diff --git a/common/ffsparser.cpp b/common/ffsparser.cpp index 4e80c74..8210112 100644 --- a/common/ffsparser.cpp +++ b/common/ffsparser.cpp @@ -1243,13 +1243,15 @@ BOOLEAN FfsParser::microcodeHeaderValid(const INTEL_MICROCODE_HEADER* ucodeHeade return FALSE; } - // Check data size to be multiple of 4 - if (ucodeHeader->DataSize % 4 != 0) { + // Check data size to be multiple of 4 and less than 0x1000000 + if (ucodeHeader->DataSize % 4 != 0 || + ucodeHeader->DataSize > 0xFFFFFF) { return FALSE; } - // Check TotalSize to be greater then DataSize and multiple of 1024 - if (ucodeHeader->TotalSize <= ucodeHeader->DataSize || ucodeHeader->TotalSize % 1024 != 0) { + // Check TotalSize to be greater then DataSize snd less than 0x1000000 + if (ucodeHeader->TotalSize <= ucodeHeader->DataSize || + ucodeHeader->TotalSize > 0xFFFFFF) { return FALSE; } @@ -1279,8 +1281,13 @@ BOOLEAN FfsParser::microcodeHeaderValid(const INTEL_MICROCODE_HEADER* ucodeHeade return FALSE; } - // Check loader revision to be sane - if (ucodeHeader->LoaderRevision > INTEL_MICROCODE_MAX_LOADER_REVISION) { + // Check Revision to be less than 0x100 + if (ucodeHeader->Revision > 0xFF) { + return FALSE; + } + + // Check LoaderRevision to be less than 0x100 + if (ucodeHeader->LoaderRevision > 0xFF) { return FALSE; } @@ -4288,8 +4295,9 @@ USTATUS FfsParser::parseIntelMicrocodeHeader(const UByteArray & microcode, const // Valid microcode found UINT32 dataSize = ucodeHeader->DataSize; - if (dataSize == 0) + if (dataSize == 0) { dataSize = INTEL_MICROCODE_REAL_DATA_SIZE_ON_ZERO; + } // Recalculate the whole microcode checksum UByteArray tempMicrocode = microcode; diff --git a/common/fit.h b/common/fit.h index e88582e..8827bd0 100755 --- a/common/fit.h +++ b/common/fit.h @@ -60,27 +60,26 @@ typedef struct { // This scructure is described in Section 9.11.1 of the Intel Software Developer manual Volume 3A Part 1 typedef struct INTEL_MICROCODE_HEADER_ { - UINT32 Version; - UINT32 Revision; - UINT16 DateYear; - UINT8 DateDay; - UINT8 DateMonth; + UINT32 Version; // 0x00000001 + UINT32 Revision; // Sane values are less than 0x100 + UINT16 DateYear; // BCD + UINT8 DateDay; // BCD + UINT8 DateMonth; // BCD UINT32 CpuSignature; - UINT32 Checksum; // Checksum of Update Data and Header. Used to verify the integrity of the update header and data. - // Checksum is correct when the summation of all the DWORDs (including the extended Processor Signature Table) - // that comprise the microcode update result in 00000000H. - - UINT32 LoaderRevision; + UINT32 Checksum; // Checksum of Update Data and Header. Used to verify the integrity of the update header and data. + // Checksum is correct when the summation of all the DWORDs (including the extended Processor Signature Table) + // that comprise the microcode update result in 00000000H. + UINT32 LoaderRevision; // Sane values are less than 0x100 UINT8 CpuFlags; - UINT8 CpuFlagsReserved[3]; - UINT32 DataSize; // Specifies the size of the encrypted data in bytes, and must be a multiple of DWORDs. - // If this value is 00000000H, then the microcode update encrypted data is 2000 bytes (or 500 DWORDs). - - UINT32 TotalSize;// Specifies the total size of the microcode update in bytes. - // It is the summation of the header size, the encrypted data size and the size of the optional extended signature table. - // This value is always a multiple of 1024. - - UINT8 Reserved[12]; + UINT8 CpuFlagsReserved[3]; // Zeroes + UINT32 DataSize; // Specifies the size of the encrypted data in bytes, and must be a multiple of DWORDs. + // If this value is 00000000H, then the microcode update encrypted data is 2000 bytes (or 500 DWORDs). + // Sane values are less than 0x1000000 + UINT32 TotalSize; // Specifies the total size of the microcode update in bytes. + // It is the summation of the header size, the encrypted data size and the size of the optional extended signature table. + // This value is always a multiple of 1024 according to the spec, but Intel already breached it several times. + // Sane values are less than 0x1000000 + UINT8 Reserved[12]; // Zeroes } INTEL_MICROCODE_HEADER; #define INTEL_MICROCODE_REAL_DATA_SIZE_ON_ZERO 2000 @@ -104,7 +103,6 @@ typedef struct INTEL_MICROCODE_EXTENDED_HEADER_ENTRY_ { } INTEL_MICROCODE_EXTENDED_HEADER_ENTRY; #define INTEL_MICROCODE_HEADER_VERSION_1 0x00000001 -#define INTEL_MICROCODE_MAX_LOADER_REVISION 0x00000010 #pragma pack(pop)