1 //===--- SanitizerMetadata.cpp - Ignored entities for sanitizers ----------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Class which emits metadata consumed by sanitizer instrumentation passes. 10 // 11 //===----------------------------------------------------------------------===// 12 #include "SanitizerMetadata.h" 13 #include "CodeGenModule.h" 14 #include "clang/AST/Attr.h" 15 #include "clang/AST/Type.h" 16 #include "clang/Basic/SourceManager.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/IR/Constants.h" 19 20 using namespace clang; 21 using namespace CodeGen; 22 23 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {} 24 25 static bool isAsanHwasanOrMemTag(const SanitizerSet &SS) { 26 return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress | 27 SanitizerKind::HWAddress | SanitizerKind::MemTag); 28 } 29 30 SanitizerMask expandKernelSanitizerMasks(SanitizerMask Mask) { 31 if (Mask & (SanitizerKind::Address | SanitizerKind::KernelAddress)) 32 Mask |= SanitizerKind::Address | SanitizerKind::KernelAddress; 33 // Note: KHWASan doesn't support globals. 34 return Mask; 35 } 36 37 void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV, 38 SourceLocation Loc, StringRef Name, 39 QualType Ty, 40 SanitizerMask NoSanitizeAttrMask, 41 bool IsDynInit) { 42 SanitizerSet FsanitizeArgument = CGM.getLangOpts().Sanitize; 43 if (!isAsanHwasanOrMemTag(FsanitizeArgument)) 44 return; 45 46 FsanitizeArgument.Mask = expandKernelSanitizerMasks(FsanitizeArgument.Mask); 47 NoSanitizeAttrMask = expandKernelSanitizerMasks(NoSanitizeAttrMask); 48 SanitizerSet NoSanitizeAttrSet = {NoSanitizeAttrMask & 49 FsanitizeArgument.Mask}; 50 51 llvm::GlobalVariable::SanitizerMetadata Meta; 52 if (GV->hasSanitizerMetadata()) 53 Meta = GV->getSanitizerMetadata(); 54 55 Meta.NoAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::Address); 56 Meta.NoAddress |= CGM.isInNoSanitizeList( 57 FsanitizeArgument.Mask & SanitizerKind::Address, GV, Loc, Ty); 58 59 Meta.NoHWAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::HWAddress); 60 Meta.NoHWAddress |= CGM.isInNoSanitizeList( 61 FsanitizeArgument.Mask & SanitizerKind::HWAddress, GV, Loc, Ty); 62 63 Meta.Memtag |= 64 static_cast<bool>(FsanitizeArgument.Mask & SanitizerKind::MemtagGlobals); 65 Meta.Memtag &= !NoSanitizeAttrSet.hasOneOf(SanitizerKind::MemTag); 66 Meta.Memtag &= !CGM.isInNoSanitizeList( 67 FsanitizeArgument.Mask & SanitizerKind::MemTag, GV, Loc, Ty); 68 69 Meta.IsDynInit = IsDynInit && !Meta.NoAddress && 70 FsanitizeArgument.has(SanitizerKind::Address) && 71 !CGM.isInNoSanitizeList(SanitizerKind::Address | 72 SanitizerKind::KernelAddress, 73 GV, Loc, Ty, "init"); 74 75 GV->setSanitizerMetadata(Meta); 76 } 77 78 void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV, const VarDecl &D, 79 bool IsDynInit) { 80 if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize)) 81 return; 82 std::string QualName; 83 llvm::raw_string_ostream OS(QualName); 84 D.printQualifiedName(OS); 85 86 auto getNoSanitizeMask = [](const VarDecl &D) { 87 if (D.hasAttr<DisableSanitizerInstrumentationAttr>()) 88 return SanitizerKind::All; 89 90 SanitizerMask NoSanitizeMask; 91 for (auto *Attr : D.specific_attrs<NoSanitizeAttr>()) 92 NoSanitizeMask |= Attr->getMask(); 93 94 return NoSanitizeMask; 95 }; 96 97 reportGlobal(GV, D.getLocation(), OS.str(), D.getType(), getNoSanitizeMask(D), 98 IsDynInit); 99 } 100 101 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) { 102 reportGlobal(GV, SourceLocation(), "", QualType(), SanitizerKind::All); 103 } 104 105 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) { 106 I->setMetadata(llvm::LLVMContext::MD_nosanitize, 107 llvm::MDNode::get(CGM.getLLVMContext(), std::nullopt)); 108 } 109