FixedAddressChecker.cpp revision 785950e59424dca7ce0081bebf13c0acd2c4fff6 
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/Checker.h"
18#include "clang/StaticAnalyzer/Core/CheckerManager.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
21
22using namespace clang;
23using namespace ento;
24
25namespace {
26class FixedAddressChecker
27  : public Checker< check::PreStmt<BinaryOperator> > {
28  mutable OwningPtr<BuiltinBug> BT;
29
30public:
31  void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
32};
33}
34
35void FixedAddressChecker::checkPreStmt(const BinaryOperator *B,
36                                       CheckerContext &C) const {
37  // Using a fixed address is not portable because that address will probably
38  // not be valid in all environments or platforms.
39
40  if (B->getOpcode() != BO_Assign)
41    return;
42
43  QualType T = B->getType();
44  if (!T->isPointerType())
45    return;
46
47  ProgramStateRef state = C.getState();
48  SVal RV = state->getSVal(B->getRHS(), C.getLocationContext());
49
50  if (!RV.isConstant() || RV.isZeroConstant())
51    return;
52
53  if (ExplodedNode *N = C.addTransition()) {
54    if (!BT)
55      BT.reset(new BuiltinBug("Use fixed address",
56                          "Using a fixed address is not portable because that "
57                          "address will probably not be valid in all "
58                          "environments or platforms."));
59    BugReport *R = new BugReport(*BT, BT->getDescription(), N);
60    R->addRange(B->getRHS()->getSourceRange());
61    C.emitReport(R);
62  }
63}
64
65void ento::registerFixedAddressChecker(CheckerManager &mgr) {
66  mgr.registerChecker<FixedAddressChecker>();
67}
68