forked from OSchip/llvm-project
2137 lines
87 KiB
C++
2137 lines
87 KiB
C++
//===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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// Details of the algorithm:
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// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Instrumentation.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/Analysis/MemoryBuiltins.h"
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#include "llvm/Analysis/TargetLibraryInfo.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/DIBuilder.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/IR/InstVisitor.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/DataTypes.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/Endian.h"
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#include "llvm/Support/SwapByteOrder.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/ModuleUtils.h"
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#include "llvm/Transforms/Utils/PromoteMemToReg.h"
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#include <algorithm>
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#include <string>
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#include <system_error>
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using namespace llvm;
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#define DEBUG_TYPE "asan"
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// VMA size definition for architecture that support multiple sizes.
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// AArch64 has 3 VMA sizes: 39, 42 and 48.
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#ifndef SANITIZER_AARCH64_VMA
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# define SANITIZER_AARCH64_VMA 39
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#else
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# if SANITIZER_AARCH64_VMA != 39 && SANITIZER_AARCH64_VMA != 42
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# error "invalid SANITIZER_AARCH64_VMA size"
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# endif
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#endif
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static const uint64_t kDefaultShadowScale = 3;
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static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
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static const uint64_t kIOSShadowOffset32 = 1ULL << 30;
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static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
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static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
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static const uint64_t kLinuxKasan_ShadowOffset64 = 0xdffffc0000000000;
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static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
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static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
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static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
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#if SANITIZER_AARCH64_VMA == 39
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static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
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#elif SANITIZER_AARCH64_VMA == 42
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static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 39;
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#endif
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static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
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static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
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static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
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static const size_t kMinStackMallocSize = 1 << 6; // 64B
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static const size_t kMaxStackMallocSize = 1 << 16; // 64K
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static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
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static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
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static const char *const kAsanModuleCtorName = "asan.module_ctor";
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static const char *const kAsanModuleDtorName = "asan.module_dtor";
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static const uint64_t kAsanCtorAndDtorPriority = 1;
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static const char *const kAsanReportErrorTemplate = "__asan_report_";
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static const char *const kAsanRegisterGlobalsName = "__asan_register_globals";
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static const char *const kAsanUnregisterGlobalsName =
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"__asan_unregister_globals";
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static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
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static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
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static const char *const kAsanInitName = "__asan_init";
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static const char *const kAsanVersionCheckName =
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"__asan_version_mismatch_check_v6";
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static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp";
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static const char *const kAsanPtrSub = "__sanitizer_ptr_sub";
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static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
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static const int kMaxAsanStackMallocSizeClass = 10;
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static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
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static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
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static const char *const kAsanGenPrefix = "__asan_gen_";
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static const char *const kSanCovGenPrefix = "__sancov_gen_";
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static const char *const kAsanPoisonStackMemoryName =
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"__asan_poison_stack_memory";
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static const char *const kAsanUnpoisonStackMemoryName =
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"__asan_unpoison_stack_memory";
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static const char *const kAsanOptionDetectUAR =
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"__asan_option_detect_stack_use_after_return";
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static const char *const kAsanAllocaPoison = "__asan_alloca_poison";
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static const char *const kAsanAllocasUnpoison = "__asan_allocas_unpoison";
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// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
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static const size_t kNumberOfAccessSizes = 5;
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static const unsigned kAllocaRzSize = 32;
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// Command-line flags.
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static cl::opt<bool> ClEnableKasan(
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"asan-kernel", cl::desc("Enable KernelAddressSanitizer instrumentation"),
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cl::Hidden, cl::init(false));
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// This flag may need to be replaced with -f[no-]asan-reads.
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static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
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cl::desc("instrument read instructions"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentWrites(
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"asan-instrument-writes", cl::desc("instrument write instructions"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInstrumentAtomics(
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"asan-instrument-atomics",
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cl::desc("instrument atomic instructions (rmw, cmpxchg)"), cl::Hidden,
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cl::init(true));
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static cl::opt<bool> ClAlwaysSlowPath(
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"asan-always-slow-path",
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cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden,
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cl::init(false));
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// This flag limits the number of instructions to be instrumented
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// in any given BB. Normally, this should be set to unlimited (INT_MAX),
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// but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
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// set it to 10000.
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static cl::opt<int> ClMaxInsnsToInstrumentPerBB(
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"asan-max-ins-per-bb", cl::init(10000),
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cl::desc("maximal number of instructions to instrument in any given BB"),
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cl::Hidden);
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// This flag may need to be replaced with -f[no]asan-stack.
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static cl::opt<bool> ClStack("asan-stack", cl::desc("Handle stack memory"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
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cl::desc("Check return-after-free"),
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cl::Hidden, cl::init(true));
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// This flag may need to be replaced with -f[no]asan-globals.
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static cl::opt<bool> ClGlobals("asan-globals",
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cl::desc("Handle global objects"), cl::Hidden,
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cl::init(true));
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static cl::opt<bool> ClInitializers("asan-initialization-order",
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cl::desc("Handle C++ initializer order"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClInvalidPointerPairs(
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"asan-detect-invalid-pointer-pair",
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cl::desc("Instrument <, <=, >, >=, - with pointer operands"), cl::Hidden,
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cl::init(false));
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static cl::opt<unsigned> ClRealignStack(
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"asan-realign-stack",
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cl::desc("Realign stack to the value of this flag (power of two)"),
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cl::Hidden, cl::init(32));
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static cl::opt<int> ClInstrumentationWithCallsThreshold(
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"asan-instrumentation-with-call-threshold",
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cl::desc(
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"If the function being instrumented contains more than "
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"this number of memory accesses, use callbacks instead of "
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"inline checks (-1 means never use callbacks)."),
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cl::Hidden, cl::init(7000));
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static cl::opt<std::string> ClMemoryAccessCallbackPrefix(
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"asan-memory-access-callback-prefix",
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cl::desc("Prefix for memory access callbacks"), cl::Hidden,
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cl::init("__asan_"));
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static cl::opt<bool> ClInstrumentAllocas("asan-instrument-allocas",
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cl::desc("instrument dynamic allocas"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClSkipPromotableAllocas(
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"asan-skip-promotable-allocas",
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cl::desc("Do not instrument promotable allocas"), cl::Hidden,
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cl::init(true));
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// These flags allow to change the shadow mapping.
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// The shadow mapping looks like
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// Shadow = (Mem >> scale) + (1 << offset_log)
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static cl::opt<int> ClMappingScale("asan-mapping-scale",
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cl::desc("scale of asan shadow mapping"),
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cl::Hidden, cl::init(0));
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// Optimization flags. Not user visible, used mostly for testing
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// and benchmarking the tool.
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static cl::opt<bool> ClOpt("asan-opt", cl::desc("Optimize instrumentation"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptSameTemp(
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"asan-opt-same-temp", cl::desc("Instrument the same temp just once"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptGlobals("asan-opt-globals",
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cl::desc("Don't instrument scalar globals"),
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cl::Hidden, cl::init(true));
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static cl::opt<bool> ClOptStack(
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"asan-opt-stack", cl::desc("Don't instrument scalar stack variables"),
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cl::Hidden, cl::init(false));
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static cl::opt<bool> ClCheckLifetime(
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"asan-check-lifetime",
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cl::desc("Use llvm.lifetime intrinsics to insert extra checks"), cl::Hidden,
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cl::init(false));
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static cl::opt<bool> ClDynamicAllocaStack(
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"asan-stack-dynamic-alloca",
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cl::desc("Use dynamic alloca to represent stack variables"), cl::Hidden,
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cl::init(true));
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static cl::opt<uint32_t> ClForceExperiment(
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"asan-force-experiment",
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cl::desc("Force optimization experiment (for testing)"), cl::Hidden,
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cl::init(0));
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// Debug flags.
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static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
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cl::init(0));
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static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
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cl::Hidden, cl::init(0));
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static cl::opt<std::string> ClDebugFunc("asan-debug-func", cl::Hidden,
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cl::desc("Debug func"));
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static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
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cl::Hidden, cl::init(-1));
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static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
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cl::Hidden, cl::init(-1));
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STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
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STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
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STATISTIC(NumOptimizedAccessesToGlobalVar,
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"Number of optimized accesses to global vars");
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STATISTIC(NumOptimizedAccessesToStackVar,
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"Number of optimized accesses to stack vars");
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namespace {
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/// Frontend-provided metadata for source location.
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struct LocationMetadata {
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StringRef Filename;
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int LineNo;
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int ColumnNo;
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LocationMetadata() : Filename(), LineNo(0), ColumnNo(0) {}
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bool empty() const { return Filename.empty(); }
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void parse(MDNode *MDN) {
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assert(MDN->getNumOperands() == 3);
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MDString *DIFilename = cast<MDString>(MDN->getOperand(0));
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Filename = DIFilename->getString();
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LineNo =
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mdconst::extract<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
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ColumnNo =
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mdconst::extract<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
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}
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};
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/// Frontend-provided metadata for global variables.
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class GlobalsMetadata {
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public:
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struct Entry {
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Entry() : SourceLoc(), Name(), IsDynInit(false), IsBlacklisted(false) {}
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LocationMetadata SourceLoc;
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StringRef Name;
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bool IsDynInit;
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bool IsBlacklisted;
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};
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GlobalsMetadata() : inited_(false) {}
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void init(Module &M) {
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assert(!inited_);
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inited_ = true;
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NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
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if (!Globals) return;
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for (auto MDN : Globals->operands()) {
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// Metadata node contains the global and the fields of "Entry".
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assert(MDN->getNumOperands() == 5);
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auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
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// The optimizer may optimize away a global entirely.
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if (!GV) continue;
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// We can already have an entry for GV if it was merged with another
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// global.
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Entry &E = Entries[GV];
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if (auto *Loc = cast_or_null<MDNode>(MDN->getOperand(1)))
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E.SourceLoc.parse(Loc);
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if (auto *Name = cast_or_null<MDString>(MDN->getOperand(2)))
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E.Name = Name->getString();
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ConstantInt *IsDynInit =
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mdconst::extract<ConstantInt>(MDN->getOperand(3));
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E.IsDynInit |= IsDynInit->isOne();
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ConstantInt *IsBlacklisted =
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mdconst::extract<ConstantInt>(MDN->getOperand(4));
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E.IsBlacklisted |= IsBlacklisted->isOne();
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}
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}
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/// Returns metadata entry for a given global.
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Entry get(GlobalVariable *G) const {
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auto Pos = Entries.find(G);
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return (Pos != Entries.end()) ? Pos->second : Entry();
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}
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private:
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bool inited_;
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DenseMap<GlobalVariable *, Entry> Entries;
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};
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/// This struct defines the shadow mapping using the rule:
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/// shadow = (mem >> Scale) ADD-or-OR Offset.
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struct ShadowMapping {
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int Scale;
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uint64_t Offset;
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bool OrShadowOffset;
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};
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static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
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bool IsKasan) {
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bool IsAndroid = TargetTriple.isAndroid();
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bool IsIOS = TargetTriple.isiOS();
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bool IsFreeBSD = TargetTriple.isOSFreeBSD();
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bool IsLinux = TargetTriple.isOSLinux();
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bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
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TargetTriple.getArch() == llvm::Triple::ppc64le;
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bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
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bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
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TargetTriple.getArch() == llvm::Triple::mipsel;
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bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
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TargetTriple.getArch() == llvm::Triple::mips64el;
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bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64;
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bool IsWindows = TargetTriple.isOSWindows();
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ShadowMapping Mapping;
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if (LongSize == 32) {
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// Android is always PIE, which means that the beginning of the address
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// space is always available.
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if (IsAndroid)
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Mapping.Offset = 0;
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else if (IsMIPS32)
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Mapping.Offset = kMIPS32_ShadowOffset32;
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else if (IsFreeBSD)
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Mapping.Offset = kFreeBSD_ShadowOffset32;
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else if (IsIOS)
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Mapping.Offset = kIOSShadowOffset32;
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else if (IsWindows)
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Mapping.Offset = kWindowsShadowOffset32;
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else
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Mapping.Offset = kDefaultShadowOffset32;
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} else { // LongSize == 64
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if (IsPPC64)
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Mapping.Offset = kPPC64_ShadowOffset64;
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else if (IsFreeBSD)
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Mapping.Offset = kFreeBSD_ShadowOffset64;
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else if (IsLinux && IsX86_64) {
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if (IsKasan)
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Mapping.Offset = kLinuxKasan_ShadowOffset64;
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else
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Mapping.Offset = kSmallX86_64ShadowOffset;
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} else if (IsMIPS64)
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Mapping.Offset = kMIPS64_ShadowOffset64;
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else if (IsAArch64)
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Mapping.Offset = kAArch64_ShadowOffset64;
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else
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Mapping.Offset = kDefaultShadowOffset64;
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}
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Mapping.Scale = kDefaultShadowScale;
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if (ClMappingScale) {
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Mapping.Scale = ClMappingScale;
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}
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// OR-ing shadow offset if more efficient (at least on x86) if the offset
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// is a power of two, but on ppc64 we have to use add since the shadow
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// offset is not necessary 1/8-th of the address space.
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Mapping.OrShadowOffset = !IsPPC64 && !(Mapping.Offset & (Mapping.Offset - 1));
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return Mapping;
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}
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static size_t RedzoneSizeForScale(int MappingScale) {
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// Redzone used for stack and globals is at least 32 bytes.
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// For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
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return std::max(32U, 1U << MappingScale);
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}
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/// AddressSanitizer: instrument the code in module to find memory bugs.
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struct AddressSanitizer : public FunctionPass {
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explicit AddressSanitizer(bool CompileKernel = false)
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: FunctionPass(ID), CompileKernel(CompileKernel || ClEnableKasan) {
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initializeAddressSanitizerPass(*PassRegistry::getPassRegistry());
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}
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const char *getPassName() const override {
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return "AddressSanitizerFunctionPass";
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequired<DominatorTreeWrapperPass>();
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AU.addRequired<TargetLibraryInfoWrapperPass>();
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}
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uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
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Type *Ty = AI->getAllocatedType();
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uint64_t SizeInBytes =
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AI->getModule()->getDataLayout().getTypeAllocSize(Ty);
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return SizeInBytes;
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}
|
|
/// Check if we want (and can) handle this alloca.
|
|
bool isInterestingAlloca(AllocaInst &AI);
|
|
|
|
// Check if we have dynamic alloca.
|
|
bool isDynamicAlloca(AllocaInst &AI) const {
|
|
return AI.isArrayAllocation() || !AI.isStaticAlloca();
|
|
}
|
|
|
|
/// If it is an interesting memory access, return the PointerOperand
|
|
/// and set IsWrite/Alignment. Otherwise return nullptr.
|
|
Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
|
|
uint64_t *TypeSize, unsigned *Alignment);
|
|
void instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis, Instruction *I,
|
|
bool UseCalls, const DataLayout &DL);
|
|
void instrumentPointerComparisonOrSubtraction(Instruction *I);
|
|
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
|
|
Value *Addr, uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls, uint32_t Exp);
|
|
void instrumentUnusualSizeOrAlignment(Instruction *I, Value *Addr,
|
|
uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls,
|
|
uint32_t Exp);
|
|
Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
|
|
Value *ShadowValue, uint32_t TypeSize);
|
|
Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
|
|
bool IsWrite, size_t AccessSizeIndex,
|
|
Value *SizeArgument, uint32_t Exp);
|
|
void instrumentMemIntrinsic(MemIntrinsic *MI);
|
|
Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
|
|
bool runOnFunction(Function &F) override;
|
|
bool maybeInsertAsanInitAtFunctionEntry(Function &F);
|
|
void markEscapedLocalAllocas(Function &F);
|
|
bool doInitialization(Module &M) override;
|
|
static char ID; // Pass identification, replacement for typeid
|
|
|
|
DominatorTree &getDominatorTree() const { return *DT; }
|
|
|
|
private:
|
|
void initializeCallbacks(Module &M);
|
|
|
|
bool LooksLikeCodeInBug11395(Instruction *I);
|
|
bool GlobalIsLinkerInitialized(GlobalVariable *G);
|
|
bool isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis, Value *Addr,
|
|
uint64_t TypeSize) const;
|
|
|
|
/// Helper to cleanup per-function state.
|
|
struct FunctionStateRAII {
|
|
AddressSanitizer *Pass;
|
|
FunctionStateRAII(AddressSanitizer *Pass) : Pass(Pass) {
|
|
assert(Pass->ProcessedAllocas.empty() &&
|
|
"last pass forgot to clear cache");
|
|
}
|
|
~FunctionStateRAII() { Pass->ProcessedAllocas.clear(); }
|
|
};
|
|
|
|
LLVMContext *C;
|
|
Triple TargetTriple;
|
|
int LongSize;
|
|
bool CompileKernel;
|
|
Type *IntptrTy;
|
|
ShadowMapping Mapping;
|
|
DominatorTree *DT;
|
|
Function *AsanCtorFunction = nullptr;
|
|
Function *AsanInitFunction = nullptr;
|
|
Function *AsanHandleNoReturnFunc;
|
|
Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
|
|
// This array is indexed by AccessIsWrite, Experiment and log2(AccessSize).
|
|
Function *AsanErrorCallback[2][2][kNumberOfAccessSizes];
|
|
Function *AsanMemoryAccessCallback[2][2][kNumberOfAccessSizes];
|
|
// This array is indexed by AccessIsWrite and Experiment.
|
|
Function *AsanErrorCallbackSized[2][2];
|
|
Function *AsanMemoryAccessCallbackSized[2][2];
|
|
Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
|
|
InlineAsm *EmptyAsm;
|
|
GlobalsMetadata GlobalsMD;
|
|
DenseMap<AllocaInst *, bool> ProcessedAllocas;
|
|
|
|
friend struct FunctionStackPoisoner;
|
|
};
|
|
|
|
class AddressSanitizerModule : public ModulePass {
|
|
public:
|
|
explicit AddressSanitizerModule(bool CompileKernel = false)
|
|
: ModulePass(ID), CompileKernel(CompileKernel || ClEnableKasan) {}
|
|
bool runOnModule(Module &M) override;
|
|
static char ID; // Pass identification, replacement for typeid
|
|
const char *getPassName() const override { return "AddressSanitizerModule"; }
|
|
|
|
private:
|
|
void initializeCallbacks(Module &M);
|
|
|
|
bool InstrumentGlobals(IRBuilder<> &IRB, Module &M);
|
|
bool ShouldInstrumentGlobal(GlobalVariable *G);
|
|
void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName);
|
|
void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
|
|
size_t MinRedzoneSizeForGlobal() const {
|
|
return RedzoneSizeForScale(Mapping.Scale);
|
|
}
|
|
|
|
GlobalsMetadata GlobalsMD;
|
|
bool CompileKernel;
|
|
Type *IntptrTy;
|
|
LLVMContext *C;
|
|
Triple TargetTriple;
|
|
ShadowMapping Mapping;
|
|
Function *AsanPoisonGlobals;
|
|
Function *AsanUnpoisonGlobals;
|
|
Function *AsanRegisterGlobals;
|
|
Function *AsanUnregisterGlobals;
|
|
};
|
|
|
|
// Stack poisoning does not play well with exception handling.
|
|
// When an exception is thrown, we essentially bypass the code
|
|
// that unpoisones the stack. This is why the run-time library has
|
|
// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
|
|
// stack in the interceptor. This however does not work inside the
|
|
// actual function which catches the exception. Most likely because the
|
|
// compiler hoists the load of the shadow value somewhere too high.
|
|
// This causes asan to report a non-existing bug on 453.povray.
|
|
// It sounds like an LLVM bug.
|
|
struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
|
|
Function &F;
|
|
AddressSanitizer &ASan;
|
|
DIBuilder DIB;
|
|
LLVMContext *C;
|
|
Type *IntptrTy;
|
|
Type *IntptrPtrTy;
|
|
ShadowMapping Mapping;
|
|
|
|
SmallVector<AllocaInst *, 16> AllocaVec;
|
|
SmallSetVector<AllocaInst *, 16> NonInstrumentedStaticAllocaVec;
|
|
SmallVector<Instruction *, 8> RetVec;
|
|
unsigned StackAlignment;
|
|
|
|
Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
|
|
*AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
|
|
Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
|
|
Function *AsanAllocaPoisonFunc, *AsanAllocasUnpoisonFunc;
|
|
|
|
// Stores a place and arguments of poisoning/unpoisoning call for alloca.
|
|
struct AllocaPoisonCall {
|
|
IntrinsicInst *InsBefore;
|
|
AllocaInst *AI;
|
|
uint64_t Size;
|
|
bool DoPoison;
|
|
};
|
|
SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec;
|
|
|
|
SmallVector<AllocaInst *, 1> DynamicAllocaVec;
|
|
SmallVector<IntrinsicInst *, 1> StackRestoreVec;
|
|
AllocaInst *DynamicAllocaLayout = nullptr;
|
|
IntrinsicInst *LocalEscapeCall = nullptr;
|
|
|
|
// Maps Value to an AllocaInst from which the Value is originated.
|
|
typedef DenseMap<Value *, AllocaInst *> AllocaForValueMapTy;
|
|
AllocaForValueMapTy AllocaForValue;
|
|
|
|
bool HasNonEmptyInlineAsm = false;
|
|
bool HasReturnsTwiceCall = false;
|
|
std::unique_ptr<CallInst> EmptyInlineAsm;
|
|
|
|
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
|
|
: F(F),
|
|
ASan(ASan),
|
|
DIB(*F.getParent(), /*AllowUnresolved*/ false),
|
|
C(ASan.C),
|
|
IntptrTy(ASan.IntptrTy),
|
|
IntptrPtrTy(PointerType::get(IntptrTy, 0)),
|
|
Mapping(ASan.Mapping),
|
|
StackAlignment(1 << Mapping.Scale),
|
|
EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
|
|
|
|
bool runOnFunction() {
|
|
if (!ClStack) return false;
|
|
// Collect alloca, ret, lifetime instructions etc.
|
|
for (BasicBlock *BB : depth_first(&F.getEntryBlock())) visit(*BB);
|
|
|
|
if (AllocaVec.empty() && DynamicAllocaVec.empty()) return false;
|
|
|
|
initializeCallbacks(*F.getParent());
|
|
|
|
poisonStack();
|
|
|
|
if (ClDebugStack) {
|
|
DEBUG(dbgs() << F);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// Finds all Alloca instructions and puts
|
|
// poisoned red zones around all of them.
|
|
// Then unpoison everything back before the function returns.
|
|
void poisonStack();
|
|
|
|
void createDynamicAllocasInitStorage();
|
|
|
|
// ----------------------- Visitors.
|
|
/// \brief Collect all Ret instructions.
|
|
void visitReturnInst(ReturnInst &RI) { RetVec.push_back(&RI); }
|
|
|
|
void unpoisonDynamicAllocasBeforeInst(Instruction *InstBefore,
|
|
Value *SavedStack) {
|
|
IRBuilder<> IRB(InstBefore);
|
|
IRB.CreateCall(AsanAllocasUnpoisonFunc,
|
|
{IRB.CreateLoad(DynamicAllocaLayout),
|
|
IRB.CreatePtrToInt(SavedStack, IntptrTy)});
|
|
}
|
|
|
|
// Unpoison dynamic allocas redzones.
|
|
void unpoisonDynamicAllocas() {
|
|
for (auto &Ret : RetVec)
|
|
unpoisonDynamicAllocasBeforeInst(Ret, DynamicAllocaLayout);
|
|
|
|
for (auto &StackRestoreInst : StackRestoreVec)
|
|
unpoisonDynamicAllocasBeforeInst(StackRestoreInst,
|
|
StackRestoreInst->getOperand(0));
|
|
}
|
|
|
|
// 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.
|
|
void handleDynamicAllocaCall(AllocaInst *AI);
|
|
|
|
/// \brief Collect Alloca instructions we want (and can) handle.
|
|
void visitAllocaInst(AllocaInst &AI) {
|
|
if (!ASan.isInterestingAlloca(AI)) {
|
|
if (AI.isStaticAlloca()) NonInstrumentedStaticAllocaVec.insert(&AI);
|
|
return;
|
|
}
|
|
|
|
StackAlignment = std::max(StackAlignment, AI.getAlignment());
|
|
if (ASan.isDynamicAlloca(AI))
|
|
DynamicAllocaVec.push_back(&AI);
|
|
else
|
|
AllocaVec.push_back(&AI);
|
|
}
|
|
|
|
/// \brief Collect lifetime intrinsic calls to check for use-after-scope
|
|
/// errors.
|
|
void visitIntrinsicInst(IntrinsicInst &II) {
|
|
Intrinsic::ID ID = II.getIntrinsicID();
|
|
if (ID == Intrinsic::stackrestore) StackRestoreVec.push_back(&II);
|
|
if (ID == Intrinsic::localescape) LocalEscapeCall = &II;
|
|
if (!ClCheckLifetime) return;
|
|
if (ID != Intrinsic::lifetime_start && ID != Intrinsic::lifetime_end)
|
|
return;
|
|
// Found lifetime intrinsic, add ASan instrumentation if necessary.
|
|
ConstantInt *Size = dyn_cast<ConstantInt>(II.getArgOperand(0));
|
|
// If size argument is undefined, don't do anything.
|
|
if (Size->isMinusOne()) return;
|
|
// Check that size doesn't saturate uint64_t and can
|
|
// be stored in IntptrTy.
|
|
const uint64_t SizeValue = Size->getValue().getLimitedValue();
|
|
if (SizeValue == ~0ULL ||
|
|
!ConstantInt::isValueValidForType(IntptrTy, SizeValue))
|
|
return;
|
|
// Find alloca instruction that corresponds to llvm.lifetime argument.
|
|
AllocaInst *AI = findAllocaForValue(II.getArgOperand(1));
|
|
if (!AI) return;
|
|
bool DoPoison = (ID == Intrinsic::lifetime_end);
|
|
AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison};
|
|
AllocaPoisonCallVec.push_back(APC);
|
|
}
|
|
|
|
void visitCallSite(CallSite CS) {
|
|
Instruction *I = CS.getInstruction();
|
|
if (CallInst *CI = dyn_cast<CallInst>(I)) {
|
|
HasNonEmptyInlineAsm |=
|
|
CI->isInlineAsm() && !CI->isIdenticalTo(EmptyInlineAsm.get());
|
|
HasReturnsTwiceCall |= CI->canReturnTwice();
|
|
}
|
|
}
|
|
|
|
// ---------------------- 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;
|
|
}
|
|
|
|
/// Finds alloca where the value comes from.
|
|
AllocaInst *findAllocaForValue(Value *V);
|
|
void poisonRedZones(ArrayRef<uint8_t> ShadowBytes, IRBuilder<> &IRB,
|
|
Value *ShadowBase, bool DoPoison);
|
|
void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison);
|
|
|
|
void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase,
|
|
int Size);
|
|
Value *createAllocaForLayout(IRBuilder<> &IRB, const ASanStackFrameLayout &L,
|
|
bool Dynamic);
|
|
PHINode *createPHI(IRBuilder<> &IRB, Value *Cond, Value *ValueIfTrue,
|
|
Instruction *ThenTerm, Value *ValueIfFalse);
|
|
};
|
|
|
|
} // anonymous namespace
|
|
|
|
char AddressSanitizer::ID = 0;
|
|
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(bool CompileKernel) {
|
|
return new AddressSanitizer(CompileKernel);
|
|
}
|
|
|
|
char AddressSanitizerModule::ID = 0;
|
|
INITIALIZE_PASS(
|
|
AddressSanitizerModule, "asan-module",
|
|
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
|
|
"ModulePass",
|
|
false, false)
|
|
ModulePass *llvm::createAddressSanitizerModulePass(bool CompileKernel) {
|
|
return new AddressSanitizerModule(CompileKernel);
|
|
}
|
|
|
|
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
|
|
size_t Res = countTrailingZeros(TypeSize / 8);
|
|
assert(Res < kNumberOfAccessSizes);
|
|
return Res;
|
|
}
|
|
|
|
// \brief Create a constant for Str so that we can pass it to the run-time lib.
|
|
static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
|
|
bool AllowMerging) {
|
|
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
|
|
// We use private linkage for module-local strings. If they can be merged
|
|
// with another one, we set the unnamed_addr attribute.
|
|
GlobalVariable *GV =
|
|
new GlobalVariable(M, StrConst->getType(), true,
|
|
GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
|
|
if (AllowMerging) GV->setUnnamedAddr(true);
|
|
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
|
|
return GV;
|
|
}
|
|
|
|
/// \brief Create a global describing a source location.
|
|
static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M,
|
|
LocationMetadata MD) {
|
|
Constant *LocData[] = {
|
|
createPrivateGlobalForString(M, MD.Filename, true),
|
|
ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.LineNo),
|
|
ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.ColumnNo),
|
|
};
|
|
auto LocStruct = ConstantStruct::getAnon(LocData);
|
|
auto GV = new GlobalVariable(M, LocStruct->getType(), true,
|
|
GlobalValue::PrivateLinkage, LocStruct,
|
|
kAsanGenPrefix);
|
|
GV->setUnnamedAddr(true);
|
|
return GV;
|
|
}
|
|
|
|
static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
|
|
return G->getName().find(kAsanGenPrefix) == 0 ||
|
|
G->getName().find(kSanCovGenPrefix) == 0;
|
|
}
|
|
|
|
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
|
|
// Shadow >> scale
|
|
Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
|
|
if (Mapping.Offset == 0) return Shadow;
|
|
// (Shadow >> scale) | offset
|
|
if (Mapping.OrShadowOffset)
|
|
return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
|
|
else
|
|
return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
|
|
}
|
|
|
|
// Instrument memset/memmove/memcpy
|
|
void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
|
|
IRBuilder<> IRB(MI);
|
|
if (isa<MemTransferInst>(MI)) {
|
|
IRB.CreateCall(
|
|
isa<MemMoveInst>(MI) ? AsanMemmove : AsanMemcpy,
|
|
{IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
|
|
IRB.CreatePointerCast(MI->getOperand(1), IRB.getInt8PtrTy()),
|
|
IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
|
|
} else if (isa<MemSetInst>(MI)) {
|
|
IRB.CreateCall(
|
|
AsanMemset,
|
|
{IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
|
|
IRB.CreateIntCast(MI->getOperand(1), IRB.getInt32Ty(), false),
|
|
IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
|
|
}
|
|
MI->eraseFromParent();
|
|
}
|
|
|
|
/// Check if we want (and can) handle this alloca.
|
|
bool AddressSanitizer::isInterestingAlloca(AllocaInst &AI) {
|
|
auto PreviouslySeenAllocaInfo = ProcessedAllocas.find(&AI);
|
|
|
|
if (PreviouslySeenAllocaInfo != ProcessedAllocas.end())
|
|
return PreviouslySeenAllocaInfo->getSecond();
|
|
|
|
bool IsInteresting =
|
|
(AI.getAllocatedType()->isSized() &&
|
|
// alloca() may be called with 0 size, ignore it.
|
|
getAllocaSizeInBytes(&AI) > 0 &&
|
|
// We are only interested in allocas not promotable to registers.
|
|
// Promotable allocas are common under -O0.
|
|
(!ClSkipPromotableAllocas || !isAllocaPromotable(&AI) ||
|
|
isDynamicAlloca(AI)));
|
|
|
|
ProcessedAllocas[&AI] = IsInteresting;
|
|
return IsInteresting;
|
|
}
|
|
|
|
/// If I is an interesting memory access, return the PointerOperand
|
|
/// and set IsWrite/Alignment. Otherwise return nullptr.
|
|
Value *AddressSanitizer::isInterestingMemoryAccess(Instruction *I,
|
|
bool *IsWrite,
|
|
uint64_t *TypeSize,
|
|
unsigned *Alignment) {
|
|
// Skip memory accesses inserted by another instrumentation.
|
|
if (I->getMetadata("nosanitize")) return nullptr;
|
|
|
|
Value *PtrOperand = nullptr;
|
|
const DataLayout &DL = I->getModule()->getDataLayout();
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
if (!ClInstrumentReads) return nullptr;
|
|
*IsWrite = false;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(LI->getType());
|
|
*Alignment = LI->getAlignment();
|
|
PtrOperand = LI->getPointerOperand();
|
|
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
|
|
if (!ClInstrumentWrites) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(SI->getValueOperand()->getType());
|
|
*Alignment = SI->getAlignment();
|
|
PtrOperand = SI->getPointerOperand();
|
|
} else if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(RMW->getValOperand()->getType());
|
|
*Alignment = 0;
|
|
PtrOperand = RMW->getPointerOperand();
|
|
} else if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
|
|
if (!ClInstrumentAtomics) return nullptr;
|
|
*IsWrite = true;
|
|
*TypeSize = DL.getTypeStoreSizeInBits(XCHG->getCompareOperand()->getType());
|
|
*Alignment = 0;
|
|
PtrOperand = XCHG->getPointerOperand();
|
|
}
|
|
|
|
// Treat memory accesses to promotable allocas as non-interesting since they
|
|
// will not cause memory violations. This greatly speeds up the instrumented
|
|
// executable at -O0.
|
|
if (ClSkipPromotableAllocas)
|
|
if (auto AI = dyn_cast_or_null<AllocaInst>(PtrOperand))
|
|
return isInterestingAlloca(*AI) ? AI : nullptr;
|
|
|
|
return PtrOperand;
|
|
}
|
|
|
|
static bool isPointerOperand(Value *V) {
|
|
return V->getType()->isPointerTy() || isa<PtrToIntInst>(V);
|
|
}
|
|
|
|
// This is a rough heuristic; it may cause both false positives and
|
|
// false negatives. The proper implementation requires cooperation with
|
|
// the frontend.
|
|
static bool isInterestingPointerComparisonOrSubtraction(Instruction *I) {
|
|
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
|
|
if (!Cmp->isRelational()) return false;
|
|
} else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
if (BO->getOpcode() != Instruction::Sub) return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
if (!isPointerOperand(I->getOperand(0)) ||
|
|
!isPointerOperand(I->getOperand(1)))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
|
|
// If a global variable does not have dynamic initialization we don't
|
|
// have to instrument it. However, if a global does not have initializer
|
|
// at all, we assume it has dynamic initializer (in other TU).
|
|
return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
|
|
}
|
|
|
|
void AddressSanitizer::instrumentPointerComparisonOrSubtraction(
|
|
Instruction *I) {
|
|
IRBuilder<> IRB(I);
|
|
Function *F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
|
|
Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
|
|
for (int i = 0; i < 2; i++) {
|
|
if (Param[i]->getType()->isPointerTy())
|
|
Param[i] = IRB.CreatePointerCast(Param[i], IntptrTy);
|
|
}
|
|
IRB.CreateCall(F, Param);
|
|
}
|
|
|
|
void AddressSanitizer::instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis,
|
|
Instruction *I, bool UseCalls,
|
|
const DataLayout &DL) {
|
|
bool IsWrite = false;
|
|
unsigned Alignment = 0;
|
|
uint64_t TypeSize = 0;
|
|
Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &TypeSize, &Alignment);
|
|
assert(Addr);
|
|
|
|
// Optimization experiments.
|
|
// The experiments can be used to evaluate potential optimizations that remove
|
|
// instrumentation (assess false negatives). Instead of completely removing
|
|
// some instrumentation, you set Exp to a non-zero value (mask of optimization
|
|
// experiments that want to remove instrumentation of this instruction).
|
|
// If Exp is non-zero, this pass will emit special calls into runtime
|
|
// (e.g. __asan_report_exp_load1 instead of __asan_report_load1). These calls
|
|
// make runtime terminate the program in a special way (with a different
|
|
// exit status). Then you run the new compiler on a buggy corpus, collect
|
|
// the special terminations (ideally, you don't see them at all -- no false
|
|
// negatives) and make the decision on the optimization.
|
|
uint32_t Exp = ClForceExperiment;
|
|
|
|
if (ClOpt && ClOptGlobals) {
|
|
// If initialization order checking is disabled, a simple access to a
|
|
// dynamically initialized global is always valid.
|
|
GlobalVariable *G = dyn_cast<GlobalVariable>(GetUnderlyingObject(Addr, DL));
|
|
if (G && (!ClInitializers || GlobalIsLinkerInitialized(G)) &&
|
|
isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
|
|
NumOptimizedAccessesToGlobalVar++;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (ClOpt && ClOptStack) {
|
|
// A direct inbounds access to a stack variable is always valid.
|
|
if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
|
|
isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
|
|
NumOptimizedAccessesToStackVar++;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (IsWrite)
|
|
NumInstrumentedWrites++;
|
|
else
|
|
NumInstrumentedReads++;
|
|
|
|
unsigned Granularity = 1 << Mapping.Scale;
|
|
// Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check
|
|
// if the data is properly aligned.
|
|
if ((TypeSize == 8 || TypeSize == 16 || TypeSize == 32 || TypeSize == 64 ||
|
|
TypeSize == 128) &&
|
|
(Alignment >= Granularity || Alignment == 0 || Alignment >= TypeSize / 8))
|
|
return instrumentAddress(I, I, Addr, TypeSize, IsWrite, nullptr, UseCalls,
|
|
Exp);
|
|
instrumentUnusualSizeOrAlignment(I, Addr, TypeSize, IsWrite, nullptr,
|
|
UseCalls, Exp);
|
|
}
|
|
|
|
Instruction *AddressSanitizer::generateCrashCode(Instruction *InsertBefore,
|
|
Value *Addr, bool IsWrite,
|
|
size_t AccessSizeIndex,
|
|
Value *SizeArgument,
|
|
uint32_t Exp) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *ExpVal = Exp == 0 ? nullptr : ConstantInt::get(IRB.getInt32Ty(), Exp);
|
|
CallInst *Call = nullptr;
|
|
if (SizeArgument) {
|
|
if (Exp == 0)
|
|
Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][0],
|
|
{Addr, SizeArgument});
|
|
else
|
|
Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][1],
|
|
{Addr, SizeArgument, ExpVal});
|
|
} else {
|
|
if (Exp == 0)
|
|
Call =
|
|
IRB.CreateCall(AsanErrorCallback[IsWrite][0][AccessSizeIndex], Addr);
|
|
else
|
|
Call = IRB.CreateCall(AsanErrorCallback[IsWrite][1][AccessSizeIndex],
|
|
{Addr, ExpVal});
|
|
}
|
|
|
|
// We don't do Call->setDoesNotReturn() because the BB already has
|
|
// UnreachableInst at the end.
|
|
// This EmptyAsm is required to avoid callback merge.
|
|
IRB.CreateCall(EmptyAsm, {});
|
|
return Call;
|
|
}
|
|
|
|
Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
|
|
Value *ShadowValue,
|
|
uint32_t TypeSize) {
|
|
size_t Granularity = 1 << Mapping.Scale;
|
|
// Addr & (Granularity - 1)
|
|
Value *LastAccessedByte =
|
|
IRB.CreateAnd(AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
|
|
// (Addr & (Granularity - 1)) + size - 1
|
|
if (TypeSize / 8 > 1)
|
|
LastAccessedByte = IRB.CreateAdd(
|
|
LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
|
|
// (uint8_t) ((Addr & (Granularity-1)) + size - 1)
|
|
LastAccessedByte =
|
|
IRB.CreateIntCast(LastAccessedByte, ShadowValue->getType(), false);
|
|
// ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
|
|
return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
|
|
}
|
|
|
|
void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
|
|
Instruction *InsertBefore, Value *Addr,
|
|
uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls,
|
|
uint32_t Exp) {
|
|
IRBuilder<> IRB(InsertBefore);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
|
|
|
|
if (UseCalls) {
|
|
if (Exp == 0)
|
|
IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][0][AccessSizeIndex],
|
|
AddrLong);
|
|
else
|
|
IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][1][AccessSizeIndex],
|
|
{AddrLong, ConstantInt::get(IRB.getInt32Ty(), Exp)});
|
|
return;
|
|
}
|
|
|
|
Type *ShadowTy =
|
|
IntegerType::get(*C, std::max(8U, TypeSize >> Mapping.Scale));
|
|
Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
|
|
Value *ShadowPtr = memToShadow(AddrLong, IRB);
|
|
Value *CmpVal = Constant::getNullValue(ShadowTy);
|
|
Value *ShadowValue =
|
|
IRB.CreateLoad(IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
|
|
|
|
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
|
|
size_t Granularity = 1 << Mapping.Scale;
|
|
TerminatorInst *CrashTerm = nullptr;
|
|
|
|
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
|
|
// We use branch weights for the slow path check, to indicate that the slow
|
|
// path is rarely taken. This seems to be the case for SPEC benchmarks.
|
|
TerminatorInst *CheckTerm = SplitBlockAndInsertIfThen(
|
|
Cmp, InsertBefore, false, MDBuilder(*C).createBranchWeights(1, 100000));
|
|
assert(cast<BranchInst>(CheckTerm)->isUnconditional());
|
|
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
|
|
IRB.SetInsertPoint(CheckTerm);
|
|
Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
|
|
BasicBlock *CrashBlock =
|
|
BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
|
|
CrashTerm = new UnreachableInst(*C, CrashBlock);
|
|
BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
|
|
ReplaceInstWithInst(CheckTerm, NewTerm);
|
|
} else {
|
|
CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, true);
|
|
}
|
|
|
|
Instruction *Crash = generateCrashCode(CrashTerm, AddrLong, IsWrite,
|
|
AccessSizeIndex, SizeArgument, Exp);
|
|
Crash->setDebugLoc(OrigIns->getDebugLoc());
|
|
}
|
|
|
|
// Instrument unusual size or unusual alignment.
|
|
// We can not do it with a single check, so we do 1-byte check for the first
|
|
// and the last bytes. We call __asan_report_*_n(addr, real_size) to be able
|
|
// to report the actual access size.
|
|
void AddressSanitizer::instrumentUnusualSizeOrAlignment(
|
|
Instruction *I, Value *Addr, uint32_t TypeSize, bool IsWrite,
|
|
Value *SizeArgument, bool UseCalls, uint32_t Exp) {
|
|
IRBuilder<> IRB(I);
|
|
Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
|
|
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
|
|
if (UseCalls) {
|
|
if (Exp == 0)
|
|
IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][0],
|
|
{AddrLong, Size});
|
|
else
|
|
IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][1],
|
|
{AddrLong, Size, ConstantInt::get(IRB.getInt32Ty(), Exp)});
|
|
} else {
|
|
Value *LastByte = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
|
|
Addr->getType());
|
|
instrumentAddress(I, I, Addr, 8, IsWrite, Size, false, Exp);
|
|
instrumentAddress(I, I, LastByte, 8, IsWrite, Size, false, Exp);
|
|
}
|
|
}
|
|
|
|
void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit,
|
|
GlobalValue *ModuleName) {
|
|
// Set up the arguments to our poison/unpoison functions.
|
|
IRBuilder<> IRB(GlobalInit.begin()->getFirstInsertionPt());
|
|
|
|
// Add a call to poison all external globals before the given function starts.
|
|
Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
|
|
IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr);
|
|
|
|
// Add calls to unpoison all globals before each return instruction.
|
|
for (auto &BB : GlobalInit.getBasicBlockList())
|
|
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator()))
|
|
CallInst::Create(AsanUnpoisonGlobals, "", RI);
|
|
}
|
|
|
|
void AddressSanitizerModule::createInitializerPoisonCalls(
|
|
Module &M, GlobalValue *ModuleName) {
|
|
GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
|
|
|
|
ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
|
|
for (Use &OP : CA->operands()) {
|
|
if (isa<ConstantAggregateZero>(OP)) continue;
|
|
ConstantStruct *CS = cast<ConstantStruct>(OP);
|
|
|
|
// Must have a function or null ptr.
|
|
if (Function *F = dyn_cast<Function>(CS->getOperand(1))) {
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
|
|
Type *Ty = cast<PointerType>(G->getType())->getElementType();
|
|
DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
|
|
|
|
if (GlobalsMD.get(G).IsBlacklisted) return false;
|
|
if (!Ty->isSized()) return false;
|
|
if (!G->hasInitializer()) return false;
|
|
if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
|
|
// Touch only those globals that will not be defined in other modules.
|
|
// Don't handle ODR linkage types and COMDATs since other modules may be built
|
|
// without ASan.
|
|
if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
|
|
G->getLinkage() != GlobalVariable::PrivateLinkage &&
|
|
G->getLinkage() != GlobalVariable::InternalLinkage)
|
|
return false;
|
|
if (G->hasComdat()) return false;
|
|
// Two problems with thread-locals:
|
|
// - The address of the main thread's copy can't be computed at link-time.
|
|
// - Need to poison all copies, not just the main thread's one.
|
|
if (G->isThreadLocal()) return false;
|
|
// For now, just ignore this Global if the alignment is large.
|
|
if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
|
|
|
|
if (G->hasSection()) {
|
|
StringRef Section(G->getSection());
|
|
|
|
// Globals from llvm.metadata aren't emitted, do not instrument them.
|
|
if (Section == "llvm.metadata") return false;
|
|
// Do not instrument globals from special LLVM sections.
|
|
if (Section.find("__llvm") != StringRef::npos) return false;
|
|
|
|
// Do not instrument function pointers to initialization and termination
|
|
// routines: dynamic linker will not properly handle redzones.
|
|
if (Section.startswith(".preinit_array") ||
|
|
Section.startswith(".init_array") ||
|
|
Section.startswith(".fini_array")) {
|
|
return false;
|
|
}
|
|
|
|
// Callbacks put into the CRT initializer/terminator sections
|
|
// should not be instrumented.
|
|
// See https://code.google.com/p/address-sanitizer/issues/detail?id=305
|
|
// and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
|
|
if (Section.startswith(".CRT")) {
|
|
DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
|
|
return false;
|
|
}
|
|
|
|
if (TargetTriple.isOSBinFormatMachO()) {
|
|
StringRef ParsedSegment, ParsedSection;
|
|
unsigned TAA = 0, StubSize = 0;
|
|
bool TAAParsed;
|
|
std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(
|
|
Section, ParsedSegment, ParsedSection, TAA, TAAParsed, StubSize);
|
|
if (!ErrorCode.empty()) {
|
|
assert(false && "Invalid section specifier.");
|
|
return false;
|
|
}
|
|
|
|
// Ignore the globals from the __OBJC section. The ObjC runtime assumes
|
|
// those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
|
|
// them.
|
|
if (ParsedSegment == "__OBJC" ||
|
|
(ParsedSegment == "__DATA" && ParsedSection.startswith("__objc_"))) {
|
|
DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// See http://code.google.com/p/address-sanitizer/issues/detail?id=32
|
|
// Constant CFString instances are compiled in the following way:
|
|
// -- the string buffer is emitted into
|
|
// __TEXT,__cstring,cstring_literals
|
|
// -- the constant NSConstantString structure referencing that buffer
|
|
// is placed into __DATA,__cfstring
|
|
// Therefore there's no point in placing redzones into __DATA,__cfstring.
|
|
// Moreover, it causes the linker to crash on OS X 10.7
|
|
if (ParsedSegment == "__DATA" && ParsedSection == "__cfstring") {
|
|
DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
|
|
return false;
|
|
}
|
|
// The linker merges the contents of cstring_literals and removes the
|
|
// trailing zeroes.
|
|
if (ParsedSegment == "__TEXT" && (TAA & MachO::S_CSTRING_LITERALS)) {
|
|
DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void AddressSanitizerModule::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
// Declare our poisoning and unpoisoning functions.
|
|
AsanPoisonGlobals = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, nullptr));
|
|
AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
|
|
AsanUnpoisonGlobals = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanUnpoisonGlobalsName, IRB.getVoidTy(), nullptr));
|
|
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
|
|
// Declare functions that register/unregister globals.
|
|
AsanRegisterGlobals = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanRegisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
|
|
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
|
|
AsanUnregisterGlobals = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanUnregisterGlobalsName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, nullptr));
|
|
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
|
|
}
|
|
|
|
// This function replaces all global variables with new variables that have
|
|
// trailing redzones. It also creates a function that poisons
|
|
// redzones and inserts this function into llvm.global_ctors.
|
|
bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
|
|
GlobalsMD.init(M);
|
|
|
|
SmallVector<GlobalVariable *, 16> GlobalsToChange;
|
|
|
|
for (auto &G : M.globals()) {
|
|
if (ShouldInstrumentGlobal(&G)) GlobalsToChange.push_back(&G);
|
|
}
|
|
|
|
size_t n = GlobalsToChange.size();
|
|
if (n == 0) return false;
|
|
|
|
// A global is described by a structure
|
|
// size_t beg;
|
|
// size_t size;
|
|
// size_t size_with_redzone;
|
|
// const char *name;
|
|
// const char *module_name;
|
|
// size_t has_dynamic_init;
|
|
// void *source_location;
|
|
// 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, nullptr);
|
|
SmallVector<Constant *, 16> Initializers(n);
|
|
|
|
bool HasDynamicallyInitializedGlobals = false;
|
|
|
|
// We shouldn't merge same module names, as this string serves as unique
|
|
// module ID in runtime.
|
|
GlobalVariable *ModuleName = createPrivateGlobalForString(
|
|
M, M.getModuleIdentifier(), /*AllowMerging*/ false);
|
|
|
|
auto &DL = M.getDataLayout();
|
|
for (size_t i = 0; i < n; i++) {
|
|
static const uint64_t kMaxGlobalRedzone = 1 << 18;
|
|
GlobalVariable *G = GlobalsToChange[i];
|
|
|
|
auto MD = GlobalsMD.get(G);
|
|
// Create string holding the global name (use global name from metadata
|
|
// if it's available, otherwise just write the name of global variable).
|
|
GlobalVariable *Name = createPrivateGlobalForString(
|
|
M, MD.Name.empty() ? G->getName() : MD.Name,
|
|
/*AllowMerging*/ true);
|
|
|
|
PointerType *PtrTy = cast<PointerType>(G->getType());
|
|
Type *Ty = PtrTy->getElementType();
|
|
uint64_t SizeInBytes = DL.getTypeAllocSize(Ty);
|
|
uint64_t MinRZ = MinRedzoneSizeForGlobal();
|
|
// MinRZ <= RZ <= kMaxGlobalRedzone
|
|
// and trying to make RZ to be ~ 1/4 of SizeInBytes.
|
|
uint64_t RZ = std::max(
|
|
MinRZ, std::min(kMaxGlobalRedzone, (SizeInBytes / MinRZ / 4) * MinRZ));
|
|
uint64_t RightRedzoneSize = RZ;
|
|
// Round up to MinRZ
|
|
if (SizeInBytes % MinRZ) RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
|
|
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
|
|
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
|
|
|
|
StructType *NewTy = StructType::get(Ty, RightRedZoneTy, nullptr);
|
|
Constant *NewInitializer =
|
|
ConstantStruct::get(NewTy, G->getInitializer(),
|
|
Constant::getNullValue(RightRedZoneTy), nullptr);
|
|
|
|
// Create a new global variable with enough space for a redzone.
|
|
GlobalValue::LinkageTypes Linkage = G->getLinkage();
|
|
if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
|
|
Linkage = GlobalValue::InternalLinkage;
|
|
GlobalVariable *NewGlobal =
|
|
new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer,
|
|
"", G, G->getThreadLocalMode());
|
|
NewGlobal->copyAttributesFrom(G);
|
|
NewGlobal->setAlignment(MinRZ);
|
|
|
|
Value *Indices2[2];
|
|
Indices2[0] = IRB.getInt32(0);
|
|
Indices2[1] = IRB.getInt32(0);
|
|
|
|
G->replaceAllUsesWith(
|
|
ConstantExpr::getGetElementPtr(NewTy, NewGlobal, Indices2, true));
|
|
NewGlobal->takeName(G);
|
|
G->eraseFromParent();
|
|
|
|
Constant *SourceLoc;
|
|
if (!MD.SourceLoc.empty()) {
|
|
auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc);
|
|
SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy);
|
|
} else {
|
|
SourceLoc = ConstantInt::get(IntptrTy, 0);
|
|
}
|
|
|
|
Initializers[i] = ConstantStruct::get(
|
|
GlobalStructTy, ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
|
|
ConstantInt::get(IntptrTy, SizeInBytes),
|
|
ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
|
|
ConstantExpr::getPointerCast(Name, IntptrTy),
|
|
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
|
|
ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, nullptr);
|
|
|
|
if (ClInitializers && MD.IsDynInit) HasDynamicallyInitializedGlobals = true;
|
|
|
|
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
|
|
}
|
|
|
|
ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
|
|
GlobalVariable *AllGlobals = new GlobalVariable(
|
|
M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
|
|
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
|
|
|
|
// Create calls for poisoning before initializers run and unpoisoning after.
|
|
if (HasDynamicallyInitializedGlobals)
|
|
createInitializerPoisonCalls(M, ModuleName);
|
|
IRB.CreateCall(AsanRegisterGlobals,
|
|
{IRB.CreatePointerCast(AllGlobals, IntptrTy),
|
|
ConstantInt::get(IntptrTy, n)});
|
|
|
|
// We also need to unregister globals at the end, e.g. when a shared library
|
|
// gets closed.
|
|
Function *AsanDtorFunction =
|
|
Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
|
|
GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
|
|
BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
|
|
IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
|
|
IRB_Dtor.CreateCall(AsanUnregisterGlobals,
|
|
{IRB.CreatePointerCast(AllGlobals, IntptrTy),
|
|
ConstantInt::get(IntptrTy, n)});
|
|
appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
|
|
|
|
DEBUG(dbgs() << M);
|
|
return true;
|
|
}
|
|
|
|
bool AddressSanitizerModule::runOnModule(Module &M) {
|
|
C = &(M.getContext());
|
|
int LongSize = M.getDataLayout().getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
TargetTriple = Triple(M.getTargetTriple());
|
|
Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
|
|
initializeCallbacks(M);
|
|
|
|
bool Changed = false;
|
|
|
|
// TODO(glider): temporarily disabled globals instrumentation for KASan.
|
|
if (ClGlobals && !CompileKernel) {
|
|
Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
|
|
assert(CtorFunc);
|
|
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
|
|
Changed |= InstrumentGlobals(IRB, M);
|
|
}
|
|
|
|
return Changed;
|
|
}
|
|
|
|
void AddressSanitizer::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
// Create __asan_report* callbacks.
|
|
// IsWrite, TypeSize and Exp are encoded in the function name.
|
|
for (int Exp = 0; Exp < 2; Exp++) {
|
|
for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
|
|
const std::string TypeStr = AccessIsWrite ? "store" : "load";
|
|
const std::string ExpStr = Exp ? "exp_" : "";
|
|
const std::string SuffixStr = CompileKernel ? "N" : "_n";
|
|
const std::string EndingStr = CompileKernel ? "_noabort" : "";
|
|
Type *ExpType = Exp ? Type::getInt32Ty(*C) : nullptr;
|
|
// TODO(glider): for KASan builds add _noabort to error reporting
|
|
// functions and make them actually noabort (remove the UnreachableInst).
|
|
AsanErrorCallbackSized[AccessIsWrite][Exp] =
|
|
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanReportErrorTemplate + ExpStr + TypeStr + SuffixStr,
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, ExpType, nullptr));
|
|
AsanMemoryAccessCallbackSized[AccessIsWrite][Exp] =
|
|
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + ExpStr + TypeStr + "N" + EndingStr,
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, ExpType, nullptr));
|
|
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
|
|
AccessSizeIndex++) {
|
|
const std::string Suffix = TypeStr + itostr(1 << AccessSizeIndex);
|
|
AsanErrorCallback[AccessIsWrite][Exp][AccessSizeIndex] =
|
|
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanReportErrorTemplate + ExpStr + Suffix,
|
|
IRB.getVoidTy(), IntptrTy, ExpType, nullptr));
|
|
AsanMemoryAccessCallback[AccessIsWrite][Exp][AccessSizeIndex] =
|
|
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
ClMemoryAccessCallbackPrefix + ExpStr + Suffix + EndingStr,
|
|
IRB.getVoidTy(), IntptrTy, ExpType, nullptr));
|
|
}
|
|
}
|
|
}
|
|
|
|
const std::string MemIntrinCallbackPrefix =
|
|
CompileKernel ? std::string("") : ClMemoryAccessCallbackPrefix;
|
|
AsanMemmove = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
MemIntrinCallbackPrefix + "memmove", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
|
|
AsanMemcpy = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
MemIntrinCallbackPrefix + "memcpy", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
|
|
AsanMemset = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
MemIntrinCallbackPrefix + "memset", IRB.getInt8PtrTy(),
|
|
IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, nullptr));
|
|
|
|
AsanHandleNoReturnFunc = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), nullptr));
|
|
|
|
AsanPtrCmpFunction = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
|
|
AsanPtrSubFunction = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
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(""),
|
|
/*hasSideEffects=*/true);
|
|
}
|
|
|
|
// virtual
|
|
bool AddressSanitizer::doInitialization(Module &M) {
|
|
// Initialize the private fields. No one has accessed them before.
|
|
|
|
GlobalsMD.init(M);
|
|
|
|
C = &(M.getContext());
|
|
LongSize = M.getDataLayout().getPointerSizeInBits();
|
|
IntptrTy = Type::getIntNTy(*C, LongSize);
|
|
TargetTriple = Triple(M.getTargetTriple());
|
|
|
|
if (!CompileKernel) {
|
|
std::tie(AsanCtorFunction, AsanInitFunction) =
|
|
createSanitizerCtorAndInitFunctions(
|
|
M, kAsanModuleCtorName, kAsanInitName,
|
|
/*InitArgTypes=*/{}, /*InitArgs=*/{}, kAsanVersionCheckName);
|
|
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
|
|
}
|
|
Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
|
|
return true;
|
|
}
|
|
|
|
bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
|
|
// For each NSObject descendant having a +load method, this method is invoked
|
|
// by the ObjC runtime before any of the static constructors is called.
|
|
// Therefore we need to instrument such methods with a call to __asan_init
|
|
// at the beginning in order to initialize our runtime before any access to
|
|
// the shadow memory.
|
|
// We cannot just ignore these methods, because they may call other
|
|
// instrumented functions.
|
|
if (F.getName().find(" load]") != std::string::npos) {
|
|
IRBuilder<> IRB(F.begin()->begin());
|
|
IRB.CreateCall(AsanInitFunction, {});
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
|
|
// Find the one possible call to llvm.localescape and pre-mark allocas passed
|
|
// to it as uninteresting. This assumes we haven't started processing allocas
|
|
// yet. This check is done up front because iterating the use list in
|
|
// isInterestingAlloca would be algorithmically slower.
|
|
assert(ProcessedAllocas.empty() && "must process localescape before allocas");
|
|
|
|
// Try to get the declaration of llvm.localescape. If it's not in the module,
|
|
// we can exit early.
|
|
if (!F.getParent()->getFunction("llvm.localescape")) return;
|
|
|
|
// Look for a call to llvm.localescape call in the entry block. It can't be in
|
|
// any other block.
|
|
for (Instruction &I : F.getEntryBlock()) {
|
|
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (II && II->getIntrinsicID() == Intrinsic::localescape) {
|
|
// We found a call. Mark all the allocas passed in as uninteresting.
|
|
for (Value *Arg : II->arg_operands()) {
|
|
AllocaInst *AI = dyn_cast<AllocaInst>(Arg->stripPointerCasts());
|
|
assert(AI && AI->isStaticAlloca() &&
|
|
"non-static alloca arg to localescape");
|
|
ProcessedAllocas[AI] = false;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
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 (!F.hasFnAttribute(Attribute::SanitizeAddress)) return false;
|
|
|
|
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName()) return false;
|
|
|
|
FunctionStateRAII CleanupObj(this);
|
|
|
|
// We can't instrument allocas used with llvm.localescape. Only static allocas
|
|
// can be passed to that intrinsic.
|
|
markEscapedLocalAllocas(F);
|
|
|
|
// We want to instrument every address only once per basic block (unless there
|
|
// are calls between uses).
|
|
SmallSet<Value *, 16> TempsToInstrument;
|
|
SmallVector<Instruction *, 16> ToInstrument;
|
|
SmallVector<Instruction *, 8> NoReturnCalls;
|
|
SmallVector<BasicBlock *, 16> AllBlocks;
|
|
SmallVector<Instruction *, 16> PointerComparisonsOrSubtracts;
|
|
int NumAllocas = 0;
|
|
bool IsWrite;
|
|
unsigned Alignment;
|
|
uint64_t TypeSize;
|
|
|
|
// Fill the set of memory operations to instrument.
|
|
for (auto &BB : F) {
|
|
AllBlocks.push_back(&BB);
|
|
TempsToInstrument.clear();
|
|
int NumInsnsPerBB = 0;
|
|
for (auto &Inst : BB) {
|
|
if (LooksLikeCodeInBug11395(&Inst)) return false;
|
|
if (Value *Addr = isInterestingMemoryAccess(&Inst, &IsWrite, &TypeSize,
|
|
&Alignment)) {
|
|
if (ClOpt && ClOptSameTemp) {
|
|
if (!TempsToInstrument.insert(Addr).second)
|
|
continue; // We've seen this temp in the current BB.
|
|
}
|
|
} else if (ClInvalidPointerPairs &&
|
|
isInterestingPointerComparisonOrSubtraction(&Inst)) {
|
|
PointerComparisonsOrSubtracts.push_back(&Inst);
|
|
continue;
|
|
} else if (isa<MemIntrinsic>(Inst)) {
|
|
// ok, take it.
|
|
} else {
|
|
if (isa<AllocaInst>(Inst)) NumAllocas++;
|
|
CallSite CS(&Inst);
|
|
if (CS) {
|
|
// A call inside BB.
|
|
TempsToInstrument.clear();
|
|
if (CS.doesNotReturn()) NoReturnCalls.push_back(CS.getInstruction());
|
|
}
|
|
continue;
|
|
}
|
|
ToInstrument.push_back(&Inst);
|
|
NumInsnsPerBB++;
|
|
if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) break;
|
|
}
|
|
}
|
|
|
|
bool UseCalls =
|
|
CompileKernel ||
|
|
(ClInstrumentationWithCallsThreshold >= 0 &&
|
|
ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold);
|
|
const TargetLibraryInfo *TLI =
|
|
&getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
|
|
const DataLayout &DL = F.getParent()->getDataLayout();
|
|
ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(),
|
|
/*RoundToAlign=*/true);
|
|
|
|
// Instrument.
|
|
int NumInstrumented = 0;
|
|
for (auto Inst : ToInstrument) {
|
|
if (ClDebugMin < 0 || ClDebugMax < 0 ||
|
|
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
|
|
if (isInterestingMemoryAccess(Inst, &IsWrite, &TypeSize, &Alignment))
|
|
instrumentMop(ObjSizeVis, Inst, UseCalls,
|
|
F.getParent()->getDataLayout());
|
|
else
|
|
instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
|
|
}
|
|
NumInstrumented++;
|
|
}
|
|
|
|
FunctionStackPoisoner FSP(F, *this);
|
|
bool ChangedStack = FSP.runOnFunction();
|
|
|
|
// We must unpoison the stack before every NoReturn call (throw, _exit, etc).
|
|
// See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
|
|
for (auto CI : NoReturnCalls) {
|
|
IRBuilder<> IRB(CI);
|
|
IRB.CreateCall(AsanHandleNoReturnFunc, {});
|
|
}
|
|
|
|
for (auto Inst : PointerComparisonsOrSubtracts) {
|
|
instrumentPointerComparisonOrSubtraction(Inst);
|
|
NumInstrumented++;
|
|
}
|
|
|
|
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
|
|
|
|
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
|
|
|
|
return res;
|
|
}
|
|
|
|
// Workaround for bug 11395: we don't want to instrument stack in functions
|
|
// with large assembly blobs (32-bit only), otherwise reg alloc may crash.
|
|
// FIXME: remove once the bug 11395 is fixed.
|
|
bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
|
|
if (LongSize != 32) return false;
|
|
CallInst *CI = dyn_cast<CallInst>(I);
|
|
if (!CI || !CI->isInlineAsm()) return false;
|
|
if (CI->getNumArgOperands() <= 5) return false;
|
|
// We have inline assembly with quite a few arguments.
|
|
return true;
|
|
}
|
|
|
|
void FunctionStackPoisoner::initializeCallbacks(Module &M) {
|
|
IRBuilder<> IRB(*C);
|
|
for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) {
|
|
std::string Suffix = itostr(i);
|
|
AsanStackMallocFunc[i] = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
|
|
IntptrTy, nullptr));
|
|
AsanStackFreeFunc[i] = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanStackFreeNameTemplate + Suffix,
|
|
IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
|
|
}
|
|
AsanPoisonStackMemoryFunc = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanPoisonStackMemoryName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, nullptr));
|
|
AsanUnpoisonStackMemoryFunc = checkSanitizerInterfaceFunction(
|
|
M.getOrInsertFunction(kAsanUnpoisonStackMemoryName, IRB.getVoidTy(),
|
|
IntptrTy, IntptrTy, nullptr));
|
|
AsanAllocaPoisonFunc = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanAllocaPoison, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
|
|
AsanAllocasUnpoisonFunc =
|
|
checkSanitizerInterfaceFunction(M.getOrInsertFunction(
|
|
kAsanAllocasUnpoison, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonRedZones(ArrayRef<uint8_t> ShadowBytes,
|
|
IRBuilder<> &IRB, Value *ShadowBase,
|
|
bool DoPoison) {
|
|
size_t n = ShadowBytes.size();
|
|
size_t i = 0;
|
|
// We need to (un)poison n bytes of stack shadow. Poison as many as we can
|
|
// using 64-bit stores (if we are on 64-bit arch), then poison the rest
|
|
// with 32-bit stores, then with 16-byte stores, then with 8-byte stores.
|
|
for (size_t LargeStoreSizeInBytes = ASan.LongSize / 8;
|
|
LargeStoreSizeInBytes != 0; LargeStoreSizeInBytes /= 2) {
|
|
for (; i + LargeStoreSizeInBytes - 1 < n; i += LargeStoreSizeInBytes) {
|
|
uint64_t Val = 0;
|
|
for (size_t j = 0; j < LargeStoreSizeInBytes; j++) {
|
|
if (F.getParent()->getDataLayout().isLittleEndian())
|
|
Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
|
|
else
|
|
Val = (Val << 8) | ShadowBytes[i + j];
|
|
}
|
|
if (!Val) continue;
|
|
Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
|
|
Type *StoreTy = Type::getIntNTy(*C, LargeStoreSizeInBytes * 8);
|
|
Value *Poison = ConstantInt::get(StoreTy, DoPoison ? Val : 0);
|
|
IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, StoreTy->getPointerTo()));
|
|
}
|
|
}
|
|
}
|
|
|
|
// Fake stack allocator (asan_fake_stack.h) has 11 size classes
|
|
// for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass
|
|
static int StackMallocSizeClass(uint64_t LocalStackSize) {
|
|
assert(LocalStackSize <= kMaxStackMallocSize);
|
|
uint64_t MaxSize = kMinStackMallocSize;
|
|
for (int i = 0;; i++, MaxSize *= 2)
|
|
if (LocalStackSize <= MaxSize) return i;
|
|
llvm_unreachable("impossible LocalStackSize");
|
|
}
|
|
|
|
// Set Size bytes starting from ShadowBase to kAsanStackAfterReturnMagic.
|
|
// We can not use MemSet intrinsic because it may end up calling the actual
|
|
// memset. Size is a multiple of 8.
|
|
// Currently this generates 8-byte stores on x86_64; it may be better to
|
|
// generate wider stores.
|
|
void FunctionStackPoisoner::SetShadowToStackAfterReturnInlined(
|
|
IRBuilder<> &IRB, Value *ShadowBase, int Size) {
|
|
assert(!(Size % 8));
|
|
|
|
// kAsanStackAfterReturnMagic is 0xf5.
|
|
const uint64_t kAsanStackAfterReturnMagic64 = 0xf5f5f5f5f5f5f5f5ULL;
|
|
|
|
for (int i = 0; i < Size; i += 8) {
|
|
Value *p = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
|
|
IRB.CreateStore(
|
|
ConstantInt::get(IRB.getInt64Ty(), kAsanStackAfterReturnMagic64),
|
|
IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo()));
|
|
}
|
|
}
|
|
|
|
PHINode *FunctionStackPoisoner::createPHI(IRBuilder<> &IRB, Value *Cond,
|
|
Value *ValueIfTrue,
|
|
Instruction *ThenTerm,
|
|
Value *ValueIfFalse) {
|
|
PHINode *PHI = IRB.CreatePHI(IntptrTy, 2);
|
|
BasicBlock *CondBlock = cast<Instruction>(Cond)->getParent();
|
|
PHI->addIncoming(ValueIfFalse, CondBlock);
|
|
BasicBlock *ThenBlock = ThenTerm->getParent();
|
|
PHI->addIncoming(ValueIfTrue, ThenBlock);
|
|
return PHI;
|
|
}
|
|
|
|
Value *FunctionStackPoisoner::createAllocaForLayout(
|
|
IRBuilder<> &IRB, const ASanStackFrameLayout &L, bool Dynamic) {
|
|
AllocaInst *Alloca;
|
|
if (Dynamic) {
|
|
Alloca = IRB.CreateAlloca(IRB.getInt8Ty(),
|
|
ConstantInt::get(IRB.getInt64Ty(), L.FrameSize),
|
|
"MyAlloca");
|
|
} else {
|
|
Alloca = IRB.CreateAlloca(ArrayType::get(IRB.getInt8Ty(), L.FrameSize),
|
|
nullptr, "MyAlloca");
|
|
assert(Alloca->isStaticAlloca());
|
|
}
|
|
assert((ClRealignStack & (ClRealignStack - 1)) == 0);
|
|
size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
|
|
Alloca->setAlignment(FrameAlignment);
|
|
return IRB.CreatePointerCast(Alloca, IntptrTy);
|
|
}
|
|
|
|
void FunctionStackPoisoner::createDynamicAllocasInitStorage() {
|
|
BasicBlock &FirstBB = *F.begin();
|
|
IRBuilder<> IRB(dyn_cast<Instruction>(FirstBB.begin()));
|
|
DynamicAllocaLayout = IRB.CreateAlloca(IntptrTy, nullptr);
|
|
IRB.CreateStore(Constant::getNullValue(IntptrTy), DynamicAllocaLayout);
|
|
DynamicAllocaLayout->setAlignment(32);
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonStack() {
|
|
assert(AllocaVec.size() > 0 || DynamicAllocaVec.size() > 0);
|
|
|
|
if (ClInstrumentAllocas && DynamicAllocaVec.size() > 0) {
|
|
// Handle dynamic allocas.
|
|
createDynamicAllocasInitStorage();
|
|
for (auto &AI : DynamicAllocaVec) handleDynamicAllocaCall(AI);
|
|
|
|
unpoisonDynamicAllocas();
|
|
}
|
|
|
|
if (AllocaVec.empty()) return;
|
|
|
|
int StackMallocIdx = -1;
|
|
DebugLoc EntryDebugLocation;
|
|
if (auto SP = getDISubprogram(&F))
|
|
EntryDebugLocation = DebugLoc::get(SP->getScopeLine(), 0, SP);
|
|
|
|
Instruction *InsBefore = AllocaVec[0];
|
|
IRBuilder<> IRB(InsBefore);
|
|
IRB.SetCurrentDebugLocation(EntryDebugLocation);
|
|
|
|
// Make sure non-instrumented allocas stay in the entry block. Otherwise,
|
|
// debug info is broken, because only entry-block allocas are treated as
|
|
// regular stack slots.
|
|
auto InsBeforeB = InsBefore->getParent();
|
|
assert(InsBeforeB == &F.getEntryBlock());
|
|
for (BasicBlock::iterator I = InsBefore; I != InsBeforeB->end(); ++I)
|
|
if (auto *AI = dyn_cast_or_null<AllocaInst>(I))
|
|
if (NonInstrumentedStaticAllocaVec.count(AI) > 0)
|
|
AI->moveBefore(InsBefore);
|
|
|
|
// If we have a call to llvm.localescape, keep it in the entry block.
|
|
if (LocalEscapeCall) LocalEscapeCall->moveBefore(InsBefore);
|
|
|
|
SmallVector<ASanStackVariableDescription, 16> SVD;
|
|
SVD.reserve(AllocaVec.size());
|
|
for (AllocaInst *AI : AllocaVec) {
|
|
ASanStackVariableDescription D = {AI->getName().data(),
|
|
ASan.getAllocaSizeInBytes(AI),
|
|
AI->getAlignment(), AI, 0};
|
|
SVD.push_back(D);
|
|
}
|
|
// Minimal header size (left redzone) is 4 pointers,
|
|
// i.e. 32 bytes on 64-bit platforms and 16 bytes in 32-bit platforms.
|
|
size_t MinHeaderSize = ASan.LongSize / 2;
|
|
ASanStackFrameLayout L;
|
|
ComputeASanStackFrameLayout(SVD, 1UL << Mapping.Scale, MinHeaderSize, &L);
|
|
DEBUG(dbgs() << L.DescriptionString << " --- " << L.FrameSize << "\n");
|
|
uint64_t LocalStackSize = L.FrameSize;
|
|
bool DoStackMalloc = ClUseAfterReturn && !ASan.CompileKernel &&
|
|
LocalStackSize <= kMaxStackMallocSize;
|
|
bool DoDynamicAlloca = ClDynamicAllocaStack;
|
|
// Don't do dynamic alloca or stack malloc if:
|
|
// 1) There is inline asm: too often it makes assumptions on which registers
|
|
// are available.
|
|
// 2) There is a returns_twice call (typically setjmp), which is
|
|
// optimization-hostile, and doesn't play well with introduced indirect
|
|
// register-relative calculation of local variable addresses.
|
|
DoDynamicAlloca &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
|
|
DoStackMalloc &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
|
|
|
|
Value *StaticAlloca =
|
|
DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);
|
|
|
|
Value *FakeStack;
|
|
Value *LocalStackBase;
|
|
|
|
if (DoStackMalloc) {
|
|
// void *FakeStack = __asan_option_detect_stack_use_after_return
|
|
// ? __asan_stack_malloc_N(LocalStackSize)
|
|
// : nullptr;
|
|
// void *LocalStackBase = (FakeStack) ? FakeStack : alloca(LocalStackSize);
|
|
Constant *OptionDetectUAR = F.getParent()->getOrInsertGlobal(
|
|
kAsanOptionDetectUAR, IRB.getInt32Ty());
|
|
Value *UARIsEnabled =
|
|
IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR),
|
|
Constant::getNullValue(IRB.getInt32Ty()));
|
|
Instruction *Term =
|
|
SplitBlockAndInsertIfThen(UARIsEnabled, InsBefore, false);
|
|
IRBuilder<> IRBIf(Term);
|
|
IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
|
|
StackMallocIdx = StackMallocSizeClass(LocalStackSize);
|
|
assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
|
|
Value *FakeStackValue =
|
|
IRBIf.CreateCall(AsanStackMallocFunc[StackMallocIdx],
|
|
ConstantInt::get(IntptrTy, LocalStackSize));
|
|
IRB.SetInsertPoint(InsBefore);
|
|
IRB.SetCurrentDebugLocation(EntryDebugLocation);
|
|
FakeStack = createPHI(IRB, UARIsEnabled, FakeStackValue, Term,
|
|
ConstantInt::get(IntptrTy, 0));
|
|
|
|
Value *NoFakeStack =
|
|
IRB.CreateICmpEQ(FakeStack, Constant::getNullValue(IntptrTy));
|
|
Term = SplitBlockAndInsertIfThen(NoFakeStack, InsBefore, false);
|
|
IRBIf.SetInsertPoint(Term);
|
|
IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
|
|
Value *AllocaValue =
|
|
DoDynamicAlloca ? createAllocaForLayout(IRBIf, L, true) : StaticAlloca;
|
|
IRB.SetInsertPoint(InsBefore);
|
|
IRB.SetCurrentDebugLocation(EntryDebugLocation);
|
|
LocalStackBase = createPHI(IRB, NoFakeStack, AllocaValue, Term, FakeStack);
|
|
} else {
|
|
// void *FakeStack = nullptr;
|
|
// void *LocalStackBase = alloca(LocalStackSize);
|
|
FakeStack = ConstantInt::get(IntptrTy, 0);
|
|
LocalStackBase =
|
|
DoDynamicAlloca ? createAllocaForLayout(IRB, L, true) : StaticAlloca;
|
|
}
|
|
|
|
// Insert poison calls for lifetime intrinsics for alloca.
|
|
bool HavePoisonedAllocas = false;
|
|
for (const auto &APC : AllocaPoisonCallVec) {
|
|
assert(APC.InsBefore);
|
|
assert(APC.AI);
|
|
IRBuilder<> IRB(APC.InsBefore);
|
|
poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
|
|
HavePoisonedAllocas |= APC.DoPoison;
|
|
}
|
|
|
|
// Replace Alloca instructions with base+offset.
|
|
for (const auto &Desc : SVD) {
|
|
AllocaInst *AI = Desc.AI;
|
|
Value *NewAllocaPtr = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
|
|
AI->getType());
|
|
replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB, /*Deref=*/true);
|
|
AI->replaceAllUsesWith(NewAllocaPtr);
|
|
}
|
|
|
|
// The left-most redzone has enough space for at least 4 pointers.
|
|
// Write the Magic value to redzone[0].
|
|
Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
|
|
IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
|
|
BasePlus0);
|
|
// Write the frame description constant to redzone[1].
|
|
Value *BasePlus1 = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase,
|
|
ConstantInt::get(IntptrTy, ASan.LongSize / 8)),
|
|
IntptrPtrTy);
|
|
GlobalVariable *StackDescriptionGlobal =
|
|
createPrivateGlobalForString(*F.getParent(), L.DescriptionString,
|
|
/*AllowMerging*/ true);
|
|
Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
|
|
IRB.CreateStore(Description, BasePlus1);
|
|
// Write the PC to redzone[2].
|
|
Value *BasePlus2 = IRB.CreateIntToPtr(
|
|
IRB.CreateAdd(LocalStackBase,
|
|
ConstantInt::get(IntptrTy, 2 * ASan.LongSize / 8)),
|
|
IntptrPtrTy);
|
|
IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2);
|
|
|
|
// Poison the stack redzones at the entry.
|
|
Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
|
|
poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true);
|
|
|
|
// (Un)poison the stack before all ret instructions.
|
|
for (auto Ret : RetVec) {
|
|
IRBuilder<> IRBRet(Ret);
|
|
// Mark the current frame as retired.
|
|
IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
|
|
BasePlus0);
|
|
if (DoStackMalloc) {
|
|
assert(StackMallocIdx >= 0);
|
|
// if FakeStack != 0 // LocalStackBase == FakeStack
|
|
// // In use-after-return mode, poison the whole stack frame.
|
|
// if StackMallocIdx <= 4
|
|
// // For small sizes inline the whole thing:
|
|
// memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize);
|
|
// **SavedFlagPtr(FakeStack) = 0
|
|
// else
|
|
// __asan_stack_free_N(FakeStack, LocalStackSize)
|
|
// else
|
|
// <This is not a fake stack; unpoison the redzones>
|
|
Value *Cmp =
|
|
IRBRet.CreateICmpNE(FakeStack, Constant::getNullValue(IntptrTy));
|
|
TerminatorInst *ThenTerm, *ElseTerm;
|
|
SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
|
|
|
|
IRBuilder<> IRBPoison(ThenTerm);
|
|
if (StackMallocIdx <= 4) {
|
|
int ClassSize = kMinStackMallocSize << StackMallocIdx;
|
|
SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase,
|
|
ClassSize >> Mapping.Scale);
|
|
Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
|
|
FakeStack,
|
|
ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
|
|
Value *SavedFlagPtr = IRBPoison.CreateLoad(
|
|
IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
|
|
IRBPoison.CreateStore(
|
|
Constant::getNullValue(IRBPoison.getInt8Ty()),
|
|
IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
|
|
} else {
|
|
// For larger frames call __asan_stack_free_*.
|
|
IRBPoison.CreateCall(
|
|
AsanStackFreeFunc[StackMallocIdx],
|
|
{FakeStack, ConstantInt::get(IntptrTy, LocalStackSize)});
|
|
}
|
|
|
|
IRBuilder<> IRBElse(ElseTerm);
|
|
poisonRedZones(L.ShadowBytes, IRBElse, ShadowBase, false);
|
|
} else if (HavePoisonedAllocas) {
|
|
// If we poisoned some allocas in llvm.lifetime analysis,
|
|
// unpoison whole stack frame now.
|
|
poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false);
|
|
} else {
|
|
poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false);
|
|
}
|
|
}
|
|
|
|
// We are done. Remove the old unused alloca instructions.
|
|
for (auto AI : AllocaVec) AI->eraseFromParent();
|
|
}
|
|
|
|
void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
|
|
IRBuilder<> &IRB, bool DoPoison) {
|
|
// For now just insert the call to ASan runtime.
|
|
Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy);
|
|
Value *SizeArg = ConstantInt::get(IntptrTy, Size);
|
|
IRB.CreateCall(
|
|
DoPoison ? AsanPoisonStackMemoryFunc : AsanUnpoisonStackMemoryFunc,
|
|
{AddrArg, SizeArg});
|
|
}
|
|
|
|
// Handling llvm.lifetime intrinsics for a given %alloca:
|
|
// (1) collect all llvm.lifetime.xxx(%size, %value) describing the alloca.
|
|
// (2) if %size is constant, poison memory for llvm.lifetime.end (to detect
|
|
// invalid accesses) and unpoison it for llvm.lifetime.start (the memory
|
|
// could be poisoned by previous llvm.lifetime.end instruction, as the
|
|
// variable may go in and out of scope several times, e.g. in loops).
|
|
// (3) if we poisoned at least one %alloca in a function,
|
|
// unpoison the whole stack frame at function exit.
|
|
|
|
AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
|
|
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
|
|
// We're intested only in allocas we can handle.
|
|
return ASan.isInterestingAlloca(*AI) ? AI : nullptr;
|
|
// See if we've already calculated (or started to calculate) alloca for a
|
|
// given value.
|
|
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
|
|
if (I != AllocaForValue.end()) return I->second;
|
|
// Store 0 while we're calculating alloca for value V to avoid
|
|
// infinite recursion if the value references itself.
|
|
AllocaForValue[V] = nullptr;
|
|
AllocaInst *Res = nullptr;
|
|
if (CastInst *CI = dyn_cast<CastInst>(V))
|
|
Res = findAllocaForValue(CI->getOperand(0));
|
|
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
|
|
for (Value *IncValue : PN->incoming_values()) {
|
|
// Allow self-referencing phi-nodes.
|
|
if (IncValue == PN) continue;
|
|
AllocaInst *IncValueAI = findAllocaForValue(IncValue);
|
|
// AI for incoming values should exist and should all be equal.
|
|
if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
|
|
return nullptr;
|
|
Res = IncValueAI;
|
|
}
|
|
}
|
|
if (Res) AllocaForValue[V] = Res;
|
|
return Res;
|
|
}
|
|
|
|
void FunctionStackPoisoner::handleDynamicAllocaCall(AllocaInst *AI) {
|
|
IRBuilder<> IRB(AI);
|
|
|
|
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);
|
|
|
|
// 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.
|
|
const unsigned ElementSize =
|
|
F.getParent()->getDataLayout().getTypeAllocSize(AI->getAllocatedType());
|
|
Value *OldSize =
|
|
IRB.CreateMul(IRB.CreateIntCast(AI->getArraySize(), IntptrTy, false),
|
|
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));
|
|
|
|
// Insert __asan_alloca_poison call for new created alloca.
|
|
IRB.CreateCall(AsanAllocaPoisonFunc, {NewAddress, OldSize});
|
|
|
|
// Store the last alloca's address to DynamicAllocaLayout. We'll need this
|
|
// for unpoisoning stuff.
|
|
IRB.CreateStore(IRB.CreatePtrToInt(NewAlloca, IntptrTy), DynamicAllocaLayout);
|
|
|
|
Value *NewAddressPtr = IRB.CreateIntToPtr(NewAddress, AI->getType());
|
|
|
|
// Replace all uses of AddessReturnedByAlloca with NewAddressPtr.
|
|
AI->replaceAllUsesWith(NewAddressPtr);
|
|
|
|
// We are done. Erase old alloca from parent.
|
|
AI->eraseFromParent();
|
|
}
|
|
|
|
// isSafeAccess returns true if Addr is always inbounds with respect to its
|
|
// base object. For example, it is a field access or an array access with
|
|
// constant inbounds index.
|
|
bool AddressSanitizer::isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis,
|
|
Value *Addr, uint64_t TypeSize) const {
|
|
SizeOffsetType SizeOffset = ObjSizeVis.compute(Addr);
|
|
if (!ObjSizeVis.bothKnown(SizeOffset)) return false;
|
|
uint64_t Size = SizeOffset.first.getZExtValue();
|
|
int64_t Offset = SizeOffset.second.getSExtValue();
|
|
// Three checks are required to ensure safety:
|
|
// . Offset >= 0 (since the offset is given from the base ptr)
|
|
// . Size >= Offset (unsigned)
|
|
// . Size - Offset >= NeededSize (unsigned)
|
|
return Offset >= 0 && Size >= uint64_t(Offset) &&
|
|
Size - uint64_t(Offset) >= TypeSize / 8;
|
|
}
|