yawanng updated this revision to Diff 106515.
yawanng marked an inline comment as done.
https://reviews.llvm.org/D35372
Files:
clang-tidy/android/AndroidTidyModule.cpp
clang-tidy/android/CMakeLists.txt
clang-tidy/android/CloexecMemfdCreateCheck.cpp
clang-tidy/android/CloexecMemfdCreateCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/android-cloexec-memfd-create.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/android-cloexec-memfd-create.cpp
Index: test/clang-tidy/android-cloexec-memfd-create.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/android-cloexec-memfd-create.cpp
@@ -0,0 +1,63 @@
+// RUN: %check_clang_tidy %s android-cloexec-memfd-create %t
+
+#define MFD_ALLOW_SEALING 1
+#define __O_CLOEXEC 3
+#define MFD_CLOEXEC __O_CLOEXEC
+#define TEMP_FAILURE_RETRY(exp) \
+ ({ \
+ int _rc; \
+ do { \
+ _rc = (exp); \
+ } while (_rc == -1); \
+ })
+#define NULL 0
+
+extern "C" int memfd_create(const char *name, unsigned int flags);
+
+void a() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ // CHECK-MESSAGES: :[[@LINE-1]]:39: warning: 'memfd_create' should use MFD_CLOEXEC where possible [android-cloexec-memfd-create]
+ // CHECK-FIXES: memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC)
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+ // CHECK-MESSAGES: :[[@LINE-1]]:58: warning: 'memfd_create'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC))
+}
+
+void f() {
+ memfd_create(NULL, 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: 'memfd_create'
+ // CHECK-FIXES: memfd_create(NULL, 3 | MFD_CLOEXEC)
+ TEMP_FAILURE_RETRY(memfd_create(NULL, 3));
+ // CHECK-MESSAGES: :[[@LINE-1]]:42: warning: 'memfd_create'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(memfd_create(NULL, 3 | MFD_CLOEXEC))
+
+ int flag = 3;
+ memfd_create(NULL, flag);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, flag));
+}
+
+namespace i {
+int memfd_create(const char *name, unsigned int flags);
+
+void d() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+}
+
+} // namespace i
+
+void e() {
+ memfd_create(NULL, MFD_CLOEXEC);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_CLOEXEC));
+ memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC));
+}
+
+class G {
+public:
+ int memfd_create(const char *name, unsigned int flags);
+ void d() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+ }
+};
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -6,6 +6,7 @@
.. toctree::
android-cloexec-creat
android-cloexec-fopen
+ android-cloexec-memfd-create
android-cloexec-open
android-cloexec-socket
boost-use-to-string
Index: docs/clang-tidy/checks/android-cloexec-memfd-create.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/android-cloexec-memfd-create.rst
@@ -0,0 +1,18 @@
+.. title:: clang-tidy - android-cloexec-memfd-create
+
+android-cloexec-memfd-create
+============================
+
+``memfd_create()`` should include ``MFD_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++
+
+ memfd_create(name, MFD_ALLOW_SEALING);
+
+ // becomes
+
+ memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC);
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -73,6 +73,12 @@
Checks if the required mode ``e`` exists in the mode argument of ``fopen()``.
+- New `android-cloexec-memfd_create
+ <http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-memfd_create.html>`_ check
+
+ Checks if the required file flag ``MFD_CLOEXEC`` is present in the argument of
+ ``memfd_create()``.
+
- New `android-cloexec-socket
<http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-socket.html>`_ check
Index: clang-tidy/android/CloexecMemfdCreateCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecMemfdCreateCheck.h
@@ -0,0 +1,35 @@
+//===--- CloexecMemfdCreateCheck.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_MEMFD_CREATE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_MEMFD_CREATE_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Finds code that uses memfd_create() without using the MFD_CLOEXEC flag.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-memfd-create.html
+class CloexecMemfdCreateCheck : public ClangTidyCheck {
+public:
+ CloexecMemfdCreateCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(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_MEMFD_CREATE_H
Index: clang-tidy/android/CloexecMemfdCreateCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecMemfdCreateCheck.cpp
@@ -0,0 +1,58 @@
+//===--- CloexecMemfdCreateCheck.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 "CloexecMemfdCreateCheck.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 {
+
+static constexpr const char *MFD_CLOEXEC = "MFD_CLOEXEC";
+
+void CloexecMemfdCreateCheck::registerMatchers(MatchFinder *Finder) {
+ auto CharPointerType = hasType(pointerType(pointee(isAnyCharacter())));
+
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(isExternC(), returns(isInteger()),
+ hasName("memfd_create"),
+ hasParameter(0, CharPointerType),
+ hasParameter(1, hasType(isInteger())))
+ .bind("funcDecl")))
+ .bind("memfdCreateFn"),
+ this);
+}
+
+void CloexecMemfdCreateCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>("memfdCreateFn");
+ const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("funcDecl");
+ const Expr *FlagArg = MatchedCall->getArg(1);
+ SourceManager &SM = *Result.SourceManager;
+
+ if (utils::exprHasBitFlagWithSpelling(FlagArg->IgnoreParenCasts(), SM,
+ Result.Context->getLangOpts(),
+ MFD_CLOEXEC))
+ return;
+
+ SourceLocation EndLoc =
+ Lexer::getLocForEndOfToken(SM.getFileLoc(FlagArg->getLocEnd()), 0, SM,
+ Result.Context->getLangOpts());
+
+ diag(EndLoc, "%0 should use %1 where possible")
+ << FD << MFD_CLOEXEC
+ << FixItHint::CreateInsertion(EndLoc, (Twine(" | ") + MFD_CLOEXEC).str());
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/android/CMakeLists.txt
===================================================================
--- clang-tidy/android/CMakeLists.txt
+++ clang-tidy/android/CMakeLists.txt
@@ -4,6 +4,7 @@
AndroidTidyModule.cpp
CloexecCreatCheck.cpp
CloexecFopenCheck.cpp
+ CloexecMemfdCreateCheck.cpp
CloexecOpenCheck.cpp
CloexecSocketCheck.cpp
Index: clang-tidy/android/AndroidTidyModule.cpp
===================================================================
--- clang-tidy/android/AndroidTidyModule.cpp
+++ clang-tidy/android/AndroidTidyModule.cpp
@@ -12,6 +12,7 @@
#include "../ClangTidyModuleRegistry.h"
#include "CloexecCreatCheck.h"
#include "CloexecFopenCheck.h"
+#include "CloexecMemfdCreateCheck.h"
#include "CloexecOpenCheck.h"
#include "CloexecSocketCheck.h"
@@ -27,6 +28,8 @@
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<CloexecCreatCheck>("android-cloexec-creat");
CheckFactories.registerCheck<CloexecFopenCheck>("android-cloexec-fopen");
+ CheckFactories.registerCheck<CloexecMemfdCreateCheck>(
+ "android-cloexec-memfd-create");
CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");
CheckFactories.registerCheck<CloexecSocketCheck>("android-cloexec-socket");
}
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