Https-everywhere: How can I find out a Git commit corresponding to the out-of-band ruleset update?

[pipboy96]

E.g. how can I know which state of the tree the update is based on? I would like to create a script that automatically picks up new updates and tries to reproduce them from corresponding Git commits, and if they do not match, notify me so I can contact someone at EFF.

[pipboy96]

Pinging @Hainish as a developer of updater and @zoracon in case she knows.

[zoracon]

Our out of band updates are done in a separate private repo. There would be no git commit in this repo that would have a corresponding git commit #.

[pipboy96]

@zoracon I want to build a server/serverless task that tries to reproduce the updates and if they don't match, alert the owner and show the exact diff between expected and real update file.

[pipboy96]

tbh I always hate when things are done in a non-transparent way, but I can understand why EFF maintains its own closed mirror of the repo.

[zoracon]

tbh I always hate when things are done in a non-transparent way, but I can understand why EFF maintains its own closed mirror of the repo.

It's not a mirror of the repo, but rather a separate repo for ruleset releases. This was previous work done to enable frequent ruleset releases without doing a full extension update. This was heavily discussed in the open with #15096 and we now do releases for rulesets from this work.

[pipboy96]

@zoracon Does this repo only contain rulesets? Moving rulesets into a separate repo on Github too would be amazing.

[Hainish]

@pipboy96 yes that repo only contains the rulesets and ruleset signatures. It's basically a repo that stores the results of running the async-request.sh and async-airgap.sh scripts.

[pipboy96]

@Hainish I wonder what's the point of air gap if the hash to be signed is created on an online machine? I think this was asked here before. This is also the main reason why I want to make software that will try to independently reproduce these files.

[Hainish]

@pipboy96 for the same reason we use an airgap for the regular release process - it means that malware or a hacker with remote access on our machines is not able to make a release in an automated fashion. Ideally we would verify that the build results in the same hash across multiple machines before signing it. However, even without that process in place using an airgap helps mitigate against attacks. Some malware is unable to persist after a reboot (this is particularly true in Qubes). Some malware will be detected by the developer. Requiring explicit human interaction to make a release via the airgap gives us a critical opportunity to notice something is awry, and rectify the situation before something goes wrong. Will it prevent an advanced attack in every case? No. But it adds a layer of protection which disallows automated malicious releases from being made.

[pipboy96]

@Hainish To be honest, I would have simply used a YubiKey, since it would provide the same security guarantees. I would probably keep a backup copy of the key in case it breaks though.

[Hainish]

@pipboy96 last time I checked Chrome did not support using a GPG smartcard for signing extensions. Also, for the rulesets we're using raw RSA signatures, since that signature type is supported by WebCrypto in the browser without the need for external libraries.

[pipboy96]

The second case can be solved using PKCS#11.

[zoracon]

The second case can be solved using PKCS#11.

Do you mean the PKCS#11 API? If so I only saw that available in Firefox.

[pipboy96]

@zoracon no, not in the browser, but through the use of OpenSSL Engine API.

[pipboy96]

I would probably not use a regular YubiKey, but would use YubiHSM2 instead, since it supports Ed25519, which we should probably migrate to at some point of time.

[zoracon]

@pipboy96 while using a YubiKey for signing extensions would potentially streamline processes on Chrome releases, I hope the above explanations solidifies as to why there can't be external automated probes on the release process for rulesets. As of right now, we have quite a few checkpoints if files, hashes, etc. do not match up properly. For the same reasons security comes into question are the same reasons we can't have automated detection from outside scripts.

[pipboy96]

@zoracon I believe source files should be available for each update, be it ruleset or extension. I also believe GPL requires that.

[pipboy96]

@zoracon The second case I mentioned is signing rulesets themselves using OpenSSL CLI, not Chrome updates.

[zoracon]

@pipboy96 We have rulesets hosted and available on the https://atlas.eff.org for viewing exact XML files involved in a release.

[pipboy96]

Those are for extension releases though, not for out-of-band updates.

[zoracon]

@pipboy96 Sorry not atlas but https://www.https-rulesets.org (and it's JSON, not XML there).

[pipboy96]

Well, I am looking for a way to replicate this JSON (sans timestamps, compression and signatures of course) from the public GitHub repository state.

[cschanaj]

I agree with @pipboy96 that without knowing the exact commit (for the out-of-band rulesets update) made it difficult to reproduce the releases. This sometime makes it more difficult to debug some site breakage.

IMHO, it would be better to have more reproducibility on the OOB releases, e.g. by including a reference to the latest commit when a release is made. It should be fairly trivial to include git rev-parse HEAD in the releases without breaking backward compatibility.

In this way, security researchers/ interested parties can extract the gzipped releases and compare with their own build in case they have some concerns.

https://github.com/EFForg/https-everywhere/blob/ef2964aa2a83cd69d0994b67dd03498dc7139462/utils/sign-rulesets/async-request.sh#L18

[Hainish]

I don't think it should be a problem to publish which commit from HTTPS Everywhere we're deriving the out-of-band rulesets from. We usually just do it from HEAD at the point of OOB ruleset publication, but I can see how that isn't necessarily helpful and the exact HTTPSE commit would allow you to debug more efficiently.

Relatedly, currently the Atlas tracks the latest bundled rulesets, rather than ruleset releases when, for instance, in https://atlas.eff.org/domains/0xbadc0de.be.html it says Current Release. Perhaps it would be better to track the latest ruleset releases in the Atlas instead.

[pipboy96]

@Hainish Maybe make another branch for latest rulesets file?