#include "llvm/IR/CallSite.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
+#include "llvm/Support/SwapByteOrder.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
-static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000;
+static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
+static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 36;
static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
static const char *const kAsanModuleCtorName = "asan.module_ctor";
static const char *const kAsanModuleDtorName = "asan.module_dtor";
-static const int kAsanCtorAndDtorPriority = 1;
+static const uint64_t kAsanCtorAndDtorPriority = 1;
static const char *const kAsanReportErrorTemplate = "__asan_report_";
static const char *const kAsanReportLoadN = "__asan_report_load_n";
static const char *const kAsanReportStoreN = "__asan_report_store_n";
static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
static const char *const kAsanInitName = "__asan_init_v4";
-static const char *const kAsanCovModuleInitName = "__sanitizer_cov_module_init";
-static const char *const kAsanCovName = "__sanitizer_cov";
static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp";
static const char *const kAsanPtrSub = "__sanitizer_ptr_sub";
static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
static const char *const kAsanGenPrefix = "__asan_gen_";
+static const char *const kSanCovGenPrefix = "__sancov_gen_";
static const char *const kAsanPoisonStackMemoryName =
"__asan_poison_stack_memory";
static const char *const kAsanUnpoisonStackMemoryName =
// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
static const size_t kNumberOfAccessSizes = 5;
+static const unsigned kAllocaRzSize = 32;
+static const unsigned kAsanAllocaLeftMagic = 0xcacacacaU;
+static const unsigned kAsanAllocaRightMagic = 0xcbcbcbcbU;
+static const unsigned kAsanAllocaPartialVal1 = 0xcbcbcb00U;
+static const unsigned kAsanAllocaPartialVal2 = 0x000000cbU;
+
// Command-line flags.
// This flag may need to be replaced with -f[no-]asan-reads.
// This flag may need to be replaced with -f[no]asan-globals.
static cl::opt<bool> ClGlobals("asan-globals",
cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
-static cl::opt<int> ClCoverage("asan-coverage",
- cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks, "
- "3: all blocks and critical edges"),
- cl::Hidden, cl::init(false));
-static cl::opt<int> ClCoverageBlockThreshold("asan-coverage-block-threshold",
- cl::desc("Add coverage instrumentation only to the entry block if there "
- "are more than this number of blocks."),
- cl::Hidden, cl::init(1500));
static cl::opt<bool> ClInitializers("asan-initialization-order",
cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(true));
static cl::opt<bool> ClInvalidPointerPairs("asan-detect-invalid-pointer-pair",
"asan-memory-access-callback-prefix",
cl::desc("Prefix for memory access callbacks"), cl::Hidden,
cl::init("__asan_"));
-
-// This is an experimental feature that will allow to choose between
-// instrumented and non-instrumented code at link-time.
-// If this option is on, just before instrumenting a function we create its
-// clone; if the function is not changed by asan the clone is deleted.
-// If we end up with a clone, we put the instrumented function into a section
-// called "ASAN" and the uninstrumented function into a section called "NOASAN".
-//
-// This is still a prototype, we need to figure out a way to keep two copies of
-// a function so that the linker can easily choose one of them.
-static cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions",
- cl::desc("Keep uninstrumented copies of functions"),
- cl::Hidden, cl::init(false));
+static cl::opt<bool> ClInstrumentAllocas("asan-instrument-allocas",
+ cl::desc("instrument dynamic allocas"), cl::Hidden, cl::init(false));
// These flags allow to change the shadow mapping.
// The shadow mapping looks like
STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
+STATISTIC(NumInstrumentedDynamicAllocas,
+ "Number of instrumented dynamic allocas");
STATISTIC(NumOptimizedAccessesToGlobalArray,
"Number of optimized accesses to global arrays");
STATISTIC(NumOptimizedAccessesToGlobalVar,
static ShadowMapping getShadowMapping(const Module &M, int LongSize) {
llvm::Triple TargetTriple(M.getTargetTriple());
bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
- bool IsIOS = TargetTriple.getOS() == llvm::Triple::IOS;
- bool IsFreeBSD = TargetTriple.getOS() == llvm::Triple::FreeBSD;
- bool IsLinux = TargetTriple.getOS() == llvm::Triple::Linux;
+ bool IsIOS = TargetTriple.isiOS();
+ bool IsFreeBSD = TargetTriple.isOSFreeBSD();
+ bool IsLinux = TargetTriple.isOSLinux();
bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
TargetTriple.getArch() == llvm::Triple::ppc64le;
bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
TargetTriple.getArch() == llvm::Triple::mipsel;
+ bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
+ TargetTriple.getArch() == llvm::Triple::mips64el;
ShadowMapping Mapping;
Mapping.Offset = kFreeBSD_ShadowOffset64;
else if (IsLinux && IsX86_64)
Mapping.Offset = kSmallX86_64ShadowOffset;
+ else if (IsMIPS64)
+ Mapping.Offset = kMIPS64_ShadowOffset64;
else
Mapping.Offset = kDefaultShadowOffset64;
}
/// AddressSanitizer: instrument the code in module to find memory bugs.
struct AddressSanitizer : public FunctionPass {
AddressSanitizer() : FunctionPass(ID) {
- initializeBreakCriticalEdgesPass(*PassRegistry::getPassRegistry());
+ initializeAddressSanitizerPass(*PassRegistry::getPassRegistry());
}
const char *getPassName() const override {
return "AddressSanitizerFunctionPass";
}
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<DominatorTreeWrapperPass>();
+ }
void instrumentMop(Instruction *I, bool UseCalls);
void instrumentPointerComparisonOrSubtraction(Instruction *I);
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- if (ClCoverage >= 3)
- AU.addRequiredID(BreakCriticalEdgesID);
- }
+ DominatorTree &getDominatorTree() const { return *DT; }
private:
void initializeCallbacks(Module &M);
bool LooksLikeCodeInBug11395(Instruction *I);
bool GlobalIsLinkerInitialized(GlobalVariable *G);
- bool InjectCoverage(Function &F, ArrayRef<BasicBlock*> AllBlocks);
- void InjectCoverageAtBlock(Function &F, BasicBlock &BB);
LLVMContext *C;
const DataLayout *DL;
int LongSize;
Type *IntptrTy;
ShadowMapping Mapping;
+ DominatorTree *DT;
Function *AsanCtorFunction;
Function *AsanInitFunction;
Function *AsanHandleNoReturnFunc;
- Function *AsanCovFunction;
Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
// This array is indexed by AccessIsWrite and log2(AccessSize).
Function *AsanErrorCallback[2][kNumberOfAccessSizes];
Function *AsanUnpoisonGlobals;
Function *AsanRegisterGlobals;
Function *AsanUnregisterGlobals;
- Function *AsanCovModuleInit;
};
// Stack poisoning does not play well with exception handling.
};
SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec;
+ // Stores left and right redzone shadow addresses for dynamic alloca
+ // and pointer to alloca instruction itself.
+ // LeftRzAddr is a shadow address for alloca left redzone.
+ // RightRzAddr is a shadow address for alloca right redzone.
+ struct DynamicAllocaCall {
+ AllocaInst *AI;
+ Value *LeftRzAddr;
+ Value *RightRzAddr;
+ bool Poison;
+ explicit DynamicAllocaCall(AllocaInst *AI,
+ Value *LeftRzAddr = nullptr,
+ Value *RightRzAddr = nullptr)
+ : AI(AI), LeftRzAddr(LeftRzAddr), RightRzAddr(RightRzAddr), Poison(true)
+ {}
+ };
+ SmallVector<DynamicAllocaCall, 1> DynamicAllocaVec;
+
// Maps Value to an AllocaInst from which the Value is originated.
typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy;
AllocaForValueMapTy AllocaForValue;
for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
visit(*BB);
- if (AllocaVec.empty()) return false;
+ if (AllocaVec.empty() && DynamicAllocaVec.empty()) return false;
initializeCallbacks(*F.getParent());
return true;
}
- // Finds all static Alloca instructions and puts
+ // Finds all Alloca instructions and puts
// poisoned red zones around all of them.
// Then unpoison everything back before the function returns.
void poisonStack();
RetVec.push_back(&RI);
}
+ // Unpoison dynamic allocas redzones.
+ void unpoisonDynamicAlloca(DynamicAllocaCall &AllocaCall) {
+ if (!AllocaCall.Poison)
+ return;
+ for (auto Ret : RetVec) {
+ IRBuilder<> IRBRet(Ret);
+ PointerType *Int32PtrTy = PointerType::getUnqual(IRBRet.getInt32Ty());
+ Value *Zero = Constant::getNullValue(IRBRet.getInt32Ty());
+ Value *PartialRzAddr = IRBRet.CreateSub(AllocaCall.RightRzAddr,
+ ConstantInt::get(IntptrTy, 4));
+ IRBRet.CreateStore(Zero, IRBRet.CreateIntToPtr(AllocaCall.LeftRzAddr,
+ Int32PtrTy));
+ IRBRet.CreateStore(Zero, IRBRet.CreateIntToPtr(PartialRzAddr,
+ Int32PtrTy));
+ IRBRet.CreateStore(Zero, IRBRet.CreateIntToPtr(AllocaCall.RightRzAddr,
+ Int32PtrTy));
+ }
+ }
+
+ // Right shift for BigEndian and left shift for LittleEndian.
+ Value *shiftAllocaMagic(Value *Val, IRBuilder<> &IRB, Value *Shift) {
+ return ASan.DL->isLittleEndian() ? IRB.CreateShl(Val, Shift)
+ : IRB.CreateLShr(Val, Shift);
+ }
+
+ // Compute PartialRzMagic for dynamic alloca call. Since we don't know the
+ // size of requested memory until runtime, we should compute it dynamically.
+ // If PartialSize is 0, PartialRzMagic would contain kAsanAllocaRightMagic,
+ // otherwise it would contain the value that we will use to poison the
+ // partial redzone for alloca call.
+ Value *computePartialRzMagic(Value *PartialSize, IRBuilder<> &IRB);
+
+ // Deploy and poison redzones around dynamic alloca call. To do this, we
+ // should replace this call with another one with changed parameters and
+ // replace all its uses with new address, so
+ // addr = alloca type, old_size, align
+ // is replaced by
+ // new_size = (old_size + additional_size) * sizeof(type)
+ // tmp = alloca i8, new_size, max(align, 32)
+ // addr = tmp + 32 (first 32 bytes are for the left redzone).
+ // Additional_size is added to make new memory allocation contain not only
+ // requested memory, but also left, partial and right redzones.
+ // After that, we should poison redzones:
+ // (1) Left redzone with kAsanAllocaLeftMagic.
+ // (2) Partial redzone with the value, computed in runtime by
+ // computePartialRzMagic function.
+ // (3) Right redzone with kAsanAllocaRightMagic.
+ void handleDynamicAllocaCall(DynamicAllocaCall &AllocaCall);
+
/// \brief Collect Alloca instructions we want (and can) handle.
void visitAllocaInst(AllocaInst &AI) {
if (!isInterestingAlloca(AI)) return;
StackAlignment = std::max(StackAlignment, AI.getAlignment());
- AllocaVec.push_back(&AI);
+ if (isDynamicAlloca(AI))
+ DynamicAllocaVec.push_back(DynamicAllocaCall(&AI));
+ else
+ AllocaVec.push_back(&AI);
}
/// \brief Collect lifetime intrinsic calls to check for use-after-scope
// ---------------------- Helpers.
void initializeCallbacks(Module &M);
+ bool doesDominateAllExits(const Instruction *I) const {
+ for (auto Ret : RetVec) {
+ if (!ASan.getDominatorTree().dominates(I, Ret))
+ return false;
+ }
+ return true;
+ }
+
+ bool isDynamicAlloca(AllocaInst &AI) const {
+ return AI.isArrayAllocation() || !AI.isStaticAlloca();
+ }
+
// Check if we want (and can) handle this alloca.
bool isInterestingAlloca(AllocaInst &AI) const {
- return (!AI.isArrayAllocation() && AI.isStaticAlloca() &&
- AI.getAllocatedType()->isSized() &&
+ return (AI.getAllocatedType()->isSized() &&
// alloca() may be called with 0 size, ignore it.
getAllocaSizeInBytes(&AI) > 0);
}
} // namespace
char AddressSanitizer::ID = 0;
-INITIALIZE_PASS(AddressSanitizer, "asan",
+INITIALIZE_PASS_BEGIN(AddressSanitizer, "asan",
+ "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
+ false, false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_END(AddressSanitizer, "asan",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
false, false)
FunctionPass *llvm::createAddressSanitizerFunctionPass() {
}
static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
- return G->getName().find(kAsanGenPrefix) == 0;
+ return G->getName().find(kAsanGenPrefix) == 0 ||
+ G->getName().find(kSanCovGenPrefix) == 0;
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
}
// If I is an interesting memory access, return the PointerOperand
-// and set IsWrite/Alignment. Otherwise return NULL.
+// and set IsWrite/Alignment. Otherwise return nullptr.
static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
unsigned *Alignment) {
// Skip memory accesses inserted by another instrumentation.
ConstantStruct *CS = cast<ConstantStruct>(OP);
// Must have a function or null ptr.
- // (CS->getOperand(0) is the init priority.)
if (Function* F = dyn_cast<Function>(CS->getOperand(1))) {
- if (F->getName() != kAsanModuleCtorName)
- poisonOneInitializer(*F, ModuleName);
+ if (F->getName() == kAsanModuleCtorName) continue;
+ ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
+ // Don't instrument CTORs that will run before asan.module_ctor.
+ if (Priority->getLimitedValue() <= kAsanCtorAndDtorPriority) continue;
+ poisonOneInitializer(*F, ModuleName);
}
}
}
// For now, just ignore this Global if the alignment is large.
if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
- // Ignore all the globals with the names starting with "\01L_OBJC_".
- // Many of those are put into the .cstring section. The linker compresses
- // that section by removing the spare \0s after the string terminator, so
- // our redzones get broken.
- if ((G->getName().find("\01L_OBJC_") == 0) ||
- (G->getName().find("\01l_OBJC_") == 0)) {
- DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G << "\n");
- return false;
- }
-
if (G->hasSection()) {
StringRef Section(G->getSection());
// Ignore the globals from the __OBJC section. The ObjC runtime assumes
DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
return false;
}
+ if (Section.startswith("__TEXT,__objc_methname,cstring_literals")) {
+ DEBUG(dbgs() << "Ignoring objc_methname cstring global: " << *G << "\n");
+ return false;
+ }
+
// Callbacks put into the CRT initializer/terminator sections
// should not be instrumented.
IRBuilder<> IRB(*C);
// Declare our poisoning and unpoisoning functions.
AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL));
+ kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, nullptr));
AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
+ kAsanUnpoisonGlobalsName, IRB.getVoidTy(), nullptr));
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
// Declare functions that register/unregister globals.
AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanRegisterGlobalsName, IRB.getVoidTy(),
- IntptrTy, IntptrTy, NULL));
+ IntptrTy, IntptrTy, nullptr));
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanUnregisterGlobalsName,
- IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
- AsanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanCovModuleInitName,
- IRB.getVoidTy(), IntptrTy, NULL));
- AsanCovModuleInit->setLinkage(Function::ExternalLinkage);
}
// This function replaces all global variables with new variables that have
// We initialize an array of such structures and pass it to a run-time call.
StructType *GlobalStructTy =
StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
- IntptrTy, IntptrTy, NULL);
+ IntptrTy, IntptrTy, nullptr);
SmallVector<Constant *, 16> Initializers(n);
bool HasDynamicallyInitializedGlobals = false;
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
- StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
+ StructType *NewTy = StructType::get(Ty, RightRedZoneTy, nullptr);
Constant *NewInitializer = ConstantStruct::get(
NewTy, G->getInitializer(),
- Constant::getNullValue(RightRedZoneTy), NULL);
+ Constant::getNullValue(RightRedZoneTy), nullptr);
// Create a new global variable with enough space for a redzone.
GlobalValue::LinkageTypes Linkage = G->getLinkage();
ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
ConstantExpr::getPointerCast(Name, IntptrTy),
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
- ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, NULL);
+ ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, nullptr);
if (ClInitializers && MD.IsDynInit)
HasDynamicallyInitializedGlobals = true;
assert(CtorFunc);
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
- if (ClCoverage > 0) {
- Function *CovFunc = M.getFunction(kAsanCovName);
- int nCov = CovFunc ? CovFunc->getNumUses() : 0;
- IRB.CreateCall(AsanCovModuleInit, ConstantInt::get(IntptrTy, nCov));
- Changed = true;
- }
-
if (ClGlobals)
Changed |= InstrumentGlobals(IRB, M);
AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
checkInterfaceFunction(
M.getOrInsertFunction(kAsanReportErrorTemplate + Suffix,
- IRB.getVoidTy(), IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, nullptr));
AsanMemoryAccessCallback[AccessIsWrite][AccessSizeIndex] =
checkInterfaceFunction(
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + Suffix,
- IRB.getVoidTy(), IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, nullptr));
}
}
AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanMemoryAccessCallbackSized[0] = checkInterfaceFunction(
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "loadN",
- IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanMemoryAccessCallbackSized[1] = checkInterfaceFunction(
M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "storeN",
- IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanMemmove = checkInterfaceFunction(M.getOrInsertFunction(
ClMemoryAccessCallbackPrefix + "memmove", IRB.getInt8PtrTy(),
- IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL));
+ IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
AsanMemcpy = checkInterfaceFunction(M.getOrInsertFunction(
ClMemoryAccessCallbackPrefix + "memcpy", IRB.getInt8PtrTy(),
- IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL));
+ IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
AsanMemset = checkInterfaceFunction(M.getOrInsertFunction(
ClMemoryAccessCallbackPrefix + "memset", IRB.getInt8PtrTy(),
- IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, NULL));
+ IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, nullptr));
AsanHandleNoReturnFunc = checkInterfaceFunction(
- M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
- AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanCovName, IRB.getVoidTy(), NULL));
+ M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), nullptr));
+
AsanPtrCmpFunction = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanPtrSubFunction = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
// We insert an empty inline asm after __asan_report* to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
// call __asan_init in the module ctor.
IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
AsanInitFunction = checkInterfaceFunction(
- M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
+ M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), nullptr));
AsanInitFunction->setLinkage(Function::ExternalLinkage);
IRB.CreateCall(AsanInitFunction);
return false;
}
-void AddressSanitizer::InjectCoverageAtBlock(Function &F, BasicBlock &BB) {
- BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
- // Skip static allocas at the top of the entry block so they don't become
- // dynamic when we split the block. If we used our optimized stack layout,
- // then there will only be one alloca and it will come first.
- for (; IP != BE; ++IP) {
- AllocaInst *AI = dyn_cast<AllocaInst>(IP);
- if (!AI || !AI->isStaticAlloca())
- break;
- }
-
- DebugLoc EntryLoc = IP->getDebugLoc().getFnDebugLoc(*C);
- IRBuilder<> IRB(IP);
- IRB.SetCurrentDebugLocation(EntryLoc);
- Type *Int8Ty = IRB.getInt8Ty();
- GlobalVariable *Guard = new GlobalVariable(
- *F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage,
- Constant::getNullValue(Int8Ty), "__asan_gen_cov_" + F.getName());
- LoadInst *Load = IRB.CreateLoad(Guard);
- Load->setAtomic(Monotonic);
- Load->setAlignment(1);
- Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load);
- Instruction *Ins = SplitBlockAndInsertIfThen(
- Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
- IRB.SetInsertPoint(Ins);
- IRB.SetCurrentDebugLocation(EntryLoc);
- // __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
- IRB.CreateCall(AsanCovFunction);
- StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
- Store->setAtomic(Monotonic);
- Store->setAlignment(1);
-}
-
-// Poor man's coverage that works with ASan.
-// We create a Guard boolean variable with the same linkage
-// as the function and inject this code into the entry block (-asan-coverage=1)
-// or all blocks (-asan-coverage=2):
-// if (*Guard) {
-// __sanitizer_cov();
-// *Guard = 1;
-// }
-// The accesses to Guard are atomic. The rest of the logic is
-// in __sanitizer_cov (it's fine to call it more than once).
-//
-// This coverage implementation provides very limited data:
-// it only tells if a given function (block) was ever executed.
-// No counters, no per-edge data.
-// But for many use cases this is what we need and the added slowdown
-// is negligible. This simple implementation will probably be obsoleted
-// by the upcoming Clang-based coverage implementation.
-// By having it here and now we hope to
-// a) get the functionality to users earlier and
-// b) collect usage statistics to help improve Clang coverage design.
-bool AddressSanitizer::InjectCoverage(Function &F,
- ArrayRef<BasicBlock *> AllBlocks) {
- if (!ClCoverage) return false;
-
- if (ClCoverage == 1 ||
- (unsigned)ClCoverageBlockThreshold < AllBlocks.size()) {
- InjectCoverageAtBlock(F, F.getEntryBlock());
- } else {
- for (auto BB : AllBlocks)
- InjectCoverageAtBlock(F, *BB);
- }
- return true;
-}
-
bool AddressSanitizer::runOnFunction(Function &F) {
if (&F == AsanCtorFunction) return false;
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
initializeCallbacks(*F.getParent());
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+
// If needed, insert __asan_init before checking for SanitizeAddress attr.
maybeInsertAsanInitAtFunctionEntry(F);
if (Value *Addr =
isInterestingMemoryAccess(&Inst, &IsWrite, &Alignment)) {
if (ClOpt && ClOptSameTemp) {
- if (!TempsToInstrument.insert(Addr))
+ if (!TempsToInstrument.insert(Addr).second)
continue; // We've seen this temp in the current BB.
}
} else if (ClInvalidPointerPairs &&
}
}
- Function *UninstrumentedDuplicate = nullptr;
- bool LikelyToInstrument =
- !NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0);
- if (ClKeepUninstrumented && LikelyToInstrument) {
- ValueToValueMapTy VMap;
- UninstrumentedDuplicate = CloneFunction(&F, VMap, false);
- UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress);
- UninstrumentedDuplicate->setName("NOASAN_" + F.getName());
- F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate);
- }
-
bool UseCalls = false;
if (ClInstrumentationWithCallsThreshold >= 0 &&
ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold)
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
- if (InjectCoverage(F, AllBlocks))
- res = true;
-
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
- if (ClKeepUninstrumented) {
- if (!res) {
- // No instrumentation is done, no need for the duplicate.
- if (UninstrumentedDuplicate)
- UninstrumentedDuplicate->eraseFromParent();
- } else {
- // The function was instrumented. We must have the duplicate.
- assert(UninstrumentedDuplicate);
- UninstrumentedDuplicate->setSection("NOASAN");
- assert(!F.hasSection());
- F.setSection("ASAN");
- }
- }
-
return res;
}
std::string Suffix = itostr(i);
AsanStackMallocFunc[i] = checkInterfaceFunction(
M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
- IntptrTy, IntptrTy, NULL));
+ IntptrTy, IntptrTy, nullptr));
AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
- IntptrTy, IntptrTy, NULL));
+ IntptrTy, IntptrTy, nullptr));
}
- AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
- AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ AsanPoisonStackMemoryFunc = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanPoisonStackMemoryName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, nullptr));
+ AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanUnpoisonStackMemoryName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, nullptr));
}
void
}
void FunctionStackPoisoner::poisonStack() {
+ assert(AllocaVec.size() > 0 || DynamicAllocaVec.size() > 0);
+
+ if (ClInstrumentAllocas)
+ // Handle dynamic allocas.
+ for (auto &AllocaCall : DynamicAllocaVec)
+ handleDynamicAllocaCall(AllocaCall);
+
+ if (AllocaVec.size() == 0) return;
+
int StackMallocIdx = -1;
DebugLoc EntryDebugLocation = getFunctionEntryDebugLocation(F);
- assert(AllocaVec.size() > 0);
Instruction *InsBefore = AllocaVec[0];
IRBuilder<> IRB(InsBefore);
IRB.SetCurrentDebugLocation(EntryDebugLocation);
}
}
+ if (ClInstrumentAllocas)
+ // Unpoison dynamic allocas.
+ for (auto &AllocaCall : DynamicAllocaVec)
+ unpoisonDynamicAlloca(AllocaCall);
+
// We are done. Remove the old unused alloca instructions.
for (auto AI : AllocaVec)
AI->eraseFromParent();
AllocaForValue[V] = Res;
return Res;
}
+
+// Compute PartialRzMagic for dynamic alloca call. PartialRzMagic is
+// constructed from two separate 32-bit numbers: PartialRzMagic = Val1 | Val2.
+// (1) Val1 is resposible for forming base value for PartialRzMagic, containing
+// only 00 for fully addressable and 0xcb for fully poisoned bytes for each
+// 8-byte chunk of user memory respectively.
+// (2) Val2 forms the value for marking first poisoned byte in shadow memory
+// with appropriate value (0x01 - 0x07 or 0xcb if Padding % 8 == 0).
+
+// Shift = Padding & ~7; // the number of bits we need to shift to access first
+// chunk in shadow memory, containing nonzero bytes.
+// Example:
+// Padding = 21 Padding = 16
+// Shadow: |00|00|05|cb| Shadow: |00|00|cb|cb|
+// ^ ^
+// | |
+// Shift = 21 & ~7 = 16 Shift = 16 & ~7 = 16
+//
+// Val1 = 0xcbcbcbcb << Shift;
+// PartialBits = Padding ? Padding & 7 : 0xcb;
+// Val2 = PartialBits << Shift;
+// Result = Val1 | Val2;
+Value *FunctionStackPoisoner::computePartialRzMagic(Value *PartialSize,
+ IRBuilder<> &IRB) {
+ PartialSize = IRB.CreateIntCast(PartialSize, IRB.getInt32Ty(), false);
+ Value *Shift = IRB.CreateAnd(PartialSize, IRB.getInt32(~7));
+ unsigned Val1Int = kAsanAllocaPartialVal1;
+ unsigned Val2Int = kAsanAllocaPartialVal2;
+ if (!ASan.DL->isLittleEndian()) {
+ Val1Int = sys::getSwappedBytes(Val1Int);
+ Val2Int = sys::getSwappedBytes(Val2Int);
+ }
+ Value *Val1 = shiftAllocaMagic(IRB.getInt32(Val1Int), IRB, Shift);
+ Value *PartialBits = IRB.CreateAnd(PartialSize, IRB.getInt32(7));
+ // For BigEndian get 0x000000YZ -> 0xYZ000000.
+ if (ASan.DL->isBigEndian())
+ PartialBits = IRB.CreateShl(PartialBits, IRB.getInt32(24));
+ Value *Val2 = IRB.getInt32(Val2Int);
+ Value *Cond =
+ IRB.CreateICmpNE(PartialBits, Constant::getNullValue(IRB.getInt32Ty()));
+ Val2 = IRB.CreateSelect(Cond, shiftAllocaMagic(PartialBits, IRB, Shift),
+ shiftAllocaMagic(Val2, IRB, Shift));
+ return IRB.CreateOr(Val1, Val2);
+}
+
+void FunctionStackPoisoner::handleDynamicAllocaCall(
+ DynamicAllocaCall &AllocaCall) {
+ AllocaInst *AI = AllocaCall.AI;
+ if (!doesDominateAllExits(AI)) {
+ // We do not yet handle complex allocas
+ AllocaCall.Poison = false;
+ return;
+ }
+
+ IRBuilder<> IRB(AI);
+
+ PointerType *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
+ const unsigned Align = std::max(kAllocaRzSize, AI->getAlignment());
+ const uint64_t AllocaRedzoneMask = kAllocaRzSize - 1;
+
+ Value *Zero = Constant::getNullValue(IntptrTy);
+ Value *AllocaRzSize = ConstantInt::get(IntptrTy, kAllocaRzSize);
+ Value *AllocaRzMask = ConstantInt::get(IntptrTy, AllocaRedzoneMask);
+ Value *NotAllocaRzMask = ConstantInt::get(IntptrTy, ~AllocaRedzoneMask);
+
+ // Since we need to extend alloca with additional memory to locate
+ // redzones, and OldSize is number of allocated blocks with
+ // ElementSize size, get allocated memory size in bytes by
+ // OldSize * ElementSize.
+ unsigned ElementSize = ASan.DL->getTypeAllocSize(AI->getAllocatedType());
+ Value *OldSize = IRB.CreateMul(AI->getArraySize(),
+ ConstantInt::get(IntptrTy, ElementSize));
+
+ // PartialSize = OldSize % 32
+ Value *PartialSize = IRB.CreateAnd(OldSize, AllocaRzMask);
+
+ // Misalign = kAllocaRzSize - PartialSize;
+ Value *Misalign = IRB.CreateSub(AllocaRzSize, PartialSize);
+
+ // PartialPadding = Misalign != kAllocaRzSize ? Misalign : 0;
+ Value *Cond = IRB.CreateICmpNE(Misalign, AllocaRzSize);
+ Value *PartialPadding = IRB.CreateSelect(Cond, Misalign, Zero);
+
+ // AdditionalChunkSize = Align + PartialPadding + kAllocaRzSize
+ // Align is added to locate left redzone, PartialPadding for possible
+ // partial redzone and kAllocaRzSize for right redzone respectively.
+ Value *AdditionalChunkSize = IRB.CreateAdd(
+ ConstantInt::get(IntptrTy, Align + kAllocaRzSize), PartialPadding);
+
+ Value *NewSize = IRB.CreateAdd(OldSize, AdditionalChunkSize);
+
+ // Insert new alloca with new NewSize and Align params.
+ AllocaInst *NewAlloca = IRB.CreateAlloca(IRB.getInt8Ty(), NewSize);
+ NewAlloca->setAlignment(Align);
+
+ // NewAddress = Address + Align
+ Value *NewAddress = IRB.CreateAdd(IRB.CreatePtrToInt(NewAlloca, IntptrTy),
+ ConstantInt::get(IntptrTy, Align));
+
+ Value *NewAddressPtr = IRB.CreateIntToPtr(NewAddress, AI->getType());
+
+ // LeftRzAddress = NewAddress - kAllocaRzSize
+ Value *LeftRzAddress = IRB.CreateSub(NewAddress, AllocaRzSize);
+
+ // Poisoning left redzone.
+ AllocaCall.LeftRzAddr = ASan.memToShadow(LeftRzAddress, IRB);
+ IRB.CreateStore(ConstantInt::get(IRB.getInt32Ty(), kAsanAllocaLeftMagic),
+ IRB.CreateIntToPtr(AllocaCall.LeftRzAddr, Int32PtrTy));
+
+ // PartialRzAligned = PartialRzAddr & ~AllocaRzMask
+ Value *PartialRzAddr = IRB.CreateAdd(NewAddress, OldSize);
+ Value *PartialRzAligned = IRB.CreateAnd(PartialRzAddr, NotAllocaRzMask);
+
+ // Poisoning partial redzone.
+ Value *PartialRzMagic = computePartialRzMagic(PartialSize, IRB);
+ Value *PartialRzShadowAddr = ASan.memToShadow(PartialRzAligned, IRB);
+ IRB.CreateStore(PartialRzMagic,
+ IRB.CreateIntToPtr(PartialRzShadowAddr, Int32PtrTy));
+
+ // RightRzAddress
+ // = (PartialRzAddr + AllocaRzMask) & ~AllocaRzMask
+ Value *RightRzAddress = IRB.CreateAnd(
+ IRB.CreateAdd(PartialRzAddr, AllocaRzMask), NotAllocaRzMask);
+
+ // Poisoning right redzone.
+ AllocaCall.RightRzAddr = ASan.memToShadow(RightRzAddress, IRB);
+ IRB.CreateStore(ConstantInt::get(IRB.getInt32Ty(), kAsanAllocaRightMagic),
+ IRB.CreateIntToPtr(AllocaCall.RightRzAddr, Int32PtrTy));
+
+ // Replace all uses of AddessReturnedByAlloca with NewAddress.
+ AI->replaceAllUsesWith(NewAddressPtr);
+
+ // We are done. Erase old alloca and store left, partial and right redzones
+ // shadow addresses for future unpoisoning.
+ AI->eraseFromParent();
+ NumInstrumentedDynamicAllocas++;
+}
projects / oota-llvm.git / blobdiff