1 //===-- InvalidatedIteratorChecker.cpp ----------------------------*- C++ -*--//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Defines a checker for access of invalidated iterators.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
14 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
15 #include "clang/StaticAnalyzer/Core/Checker.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
18 
19 
20 #include "Iterator.h"
21 
22 using namespace clang;
23 using namespace ento;
24 using namespace iterator;
25 
26 namespace {
27 
28 class InvalidatedIteratorChecker
29   : public Checker<check::PreCall, check::PreStmt<UnaryOperator>,
30                    check::PreStmt<BinaryOperator>,
31                    check::PreStmt<ArraySubscriptExpr>,
32                    check::PreStmt<MemberExpr>> {
33 
34   std::unique_ptr<BugType> InvalidatedBugType;
35 
36   void verifyAccess(CheckerContext &C, const SVal &Val) const;
37   void reportBug(const StringRef &Message, const SVal &Val,
38                  CheckerContext &C, ExplodedNode *ErrNode) const;
39 public:
40   InvalidatedIteratorChecker();
41 
42   void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
43   void checkPreStmt(const UnaryOperator *UO, CheckerContext &C) const;
44   void checkPreStmt(const BinaryOperator *BO, CheckerContext &C) const;
45   void checkPreStmt(const ArraySubscriptExpr *ASE, CheckerContext &C) const;
46   void checkPreStmt(const MemberExpr *ME, CheckerContext &C) const;
47 
48 };
49 
50 } //namespace
51 
52 InvalidatedIteratorChecker::InvalidatedIteratorChecker() {
53   InvalidatedBugType.reset(
54       new BugType(this, "Iterator invalidated", "Misuse of STL APIs"));
55 }
56 
57 void InvalidatedIteratorChecker::checkPreCall(const CallEvent &Call,
58                                               CheckerContext &C) const {
59   // Check for access of invalidated position
60   const auto *Func = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
61   if (!Func)
62     return;
63 
64   if (Func->isOverloadedOperator() &&
65       isAccessOperator(Func->getOverloadedOperator())) {
66     // Check for any kind of access of invalidated iterator positions
67     if (const auto *InstCall = dyn_cast<CXXInstanceCall>(&Call)) {
68       verifyAccess(C, InstCall->getCXXThisVal());
69     } else {
70       verifyAccess(C, Call.getArgSVal(0));
71     }
72   }
73 }
74 
75 void InvalidatedIteratorChecker::checkPreStmt(const UnaryOperator *UO,
76                                               CheckerContext &C) const {
77   if (isa<CXXThisExpr>(UO->getSubExpr()))
78     return;
79 
80   ProgramStateRef State = C.getState();
81   UnaryOperatorKind OK = UO->getOpcode();
82   SVal SubVal = State->getSVal(UO->getSubExpr(), C.getLocationContext());
83 
84   if (isAccessOperator(OK)) {
85     verifyAccess(C, SubVal);
86   }
87 }
88 
89 void InvalidatedIteratorChecker::checkPreStmt(const BinaryOperator *BO,
90                                               CheckerContext &C) const {
91   ProgramStateRef State = C.getState();
92   BinaryOperatorKind OK = BO->getOpcode();
93   SVal LVal = State->getSVal(BO->getLHS(), C.getLocationContext());
94 
95   if (isAccessOperator(OK)) {
96     verifyAccess(C, LVal);
97   }
98 }
99 
100 void InvalidatedIteratorChecker::checkPreStmt(const ArraySubscriptExpr *ASE,
101                                               CheckerContext &C) const {
102   ProgramStateRef State = C.getState();
103   SVal LVal = State->getSVal(ASE->getLHS(), C.getLocationContext());
104   verifyAccess(C, LVal);
105 }
106 
107 void InvalidatedIteratorChecker::checkPreStmt(const MemberExpr *ME,
108                                               CheckerContext &C) const {
109   if (!ME->isArrow() || ME->isImplicitAccess())
110     return;
111 
112   ProgramStateRef State = C.getState();
113   SVal BaseVal = State->getSVal(ME->getBase(), C.getLocationContext());
114   verifyAccess(C, BaseVal);
115 }
116 
117 void InvalidatedIteratorChecker::verifyAccess(CheckerContext &C, const SVal &Val) const {
118   auto State = C.getState();
119   const auto *Pos = getIteratorPosition(State, Val);
120   if (Pos && !Pos->isValid()) {
121     auto *N = C.generateErrorNode(State);
122     if (!N) {
123       return;
124     }
125     reportBug("Invalidated iterator accessed.", Val, C, N);
126   }
127 }
128 
129 void InvalidatedIteratorChecker::reportBug(const StringRef &Message,
130                                            const SVal &Val, CheckerContext &C,
131                                            ExplodedNode *ErrNode) const {
132   auto R = std::make_unique<PathSensitiveBugReport>(*InvalidatedBugType,
133                                                     Message, ErrNode);
134   R->markInteresting(Val);
135   C.emitReport(std::move(R));
136 }
137 
138 void ento::registerInvalidatedIteratorChecker(CheckerManager &mgr) {
139   mgr.registerChecker<InvalidatedIteratorChecker>();
140 }
141 
142 bool ento::shouldRegisterInvalidatedIteratorChecker(const CheckerManager &mgr) {
143   return true;
144 }
145