341 lines
13 KiB
Diff
341 lines
13 KiB
Diff
From e7ab823a5f3f57e843069d43033a16165809723a Mon Sep 17 00:00:00 2001
|
||
From: serge-sans-paille <sguelton@redhat.com>
|
||
Date: Thu, 4 Nov 2021 11:11:53 +0100
|
||
Subject: [PATCH 2/3] Misleading bidirectional detection
|
||
|
||
Differential Revision: https://reviews.llvm.org/D112913
|
||
---
|
||
clang-tools-extra/clang-tidy/misc/CMakeLists.txt | 1 +
|
||
.../clang-tidy/misc/MiscTidyModule.cpp | 3 +
|
||
.../clang-tidy/misc/MisleadingBidirectional.cpp | 131 +++++++++++++++++++++
|
||
.../clang-tidy/misc/MisleadingBidirectional.h | 38 ++++++
|
||
clang-tools-extra/docs/ReleaseNotes.rst | 5 +
|
||
clang-tools-extra/docs/clang-tidy/checks/list.rst | 3 +-
|
||
.../checks/misc-misleading-bidirectional.rst | 21 ++++
|
||
.../checkers/misc-misleading-bidirectional.cpp | 31 +++++
|
||
8 files changed, 232 insertions(+), 1 deletion(-)
|
||
create mode 100644 clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.cpp
|
||
create mode 100644 clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.h
|
||
create mode 100644 clang-tools-extra/docs/clang-tidy/checks/misc-misleading-bidirectional.rst
|
||
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/misc-misleading-bidirectional.cpp
|
||
|
||
diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
|
||
index 7cafe54..e6abac8 100644
|
||
--- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
|
||
+++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
|
||
@@ -16,6 +16,7 @@ add_clang_library(clangTidyMiscModule
|
||
DefinitionsInHeadersCheck.cpp
|
||
Homoglyph.cpp
|
||
MiscTidyModule.cpp
|
||
+ MisleadingBidirectional.cpp
|
||
MisplacedConstCheck.cpp
|
||
NewDeleteOverloadsCheck.cpp
|
||
NoRecursionCheck.cpp
|
||
diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
|
||
index 5c7bd0c..bb5fde2 100644
|
||
--- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
|
||
+++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
|
||
@@ -11,6 +11,7 @@
|
||
#include "../ClangTidyModuleRegistry.h"
|
||
#include "DefinitionsInHeadersCheck.h"
|
||
#include "Homoglyph.h"
|
||
+#include "MisleadingBidirectional.h"
|
||
#include "MisplacedConstCheck.h"
|
||
#include "NewDeleteOverloadsCheck.h"
|
||
#include "NoRecursionCheck.h"
|
||
@@ -35,6 +36,8 @@ public:
|
||
CheckFactories.registerCheck<DefinitionsInHeadersCheck>(
|
||
"misc-definitions-in-headers");
|
||
CheckFactories.registerCheck<Homoglyph>("misc-homoglyph");
|
||
+ CheckFactories.registerCheck<MisleadingBidirectionalCheck>(
|
||
+ "misc-misleading-bidirectional");
|
||
CheckFactories.registerCheck<MisplacedConstCheck>("misc-misplaced-const");
|
||
CheckFactories.registerCheck<NewDeleteOverloadsCheck>(
|
||
"misc-new-delete-overloads");
|
||
diff --git a/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.cpp b/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.cpp
|
||
new file mode 100644
|
||
index 0000000..7a2f06b
|
||
--- /dev/null
|
||
+++ b/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.cpp
|
||
@@ -0,0 +1,139 @@
|
||
+//===--- MisleadingBidirectional.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 "MisleadingBidirectional.h"
|
||
+
|
||
+#include "clang/Frontend/CompilerInstance.h"
|
||
+#include "clang/Lex/Preprocessor.h"
|
||
+#include "llvm/Support/ConvertUTF.h"
|
||
+
|
||
+using namespace clang;
|
||
+using namespace clang::tidy::misc;
|
||
+
|
||
+static bool containsMisleadingBidi(StringRef Buffer,
|
||
+ bool HonorLineBreaks = true) {
|
||
+ const char *CurPtr = Buffer.begin();
|
||
+
|
||
+ enum BidiChar {
|
||
+ PS = 0x2029,
|
||
+ RLO = 0x202E,
|
||
+ RLE = 0x202B,
|
||
+ LRO = 0x202D,
|
||
+ LRE = 0x202A,
|
||
+ PDF = 0x202C,
|
||
+ RLI = 0x2067,
|
||
+ LRI = 0x2066,
|
||
+ FSI = 0x2068,
|
||
+ PDI = 0x2069
|
||
+ };
|
||
+
|
||
+ SmallVector<BidiChar> BidiContexts;
|
||
+
|
||
+ // Scan each character while maintaining a stack of opened bidi context.
|
||
+ // RLO/RLE/LRO/LRE all are closed by PDF while RLI LRI and FSI are closed by
|
||
+ // PDI. New lines reset the context count. Extra PDF / PDI are ignored.
|
||
+ //
|
||
+ // Warn if we end up with an unclosed context.
|
||
+ while (CurPtr < Buffer.end()) {
|
||
+ unsigned char C = *CurPtr;
|
||
+ if (isASCII(C)) {
|
||
+ ++CurPtr;
|
||
+ bool IsParagrapSep =
|
||
+ (C == 0xA || C == 0xD || (0x1C <= C && C <= 0x1E) || C == 0x85);
|
||
+ bool IsSegmentSep = (C == 0x9 || C == 0xB || C == 0x1F);
|
||
+ if (IsParagrapSep || IsSegmentSep)
|
||
+ BidiContexts.clear();
|
||
+ continue;
|
||
+ }
|
||
+ llvm::UTF32 CodePoint;
|
||
+ llvm::ConversionResult Result = llvm::convertUTF8Sequence(
|
||
+ (const llvm::UTF8 **)&CurPtr, (const llvm::UTF8 *)Buffer.end(),
|
||
+ &CodePoint, llvm::strictConversion);
|
||
+
|
||
+ // If conversion fails, utf-8 is designed so that we can just try next char.
|
||
+ if (Result != llvm::conversionOK) {
|
||
+ ++CurPtr;
|
||
+ continue;
|
||
+ }
|
||
+
|
||
+ // Open a PDF context.
|
||
+ if (CodePoint == RLO || CodePoint == RLE || CodePoint == LRO ||
|
||
+ CodePoint == LRE)
|
||
+ BidiContexts.push_back(PDF);
|
||
+ // Close PDF Context.
|
||
+ else if (CodePoint == PDF) {
|
||
+ if (!BidiContexts.empty() && BidiContexts.back() == PDF)
|
||
+ BidiContexts.pop_back();
|
||
+ }
|
||
+ // Open a PDI Context.
|
||
+ else if (CodePoint == RLI || CodePoint == LRI || CodePoint == FSI)
|
||
+ BidiContexts.push_back(PDI);
|
||
+ // Close a PDI Context.
|
||
+ else if (CodePoint == PDI) {
|
||
+ auto R = std::find(BidiContexts.rbegin(), BidiContexts.rend(), PDI);
|
||
+ if (R != BidiContexts.rend())
|
||
+ BidiContexts.resize(BidiContexts.rend() - R - 1);
|
||
+ }
|
||
+ // Line break or equivalent
|
||
+ else if (CodePoint == PS)
|
||
+ BidiContexts.clear();
|
||
+ }
|
||
+ return !BidiContexts.empty();
|
||
+}
|
||
+
|
||
+class MisleadingBidirectionalCheck::MisleadingBidirectionalHandler
|
||
+ : public CommentHandler {
|
||
+public:
|
||
+ MisleadingBidirectionalHandler(MisleadingBidirectionalCheck &Check,
|
||
+ llvm::Optional<std::string> User)
|
||
+ : Check(Check) {}
|
||
+
|
||
+ bool HandleComment(Preprocessor &PP, SourceRange Range) override {
|
||
+ // FIXME: check that we are in a /* */ comment
|
||
+ StringRef Text =
|
||
+ Lexer::getSourceText(CharSourceRange::getCharRange(Range),
|
||
+ PP.getSourceManager(), PP.getLangOpts());
|
||
+
|
||
+ if (containsMisleadingBidi(Text, true))
|
||
+ Check.diag(
|
||
+ Range.getBegin(),
|
||
+ "comment contains misleading bidirectional Unicode characters");
|
||
+ return false;
|
||
+ }
|
||
+
|
||
+private:
|
||
+ MisleadingBidirectionalCheck &Check;
|
||
+};
|
||
+
|
||
+MisleadingBidirectionalCheck::MisleadingBidirectionalCheck(
|
||
+ StringRef Name, ClangTidyContext *Context)
|
||
+ : ClangTidyCheck(Name, Context),
|
||
+ Handler(std::make_unique<MisleadingBidirectionalHandler>(
|
||
+ *this, Context->getOptions().User)) {}
|
||
+
|
||
+MisleadingBidirectionalCheck::~MisleadingBidirectionalCheck() = default;
|
||
+
|
||
+void MisleadingBidirectionalCheck::registerPPCallbacks(
|
||
+ const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
|
||
+ PP->addCommentHandler(Handler.get());
|
||
+}
|
||
+
|
||
+void MisleadingBidirectionalCheck::check(
|
||
+ const ast_matchers::MatchFinder::MatchResult &Result) {
|
||
+ if (const auto *SL = Result.Nodes.getNodeAs<StringLiteral>("strlit")) {
|
||
+ StringRef Literal = SL->getBytes();
|
||
+ if (containsMisleadingBidi(Literal, false))
|
||
+ diag(SL->getBeginLoc(), "string literal contains misleading "
|
||
+ "bidirectional Unicode characters");
|
||
+ }
|
||
+}
|
||
+
|
||
+void MisleadingBidirectionalCheck::registerMatchers(
|
||
+ ast_matchers::MatchFinder *Finder) {
|
||
+ Finder->addMatcher(ast_matchers::stringLiteral().bind("strlit"), this);
|
||
+}
|
||
diff --git a/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.h b/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.h
|
||
new file mode 100644
|
||
index 0000000..18e7060
|
||
--- /dev/null
|
||
+++ b/clang-tools-extra/clang-tidy/misc/MisleadingBidirectional.h
|
||
@@ -0,0 +1,38 @@
|
||
+//===--- MisleadingBidirectionalCheck.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_MISC_MISLEADINGBIDIRECTIONALCHECK_H
|
||
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MISLEADINGBIDIRECTIONALCHECK_H
|
||
+
|
||
+#include "../ClangTidyCheck.h"
|
||
+
|
||
+namespace clang {
|
||
+namespace tidy {
|
||
+namespace misc {
|
||
+
|
||
+class MisleadingBidirectionalCheck : public ClangTidyCheck {
|
||
+public:
|
||
+ MisleadingBidirectionalCheck(StringRef Name, ClangTidyContext *Context);
|
||
+ ~MisleadingBidirectionalCheck();
|
||
+
|
||
+ void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
|
||
+ Preprocessor *ModuleExpanderPP) override;
|
||
+
|
||
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
|
||
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
|
||
+
|
||
+private:
|
||
+ class MisleadingBidirectionalHandler;
|
||
+ std::unique_ptr<MisleadingBidirectionalHandler> Handler;
|
||
+};
|
||
+
|
||
+} // namespace misc
|
||
+} // namespace tidy
|
||
+} // namespace clang
|
||
+
|
||
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MISLEADINGBIDIRECTIONALCHECK_H
|
||
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
|
||
index 37a717e..1eec7db 100644
|
||
--- a/clang-tools-extra/docs/ReleaseNotes.rst
|
||
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
|
||
@@ -218,6 +218,11 @@ New checks
|
||
|
||
Detects confusable unicode identifiers.
|
||
|
||
+- New :doc:`misc-misleading-bidirectional <clang-tidy/checks/misc-misleading-bidirectional>` check.
|
||
+
|
||
+ Inspect string literal and comments for unterminated bidirectional Unicode
|
||
+ characters.
|
||
+
|
||
New check aliases
|
||
^^^^^^^^^^^^^^^^^
|
||
|
||
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
|
||
index df9a95c..b118639 100644
|
||
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
|
||
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
|
||
@@ -207,7 +207,8 @@ Clang-Tidy Checks
|
||
`llvmlibc-implementation-in-namespace <llvmlibc-implementation-in-namespace.html>`_,
|
||
`llvmlibc-restrict-system-libc-headers <llvmlibc-restrict-system-libc-headers.html>`_, "Yes"
|
||
`misc-definitions-in-headers <misc-definitions-in-headers.html>`_, "Yes"
|
||
- `misc-homoglyph <misc-homoglyph.html>`_, "Yes"
|
||
+ `misc-homoglyph <misc-homoglyph.html>`_,
|
||
+ `misc-misleading-bidirectional <misc-misleading-bidirectional.html>`_,
|
||
`misc-misplaced-const <misc-misplaced-const.html>`_,
|
||
`misc-new-delete-overloads <misc-new-delete-overloads.html>`_,
|
||
`misc-no-recursion <misc-no-recursion.html>`_,
|
||
diff --git a/clang-tools-extra/docs/clang-tidy/checks/misc-misleading-bidirectional.rst b/clang-tools-extra/docs/clang-tidy/checks/misc-misleading-bidirectional.rst
|
||
new file mode 100644
|
||
index 0000000..16ffc97
|
||
--- /dev/null
|
||
+++ b/clang-tools-extra/docs/clang-tidy/checks/misc-misleading-bidirectional.rst
|
||
@@ -0,0 +1,21 @@
|
||
+.. title:: clang-tidy - misc-misleading-bidirectional
|
||
+
|
||
+misc-misleading-bidirectional
|
||
+=============================
|
||
+
|
||
+Warn about unterminated bidirectional unicode sequence, detecting potential attack
|
||
+as described in the `Trojan Source <https://www.trojansource.codes>`_ attack.
|
||
+
|
||
+Example:
|
||
+
|
||
+.. code-block:: c++
|
||
+
|
||
+ #include <iostream>
|
||
+
|
||
+ int main() {
|
||
+ bool isAdmin = false;
|
||
+ /* } if (isAdmin) begin admins only */
|
||
+ std::cout << "You are an admin.\n";
|
||
+ /* end admins only { */
|
||
+ return 0;
|
||
+ }
|
||
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc-misleading-bidirectional.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc-misleading-bidirectional.cpp
|
||
new file mode 100644
|
||
index 0000000..7a1746d
|
||
--- /dev/null
|
||
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc-misleading-bidirectional.cpp
|
||
@@ -0,0 +1,31 @@
|
||
+// RUN: %check_clang_tidy %s misc-misleading-bidirectional %t
|
||
+
|
||
+void func(void) {
|
||
+ int admin = 0;
|
||
+ /* }if(admin) begin*/
|
||
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comment contains misleading bidirectional Unicode characters [misc-misleading-bidirectional]
|
||
+ const char msg[] = "if(admin) tes";
|
||
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: string literal contains misleading bidirectional Unicode characters [misc-misleading-bidirectional]
|
||
+}
|
||
+
|
||
+void all_fine(void) {
|
||
+ char valid[] = "somevalidsequence";
|
||
+ /* EOL ends bidi sequence
|
||
+ * end it's fine to do so.
|
||
+ * EOL ends isolate too
|
||
+ */
|
||
+}
|
||
+
|
||
+int invalid_utf_8(void) {
|
||
+ bool isAdmin = false;
|
||
+
|
||
+ // the comment below contains an invalid utf8 character, but should still be
|
||
+ // processed.
|
||
+
|
||
+ // CHECK-MESSAGES: :[[@LINE+1]]:3: warning: comment contains misleading bidirectional Unicode characters [misc-misleading-bidirectional]
|
||
+ /* } if (isAdmin) begin admins only */
|
||
+ return 1;
|
||
+ /* end admins only { */
|
||
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comment contains misleading bidirectional Unicode characters [misc-misleading-bidirectional]
|
||
+ return 0;
|
||
+}
|
||
--
|
||
1.8.3.1
|
||
|