Lock Your GitHub Actions (hugovk.dev)

273 points by gslin 14 hours ago

woodruffw 14 hours ago

The advice here is really great (as I'd expect from Hugo), but as the maintainer of zizmor I want to note some caveats with the current iteration of workflow lockfiles:

- They only lock normal action calls. If your workflows invoke other reusable workflows, you need to keep those hash-pinned manually for now.

- Composite actions are not themselves locked. Instead, they get locked transitively through their callsites i.e. the workflows that call them. This makes any individual caller that uses lockfiles safe, but it also makes the current `gh actions-lock` default unsafe (since it removes hash-pins from the composite action itself, meaning that any external caller that invokes the action loses their transitive pinning).

- Other forms of `uses:` clauses, like Docker images, are also not currently locked via the lockfile. And the same for forms of interior mutability (like an action running `npx ...` under the hood, although the latter is fully outside of GitHub's control to prevent. But these mean that you can't assume that a fully locked Actions setup is in fact 100% immutable.

I hope they address these gaps soon, because it's otherwise an excellent (and long-awaited) feature.

crote 3 hours ago

And, the one often forgotten: `runs-on:` also refers to an image, but in practice a huge amount of people will just set it to `ubuntu-latest` and accept whatever GH happens to include that day. In fact, I don't think it is even possible to refer to a specific runner image revision by digest...

Already__Taken 14 hours ago

Quoting someone else's blog I've forgotten but you're trading the trust in the repo owner not moving a tag for trusting whoever merges the commit hash to have checked that's a release in the repo you want and not _some_ forks commit. All forks on github are the same repo you can pin any commit, merged upstream or not.

IMO Github should make Immutable tags mandatory to publish on https://github.com/marketplace

woodruffw 14 hours ago

Actions lockfiles prevent this. They won't allow you to lock an impostor commit, which is the right default.

(The previous way to provide general actions immutability, i.e. hash-pinning, had this issue and thus required additional checks.)

OptionOfT 14 hours ago

One could write an action that executes a shell script that does docker pull abc:latest.

As the consumer of an action that becomes really hard to find out unless I take the whole codebase apart.

eviks 5 hours ago

Why not make the marketplace published tags immutable instead like others do?

Bnjoroge 7 hours ago

That’s exactly what lockfiles are intended to avoid!

chrisweekly 13 hours ago

I almost forgot about that completely outrageous treatment of forks -- just bonkers.

klodolph 13 hours ago

I think my main advice is to avoid GH actions at all, unless avoiding them is somehow painful. There is just a long bad history here.

jaggederest 13 hours ago

These days setting up a proper system on your build orchestrator of choice is pretty easy, cheaper, and you basically only lose a tiny bit of UI niceness if they report to github anyway

ethin 10 hours ago

Only if your not on GH free, which I use for my OSS projects for example.

dirtbag__dad 10 hours ago

What would you suggest instead?

klodolph 9 hours ago

Just about anything else, tbh. Jenkins is the option I would go for, but that’s a reflection of my personal preferences for self-hosting. Self-hosting has gotten way easier since LLMs can debug things so well, so I’m self-hosting more than ever before even though I have less time available.

You don’t have to go Jenkins, it’s just that GitHub Actions are uniquely bad and I would avoid them.

If you are relying on the free version of GitHub actions for small projects, I would consider just running something on a NUC or Pi at home.

cedws 6 hours ago

pie_flavor 9 hours ago

spoaceman7777 3 hours ago

cron and bash

mitxela 6 hours ago

The whole system is just bad. Even Jenkins is better. Or a shell script in a one minute cronjob.

gbraad 13 hours ago

I undrrstand this looks cleaner and more intuitive, but you still have the risk of running a workflow with malicious/compromised actions, like manually, or locally with act, if you do not verify the lockfile as part of the workflow or preceded by an extra workflow step. This should be something that the runner ideally should handle (as part of the platform). This still is a workaround, just like the sha pinning. I only use vendor upstream actions, like github's or forks in our own org.

Bnjoroge 7 hours ago

say more about how you would envision the runner handling this? An allowlist of actions?

computerfriend 3 hours ago

The runner should execute gh actions-lock --verify automatically.

SchemaLoad 14 hours ago

Are people finding a real need for importing and updating git actions? Aren't they usually just running a one line bash command? I'd just copy paste the action in to your config so it's fully locked and under your control rather than importing some opaque script from a no name github user.

comradesmith 11 hours ago

Github actions are not that simple. Not even close

knocte 8 hours ago

Still, I prefer to copy their action.yml into my repo.

(I simply put a comment with the upstream URL in my repo in case I want to update in the future.)

Pxtl 8 hours ago

A lot of things that should be one bash command turn out to be dozens of lines of incantations and handling edge cases. Microsoft I'm looking in your direction.

For those things an action helps.

lukasschwab 14 hours ago

Are there clear reasons to prefer this over just pinning a commit SHA?

Arbortheus 13 hours ago

Presumably it’s for the transitive dependencies. You pin action X, but that (third party) action doesn’t correctly pin the SHA of action Y, so you still get owned if the mutable tag gets moved to a compromised commit.

But with a lockfile, direct and indirect dependencies both get pinned. (I presume, and haven’t checked yet, but otherwise this feature would be useless)

esafak 11 hours ago

     Use the gh actions-lock extension for the GitHub CLI to generate .github/workflows/actions.lock for actions and their transitive dependencies.
https://github.blog/changelog/2026-10-28-github-actions-work...

ygouzerh 6 hours ago

You can keep the information provided by the version number, and if the maintainer is using real SemVer, it's easier to upgrade.

akoboldfrying 8 minutes ago

> You can keep the information provided by the version number

The old way of just writing this in a comment on the same line seems fine to me -- intuitive and much more concise.

> if the maintainer is using real SemVer, it's easier to upgrade

Could you elaborate on this? I didn't see how yet.

rurban 3 hours ago

No, I'm still keep using 'pinact run -u', and some dependabot actions to remind me on updates.

ezekg 14 hours ago

Does this prevent one of the locked dependencies not locking their own dependencies and pulling in a malicious and replaced tag?

eddythompson80 14 hours ago

It does not. Obviously if you lock a “foo/setup-latest-go” action, it’s still going to (and you’d probably expect it to) pull in the latest go. Actions are expected to start running though. Like GitHub isn’t gonna do an `npm install` for you, it’ll just run the entry point of the action, and the entry point can do whatever it was written to do.

computerfriend 13 hours ago

I think they mean specifically sub-actions as dependencies.

transitivebs 11 hours ago

big fan of actions-up for doing this: https://github.com/azat-io/actions-up

latexr 13 hours ago

I remember reading (but haven’t verified) that even using a specific SHA instead of a tag isn’t a guarantee with GitHub Actions, because the Action itself may have a dependency which does not pin to a SHA, thus making you vulnerable all the same. This lock file strategy does not appear to guard agains that, it seems to be what we had before but trades a bit more readability in one file for an extra (more complex) lock file. Not a trade-off I want to make (but you do you).

Personally I found the risk of running someone else’s GitHub Action in my repo to not be worth it. Even GitHub’s own Action to checkout repos is way more complex than I need it to be and last I checked had dependencies which could be targeted. I opt instead to not run any third-party Actions (not even GitHub’s official ones) in my repos.

hobofan 7 hours ago

Does nobody read the blog post and liked Github release annoucment anymore?

This is a new first-party feature by Github to allow locking of transitive dependencies.

latexr 2 hours ago

I did read the blog post. More than once, in search for info on transitive dependencies. It doesn’t provide it. You’re right that I should’ve clicked through the official blog post, I got link blindness. I did find it strange that transitive dependencies weren’t included, which is why I repeatedly said it seemed it didn’t. Thank you for the correction.

Your snark is unwarranted, though, since the crux of the comment is not using any Action you haven’t built. Lockfiles don’t solve the complexity and trust problem.

hobofan 2 hours ago

Bnjoroge 7 hours ago

Cosign. It’s the entire point of this article and would be obvious if someone read

carterschonwald 12 hours ago

at this point im seriously pondering how to build a dvcs code forge thats not dog shit, versions its own state, and actually is semantically grounded rather than a rails app gone awry

aleaph 13 hours ago

So "SHA pinning with version reference in a comment" with extra steps, got it

sleepytimetea 11 hours ago

Yes, I scratched my head trying to understand what this accomplishes. It just puts a tag back instead of a SHA but now moves the SHA (locked in) to a separate file that now needs to be verified ? I fail to see how this is better or needed.

hobofan 7 hours ago

You can still use the SHA if you want to. What it achieves is transitive pinning (which this post doesn't properly highlight).

Lack of transitive pinning support was the biggest supply-chain security criticism against GHA and I'm glad they are finally tackling it!

edelbitter 10 hours ago

SHA pinning on GitHub does not always imply account pinning, even where the account name is explicitly specified along with it.

So some of the extra steps are meaningful. Though I am still not convinced they could not have been implemented in a deliberately backwards-incompatible way to Github action in general, keeping the syntax and removing only the special case that is never both intentional and non-malicious at the same time.

OptionOfT 13 hours ago

Enforced through GitHub Actions that is :)

Pxtl 8 hours ago

If GitHub really cared about security they could fix this tomorrow by declaring any tag linked to an action immutable.

They don't because they don't.

Anybody who's ever moved a git tag knows the ergonomics of doing so are so awful that you're obviously not supposed to be doing it.

eviks 5 hours ago

What tools did you use to get that awfulness?

numbsafari 10 hours ago

Shouldn’t we all just be vibe coding our own actions instead of using the marketplace ones? Is SaaS dead yet, or what?

/s

This is a step in the right direction, but it’s not even close to a complete solution. And what am I doing installing a plugin to use this? It should just be part of GH, so I can install that and not have yet another source of dependency management to lock down.

edelbitter 10 hours ago

So instead of specifying a SHA1 hash of some commit and change it rarely enough to just check manually, now every developer needs to unsafe-eval some 476 transitive dependencies of the helper that fixes the lockfile? I wonder at which point it gets easier to just have a nice stdlib again, and not deal with tons and tons of version changes in packages across 3 different language ecosystems.

insanitybit 9 hours ago

ctrl + f "zizmor" 8 found

I endose this article.