Fuzzing Bind

[Siva Kakarla]

Hello Everyone,

I am trying to understand and set up a fuzzer for the Bind DNS
implementation. My current goal is to fuzz the authoritative server with
queries.

I have looked around and came across different fuzzing engines, but I have
some trouble and some questions getting it to work. If anyone has anything
to comment on, please reply, and that would be really helpful.

   1. I configured with CC=/path/to/afl/afl-clang./configure
   --enable-fuzzing=afl or afl-clang-fast to enable fuzzing. Then, I did make
   and  make install.  I then tried fuzzing the named binary with afl-fuzz
   -i fuzz/dns_message_parse.in/ -o findings /usr/local/sbin/named -gbut
   then it stops immediately, sayingthe program crashed with one of the
   test cases provided.
   1. How to fuzz the namedbinary with queries?
      2. How to get the seed input in raw format?
      3. Honggfuzz
      <https://github.com/google/honggfuzz/tree/master/examples/bind>seems
      to fuzz the named binary, but it produced too many files as crash reports
      within a minute. I have asked about it on their GitHub
      <https://github.com/google/honggfuzz/issues/408>. Anyone that worked
      with Honggfuzz, please reply.
   2. A separate fuzz folder
   <https://gitlab.isc.org/isc-projects/bind9/-/tree/main/fuzz> contains
   functions to fuzz small sections of the code.
      1. Was this created to improve coverage and modularity? (In the
      sense, can't named be fuzzed directly using the above setup?)
      2. I could get them running with oss-fuzz but how to run them with
      afl-fuzz? The README
      <https://gitlab.isc.org/isc-projects/bind9/-/blob/main/fuzz/FUZZING.md>mentions
      linking the files; can you please tell me how to do that?
   3. How to decode the packets given in
   https://gitlab.isc.org/isc-projects/bind9/-/tree/main/fuzz/dns_message_parse.in?
   How to add a new packet to the corpus? (How to convert into a raw packet?)

Thank you
Siva

--
Siva Kakarla
(sivak.dev <https://www.sivak.dev/>)
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