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Diffstat (limited to 'contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp | 617 | 
1 files changed, 617 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp new file mode 100644 index 000000000000..20a46843e23e --- /dev/null +++ b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp @@ -0,0 +1,617 @@ +//===--- CallAndMessageChecker.cpp ------------------------------*- C++ -*--==// +// +//                     The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This defines CallAndMessageChecker, a builtin checker that checks for various +// errors of call and objc message expressions. +// +//===----------------------------------------------------------------------===// + +#include "ClangSACheckers.h" +#include "clang/AST/ParentMap.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" +#include "clang/StaticAnalyzer/Core/Checker.h" +#include "clang/StaticAnalyzer/Core/CheckerManager.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/Support/raw_ostream.h" + +using namespace clang; +using namespace ento; + +namespace { + +struct ChecksFilter { +  DefaultBool Check_CallAndMessageUnInitRefArg; +  DefaultBool Check_CallAndMessageChecker; + +  CheckName CheckName_CallAndMessageUnInitRefArg; +  CheckName CheckName_CallAndMessageChecker; +}; + +class CallAndMessageChecker +  : public Checker< check::PreStmt<CallExpr>, +                    check::PreStmt<CXXDeleteExpr>, +                    check::PreObjCMessage, +                    check::ObjCMessageNil, +                    check::PreCall > { +  mutable std::unique_ptr<BugType> BT_call_null; +  mutable std::unique_ptr<BugType> BT_call_undef; +  mutable std::unique_ptr<BugType> BT_cxx_call_null; +  mutable std::unique_ptr<BugType> BT_cxx_call_undef; +  mutable std::unique_ptr<BugType> BT_call_arg; +  mutable std::unique_ptr<BugType> BT_cxx_delete_undef; +  mutable std::unique_ptr<BugType> BT_msg_undef; +  mutable std::unique_ptr<BugType> BT_objc_prop_undef; +  mutable std::unique_ptr<BugType> BT_objc_subscript_undef; +  mutable std::unique_ptr<BugType> BT_msg_arg; +  mutable std::unique_ptr<BugType> BT_msg_ret; +  mutable std::unique_ptr<BugType> BT_call_few_args; + +public: +  ChecksFilter Filter; + +  void checkPreStmt(const CallExpr *CE, CheckerContext &C) const; +  void checkPreStmt(const CXXDeleteExpr *DE, CheckerContext &C) const; +  void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const; + +  /// Fill in the return value that results from messaging nil based on the +  /// return type and architecture and diagnose if the return value will be +  /// garbage. +  void checkObjCMessageNil(const ObjCMethodCall &msg, CheckerContext &C) const; + +  void checkPreCall(const CallEvent &Call, CheckerContext &C) const; + +private: +  bool PreVisitProcessArg(CheckerContext &C, SVal V, SourceRange ArgRange, +                          const Expr *ArgEx, int ArgumentNumber, +                          bool CheckUninitFields, const CallEvent &Call, +                          std::unique_ptr<BugType> &BT, +                          const ParmVarDecl *ParamDecl) const; + +  static void emitBadCall(BugType *BT, CheckerContext &C, const Expr *BadE); +  void emitNilReceiverBug(CheckerContext &C, const ObjCMethodCall &msg, +                          ExplodedNode *N) const; + +  void HandleNilReceiver(CheckerContext &C, +                         ProgramStateRef state, +                         const ObjCMethodCall &msg) const; + +  void LazyInit_BT(const char *desc, std::unique_ptr<BugType> &BT) const { +    if (!BT) +      BT.reset(new BuiltinBug(this, desc)); +  } +  bool uninitRefOrPointer(CheckerContext &C, const SVal &V, +                          SourceRange ArgRange, const Expr *ArgEx, +                          std::unique_ptr<BugType> &BT, +                          const ParmVarDecl *ParamDecl, const char *BD, +                          int ArgumentNumber) const; +}; +} // end anonymous namespace + +void CallAndMessageChecker::emitBadCall(BugType *BT, CheckerContext &C, +                                        const Expr *BadE) { +  ExplodedNode *N = C.generateErrorNode(); +  if (!N) +    return; + +  auto R = llvm::make_unique<BugReport>(*BT, BT->getName(), N); +  if (BadE) { +    R->addRange(BadE->getSourceRange()); +    if (BadE->isGLValue()) +      BadE = bugreporter::getDerefExpr(BadE); +    bugreporter::trackNullOrUndefValue(N, BadE, *R); +  } +  C.emitReport(std::move(R)); +} + +static void describeUninitializedArgumentInCall(const CallEvent &Call, +                                                int ArgumentNumber, +                                                llvm::raw_svector_ostream &Os) { +  switch (Call.getKind()) { +  case CE_ObjCMessage: { +    const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); +    switch (Msg.getMessageKind()) { +    case OCM_Message: +      Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) +         << " argument in message expression is an uninitialized value"; +      return; +    case OCM_PropertyAccess: +      assert(Msg.isSetter() && "Getters have no args"); +      Os << "Argument for property setter is an uninitialized value"; +      return; +    case OCM_Subscript: +      if (Msg.isSetter() && (ArgumentNumber == 0)) +        Os << "Argument for subscript setter is an uninitialized value"; +      else +        Os << "Subscript index is an uninitialized value"; +      return; +    } +    llvm_unreachable("Unknown message kind."); +  } +  case CE_Block: +    Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) +       << " block call argument is an uninitialized value"; +    return; +  default: +    Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) +       << " function call argument is an uninitialized value"; +    return; +  } +} + +bool CallAndMessageChecker::uninitRefOrPointer( +    CheckerContext &C, const SVal &V, SourceRange ArgRange, const Expr *ArgEx, +    std::unique_ptr<BugType> &BT, const ParmVarDecl *ParamDecl, const char *BD, +    int ArgumentNumber) const { +  if (!Filter.Check_CallAndMessageUnInitRefArg) +    return false; + +  // No parameter declaration available, i.e. variadic function argument. +  if(!ParamDecl) +    return false; + +  // If parameter is declared as pointer to const in function declaration, +  // then check if corresponding argument in function call is +  // pointing to undefined symbol value (uninitialized memory). +  SmallString<200> Buf; +  llvm::raw_svector_ostream Os(Buf); + +  if (ParamDecl->getType()->isPointerType()) { +    Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) +       << " function call argument is a pointer to uninitialized value"; +  } else if (ParamDecl->getType()->isReferenceType()) { +    Os << (ArgumentNumber + 1) << llvm::getOrdinalSuffix(ArgumentNumber + 1) +       << " function call argument is an uninitialized value"; +  } else +    return false; + +  if(!ParamDecl->getType()->getPointeeType().isConstQualified()) +    return false; + +  if (const MemRegion *SValMemRegion = V.getAsRegion()) { +    const ProgramStateRef State = C.getState(); +    const SVal PSV = State->getSVal(SValMemRegion, C.getASTContext().CharTy); +    if (PSV.isUndef()) { +      if (ExplodedNode *N = C.generateErrorNode()) { +        LazyInit_BT(BD, BT); +        auto R = llvm::make_unique<BugReport>(*BT, Os.str(), N); +        R->addRange(ArgRange); +        if (ArgEx) { +          bugreporter::trackNullOrUndefValue(N, ArgEx, *R); +        } +        C.emitReport(std::move(R)); +      } +      return true; +    } +  } +  return false; +} + +bool CallAndMessageChecker::PreVisitProcessArg(CheckerContext &C, +                                               SVal V, +                                               SourceRange ArgRange, +                                               const Expr *ArgEx, +                                               int ArgumentNumber, +                                               bool CheckUninitFields, +                                               const CallEvent &Call, +                                               std::unique_ptr<BugType> &BT, +                                               const ParmVarDecl *ParamDecl +                                               ) const { +  const char *BD = "Uninitialized argument value"; + +  if (uninitRefOrPointer(C, V, ArgRange, ArgEx, BT, ParamDecl, BD, +                         ArgumentNumber)) +    return true; + +  if (V.isUndef()) { +    if (ExplodedNode *N = C.generateErrorNode()) { +      LazyInit_BT(BD, BT); +      // Generate a report for this bug. +      SmallString<200> Buf; +      llvm::raw_svector_ostream Os(Buf); +      describeUninitializedArgumentInCall(Call, ArgumentNumber, Os); +      auto R = llvm::make_unique<BugReport>(*BT, Os.str(), N); + +      R->addRange(ArgRange); +      if (ArgEx) +        bugreporter::trackNullOrUndefValue(N, ArgEx, *R); +      C.emitReport(std::move(R)); +    } +    return true; +  } + +  if (!CheckUninitFields) +    return false; + +  if (Optional<nonloc::LazyCompoundVal> LV = +          V.getAs<nonloc::LazyCompoundVal>()) { + +    class FindUninitializedField { +    public: +      SmallVector<const FieldDecl *, 10> FieldChain; +    private: +      StoreManager &StoreMgr; +      MemRegionManager &MrMgr; +      Store store; +    public: +      FindUninitializedField(StoreManager &storeMgr, +                             MemRegionManager &mrMgr, Store s) +      : StoreMgr(storeMgr), MrMgr(mrMgr), store(s) {} + +      bool Find(const TypedValueRegion *R) { +        QualType T = R->getValueType(); +        if (const RecordType *RT = T->getAsStructureType()) { +          const RecordDecl *RD = RT->getDecl()->getDefinition(); +          assert(RD && "Referred record has no definition"); +          for (const auto *I : RD->fields()) { +            const FieldRegion *FR = MrMgr.getFieldRegion(I, R); +            FieldChain.push_back(I); +            T = I->getType(); +            if (T->getAsStructureType()) { +              if (Find(FR)) +                return true; +            } +            else { +              const SVal &V = StoreMgr.getBinding(store, loc::MemRegionVal(FR)); +              if (V.isUndef()) +                return true; +            } +            FieldChain.pop_back(); +          } +        } + +        return false; +      } +    }; + +    const LazyCompoundValData *D = LV->getCVData(); +    FindUninitializedField F(C.getState()->getStateManager().getStoreManager(), +                             C.getSValBuilder().getRegionManager(), +                             D->getStore()); + +    if (F.Find(D->getRegion())) { +      if (ExplodedNode *N = C.generateErrorNode()) { +        LazyInit_BT(BD, BT); +        SmallString<512> Str; +        llvm::raw_svector_ostream os(Str); +        os << "Passed-by-value struct argument contains uninitialized data"; + +        if (F.FieldChain.size() == 1) +          os << " (e.g., field: '" << *F.FieldChain[0] << "')"; +        else { +          os << " (e.g., via the field chain: '"; +          bool first = true; +          for (SmallVectorImpl<const FieldDecl *>::iterator +               DI = F.FieldChain.begin(), DE = F.FieldChain.end(); DI!=DE;++DI){ +            if (first) +              first = false; +            else +              os << '.'; +            os << **DI; +          } +          os << "')"; +        } + +        // Generate a report for this bug. +        auto R = llvm::make_unique<BugReport>(*BT, os.str(), N); +        R->addRange(ArgRange); + +        // FIXME: enhance track back for uninitialized value for arbitrary +        // memregions +        C.emitReport(std::move(R)); +      } +      return true; +    } +  } + +  return false; +} + +void CallAndMessageChecker::checkPreStmt(const CallExpr *CE, +                                         CheckerContext &C) const{ + +  const Expr *Callee = CE->getCallee()->IgnoreParens(); +  ProgramStateRef State = C.getState(); +  const LocationContext *LCtx = C.getLocationContext(); +  SVal L = State->getSVal(Callee, LCtx); + +  if (L.isUndef()) { +    if (!BT_call_undef) +      BT_call_undef.reset(new BuiltinBug( +          this, "Called function pointer is an uninitialized pointer value")); +    emitBadCall(BT_call_undef.get(), C, Callee); +    return; +  } + +  ProgramStateRef StNonNull, StNull; +  std::tie(StNonNull, StNull) = State->assume(L.castAs<DefinedOrUnknownSVal>()); + +  if (StNull && !StNonNull) { +    if (!BT_call_null) +      BT_call_null.reset(new BuiltinBug( +          this, "Called function pointer is null (null dereference)")); +    emitBadCall(BT_call_null.get(), C, Callee); +    return; +  } + +  C.addTransition(StNonNull); +} + +void CallAndMessageChecker::checkPreStmt(const CXXDeleteExpr *DE, +                                         CheckerContext &C) const { + +  SVal Arg = C.getSVal(DE->getArgument()); +  if (Arg.isUndef()) { +    StringRef Desc; +    ExplodedNode *N = C.generateErrorNode(); +    if (!N) +      return; +    if (!BT_cxx_delete_undef) +      BT_cxx_delete_undef.reset( +          new BuiltinBug(this, "Uninitialized argument value")); +    if (DE->isArrayFormAsWritten()) +      Desc = "Argument to 'delete[]' is uninitialized"; +    else +      Desc = "Argument to 'delete' is uninitialized"; +    BugType *BT = BT_cxx_delete_undef.get(); +    auto R = llvm::make_unique<BugReport>(*BT, Desc, N); +    bugreporter::trackNullOrUndefValue(N, DE, *R); +    C.emitReport(std::move(R)); +    return; +  } +} + +void CallAndMessageChecker::checkPreCall(const CallEvent &Call, +                                         CheckerContext &C) const { +  ProgramStateRef State = C.getState(); + +  // If this is a call to a C++ method, check if the callee is null or +  // undefined. +  if (const CXXInstanceCall *CC = dyn_cast<CXXInstanceCall>(&Call)) { +    SVal V = CC->getCXXThisVal(); +    if (V.isUndef()) { +      if (!BT_cxx_call_undef) +        BT_cxx_call_undef.reset( +            new BuiltinBug(this, "Called C++ object pointer is uninitialized")); +      emitBadCall(BT_cxx_call_undef.get(), C, CC->getCXXThisExpr()); +      return; +    } + +    ProgramStateRef StNonNull, StNull; +    std::tie(StNonNull, StNull) = +        State->assume(V.castAs<DefinedOrUnknownSVal>()); + +    if (StNull && !StNonNull) { +      if (!BT_cxx_call_null) +        BT_cxx_call_null.reset( +            new BuiltinBug(this, "Called C++ object pointer is null")); +      emitBadCall(BT_cxx_call_null.get(), C, CC->getCXXThisExpr()); +      return; +    } + +    State = StNonNull; +  } + +  const Decl *D = Call.getDecl(); +  if (D && (isa<FunctionDecl>(D) || isa<BlockDecl>(D))) { +    // If we have a function or block declaration, we can make sure we pass +    // enough parameters. +    unsigned Params = Call.parameters().size(); +    if (Call.getNumArgs() < Params) { +      ExplodedNode *N = C.generateErrorNode(); +      if (!N) +        return; + +      LazyInit_BT("Function call with too few arguments", BT_call_few_args); + +      SmallString<512> Str; +      llvm::raw_svector_ostream os(Str); +      if (isa<FunctionDecl>(D)) { +        os << "Function "; +      } else { +        assert(isa<BlockDecl>(D)); +        os << "Block "; +      } +      os << "taking " << Params << " argument" +         << (Params == 1 ? "" : "s") << " is called with fewer (" +         << Call.getNumArgs() << ")"; + +      C.emitReport( +          llvm::make_unique<BugReport>(*BT_call_few_args, os.str(), N)); +    } +  } + +  // Don't check for uninitialized field values in arguments if the +  // caller has a body that is available and we have the chance to inline it. +  // This is a hack, but is a reasonable compromise betweens sometimes warning +  // and sometimes not depending on if we decide to inline a function. +  const bool checkUninitFields = +    !(C.getAnalysisManager().shouldInlineCall() && (D && D->getBody())); + +  std::unique_ptr<BugType> *BT; +  if (isa<ObjCMethodCall>(Call)) +    BT = &BT_msg_arg; +  else +    BT = &BT_call_arg; + +  const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D); +  for (unsigned i = 0, e = Call.getNumArgs(); i != e; ++i) { +    const ParmVarDecl *ParamDecl = nullptr; +    if(FD && i < FD->getNumParams()) +      ParamDecl = FD->getParamDecl(i); +    if (PreVisitProcessArg(C, Call.getArgSVal(i), Call.getArgSourceRange(i), +                           Call.getArgExpr(i), i, +                           checkUninitFields, Call, *BT, ParamDecl)) +      return; +  } + +  // If we make it here, record our assumptions about the callee. +  C.addTransition(State); +} + +void CallAndMessageChecker::checkPreObjCMessage(const ObjCMethodCall &msg, +                                                CheckerContext &C) const { +  SVal recVal = msg.getReceiverSVal(); +  if (recVal.isUndef()) { +    if (ExplodedNode *N = C.generateErrorNode()) { +      BugType *BT = nullptr; +      switch (msg.getMessageKind()) { +      case OCM_Message: +        if (!BT_msg_undef) +          BT_msg_undef.reset(new BuiltinBug(this, +                                            "Receiver in message expression " +                                            "is an uninitialized value")); +        BT = BT_msg_undef.get(); +        break; +      case OCM_PropertyAccess: +        if (!BT_objc_prop_undef) +          BT_objc_prop_undef.reset(new BuiltinBug( +              this, "Property access on an uninitialized object pointer")); +        BT = BT_objc_prop_undef.get(); +        break; +      case OCM_Subscript: +        if (!BT_objc_subscript_undef) +          BT_objc_subscript_undef.reset(new BuiltinBug( +              this, "Subscript access on an uninitialized object pointer")); +        BT = BT_objc_subscript_undef.get(); +        break; +      } +      assert(BT && "Unknown message kind."); + +      auto R = llvm::make_unique<BugReport>(*BT, BT->getName(), N); +      const ObjCMessageExpr *ME = msg.getOriginExpr(); +      R->addRange(ME->getReceiverRange()); + +      // FIXME: getTrackNullOrUndefValueVisitor can't handle "super" yet. +      if (const Expr *ReceiverE = ME->getInstanceReceiver()) +        bugreporter::trackNullOrUndefValue(N, ReceiverE, *R); +      C.emitReport(std::move(R)); +    } +    return; +  } +} + +void CallAndMessageChecker::checkObjCMessageNil(const ObjCMethodCall &msg, +                                                CheckerContext &C) const { +  HandleNilReceiver(C, C.getState(), msg); +} + +void CallAndMessageChecker::emitNilReceiverBug(CheckerContext &C, +                                               const ObjCMethodCall &msg, +                                               ExplodedNode *N) const { + +  if (!BT_msg_ret) +    BT_msg_ret.reset( +        new BuiltinBug(this, "Receiver in message expression is 'nil'")); + +  const ObjCMessageExpr *ME = msg.getOriginExpr(); + +  QualType ResTy = msg.getResultType(); + +  SmallString<200> buf; +  llvm::raw_svector_ostream os(buf); +  os << "The receiver of message '"; +  ME->getSelector().print(os); +  os << "' is nil"; +  if (ResTy->isReferenceType()) { +    os << ", which results in forming a null reference"; +  } else { +    os << " and returns a value of type '"; +    msg.getResultType().print(os, C.getLangOpts()); +    os << "' that will be garbage"; +  } + +  auto report = llvm::make_unique<BugReport>(*BT_msg_ret, os.str(), N); +  report->addRange(ME->getReceiverRange()); +  // FIXME: This won't track "self" in messages to super. +  if (const Expr *receiver = ME->getInstanceReceiver()) { +    bugreporter::trackNullOrUndefValue(N, receiver, *report); +  } +  C.emitReport(std::move(report)); +} + +static bool supportsNilWithFloatRet(const llvm::Triple &triple) { +  return (triple.getVendor() == llvm::Triple::Apple && +          (triple.isiOS() || triple.isWatchOS() || +           !triple.isMacOSXVersionLT(10,5))); +} + +void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C, +                                              ProgramStateRef state, +                                              const ObjCMethodCall &Msg) const { +  ASTContext &Ctx = C.getASTContext(); +  static CheckerProgramPointTag Tag(this, "NilReceiver"); + +  // Check the return type of the message expression.  A message to nil will +  // return different values depending on the return type and the architecture. +  QualType RetTy = Msg.getResultType(); +  CanQualType CanRetTy = Ctx.getCanonicalType(RetTy); +  const LocationContext *LCtx = C.getLocationContext(); + +  if (CanRetTy->isStructureOrClassType()) { +    // Structure returns are safe since the compiler zeroes them out. +    SVal V = C.getSValBuilder().makeZeroVal(RetTy); +    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag); +    return; +  } + +  // Other cases: check if sizeof(return type) > sizeof(void*) +  if (CanRetTy != Ctx.VoidTy && C.getLocationContext()->getParentMap() +                                  .isConsumedExpr(Msg.getOriginExpr())) { +    // Compute: sizeof(void *) and sizeof(return type) +    const uint64_t voidPtrSize = Ctx.getTypeSize(Ctx.VoidPtrTy); +    const uint64_t returnTypeSize = Ctx.getTypeSize(CanRetTy); + +    if (CanRetTy.getTypePtr()->isReferenceType()|| +        (voidPtrSize < returnTypeSize && +         !(supportsNilWithFloatRet(Ctx.getTargetInfo().getTriple()) && +           (Ctx.FloatTy == CanRetTy || +            Ctx.DoubleTy == CanRetTy || +            Ctx.LongDoubleTy == CanRetTy || +            Ctx.LongLongTy == CanRetTy || +            Ctx.UnsignedLongLongTy == CanRetTy)))) { +      if (ExplodedNode *N = C.generateErrorNode(state, &Tag)) +        emitNilReceiverBug(C, Msg, N); +      return; +    } + +    // Handle the safe cases where the return value is 0 if the +    // receiver is nil. +    // +    // FIXME: For now take the conservative approach that we only +    // return null values if we *know* that the receiver is nil. +    // This is because we can have surprises like: +    // +    //   ... = [[NSScreens screens] objectAtIndex:0]; +    // +    // What can happen is that [... screens] could return nil, but +    // it most likely isn't nil.  We should assume the semantics +    // of this case unless we have *a lot* more knowledge. +    // +    SVal V = C.getSValBuilder().makeZeroVal(RetTy); +    C.addTransition(state->BindExpr(Msg.getOriginExpr(), LCtx, V), &Tag); +    return; +  } + +  C.addTransition(state); +} + +#define REGISTER_CHECKER(name)                                                 \ +  void ento::register##name(CheckerManager &mgr) {                             \ +    CallAndMessageChecker *Checker =                                           \ +        mgr.registerChecker<CallAndMessageChecker>();                          \ +    Checker->Filter.Check_##name = true;                                       \ +    Checker->Filter.CheckName_##name = mgr.getCurrentCheckName();              \ +  } + +REGISTER_CHECKER(CallAndMessageUnInitRefArg) +REGISTER_CHECKER(CallAndMessageChecker)  | 
