Hi Evgeny, On Thu, 2023-09-07 at 05:31 -0700, evv… via monorail via Elfutils-devel wrote: > Comment #1 on issue 62071 by evv...@gmail.com: elfutils:fuzz-libdwfl: > Null-dereference READ in chunk_compare > https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=62071#c1 > > ``` > SCARINESS: 10 (null-deref) > #0 0x82d35d1 in chunk_compare > /src/elfutils/libelf/elf_getdata_rawchunk.c:49:25 > #1 0xf7caab3a in __tsearch > #2 0x8156826 in __interceptor_tsearch > /src/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc:6057:15 > #3 0x82d2a8a in elf_getdata_rawchunk > /src/elfutils/libelf/elf_getdata_rawchunk.c:98:28 > #4 0x81f4139 in find_elf_build_id > /src/elfutils/libdwelf/dwelf_elf_gnu_build_id.c:88:28 > #5 0x81f3a28 in __libdwfl_find_elf_build_id > /src/elfutils/libdwelf/dwelf_elf_gnu_build_id.c:142:10 > #6 0x82795e8 in __libdwfl_find_build_id > /src/elfutils/libdwfl/dwfl_module_build_id.c:70:16 > #7 0x82795e8 in dwfl_module_build_id > /src/elfutils/libdwfl/dwfl_module_build_id.c:91:20 > #8 0x81d7ec7 in dwfl_standard_find_debuginfo > /src/elfutils/libdwfl/find-debuginfo.c:365:19 > #9 0x81d3340 in find_debuginfo > /src/elfutils/libdwfl/dwfl_module_getdwarf.c:538:19 > #10 0x81cff0f in find_dw > /src/elfutils/libdwfl/dwfl_module_getdwarf.c:1412:16 > #11 0x81cff0f in dwfl_module_getdwarf > /src/elfutils/libdwfl/dwfl_module_getdwarf.c:1446:3 > #12 0x81cad03 in LLVMFuzzerTestOneInput /src/fuzz-libdwfl.c:54:3 > #13 0x808ba2e in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, > unsigned int) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:611:15 > #14 0x808b168 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned > int, bool, fuzzer::InputInfo*, bool, bool*) > /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:514:3 > #15 0x808cfdd in > fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::__Fuzzer::vector<fuzzer::SizedFile, > std::__Fuzzer::allocator<fuzzer::SizedFile> >&) > /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:826:7 > #16 0x808d1de in > fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, > std::__Fuzzer::allocator<fuzzer::SizedFile> >&) > /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:857:3 > #17 0x807c3fc in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned > char const*, unsigned int)) > /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:912:6 > #18 0x80a6177 in main > /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10 > #19 0xf7bc5ed4 in __libc_start_main > #20 0x806dad5 in _start > ``` > The fuzz target can be found at > https://github.com/google/oss-fuzz/blob/master/projects/elfutils/fuzz-libdwfl.c
Thanks. But this doesn't really get me much further. Somehow a NULL key got into the search tree and I am still unclear how that can happen. If there is a reproducer/input file that would be really helpful. Cheers, Mark
