yawanng updated this revision to Diff 100934.
yawanng edited the summary of this revision.
https://reviews.llvm.org/D33304
Files:
clang-tidy/CMakeLists.txt
clang-tidy/android/AndroidTidyModule.cpp
clang-tidy/android/CMakeLists.txt
clang-tidy/android/FileOpenFlagCheck.cpp
clang-tidy/android/FileOpenFlagCheck.h
clang-tidy/plugin/CMakeLists.txt
clang-tidy/tool/CMakeLists.txt
clang-tidy/tool/ClangTidyMain.cpp
docs/ReleaseNotes.rst
docs/clang-tidy/checks/android-file-open-flag.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/index.rst
test/clang-tidy/android-file-open-flag.cpp
unittests/clang-tidy/CMakeLists.txt
Index: unittests/clang-tidy/CMakeLists.txt
===================================================================
--- unittests/clang-tidy/CMakeLists.txt
+++ unittests/clang-tidy/CMakeLists.txt
@@ -25,6 +25,7 @@
clangFrontend
clangLex
clangTidy
+ clangTidyAndroidModule
clangTidyGoogleModule
clangTidyLLVMModule
clangTidyMiscModule
Index: test/clang-tidy/android-file-open-flag.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/android-file-open-flag.cpp
@@ -0,0 +1,104 @@
+// RUN: %check_clang_tidy %s android-file-open-flag %t
+
+#define O_RDWR 1
+#define O_EXCL 2
+#define __O_CLOEXEC 3
+#define O_CLOEXEC __O_CLOEXEC
+
+extern "C" int open(const char *fn, int flags, ...);
+extern "C" int open64(const char *fn, int flags, ...);
+extern "C" int openat(int dirfd, const char *pathname, int flags, ...);
+
+void a() {
+ open("filename", O_RDWR);
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: open should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_CLOEXEC
+ open("filename", O_RDWR | O_EXCL);
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: open should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_EXCL | O_CLOEXEC
+}
+
+void b() {
+ open64("filename", O_RDWR);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: open64 should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_CLOEXEC
+ open64("filename", O_RDWR | O_EXCL);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: open64 should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_EXCL | O_CLOEXEC
+}
+
+void c() {
+ openat(0, "filename", O_RDWR);
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: openat should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_CLOEXEC
+ openat(0, "filename", O_RDWR | O_EXCL);
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: openat should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: O_RDWR | O_EXCL | O_CLOEXEC
+}
+
+void f() {
+ open("filename", 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: open should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: 3 | O_CLOEXEC
+ open64("filename", 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: open64 should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: 3 | O_CLOEXEC
+ openat(0, "filename", 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: openat should use O_CLOEXEC where possible. [android-file-open-flag]
+ // CHECK-FIXES: 3 | O_CLOEXEC
+
+ int flag = 3;
+ open("filename", flag);
+ // CHECK-MESSAGES-NOT: warning:
+ open64("filename", flag);
+ // CHECK-MESSAGES-NOT: warning:
+ openat(0, "filename", flag);
+ // CHECK-MESSAGES-NOT: warning:
+}
+
+namespace i {
+int open(const char *pathname, int flags, ...);
+int open64(const char *pathname, int flags, ...);
+int openat(int dirfd, const char *pathname, int flags, ...);
+
+void d() {
+ open("filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+ open64("filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+ openat(0, "filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+}
+
+} // namespace i
+
+void e() {
+ open("filename", O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+ open("filename", O_RDWR | O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+ open64("filename", O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+ open64("filename", O_RDWR | O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+ openat(0, "filename", O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+ openat(0, "filename", O_RDWR | O_CLOEXEC);
+ // CHECK-MESSAGES-NOT: warning:
+}
+
+class G {
+public:
+ int open(const char *pathname, int flags, ...);
+ int open64(const char *pathname, int flags, ...);
+ int openat(int dirfd, const char *pathname, int flags, ...);
+
+ void h() {
+ open("filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+ open64("filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+ openat(0, "filename", O_RDWR);
+ // CHECK-MESSAGES-NOT: warning:
+ }
+};
Index: docs/clang-tidy/index.rst
===================================================================
--- docs/clang-tidy/index.rst
+++ docs/clang-tidy/index.rst
@@ -55,6 +55,7 @@
====================== =========================================================
Name prefix Description
====================== =========================================================
+``android``
``boost-`` Checks related to Boost library.
``cert-`` Checks related to CERT Secure Coding Guidelines.
``cppcoreguidelines-`` Checks related to C++ Core Guidelines.
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -4,6 +4,7 @@
=================
.. toctree::
+ android-file-open-flag
boost-use-to-string
cert-dcl03-c (redirects to misc-static-assert) <cert-dcl03-c>
cert-dcl21-cpp
Index: docs/clang-tidy/checks/android-file-open-flag.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/android-file-open-flag.rst
@@ -0,0 +1,24 @@
+.. title:: clang-tidy - android-file-open-flag
+
+android-file-open-flag
+==============================
+
+A common source of security bugs has been code that opens file without using
+the ``O_CLOEXEC`` flag. Without that flag, an opened sensitive file would
+remain open across a fork+exec to a lower-privileged SELinux domain, leaking
+that sensitive data Functions including ``open()``, ``openat()``, and
+``open64()`` must include ``O_CLOEXEC`` in their flags argument.
+
+Examples:
+
+.. code-block:: c++
+
+ open("filename", O_RDWR);
+ open64("filename", O_RDWR);
+ openat(0, "filename", O_RDWR);
+
+ // becomes
+
+ open("filename", O_RDWR | O_CLOEXEC);
+ open64("filename", O_RDWR | O_CLOEXEC);
+ openat(0, "filename", O_RDWR | O_CLOEXEC);
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -57,6 +57,12 @@
Improvements to clang-tidy
--------------------------
+- New `android-file-open-flag
+ <http://clang.llvm.org/extra/clang-tidy/checks/android-file-open-flag>`_ check
+
+ Checks if the required file flag ``O_CLOEXEC`` exists in ``open()``,
+ ``open64()`` and ``openat()``.
+
- New `cert-dcl21-cpp
<http://clang.llvm.org/extra/clang-tidy/checks/cert-dcl21-cpp.html>`_ check
Index: clang-tidy/tool/ClangTidyMain.cpp
===================================================================
--- clang-tidy/tool/ClangTidyMain.cpp
+++ clang-tidy/tool/ClangTidyMain.cpp
@@ -477,6 +477,11 @@
static int LLVM_ATTRIBUTE_UNUSED GoogleModuleAnchorDestination =
GoogleModuleAnchorSource;
+// This anchor is used to force the linker to link the AndroidModule.
+extern volatile int AndroidModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED AndroidModuleAnchorDestination =
+ AndroidModuleAnchorSource;
+
// This anchor is used to force the linker to link the MiscModule.
extern volatile int MiscModuleAnchorSource;
static int LLVM_ATTRIBUTE_UNUSED MiscModuleAnchorDestination =
Index: clang-tidy/tool/CMakeLists.txt
===================================================================
--- clang-tidy/tool/CMakeLists.txt
+++ clang-tidy/tool/CMakeLists.txt
@@ -13,6 +13,7 @@
clangASTMatchers
clangBasic
clangTidy
+ clangTidyAndroidModule
clangTidyBoostModule
clangTidyCERTModule
clangTidyCppCoreGuidelinesModule
Index: clang-tidy/plugin/CMakeLists.txt
===================================================================
--- clang-tidy/plugin/CMakeLists.txt
+++ clang-tidy/plugin/CMakeLists.txt
@@ -8,6 +8,7 @@
clangFrontend
clangSema
clangTidy
+ clangTidyAndroidModule
clangTidyBoostModule
clangTidyCERTModule
clangTidyCppCoreGuidelinesModule
Index: clang-tidy/android/FileOpenFlagCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/android/FileOpenFlagCheck.h
@@ -0,0 +1,47 @@
+//===--- FileOpenFlagCheck.h - clang-tidy----------------------------------===//
+//
+// 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_FILE_OPEN_FLAG_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_FILE_OPEN_FLAG_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Finds code that opens file without using the O_CLOEXEC flag.
+///
+/// open(), openat(), and open64() had better to include O_CLOEXEC in their
+/// flags argument. Only consider simple cases that the corresponding argument
+/// is constant or binary operation OR among constants like 'O_CLOEXEC' or
+/// 'O_CLOEXEC | O_RDONLY'. No constant propagation is performed.
+///
+/// Only the symbolic 'O_CLOEXEC' macro definition is checked, not the concrete
+/// value.
+
+class FileOpenFlagCheck : public ClangTidyCheck {
+public:
+ FileOpenFlagCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ void doCheck(const ast_matchers::MatchFinder::MatchResult &Result,
+ const CallExpr *MatchedCall, const Expr *FlagArg,
+ const FunctionDecl *FD);
+ bool checkFlags(const Expr *Flags, const SourceManager &SM);
+
+ static constexpr const char *O_CLOEXEC = "O_CLOEXEC";
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_FILE_OPEN_FLAG_H
Index: clang-tidy/android/FileOpenFlagCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/android/FileOpenFlagCheck.cpp
@@ -0,0 +1,123 @@
+//===--- FileOpenFlagCheck.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 "FileOpenFlagCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+void FileOpenFlagCheck::registerMatchers(MatchFinder *Finder) {
+ auto CharPointerType = hasType(pointerType(pointee(isAnyCharacter())));
+
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(isExternC(), returns(isInteger()),
+ hasParameter(0, CharPointerType),
+ hasParameter(1, hasType(isInteger())),
+ hasAnyName("open", "open64"))
+ .bind("funcDecl")))
+ .bind("openFn"),
+ this);
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(isExternC(), returns(isInteger()),
+ hasParameter(0, hasType(isInteger())),
+ hasParameter(1, CharPointerType),
+ hasParameter(2, hasType(isInteger())),
+ hasName("openat"))
+ .bind("funcDecl")))
+ .bind("openatFn"),
+ this);
+}
+
+void FileOpenFlagCheck::check(const MatchFinder::MatchResult &Result) {
+ const CallExpr *MatchedCall;
+ const Expr *FlagArg;
+ if ((MatchedCall = Result.Nodes.getNodeAs<CallExpr>("openFn")))
+ FlagArg = MatchedCall->getArg(1);
+ else if ((MatchedCall = Result.Nodes.getNodeAs<CallExpr>("openatFn")))
+ FlagArg = MatchedCall->getArg(2);
+ else
+ return;
+
+ const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("funcDecl");
+
+ // Check the required flag.
+ doCheck(Result, MatchedCall, FlagArg, FD);
+}
+
+void FileOpenFlagCheck::doCheck(const MatchFinder::MatchResult &Result,
+ const CallExpr *MatchedCall,
+ const Expr *FlagArg, const FunctionDecl *FD) {
+ SourceManager &SM = *Result.SourceManager;
+
+ if (!checkFlags(FlagArg->IgnoreParenCasts(), SM)) {
+ LangOptions LangOpts = getLangOpts();
+ SourceRange FlagsRange(FlagArg->getLocStart(), FlagArg->getLocEnd());
+ StringRef FlagsText = Lexer::getSourceText(
+ CharSourceRange::getTokenRange(FlagsRange), SM, LangOpts);
+ std::string ReplacementText =
+ (llvm::Twine(FlagsText) + " | " + O_CLOEXEC).str();
+ diag(FlagArg->getLocStart(), "%0 should use %1 where possible.")
+ << FD->getName() << O_CLOEXEC
+ << FixItHint::CreateReplacement(FlagsRange, ReplacementText);
+ }
+}
+
+// Check if flags contain required flag.
+// Args:
+// Flags: The argument in the code.
+// SM: The SourceManager.
+// Return:
+// True if the required flag is declared in the argument.
+bool FileOpenFlagCheck::checkFlags(const Expr *Flags, const SourceManager &SM) {
+ bool IsFlagIn;
+ // If the Flag is an integer constant, check it.
+ if (isa<IntegerLiteral>(Flags)) {
+ SourceLocation SL = Flags->getLocStart();
+
+ if (!SM.isMacroBodyExpansion(SL))
+ return false;
+
+ // Get the Marco name.
+ LangOptions LangOpts = getLangOpts();
+ auto Loc = SM.getFileLoc(SL);
+ std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(Loc);
+ unsigned MacroTokenLength = Lexer::MeasureTokenLength(Loc, SM, LangOpts);
+ StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
+ auto MacroName =
+ ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
+
+ IsFlagIn = (MacroName == O_CLOEXEC);
+
+ }
+ // If it's a binary OR operation.
+ else if ((isa<BinaryOperator>(Flags)) &&
+ (cast<BinaryOperator>(Flags)->getOpcode() ==
+ clang::BinaryOperatorKind::BO_Or)) {
+ IsFlagIn =
+ checkFlags(cast<BinaryOperator>(Flags)->getLHS()->IgnoreParenCasts(),
+ SM) ||
+ checkFlags(cast<BinaryOperator>(Flags)->getRHS()->IgnoreParenCasts(),
+ SM);
+ }
+ // Otherwise, we assume it has the flag to avoid false positive.
+ else
+ IsFlagIn = true;
+
+ return IsFlagIn;
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/android/CMakeLists.txt
===================================================================
--- /dev/null
+++ clang-tidy/android/CMakeLists.txt
@@ -0,0 +1,14 @@
+set(LLVM_LINK_COMPONENTS support)
+
+add_clang_library(clangTidyAndroidModule
+ AndroidTidyModule.cpp
+ FileOpenFlagCheck.cpp
+
+ LINK_LIBS
+ clangAST
+ clangASTMatchers
+ clangBasic
+ clangLex
+ clangTidy
+ clangTidyUtils
+ )
Index: clang-tidy/android/AndroidTidyModule.cpp
===================================================================
--- /dev/null
+++ clang-tidy/android/AndroidTidyModule.cpp
@@ -0,0 +1,41 @@
+//===--- 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 "FileOpenFlagCheck.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<FileOpenFlagCheck>("android-file-open-flag");
+ }
+};
+
+// Register the AndroidTidyModule using this statically initialized variable.
+static ClangTidyModuleRegistry::Add<AndroidModule>
+ X("android-module", "Adds Android platform checks.");
+
+} // namespace android
+
+// This anchor is used to force the linker to link in the generated object file
+// and thus register the AndroidModule.
+volatile int AndroidModuleAnchorSource = 0;
+
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/CMakeLists.txt
===================================================================
--- clang-tidy/CMakeLists.txt
+++ clang-tidy/CMakeLists.txt
@@ -26,6 +26,7 @@
clangToolingCore
)
+add_subdirectory(android)
add_subdirectory(boost)
add_subdirectory(cert)
add_subdirectory(cppcoreguidelines)
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