Index: tools/llvm-cfi-verify/CMakeLists.txt =================================================================== --- tools/llvm-cfi-verify/CMakeLists.txt +++ tools/llvm-cfi-verify/CMakeLists.txt @@ -4,6 +4,7 @@ AllTargetsDescs AllTargetsDisassemblers AllTargetsInfos + DebugInfoDWARF MC MCParser Object Index: tools/llvm-cfi-verify/LLVMBuild.txt =================================================================== --- tools/llvm-cfi-verify/LLVMBuild.txt +++ tools/llvm-cfi-verify/LLVMBuild.txt @@ -19,4 +19,4 @@ type = Tool name = llvm-cfi-verify parent = Tools -required_libraries = all-targets MC MCDisassembler MCParser Support +required_libraries = all-targets DebugInfoDWARF MC MCDisassembler MCParser Support Index: tools/llvm-cfi-verify/lib/CMakeLists.txt =================================================================== --- tools/llvm-cfi-verify/lib/CMakeLists.txt +++ tools/llvm-cfi-verify/lib/CMakeLists.txt @@ -7,6 +7,7 @@ llvm_update_compile_flags(LLVMCFIVerify) llvm_map_components_to_libnames(libs + DebugInfoDWARF MC MCParser Object Index: tools/llvm-cfi-verify/lib/FileAnalysis.h =================================================================== --- tools/llvm-cfi-verify/lib/FileAnalysis.h +++ tools/llvm-cfi-verify/lib/FileAnalysis.h @@ -12,6 +12,7 @@ #include "llvm/ADT/DenseMap.h" #include "llvm/BinaryFormat/ELF.h" +#include "llvm/DebugInfo/DWARF/DWARFContext.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCDisassembler/MCDisassembler.h" @@ -120,6 +121,8 @@ const MCInstrInfo *getMCInstrInfo() const; const MCInstrAnalysis *getMCInstrAnalysis() const; + DWARFContext *getDWARF(); + protected: // Construct a blank object with the provided triple and features. Used in // testing, where a sub class will dependency inject protected methods to @@ -162,8 +165,12 @@ std::unique_ptr MIA; std::unique_ptr Printer; + // DWARF debug information. + std::unique_ptr DWARF; + // A mapping between the virtual memory address to the instruction metadata - // struct. + // struct. TODO(hctim): Reimplement this as a sorted vector to avoid per- + // insertion allocation. std::map Instructions; // Contains a mapping between a specific address, and a list of instructions Index: tools/llvm-cfi-verify/lib/FileAnalysis.cpp =================================================================== --- tools/llvm-cfi-verify/lib/FileAnalysis.cpp +++ tools/llvm-cfi-verify/lib/FileAnalysis.cpp @@ -11,6 +11,7 @@ #include "GraphBuilder.h" #include "llvm/BinaryFormat/ELF.h" +#include "llvm/DebugInfo/DWARF/DWARFContext.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCDisassembler/MCDisassembler.h" @@ -42,6 +43,19 @@ namespace llvm { namespace cfi_verify { +static cl::opt IgnoreDWARF( + "ignore-dwarf", + cl::desc( + "Ignore all DWARF data. This relaxes the requirements for all " + "statically linked libraries to have been compiled with '-g', but " + "will result in false positives for 'CFI unprotected' instructions."), + cl::init(false)); + +cl::opt DWARFSearchRange( + "dwarf-search-range", + cl::desc("Address search range used to determine if instruction is valid."), + cl::init(0x10)); + Expected FileAnalysis::Create(StringRef Filename) { // Open the filename provided. Expected> BinaryOrErr = @@ -242,6 +256,8 @@ return MIA.get(); } +DWARFContext *FileAnalysis::getDWARF() { return DWARF.get(); } + Error FileAnalysis::initialiseDisassemblyMembers() { std::string TripleName = ObjectTriple.getTriple(); ArchName = ""; @@ -294,6 +310,28 @@ } Error FileAnalysis::parseCodeSections() { + if (!IgnoreDWARF) { + DWARF.reset(DWARFContext::create(*Object).release()); + if (!DWARF) + return make_error("Could not create DWARF information.", + inconvertibleErrorCode()); + + bool LineInfoValid = false; + + for (auto &Unit : DWARF->compile_units()) { + const auto &LineTable = DWARF->getLineTableForUnit(Unit.get()); + if (LineTable && !LineTable->Rows.empty()) { + LineInfoValid = true; + break; + } + } + + if (!LineInfoValid) + return make_error( + "DWARF line information missing. Did you compile with '-g'?", + inconvertibleErrorCode()); + } + for (const object::SectionRef &Section : Object->sections()) { // Ensure only executable sections get analysed. if (!(object::ELFSectionRef(Section).getFlags() & ELF::SHF_EXECINSTR)) @@ -330,6 +368,13 @@ InstrMeta.VMAddress = VMAddress; InstrMeta.InstructionSize = InstructionSize; InstrMeta.Valid = ValidInstruction; + + // Check if this instruction exists in the range of the DWARF metadata. + if (DWARF && + DWARF->getLineInfoForAddressRange(InstrMeta.VMAddress, DWARFSearchRange) + .empty()) + continue; + addInstruction(InstrMeta); if (!ValidInstruction) Index: tools/llvm-cfi-verify/lib/GraphBuilder.cpp =================================================================== --- tools/llvm-cfi-verify/lib/GraphBuilder.cpp +++ tools/llvm-cfi-verify/lib/GraphBuilder.cpp @@ -221,6 +221,13 @@ continue; } + // Call instructions are not valid in the upwards traversal. + if (ParentDesc.isCall()) { + Result.IntermediateNodes[ParentMeta.VMAddress] = Address; + Result.OrphanedNodes.push_back(ParentMeta.VMAddress); + continue; + } + // Evaluate the branch target to ascertain whether this XRef is the result // of a fallthrough or the target of a branch. uint64_t BranchTarget; Index: tools/llvm-cfi-verify/lib/LLVMBuild.txt =================================================================== --- tools/llvm-cfi-verify/lib/LLVMBuild.txt +++ tools/llvm-cfi-verify/lib/LLVMBuild.txt @@ -19,4 +19,4 @@ type = Library name = CFIVerify parent = Libraries -required_libraries = MC MCDisassembler MCParser Support +required_libraries = DebugInfoDWARF MC MCDisassembler MCParser Support Index: tools/llvm-cfi-verify/llvm-cfi-verify.cpp =================================================================== --- tools/llvm-cfi-verify/llvm-cfi-verify.cpp +++ tools/llvm-cfi-verify/llvm-cfi-verify.cpp @@ -22,6 +22,7 @@ #include "llvm/BinaryFormat/ELF.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Error.h" +#include "llvm/Support/FormatVariadic.h" #include @@ -34,30 +35,64 @@ ExitOnError ExitOnErr; -void printIndirectCFInstructions(const FileAnalysis &Verifier) { - for (uint64_t Address : Verifier.getIndirectInstructions()) { - const auto &InstrMeta = Verifier.getInstructionOrDie(Address); - outs() << format_hex(Address, 2) << " |" - << Verifier.getMCInstrInfo()->getName( +void printIndirectCFInstructions(FileAnalysis &Analysis) { + uint64_t ProtectedCount = 0; + uint64_t UnprotectedCount = 0; + DWARFContext *DWARF = Analysis.getDWARF(); + + for (uint64_t Address : Analysis.getIndirectInstructions()) { + const auto &InstrMeta = Analysis.getInstructionOrDie(Address); + + if (Analysis.isIndirectInstructionCFIProtected(Address)) { + outs() << "P "; + ProtectedCount++; + } else { + outs() << "U "; + UnprotectedCount++; + } + + outs() << format_hex(Address, 2) << " | " + << Analysis.getMCInstrInfo()->getName( InstrMeta.Instruction.getOpcode()) << " "; - InstrMeta.Instruction.print(outs()); outs() << "\n"; - outs() << " Protected? " - << Verifier.isIndirectInstructionCFIProtected(Address) << "\n"; + + if (DWARF) { + for (const auto &LineKV : + DWARF->getLineInfoForAddressRange(Address, 0x10)) { + outs() << " " << format_hex(LineKV.first, 2) << " = " + << LineKV.second.FileName << ":" << LineKV.second.Line << ":" + << LineKV.second.Column << " (" << LineKV.second.FunctionName + << ")\n"; + } + } } + + if (ProtectedCount || UnprotectedCount) + outs() << formatv( + "Unprotected: {0} ({1:P}), Protected: {2} ({3:P})\n", UnprotectedCount, + (((double)UnprotectedCount) / (UnprotectedCount + ProtectedCount)), + ProtectedCount, + (((double)ProtectedCount) / (UnprotectedCount + ProtectedCount))); + else + outs() << "No indirect CF instructions found.\n"; } int main(int argc, char **argv) { - cl::ParseCommandLineOptions(argc, argv); + cl::ParseCommandLineOptions( + argc, argv, + "Identifies whether Control Flow Integrity protects all indirect control " + "flow instructions in the provided object file, DSO or binary.\nNote: " + "Anything statically linked into the provided file *must* be compiled " + "with '-g'. This can be relaxed through the '--ignore-dwarf' flag."); InitializeAllTargetInfos(); InitializeAllTargetMCs(); InitializeAllAsmParsers(); InitializeAllDisassemblers(); - FileAnalysis Verifier = ExitOnErr(FileAnalysis::Create(InputFilename)); - printIndirectCFInstructions(Verifier); + FileAnalysis Analysis = ExitOnErr(FileAnalysis::Create(InputFilename)); + printIndirectCFInstructions(Analysis); return EXIT_SUCCESS; }