//
//===----------------------------------------------------------------------===//
//
-// This file defines a check that marks a raw pointer to a C++ standard library
-// container's inner buffer released when the object is destroyed. This
-// information can be used by MallocChecker to detect use-after-free problems.
+// This file defines a check that marks a raw pointer to a C++ container's
+// inner buffer released when the object is destroyed. This information can
+// be used by MallocChecker to detect use-after-free problems.
//
//===----------------------------------------------------------------------===//
+#include "AllocationState.h"
#include "ClangSACheckers.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/BugReporter/CommonBugCategories.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
-#include "AllocationState.h"
using namespace clang;
using namespace ento;
+// FIXME: c_str() may be called on a string object many times, so it should
+// have a list of symbols associated with it.
+REGISTER_MAP_WITH_PROGRAMSTATE(RawPtrMap, const MemRegion *, SymbolRef)
+
namespace {
-class DanglingInternalBufferChecker : public Checker<check::DeadSymbols,
- check::PostCall> {
+class DanglingInternalBufferChecker
+ : public Checker<check::DeadSymbols, check::PostCall> {
CallDescription CStrFn;
public:
+ class DanglingBufferBRVisitor : public BugReporterVisitor {
+ SymbolRef PtrToBuf;
+
+ public:
+ DanglingBufferBRVisitor(SymbolRef Sym) : PtrToBuf(Sym) {}
+
+ static void *getTag() {
+ static int Tag = 0;
+ return &Tag;
+ }
+
+ void Profile(llvm::FoldingSetNodeID &ID) const override {
+ ID.AddPointer(getTag());
+ }
+
+ std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N,
+ const ExplodedNode *PrevN,
+ BugReporterContext &BRC,
+ BugReport &BR) override;
+
+ // FIXME: Scan the map once in the visitor's constructor and do a direct
+ // lookup by region.
+ bool isSymbolTracked(ProgramStateRef State, SymbolRef Sym) {
+ RawPtrMapTy Map = State->get<RawPtrMap>();
+ for (const auto Entry : Map) {
+ if (Entry.second == Sym)
+ return true;
+ }
+ return false;
+ }
+ };
+
DanglingInternalBufferChecker() : CStrFn("c_str") {}
/// Record the connection between the symbol returned by c_str() and the
} // end anonymous namespace
-// FIXME: c_str() may be called on a string object many times, so it should
-// have a list of symbols associated with it.
-REGISTER_MAP_WITH_PROGRAMSTATE(RawPtrMap, const MemRegion *, SymbolRef)
-
void DanglingInternalBufferChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
const auto *ICall = dyn_cast<CXXInstanceCall>(&Call);
C.addTransition(State);
}
+std::shared_ptr<PathDiagnosticPiece>
+DanglingInternalBufferChecker::DanglingBufferBRVisitor::VisitNode(
+ const ExplodedNode *N, const ExplodedNode *PrevN, BugReporterContext &BRC,
+ BugReport &BR) {
+
+ if (!isSymbolTracked(N->getState(), PtrToBuf) ||
+ isSymbolTracked(PrevN->getState(), PtrToBuf))
+ return nullptr;
+
+ const Stmt *S = PathDiagnosticLocation::getStmt(N);
+ if (!S)
+ return nullptr;
+
+ SmallString<256> Buf;
+ llvm::raw_svector_ostream OS(Buf);
+ OS << "Pointer to dangling buffer was obtained here";
+ PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
+ N->getLocationContext());
+ return std::make_shared<PathDiagnosticEventPiece>(Pos, OS.str(), true,
+ nullptr);
+}
+
+namespace clang {
+namespace ento {
+namespace allocation_state {
+
+std::unique_ptr<BugReporterVisitor> getDanglingBufferBRVisitor(SymbolRef Sym) {
+ return llvm::make_unique<
+ DanglingInternalBufferChecker::DanglingBufferBRVisitor>(Sym);
+}
+
+} // end namespace allocation_state
+} // end namespace ento
+} // end namespace clang
+
void ento::registerDanglingInternalBufferChecker(CheckerManager &Mgr) {
registerNewDeleteChecker(Mgr);
Mgr.registerChecker<DanglingInternalBufferChecker>();
class basic_string {
public:
~basic_string();
- const CharT *c_str();
+ const CharT *c_str() const;
};
typedef basic_string<char> string;
const char *c;
{
std::string s;
- c = s.c_str();
+ c = s.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
+ } // expected-note {{Internal buffer is released because the object was destroyed}}
+ consume(c); // expected-warning {{Use of memory after it is freed}}
+ // expected-note@-1 {{Use of memory after it is freed}}
+}
+
+void deref_after_scope_char2() {
+ const char *c;
+ {
+ std::string s;
+ c = s.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
} // expected-note {{Internal buffer is released because the object was destroyed}}
+ std::string s;
+ const char *c2 = s.c_str();
consume(c); // expected-warning {{Use of memory after it is freed}}
// expected-note@-1 {{Use of memory after it is freed}}
}
const wchar_t *w;
{
std::wstring ws;
- w = ws.c_str();
+ w = ws.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
} // expected-note {{Internal buffer is released because the object was destroyed}}
consume(w); // expected-warning {{Use of memory after it is freed}}
// expected-note@-1 {{Use of memory after it is freed}}
const char16_t *c16;
{
std::u16string s16;
- c16 = s16.c_str();
+ c16 = s16.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
} // expected-note {{Internal buffer is released because the object was destroyed}}
consume(c16); // expected-warning {{Use of memory after it is freed}}
// expected-note@-1 {{Use of memory after it is freed}}
const char32_t *c32;
{
std::u32string s32;
- c32 = s32.c_str();
+ c32 = s32.c_str(); // expected-note {{Pointer to dangling buffer was obtained here}}
} // expected-note {{Internal buffer is released because the object was destroyed}}
consume(c32); // expected-warning {{Use of memory after it is freed}}
// expected-note@-1 {{Use of memory after it is freed}}