Comment by adtac
3 days ago
Yep, certificate pinning is the one scenario Subtrace can't handle in my experience, but thankfully, it's fairly rare like you said. And IMO there is no general solution to the problem [1], but it's one of those very interesting problems to daydream thinking about when you're stuck in traffic or whatever :)
We still try our best by handling as much of the long tail of environments with some library/framework specific workaround (e.g. Deno bundles all TLS certs in its binary so we set the DENO_CERT env var when applicable).
No general solution? :) If you came up with this hack I’m sure you can extend it…
Cert pinning has to read a public cert from memory, right? And a public cert has a well-known shape… and you have bpf and access to the memory…
in a different context, maybe: https://news.ycombinator.com/item?id=38044786 :)
kubeshark [0] is using ebpf to catch calls to openssl/go's tls lib and thus no need to juggle certs. Has pros and cons compared to your method, but an interesting comparison.
[0] https://www.kubeshark.co/
The approach you describe above is common for similar projects:
- Pixie (https://px.dev) -- which I contribute to
- Beyla (https://github.com/grafana/beyla)
- Coroot (https://github.com/coroot/coroot)
If you are interested in the details and how the strategy for this tracing has evolved, you can learn more in this blog (https://blog.px.dev/ebpf-tls-tracing-past-present-future/).