FixedAddressChecker.cpp revision 218893 
1//=== FixedAddressChecker.cpp - Fixed address usage checker ----*- C++ -*--===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This files defines FixedAddressChecker, a builtin checker that checks for
11// assignment of a fixed address to a pointer.
12// This check corresponds to CWE-587.
13//
14//===----------------------------------------------------------------------===//
15
16#include "ClangSACheckers.h"
17#include "clang/StaticAnalyzer/Core/CheckerManager.h"
18#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerVisitor.h"
20
21using namespace clang;
22using namespace ento;
23
24namespace {
25class FixedAddressChecker
26  : public CheckerVisitor<FixedAddressChecker> {
27  BuiltinBug *BT;
28public:
29  FixedAddressChecker() : BT(0) {}
30  static void *getTag();
31  void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
32};
33}
34
35void *FixedAddressChecker::getTag() {
36  static int x;
37  return &x;
38}
39
40void FixedAddressChecker::PreVisitBinaryOperator(CheckerContext &C,
41                                                 const BinaryOperator *B) {
42  // Using a fixed address is not portable because that address will probably
43  // not be valid in all environments or platforms.
44
45  if (B->getOpcode() != BO_Assign)
46    return;
47
48  QualType T = B->getType();
49  if (!T->isPointerType())
50    return;
51
52  const GRState *state = C.getState();
53
54  SVal RV = state->getSVal(B->getRHS());
55
56  if (!RV.isConstant() || RV.isZeroConstant())
57    return;
58
59  if (ExplodedNode *N = C.generateNode()) {
60    if (!BT)
61      BT = new BuiltinBug("Use fixed address",
62                          "Using a fixed address is not portable because that "
63                          "address will probably not be valid in all "
64                          "environments or platforms.");
65    RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(), N);
66    R->addRange(B->getRHS()->getSourceRange());
67    C.EmitReport(R);
68  }
69}
70
71static void RegisterFixedAddressChecker(ExprEngine &Eng) {
72  Eng.registerCheck(new FixedAddressChecker());
73}
74
75void ento::registerFixedAddressChecker(CheckerManager &mgr) {
76  mgr.addCheckerRegisterFunction(RegisterFixedAddressChecker);
77}
78