[clang-tidy] Add a close-on-exec check on inotify_init1() in Android module.

[yawanng]

Summary

inotify_init1() is better to set IN_CLOEXEC flag to avoid file descriptor leakage.

[Eugene.Zelenko]

docs/ReleaseNotes.rst

60 ↗

(On Diff #106462)

Please sort checks in alphabetical order.

[alexfh]

See the comment on D35372.

[hokein]

clang-tidy/android/CloexecInotifyInit1Check.cpp

28 ↗

(On Diff #110649)

nit: /*MarcoFlag=*/

test/clang-tidy/android-cloexec-inotify-init1.cpp

19 ↗

(On Diff #110649)

The same, trailing ;.

[hokein]

LGTM

clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp

 //===--- AndroidTidyModule.cpp - clang-tidy--------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "../ClangTidy.h"
 #include "../ClangTidyModule.h"
 #include "../ClangTidyModuleRegistry.h"
 #include "CloexecCreatCheck.h"
 #include "CloexecDupCheck.h"
 #include "CloexecFopenCheck.h"
+#include "CloexecInotifyInit1Check.h"
 #include "CloexecInotifyInitCheck.h"
 #include "CloexecMemfdCreateCheck.h"
 #include "CloexecOpenCheck.h"
 #include "CloexecSocketCheck.h"
 
 using namespace clang::ast_matchers;
 
 namespace clang {
 namespace tidy {
 namespace android {
 
 /// This module is for Android specific checks.
 class AndroidModule : public ClangTidyModule {
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
     CheckFactories.registerCheck<CloexecCreatCheck>("android-cloexec-creat");
     CheckFactories.registerCheck<CloexecDupCheck>("android-cloexec-dup");
     CheckFactories.registerCheck<CloexecFopenCheck>("android-cloexec-fopen");
     CheckFactories.registerCheck<CloexecInotifyInitCheck>(
         "android-cloexec-inotify-init");
+    CheckFactories.registerCheck<CloexecInotifyInit1Check>(
+        "android-cloexec-inotify-init1");
     CheckFactories.registerCheck<CloexecMemfdCreateCheck>(
         "android-cloexec-memfd-create");
     CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");
     CheckFactories.registerCheck<CloexecSocketCheck>("android-cloexec-socket");
   }
 };
 
 // Register the AndroidTidyModule using this statically initialized variable.

clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS support)
 
 add_clang_library(clangTidyAndroidModule
   AndroidTidyModule.cpp
   CloexecCheck.cpp
   CloexecCreatCheck.cpp
   CloexecDupCheck.cpp
   CloexecFopenCheck.cpp
+  CloexecInotifyInit1Check.cpp
   CloexecInotifyInitCheck.cpp
   CloexecMemfdCreateCheck.cpp
   CloexecOpenCheck.cpp
   CloexecSocketCheck.cpp
 
   LINK_LIBS
   clangAST
   clangASTMatchers
   clangBasic
   clangLex
   clangTidy
   clangTidyUtils
   )

clang-tools-extra/trunk/clang-tidy/android/CloexecInotifyInit1Check.h

+//===--- CloexecInotifyInit1Check.h - clang-tidy-----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT1_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT1_H
+
+#include "CloexecCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Finds code that uses inotify_init1() without using the IN_CLOEXEC flag.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-inotify-init1.html
+class CloexecInotifyInit1Check : public CloexecCheck {
+public:
+  CloexecInotifyInit1Check(StringRef Name, ClangTidyContext *Context)
+      : CloexecCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT1_H

clang-tools-extra/trunk/clang-tidy/android/CloexecInotifyInit1Check.cpp

+//===--- CloexecInotifyInit1Check.cpp - clang-tidy-------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CloexecInotifyInit1Check.h"
+#include "../utils/ASTUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+void CloexecInotifyInit1Check::registerMatchers(MatchFinder *Finder) {
+  registerMatchersImpl(
+      Finder, functionDecl(returns(isInteger()), hasName("inotify_init1"),
+                           hasParameter(0, hasType(isInteger()))));
+}
+
+void CloexecInotifyInit1Check::check(const MatchFinder::MatchResult &Result) {
+  insertMacroFlag(Result, /*MarcoFlag=*/"IN_CLOEXEC", /*ArgPos=*/0);
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang

clang-tools-extra/trunk/docs/ReleaseNotes.rst

- New `bugprone-integer-division
   cause unintended loss of precision.
 
 - New `hicpp-exception-baseclass
   <http://clang.llvm.org/extra/clang-tidy/checks/hicpp-exception-baseclass.html>`_ check
 
   Ensures that all exception will be instances of ``std::exception`` and classes 
   that are derived from it.
 
+- New `android-cloexec-inotify-init1
+  <http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-inotify-init1.html>`_ check
+
+  Checks if the required file flag ``IN_CLOEXEC`` is present in the argument of
+  ``inotify_init1()``.
+
 - New `readability-static-accessed-through-instance
   <http://clang.llvm.org/extra/clang-tidy/checks/readability-static-accessed-through-instance.html>`_ check
 
   Finds member expressions that access static members through instances and
   replaces them with uses of the appropriate qualified-id.
 
 - Added `modernize-use-emplace.IgnoreImplicitConstructors
   <http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-emplace.html#cmdoption-arg-IgnoreImplicitConstructors>`_

clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-inotify-init1.rst

+.. title:: clang-tidy - android-cloexec-inotify-init1
+
+android-cloexec-inotify-init1
+=============================
+
+``inotify_init1()`` should include ``IN_CLOEXEC`` in its type argument to avoid the
+file descriptor leakage. Without this flag, an opened sensitive file would
+remain open across a fork+exec to a lower-privileged SELinux domain.
+
+Examples:
+
+.. code-block:: c++
+
+  inotify_init1(IN_NONBLOCK);
+
+  // becomes
+
+  inotify_init1(IN_NONBLOCK | IN_CLOEXEC);

clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst

 .. title:: clang-tidy - Clang-Tidy Checks
 
 Clang-Tidy Checks
 =================
 
 .. toctree::
    android-cloexec-creat
    android-cloexec-dup
    android-cloexec-fopen
    android-cloexec-inotify-init
+   android-cloexec-inotify-init1
    android-cloexec-memfd-create
    android-cloexec-open
    android-cloexec-socket
    boost-use-to-string
    bugprone-integer-division
    bugprone-suspicious-memset-usage
    bugprone-undefined-memory-manipulation
    cert-dcl03-c (redirects to misc-static-assert) <cert-dcl03-c>

clang-tools-extra/trunk/test/clang-tidy/android-cloexec-inotify-init1.cpp

+// RUN: %check_clang_tidy %s android-cloexec-inotify-init1 %t
+
+#define IN_NONBLOCK 1
+#define __O_CLOEXEC 3
+#define IN_CLOEXEC __O_CLOEXEC
+#define TEMP_FAILURE_RETRY(exp) \
+  ({                            \
+    int _rc;                    \
+    do {                        \
+      _rc = (exp);              \
+    } while (_rc == -1);        \
+  })
+
+extern "C" int inotify_init1(int flags);
+
+void a() {
+  inotify_init1(IN_NONBLOCK);
+  // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: 'inotify_init1' should use IN_CLOEXEC where possible [android-cloexec-inotify-init1]
+  // CHECK-FIXES: inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
+  TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK));
+  // CHECK-MESSAGES: :[[@LINE-1]]:47: warning: 'inotify_init1'
+  // CHECK-FIXES: TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK | IN_CLOEXEC));
+}
+
+void f() {
+  inotify_init1(0);
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'inotify_init1'
+  // CHECK-FIXES: inotify_init1(IN_CLOEXEC);
+  TEMP_FAILURE_RETRY(inotify_init1(0));
+  // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: 'inotify_init1'
+  // CHECK-FIXES: TEMP_FAILURE_RETRY(inotify_init1(IN_CLOEXEC));
+
+  int flag = 1;
+  inotify_init1(flag);
+  TEMP_FAILURE_RETRY(inotify_init1(flag));
+}
+
+namespace i {
+int inotify_init1(int flags);
+
+void d() {
+  inotify_init1(IN_NONBLOCK);
+  TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK));
+}
+
+} // namespace i
+
+void e() {
+  inotify_init1(IN_CLOEXEC);
+  TEMP_FAILURE_RETRY(inotify_init1(IN_CLOEXEC));
+  inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
+  TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK | IN_CLOEXEC));
+}
+
+class G {
+public:
+  int inotify_init1(int flags);
+  void d() {
+    inotify_init1(IN_CLOEXEC);
+    TEMP_FAILURE_RETRY(inotify_init1(IN_CLOEXEC));
+    inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
+    TEMP_FAILURE_RETRY(inotify_init1(IN_NONBLOCK | IN_CLOEXEC));
+  }
+};