jcai19 created this revision.
Herald added subscribers: cfe-commits, xazax.hun, mgorny, srhines.
Herald added a project: clang.
pipe2() is better to set O_CLOEXEC flag to avoid file descriptor leakage.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D62049
Files:
clang-tools-extra/clang-tidy/android/AndroidTidyModule.cpp
clang-tools-extra/clang-tidy/android/CMakeLists.txt
clang-tools-extra/clang-tidy/android/CloexecPipe2Check.cpp
clang-tools-extra/clang-tidy/android/CloexecPipe2Check.h
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/android-cloexec-pipe2.rst
clang-tools-extra/docs/clang-tidy/checks/list.rst
clang-tools-extra/test/clang-tidy/android-cloexec-pipe2.cpp
Index: clang-tools-extra/test/clang-tidy/android-cloexec-pipe2.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/android-cloexec-pipe2.cpp
@@ -0,0 +1,68 @@
+// RUN: %check_clang_tidy %s android-cloexec-pipe2 %t
+
+#define O_NONBLOCK 1
+#define __O_CLOEXEC 3
+#define O_CLOEXEC __O_CLOEXEC
+#define TEMP_FAILURE_RETRY(exp) \
+ ({ \
+ int _rc; \
+ do { \
+ _rc = (exp); \
+ } while (_rc == -1); \
+ })
+#define NULL 0
+
+extern "C" int pipe2(int pipefd[2], int flags);
+
+void a() {
+ int pipefd[2];
+ pipe2(pipefd, O_NONBLOCK);
+ // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: 'pipe2' should use O_CLOEXEC where possible [android-cloexec-pipe2]
+ // CHECK-FIXES: pipe2(pipefd, O_NONBLOCK | O_CLOEXEC);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, O_NONBLOCK));
+ // CHECK-MESSAGES: :[[@LINE-1]]:46: warning: 'pipe2'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(pipe2(pipefd, O_NONBLOCK | O_CLOEXEC));
+}
+
+void f() {
+ int pipefd[2];
+ pipe2(pipefd, 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'pipe2'
+ // CHECK-FIXES: pipe2(pipefd, 3 | O_CLOEXEC);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, 3));
+ // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: 'pipe2'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(pipe2(pipefd, 3 | O_CLOEXEC));
+
+ int flag = O_NONBLOCK;
+ pipe2(pipefd, flag);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, flag));
+}
+
+namespace i {
+int pipe2(int pipefd[2], int flags);
+
+void d() {
+ int pipefd[2];
+ pipe2(pipefd, O_NONBLOCK);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, O_NONBLOCK));
+}
+
+} // namespace i
+
+void e() {
+ int pipefd[2];
+ pipe2(pipefd, O_CLOEXEC);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
+ pipe2(pipefd, O_NONBLOCK | O_CLOEXEC);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, O_NONBLOCK | O_CLOEXEC));
+}
+
+class G {
+public:
+ int pipe2(int pipefd[2], int flags);
+ void d() {
+ int pipefd[2];
+ pipe2(pipefd, O_NONBLOCK);
+ TEMP_FAILURE_RETRY(pipe2(pipefd, O_NONBLOCK));
+ }
+};
Index: clang-tools-extra/docs/clang-tidy/checks/list.rst
===================================================================
--- clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -32,6 +32,7 @@
android-cloexec-inotify-init1
android-cloexec-memfd-create
android-cloexec-open
+ android-cloexec-pipe2
android-cloexec-socket
android-comparison-in-temp-failure-retry
boost-use-to-string
Index: clang-tools-extra/docs/clang-tidy/checks/android-cloexec-pipe2.rst
===================================================================
--- /dev/null
+++ clang-tools-extra/docs/clang-tidy/checks/android-cloexec-pipe2.rst
@@ -0,0 +1,19 @@
+.. title:: clang-tidy - android-cloexec-pipe2
+
+android-cloexec-pipe2
+=====================
+
+Checks if the required file flag ``O_CLOEXEC`` is present in the argument of
+``pipe2()``. ``pipe2()`` should include ``O_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++
+
+ pipe2(pipefd, O_NONBLOCK);
+
+ // becomes
+
+ pipe2(pipefd, O_CLOEXEC);
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -101,6 +101,12 @@
Finds and fixes ``absl::Time`` subtraction expressions to do subtraction
in the Time domain instead of the numeric domain.
+- New :doc:`android-cloexec-pipe
+ <clang-tidy/checks/android-cloexec-pipe2>` check.
+
+ Checks if the required file flag ``O_CLOEXEC`` is present in the argument of
+ ``pipe2()``.
+
- New :doc:`bugprone-unhandled-self-assignment
<clang-tidy/checks/bugprone-unhandled-self-assignment>` check.
Index: clang-tools-extra/clang-tidy/android/CloexecPipe2Check.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/android/CloexecPipe2Check.h
@@ -0,0 +1,34 @@
+//===--- CloexecPipe2Check.h - clang-tidy----------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_PIPE2_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_PIPE2_H
+
+#include "CloexecCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Finds code that uses pipe2() without using the O_CLOEXEC flag.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-pipe2.html
+class CloexecPipe2Check : public CloexecCheck {
+public:
+ CloexecPipe2Check(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_PIPE2_H
Index: clang-tools-extra/clang-tidy/android/CloexecPipe2Check.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/android/CloexecPipe2Check.cpp
@@ -0,0 +1,33 @@
+//===--- CloexecPipe2Check.cpp - clang-tidy------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "CloexecPipe2Check.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 CloexecPipe2Check::registerMatchers(MatchFinder *Finder) {
+ registerMatchersImpl(Finder,
+ functionDecl(returns(isInteger()), hasName("pipe2"),
+ hasParameter(0, hasType(pointsTo(isInteger()))),
+ hasParameter(1, hasType(isInteger()))));
+}
+
+void CloexecPipe2Check::check(const MatchFinder::MatchResult &Result) {
+ insertMacroFlag(Result, /*MacroFlag=*/"O_CLOEXEC", /*ArgPos=*/1);
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Index: clang-tools-extra/clang-tidy/android/CMakeLists.txt
===================================================================
--- clang-tools-extra/clang-tidy/android/CMakeLists.txt
+++ clang-tools-extra/clang-tidy/android/CMakeLists.txt
@@ -14,6 +14,7 @@
CloexecInotifyInitCheck.cpp
CloexecMemfdCreateCheck.cpp
CloexecOpenCheck.cpp
+ CloexecPipe2Check.cpp
CloexecSocketCheck.cpp
ComparisonInTempFailureRetryCheck.cpp
Index: clang-tools-extra/clang-tidy/android/AndroidTidyModule.cpp
===================================================================
--- clang-tools-extra/clang-tidy/android/AndroidTidyModule.cpp
+++ clang-tools-extra/clang-tidy/android/AndroidTidyModule.cpp
@@ -20,6 +20,7 @@
#include "CloexecInotifyInitCheck.h"
#include "CloexecMemfdCreateCheck.h"
#include "CloexecOpenCheck.h"
+#include "CloexecPipe2Check.h"
#include "CloexecSocketCheck.h"
#include "ComparisonInTempFailureRetryCheck.h"
@@ -49,6 +50,7 @@
CheckFactories.registerCheck<CloexecMemfdCreateCheck>(
"android-cloexec-memfd-create");
CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");
+ CheckFactories.registerCheck<CloexecPipe2Check>("android-cloexec-pipe2");
CheckFactories.registerCheck<CloexecSocketCheck>("android-cloexec-socket");
CheckFactories.registerCheck<ComparisonInTempFailureRetryCheck>(
"android-comparison-in-temp-failure-retry");
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