https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81681

            Bug ID: 81681
           Summary: Memory leak in demangler
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: demangler
          Assignee: unassigned at gcc dot gnu.org
          Reporter: security-tps at google dot com
  Target Milestone: ---

Created attachment 41903
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41903&action=edit
binutils docker file

Hello GCC team,

As part of our fuzzing efforts at Google, we have identified an issue affecting
demangler (tested via git clone git://sourceware.org/git/binutils-gdb.git).  To
reproduce we are attaching a dockerfile to help compiling the project with the
LLVM taking advantage of the sanitizers that it offers.

Attached is a dockerfile that can be used for reproduction.  More information
about how to use the dockerfile can be found here: 
https://docs.docker.com/engine/reference/builder/
TL;DR instructions:
mkdir binutils
cp Dockerfile /path/to/binutils
docker build --no-cache /path/to/binutils
docker run -it <image id>
(from another terminal, outside the container):
docker cp /path/to/attached/reproducer <container id>:/fuzzing/
https://docs.docker.com/engine/reference/commandline/cp/
(back inside the container) /fuzzing/repro.sh /fuzzing/reproducer

Alternatively, and depending on the bug, you could use gcc, valgrind or other
instrumentation tools to aid in the investigation.

The sanitizer error that we encountered is here:

 ==3170==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 8 byte(s) in 1 object(s) allocated from:
      #0 0x4cd488 in __interceptor_malloc
(/fuzzing/binutils-gdb/build/demangle_fuzzer+0x4cd488)
      #1 0x52f179 in xmalloc /fuzzing/binutils-gdb/libiberty/xmalloc.c:147:12
      #2 0x50fb7e in demangle_template
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:2228:27
      #3 0x50e30d in demangle_signature
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:1691:18
      #4 0x50bc20 in internal_cplus_demangle
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:1257:14
      #5 0x50a99c in cplus_demangle
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:918:9
      #6 0x50847d in LLVMFuzzerTestOneInput
/fuzzing/binutils-gdb/build/../libiberty/demangle_fuzzer.cc:11:20
      #7 0x535eec in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*,
unsigned long) (/fuzzing/binutils-gdb/build/demangle_fuzzer+0x535eec)
      #8 0x52f3bc in main
(/fuzzing/binutils-gdb/build/demangle_fuzzer+0x52f3bc)

  Indirect leak of 1 byte(s) in 1 object(s) allocated from:
      #0 0x4cd488 in __interceptor_malloc
(/fuzzing/binutils-gdb/build/demangle_fuzzer+0x4cd488)
      #1 0x52f179 in xmalloc /fuzzing/binutils-gdb/libiberty/xmalloc.c:147:12
      #2 0x5100db in demangle_template
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:2327:31
      #3 0x50e30d in demangle_signature
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:1691:18
      #4 0x50bc20 in internal_cplus_demangle
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:1257:14
      #5 0x50a99c in cplus_demangle
/fuzzing/binutils-gdb/libiberty/cplus-dem.c:918:9
      #6 0x50847d in LLVMFuzzerTestOneInput
/fuzzing/binutils-gdb/build/../libiberty/demangle_fuzzer.cc:11:20
      #7 0x535eec in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*,
unsigned long) (/fuzzing/binutils-gdb/build/demangle_fuzzer+0x535eec)
      #8 0x52f3bc in main
(/fuzzing/binutils-gdb/build/demangle_fuzzer+0x52f3bc)

  SUMMARY: AddressSanitizer: 9 byte(s) leaked in 2 allocation(s). 

We will gladly work with you so you can successfully confirm and reproduce this
issue. Do let us know if you have any feedback surrounding the documentation.

Once you have reproduced the issue, we’d appreciate to learn your expected
timeline for an update to be released. With any fix, please attribute the
report to “Google Autofuzz project”.

We are also pleased to inform you that your project is eligible for inclusion
to the OSS-Fuzz project, which can provide additional continuous fuzzing, and
encourage you to investigate integration options
(https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md).

Don’t hesitate to let us know if you have any questions!

Google AutoFuzz Team

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