1 //===--- SanitizerMetadata.cpp - Blacklist for sanitizers -----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Class which emits metadata consumed by sanitizer instrumentation passes.
11 //
12 //===----------------------------------------------------------------------===//
13 #include "SanitizerMetadata.h"
14 #include "CodeGenModule.h"
15 #include "clang/AST/Type.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/IR/Constants.h"
18
19 using namespace clang;
20 using namespace CodeGen;
21
SanitizerMetadata(CodeGenModule & CGM)22 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
23
reportGlobalToASan(llvm::GlobalVariable * GV,SourceLocation Loc,StringRef Name,QualType Ty,bool IsDynInit,bool IsBlacklisted)24 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
25 SourceLocation Loc, StringRef Name,
26 QualType Ty, bool IsDynInit,
27 bool IsBlacklisted) {
28 if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
29 SanitizerKind::KernelAddress |
30 SanitizerKind::HWAddress |
31 SanitizerKind::KernelHWAddress))
32 return;
33 IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init");
34 IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty);
35
36 llvm::Metadata *LocDescr = nullptr;
37 llvm::Metadata *GlobalName = nullptr;
38 llvm::LLVMContext &VMContext = CGM.getLLVMContext();
39 if (!IsBlacklisted) {
40 // Don't generate source location and global name if it is blacklisted -
41 // it won't be instrumented anyway.
42 LocDescr = getLocationMetadata(Loc);
43 if (!Name.empty())
44 GlobalName = llvm::MDString::get(VMContext, Name);
45 }
46
47 llvm::Metadata *GlobalMetadata[] = {
48 llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName,
49 llvm::ConstantAsMetadata::get(
50 llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)),
51 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
52 llvm::Type::getInt1Ty(VMContext), IsBlacklisted))};
53
54 llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
55 llvm::NamedMDNode *AsanGlobals =
56 CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals");
57 AsanGlobals->addOperand(ThisGlobal);
58 }
59
reportGlobalToASan(llvm::GlobalVariable * GV,const VarDecl & D,bool IsDynInit)60 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
61 const VarDecl &D, bool IsDynInit) {
62 if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
63 SanitizerKind::KernelAddress |
64 SanitizerKind::HWAddress |
65 SanitizerKind::KernelHWAddress))
66 return;
67 std::string QualName;
68 llvm::raw_string_ostream OS(QualName);
69 D.printQualifiedName(OS);
70
71 bool IsBlacklisted = false;
72 for (auto Attr : D.specific_attrs<NoSanitizeAttr>())
73 if (Attr->getMask() & SanitizerKind::Address)
74 IsBlacklisted = true;
75 reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit,
76 IsBlacklisted);
77 }
78
disableSanitizerForGlobal(llvm::GlobalVariable * GV)79 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
80 // For now, just make sure the global is not modified by the ASan
81 // instrumentation.
82 if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
83 SanitizerKind::KernelAddress |
84 SanitizerKind::HWAddress |
85 SanitizerKind::KernelHWAddress))
86 reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true);
87 }
88
disableSanitizerForInstruction(llvm::Instruction * I)89 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {
90 I->setMetadata(CGM.getModule().getMDKindID("nosanitize"),
91 llvm::MDNode::get(CGM.getLLVMContext(), None));
92 }
93
getLocationMetadata(SourceLocation Loc)94 llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) {
95 PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
96 if (!PLoc.isValid())
97 return nullptr;
98 llvm::LLVMContext &VMContext = CGM.getLLVMContext();
99 llvm::Metadata *LocMetadata[] = {
100 llvm::MDString::get(VMContext, PLoc.getFilename()),
101 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
102 llvm::Type::getInt32Ty(VMContext), PLoc.getLine())),
103 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
104 llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())),
105 };
106 return llvm::MDNode::get(VMContext, LocMetadata);
107 }
108