Add a checker for CWE-466: Return of Pointer Value Outside of Expected Range.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86252 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 101 insertions, 0 deletions

diff --git a/include/clang/Analysis/PathSensitive/Checker.h b/include/clang/Analysis/PathSensitive/Checker.h
index 2564a73089..a87d72b60e 100644
--- a/include/clang/Analysis/PathSensitive/Checker.h
+++ b/include/clang/Analysis/PathSensitive/Checker.h
@@ -64,6 +64,11 @@ public:
   ConstraintManager &getConstraintManager() {
       return Eng.getConstraintManager();
   }
+
+  StoreManager &getStoreManager() {
+    return Eng.getStoreManager();
+  }
+
   ExplodedNodeSet &getNodeSet() { return Dst; }
   GRStmtNodeBuilder &getNodeBuilder() { return B; }
   ExplodedNode *&getPredecessor() { return Pred; }
diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt
index 111f273df6..1871b54a0d 100644
--- a/lib/Analysis/CMakeLists.txt
+++ b/lib/Analysis/CMakeLists.txt
@@ -36,6 +36,7 @@ add_clang_library(clangAnalysis
   PathDiagnostic.cpp
   RangeConstraintManager.cpp
   RegionStore.cpp
+  ReturnPointerRangeChecker.cpp
   ReturnStackAddressChecker.cpp
   ReturnUndefChecker.cpp
   SVals.cpp
diff --git a/lib/Analysis/GRExprEngineInternalChecks.cpp b/lib/Analysis/GRExprEngineInternalChecks.cpp
index 4bb5d226d1..b18e58dea2 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.cpp
+++ b/lib/Analysis/GRExprEngineInternalChecks.cpp
@@ -405,6 +405,7 @@ void GRExprEngine::RegisterInternalChecks() {
   // object.
   RegisterReturnStackAddressChecker(*this);
   RegisterReturnUndefChecker(*this);
+  RegisterReturnPointerRangeChecker(*this);
   registerCheck(new AttrNonNullChecker());
   registerCheck(new UndefinedArgChecker());
   registerCheck(new UndefinedAssignmentChecker());
diff --git a/lib/Analysis/GRExprEngineInternalChecks.h b/lib/Analysis/GRExprEngineInternalChecks.h
index 622b5ab110..b4a00d2e13 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.h
+++ b/lib/Analysis/GRExprEngineInternalChecks.h
@@ -21,6 +21,7 @@ class GRExprEngine;
 
 void RegisterReturnStackAddressChecker(GRExprEngine &Eng);
 void RegisterReturnUndefChecker(GRExprEngine &Eng);
+void RegisterReturnPointerRangeChecker(GRExprEngine &Eng);
   
 } // end clang namespace
 #endif
diff --git a/lib/Analysis/ReturnPointerRangeChecker.cpp b/lib/Analysis/ReturnPointerRangeChecker.cpp
new file mode 100644
index 0000000000..4ca72716a8
--- /dev/null
+++ b/lib/Analysis/ReturnPointerRangeChecker.cpp
@@ -0,0 +1,86 @@
+//== ReturnPointerRangeChecker.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 ReturnPointerRangeChecker, which is a path-sensitive check
+// which looks for an out-of-bound pointer being returned to callers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Analysis/PathSensitive/GRExprEngine.h"
+#include "clang/Analysis/PathSensitive/BugReporter.h"
+#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
+
+using namespace clang;
+
+namespace {
+class VISIBILITY_HIDDEN ReturnPointerRangeChecker : 
+    public CheckerVisitor<ReturnPointerRangeChecker> {      
+  BuiltinBug *BT;
+public:
+    ReturnPointerRangeChecker() : BT(0) {}
+    static void *getTag();
+    void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *RS);
+};
+}
+
+void clang::RegisterReturnPointerRangeChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new ReturnPointerRangeChecker());
+}
+
+void *ReturnPointerRangeChecker::getTag() {
+  static int x = 0; return &x;
+}
+
+void ReturnPointerRangeChecker::PreVisitReturnStmt(CheckerContext &C,
+                                                   const ReturnStmt *RS) {
+  const GRState *state = C.getState();
+
+  const Expr *RetE = RS->getRetValue();
+  if (!RetE)
+    return;
+ 
+  SVal V = state->getSVal(RetE);
+  const MemRegion *R = V.getAsRegion();
+
+  const ElementRegion *ER = dyn_cast_or_null<ElementRegion>(R);
+  if (!ER)
+    return;  
+
+  DefinedOrUnknownSVal &Idx = cast<DefinedOrUnknownSVal>(ER->getIndex());
+
+  // Zero index is always in bound, this also passes ElementRegions created for
+  // pointer casts.
+  if (Idx.isZeroConstant())
+    return;
+
+  SVal NumVal = C.getStoreManager().getSizeInElements(state,
+                                                      ER->getSuperRegion());
+  DefinedOrUnknownSVal &NumElements = cast<DefinedOrUnknownSVal>(NumVal);
+
+  const GRState *StInBound = state->AssumeInBound(Idx, NumElements, true);
+  const GRState *StOutBound = state->AssumeInBound(Idx, NumElements, false);
+  if (StOutBound && !StInBound) {
+    ExplodedNode *N = C.GenerateNode(RS, StOutBound, true);
+
+    if (!N)
+      return;
+  
+    if (!BT)
+      BT = new BuiltinBug("Return of Pointer Value Outside of Expected Range");
+  
+    // Generate a report for this bug.
+    RangedBugReport *report = 
+      new RangedBugReport(*BT, BT->getDescription().c_str(), N);
+
+    report->addRange(RS->getSourceRange());
+  
+    C.EmitReport(report);
+  }
+}
diff --git a/test/Analysis/region-only-test.c b/test/Analysis/region-only-test.c
index 8908adb105..b1e70a9054 100644
--- a/test/Analysis/region-only-test.c
+++ b/test/Analysis/region-only-test.c
@@ -11,3 +11,10 @@ void foo(int* p) {
   if (p[0] == 1)
     (void)*x; // no-warning
 }
+
+int a[10];
+
+int *f0() {
+  int *p = a+10;
+  return p; // expected-warning{{Return of Pointer Value Outside of Expected Range}}
+}