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 "ExprEngineInternalChecks.h" 17 #include "clang/StaticAnalyzer/BugReporter/BugType.h" 18 #include "clang/StaticAnalyzer/PathSensitive/CheckerVisitor.h" 19 20 using namespace clang; 21 using namespace ento; 22 23 namespace { 24 class FixedAddressChecker 25 : public CheckerVisitor<FixedAddressChecker> { 26 BuiltinBug *BT; 27 public: 28 FixedAddressChecker() : BT(0) {} 29 static void *getTag(); 30 void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B); 31 }; 32 } 33 34 void *FixedAddressChecker::getTag() { 35 static int x; 36 return &x; 37 } 38 39 void FixedAddressChecker::PreVisitBinaryOperator(CheckerContext &C, 40 const BinaryOperator *B) { 41 // Using a fixed address is not portable because that address will probably 42 // not be valid in all environments or platforms. 43 44 if (B->getOpcode() != BO_Assign) 45 return; 46 47 QualType T = B->getType(); 48 if (!T->isPointerType()) 49 return; 50 51 const GRState *state = C.getState(); 52 53 SVal RV = state->getSVal(B->getRHS()); 54 55 if (!RV.isConstant() || RV.isZeroConstant()) 56 return; 57 58 if (ExplodedNode *N = C.generateNode()) { 59 if (!BT) 60 BT = new BuiltinBug("Use fixed address", 61 "Using a fixed address is not portable because that " 62 "address will probably not be valid in all " 63 "environments or platforms."); 64 RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(), N); 65 R->addRange(B->getRHS()->getSourceRange()); 66 C.EmitReport(R); 67 } 68 } 69 70 void ento::RegisterFixedAddressChecker(ExprEngine &Eng) { 71 Eng.registerCheck(new FixedAddressChecker()); 72 } 73