first batch of changes

1 files changed, 654 insertions, 0 deletions

diff --git a/instrumentation/afl-llvm-pass.so.cc b/instrumentation/afl-llvm-pass.so.cc
new file mode 100644
index 00000000..8c8c987a
--- /dev/null
+++ b/instrumentation/afl-llvm-pass.so.cc
@@ -0,0 +1,654 @@
+/*
+   american fuzzy lop++ - LLVM-mode instrumentation pass
+   ---------------------------------------------------
+
+   Written by Laszlo Szekeres <lszekeres@google.com>,
+              Adrian Herrera <adrian.herrera@anu.edu.au>,
+              Michal Zalewski
+
+   LLVM integration design comes from Laszlo Szekeres. C bits copied-and-pasted
+   from afl-as.c are Michal's fault.
+
+   NGRAM previous location coverage comes from Adrian Herrera.
+
+   Copyright 2015, 2016 Google Inc. All rights reserved.
+   Copyright 2019-2020 AFLplusplus Project. All rights reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at:
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   This library is plugged into LLVM when invoking clang through afl-clang-fast.
+   It tells the compiler to add code roughly equivalent to the bits discussed
+   in ../afl-as.h.
+
+ */
+
+#define AFL_LLVM_PASS
+
+#include "config.h"
+#include "debug.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <list>
+#include <string>
+#include <fstream>
+#include <sys/time.h>
+
+#include "llvm/Config/llvm-config.h"
+#if LLVM_VERSION_MAJOR == 3 && LLVM_VERSION_MINOR < 5
+typedef long double max_align_t;
+#endif
+
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+
+#if LLVM_VERSION_MAJOR > 3 || \
+    (LLVM_VERSION_MAJOR == 3 && LLVM_VERSION_MINOR > 4)
+  #include "llvm/IR/DebugInfo.h"
+  #include "llvm/IR/CFG.h"
+#else
+  #include "llvm/DebugInfo.h"
+  #include "llvm/Support/CFG.h"
+#endif
+
+#include "afl-llvm-common.h"
+#include "llvm-ngram-coverage.h"
+
+using namespace llvm;
+
+namespace {
+
+class AFLCoverage : public ModulePass {
+
+ public:
+  static char ID;
+  AFLCoverage() : ModulePass(ID) {
+
+    initInstrumentList();
+
+  }
+
+  bool runOnModule(Module &M) override;
+
+ protected:
+  uint32_t ngram_size = 0;
+  uint32_t map_size = MAP_SIZE;
+  uint32_t function_minimum_size = 1;
+  char *   ctx_str = NULL, *skip_nozero = NULL;
+
+};
+
+}  // namespace
+
+char AFLCoverage::ID = 0;
+
+/* needed up to 3.9.0 */
+#if LLVM_VERSION_MAJOR == 3 && \
+    (LLVM_VERSION_MINOR < 9 || \
+     (LLVM_VERSION_MINOR == 9 && LLVM_VERSION_PATCH < 1))
+uint64_t PowerOf2Ceil(unsigned in) {
+
+  uint64_t in64 = in - 1;
+  in64 |= (in64 >> 1);
+  in64 |= (in64 >> 2);
+  in64 |= (in64 >> 4);
+  in64 |= (in64 >> 8);
+  in64 |= (in64 >> 16);
+  in64 |= (in64 >> 32);
+  return in64 + 1;
+
+}
+
+#endif
+
+/* #if LLVM_VERSION_STRING >= "4.0.1" */
+#if LLVM_VERSION_MAJOR > 4 || \
+    (LLVM_VERSION_MAJOR == 4 && LLVM_VERSION_PATCH >= 1)
+  #define AFL_HAVE_VECTOR_INTRINSICS 1
+#endif
+bool AFLCoverage::runOnModule(Module &M) {
+
+  LLVMContext &C = M.getContext();
+
+  IntegerType *Int8Ty = IntegerType::getInt8Ty(C);
+  IntegerType *Int32Ty = IntegerType::getInt32Ty(C);
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+  IntegerType *IntLocTy =
+      IntegerType::getIntNTy(C, sizeof(PREV_LOC_T) * CHAR_BIT);
+#endif
+  struct timeval  tv;
+  struct timezone tz;
+  u32             rand_seed;
+  unsigned int    cur_loc = 0;
+
+  /* Setup random() so we get Actually Random(TM) outputs from AFL_R() */
+  gettimeofday(&tv, &tz);
+  rand_seed = tv.tv_sec ^ tv.tv_usec ^ getpid();
+  AFL_SR(rand_seed);
+
+  /* Show a banner */
+
+  setvbuf(stdout, NULL, _IONBF, 0);
+
+  if (getenv("AFL_DEBUG")) debug = 1;
+
+  if ((isatty(2) && !getenv("AFL_QUIET")) || getenv("AFL_DEBUG") != NULL) {
+
+    SAYF(cCYA "afl-llvm-pass" VERSION cRST
+              " by <lszekeres@google.com> and <adrian.herrera@anu.edu.au>\n");
+
+  } else
+
+    be_quiet = 1;
+
+  /*
+    char *ptr;
+    if ((ptr = getenv("AFL_MAP_SIZE")) || (ptr = getenv("AFL_MAPSIZE"))) {
+
+      map_size = atoi(ptr);
+      if (map_size < 8 || map_size > (1 << 29))
+        FATAL("illegal AFL_MAP_SIZE %u, must be between 2^3 and 2^30",
+    map_size); if (map_size % 8) map_size = (((map_size >> 3) + 1) << 3);
+
+    }
+
+  */
+
+  /* Decide instrumentation ratio */
+
+  char *       inst_ratio_str = getenv("AFL_INST_RATIO");
+  unsigned int inst_ratio = 100;
+
+  if (inst_ratio_str) {
+
+    if (sscanf(inst_ratio_str, "%u", &inst_ratio) != 1 || !inst_ratio ||
+        inst_ratio > 100)
+      FATAL("Bad value of AFL_INST_RATIO (must be between 1 and 100)");
+
+  }
+
+#if LLVM_VERSION_MAJOR < 9
+  char *neverZero_counters_str = getenv("AFL_LLVM_NOT_ZERO");
+#endif
+  skip_nozero = getenv("AFL_LLVM_SKIP_NEVERZERO");
+
+  unsigned PrevLocSize = 0;
+
+  char *ngram_size_str = getenv("AFL_LLVM_NGRAM_SIZE");
+  if (!ngram_size_str) ngram_size_str = getenv("AFL_NGRAM_SIZE");
+  ctx_str = getenv("AFL_LLVM_CTX");
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+  /* Decide previous location vector size (must be a power of two) */
+  VectorType *PrevLocTy = NULL;
+
+  if (ngram_size_str)
+    if (sscanf(ngram_size_str, "%u", &ngram_size) != 1 || ngram_size < 2 ||
+        ngram_size > NGRAM_SIZE_MAX)
+      FATAL(
+          "Bad value of AFL_NGRAM_SIZE (must be between 2 and NGRAM_SIZE_MAX "
+          "(%u))",
+          NGRAM_SIZE_MAX);
+
+  if (ngram_size == 1) ngram_size = 0;
+  if (ngram_size)
+    PrevLocSize = ngram_size - 1;
+  else
+#else
+  if (ngram_size_str)
+  #ifndef LLVM_VERSION_PATCH
+    FATAL(
+        "Sorry, NGRAM branch coverage is not supported with llvm version "
+        "%d.%d.%d!",
+        LLVM_VERSION_MAJOR, LLVM_VERSION_MINOR, 0);
+  #else
+    FATAL(
+        "Sorry, NGRAM branch coverage is not supported with llvm version "
+        "%d.%d.%d!",
+        LLVM_VERSION_MAJOR, LLVM_VERSION_MINOR, LLVM_VERSION_PATCH);
+  #endif
+#endif
+    PrevLocSize = 1;
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+  int PrevLocVecSize = PowerOf2Ceil(PrevLocSize);
+  if (ngram_size)
+    PrevLocTy = VectorType::get(IntLocTy, PrevLocVecSize
+  #if LLVM_VERSION_MAJOR >= 12
+                                ,
+                                false
+  #endif
+    );
+#endif
+
+  /* Get globals for the SHM region and the previous location. Note that
+     __afl_prev_loc is thread-local. */
+
+  GlobalVariable *AFLMapPtr =
+      new GlobalVariable(M, PointerType::get(Int8Ty, 0), false,
+                         GlobalValue::ExternalLinkage, 0, "__afl_area_ptr");
+  GlobalVariable *AFLPrevLoc;
+  GlobalVariable *AFLContext = NULL;
+
+  if (ctx_str)
+#ifdef __ANDROID__
+    AFLContext = new GlobalVariable(
+        M, Int32Ty, false, GlobalValue::ExternalLinkage, 0, "__afl_prev_ctx");
+#else
+    AFLContext = new GlobalVariable(
+        M, Int32Ty, false, GlobalValue::ExternalLinkage, 0, "__afl_prev_ctx", 0,
+        GlobalVariable::GeneralDynamicTLSModel, 0, false);
+#endif
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+  if (ngram_size)
+  #ifdef __ANDROID__
+    AFLPrevLoc = new GlobalVariable(
+        M, PrevLocTy, /* isConstant */ false, GlobalValue::ExternalLinkage,
+        /* Initializer */ nullptr, "__afl_prev_loc");
+  #else
+    AFLPrevLoc = new GlobalVariable(
+        M, PrevLocTy, /* isConstant */ false, GlobalValue::ExternalLinkage,
+        /* Initializer */ nullptr, "__afl_prev_loc",
+        /* InsertBefore */ nullptr, GlobalVariable::GeneralDynamicTLSModel,
+        /* AddressSpace */ 0, /* IsExternallyInitialized */ false);
+  #endif
+  else
+#endif
+#ifdef __ANDROID__
+    AFLPrevLoc = new GlobalVariable(
+        M, Int32Ty, false, GlobalValue::ExternalLinkage, 0, "__afl_prev_loc");
+#else
+  AFLPrevLoc = new GlobalVariable(
+      M, Int32Ty, false, GlobalValue::ExternalLinkage, 0, "__afl_prev_loc", 0,
+      GlobalVariable::GeneralDynamicTLSModel, 0, false);
+#endif
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+  /* Create the vector shuffle mask for updating the previous block history.
+     Note that the first element of the vector will store cur_loc, so just set
+     it to undef to allow the optimizer to do its thing. */
+
+  SmallVector<Constant *, 32> PrevLocShuffle = {UndefValue::get(Int32Ty)};
+
+  for (unsigned I = 0; I < PrevLocSize - 1; ++I)
+    PrevLocShuffle.push_back(ConstantInt::get(Int32Ty, I));
+
+  for (int I = PrevLocSize; I < PrevLocVecSize; ++I)
+    PrevLocShuffle.push_back(ConstantInt::get(Int32Ty, PrevLocSize));
+
+  Constant *PrevLocShuffleMask = ConstantVector::get(PrevLocShuffle);
+#endif
+
+  // other constants we need
+  ConstantInt *Zero = ConstantInt::get(Int8Ty, 0);
+  ConstantInt *One = ConstantInt::get(Int8Ty, 1);
+
+  LoadInst *PrevCtx = NULL;  // CTX sensitive coverage
+
+  /* Instrument all the things! */
+
+  int inst_blocks = 0;
+  scanForDangerousFunctions(&M);
+
+  for (auto &F : M) {
+
+    int has_calls = 0;
+    if (debug)
+      fprintf(stderr, "FUNCTION: %s (%zu)\n", F.getName().str().c_str(),
+              F.size());
+
+    if (!isInInstrumentList(&F)) continue;
+
+    if (F.size() < function_minimum_size) continue;
+
+    for (auto &BB : F) {
+
+      BasicBlock::iterator IP = BB.getFirstInsertionPt();
+      IRBuilder<>          IRB(&(*IP));
+
+      // Context sensitive coverage
+      if (ctx_str && &BB == &F.getEntryBlock()) {
+
+        // load the context ID of the previous function and write to to a local
+        // variable on the stack
+        PrevCtx = IRB.CreateLoad(AFLContext);
+        PrevCtx->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+        // does the function have calls? and is any of the calls larger than one
+        // basic block?
+        for (auto &BB : F) {
+
+          if (has_calls) break;
+          for (auto &IN : BB) {
+
+            CallInst *callInst = nullptr;
+            if ((callInst = dyn_cast<CallInst>(&IN))) {
+
+              Function *Callee = callInst->getCalledFunction();
+              if (!Callee || Callee->size() < function_minimum_size)
+                continue;
+              else {
+
+                has_calls = 1;
+                break;
+
+              }
+
+            }
+
+          }
+
+        }
+
+        // if yes we store a context ID for this function in the global var
+        if (has_calls) {
+
+          ConstantInt *NewCtx = ConstantInt::get(Int32Ty, AFL_R(map_size));
+          StoreInst *  StoreCtx = IRB.CreateStore(NewCtx, AFLContext);
+          StoreCtx->setMetadata(M.getMDKindID("nosanitize"),
+                                MDNode::get(C, None));
+
+        }
+
+      }
+
+      if (AFL_R(100) >= inst_ratio) continue;
+
+      /* Make up cur_loc */
+
+      // cur_loc++;
+      cur_loc = AFL_R(map_size);
+
+/* There is a problem with Ubuntu 18.04 and llvm 6.0 (see issue #63).
+   The inline function successors() is not inlined and also not found at runtime
+   :-( As I am unable to detect Ubuntu18.04 heree, the next best thing is to
+   disable this optional optimization for LLVM 6.0.0 and Linux */
+#if !(LLVM_VERSION_MAJOR == 6 && LLVM_VERSION_MINOR == 0) || !defined __linux__
+      // only instrument if this basic block is the destination of a previous
+      // basic block that has multiple successors
+      // this gets rid of ~5-10% of instrumentations that are unnecessary
+      // result: a little more speed and less map pollution
+      int more_than_one = -1;
+      // fprintf(stderr, "BB %u: ", cur_loc);
+      for (pred_iterator PI = pred_begin(&BB), E = pred_end(&BB); PI != E;
+           ++PI) {
+
+        BasicBlock *Pred = *PI;
+
+        int count = 0;
+        if (more_than_one == -1) more_than_one = 0;
+        // fprintf(stderr, " %p=>", Pred);
+
+        for (succ_iterator SI = succ_begin(Pred), E = succ_end(Pred); SI != E;
+             ++SI) {
+
+          BasicBlock *Succ = *SI;
+
+          // if (count > 0)
+          //  fprintf(stderr, "|");
+          if (Succ != NULL) count++;
+          // fprintf(stderr, "%p", Succ);
+
+        }
+
+        if (count > 1) more_than_one = 1;
+
+      }
+
+      // fprintf(stderr, " == %d\n", more_than_one);
+      if (F.size() > 1 && more_than_one != 1) {
+
+        // in CTX mode we have to restore the original context for the caller -
+        // she might be calling other functions which need the correct CTX
+        if (ctx_str && has_calls) {
+
+          Instruction *Inst = BB.getTerminator();
+          if (isa<ReturnInst>(Inst) || isa<ResumeInst>(Inst)) {
+
+            IRBuilder<> Post_IRB(Inst);
+            StoreInst * RestoreCtx = Post_IRB.CreateStore(PrevCtx, AFLContext);
+            RestoreCtx->setMetadata(M.getMDKindID("nosanitize"),
+                                    MDNode::get(C, None));
+
+          }
+
+        }
+
+        continue;
+
+      }
+
+#endif
+
+      ConstantInt *CurLoc;
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+      if (ngram_size)
+        CurLoc = ConstantInt::get(IntLocTy, cur_loc);
+      else
+#endif
+        CurLoc = ConstantInt::get(Int32Ty, cur_loc);
+
+      /* Load prev_loc */
+
+      LoadInst *PrevLoc = IRB.CreateLoad(AFLPrevLoc);
+      PrevLoc->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+      Value *PrevLocTrans;
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+      /* "For efficiency, we propose to hash the tuple as a key into the
+         hit_count map as (prev_block_trans << 1) ^ curr_block_trans, where
+         prev_block_trans = (block_trans_1 ^ ... ^ block_trans_(n-1)" */
+
+      if (ngram_size)
+        PrevLocTrans =
+            IRB.CreateZExt(IRB.CreateXorReduce(PrevLoc), IRB.getInt32Ty());
+      else
+#endif
+        PrevLocTrans = PrevLoc;
+
+      if (ctx_str)
+        PrevLocTrans =
+            IRB.CreateZExt(IRB.CreateXor(PrevLocTrans, PrevCtx), Int32Ty);
+      else
+        PrevLocTrans = IRB.CreateZExt(PrevLocTrans, IRB.getInt32Ty());
+
+      /* Load SHM pointer */
+
+      LoadInst *MapPtr = IRB.CreateLoad(AFLMapPtr);
+      MapPtr->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+      Value *MapPtrIdx;
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+      if (ngram_size)
+        MapPtrIdx = IRB.CreateGEP(
+            MapPtr,
+            IRB.CreateZExt(
+                IRB.CreateXor(PrevLocTrans, IRB.CreateZExt(CurLoc, Int32Ty)),
+                Int32Ty));
+      else
+#endif
+        MapPtrIdx = IRB.CreateGEP(MapPtr, IRB.CreateXor(PrevLocTrans, CurLoc));
+
+      /* Update bitmap */
+
+      LoadInst *Counter = IRB.CreateLoad(MapPtrIdx);
+      Counter->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+      Value *Incr = IRB.CreateAdd(Counter, One);
+
+#if LLVM_VERSION_MAJOR < 9
+      if (neverZero_counters_str !=
+          NULL) {  // with llvm 9 we make this the default as the bug in llvm is
+                   // then fixed
+#else
+      if (!skip_nozero) {
+
+#endif
+        /* hexcoder: Realize a counter that skips zero during overflow.
+         * Once this counter reaches its maximum value, it next increments to 1
+         *
+         * Instead of
+         * Counter + 1 -> Counter
+         * we inject now this
+         * Counter + 1 -> {Counter, OverflowFlag}
+         * Counter + OverflowFlag -> Counter
+         */
+
+        auto cf = IRB.CreateICmpEQ(Incr, Zero);
+        auto carry = IRB.CreateZExt(cf, Int8Ty);
+        Incr = IRB.CreateAdd(Incr, carry);
+
+      }
+
+      IRB.CreateStore(Incr, MapPtrIdx)
+          ->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+      /* Update prev_loc history vector (by placing cur_loc at the head of the
+         vector and shuffle the other elements back by one) */
+
+      StoreInst *Store;
+
+#ifdef AFL_HAVE_VECTOR_INTRINSICS
+      if (ngram_size) {
+
+        Value *ShuffledPrevLoc = IRB.CreateShuffleVector(
+            PrevLoc, UndefValue::get(PrevLocTy), PrevLocShuffleMask);
+        Value *UpdatedPrevLoc = IRB.CreateInsertElement(
+            ShuffledPrevLoc, IRB.CreateLShr(CurLoc, (uint64_t)1), (uint64_t)0);
+
+        Store = IRB.CreateStore(UpdatedPrevLoc, AFLPrevLoc);
+        Store->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+      } else
+
+#endif
+      {
+
+        Store = IRB.CreateStore(ConstantInt::get(Int32Ty, cur_loc >> 1),
+                                AFLPrevLoc);
+
+      }
+
+      // in CTX mode we have to restore the original context for the caller -
+      // she might be calling other functions which need the correct CTX.
+      // Currently this is only needed for the Ubuntu clang-6.0 bug
+      if (ctx_str && has_calls) {
+
+        Instruction *Inst = BB.getTerminator();
+        if (isa<ReturnInst>(Inst) || isa<ResumeInst>(Inst)) {
+
+          IRBuilder<> Post_IRB(Inst);
+          StoreInst * RestoreCtx = Post_IRB.CreateStore(PrevCtx, AFLContext);
+          RestoreCtx->setMetadata(M.getMDKindID("nosanitize"),
+                                  MDNode::get(C, None));
+
+        }
+
+      }
+
+      inst_blocks++;
+
+    }
+
+  }
+
+  /*
+    // This is currently disabled because we not only need to create/insert a
+    // function (easy), but also add it as a constructor with an ID < 5
+
+    if (getenv("AFL_LLVM_DONTWRITEID") == NULL) {
+
+      // yes we could create our own function, insert it into ctors ...
+      // but this would be a pain in the butt ... so we use afl-llvm-rt.o
+
+      Function *f = ...
+
+      if (!f) {
+
+        fprintf(stderr,
+                "Error: init function could not be created (this should not
+    happen)\n"); exit(-1);
+
+      }
+
+      ... constructor for f = 4
+
+      BasicBlock *bb = &f->getEntryBlock();
+      if (!bb) {
+
+        fprintf(stderr,
+                "Error: init function does not have an EntryBlock (this should
+    not happen)\n"); exit(-1);
+
+      }
+
+      BasicBlock::iterator IP = bb->getFirstInsertionPt();
+      IRBuilder<>          IRB(&(*IP));
+
+      if (map_size <= 0x800000) {
+
+        GlobalVariable *AFLFinalLoc = new GlobalVariable(
+            M, Int32Ty, true, GlobalValue::ExternalLinkage, 0,
+            "__afl_final_loc");
+        ConstantInt *const_loc = ConstantInt::get(Int32Ty, map_size);
+        StoreInst *  StoreFinalLoc = IRB.CreateStore(const_loc, AFLFinalLoc);
+        StoreFinalLoc->setMetadata(M.getMDKindID("nosanitize"),
+                                     MDNode::get(C, None));
+
+      }
+
+    }
+
+  */
+
+  /* Say something nice. */
+
+  if (!be_quiet) {
+
+    if (!inst_blocks)
+      WARNF("No instrumentation targets found.");
+    else {
+
+      char modeline[100];
+      snprintf(modeline, sizeof(modeline), "%s%s%s%s%s",
+               getenv("AFL_HARDEN") ? "hardened" : "non-hardened",
+               getenv("AFL_USE_ASAN") ? ", ASAN" : "",
+               getenv("AFL_USE_MSAN") ? ", MSAN" : "",
+               getenv("AFL_USE_CFISAN") ? ", CFISAN" : "",
+               getenv("AFL_USE_UBSAN") ? ", UBSAN" : "");
+      OKF("Instrumented %u locations (%s mode, ratio %u%%).", inst_blocks,
+          modeline, inst_ratio);
+
+    }
+
+  }
+
+  return true;
+
+}
+
+static void registerAFLPass(const PassManagerBuilder &,
+                            legacy::PassManagerBase &PM) {
+
+  PM.add(new AFLCoverage());
+
+}
+
+static RegisterStandardPasses RegisterAFLPass(
+    PassManagerBuilder::EP_OptimizerLast, registerAFLPass);
+
+static RegisterStandardPasses RegisterAFLPass0(
+    PassManagerBuilder::EP_EnabledOnOptLevel0, registerAFLPass);
+