1 //===-- StreamChecker.cpp -----------------------------------------*- C++ -*--//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file defines checkers that model and check stream handling functions.
11 //===----------------------------------------------------------------------===//
13 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
14 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
15 #include "clang/StaticAnalyzer/Core/Checker.h"
16 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
23 using namespace clang;
29 enum Kind { Opened, Closed, OpenFailed, Escaped } K;
32 StreamState(Kind k, const Stmt *s) : K(k), S(s) {}
34 bool isOpened() const { return K == Opened; }
35 bool isClosed() const { return K == Closed; }
36 //bool isOpenFailed() const { return K == OpenFailed; }
37 //bool isEscaped() const { return K == Escaped; }
39 bool operator==(const StreamState &X) const {
40 return K == X.K && S == X.S;
43 static StreamState getOpened(const Stmt *s) { return StreamState(Opened, s); }
44 static StreamState getClosed(const Stmt *s) { return StreamState(Closed, s); }
45 static StreamState getOpenFailed(const Stmt *s) {
46 return StreamState(OpenFailed, s);
48 static StreamState getEscaped(const Stmt *s) {
49 return StreamState(Escaped, s);
52 void Profile(llvm::FoldingSetNodeID &ID) const {
58 class StreamChecker : public Checker<eval::Call,
59 check::DeadSymbols > {
60 mutable IdentifierInfo *II_fopen, *II_tmpfile, *II_fclose, *II_fread,
62 *II_fseek, *II_ftell, *II_rewind, *II_fgetpos, *II_fsetpos,
63 *II_clearerr, *II_feof, *II_ferror, *II_fileno;
64 mutable std::unique_ptr<BuiltinBug> BT_nullfp, BT_illegalwhence,
65 BT_doubleclose, BT_ResourceLeak;
69 : II_fopen(nullptr), II_tmpfile(nullptr), II_fclose(nullptr),
70 II_fread(nullptr), II_fwrite(nullptr), II_fseek(nullptr),
71 II_ftell(nullptr), II_rewind(nullptr), II_fgetpos(nullptr),
72 II_fsetpos(nullptr), II_clearerr(nullptr), II_feof(nullptr),
73 II_ferror(nullptr), II_fileno(nullptr) {}
75 bool evalCall(const CallEvent &Call, CheckerContext &C) const;
76 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
79 void Fopen(CheckerContext &C, const CallExpr *CE) const;
80 void Tmpfile(CheckerContext &C, const CallExpr *CE) const;
81 void Fclose(CheckerContext &C, const CallExpr *CE) const;
82 void Fread(CheckerContext &C, const CallExpr *CE) const;
83 void Fwrite(CheckerContext &C, const CallExpr *CE) const;
84 void Fseek(CheckerContext &C, const CallExpr *CE) const;
85 void Ftell(CheckerContext &C, const CallExpr *CE) const;
86 void Rewind(CheckerContext &C, const CallExpr *CE) const;
87 void Fgetpos(CheckerContext &C, const CallExpr *CE) const;
88 void Fsetpos(CheckerContext &C, const CallExpr *CE) const;
89 void Clearerr(CheckerContext &C, const CallExpr *CE) const;
90 void Feof(CheckerContext &C, const CallExpr *CE) const;
91 void Ferror(CheckerContext &C, const CallExpr *CE) const;
92 void Fileno(CheckerContext &C, const CallExpr *CE) const;
94 void OpenFileAux(CheckerContext &C, const CallExpr *CE) const;
96 ProgramStateRef CheckNullStream(SVal SV, ProgramStateRef state,
97 CheckerContext &C) const;
98 ProgramStateRef CheckDoubleClose(const CallExpr *CE, ProgramStateRef state,
99 CheckerContext &C) const;
102 } // end anonymous namespace
104 REGISTER_MAP_WITH_PROGRAMSTATE(StreamMap, SymbolRef, StreamState)
107 bool StreamChecker::evalCall(const CallEvent &Call, CheckerContext &C) const {
108 const auto *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
109 if (!FD || FD->getKind() != Decl::Function)
112 const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
116 ASTContext &Ctx = C.getASTContext();
118 II_fopen = &Ctx.Idents.get("fopen");
120 II_tmpfile = &Ctx.Idents.get("tmpfile");
122 II_fclose = &Ctx.Idents.get("fclose");
124 II_fread = &Ctx.Idents.get("fread");
126 II_fwrite = &Ctx.Idents.get("fwrite");
128 II_fseek = &Ctx.Idents.get("fseek");
130 II_ftell = &Ctx.Idents.get("ftell");
132 II_rewind = &Ctx.Idents.get("rewind");
134 II_fgetpos = &Ctx.Idents.get("fgetpos");
136 II_fsetpos = &Ctx.Idents.get("fsetpos");
138 II_clearerr = &Ctx.Idents.get("clearerr");
140 II_feof = &Ctx.Idents.get("feof");
142 II_ferror = &Ctx.Idents.get("ferror");
144 II_fileno = &Ctx.Idents.get("fileno");
146 if (FD->getIdentifier() == II_fopen) {
150 if (FD->getIdentifier() == II_tmpfile) {
154 if (FD->getIdentifier() == II_fclose) {
158 if (FD->getIdentifier() == II_fread) {
162 if (FD->getIdentifier() == II_fwrite) {
166 if (FD->getIdentifier() == II_fseek) {
170 if (FD->getIdentifier() == II_ftell) {
174 if (FD->getIdentifier() == II_rewind) {
178 if (FD->getIdentifier() == II_fgetpos) {
182 if (FD->getIdentifier() == II_fsetpos) {
186 if (FD->getIdentifier() == II_clearerr) {
190 if (FD->getIdentifier() == II_feof) {
194 if (FD->getIdentifier() == II_ferror) {
198 if (FD->getIdentifier() == II_fileno) {
206 void StreamChecker::Fopen(CheckerContext &C, const CallExpr *CE) const {
210 void StreamChecker::Tmpfile(CheckerContext &C, const CallExpr *CE) const {
214 void StreamChecker::OpenFileAux(CheckerContext &C, const CallExpr *CE) const {
215 ProgramStateRef state = C.getState();
216 SValBuilder &svalBuilder = C.getSValBuilder();
217 const LocationContext *LCtx = C.getPredecessor()->getLocationContext();
218 DefinedSVal RetVal = svalBuilder.conjureSymbolVal(nullptr, CE, LCtx,
220 .castAs<DefinedSVal>();
221 state = state->BindExpr(CE, C.getLocationContext(), RetVal);
223 ConstraintManager &CM = C.getConstraintManager();
224 // Bifurcate the state into two: one with a valid FILE* pointer, the other
226 ProgramStateRef stateNotNull, stateNull;
227 std::tie(stateNotNull, stateNull) = CM.assumeDual(state, RetVal);
229 if (SymbolRef Sym = RetVal.getAsSymbol()) {
230 // if RetVal is not NULL, set the symbol's state to Opened.
232 stateNotNull->set<StreamMap>(Sym,StreamState::getOpened(CE));
234 stateNull->set<StreamMap>(Sym, StreamState::getOpenFailed(CE));
236 C.addTransition(stateNotNull);
237 C.addTransition(stateNull);
241 void StreamChecker::Fclose(CheckerContext &C, const CallExpr *CE) const {
242 ProgramStateRef state = CheckDoubleClose(CE, C.getState(), C);
244 C.addTransition(state);
247 void StreamChecker::Fread(CheckerContext &C, const CallExpr *CE) const {
248 ProgramStateRef state = C.getState();
249 if (!CheckNullStream(C.getSVal(CE->getArg(3)), state, C))
253 void StreamChecker::Fwrite(CheckerContext &C, const CallExpr *CE) const {
254 ProgramStateRef state = C.getState();
255 if (!CheckNullStream(C.getSVal(CE->getArg(3)), state, C))
259 void StreamChecker::Fseek(CheckerContext &C, const CallExpr *CE) const {
260 ProgramStateRef state = C.getState();
261 if (!(state = CheckNullStream(C.getSVal(CE->getArg(0)), state, C)))
263 // Check the legality of the 'whence' argument of 'fseek'.
264 SVal Whence = state->getSVal(CE->getArg(2), C.getLocationContext());
265 Optional<nonloc::ConcreteInt> CI = Whence.getAs<nonloc::ConcreteInt>();
270 int64_t x = CI->getValue().getSExtValue();
271 if (x >= 0 && x <= 2)
274 if (ExplodedNode *N = C.generateNonFatalErrorNode(state)) {
275 if (!BT_illegalwhence)
276 BT_illegalwhence.reset(
277 new BuiltinBug(this, "Illegal whence argument",
278 "The whence argument to fseek() should be "
279 "SEEK_SET, SEEK_END, or SEEK_CUR."));
280 C.emitReport(llvm::make_unique<BugReport>(
281 *BT_illegalwhence, BT_illegalwhence->getDescription(), N));
285 void StreamChecker::Ftell(CheckerContext &C, const CallExpr *CE) const {
286 ProgramStateRef state = C.getState();
287 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
291 void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) const {
292 ProgramStateRef state = C.getState();
293 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
297 void StreamChecker::Fgetpos(CheckerContext &C, const CallExpr *CE) const {
298 ProgramStateRef state = C.getState();
299 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
303 void StreamChecker::Fsetpos(CheckerContext &C, const CallExpr *CE) const {
304 ProgramStateRef state = C.getState();
305 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
309 void StreamChecker::Clearerr(CheckerContext &C, const CallExpr *CE) const {
310 ProgramStateRef state = C.getState();
311 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
315 void StreamChecker::Feof(CheckerContext &C, const CallExpr *CE) const {
316 ProgramStateRef state = C.getState();
317 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
321 void StreamChecker::Ferror(CheckerContext &C, const CallExpr *CE) const {
322 ProgramStateRef state = C.getState();
323 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
327 void StreamChecker::Fileno(CheckerContext &C, const CallExpr *CE) const {
328 ProgramStateRef state = C.getState();
329 if (!CheckNullStream(C.getSVal(CE->getArg(0)), state, C))
333 ProgramStateRef StreamChecker::CheckNullStream(SVal SV, ProgramStateRef state,
334 CheckerContext &C) const {
335 Optional<DefinedSVal> DV = SV.getAs<DefinedSVal>();
339 ConstraintManager &CM = C.getConstraintManager();
340 ProgramStateRef stateNotNull, stateNull;
341 std::tie(stateNotNull, stateNull) = CM.assumeDual(state, *DV);
343 if (!stateNotNull && stateNull) {
344 if (ExplodedNode *N = C.generateErrorNode(stateNull)) {
346 BT_nullfp.reset(new BuiltinBug(this, "NULL stream pointer",
347 "Stream pointer might be NULL."));
348 C.emitReport(llvm::make_unique<BugReport>(
349 *BT_nullfp, BT_nullfp->getDescription(), N));
356 ProgramStateRef StreamChecker::CheckDoubleClose(const CallExpr *CE,
357 ProgramStateRef state,
358 CheckerContext &C) const {
359 SymbolRef Sym = C.getSVal(CE->getArg(0)).getAsSymbol();
363 const StreamState *SS = state->get<StreamMap>(Sym);
365 // If the file stream is not tracked, return.
369 // Check: Double close a File Descriptor could cause undefined behaviour.
370 // Conforming to man-pages
371 if (SS->isClosed()) {
372 ExplodedNode *N = C.generateErrorNode();
375 BT_doubleclose.reset(new BuiltinBug(
376 this, "Double fclose", "Try to close a file Descriptor already"
377 " closed. Cause undefined behaviour."));
378 C.emitReport(llvm::make_unique<BugReport>(
379 *BT_doubleclose, BT_doubleclose->getDescription(), N));
384 // Close the File Descriptor.
385 return state->set<StreamMap>(Sym, StreamState::getClosed(CE));
388 void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
389 CheckerContext &C) const {
390 ProgramStateRef state = C.getState();
392 // TODO: Clean up the state.
393 const StreamMapTy &Map = state->get<StreamMap>();
394 for (const auto &I: Map) {
395 SymbolRef Sym = I.first;
396 const StreamState &SS = I.second;
397 if (!SymReaper.isDead(Sym) || !SS.isOpened())
400 ExplodedNode *N = C.generateErrorNode();
404 if (!BT_ResourceLeak)
405 BT_ResourceLeak.reset(
406 new BuiltinBug(this, "Resource Leak",
407 "Opened File never closed. Potential Resource leak."));
408 C.emitReport(llvm::make_unique<BugReport>(
409 *BT_ResourceLeak, BT_ResourceLeak->getDescription(), N));
413 void ento::registerStreamChecker(CheckerManager &mgr) {
414 mgr.registerChecker<StreamChecker>();
417 bool ento::shouldRegisterStreamChecker(const LangOptions &LO) {