[clang] [analyzer] Note last "fclose" call from "ensureStreamOpened" (PR #109112)
Balazs Benics via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 18 02:33:24 PDT 2024
https://github.com/steakhal created https://github.com/llvm/llvm-project/pull/109112
Patch by Arseniy Zaostrovnykh!
>From 408ee82b1ee3ae15302b2a0dde9faded3e43bf0f Mon Sep 17 00:00:00 2001
From: Arseniy Zaostrovnykh <necto.ne at gmail.com>
Date: Wed, 18 Sep 2024 11:30:10 +0200
Subject: [PATCH] [analyzer] Note last "fclose" call from "ensureStreamOpened"
Patch by Arseniy Zaostrovnykh!
---
.../StaticAnalyzer/Checkers/StreamChecker.cpp | 49 +++++++++++++++++--
clang/test/Analysis/stream-note.c | 9 ++++
2 files changed, 54 insertions(+), 4 deletions(-)
diff --git a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
index 8bb7880a3cc283..c0f3591662b418 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
@@ -1835,6 +1835,46 @@ StreamChecker::ensureStreamNonNull(SVal StreamVal, const Expr *StreamE,
return StateNotNull;
}
+namespace {
+class StreamClosedVisitor final : public BugReporterVisitor {
+ const SymbolRef StreamSym;
+ bool Satisfied = false;
+
+public:
+ explicit StreamClosedVisitor(SymbolRef StreamSym) : StreamSym(StreamSym) {}
+
+ static void *getTag() {
+ static int Tag = 0;
+ return &Tag;
+ }
+
+ void Profile(llvm::FoldingSetNodeID &ID) const override {
+ ID.AddPointer(getTag());
+ ID.AddPointer(StreamSym);
+ }
+
+ PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
+ BugReporterContext &BRC,
+ PathSensitiveBugReport &BR) override {
+ if (Satisfied)
+ return nullptr;
+ const StreamState *PredSS =
+ N->getFirstPred()->getState()->get<StreamMap>(StreamSym);
+ if (PredSS && PredSS->isClosed())
+ return nullptr;
+
+ const Stmt *S = N->getStmtForDiagnostics();
+ if (!S)
+ return nullptr;
+ Satisfied = true;
+ PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
+ N->getLocationContext());
+ llvm::StringLiteral Msg = "Stream is closed here";
+ return std::make_shared<PathDiagnosticEventPiece>(Pos, Msg);
+ }
+};
+} // namespace
+
ProgramStateRef StreamChecker::ensureStreamOpened(SVal StreamVal,
CheckerContext &C,
ProgramStateRef State) const {
@@ -1849,11 +1889,12 @@ ProgramStateRef StreamChecker::ensureStreamOpened(SVal StreamVal,
if (SS->isClosed()) {
// Using a stream pointer after 'fclose' causes undefined behavior
// according to cppreference.com .
- ExplodedNode *N = C.generateErrorNode();
- if (N) {
- C.emitReport(std::make_unique<PathSensitiveBugReport>(
+ if (ExplodedNode *N = C.generateErrorNode()) {
+ auto R = std::make_unique<PathSensitiveBugReport>(
BT_UseAfterClose,
- "Stream might be already closed. Causes undefined behaviour.", N));
+ "Stream might be already closed. Causes undefined behaviour.", N);
+ R->addVisitor<StreamClosedVisitor>(Sym);
+ C.emitReport(std::move(R));
return nullptr;
}
diff --git a/clang/test/Analysis/stream-note.c b/clang/test/Analysis/stream-note.c
index 3aef707d50056e..02251e2e12d6a1 100644
--- a/clang/test/Analysis/stream-note.c
+++ b/clang/test/Analysis/stream-note.c
@@ -264,3 +264,12 @@ void error_fseek_read_eof(void) {
fgetc(F); // no warning
fclose(F);
}
+
+void check_note_at_use_after_close(void) {
+ FILE *F = tmpfile();
+ if (!F) // expected-note {{'F' is non-null}} expected-note {{Taking false branch}}
+ return;
+ fclose(F); // expected-note {{Stream is closed here}}
+ rewind(F); // expected-warning {{Stream might be already closed. Causes undefined behaviour}}
+ // expected-note at -1 {{Stream might be already closed. Causes undefined behaviour}}
+}
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