From 5965fbf81b25217c40b09b48bd808a8f4a5d4e89 Mon Sep 17 00:00:00 2001 From: Aleksandr Platonov Date: Mon, 10 Aug 2020 10:23:08 +0300 Subject: [PATCH] [clang-tidy] Fix a crash in bugprone-not-null-terminated-result check when `__STDC_WANT_LIB_EXT1__` was undefined after definition. PP->getMacroInfo() returns nullptr for undefined macro, so we need to check this return value before dereference. Stack dump: ``` #0 0x0000000002185e6a llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/llvm-project/build/bin/clang-tidy+0x2185e6a) #1 0x0000000002183e8c llvm::sys::RunSignalHandlers() (/llvm-project/build/bin/clang-tidy+0x2183e8c) #2 0x0000000002183ff3 SignalHandler(int) (/llvm-project/build/bin/clang-tidy+0x2183ff3) #3 0x00007f37df9b1390 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390) #4 0x000000000052054e clang::tidy::bugprone::NotNullTerminatedResultCheck::check(clang::ast_matchers::MatchFinder::MatchResult const&) (/llvm-project/build/bin/clang-tidy+0x52054e) ``` Reviewed By: hokein Differential Revision: https://reviews.llvm.org/D85523 --- .../bugprone/NotNullTerminatedResultCheck.cpp | 13 ++++++++----- ...terminated-result-undef-stdc-want-lib-ext1.c | 17 +++++++++++++++++ 2 files changed, 25 insertions(+), 5 deletions(-) create mode 100644 clang-tools-extra/test/clang-tidy/checkers/bugprone-not-null-terminated-result-undef-stdc-want-lib-ext1.c diff --git a/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp index 269d69c1c124..7d484d777165 100644 --- a/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp +++ b/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp @@ -802,11 +802,14 @@ void NotNullTerminatedResultCheck::check( while (It != PP->macro_end() && !AreSafeFunctionsWanted.hasValue()) { if (It->first->getName() == "__STDC_WANT_LIB_EXT1__") { const auto *MI = PP->getMacroInfo(It->first); - const auto &T = MI->tokens().back(); - StringRef ValueStr = StringRef(T.getLiteralData(), T.getLength()); - llvm::APInt IntValue; - ValueStr.getAsInteger(10, IntValue); - AreSafeFunctionsWanted = IntValue.getZExtValue(); + // PP->getMacroInfo() returns nullptr if macro has no definition. + if (MI) { + const auto &T = MI->tokens().back(); + StringRef ValueStr = StringRef(T.getLiteralData(), T.getLength()); + llvm::APInt IntValue; + ValueStr.getAsInteger(10, IntValue); + AreSafeFunctionsWanted = IntValue.getZExtValue(); + } } ++It; diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-not-null-terminated-result-undef-stdc-want-lib-ext1.c b/clang-tools-extra/test/clang-tidy/checkers/bugprone-not-null-terminated-result-undef-stdc-want-lib-ext1.c new file mode 100644 index 000000000000..25e38800d28b --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-not-null-terminated-result-undef-stdc-want-lib-ext1.c @@ -0,0 +1,17 @@ +// RUN: %check_clang_tidy %s bugprone-not-null-terminated-result %t -- \ +// RUN: -- -std=c11 -I %S/Inputs/bugprone-not-null-terminated-result + +#include "not-null-terminated-result-c.h" + +#define __STDC_LIB_EXT1__ 1 +#define __STDC_WANT_LIB_EXT1__ 1 +#undef __STDC_WANT_LIB_EXT1__ + +void f(const char *src) { + char dest[13]; + memcpy_s(dest, 13, src, strlen(src) - 1); + // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: the result from calling 'memcpy_s' is not null-terminated [bugprone-not-null-terminated-result] + // CHECK-FIXES: char dest[14]; + // CHECK-FIXES-NEXT: strncpy_s(dest, 14, src, strlen(src) - 1); +} +