From ffb18f7710af7e1aba192ac226528e28a4011bdb Mon Sep 17 00:00:00 2001 From: Krzysztof Koch Date: Thu, 1 Aug 2019 16:44:02 -0700 Subject: ShellPkg: acpiview: DBG2: Prevent buffer overruns Modify the DBG2 table parsing logic to prevent reading past the ACPI buffer lengths provided. Modify the signature of the DumpDbgDeviceInfo() function to make it consistent with the ACPI structure processing functions in other acpiview parsers. Now, the length of the Debug Device Information Structure is read before the entire structure is dumped. This refactoring change makes it easier to stop reading beyond the DBG2 table buffer if the Debug Device Information Structure Buffer does not fit in the DBG2 buffer. For processing the first two fields of the Debug Device Information Structure (to get the length) a new ACPI_PARSER array is defined. References: - Microsoft Debug Port Table 2 (DBG2), December 10, 2015 Signed-off-by: Krzysztof Koch Reviewed-by: Alexei Fedorov Reviewed-by: Zhichao Gao Reviewed-by: Sami Mujawar --- .../Parsers/Dbg2/Dbg2Parser.c | 141 ++++++++++++++------- 1 file changed, 92 insertions(+), 49 deletions(-) (limited to 'ShellPkg') diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c index c6929695a1..869e700b9b 100644 --- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c @@ -64,10 +64,17 @@ STATIC CONST ACPI_PARSER Dbg2Parser[] = { (VOID**)&NumberDbgDeviceInfo, NULL, NULL} }; +/// An ACPI_PARSER array describing the debug device information structure +/// header. +STATIC CONST ACPI_PARSER DbgDevInfoHeaderParser[] = { + {L"Revision", 1, 0, L"0x%x", NULL, NULL, NULL, NULL}, + {L"Length", 2, 1, L"%d", NULL, (VOID**)&DbgDevInfoLen, NULL, NULL} +}; + /// An ACPI_PARSER array describing the debug device information. STATIC CONST ACPI_PARSER DbgDevInfoParser[] = { {L"Revision", 1, 0, L"0x%x", NULL, NULL, NULL, NULL}, - {L"Length", 2, 1, L"%d", NULL, (VOID**)&DbgDevInfoLen, NULL, NULL}, + {L"Length", 2, 1, L"%d", NULL, NULL, NULL, NULL}, {L"Generic Address Registers Count", 1, 3, L"0x%x", NULL, (VOID**)&GasCount, NULL, NULL}, @@ -93,76 +100,91 @@ STATIC CONST ACPI_PARSER DbgDevInfoParser[] = { /** This function parses the debug device information structure. - @param [in] Ptr Pointer to the start of the buffer. - @param [out] Length Pointer in which the length of the debug - device information is returned. + @param [in] Ptr Pointer to the start of the buffer. + @param [in] Length Length of the debug device information structure. **/ STATIC VOID EFIAPI DumpDbgDeviceInfo ( - IN UINT8* Ptr, - OUT UINT32* Length + IN UINT8* Ptr, + IN UINT16 Length ) { UINT16 Index; - UINT8* DataPtr; - UINT32* AddrSize; - - // Parse the debug device info to get the Length - ParseAcpi ( - FALSE, - 0, - "Debug Device Info", - Ptr, - 3, // Length is 2 bytes starting at offset 1 - PARSER_PARAMS (DbgDevInfoParser) - ); + UINT16 Offset; ParseAcpi ( TRUE, 2, "Debug Device Info", Ptr, - *DbgDevInfoLen, + Length, PARSER_PARAMS (DbgDevInfoParser) ); - // GAS and Address Size + // GAS Index = 0; - DataPtr = Ptr + (*BaseAddrRegOffset); - AddrSize = (UINT32*)(Ptr + (*AddrSizeOffset)); - while (Index < (*GasCount)) { + Offset = *BaseAddrRegOffset; + while ((Index++ < *GasCount) && + (Offset < Length)) { PrintFieldName (4, L"BaseAddressRegister"); - DumpGasStruct (DataPtr, 4, GAS_LENGTH); + Offset += (UINT16)DumpGasStruct ( + Ptr + Offset, + 4, + Length - Offset + ); + } + + // Make sure the array of address sizes corresponding to each GAS fit in the + // Debug Device Information structure + if ((*AddrSizeOffset + (*GasCount * sizeof (UINT32))) > Length) { + IncrementErrorCount (); + Print ( + L"ERROR: Invalid GAS count. GasCount = %d. RemainingBufferLength = %d. " \ + L"Parsing of the Debug Device Information structure aborted.\n", + *GasCount, + Length - *AddrSizeOffset + ); + return; + } + + // Address Size + Index = 0; + Offset = *AddrSizeOffset; + while ((Index++ < *GasCount) && + (Offset < Length)) { PrintFieldName (4, L"Address Size"); - Print (L"0x%x\n", AddrSize[Index]); - DataPtr += GAS_LENGTH; - Index++; + Print (L"0x%x\n", *((UINT32*)(Ptr + Offset))); + Offset += sizeof (UINT32); } // NameSpace String Index = 0; - DataPtr = Ptr + (*NameSpaceStringOffset); + Offset = *NameSpaceStringOffset; PrintFieldName (4, L"NameSpace String"); - while (Index < (*NameSpaceStringLength)) { - Print (L"%c", DataPtr[Index++]); + while ((Index++ < *NameSpaceStringLength) && + (Offset < Length)) { + Print (L"%c", *(Ptr + Offset)); + Offset++; } Print (L"\n"); // OEM Data - Index = 0; - DataPtr = Ptr + (*OEMDataOffset); - PrintFieldName (4, L"OEM Data"); - while (Index < (*OEMDataLength)) { - Print (L"%x ", DataPtr[Index++]); - if ((Index & 7) == 0) { - Print (L"\n%-*s ", OUTPUT_FIELD_COLUMN_WIDTH, L""); + if (*OEMDataOffset != 0) { + Index = 0; + Offset = *OEMDataOffset; + PrintFieldName (4, L"OEM Data"); + while ((Index++ < *OEMDataLength) && + (Offset < Length)) { + Print (L"%x ", *(Ptr + Offset)); + if ((Index & 7) == 0) { + Print (L"\n%-*s ", OUTPUT_FIELD_COLUMN_WIDTH, L""); + } + Offset++; } + Print (L"\n"); } - Print (L"\n"); - - *Length = *DbgDevInfoLen; } /** @@ -187,8 +209,7 @@ ParseAcpiDbg2 ( ) { UINT32 Offset; - UINT32 DbgDeviceInfoLength; - UINT8* DevInfoPtr; + UINT32 Index; if (!Trace) { return; @@ -202,14 +223,36 @@ ParseAcpiDbg2 ( AcpiTableLength, PARSER_PARAMS (Dbg2Parser) ); - DevInfoPtr = Ptr + Offset; - while (Offset < AcpiTableLength) { - DumpDbgDeviceInfo ( - DevInfoPtr, - &DbgDeviceInfoLength + Offset = *OffsetDbgDeviceInfo; + Index = 0; + + while (Index++ < *NumberDbgDeviceInfo) { + + // Parse the Debug Device Information Structure header to obtain Length + ParseAcpi ( + FALSE, + 0, + NULL, + Ptr + Offset, + AcpiTableLength - Offset, + PARSER_PARAMS (DbgDevInfoHeaderParser) ); - Offset += DbgDeviceInfoLength; - DevInfoPtr += DbgDeviceInfoLength; + + // Make sure the Debug Device Information structure lies inside the table. + if ((Offset + *DbgDevInfoLen) > AcpiTableLength) { + IncrementErrorCount (); + Print ( + L"ERROR: Invalid Debug Device Information structure length. " \ + L"DbgDevInfoLen = %d. RemainingTableBufferLength = %d. " \ + L"DBG2 parsing aborted.\n", + *DbgDevInfoLen, + AcpiTableLength - Offset + ); + return; + } + + DumpDbgDeviceInfo (Ptr + Offset, (*DbgDevInfoLen)); + Offset += (*DbgDevInfoLen); } } -- cgit v1.2.3