Add checker for CWE-469: Use of Pointer Subtraction to Determine Size. This
checker does not build sink nodes. Because svaluator computes an unknown value
for the subtraction now.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86517 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/GRExprEngineInternalChecks.cpp b/lib/Analysis/GRExprEngineInternalChecks.cpp
index 41ad018..8977b19 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.cpp
+++ b/lib/Analysis/GRExprEngineInternalChecks.cpp
@@ -412,6 +412,7 @@
RegisterDivZeroChecker(*this);
RegisterReturnStackAddressChecker(*this);
RegisterReturnUndefChecker(*this);
+ RegisterPointerSubChecker(*this);
// Note that this must be registered after ReturnStackAddressChecker.
RegisterReturnPointerRangeChecker(*this);
diff --git a/lib/Analysis/GRExprEngineInternalChecks.h b/lib/Analysis/GRExprEngineInternalChecks.h
index 42753b9..6d080dc 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.h
+++ b/lib/Analysis/GRExprEngineInternalChecks.h
@@ -24,6 +24,6 @@
void RegisterReturnStackAddressChecker(GRExprEngine &Eng);
void RegisterReturnUndefChecker(GRExprEngine &Eng);
void RegisterVLASizeChecker(GRExprEngine &Eng);
-
+void RegisterPointerSubChecker(GRExprEngine &Eng);
} // end clang namespace
#endif
diff --git a/lib/Analysis/PointerSubChecker.cpp b/lib/Analysis/PointerSubChecker.cpp
new file mode 100644
index 0000000..ebe051e
--- /dev/null
+++ b/lib/Analysis/PointerSubChecker.cpp
@@ -0,0 +1,71 @@
+//=== PointerSubChecker.cpp - Pointer subtraction checker ------*- C++ -*--===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This files defines PointerSubChecker, a builtin checker that checks for
+// pointer subtractions on two pointers pointing to different memory chunks.
+// This check corresponds to CWE-469.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
+#include "GRExprEngineInternalChecks.h"
+
+using namespace clang;
+
+namespace {
+class VISIBILITY_HIDDEN PointerSubChecker
+ : public CheckerVisitor<PointerSubChecker> {
+ BuiltinBug *BT;
+public:
+ PointerSubChecker() : BT(0) {}
+ static void *getTag();
+ void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
+};
+}
+
+void *PointerSubChecker::getTag() {
+ static int x;
+ return &x;
+}
+
+void PointerSubChecker::PreVisitBinaryOperator(CheckerContext &C,
+ const BinaryOperator *B) {
+ // When doing pointer subtraction, if the two pointers do not point to the
+ // same memory chunk, emit a warning.
+ if (B->getOpcode() != BinaryOperator::Sub)
+ return;
+
+ const GRState *state = C.getState();
+ SVal LV = state->getSVal(B->getLHS());
+ SVal RV = state->getSVal(B->getRHS());
+
+ const MemRegion *LR = LV.getAsRegion();
+ const MemRegion *RR = RV.getAsRegion();
+
+ if (!(LR && RR) || (LR == RR))
+ return;
+
+ // We don't reason about SymbolicRegions for now.
+ if (isa<SymbolicRegion>(LR) || isa<SymbolicRegion>(RR))
+ return;
+
+ if (ExplodedNode *N = C.GenerateNode(B)) {
+ if (!BT)
+ BT = new BuiltinBug("Pointer subtraction",
+ "Subtraction of two pointers that do not point to the same memory chunk may cause incorrect result.");
+ RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription().c_str(),
+ N);
+ R->addRange(B->getSourceRange());
+ C.EmitReport(R);
+ }
+}
+
+void clang::RegisterPointerSubChecker(GRExprEngine &Eng) {
+ Eng.registerCheck(new PointerSubChecker());
+}
diff --git a/test/Analysis/ptr-arith.c b/test/Analysis/ptr-arith.c
index d08d7e9..fc404e2 100644
--- a/test/Analysis/ptr-arith.c
+++ b/test/Analysis/ptr-arith.c
@@ -31,3 +31,8 @@
port = 10 * port + (*p - '0');
return port;
}
+
+void f3() {
+ int x, y;
+ int d = &y - &x; // expected-warning{{Subtraction of two pointers that do not point to the same memory chunk may cause incorrect result.}}
+}