From d44be968938ecf95023351a358c43c4957638d87 Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Fri, 5 Feb 2021 19:44:26 +0100 Subject: [PATCH] Kernel: KUBSAN! (Kernel Undefined Behavior SANitizer) :^) We now build the kernel with partial UBSAN support. The following -fsanitize sub-options are enabled: * nonnull-attribute * bool If the kernel detects UB at runtime, it will now print a debug message with a stack trace. This is very cool! I'm leaving it on by default for now, but we'll probably have to re-evaluate this as more options are enabled and slowdown increases. --- Kernel/CMakeLists.txt | 2 ++ Kernel/UBSanitizer.cpp | 56 ++++++++++++++++++++++++++++++ Kernel/UBSanitizer.h | 77 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 135 insertions(+) create mode 100644 Kernel/UBSanitizer.cpp create mode 100644 Kernel/UBSanitizer.h diff --git a/Kernel/CMakeLists.txt b/Kernel/CMakeLists.txt index ec0d2840cb..0351c09c28 100644 --- a/Kernel/CMakeLists.txt +++ b/Kernel/CMakeLists.txt @@ -197,6 +197,7 @@ set(KERNEL_SOURCES Time/RTC.cpp Time/TimeManagement.cpp TimerQueue.cpp + UBSanitizer.cpp UserOrKernelBuffer.cpp VM/AnonymousVMObject.cpp VM/ContiguousVMObject.cpp @@ -269,6 +270,7 @@ set(SOURCES ${C_SOURCES} ) +set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=nonnull-attribute,bool") set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unknown-warning-option -DKERNEL") set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pie -fPIE -fno-rtti -ffreestanding -fbuiltin") set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mno-80387 -mno-mmx -mno-sse -mno-sse2") diff --git a/Kernel/UBSanitizer.cpp b/Kernel/UBSanitizer.cpp new file mode 100644 index 0000000000..454a8e5c79 --- /dev/null +++ b/Kernel/UBSanitizer.cpp @@ -0,0 +1,56 @@ +/* + * Copyright (c) 2021, Andreas Kling + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include + +using namespace Kernel; +using namespace Kernel::UBSanitizer; + +extern "C" { + +static void print_location(const SourceLocation& location) +{ + dbgln("KUBSAN: at {}, line {}, column: {}", location.filename(), location.line(), location.column()); +} + +void __ubsan_handle_load_invalid_value(InvalidValueData&, void*); +void __ubsan_handle_load_invalid_value(InvalidValueData& data, void*) +{ + dbgln("KUBSAN: load-invalid-value: {} ({}-bit)", data.type.name(), data.type.bit_width()); + print_location(data.location); + dump_backtrace(); +} + +void __ubsan_handle_nonnull_arg(NonnullArgData&); +void __ubsan_handle_nonnull_arg(NonnullArgData& data) +{ + dbgln("KUBSAN: null pointer passed as argument {}, which is declared to never be null", data.argument_index); + print_location(data.location); + dump_backtrace(); +} +} diff --git a/Kernel/UBSanitizer.h b/Kernel/UBSanitizer.h new file mode 100644 index 0000000000..bf54f159b1 --- /dev/null +++ b/Kernel/UBSanitizer.h @@ -0,0 +1,77 @@ +/* + * Copyright (c) 2021, Andreas Kling + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#pragma once + +#include + +namespace Kernel::UBSanitizer { + +class SourceLocation { +public: + const char* filename() const { return m_filename; } + u32 line() const { return m_line; } + u32 column() const { return m_column; } + +private: + const char* m_filename; + u32 m_line; + u32 m_column; +}; + +enum TypeKind : u16 { + Integer = 0, + Float = 1, + Unknown = 0xffff, +}; + +class TypeDescriptor { +public: + const char* name() const { return m_name; } + TypeKind kind() const { return (TypeKind)m_kind; } + bool is_integer() const { return kind() == TypeKind::Integer; } + bool is_signed() const { return m_info & 1; } + bool is_unsigned() const { return !is_signed(); } + size_t bit_width() const { return 1 << (m_info >> 1); } + +private: + u16 m_kind; + u16 m_info; + char m_name[1]; +}; + +struct InvalidValueData { + SourceLocation location; + const TypeDescriptor& type; +}; + +struct NonnullArgData { + SourceLocation location; + SourceLocation attribute_location; + int argument_index; +}; + +}