1 //==- CheckSizeofPointer.cpp - Check for sizeof on pointers ------*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a check for unintended use of sizeof() on pointer
13 //===----------------------------------------------------------------------===//
15 #include "ClangSACheckers.h"
16 #include "clang/AST/StmtVisitor.h"
17 #include "clang/StaticAnalyzer/Core/Checker.h"
18 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
21 using namespace clang;
25 class WalkAST : public StmtVisitor<WalkAST> {
30 WalkAST(BugReporter &br, AnalysisContext* ac) : BR(br), AC(ac) {}
31 void VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E);
32 void VisitStmt(Stmt *S) { VisitChildren(S); }
33 void VisitChildren(Stmt *S);
37 void WalkAST::VisitChildren(Stmt *S) {
38 for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
43 // CWE-467: Use of sizeof() on a Pointer Type
44 void WalkAST::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E) {
45 if (E->getKind() != UETT_SizeOf)
48 // If an explicit type is used in the code, usually the coder knows what he is
50 if (E->isArgumentType())
53 QualType T = E->getTypeOfArgument();
54 if (T->isPointerType()) {
56 // Many false positives have the form 'sizeof *p'. This is reasonable
57 // because people know what they are doing when they intentionally
58 // dereference the pointer.
59 Expr *ArgEx = E->getArgumentExpr();
60 if (!isa<DeclRefExpr>(ArgEx->IgnoreParens()))
63 SourceRange R = ArgEx->getSourceRange();
64 PathDiagnosticLocation ELoc =
65 PathDiagnosticLocation::createBegin(E, BR.getSourceManager(), AC);
66 BR.EmitBasicReport("Potential unintended use of sizeof() on pointer type",
68 "The code calls sizeof() on a pointer type. "
69 "This can produce an unexpected result.",
74 //===----------------------------------------------------------------------===//
75 // SizeofPointerChecker
76 //===----------------------------------------------------------------------===//
79 class SizeofPointerChecker : public Checker<check::ASTCodeBody> {
81 void checkASTCodeBody(const Decl *D, AnalysisManager& mgr,
82 BugReporter &BR) const {
83 WalkAST walker(BR, mgr.getAnalysisContext(D));
84 walker.Visit(D->getBody());
89 void ento::registerSizeofPointerChecker(CheckerManager &mgr) {
90 mgr.registerChecker<SizeofPointerChecker>();