Igor, many thanks for review! I've fixed patches and pushed to the branch (but left them as a separate commits with prefix [TO SQUASH]). On 07.12.2020 20:24, Igor Munkin wrote: > Sergey, > > Thanks for the patch! Please consider the remaining comments below. > > On 30.11.20, sergeyb@tarantool.org wrote: >> From: Sergey Bronnikov >> >> There is a number of bugs related to parsing and encoding/decoding data. >> Examples: >> >> - csv: #2692, #4497, #2692 >> - uri: #585 >> >> One of the effective method to find such issues is a fuzzing testing. >> Patch introduce a CMake flag to enable building fuzzers (ENABLE_FUZZER) > Typo: s/introduce/introduces/. Fixed. > >> and add fuzzers based on LibFuzzer [1] to csv, http_parser and uri modules. >> NOTE: LibFuzzer requires Clang compiler. >> >> [1] https://llvm.org/docs/LibFuzzer.html >> >> How-To Use: >> >> $ mkdir build && cd build >> $ CC=clang CXX=clang++ cmake -DENABLE_FUZZER=ON -DENABLE_ASAN=ON -DCMAKE_BUILD_TYPE=Debug .. >> $ make fuzzers >> $ ./test/fuzz/csv_fuzzer -max_total_time=60*60*60 -workers=4 ../test/static/corpus/csv > I tried your recipe for the current revision and got the following: > | $ ./test/fuzz/csv_fuzzer -max_total_time=60*60*60 -workers=4 ../test/static/corpus/csv > | INFO: Seed: 2899369680 > | INFO: Loaded 1 modules (3 inline 8-bit counters): 3 [0x57a130, 0x57a133), > | INFO: Loaded 1 PC tables (3 PCs): 3 [0x553870,0x5538a0), > | No such file or directory: ../test/static/corpus/csv; exiting > > AFAICS, the required directory is added in the following patch, so I > checkout the branch HEAD and try once more: > | $ ./test/fuzz/csv_fuzzer -max_total_time=60*60*60 -workers=4 ../test/static/corpus/csv > | INFO: Seed: 1838565059 > | INFO: Loaded 1 modules (3 inline 8-bit counters): 3 [0x57a130, 0x57a133), > | INFO: Loaded 1 PC tables (3 PCs): 3 [0x553870,0x5538a0), > | INFO: 21 files found in ../test/static/corpus/csv > | INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 4096 bytes > | INFO: seed corpus: files: 21 min: 1b max: 462b total: 1336b rss: 27Mb > | csv_fuzzer: /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:537: void fuzzer::Fuzzer::ExecuteCallback(const uint8_t *, size_t): Assertion `Res == 0' failed. > | ==15230== ERROR: libFuzzer: deadly signal > | #0 0x507287 in __sanitizer_print_stack_trace /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/asan/asan_stack.cc:38:3 > | #1 0x44f978 in fuzzer::PrintStackTrace() /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerUtil.cpp:206:5 > | #2 0x4300f3 in fuzzer::Fuzzer::CrashCallback() /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:237:3 > | #3 0x4300b0 in fuzzer::Fuzzer::StaticCrashSignalCallback() /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:209:6 > | #4 0x7f179300c8bf (/lib64/libpthread.so.0+0x148bf) > | #5 0x7f1792bfdf3a in gsignal (/lib64/libc.so.6+0x38f3a) > | #6 0x7f1792be7534 in abort (/lib64/libc.so.6+0x22534) > | #7 0x7f1792be740e in __tls_get_addr (/lib64/libc.so.6+0x2240e) > | #8 0x7f1792bf5731 in __assert_fail (/lib64/libc.so.6+0x30731) > | #9 0x431d06 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:537:5 > | #10 0x4310d5 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:455:3 > | #11 0x433aad in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::vector, std::allocator >, fuzzer::fuzzer_allocator, std::allocator > > > const&) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:745:7 > | #12 0x434240 in fuzzer::Fuzzer::Loop(std::vector, std::allocator >, fuzzer::fuzzer_allocator, std::allocator > > > const&) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerLoop.cpp:768:3 > | #13 0x425e60 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerDriver.cpp:760:6 > | #14 0x450132 in main /var/tmp/portage/sys-libs/compiler-rt-sanitizers-8.0.1/work/compiler-rt-8.0.1.src/lib/fuzzer/FuzzerMain.cpp:20:10 > | #15 0x7f1792be8eda in __libc_start_main (/lib64/libc.so.6+0x23eda) > | #16 0x41e919 in _start (/tarantool/build/test/fuzz/csv_fuzzer+0x41e919) > | > | NOTE: libFuzzer has rudimentary signal handlers. > | Combine libFuzzer with AddressSanitizer or similar for better crash reports. > | SUMMARY: libFuzzer: deadly signal > | MS: 0 ; base unit: 0000000000000000000000000000000000000000 > | 0x22,0x61,0x62,0x63,0x22,0x2c,0x20,0x22,0x77,0x69,0x74,0x68,0x2c,0x63,0x6f,0x6d,0x6d,0x61,0x22,0x2c,0x20,0x22,0x5c,0x22,0x69,0x6e,0x20,0x71,0x75,0x6f,0x74,0x65,0x73,0x5c,0x22,0x22,0x2c,0x20,0x22,0x31,0x20,0x5c,0x22,0x20,0x71,0x75,0x6f,0x74,0x65,0x22,0xa, \"abc\", \"with,comma\", \"\\\"in quotes\\\"\", \"1 \\\" quote\"\x0a > | artifact_prefix='./'; Test unit written to ./crash-6d131d28c6e20c3a0a0b46c3aa7308d3029ab636 > | Base64: ImFiYyIsICJ3aXRoLGNvbW1hIiwgIlwiaW4gcXVvdGVzXCIiLCAiMSBcIiBxdW90ZSIK > > I have no idea whether it is OK but this does look like it's not. Maybe > there are some problems with my compiler/sanitizer? JFYI, the toolchain > is the following: > | $ clang -v > | clang version 8.0.1 (tags/RELEASE_801/final) > | Target: x86_64-pc-linux-gnu > | Thread model: posix > | InstalledDir: /usr/lib/llvm/8/bin > | Selected GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0 > | Candidate multilib: .;@m64 > | Candidate multilib: 32;@m32 > | Selected multilib: .;@m64 > | $ clang++ -v > | clang version 8.0.1 (tags/RELEASE_801/final) > | Target: x86_64-pc-linux-gnu > | Thread model: posix > | InstalledDir: /usr/lib/llvm/8/bin > | Selected GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0 > | Candidate multilib: .;@m64 > | Candidate multilib: 32;@m32 > | Selected multilib: .;@m64 Message with assert is definitely not ok. LibFuzzer documentation says that all fuzzers must return 0 only [1]. --- a/test/fuzz/csv_fuzzer.c +++ b/test/fuzz/csv_fuzzer.c @@ -9,15 +9,14 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {          csv_create(&csv);          char *buf = calloc(size, sizeof(char*));          if (buf == NULL) -                return -1; +                return 0;          memcpy(buf, data, size);          buf[size] = '\0';          char *end = buf + size;          csv_parse_chunk(&csv, buf, end);          csv_finish_parsing(&csv); -        int rc = csv_get_error_status(&csv) == CSV_ER_INVALID ? 1 : 0;          csv_destroy(&csv);          free(buf); -        return rc; +        return 0;  } diff --git a/test/fuzz/http_parser_fuzzer.c b/test/fuzz/http_parser_fuzzer.c index a0aaf6786..f2dd7d09a 100644 --- a/test/fuzz/http_parser_fuzzer.c +++ b/test/fuzz/http_parser_fuzzer.c @@ -9,10 +9,10 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {          http_parser_create(&parser);          parser.hdr_name = (char *)calloc((int)size, sizeof(char));          if (parser.hdr_name == NULL) -                return -1; +                return 0;          char *end_buf = buf + size; -        int rc = http_parse_header_line(&parser, &buf, end_buf, size); +        http_parse_header_line(&parser, &buf, end_buf, size);          free(parser.hdr_name); -        return rc; +        return 0;  } --- a/test/fuzz/uri_fuzzer.c +++ b/test/fuzz/uri_fuzzer.c @@ -8,12 +8,12 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)  {          char *buf = calloc(size, sizeof(char*));          if (!buf) -                return -1; +                return 0;          strncpy(buf, (char*)data, size);          buf[size] = '\0';          struct uri uri; -        int rc = uri_parse(&uri, buf); +        uri_parse(&uri, buf);          free(buf); -        return rc; +        return 0;  } For the rest I believe the reason is | NOTE: libFuzzer has rudimentary signal handlers. | Combine libFuzzer with AddressSanitizer or similar for better crash reports. > >> Part of #1809 >> --- >> CMakeLists.txt | 2 +- >> cmake/profile.cmake | 13 ++++++++++ >> test/CMakeLists.txt | 3 +++ >> test/fuzz/CMakeLists.txt | 45 ++++++++++++++++++++++++++++++++++ >> test/fuzz/csv_fuzzer.c | 23 +++++++++++++++++ >> test/fuzz/http_parser_fuzzer.c | 18 ++++++++++++++ >> test/fuzz/uri_fuzzer.c | 19 ++++++++++++++ >> 7 files changed, 122 insertions(+), 1 deletion(-) >> create mode 100644 test/fuzz/CMakeLists.txt >> create mode 100644 test/fuzz/csv_fuzzer.c >> create mode 100644 test/fuzz/http_parser_fuzzer.c >> create mode 100644 test/fuzz/uri_fuzzer.c >> > > >> diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt >> index 10882c6a1..d20a4eb5d 100644 >> --- a/test/CMakeLists.txt >> +++ b/test/CMakeLists.txt >> @@ -75,6 +75,9 @@ add_subdirectory(app-tap) >> add_subdirectory(box) >> add_subdirectory(box-tap) >> add_subdirectory(unit) >> +if(ENABLE_FUZZER) >> + add_subdirectory(fuzz) >> +endif() > Minor: Well, I don't get the idea *why* this change is added here: it > neither takes the place in alphabetical order, nor is added to the end > of the list. Sure, sorted alphabetically now. --- a/test/CMakeLists.txt +++ b/test/CMakeLists.txt @@ -74,10 +74,10 @@ add_subdirectory(app)  add_subdirectory(app-tap)  add_subdirectory(box)  add_subdirectory(box-tap) -add_subdirectory(unit)  if(ENABLE_FUZZER)      add_subdirectory(fuzz)  endif() +add_subdirectory(unit)  add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/luajit/test                   ${PROJECT_BINARY_DIR}/third_party/luajit/test) >> add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/luajit/test >> ${PROJECT_BINARY_DIR}/third_party/luajit/test) >> >> diff --git a/test/fuzz/CMakeLists.txt b/test/fuzz/CMakeLists.txt >> new file mode 100644 >> index 000000000..142d38f67 >> --- /dev/null >> +++ b/test/fuzz/CMakeLists.txt >> @@ -0,0 +1,45 @@ >> +include_directories(${PROJECT_SOURCE_DIR}/src) >> +include_directories(${PROJECT_BINARY_DIR}/src) > Minor: It would be nice to explicitly mention the line above is added > for autogenerated headers and LuaJIT ones. Feel free to ignore. Fixed. --- a/test/fuzz/CMakeLists.txt +++ b/test/fuzz/CMakeLists.txt @@ -1,3 +1,4 @@ +# Added for autogenerated headers and LuaJIT ones.  include_directories(${PROJECT_SOURCE_DIR}/src)  include_directories(${PROJECT_BINARY_DIR}/src)  include_directories(${PROJECT_SOURCE_DIR}/src/box) @@ -50,8 +51,8 @@ add_executable(http_parser_fuzzer http_parser_fuzzer.c)  target_link_libraries(http_parser_fuzzer PUBLIC http_parser fuzzer_config) > >> +include_directories(${PROJECT_SOURCE_DIR}/src/box) >> + >> +# A special target with fuzzer and sanitizer flags. >> +add_library(fuzzer_config INTERFACE) >> + >> +target_compile_options( >> + fuzzer_config >> + INTERFACE >> + $<$: >> + -fsanitize=fuzzer,address >> + > >> + $<$: >> + -fsanitize=fuzzer,undefined >> + > >> +) >> +target_link_libraries( >> + fuzzer_config >> + INTERFACE >> + $<$: >> + -fsanitize=fuzzer,address >> + > >> + $<$: >> + -fsanitize=fuzzer,undefined >> + > >> +) > OK, I ran with more verbose output and have two notes > regarding it. > | Scanning dependencies of target csv > | make[3]: Leaving directory '/tarantool/build' > | make -f src/lib/csv/CMakeFiles/csv.dir/build.make src/lib/csv/CMakeFiles/csv.dir/build > | make[3]: Entering directory '/tarantool/build' > | [ 0%] Building C object src/lib/csv/CMakeFiles/csv.dir/csv.c.o > | cd /tarantool/build/src/lib/csv && /usr/lib/llvm/9/bin/clang-9 -DCORO_ASM > | -DLUAJIT_SMART_STRINGS=1 -DLUAJIT_USE_ASAN=1 -DLUA_USE_APICHECK=1 > | -DLUA_USE_ASSERT=1 -DNVALGRIND=1 -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE > | -D__STDC_CONSTANT_MACROS=1 -D__STDC_FORMAT_MACROS=1 -D__STDC_LIMIT_MACROS=1 > | -I/tarantool/src -I/tarantool/build/src -I/tarantool/src/lib > | -I/tarantool/src/lib/small -I/tarantool/src/lib/small/third_party > | -I/tarantool/src/lib/core -I/tarantool -I/tarantool/third_party/zstd/lib > | -I/tarantool/third_party/zstd/lib/common -I/tarantool/build/third_party > | -I/tarantool/third_party -I/tarantool/third_party/coro > | -I/tarantool/third_party/luajit/src -I/tarantool/third_party/libyaml/include > | -I/tarantool/src/lib/msgpuck -I/tarantool/build/build/curl/dest/include > | -I/tarantool/build/third_party/decNumber > | -I/tarantool/third_party/libutil_freebsd -fexceptions -funwind-tables > | -fno-omit-frame-pointer -fno-stack-protector -fno-common -fopenmp -msse2 > | -fsanitize=address -fsanitize-blacklist=/tarantool/asan/asan.supp > | -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts > | -Wno-gnu-alignof-expression -Werror -g -ggdb -O0 -UASAN_INTERFACE_OLD > | -o CMakeFiles/csv.dir/csv.c.o -c /tarantool/src/lib/csv/csv.c > | [ 0%] Linking C static library libcsv.a > | cd /tarantool/build/src/lib/csv && /usr/bin/cmake -P CMakeFiles/csv.dir/cmake_clean_target.cmake > | cd /tarantool/build/src/lib/csv && /usr/bin/cmake -E cmake_link_script CMakeFiles/csv.dir/link.txt --verbose=1 > | /usr/bin/ar qc libcsv.a CMakeFiles/csv.dir/csv.c.o > | /usr/bin/ranlib libcsv.a > | make[3]: Leaving directory '/tarantool/build' > | [ 0%] Built target csv > | make -f test/fuzz/CMakeFiles/csv_fuzzer.dir/build.make test/fuzz/CMakeFiles/csv_fuzzer.dir/depend > | make[3]: Entering directory '/tarantool/build' > | cd /tarantool/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" > | /tarantool /tarantool/test/fuzz /tarantool/build /tarantool/build/test/fuzz > | /tarantool/build/test/fuzz/CMakeFiles/csv_fuzzer.dir/DependInfo.cmake --color= > | Dependee "/tarantool/build/test/fuzz/CMakeFiles/csv_fuzzer.dir/DependInfo.cmake" > | is newer than depender "/tarantool/build/test/fuzz/CMakeFiles/csv_fuzzer.dir/depend.internal". > | Dependee "/tarantool/build/test/fuzz/CMakeFiles/CMakeDirectoryInformation.cmake" > | is newer than depender "/tarantool/build/test/fuzz/CMakeFiles/csv_fuzzer.dir/depend.internal". > | Scanning dependencies of target csv_fuzzer > | make[3]: Leaving directory '/tarantool/build' > | make -f test/fuzz/CMakeFiles/csv_fuzzer.dir/build.make test/fuzz/CMakeFiles/csv_fuzzer.dir/build > | make[3]: Entering directory '/tarantool/build' > | [ 0%] Building C object test/fuzz/CMakeFiles/csv_fuzzer.dir/csv_fuzzer.c.o > | cd /tarantool/build/test/fuzz && /usr/lib/llvm/9/bin/clang-9 -DCORO_ASM > | -DLUAJIT_SMART_STRINGS=1 -DLUAJIT_USE_ASAN=1 -DLUA_USE_APICHECK=1 > | -DLUA_USE_ASSERT=1 -DNVALGRIND=1 -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE > | -D__STDC_CONSTANT_MACROS=1 -D__STDC_FORMAT_MACROS=1 -D__STDC_LIMIT_MACROS=1 > | -I/tarantool/src -I/tarantool/build/src -I/tarantool/src/lib > | -I/tarantool/src/lib/small -I/tarantool/src/lib/small/third_party > | -I/tarantool/src/lib/core -I/tarantool -I/tarantool/third_party/zstd/lib > | -I/tarantool/third_party/zstd/lib/common -I/tarantool/third_party/luajit/src > | -I/tarantool/src/lib/msgpuck -I/tarantool/src/box -fexceptions > | -funwind-tables -fno-omit-frame-pointer -fno-stack-protector -fno-common -fopenmp -msse2 > | -fsanitize=address -fsanitize-blacklist=/tarantool/asan/asan.supp > | -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts > | -Wno-gnu-alignof-expression -Werror -Wno-unused-parameter -g -ggdb -O0 > | -UASAN_INTERFACE_OLD -fsanitize=fuzzer,address > | -o CMakeFiles/csv_fuzzer.dir/csv_fuzzer.c.o -c /tarantool/test/fuzz/csv_fuzzer.c > | [ 0%] Linking C executable csv_fuzzer > | cd /tarantool/build/test/fuzz && /usr/bin/cmake -E cmake_link_script CMakeFiles/csv_fuzzer.dir/link.txt --verbose=1 > | /usr/lib/llvm/9/bin/clang-9 -fexceptions -funwind-tables > | -fno-omit-frame-pointer -fno-stack-protector -fno-common -fopenmp -msse2 > | -fsanitize=address -fsanitize-blacklist=/tarantool/asan/asan.supp > | -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts > | -Wno-gnu-alignof-expression -Werror -Wno-unused-parameter -g -ggdb -O0 > | -rdynamic CMakeFiles/csv_fuzzer.dir/csv_fuzzer.c.o -o csv_fuzzer > | ../../src/lib/csv/libcsv.a -fsanitize=fuzzer,address > | make[3]: Leaving directory '/tarantool/build' > | [ 0%] Built target csv_fuzzer > > 1. I'm totally not an expert, but quite confused with the fact the > libcsv is build w/o flag, but csv_fuzzer is build with it. You are right. Project source code should be instrumented too and I enable it: diff --git a/cmake/profile.cmake b/cmake/profile.cmake index 45e3d112c..308d1b0fb 100644 --- a/cmake/profile.cmake +++ b/cmake/profile.cmake @@ -53,6 +53,9 @@ if(ENABLE_FUZZER)              " $ CC=clang CXX=clang++ cmake . <...> -DENABLE_FUZZER=ON && make -j\n"              "\n")      endif() +    if (NOT OSS_FUZZ) +        add_compile_flags("C;CXX" -fsanitize=fuzzer-no-link) +    endif()  endif()  option(ENABLE_ASAN "Enable AddressSanitizer, a fast memory error detector based on compiler instrumentation" OFF) You can easily check that option is passed to every source file (although for us interested csv, uri and http_parser libraries) when CMAKE_EXPORT_COMPILE_COMMANDS is enabled and passed to CMake. Entry for src/lib/csv.c contains -fsanitize=fuzzer-no-link in a compile_commands.json: {   "directory": "/home/sergeyb/sources/MRG/tarantool/build/src/lib/csv",   "command": "/usr/bin/clang -DCORO_ASM -DLUAJIT_SMART_STRINGS=1 -DLUA_USE_APICHECK=1 -DLUA_USE_ASSERT=1 -DNVALGRIND=1 -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS=1 -D__STDC_FORMAT_MACROS=1 -D__STDC_LIMIT_MACROS=1 -I/home/sergeyb/sources/MRG/tarantool/src -I/home/sergeyb/sources/MRG/tarantool/build/src -I/home/sergeyb/sources/MRG/tarantool/src/lib -I/home/sergeyb/sources/MRG/tarantool/src/lib/small -I/home/sergeyb/sources/MRG/tarantool/src/lib/small/third_party -I/home/sergeyb/sources/MRG/tarantool/src/lib/core -I/home/sergeyb/sources/MRG/tarantool -I/home/sergeyb/sources/MRG/tarantool/third_party/zstd/lib -I/home/sergeyb/sources/MRG/tarantool/third_party/zstd/lib/common -I/home/sergeyb/sources/MRG/tarantool/build/third_party -I/home/sergeyb/sources/MRG/tarantool/third_party -I/home/sergeyb/sources/MRG/tarantool/third_party/coro -I/home/sergeyb/sources/MRG/tarantool/third_party/luajit/src -I/home/sergeyb/sources/MRG/tarantool/third_party/libyaml/include -I/home/sergeyb/sources/MRG/tarantool/src/lib/msgpuck -I/home/sergeyb/sources/MRG/tarantool/build/build/curl/dest/include -I/home/sergeyb/sources/MRG/tarantool/build/third_party/decNumber -I/home/sergeyb/sources/MRG/tarantool/third_party/libutil_freebsd -fexceptions -funwind-tables -fno-common -fopenmp -msse2 *-fsanitize=fuzzer-no-link* -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-gnu-alignof-expression -Werror -g -ggdb -O0   -o CMakeFiles/csv.dir/csv.c.o   -c /home/sergeyb/sources/MRG/tarantool/src/lib/csv/csv.c",   "file": "/home/sergeyb/sources/MRG/tarantool/src/lib/csv/csv.c" }, You may not understand why options with "-fsanitize=fuzzer" two times (in cmake/profile.cmake and test/fuzz/CMakeLists.txt). I'll clarify it in advance: - cmake/profile.cmake is for project source files, -fsanitize=fuzzer-no-link option allows to instrument project source files for fuzzing, but LibFuzzer will not replace main() in these files. - test/fuzz/CMakeLists.txt uses -fsanitize=fuzzer and not -fsanitize=fuzzer-no-link because we want to add automatically generated main() for each fuzzer. > 2. Do you need to specify
flag once more, when ASAN is > enabled? If not the hunk above looks excess, doesn't it? Agree, it was a bad idea to manage UBSan and ASAN flags in yet another place. Moreover we don't use all flags provided by UBSan. There is an explanation in [2]. I have updated compilation and link flags in test/fuzz/CMakeLists.txt: --- a/test/fuzz/CMakeLists.txt +++ b/test/fuzz/CMakeLists.txt @@ -9,14 +9,8 @@ add_library(fuzzer_config INTERFACE)  target_compile_options(      fuzzer_config      INTERFACE -        $<$: -        -fsanitize=fuzzer,address -        > -        $<$: -        -fsanitize=fuzzer,undefined -        >          $<$>: -          -fsanitize=fuzzer +        -fsanitize=fuzzer          >          $<$:          ${CXX} @@ -26,14 +20,8 @@ target_compile_options(  target_link_libraries(      fuzzer_config      INTERFACE -        $<$: -        -fsanitize=fuzzer,address -        > -        $<$: -        -fsanitize=fuzzer,undefined -        >          $<$>: -          -fsanitize=fuzzer +        -fsanitize=fuzzer          >          $<$:          $ENV{LIB_FUZZING_ENGINE} >> + > > >> + >> +set(fuzzing_binaries csv_fuzzer >> + http_parser_fuzzer >> + uri_fuzzer) > Spaces are used for indentation in CMake-related sources, not tabs. > Surprisingly, you made it the right way below. Fixed. --- a/test/fuzz/CMakeLists.txt +++ b/test/fuzz/CMakeLists.txt @@ -1,3 +1,4 @@ +# Added for autogenerated headers and LuaJIT ones.  include_directories(${PROJECT_SOURCE_DIR}/src)  include_directories(${PROJECT_BINARY_DIR}/src)  include_directories(${PROJECT_SOURCE_DIR}/src/box) @@ -50,8 +51,8 @@ add_executable(http_parser_fuzzer http_parser_fuzzer.c)  target_link_libraries(http_parser_fuzzer PUBLIC http_parser fuzzer_config)  set(fuzzing_binaries csv_fuzzer -               http_parser_fuzzer -               uri_fuzzer) +                     http_parser_fuzzer +                     uri_fuzzer)  add_custom_target(fuzzers                    DEPENDS ${fuzzing_binaries} > >> + >> +add_custom_target(fuzzers >> + DEPENDS ${fuzzing_binaries} >> + COMMENT "Build fuzzers") >> diff --git a/test/fuzz/csv_fuzzer.c b/test/fuzz/csv_fuzzer.c >> new file mode 100644 >> index 000000000..8853d6308 >> --- /dev/null >> +++ b/test/fuzz/csv_fuzzer.c > */me feeling myself like a parrot* > > Why do you violate our style guides[1] using spaces instead of tabs for > indentation? IIRC I've already mentioned it here[2]... > > Otherwise this hunk looks fine. Fixed indentation and placed function type on the same line with function name. Code style also recommend to use goto(), but I believe that LibFuzzer someday will start to accept different exit codes and probably it is better to keep code as is without using goto(). > >> @@ -0,0 +1,23 @@ > > >> diff --git a/test/fuzz/http_parser_fuzzer.c b/test/fuzz/http_parser_fuzzer.c >> new file mode 100644 >> index 000000000..a0aaf6786 >> --- /dev/null >> +++ b/test/fuzz/http_parser_fuzzer.c > Ditto. same as for csv_fuzzer.c > >> @@ -0,0 +1,18 @@ > > >> diff --git a/test/fuzz/uri_fuzzer.c b/test/fuzz/uri_fuzzer.c >> new file mode 100644 >> index 000000000..8397505bd >> --- /dev/null >> +++ b/test/fuzz/uri_fuzzer.c > Ditto. same as for csv_fuzzer.c > >> @@ -0,0 +1,19 @@ > > >> 2.25.1 >> > [1]: https://www.tarantool.io/en/doc/latest/dev_guide/c_style_guide/#chapter-1-indentation > [2]: https://lists.tarantool.org/pipermail/tarantool-patches/2020-April/016409.html > Also added a warning that triggered when someone use ENABLE_FUZZER and OSS_FUZZ without environment variable LIB_FUZZING_ENGINE: --- a/cmake/profile.cmake +++ b/cmake/profile.cmake @@ -53,6 +53,13 @@ if(ENABLE_FUZZER)              " $ CC=clang CXX=clang++ cmake . <...> -DENABLE_FUZZER=ON && make -j\n"              "\n")      endif() +    if(OSS_FUZZ AND NOT DEFINED ENV{LIB_FUZZING_ENGINE}) +        message(SEND_ERROR +            "OSS-Fuzz builds require the environment variable " +            "LIB_FUZZING_ENGINE to be set. If you are seeing this " +            "warning, it points to a deeper problem in the ossfuzz " +            "build setup.") +    endif()      if (NOT OSS_FUZZ)          add_compile_flags("C;CXX" -fsanitize=fuzzer-no-link)      endif() 1. http://llvm.org/docs/LibFuzzer.html#id22 2. https://github.com/tarantool/tarantool/blob/master/cmake/compiler.cmake#L290-L320