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[dfsan] Add origin address calculation

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This is a part of https://reviews.llvm.org/D95835.

Reviewed-by: morehouse

Differential Revision: https://reviews.llvm.org/D97065
This commit is contained in:
Jianzhou Zhao 2021-02-19 17:50:02 +00:00
parent 3867db163b
commit ff60cc1168
1 changed files with 46 additions and 10 deletions
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56
lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
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@ -26,9 +26,11 @@
/// | |
/// | unused |
/// | |
/// +--------------------+ 0x200200000000 (kUnusedAddr)
/// +--------------------+ 0x300200000000 (kUnusedAddr)
/// | union table |
/// +--------------------+ 0x200000000000 (kUnionTableAddr)
/// +--------------------+ 0x300000000000 (kUnionTableAddr)
/// | origin |
/// +--------------------+ 0x200000008000 (kOriginAddr)
/// | shadow memory |
/// +--------------------+ 0x000000010000 (kShadowAddr)
/// | reserved by kernel |
@ -109,6 +111,8 @@ using namespace llvm;
// This must be consistent with ShadowWidthBits.
static const Align kShadowTLSAlignment = Align(2);
static const Align kMinOriginAlignment = Align(4);
// The size of TLS variables. These constants must be kept in sync with the ones
// in dfsan.cpp.
static const unsigned kArgTLSSize = 800;
@ -377,6 +381,7 @@ class DataFlowSanitizer {
Type *Int8Ptr;
IntegerType *OriginTy;
PointerType *OriginPtrTy;
ConstantInt *OriginBase;
/// The shadow type for all primitive types and vector types.
IntegerType *PrimitiveShadowTy;
PointerType *PrimitiveShadowPtrTy;
@ -426,7 +431,10 @@ class DataFlowSanitizer {
AttrBuilder ReadOnlyNoneAttrs;
bool DFSanRuntimeShadowMask = false;
Value *getShadowOffset(Value *Addr, IRBuilder<> &IRB);
Value *getShadowAddress(Value *Addr, Instruction *Pos);
std::pair<Value *, Value *>
getShadowOriginAddress(Value *Addr, Align InstAlignment, Instruction *Pos);
bool isInstrumented(const Function *F);
bool isInstrumented(const GlobalAlias *GA);
FunctionType *getArgsFunctionType(FunctionType *T);
@ -868,6 +876,7 @@ bool DataFlowSanitizer::init(Module &M) {
IntptrTy = DL.getIntPtrType(*Ctx);
ZeroPrimitiveShadow = ConstantInt::getSigned(PrimitiveShadowTy, 0);
ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidthBytes);
OriginBase = ConstantInt::get(IntptrTy, 0x200000000000LL);
if (IsX86_64)
ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
else if (IsMIPS64)
@ -1513,20 +1522,47 @@ void DFSanFunction::setShadow(Instruction *I, Value *Shadow) {
ValShadowMap[I] = Shadow;
}
Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
Value *DataFlowSanitizer::getShadowOffset(Value *Addr, IRBuilder<> &IRB) {
// Returns Addr & shadow_mask
assert(Addr != RetvalTLS && "Reinstrumenting?");
IRBuilder<> IRB(Pos);
Value *ShadowPtrMaskValue;
if (DFSanRuntimeShadowMask)
ShadowPtrMaskValue = IRB.CreateLoad(IntptrTy, ExternalShadowMask);
else
ShadowPtrMaskValue = ShadowPtrMask;
return IRB.CreateIntToPtr(
IRB.CreateMul(
IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy),
IRB.CreatePtrToInt(ShadowPtrMaskValue, IntptrTy)),
ShadowPtrMul),
PrimitiveShadowPtrTy);
return IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy),
IRB.CreatePtrToInt(ShadowPtrMaskValue, IntptrTy));
}
std::pair<Value *, Value *>
DataFlowSanitizer::getShadowOriginAddress(Value *Addr, Align InstAlignment,
Instruction *Pos) {
// Returns ((Addr & shadow_mask) + origin_base) & ~4UL
IRBuilder<> IRB(Pos);
Value *ShadowOffset = getShadowOffset(Addr, IRB);
Value *ShadowPtr = IRB.CreateIntToPtr(
IRB.CreateMul(ShadowOffset, ShadowPtrMul), PrimitiveShadowPtrTy);
Value *OriginPtr = nullptr;
if (shouldTrackOrigins()) {
Value *OriginLong = IRB.CreateAdd(ShadowOffset, OriginBase);
const Align Alignment = llvm::assumeAligned(InstAlignment.value());
// When alignment is >= 4, Addr must be aligned to 4, otherwise it is UB.
// So Mask is unnecessary.
if (Alignment < kMinOriginAlignment) {
uint64_t Mask = kMinOriginAlignment.value() - 1;
OriginLong = IRB.CreateAnd(OriginLong, ConstantInt::get(IntptrTy, ~Mask));
}
OriginPtr = IRB.CreateIntToPtr(OriginLong, OriginPtrTy);
}
return {ShadowPtr, OriginPtr};
}
Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
// Returns (Addr & shadow_mask) x 2
IRBuilder<> IRB(Pos);
Value *ShadowOffset = getShadowOffset(Addr, IRB);
return IRB.CreateIntToPtr(IRB.CreateMul(ShadowOffset, ShadowPtrMul),
PrimitiveShadowPtrTy);
}
Value *DFSanFunction::combineShadowsThenConvert(Type *T, Value *V1, Value *V2,