C++ ObjCMethodCall::getArgExpr方法代码示例

void NilArgChecker::warnIfNilArg(CheckerContext &C,
                                 const ObjCMethodCall &msg,
                                 unsigned int Arg,
                                 FoundationClass Class,
                                 bool CanBeSubscript) const {
  // Check if the argument is nil.
  ProgramStateRef State = C.getState();
  if (!State->isNull(msg.getArgSVal(Arg)).isConstrainedTrue())
      return;

  // NOTE: We cannot throw non-fatal errors from warnIfNilExpr,
  // because it's called multiple times from some callers, so it'd cause
  // an unwanted state split if two or more non-fatal errors are thrown
  // within the same checker callback. For now we don't want to, but
  // it'll need to be fixed if we ever want to.
  if (ExplodedNode *N = C.generateErrorNode()) {
    SmallString<128> sbuf;
    llvm::raw_svector_ostream os(sbuf);

    if (CanBeSubscript && msg.getMessageKind() == OCM_Subscript) {

      if (Class == FC_NSArray) {
        os << "Array element cannot be nil";
      } else if (Class == FC_NSDictionary) {
        if (Arg == 0) {
          os << "Value stored into '";
          os << GetReceiverInterfaceName(msg) << "' cannot be nil";
        } else {
          assert(Arg == 1);
          os << "'"<< GetReceiverInterfaceName(msg) << "' key cannot be nil";
        }
      } else
        llvm_unreachable("Missing foundation class for the subscript expr");

    } else {
      if (Class == FC_NSDictionary) {
        if (Arg == 0)
          os << "Value argument ";
        else {
          assert(Arg == 1);
          os << "Key argument ";
        }
        os << "to '";
        msg.getSelector().print(os);
        os << "' cannot be nil";
      } else {
        os << "Argument to '" << GetReceiverInterfaceName(msg) << "' method '";
        msg.getSelector().print(os);
        os << "' cannot be nil";
      }
    }

    generateBugReport(N, os.str(), msg.getArgSourceRange(Arg),
                      msg.getArgExpr(Arg), C);
  }
}

void NilArgChecker::WarnIfNilArg(CheckerContext &C,
                                 const ObjCMethodCall &msg,
                                 unsigned int Arg,
                                 FoundationClass Class,
                                 bool CanBeSubscript) const {
  // Check if the argument is nil.
  ProgramStateRef State = C.getState();
  if (!State->isNull(msg.getArgSVal(Arg)).isConstrainedTrue())
      return;
      
  if (!BT)
    BT.reset(new APIMisuse("nil argument"));

  if (ExplodedNode *N = C.generateSink()) {
    SmallString<128> sbuf;
    llvm::raw_svector_ostream os(sbuf);

    if (CanBeSubscript && msg.getMessageKind() == OCM_Subscript) {

      if (Class == FC_NSArray) {
        os << "Array element cannot be nil";
      } else if (Class == FC_NSDictionary) {
        if (Arg == 0) {
          os << "Value stored into '";
          os << GetReceiverInterfaceName(msg) << "' cannot be nil";
        } else {
          assert(Arg == 1);
          os << "'"<< GetReceiverInterfaceName(msg) << "' key cannot be nil";
        }
      } else
        llvm_unreachable("Missing foundation class for the subscript expr");

    } else {
      if (Class == FC_NSDictionary) {
        if (Arg == 0)
          os << "Value argument ";
        else {
          assert(Arg == 1);
          os << "Key argument ";
        }
        os << "to '" << msg.getSelector().getAsString() << "' cannot be nil";
      } else {
        os << "Argument to '" << GetReceiverInterfaceName(msg) << "' method '"
        << msg.getSelector().getAsString() << "' cannot be nil";
      }
    }

    BugReport *R = new BugReport(*BT, os.str(), N);
    R->addRange(msg.getArgSourceRange(Arg));
    bugreporter::trackNullOrUndefValue(N, msg.getArgExpr(Arg), *R);
    C.emitReport(R);
  }
}

/// Returns the released value if M is a call a setter that releases
/// and nils out its underlying instance variable.
SymbolRef
ObjCDeallocChecker::getValueReleasedByNillingOut(const ObjCMethodCall &M,
                                                 CheckerContext &C) const {
  SVal ReceiverVal = M.getReceiverSVal();
  if (!ReceiverVal.isValid())
    return nullptr;

  if (M.getNumArgs() == 0)
    return nullptr;

  if (!M.getArgExpr(0)->getType()->isObjCRetainableType())
    return nullptr;

  // Is the first argument nil?
  SVal Arg = M.getArgSVal(0);
  ProgramStateRef notNilState, nilState;
  std::tie(notNilState, nilState) =
      M.getState()->assume(Arg.castAs<DefinedOrUnknownSVal>());
  if (!(nilState && !notNilState))
    return nullptr;

  const ObjCPropertyDecl *Prop = M.getAccessedProperty();
  if (!Prop)
    return nullptr;

  ObjCIvarDecl *PropIvarDecl = Prop->getPropertyIvarDecl();
  if (!PropIvarDecl)
    return nullptr;

  ProgramStateRef State = C.getState();

  SVal LVal = State->getLValue(PropIvarDecl, ReceiverVal);
  Optional<Loc> LValLoc = LVal.getAs<Loc>();
  if (!LValLoc)
    return nullptr;

  SVal CurrentValInIvar = State->getSVal(LValLoc.getValue());
  return CurrentValInIvar.getAsSymbol();
}

void VariadicMethodTypeChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
                                                    CheckerContext &C) const {
  if (!BT) {
    BT.reset(new APIMisuse(this,
                           "Arguments passed to variadic method aren't all "
                           "Objective-C pointer types"));

    ASTContext &Ctx = C.getASTContext();
    arrayWithObjectsS = GetUnarySelector("arrayWithObjects", Ctx);
    dictionaryWithObjectsAndKeysS =
      GetUnarySelector("dictionaryWithObjectsAndKeys", Ctx);
    setWithObjectsS = GetUnarySelector("setWithObjects", Ctx);
    orderedSetWithObjectsS = GetUnarySelector("orderedSetWithObjects", Ctx);

    initWithObjectsS = GetUnarySelector("initWithObjects", Ctx);
    initWithObjectsAndKeysS = GetUnarySelector("initWithObjectsAndKeys", Ctx);
  }

  if (!isVariadicMessage(msg))
      return;

  // We are not interested in the selector arguments since they have
  // well-defined types, so the compiler will issue a warning for them.
  unsigned variadicArgsBegin = msg.getSelector().getNumArgs();

  // We're not interested in the last argument since it has to be nil or the
  // compiler would have issued a warning for it elsewhere.
  unsigned variadicArgsEnd = msg.getNumArgs() - 1;

  if (variadicArgsEnd <= variadicArgsBegin)
    return;

  // Verify that all arguments have Objective-C types.
  Optional<ExplodedNode*> errorNode;

  for (unsigned I = variadicArgsBegin; I != variadicArgsEnd; ++I) {
    QualType ArgTy = msg.getArgExpr(I)->getType();
    if (ArgTy->isObjCObjectPointerType())
      continue;

    // Block pointers are treaded as Objective-C pointers.
    if (ArgTy->isBlockPointerType())
      continue;

    // Ignore pointer constants.
    if (msg.getArgSVal(I).getAs<loc::ConcreteInt>())
      continue;

    // Ignore pointer types annotated with 'NSObject' attribute.
    if (C.getASTContext().isObjCNSObjectType(ArgTy))
      continue;

    // Ignore CF references, which can be toll-free bridged.
    if (coreFoundation::isCFObjectRef(ArgTy))
      continue;

    // Generate only one error node to use for all bug reports.
    if (!errorNode.hasValue())
      errorNode = C.generateNonFatalErrorNode();

    if (!errorNode.getValue())
      continue;

    SmallString<128> sbuf;
    llvm::raw_svector_ostream os(sbuf);

    StringRef TypeName = GetReceiverInterfaceName(msg);
    if (!TypeName.empty())
      os << "Argument to '" << TypeName << "' method '";
    else
      os << "Argument to method '";

    msg.getSelector().print(os);
    os << "' should be an Objective-C pointer type, not '";
    ArgTy.print(os, C.getLangOpts());
    os << "'";

    auto R = llvm::make_unique<BugReport>(*BT, os.str(), errorNode.getValue());
    R->addRange(msg.getArgSourceRange(I));
    C.emitReport(std::move(R));
  }
}

//FIXME: Consider other methods than setObject like dictionaryWithObjectsAndKeys
/// Process call to NSMutableArray:setObject:forKey: 
void iOSAppSecInsecureKeyChainStorageChecker::checkPreObjCMessage 
  (const ObjCMethodCall &M, CheckerContext &C) const
{
  MSEC_DEBUG_FUNC("redwud:","ENTER") ;

  do
  {
    const ObjCInterfaceDecl *pRxInterface = M.getReceiverInterface() ;
    
    if ( !pRxInterface )
    {
      break ;
    }

    ASTContext &Ctx = C.getASTContext() ;
    Selector selCurr = M.getSelector() ; 

    initIdentifierInfo( Ctx ) ;

    //TODO: Check this with property, this might not work on it    
    //NSMutableDictionary 
    if ( pRxInterface ->getIdentifier() != m_piiNSMutableDictionary )
    {
      break ;
    } 

    //setObject 
    IdentifierInfo *piiSetObject = selCurr.getIdentifierInfoForSlot(0) ;  

    if ( piiSetObject != m_piiSetObject )
    {
       break ;
    }
    
    //forKey
    IdentifierInfo *piiForKey = selCurr.getIdentifierInfoForSlot(1) ;

    if ( piiForKey != m_piiForKey )
    {
       break ;
    }
    
    // MSEC_DEBUG("redwud: ", "'" << selCurr.getAsString() << "' num args: " << selCurr.getNumArgs() ) ;
    if ( selCurr.getNumArgs() != 2 )
    {
      // Unlikely to be of concerned 
      break ;
    }

    ProgramStateRef pProgState = C.getState() ;
    const LocationContext *pLCtx = C.getLocationContext() ; 

    //Get the value for "aKey" parameter (2nd)
    // Checking this first because checking the first parameter takes a bit longer    
    const Expr *pKeyExpr = M.getArgExpr(1) ;
    SVal argValKey = pProgState ->getSVal( pKeyExpr, pLCtx ) ;

    if ( !CMSecCommon::isSValContains( argValKey, "kSecAttrAccessible" ) )
    {
      // Not of concern
      break ; 
    }

    //Get the value for "anObject" parameter (1st)
    const Expr *pObjExpr = M.getArgExpr(0) ;
    SVal argValAnObject = pProgState ->getSVal( pObjExpr, pLCtx ) ;

    //Get receiver as symbol, should be used in either condition
    SymbolRef pSymQuery = M.getReceiverSVal().getAsSymbol() ;

    if ( !pSymQuery )
    {
      // redwud: Can't save empty receiver symbol,
      // so there is no point of moving on, 
      // there must be something wrong with this
      break ;
    }

    //Idea: if [query] is currently being tracked change it to different status, e.g. secure
    //      if not tracked add new secure state

    bool bInsecureObject = isInsecureObject( argValAnObject ) ; 

    pProgState = pProgState ->set <StreamMap>( pSymQuery, bInsecureObject ? 
      KeyChainState::getNotSecure() : KeyChainState::getSecure() ) ;   

    // Add transition of state
    //redwud: it seems that the states are transitioned at some point
    C.addTransition( pProgState ) ;

    MSEC_DEBUG( "redwud: ", "Finish checking!" ) ; 
  } while (_PASSING_) ;


  MSEC_DEBUG_FUNC("redwud:","EXIT") ;
}