1 files changed, 91 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/CastSizeChecker.cpp b/lib/StaticAnalyzer/Checkers/CastSizeChecker.cpp
new file mode 100644
index 0000000..518cf96
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/CastSizeChecker.cpp
@@ -0,0 +1,91 @@
+//=== CastSizeChecker.cpp ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// CastSizeChecker checks when casting a malloc'ed symbolic region to type T,
+// whether the size of the symbolic region is a multiple of the size of T.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/AST/CharUnits.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerVisitor.h"
+#include "InternalChecks.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class CastSizeChecker : public CheckerVisitor<CastSizeChecker> {
+  BuiltinBug *BT;
+public:
+  CastSizeChecker() : BT(0) {}
+  static void *getTag();
+  void PreVisitCastExpr(CheckerContext &C, const CastExpr *B);
+};
+}
+
+void *CastSizeChecker::getTag() {
+  static int x;
+  return &x;
+}
+
+void CastSizeChecker::PreVisitCastExpr(CheckerContext &C, const CastExpr *CE) {
+  const Expr *E = CE->getSubExpr();
+  ASTContext &Ctx = C.getASTContext();
+  QualType ToTy = Ctx.getCanonicalType(CE->getType());
+  const PointerType *ToPTy = dyn_cast<PointerType>(ToTy.getTypePtr());
+
+  if (!ToPTy)
+    return;
+
+  QualType ToPointeeTy = ToPTy->getPointeeType();
+
+  // Only perform the check if 'ToPointeeTy' is a complete type.
+  if (ToPointeeTy->isIncompleteType())
+    return;
+
+  const GRState *state = C.getState();
+  const MemRegion *R = state->getSVal(E).getAsRegion();
+  if (R == 0)
+    return;
+
+  const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R);
+  if (SR == 0)
+    return;
+
+  SValBuilder &svalBuilder = C.getSValBuilder();
+  SVal extent = SR->getExtent(svalBuilder);
+  const llvm::APSInt *extentInt = svalBuilder.getKnownValue(state, extent);
+  if (!extentInt)
+    return;
+
+  CharUnits regionSize = CharUnits::fromQuantity(extentInt->getSExtValue());
+  CharUnits typeSize = C.getASTContext().getTypeSizeInChars(ToPointeeTy);
+
+  // Ignore void, and a few other un-sizeable types.
+  if (typeSize.isZero())
+    return;
+
+  if (regionSize % typeSize != 0) {
+    if (ExplodedNode *errorNode = C.generateSink()) {
+      if (!BT)
+        BT = new BuiltinBug("Cast region with wrong size.",
+                            "Cast a region whose size is not a multiple of the"
+                            " destination type size.");
+      RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(),
+                                               errorNode);
+      R->addRange(CE->getSourceRange());
+      C.EmitReport(R);
+    }
+  }
+}
+
+
+void ento::RegisterCastSizeChecker(ExprEngine &Eng) {
+  Eng.registerCheck(new CastSizeChecker());
+}