Add preliminary NetBSD support in libfuzzer

[krytarowski]

Summary

This code already works and passes some number of tests.

There is need to finish remaining sanitizers to get better coverage.

Many tests fail due to overly long file names of executables (>31).
This is a current shortcoming of the NetBSD 8(beta) kernel, as
certain functions can fail (like retrieving file name of executable).

Sponsored by <The NetBSD Foundation>

[krytarowski]

I'm on vacation during September, I will keep pinging for this patch but not writing new code. I will be back to development in October.

[kcc]

Mostly LG

lib/fuzzer/tests/CMakeLists.txt

13

I think this should be fixed on the driver side, i.e. -fsanitize=address (and similar) should add -lrt, as they do on Linux.

[krytarowski]

lib/fuzzer/tests/CMakeLists.txt

13

It might be overlinking.. but for now I will drop this part from the commit.

[krytarowski]

• drop -lrt patch from tests

[kcc]

LGTM, thanks!

[krytarowski]

Thank you for the reviews!

In general I'm heading for tsan+msan. I need to finish proper process memory mapping.

After finishing them I will switch back to LLDB and kernel ptrace(2).

In future for lsan I need to research and add a new kernel API for StopTheWorld().

cmake/config-ix.cmake

 if (COMPILER_RT_HAS_SANITIZER_COMMON AND XRAY_SUPPORTED_ARCH AND
     OS_NAME MATCHES "Linux")
   set(COMPILER_RT_HAS_XRAY TRUE)
 else()
   set(COMPILER_RT_HAS_XRAY FALSE)
 endif()
 
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND FUZZER_SUPPORTED_ARCH AND
-      OS_NAME MATCHES "Darwin|Linux")
+      OS_NAME MATCHES "Darwin|Linux|NetBSD")
   set(COMPILER_RT_HAS_FUZZER TRUE)
 else()
   set(COMPILER_RT_HAS_FUZZER FALSE)
 endif()

lib/fuzzer/FuzzerDefs.h

 #include <vector>
 #include <set>
 #include <memory>
 
 // Platform detection.
 #ifdef __linux__
 #define LIBFUZZER_APPLE 0
 #define LIBFUZZER_LINUX 1
+#define LIBFUZZER_NETBSD 0
 #define LIBFUZZER_WINDOWS 0
 #elif __APPLE__
 #define LIBFUZZER_APPLE 1
 #define LIBFUZZER_LINUX 0
+#define LIBFUZZER_NETBSD 0
+#define LIBFUZZER_WINDOWS 0
+#elif __NetBSD__
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_NETBSD 1
 #define LIBFUZZER_WINDOWS 0
 #elif _WIN32
 #define LIBFUZZER_APPLE 0
 #define LIBFUZZER_LINUX 0
+#define LIBFUZZER_NETBSD 0
 #define LIBFUZZER_WINDOWS 1
 #else
 #error "Support for your platform has not been implemented"
 #endif
 
 #ifndef __has_attribute
 #  define __has_attribute(x) 0
 #endif
 
-#define LIBFUZZER_POSIX LIBFUZZER_APPLE || LIBFUZZER_LINUX
+#define LIBFUZZER_POSIX (LIBFUZZER_APPLE || LIBFUZZER_LINUX || LIBFUZZER_NETBSD)
 
 #ifdef __x86_64
 #  if __has_attribute(target)
 #    define ATTRIBUTE_TARGET_POPCNT __attribute__((target("popcnt")))
 #  else
 #    define ATTRIBUTE_TARGET_POPCNT
 #  endif
 #else

lib/fuzzer/FuzzerExtFunctionsWeak.cpp

 //===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Implementation for Linux. This relies on the linker's support for weak
 // symbols. We don't use this approach on Apple platforms because it requires
 // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
 // weak symbols to be undefined. That is a complication we don't want to expose
 // to clients right now.
 //===----------------------------------------------------------------------===//
 #include "FuzzerDefs.h"
-#if LIBFUZZER_LINUX
+#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD
 
 #include "FuzzerExtFunctions.h"
 #include "FuzzerIO.h"
 
 extern "C" {
 // Declare these symbols as weak to allow them to be optionally defined.
 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
   __attribute__((weak)) RETURN_TYPE NAME FUNC_SIG

 
 #include "FuzzerExtFunctions.def"
 
 #undef EXT_FUNC
 }
 
 } // namespace fuzzer
 
-#endif // LIBFUZZER_LINUX
+#endif // LIBFUZZER_LINUX || LIBFUZZER_NETBSD

lib/fuzzer/FuzzerExtraCounters.cpp

 //===- FuzzerExtraCounters.cpp - Extra coverage counters ------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Extra coverage counters defined by user code.
 //===----------------------------------------------------------------------===//
 
 #include "FuzzerDefs.h"
 
-#if LIBFUZZER_LINUX
+#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD
 __attribute__((weak)) extern uint8_t __start___libfuzzer_extra_counters;
 __attribute__((weak)) extern uint8_t __stop___libfuzzer_extra_counters;
 
 namespace fuzzer {
 uint8_t *ExtraCountersBegin() { return &__start___libfuzzer_extra_counters; }
 uint8_t *ExtraCountersEnd() { return &__stop___libfuzzer_extra_counters; }
 ATTRIBUTE_NO_SANITIZE_ALL
 void ClearExtraCounters() {  // hand-written memset, don't asan-ify.

lib/fuzzer/FuzzerUtilLinux.cpp

 //===- FuzzerUtilLinux.cpp - Misc utils for Linux. ------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Misc utils for Linux.
 //===----------------------------------------------------------------------===//
 #include "FuzzerDefs.h"
-#if LIBFUZZER_LINUX
+#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD
 
 #include <stdlib.h>
 
 namespace fuzzer {
 
 int ExecuteCommand(const std::string &Command) {
   return system(Command.c_str());
 }
 
 } // namespace fuzzer
 
-#endif // LIBFUZZER_LINUX
+#endif // LIBFUZZER_LINUX || LIBFUZZER_NETBSD

lib/fuzzer/afl/afl_driver.cpp

 #include <fstream>
 #include <iostream>
 #include <vector>
 
 // Platform detection. Copied from FuzzerInternal.h
 #ifdef __linux__
 #define LIBFUZZER_LINUX 1
 #define LIBFUZZER_APPLE 0
+#define LIBFUZZER_NETBSD 0
 #elif __APPLE__
 #define LIBFUZZER_LINUX 0
 #define LIBFUZZER_APPLE 1
+#define LIBFUZZER_NETBSD 0
+#elif __NetBSD__
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_NETBSD 1
 #else
 #error "Support for your platform has not been implemented"
 #endif
 
 // Used to avoid repeating error checking boilerplate. If cond is false, a
 // fatal error has occured in the program. In this event print error_message
 // to stderr and abort(). Otherwise do nothing. Note that setting
 // AFL_DRIVER_STDERR_DUPLICATE_FILENAME may cause error_message to be appended

 static const char *kExtraStatsFormatString = "peak_rss_mb            : %u\n"
                                              "slowest_unit_time_sec  : %u\n";
 
 // Copied from FuzzerUtil.cpp.
 size_t GetPeakRSSMb() {
   struct rusage usage;
   if (getrusage(RUSAGE_SELF, &usage))
     return 0;
-  if (LIBFUZZER_LINUX) {
+  if (LIBFUZZER_LINUX || LIBFUZZER_NETBSD) {
     // ru_maxrss is in KiB
     return usage.ru_maxrss >> 10;
   } else if (LIBFUZZER_APPLE) {
     // ru_maxrss is in bytes
     return usage.ru_maxrss >> 20;
   }
   assert(0 && "GetPeakRSSMb() is not implemented for your platform");
   return 0;

lib/fuzzer/tests/CMakeLists.txt

 set(LIBFUZZER_UNITTEST_CFLAGS
   ${COMPILER_RT_UNITTEST_CFLAGS}
   ${COMPILER_RT_GTEST_CFLAGS}
   -I${COMPILER_RT_SOURCE_DIR}/lib/fuzzer
   -fno-rtti
   -Werror
   -O2)
 
 add_custom_target(FuzzerUnitTests)
 set_target_properties(FuzzerUnitTests PROPERTIES FOLDER "Compiler-RT Tests")
 
 set(LIBFUZZER_UNITTEST_LINK_FLAGS ${COMPILER_RT_UNITTEST_LINK_FLAGS})
+if (OS_NAME MATCHES "NetBSD")
+  list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -lrt)
+endif()
 list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS --driver-mode=g++)
 
 if(APPLE)
   list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -lc++)
 else()
   list(APPEND LIBFUZZER_UNITTEST_LINK_FLAGS -lstdc++ -lpthread)
 endif()