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
SanitizerMetadata(CodeGenModule & CGM)23 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
24
isAsanHwasanOrMemTag(const SanitizerSet & SS)25 static bool isAsanHwasanOrMemTag(const SanitizerSet &SS) {
26 return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress |
27 SanitizerKind::HWAddress | SanitizerKind::MemTag);
28 }
29
expandKernelSanitizerMasks(SanitizerMask Mask)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
reportGlobal(llvm::GlobalVariable * GV,SourceLocation Loc,StringRef Name,QualType Ty,SanitizerMask NoSanitizeAttrMask,bool IsDynInit)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
reportGlobal(llvm::GlobalVariable * GV,const VarDecl & D,bool IsDynInit)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
disableSanitizerForGlobal(llvm::GlobalVariable * GV)101 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
102 reportGlobal(GV, SourceLocation(), "", QualType(), SanitizerKind::All);
103 }
104