_UINT32(buffer + 8);
// also verify that this is requesting TPM properties
if(capability != TPM_CAP_TPM_PROPERTIES)
goto FailureModeReturn;

if(count > 0)
Expand Down Expand Up @@ -326,4 +307,4 @@ void UnmarshalFail(void* type, BYTE** buffer, INT32* size)
NOT_REFERENCED(buffer);
NOT_REFERENCED(size);
FAIL(FATAL_ERROR_INTERNAL);
}
}