Local/Remote Crash (DoS) in SET_CAR

[Halcy0nic]

Hi!

Love the npl tool, I think it's super creative and really easy to use.

Brief Summary

While I was using the tool I had my fuzzer running in the background and came across a local/remote crash (DoS condition) as a result of slightly malformed input. Running the tool as a daemon/service (via inetd or some other means) would cause it to crash for all users accessing npl. The issue comes from invoking the SET_CAR function on an Atom when the input is malformed.

Reproduction

I've attached the input for reproduction purposes. After running npl against the input you can see following the GDB trace:

./npl -s ./input_file

Below is the hex dump of the input file:

A similar process could be repeated for GET_CAR
files.zip

[sasagawa888]

Thank you for the bug report. I will consider how to deal with it.

[sasagawa888]

I fixed it. I changed to consult/1 from reconsult/1 in -s mode.

tests/bug.pl
.0.

npl -s tests/bug.pl
Syntax error assertz .0
around here line=1 column=0
?-

[Halcy0nic]

Sweet!

Thanks