1 files changed, 125 insertions, 0 deletions
diff --git a/lib/Checker/ReturnStackAddressChecker.cpp b/lib/Checker/ReturnStackAddressChecker.cpp
new file mode 100644
index 0000000..9cbabba
--- /dev/null
+++ b/lib/Checker/ReturnStackAddressChecker.cpp
@@ -0,0 +1,125 @@
+//== ReturnStackAddressChecker.cpp ------------------------------*- 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 ReturnStackAddressChecker, which is a path-sensitive
+// check which looks for the addresses of stack variables being returned to
+// callers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/GRExprEngine.h"
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/SmallString.h"
+
+using namespace clang;
+
+namespace {
+class ReturnStackAddressChecker : 
+    public CheckerVisitor<ReturnStackAddressChecker> {      
+  BuiltinBug *BT;
+public:
+  ReturnStackAddressChecker() : BT(0) {}
+  static void *getTag();
+  void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *RS);
+private:
+  void EmitStackError(CheckerContext &C, const MemRegion *R, const Expr *RetE);
+};
+}
+
+void clang::RegisterReturnStackAddressChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new ReturnStackAddressChecker());
+}
+
+void *ReturnStackAddressChecker::getTag() {
+  static int x = 0; return &x;
+}
+
+void ReturnStackAddressChecker::EmitStackError(CheckerContext &C,
+                                               const MemRegion *R,
+                                               const Expr *RetE) {
+	ExplodedNode *N = C.GenerateSink();
+
+	if (!N)
+		return;
+
+	if (!BT)
+		BT = new BuiltinBug("Return of address to stack-allocated memory");
+
+	// Generate a report for this bug.
+	llvm::SmallString<512> buf;
+	llvm::raw_svector_ostream os(buf);
+	SourceRange range;
+
+	// Get the base region, stripping away fields and elements.
+	R = R->getBaseRegion();
+
+	// Check if the region is a compound literal.
+	if (const CompoundLiteralRegion* CR = dyn_cast<CompoundLiteralRegion>(R)) {    
+		const CompoundLiteralExpr* CL = CR->getLiteralExpr();
+		os << "Address of stack memory associated with a compound literal "
+          "declared on line "
+       << C.getSourceManager().getInstantiationLineNumber(CL->getLocStart())
+       << " returned to caller";    
+		range = CL->getSourceRange();
+	}
+	else if (const AllocaRegion* AR = dyn_cast<AllocaRegion>(R)) {
+		const Expr* ARE = AR->getExpr();
+		SourceLocation L = ARE->getLocStart();
+		range = ARE->getSourceRange();    
+		os << "Address of stack memory allocated by call to alloca() on line "
+       << C.getSourceManager().getInstantiationLineNumber(L)
+       << " returned to caller";
+	}
+	else if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
+		const BlockDecl *BD = BR->getCodeRegion()->getDecl();
+		SourceLocation L = BD->getLocStart();
+		range = BD->getSourceRange();
+		os << "Address of stack-allocated block declared on line "
+       << C.getSourceManager().getInstantiationLineNumber(L)
+       << " returned to caller";
+	}
+	else if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
+		os << "Address of stack memory associated with local variable '"
+       << VR->getString() << "' returned";
+		range = VR->getDecl()->getSourceRange();
+	}
+	else {
+		assert(false && "Invalid region in ReturnStackAddressChecker.");
+		return;
+	}
+
+	RangedBugReport *report = new RangedBugReport(*BT, os.str(), N);
+	report->addRange(RetE->getSourceRange());
+	if (range.isValid())
+		report->addRange(range);
+
+	C.EmitReport(report);
+}	
+
+void ReturnStackAddressChecker::PreVisitReturnStmt(CheckerContext &C,
+                                                   const ReturnStmt *RS) {
+  
+  const Expr *RetE = RS->getRetValue();
+  if (!RetE)
+    return;
+ 
+  SVal V = C.getState()->getSVal(RetE);
+  const MemRegion *R = V.getAsRegion();
+
+  if (!R || !R->hasStackStorage())
+    return;  
+  
+  if (R->hasStackStorage()) {
+    EmitStackError(C, R, RetE);
+    return;
+  }
+}