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Host-built sample challenge not guaranteed to work in challenge container #384
Description
In the local testing walkthrough there's an instruction to build the challenge binary using the host toolchain:
make -C challenge
However, my Ubuntu 22.04 host builds a binary with a different glibc version requirement and this results in the challenge not running in the container:
[I][2022-08-20T20:44:18+0000] Executing '/home/user/chal' for '[STANDALONE MODE]'
/home/user/chal: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.34' not found (required by /home/user/chal)
Activity
Be more resilient to host/challenge glibc mismatch (google#384)
Be more resilient to host/challenge glibc mismatch (#384) (#385)
sroettger commentedon Aug 22, 2022
Yeah, for the GoogleCTF we solved this by building all challenge binaries in a Dockerfile themselves:
https://github.com/google/google-ctf/blob/master/2021/quals/kctf/challenge-templates/pwn/challenge/Makefile
We should probably upstream that change. The original motivation for it was to allow anyone to rebuild all challenge binaries without depending on certain packages on the host.
sroettger commentedon Aug 22, 2022
@sirdarckcat wdyt?
sirdarckcat commentedon Aug 22, 2022
I feel it's a little bit weird it's in a Makefile though (I would expect the Makefile to be called within the Dockerfile, not the other way around).
We had some ideas about making all attachments "scratch" docker images iirc? Although I don't remember how we were planning to reference them