1 files changed, 71 insertions, 0 deletions
diff --git a/lib/Checker/CheckSizeofPointer.cpp b/lib/Checker/CheckSizeofPointer.cpp
new file mode 100644
index 0000000..bbe494c
--- /dev/null
+++ b/lib/Checker/CheckSizeofPointer.cpp
@@ -0,0 +1,71 @@
+//==- CheckSizeofPointer.cpp - Check for sizeof on pointers ------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines a check for unintended use of sizeof() on pointer
+//  expressions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Checker/Checkers/LocalCheckers.h"
+
+using namespace clang;
+
+namespace {
+class WalkAST : public StmtVisitor<WalkAST> {
+  BugReporter &BR;
+
+public:
+  WalkAST(BugReporter &br) : BR(br) {}
+  void VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E);
+  void VisitStmt(Stmt *S) { VisitChildren(S); }
+  void VisitChildren(Stmt *S);
+};
+}
+
+void WalkAST::VisitChildren(Stmt *S) {
+  for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
+    if (Stmt *child = *I)
+      Visit(child);
+}
+
+// CWE-467: Use of sizeof() on a Pointer Type
+void WalkAST::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) {
+  if (!E->isSizeOf())
+    return;
+
+  // If an explicit type is used in the code, usually the coder knows what he is
+  // doing.
+  if (E->isArgumentType())
+    return;
+
+  QualType T = E->getTypeOfArgument();
+  if (T->isPointerType()) {
+
+    // Many false positives have the form 'sizeof *p'. This is reasonable 
+    // because people know what they are doing when they intentionally 
+    // dereference the pointer.
+    Expr *ArgEx = E->getArgumentExpr();
+    if (!isa<DeclRefExpr>(ArgEx->IgnoreParens()))
+      return;
+
+    SourceRange R = ArgEx->getSourceRange();
+    BR.EmitBasicReport("Potential unintended use of sizeof() on pointer type",
+                       "Logic",
+                       "The code calls sizeof() on a pointer type. "
+                       "This can produce an unexpected result.",
+                       E->getLocStart(), &R, 1);
+  }
+}
+
+void clang::CheckSizeofPointer(const Decl *D, BugReporter &BR) {
+  WalkAST walker(BR);
+  walker.Visit(D->getBody());
+}