Author: Alex Lorenz Date: 2022-02-02T11:16:11-08:00 New Revision: 979d0ee8ab30a175220af3b39a6df7d56de9d2c8
URL: https://github.com/llvm/llvm-project/commit/979d0ee8ab30a175220af3b39a6df7d56de9d2c8 DIFF: https://github.com/llvm/llvm-project/commit/979d0ee8ab30a175220af3b39a6df7d56de9d2c8.diff LOG: [clang] fix out of bounds access in an empty string when lexing a _Pragma with missing string token The lexer can attempt to lex a _Pragma and crash with an out of bounds string access when it's lexing a _Pragma whose string token is an invalid buffer, e.g. when a module header file from which the macro expansion for that token was deleted from the file system. Differential Revision: https://reviews.llvm.org/D116052 Added: clang/test/Preprocessor/pragma-missing-string-token.c Modified: clang/lib/Frontend/PrintPreprocessedOutput.cpp clang/lib/Lex/Pragma.cpp Removed: ################################################################################ diff --git a/clang/lib/Frontend/PrintPreprocessedOutput.cpp b/clang/lib/Frontend/PrintPreprocessedOutput.cpp index 1d0022bda474c..e2fc862849ad1 100644 --- a/clang/lib/Frontend/PrintPreprocessedOutput.cpp +++ b/clang/lib/Frontend/PrintPreprocessedOutput.cpp @@ -189,7 +189,8 @@ class PrintPPOutputPPCallbacks : public PPCallbacks { bool MoveToLine(const Token &Tok, bool RequireStartOfLine) { PresumedLoc PLoc = SM.getPresumedLoc(Tok.getLocation()); unsigned TargetLine = PLoc.isValid() ? PLoc.getLine() : CurLine; - bool IsFirstInFile = Tok.isAtStartOfLine() && PLoc.getLine() == 1; + bool IsFirstInFile = + Tok.isAtStartOfLine() && PLoc.isValid() && PLoc.getLine() == 1; return MoveToLine(TargetLine, RequireStartOfLine) || IsFirstInFile; } diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp index eb7e7cbc47140..eb370e8a0ecd6 100644 --- a/clang/lib/Lex/Pragma.cpp +++ b/clang/lib/Lex/Pragma.cpp @@ -263,7 +263,12 @@ void Preprocessor::Handle_Pragma(Token &Tok) { } SourceLocation RParenLoc = Tok.getLocation(); - std::string StrVal = getSpelling(StrTok); + bool Invalid = false; + std::string StrVal = getSpelling(StrTok, &Invalid); + if (Invalid) { + Diag(PragmaLoc, diag::err__Pragma_malformed); + return; + } // The _Pragma is lexically sound. Destringize according to C11 6.10.9.1: // "The string literal is destringized by deleting any encoding prefix, diff --git a/clang/test/Preprocessor/pragma-missing-string-token.c b/clang/test/Preprocessor/pragma-missing-string-token.c new file mode 100644 index 0000000000000..5f40b2f4fdb97 --- /dev/null +++ b/clang/test/Preprocessor/pragma-missing-string-token.c @@ -0,0 +1,27 @@ +// RUN: rm -rf %t +// RUN: split-file %s %t + +// RUN: %clang_cc1 -emit-module -x c -fmodules -I %t/Inputs -fmodule-name=aa %t/Inputs/module.modulemap -o %t/aa.pcm +// RUN: rm %t/Inputs/b.h +// RUN: not %clang_cc1 -E -fmodules -I %t/Inputs -fmodule-file=%t/aa.pcm %s -o - -fallow-pcm-with-compiler-errors 2>&1 | FileCheck %s + +//--- Inputs/module.modulemap +module aa { + header "a.h" + header "b.h" +} + +//--- Inputs/a.h +#define TEST(x) x + +//--- Inputs/b.h +#define SUB "mypragma" + +//--- test.c +#include "a.h" + +_Pragma(SUB); +int a = TEST(SUB); + +// CHECK: int a +// CHECK: 1 error generated _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
