[cfe-commits] r105602 - in /cfe/trunk: lib/Checker/CMakeLists.txt lib/Checker/GRExprEngineExperimentalChecks.cpp lib/Checker/GRExprEngineInternalChecks.h lib/Checker/StackAddrLeakChecker.cpp test/Analysis/stackaddrleak.c
Zhongxing Xu
xuzhongxing at gmail.com
Tue Jun 8 03:00:00 PDT 2010
Author: zhongxingxu
Date: Tue Jun 8 05:00:00 2010
New Revision: 105602
URL: http://llvm.org/viewvc/llvm-project?rev=105602&view=rev
Log:
Add a checker check if a global variable holds a local variable's address after
the function call is left where the local variable is declared.
Added:
cfe/trunk/lib/Checker/StackAddrLeakChecker.cpp
cfe/trunk/test/Analysis/stackaddrleak.c
Modified:
cfe/trunk/lib/Checker/CMakeLists.txt
cfe/trunk/lib/Checker/GRExprEngineExperimentalChecks.cpp
cfe/trunk/lib/Checker/GRExprEngineInternalChecks.h
Modified: cfe/trunk/lib/Checker/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Checker/CMakeLists.txt?rev=105602&r1=105601&r2=105602&view=diff
==============================================================================
--- cfe/trunk/lib/Checker/CMakeLists.txt (original)
+++ cfe/trunk/lib/Checker/CMakeLists.txt Tue Jun 8 05:00:00 2010
@@ -57,6 +57,7 @@
ReturnUndefChecker.cpp
SimpleConstraintManager.cpp
SimpleSValuator.cpp
+ StackAddrLeakChecker.cpp
Store.cpp
SVals.cpp
SValuator.cpp
Modified: cfe/trunk/lib/Checker/GRExprEngineExperimentalChecks.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Checker/GRExprEngineExperimentalChecks.cpp?rev=105602&r1=105601&r2=105602&view=diff
==============================================================================
--- cfe/trunk/lib/Checker/GRExprEngineExperimentalChecks.cpp (original)
+++ cfe/trunk/lib/Checker/GRExprEngineExperimentalChecks.cpp Tue Jun 8 05:00:00 2010
@@ -38,4 +38,5 @@
RegisterCastToStructChecker(Eng);
RegisterCastSizeChecker(Eng);
RegisterArrayBoundChecker(Eng);
+ RegisterStackAddrLeakChecker(Eng);
}
Modified: cfe/trunk/lib/Checker/GRExprEngineInternalChecks.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Checker/GRExprEngineInternalChecks.h?rev=105602&r1=105601&r2=105602&view=diff
==============================================================================
--- cfe/trunk/lib/Checker/GRExprEngineInternalChecks.h (original)
+++ cfe/trunk/lib/Checker/GRExprEngineInternalChecks.h Tue Jun 8 05:00:00 2010
@@ -36,6 +36,7 @@
void RegisterReturnPointerRangeChecker(GRExprEngine &Eng);
void RegisterReturnStackAddressChecker(GRExprEngine &Eng);
void RegisterReturnUndefChecker(GRExprEngine &Eng);
+void RegisterStackAddrLeakChecker(GRExprEngine &Eng);
void RegisterUndefBranchChecker(GRExprEngine &Eng);
void RegisterUndefCapturedBlockVarChecker(GRExprEngine &Eng);
void RegisterUndefResultChecker(GRExprEngine &Eng);
Added: cfe/trunk/lib/Checker/StackAddrLeakChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Checker/StackAddrLeakChecker.cpp?rev=105602&view=auto
==============================================================================
--- cfe/trunk/lib/Checker/StackAddrLeakChecker.cpp (added)
+++ cfe/trunk/lib/Checker/StackAddrLeakChecker.cpp Tue Jun 8 05:00:00 2010
@@ -0,0 +1,94 @@
+//=== StackAddrLeakChecker.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 stack address leak checker, which checks if an invalid
+// stack address is stored into a global or heap location. See CERT DCL30-C.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/BugReporter/BugType.h"
+#include "clang/Checker/PathSensitive/Checker.h"
+#include "clang/Checker/PathSensitive/GRState.h"
+
+using namespace clang;
+
+namespace {
+class StackAddrLeakChecker : public Checker {
+ BuiltinBug *BT_stackleak;
+
+public:
+ StackAddrLeakChecker() : BT_stackleak(0) {}
+ static void *getTag() {
+ static int x;
+ return &x;
+ }
+
+ void EvalEndPath(GREndPathNodeBuilder &B, void *tag, GRExprEngine &Eng);
+};
+}
+
+void clang::RegisterStackAddrLeakChecker(GRExprEngine &Eng) {
+ Eng.registerCheck(new StackAddrLeakChecker());
+}
+
+void StackAddrLeakChecker::EvalEndPath(GREndPathNodeBuilder &B, void *tag,
+ GRExprEngine &Eng) {
+ SaveAndRestore<bool> OldHasGen(B.HasGeneratedNode);
+ const GRState *state = B.getState();
+ TranslationUnitDecl *TU = Eng.getContext().getTranslationUnitDecl();
+
+ // Check each global variable if it contains a MemRegionVal of a stack
+ // variable declared in the function we are leaving.
+ for (DeclContext::decl_iterator I = TU->decls_begin(), E = TU->decls_end();
+ I != E; ++I) {
+ if (VarDecl *VD = dyn_cast<VarDecl>(*I)) {
+ const LocationContext *LCtx = B.getPredecessor()->getLocationContext();
+ SVal L = state->getLValue(VD, LCtx);
+ SVal V = state->getSVal(cast<Loc>(L));
+ if (loc::MemRegionVal *RV = dyn_cast<loc::MemRegionVal>(&V)) {
+ const MemRegion *R = RV->getRegion();
+ // Strip fields or elements to get the variable region.
+ R = R->getBaseRegion();
+ if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
+ const VarDecl *VD = VR->getDecl();
+ const DeclContext *DC = VD->getDeclContext();
+ // Get the function where the variable is declared.
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {
+ // Check if the function is the function we are leaving.
+ if (FD == LCtx->getDecl()) {
+ // The variable is declared in the function scope which we are
+ // leaving. Keeping this variable's address in a global variable
+ // is dangerous.
+ // FIXME: Currently VarRegion does not carry context information.
+ // So we cannot tell if the local variable instance is in the
+ // current stack frame. This may produce false positive in
+ // recursive function call context. But that's a rare case.
+
+ // FIXME: better warning location.
+
+ ExplodedNode *N = B.generateNode(state, tag, B.getPredecessor());
+ if (N) {
+ if (!BT_stackleak)
+ BT_stackleak = new BuiltinBug("Stack address leak",
+ "Stack address was saved into a global variable. "
+ "This is dangerous because the address will become invalid "
+ "after returning from the function.");
+ BugReport *R = new BugReport(*BT_stackleak,
+ BT_stackleak->getDescription(), N);
+ Eng.getBugReporter().EmitReport(R);
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
Added: cfe/trunk/test/Analysis/stackaddrleak.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/stackaddrleak.c?rev=105602&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/stackaddrleak.c (added)
+++ cfe/trunk/test/Analysis/stackaddrleak.c Tue Jun 8 05:00:00 2010
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -analyze -analyzer-check-objc-mem -analyzer-store region -analyzer-experimental-internal-checks -verify %s
+
+char const *p;
+
+void f0() {
+ char const str[] = "This will change";
+ p = str; // expected-warning {{Stack address was saved into a global variable.}}
+}
+
+void f1() {
+ char const str[] = "This will change";
+ p = str;
+ p = 0; // no-warning
+}
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