1 files changed, 419 insertions, 0 deletions
diff --git a/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
new file mode 100644
index 000000000000..1ea5e0769513
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
@@ -0,0 +1,419 @@
+//===-- StreamChecker.cpp -----------------------------------------*- C++ -*--//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines checkers that model and check stream handling functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+struct StreamState {
+  enum Kind { Opened, Closed, OpenFailed, Escaped } K;
+  const Stmt *S;
+
+  StreamState(Kind k, const Stmt *s) : K(k), S(s) {}
+
+  bool isOpened() const { return K == Opened; }
+  bool isClosed() const { return K == Closed; }
+  //bool isOpenFailed() const { return K == OpenFailed; }
+  //bool isEscaped() const { return K == Escaped; }
+
+  bool operator==(const StreamState &X) const {
+    return K == X.K && S == X.S;
+  }
+
+  static StreamState getOpened(const Stmt *s) { return StreamState(Opened, s); }
+  static StreamState getClosed(const Stmt *s) { return StreamState(Closed, s); }
+  static StreamState getOpenFailed(const Stmt *s) {
+    return StreamState(OpenFailed, s);
+  }
+  static StreamState getEscaped(const Stmt *s) {
+    return StreamState(Escaped, s);
+  }
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ID.AddInteger(K);
+    ID.AddPointer(S);
+  }
+};
+
+class StreamChecker : public Checker<eval::Call,
+                                     check::DeadSymbols > {
+  mutable IdentifierInfo *II_fopen, *II_tmpfile, *II_fclose, *II_fread,
+                 *II_fwrite,
+                 *II_fseek, *II_ftell, *II_rewind, *II_fgetpos, *II_fsetpos,
+                 *II_clearerr, *II_feof, *II_ferror, *II_fileno;
+  mutable std::unique_ptr<BuiltinBug> BT_nullfp, BT_illegalwhence,
+      BT_doubleclose, BT_ResourceLeak;
+
+public:
+  StreamChecker()
+    : II_fopen(nullptr), II_tmpfile(nullptr), II_fclose(nullptr),
+      II_fread(nullptr), II_fwrite(nullptr), II_fseek(nullptr),
+      II_ftell(nullptr), II_rewind(nullptr), II_fgetpos(nullptr),
+      II_fsetpos(nullptr), II_clearerr(nullptr), II_feof(nullptr),
+      II_ferror(nullptr), II_fileno(nullptr) {}
+
+  bool evalCall(const CallEvent &Call, CheckerContext &C) const;
+  void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
+
+private:
+  void Fopen(CheckerContext &C, const CallExpr *CE) const;
+  void Tmpfile(CheckerContext &C, const CallExpr *CE) const;
+  void Fclose(CheckerContext &C, const CallExpr *CE) const;
+  void Fread(CheckerContext &C, const CallExpr *CE) const;
+  void Fwrite(CheckerContext &C, const CallExpr *CE) const;
+  void Fseek(CheckerContext &C, const CallExpr *CE) const;
+  void Ftell(CheckerContext &C, const CallExpr *CE) const;
+  void Rewind(CheckerContext &C, const CallExpr *CE) const;
+  void Fgetpos(CheckerContext &C, const CallExpr *CE) const;
+  void Fsetpos(CheckerContext &C, const CallExpr *CE) const;
+  void Clearerr(CheckerContext &C, const CallExpr *CE) const;
+  void Feof(CheckerContext &C, const CallExpr *CE) const;
+  void Ferror(CheckerContext &C, const CallExpr *CE) const;
+  void Fileno(CheckerContext &C, const CallExpr *CE) const;
+
+  void OpenFileAux(CheckerContext &C, const CallExpr *CE) const;
+
+  ProgramStateRef CheckNullStream(SVal SV, ProgramStateRef state,
+                                 CheckerContext &C) const;
+  ProgramStateRef CheckDoubleClose(const CallExpr *CE, ProgramStateRef state,
+                                 CheckerContext &C) const;
+};
+
+} // end anonymous namespace
+
+REGISTER_MAP_WITH_PROGRAMSTATE(StreamMap, SymbolRef, StreamState)
+
+
+bool StreamChecker::evalCall(const CallEvent &Call, CheckerContext &C) const {
+  const auto *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
+  if (!FD || FD->getKind() != Decl::Function)
+    return false;
+
+  const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
+  if (!CE)
+    return false;
+
+  ASTContext &Ctx = C.getASTContext();
+  if (!II_fopen)
+    II_fopen = &Ctx.Idents.get("fopen");
+  if (!II_tmpfile)
+    II_tmpfile = &Ctx.Idents.get("tmpfile");
+  if (!II_fclose)
+    II_fclose = &Ctx.Idents.get("fclose");
+  if (!II_fread)
+    II_fread = &Ctx.Idents.get("fread");
+  if (!II_fwrite)
+    II_fwrite = &Ctx.Idents.get("fwrite");
+  if (!II_fseek)
+    II_fseek = &Ctx.Idents.get("fseek");
+  if (!II_ftell)
+    II_ftell = &Ctx.Idents.get("ftell");
+  if (!II_rewind)
+    II_rewind = &Ctx.Idents.get("rewind");
+  if (!II_fgetpos)
+    II_fgetpos = &Ctx.Idents.get("fgetpos");
+  if (!II_fsetpos)
+    II_fsetpos = &Ctx.Idents.get("fsetpos");
+  if (!II_clearerr)
+    II_clearerr = &Ctx.Idents.get("clearerr");
+  if (!II_feof)
+    II_feof = &Ctx.Idents.get("feof");
+  if (!II_ferror)
+    II_ferror = &Ctx.Idents.get("ferror");
+  if (!II_fileno)
+    II_fileno = &Ctx.Idents.get("fileno");
+
+  if (FD->getIdentifier() == II_fopen) {
+    Fopen(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_tmpfile) {
+    Tmpfile(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fclose) {
+    Fclose(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fread) {
+    Fread(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fwrite) {
+    Fwrite(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fseek) {
+    Fseek(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_ftell) {
+    Ftell(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_rewind) {
+    Rewind(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fgetpos) {
+    Fgetpos(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fsetpos) {
+    Fsetpos(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_clearerr) {
+    Clearerr(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_feof) {
+    Feof(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_ferror) {
+    Ferror(C, CE);
+    return true;
+  }
+  if (FD->getIdentifier() == II_fileno) {
+    Fileno(C, CE);
+    return true;
+  }
+
+  return false;
+}
+
+void StreamChecker::Fopen(CheckerContext &C, const CallExpr *CE) const {
+  OpenFileAux(C, CE);
+}
+
+void StreamChecker::Tmpfile(CheckerContext &C, const CallExpr *CE) const {
+  OpenFileAux(C, CE);
+}
+
+void StreamChecker::OpenFileAux(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  SValBuilder &svalBuilder = C.getSValBuilder();
+  const LocationContext *LCtx = C.getPredecessor()->getLocationContext();
+  DefinedSVal RetVal = svalBuilder.conjureSymbolVal(nullptr, CE, LCtx,
+                                                    C.blockCount())
+      .castAs<DefinedSVal>();
+  state = state->BindExpr(CE, C.getLocationContext(), RetVal);
+
+  ConstraintManager &CM = C.getConstraintManager();
+  // Bifurcate the state into two: one with a valid FILE* pointer, the other
+  // with a NULL.
+  ProgramStateRef stateNotNull, stateNull;
+  std::tie(stateNotNull, stateNull) = CM.assumeDual(state, RetVal);
+
+  if (SymbolRef Sym = RetVal.getAsSymbol()) {
+    // if RetVal is not NULL, set the symbol's state to Opened.
+    stateNotNull =
+      stateNotNull->set<StreamMap>(Sym,StreamState::getOpened(CE));
+    stateNull =
+      stateNull->set<StreamMap>(Sym, StreamState::getOpenFailed(CE));
+
+    C.addTransition(stateNotNull);
+    C.addTransition(stateNull);
+  }
+}
+
+void StreamChecker::Fclose(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = CheckDoubleClose(CE, C.getState(), C);
+  if (state)
+    C.addTransition(state);
+}
+
+void StreamChecker::Fread(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(3)), state, C))
+    return;
+}
+
+void StreamChecker::Fwrite(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(3)), state, C))
+    return;
+}
+
+void StreamChecker::Fseek(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!(state = CheckNullStream(C.getSVal(CE->getArg(0)), state, C)))
+    return;
+  // Check the legality of the 'whence' argument of 'fseek'.
+  SVal Whence = state->getSVal(CE->getArg(2), C.getLocationContext());
+  Optional<nonloc::ConcreteInt> CI = Whence.getAs<nonloc::ConcreteInt>();
+
+  if (!CI)
+    return;
+
+  int64_t x = CI->getValue().getSExtValue();
+  if (x >= 0 && x <= 2)
+    return;
+
+  if (ExplodedNode *N = C.generateNonFatalErrorNode(state)) {
+    if (!BT_illegalwhence)
+      BT_illegalwhence.reset(
+          new BuiltinBug(this, "Illegal whence argument",
+                         "The whence argument to fseek() should be "
+                         "SEEK_SET, SEEK_END, or SEEK_CUR."));
+    C.emitReport(llvm::make_unique<BugReport>(
+        *BT_illegalwhence, BT_illegalwhence->getDescription(), N));
+  }
+}
+
+void StreamChecker::Ftell(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Fgetpos(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Fsetpos(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Clearerr(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Feof(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Ferror(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+void StreamChecker::Fileno(CheckerContext &C, const CallExpr *CE) const {
+  ProgramStateRef state = C.getState();
+  if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
+    return;
+}
+
+ProgramStateRef StreamChecker::CheckNullStream(SVal SV, ProgramStateRef state,
+                                    CheckerContext &C) const {
+  Optional<DefinedSVal> DV = SV.getAs<DefinedSVal>();
+  if (!DV)
+    return nullptr;
+
+  ConstraintManager &CM = C.getConstraintManager();
+  ProgramStateRef stateNotNull, stateNull;
+  std::tie(stateNotNull, stateNull) = CM.assumeDual(state, *DV);
+
+  if (!stateNotNull && stateNull) {
+    if (ExplodedNode *N = C.generateErrorNode(stateNull)) {
+      if (!BT_nullfp)
+        BT_nullfp.reset(new BuiltinBug(this, "NULL stream pointer",
+                                       "Stream pointer might be NULL."));
+      C.emitReport(llvm::make_unique<BugReport>(
+          *BT_nullfp, BT_nullfp->getDescription(), N));
+    }
+    return nullptr;
+  }
+  return stateNotNull;
+}
+
+ProgramStateRef StreamChecker::CheckDoubleClose(const CallExpr *CE,
+                                               ProgramStateRef state,
+                                               CheckerContext &C) const {
+  SymbolRef Sym = C.getSVal(CE->getArg(0)).getAsSymbol();
+  if (!Sym)
+    return state;
+
+  const StreamState *SS = state->get<StreamMap>(Sym);
+
+  // If the file stream is not tracked, return.
+  if (!SS)
+    return state;
+
+  // Check: Double close a File Descriptor could cause undefined behaviour.
+  // Conforming to man-pages
+  if (SS->isClosed()) {
+    ExplodedNode *N = C.generateErrorNode();
+    if (N) {
+      if (!BT_doubleclose)
+        BT_doubleclose.reset(new BuiltinBug(
+            this, "Double fclose", "Try to close a file Descriptor already"
+                                   " closed. Cause undefined behaviour."));
+      C.emitReport(llvm::make_unique<BugReport>(
+          *BT_doubleclose, BT_doubleclose->getDescription(), N));
+    }
+    return nullptr;
+  }
+
+  // Close the File Descriptor.
+  return state->set<StreamMap>(Sym, StreamState::getClosed(CE));
+}
+
+void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
+                                     CheckerContext &C) const {
+  ProgramStateRef state = C.getState();
+
+  // TODO: Clean up the state.
+  const StreamMapTy &Map = state->get<StreamMap>();
+  for (const auto &I: Map) {
+    SymbolRef Sym = I.first;
+    const StreamState &SS = I.second;
+    if (!SymReaper.isDead(Sym) || !SS.isOpened())
+      continue;
+
+    ExplodedNode *N = C.generateErrorNode();
+    if (!N)
+      return;
+
+    if (!BT_ResourceLeak)
+      BT_ResourceLeak.reset(
+          new BuiltinBug(this, "Resource Leak",
+                         "Opened File never closed. Potential Resource leak."));
+    C.emitReport(llvm::make_unique<BugReport>(
+        *BT_ResourceLeak, BT_ResourceLeak->getDescription(), N));
+  }
+}
+
+void ento::registerStreamChecker(CheckerManager &mgr) {
+  mgr.registerChecker<StreamChecker>();
+}
+
+bool ento::shouldRegisterStreamChecker(const LangOptions &LO) {
+  return true;
+}