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[msan] Handle param-tls overflow.

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ParamTLS (shadow for function arguments) is of limited size. This change
makes all arguments that do not fit unpoisoned, and avoids writing
past the end of a TLS buffer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220351 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov 2014-10-22 00:12:40 +00:00
parent ec4e924836
commit 61ed31cad7
1 changed files with 34 additions and 14 deletions
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48
lib/Transforms/Instrumentation/MemorySanitizer.cpp
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@ -127,6 +127,10 @@ static const uint64_t kOriginOffset64 = 1ULL << 45;
static const unsigned kMinOriginAlignment = 4;
static const unsigned kShadowTLSAlignment = 8;
// These constants must be kept in sync with the ones in msan.h.
static const unsigned kParamTLSSize = 800;
static const unsigned kRetvalTLSSize = 800;
// Accesses sizes are powers of two: 1, 2, 4, 8.
static const size_t kNumberOfAccessSizes = 4;
@ -356,7 +360,7 @@ void MemorySanitizer::initializeCallbacks(Module &M) {
// Create globals.
RetvalTLS = new GlobalVariable(
M, ArrayType::get(IRB.getInt64Ty(), 8), false,
M, ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_retval_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
RetvalOriginTLS = new GlobalVariable(
@ -364,16 +368,16 @@ void MemorySanitizer::initializeCallbacks(Module &M) {
"__msan_retval_origin_tls", nullptr, GlobalVariable::InitialExecTLSModel);
ParamTLS = new GlobalVariable(
M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
M, ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_param_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
ParamOriginTLS = new GlobalVariable(
M, ArrayType::get(OriginTy, 1000), false, GlobalVariable::ExternalLinkage,
nullptr, "__msan_param_origin_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
M, ArrayType::get(OriginTy, kParamTLSSize / 4), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_param_origin_tls",
nullptr, GlobalVariable::InitialExecTLSModel);
VAArgTLS = new GlobalVariable(
M, ArrayType::get(IRB.getInt64Ty(), 1000), false,
M, ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), false,
GlobalVariable::ExternalLinkage, nullptr, "__msan_va_arg_tls", nullptr,
GlobalVariable::InitialExecTLSModel);
VAArgOverflowSizeTLS = new GlobalVariable(
@ -952,6 +956,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
? MS.DL->getTypeAllocSize(FArg.getType()->getPointerElementType())
: MS.DL->getTypeAllocSize(FArg.getType());
if (A == &FArg) {
bool Overflow = ArgOffset + Size > kParamTLSSize;
Value *Base = getShadowPtrForArgument(&FArg, EntryIRB, ArgOffset);
if (FArg.hasByValAttr()) {
// ByVal pointer itself has clean shadow. We copy the actual
@ -962,19 +967,32 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Type *EltType = A->getType()->getPointerElementType();
ArgAlign = MS.DL->getABITypeAlignment(EltType);
}
unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
Value *Cpy = EntryIRB.CreateMemCpy(
getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
CopyAlign);
DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
(void)Cpy;
if (Overflow) {
// ParamTLS overflow.
EntryIRB.CreateMemSet(
getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB),
Constant::getNullValue(EntryIRB.getInt8Ty()), Size, ArgAlign);
} else {
unsigned CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
Value *Cpy = EntryIRB.CreateMemCpy(
getShadowPtr(V, EntryIRB.getInt8Ty(), EntryIRB), Base, Size,
CopyAlign);
DEBUG(dbgs() << " ByValCpy: " << *Cpy << "\n");
(void)Cpy;
}
*ShadowPtr = getCleanShadow(V);
} else {
*ShadowPtr = EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
if (Overflow) {
// ParamTLS overflow.
*ShadowPtr = getCleanShadow(V);
} else {
*ShadowPtr =
EntryIRB.CreateAlignedLoad(Base, kShadowTLSAlignment);
}
}
DEBUG(dbgs() << " ARG: " << FArg << " ==> " <<
**ShadowPtr << "\n");
if (MS.TrackOrigins) {
if (MS.TrackOrigins && !Overflow) {
Value *OriginPtr =
getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
setOrigin(A, EntryIRB.CreateLoad(OriginPtr));
@ -2329,6 +2347,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
assert(A->getType()->isPointerTy() &&
"ByVal argument is not a pointer!");
Size = MS.DL->getTypeAllocSize(A->getType()->getPointerElementType());
if (ArgOffset + Size > kParamTLSSize) break;
unsigned ParamAlignment = CS.getParamAlignment(i + 1);
unsigned Alignment = std::min(ParamAlignment, kShadowTLSAlignment);
Store = IRB.CreateMemCpy(ArgShadowBase,
@ -2336,6 +2355,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Size, Alignment);
} else {
Size = MS.DL->getTypeAllocSize(A->getType());
if (ArgOffset + Size > kParamTLSSize) break;
Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
kShadowTLSAlignment);
Constant *Cst = dyn_cast<Constant>(ArgShadow);