[analyzer] Make VLA checker taint aware.

Also, slightly modify the diagnostic message in ArrayBound and DivZero (still use 'taint', which might not mean much to the user, but plan on changing it later).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148626 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 49 insertions, 27 deletions

diff --git a/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp b/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
index 0308bf5c11..74d4f24348 100644
--- a/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -26,14 +26,52 @@ using namespace ento;
 
 namespace {
 class VLASizeChecker : public Checker< check::PreStmt<DeclStmt> > {
-  mutable llvm::OwningPtr<BugType> BT_zero;
-  mutable llvm::OwningPtr<BugType> BT_undef;
-  
+  mutable llvm::OwningPtr<BugType> BT;
+  enum VLASize_Kind { VLA_Garbage, VLA_Zero, VLA_Tainted };
+
+  void reportBug(VLASize_Kind Kind,
+                 const Expr *SizeE,
+                 const ProgramState *State,
+                 CheckerContext &C) const;
 public:
   void checkPreStmt(const DeclStmt *DS, CheckerContext &C) const;
 };
 } // end anonymous namespace
 
+void VLASizeChecker::reportBug(VLASize_Kind Kind,
+                               const Expr *SizeE,
+                               const ProgramState *State,
+                               CheckerContext &C) const {
+  // Generate an error node.
+  ExplodedNode *N = C.generateSink(State);
+  if (!N)
+    return;
+
+  if (!BT)
+    BT.reset(new BuiltinBug("Dangerous variable-length array (VLA) declaration"));
+
+  llvm::SmallString<256> buf;
+  llvm::raw_svector_ostream os(buf);
+  os << "Declared variable-length array (VLA) ";
+  switch (Kind) {
+  case VLA_Garbage:
+    os << "uses a garbage value as its size";
+    break;
+  case VLA_Zero:
+    os << "has zero size";
+    break;
+  case VLA_Tainted:
+    os << "has tainted size";
+    break;
+  }
+
+  BugReport *report = new BugReport(*BT, os.str(), N);
+  report->addRange(SizeE->getSourceRange());
+  report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, SizeE));
+  C.EmitReport(report);
+  return;
+}
+
 void VLASizeChecker::checkPreStmt(const DeclStmt *DS, CheckerContext &C) const {
   if (!DS->isSingleDecl())
     return;
@@ -53,20 +91,7 @@ void VLASizeChecker::checkPreStmt(const DeclStmt *DS, CheckerContext &C) const {
   SVal sizeV = state->getSVal(SE, C.getLocationContext());
 
   if (sizeV.isUndef()) {
-    // Generate an error node.
-    ExplodedNode *N = C.generateSink();
-    if (!N)
-      return;
-    
-    if (!BT_undef)
-      BT_undef.reset(new BuiltinBug("Declared variable-length array (VLA) "
-                                    "uses a garbage value as its size"));
-
-    BugReport *report =
-      new BugReport(*BT_undef, BT_undef->getName(), N);
-    report->addRange(SE->getSourceRange());
-    report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, SE));
-    C.EmitReport(report);
+    reportBug(VLA_Garbage, SE, state, C);
     return;
   }
 
@@ -75,6 +100,12 @@ void VLASizeChecker::checkPreStmt(const DeclStmt *DS, CheckerContext &C) const {
   if (sizeV.isUnknown())
     return;
   
+  // Check if the size is tainted.
+  if (state->isTainted(sizeV)) {
+    reportBug(VLA_Tainted, SE, 0, C);
+    return;
+  }
+
   // Check if the size is zero.
   DefinedSVal sizeD = cast<DefinedSVal>(sizeV);
 
@@ -82,16 +113,7 @@ void VLASizeChecker::checkPreStmt(const DeclStmt *DS, CheckerContext &C) const {
   llvm::tie(stateNotZero, stateZero) = state->assume(sizeD);
 
   if (stateZero && !stateNotZero) {
-    ExplodedNode *N = C.generateSink(stateZero);
-    if (!BT_zero)
-      BT_zero.reset(new BuiltinBug("Declared variable-length array (VLA) has "
-                                   "zero size"));
-
-    BugReport *report =
-      new BugReport(*BT_zero, BT_zero->getName(), N);
-    report->addRange(SE->getSourceRange());
-    report->addVisitor(bugreporter::getTrackNullOrUndefValueVisitor(N, SE));
-    C.EmitReport(report);
+    reportBug(VLA_Zero, SE, stateZero, C);
     return;
   }