Author: yawanng Date: Thu Aug 10 10:18:10 2017 New Revision: 310630 URL: http://llvm.org/viewvc/llvm-project?rev=310630&view=rev Log: [clang-tidy] Refactor the code and add a close-on-exec check on memfd_create() in Android module.
Summary: 1. Refactor the structure of the code by adding a base class for all close-on-exec checks, which implements most of the needed functions. 2. memfd_create() is better to set MFD_CLOEXEC flag to avoid file descriptor leakage. Reviewers: alexfh, aaron.ballman, hokein Reviewed By: alexfh, hokein Subscribers: Eugene.Zelenko, chh, cfe-commits, srhines, mgorny, JDevlieghere, xazax.hun Tags: #clang-tools-extra Differential Revision: https://reviews.llvm.org/D35372 Added: clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.cpp clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.h clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.cpp clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.h clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-memfd-create.rst clang-tools-extra/trunk/test/clang-tidy/android-cloexec-memfd-create.cpp Modified: clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt clang-tools-extra/trunk/docs/ReleaseNotes.rst clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Modified: clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp?rev=310630&r1=310629&r2=310630&view=diff ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp (original) +++ clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp Thu Aug 10 10:18:10 2017 @@ -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 @@ public: 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"); } Modified: clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt?rev=310630&r1=310629&r2=310630&view=diff ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt (original) +++ clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt Thu Aug 10 10:18:10 2017 @@ -2,8 +2,10 @@ set(LLVM_LINK_COMPONENTS support) add_clang_library(clangTidyAndroidModule AndroidTidyModule.cpp + CloexecCheck.cpp CloexecCreatCheck.cpp CloexecFopenCheck.cpp + CloexecMemfdCreateCheck.cpp CloexecOpenCheck.cpp CloexecSocketCheck.cpp Added: clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.cpp URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.cpp?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.cpp (added) +++ clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.cpp Thu Aug 10 10:18:10 2017 @@ -0,0 +1,105 @@ +//===--- CloexecCheck.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 "CloexecCheck.h" +#include "../utils/ASTUtils.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 { + +namespace { + +const char *const FuncDeclBindingStr = "funcDecl"; +const char *const FuncBindingStr = "func"; + +// Helper function to form the correct string mode for Type3. +// Build the replace text. If it's string constant, add <Mode> directly in the +// end of the string. Else, add <Mode>. +std::string buildFixMsgForStringFlag(const Expr *Arg, const SourceManager &SM, + const LangOptions &LangOpts, char Mode) { + if (Arg->getLocStart().isMacroID()) + return (Lexer::getSourceText( + CharSourceRange::getTokenRange(Arg->getSourceRange()), SM, + LangOpts) + + " \"" + Twine(Mode) + "\"") + .str(); + + StringRef SR = cast<StringLiteral>(Arg->IgnoreParenCasts())->getString(); + return ("\"" + SR + Twine(Mode) + "\"").str(); +} +} // namespace + +void CloexecCheck::registerMatchersImpl( + MatchFinder *Finder, internal::Matcher<FunctionDecl> Function) { + // We assume all the checked APIs are C functions. + Finder->addMatcher( + callExpr( + callee(functionDecl(isExternC(), Function).bind(FuncDeclBindingStr))) + .bind(FuncBindingStr), + this); +} + +void CloexecCheck::insertMacroFlag(const MatchFinder::MatchResult &Result, + StringRef MacroFlag, int ArgPos) { + const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr); + const auto *FlagArg = MatchedCall->getArg(ArgPos); + const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>(FuncDeclBindingStr); + SourceManager &SM = *Result.SourceManager; + + if (utils::exprHasBitFlagWithSpelling(FlagArg->IgnoreParenCasts(), SM, + Result.Context->getLangOpts(), + MacroFlag)) + return; + + SourceLocation EndLoc = + Lexer::getLocForEndOfToken(SM.getFileLoc(FlagArg->getLocEnd()), 0, SM, + Result.Context->getLangOpts()); + + diag(EndLoc, "%0 should use %1 where possible") + << FD << MacroFlag + << FixItHint::CreateInsertion(EndLoc, (Twine(" | ") + MacroFlag).str()); +} + +void CloexecCheck::replaceFunc(const MatchFinder::MatchResult &Result, + StringRef WarningMsg, StringRef FixMsg) { + const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr); + diag(MatchedCall->getLocStart(), WarningMsg) + << FixItHint::CreateReplacement(MatchedCall->getSourceRange(), FixMsg); +} + +void CloexecCheck::insertStringFlag( + const ast_matchers::MatchFinder::MatchResult &Result, const char Mode, + const int ArgPos) { + const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr); + const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>(FuncDeclBindingStr); + const auto *ModeArg = MatchedCall->getArg(ArgPos); + + // Check if the <Mode> may be in the mode string. + const auto *ModeStr = dyn_cast<StringLiteral>(ModeArg->IgnoreParenCasts()); + if (!ModeStr || (ModeStr->getString().find(Mode) != StringRef::npos)) + return; + + const std::string &ReplacementText = buildFixMsgForStringFlag( + ModeArg, *Result.SourceManager, Result.Context->getLangOpts(), Mode); + + diag(ModeArg->getLocStart(), "use %0 mode '%1' to set O_CLOEXEC") + << FD << Mode + << FixItHint::CreateReplacement(ModeArg->getSourceRange(), + ReplacementText); +} + +} // namespace android +} // namespace tidy +} // namespace clang Added: clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.h URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.h?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.h (added) +++ clang-tools-extra/trunk/clang-tidy/android/CloexecCheck.h Thu Aug 10 10:18:10 2017 @@ -0,0 +1,95 @@ +//===--- CloexecCheck.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. +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// This file contains the declaration of the CloexecCheck class, which is the +/// base class for all of the close-on-exec checks in Android module. +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { +namespace android { + +/// \brief The base class for all close-on-exec checks in Android module. +/// To be specific, there are some functions that need the close-on-exec flag to +/// prevent the file descriptor leakage on fork+exec and this class provides +/// utilities to identify and fix these C functions. +class CloexecCheck : public ClangTidyCheck { +public: + CloexecCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + +protected: + void + registerMatchersImpl(ast_matchers::MatchFinder *Finder, + ast_matchers::internal::Matcher<FunctionDecl> Function); + + /// Currently, we have three types of fixes. + /// + /// Type1 is to insert the necessary macro flag in the flag argument. For + /// example, 'O_CLOEXEC' is required in function 'open()', so + /// \code + /// open(file, O_RDONLY); + /// \endcode + /// should be + /// \code + /// open(file, O_RDONLY | O_CLOEXE); + /// \endcode + /// + /// \param [out] Result MatchResult from AST matcher. + /// \param MacroFlag The macro name of the flag. + /// \param ArgPos The 0-based position of the flag argument. + void insertMacroFlag(const ast_matchers::MatchFinder::MatchResult &Result, + StringRef MarcoFlag, int ArgPos); + + /// Type2 is to replace the API to another function that has required the + /// ability. For example: + /// \code + /// creat(path, mode); + /// \endcode + /// should be + /// \code + /// open(path, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, mode) + /// \endcode + /// + /// \param [out] Result MatchResult from AST matcher. + /// \param WarningMsg The warning message. + /// \param FixMsg The fix message. + void replaceFunc(const ast_matchers::MatchFinder::MatchResult &Result, + StringRef WarningMsg, StringRef FixMsg); + + /// Type3 is also to add a flag to the corresponding argument, but this time, + /// the flag is some string and each char represents a mode rather than a + /// macro. For example, 'fopen' needs char 'e' in its mode argument string, so + /// \code + /// fopen(in_file, "r"); + /// \endcode + /// should be + /// \code + /// fopen(in_file, "re"); + /// \endcode + /// + /// \param [out] Result MatchResult from AST matcher. + /// \param Mode The required mode char. + /// \param ArgPos The 0-based position of the flag argument. + void insertStringFlag(const ast_matchers::MatchFinder::MatchResult &Result, + char Mode, const int ArgPos); +}; + +} // namespace android +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H Added: clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.cpp URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.cpp?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.cpp (added) +++ clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.cpp Thu Aug 10 10:18:10 2017 @@ -0,0 +1,32 @@ +//===--- 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" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace android { + +void CloexecMemfdCreateCheck::registerMatchers(MatchFinder *Finder) { + auto CharPointerType = hasType(pointerType(pointee(isAnyCharacter()))); + registerMatchersImpl( + Finder, functionDecl(returns(isInteger()), hasName("memfd_create"), + hasParameter(0, CharPointerType), + hasParameter(1, hasType(isInteger())))); +} + +void CloexecMemfdCreateCheck::check(const MatchFinder::MatchResult &Result) { + insertMacroFlag(Result, "MFD_CLOEXEC", /*ArgPos=*/1); +} + +} // namespace android +} // namespace tidy +} // namespace clang Added: clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.h URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.h?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.h (added) +++ clang-tools-extra/trunk/clang-tidy/android/CloexecMemfdCreateCheck.h Thu Aug 10 10:18:10 2017 @@ -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 "CloexecCheck.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 CloexecCheck { +public: + CloexecMemfdCreateCheck(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_MEMFD_CREATE_H Modified: clang-tools-extra/trunk/docs/ReleaseNotes.rst URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/ReleaseNotes.rst?rev=310630&r1=310629&r2=310630&view=diff ============================================================================== --- clang-tools-extra/trunk/docs/ReleaseNotes.rst (original) +++ clang-tools-extra/trunk/docs/ReleaseNotes.rst Thu Aug 10 10:18:10 2017 @@ -70,6 +70,12 @@ Improvements to clang-tidy ``AllowConditionalIntegerCasts`` -> ``AllowIntegerConditions``, ``AllowConditionalPointerCasts`` -> ``AllowPointerConditions``. +- 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 `bugprone-integer-division <http://clang.llvm.org/extra/clang-tidy/checks/bugprone-integer-division.html>`_ check Added: clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-memfd-create.rst URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-memfd-create.rst?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-memfd-create.rst (added) +++ clang-tools-extra/trunk/docs/clang-tidy/checks/android-cloexec-memfd-create.rst Thu Aug 10 10:18:10 2017 @@ -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); Modified: clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst?rev=310630&r1=310629&r2=310630&view=diff ============================================================================== --- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst (original) +++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Thu Aug 10 10:18:10 2017 @@ -6,6 +6,7 @@ Clang-Tidy Checks .. toctree:: android-cloexec-creat android-cloexec-fopen + android-cloexec-memfd-create android-cloexec-open android-cloexec-socket boost-use-to-string Added: clang-tools-extra/trunk/test/clang-tidy/android-cloexec-memfd-create.cpp URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/android-cloexec-memfd-create.cpp?rev=310630&view=auto ============================================================================== --- clang-tools-extra/trunk/test/clang-tidy/android-cloexec-memfd-create.cpp (added) +++ clang-tools-extra/trunk/test/clang-tidy/android-cloexec-memfd-create.cpp Thu Aug 10 10:18:10 2017 @@ -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)); + } +}; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
