Add checker for CWE-587: Assignment of a Fixed Address to a Pointer.

llvm-svn: 86523

clang/include/clang/Analysis/PathSensitive/SVals.h

@@ -96,6 +96,8 @@ public:
     return getRawKind() > UnknownKind;
   }
 
+  bool isConstant() const;
+
   bool isZeroConstant() const;
 
   /// hasConjuredSymbol - If this SVal wraps a conjured symbol, return true;

clang/lib/Analysis/FixedAddressChecker.cpp

@@ -0,0 +1,69 @@
+//=== FixedAddressChecker.cpp - Fixed address usage checker ----*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This files defines FixedAddressChecker, a builtin checker that checks for
+// assignment of a fixed address to a pointer.
+// This check corresponds to CWE-587.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
+#include "GRExprEngineInternalChecks.h"
+
+using namespace clang;
+
+namespace {
+class VISIBILITY_HIDDEN FixedAddressChecker 
+  : public CheckerVisitor<FixedAddressChecker> {
+  BuiltinBug *BT;
+public:
+  FixedAddressChecker() : BT(0) {}
+  static void *getTag();
+  void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
+};
+}
+
+void *FixedAddressChecker::getTag() {
+  static int x;
+  return &x;
+}
+
+void FixedAddressChecker::PreVisitBinaryOperator(CheckerContext &C,
+                                                 const BinaryOperator *B) {
+  // Using a fixed address is not portable because that address will probably
+  // not be valid in all environments or platforms.
+
+  if (B->getOpcode() != BinaryOperator::Assign)
+    return;
+
+  QualType T = B->getType();
+  if (!T->isPointerType())
+    return;
+
+  const GRState *state = C.getState();
+
+  SVal RV = state->getSVal(B->getRHS());
+
+  if (!RV.isConstant() || RV.isZeroConstant())
+    return;
+
+  if (ExplodedNode *N = C.GenerateNode(B)) {
+    if (!BT)
+      BT = new BuiltinBug("Use fixed address", 
+                          "Using a fixed address is not portable because that address will probably not be valid in all environments or platforms.");
+    RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription().c_str(),
+                                             N);
+    R->addRange(B->getRHS()->getSourceRange());
+    C.EmitReport(R);
+  }
+}
+
+void clang::RegisterFixedAddressChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new FixedAddressChecker());
+}

clang/lib/Analysis/GRExprEngineInternalChecks.cpp

@@ -413,7 +413,7 @@ void GRExprEngine::RegisterInternalChecks() {
   RegisterReturnStackAddressChecker(*this);
   RegisterReturnUndefChecker(*this);
   RegisterPointerSubChecker(*this);
-
+  RegisterFixedAddressChecker(*this);
   // Note that this must be registered after ReturnStackAddressChecker.
   RegisterReturnPointerRangeChecker(*this);
 }

clang/lib/Analysis/GRExprEngineInternalChecks.h

@@ -25,5 +25,6 @@ void RegisterReturnStackAddressChecker(GRExprEngine &Eng);
 void RegisterReturnUndefChecker(GRExprEngine &Eng);
 void RegisterVLASizeChecker(GRExprEngine &Eng);
 void RegisterPointerSubChecker(GRExprEngine &Eng);
+void RegisterFixedAddressChecker(GRExprEngine &Eng);
 } // end clang namespace
 #endif

clang/lib/Analysis/SVals.cpp

@@ -173,6 +173,10 @@ nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {
 // Useful predicates.
 //===----------------------------------------------------------------------===//
 
+bool SVal::isConstant() const {
+  return isa<nonloc::ConcreteInt>(this) || isa<loc::ConcreteInt>(this);
+}
+
 bool SVal::isZeroConstant() const {
   if (isa<loc::ConcreteInt>(*this))
     return cast<loc::ConcreteInt>(*this).getValue() == 0;

clang/test/Analysis/ptr-arith.c

@@ -36,3 +36,8 @@ void f3() {
   int x, y;
   int d = &y - &x; // expected-warning{{Subtraction of two pointers that do not point to the same memory chunk may cause incorrect result.}}
 }
+
+void f4() {
+  int *p;
+  p = (int*) 0x10000; // expected-warning{{Using a fixed address is not portable because that address will probably not be valid in all environments or platforms.}}
+}