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windmill/.github
Ruben Fiszel b4c834f3cd ci: run Codex/Pi review on fork PRs when a maintainer triggers it (#10069)
* ci: run Codex review on fork PRs when a maintainer triggers it

The fork skip in codex-pr-review.yml unconditionally bailed on
cross-repository PRs, so even a maintainer's /codex or /review comment
(routed through pr-review-commands.yml via workflow_call, gated by
check-write-access) skipped external PRs.

Gate the skip on the automatic pull_request trigger only, detected via
an empty INPUT_PR_NUMBER (the metadata step already branches on this at
the same step). The workflow_call path now reviews fork PRs; the auto
pull_request trigger still skips them.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: run Pi review on fork PRs when a maintainer triggers it

Apply the same fork-skip gating as the Codex review: skip fork PRs only
on the automatic pull_request trigger (empty INPUT_PR_NUMBER), so a
maintainer's /pi or /review comment (workflow_call, gated by
check-write-access) reviews external PRs.

Claude's pr-ready-review.yml needs no change: it has no fork skip, checks
out main (not the fork ref), and reviews via gh pr diff/view with a
restricted tool allowlist, so it already handles fork PRs on the command
path.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: harden fork-review path against secret exfiltration

Addresses the CI review of the fork-review enablement. On the fork path
(maintainer-triggered workflow_call for a cross-repository PR), the
reviewer ran an autonomous agent over the attacker-controlled merge
checkout with the EE token present, full-access sandbox, and the review
prompt itself read from that untrusted checkout — so a malicious fork
could rewrite the reviewer's own instructions to exfiltrate secrets.

For fork PRs only (detected via the is_fork step output):
- withhold WINDMILL_EE_PRIVATE_ACCESS: skip the EE access/checkout/
  substitution steps, so the private-repo token is never in the env.
- read REVIEW.md and the prompt file from the trusted base ref
  (git show origin/<base>:...) instead of the merge checkout.
- restrict the agent: Codex runs with -s workspace-write (network off)
  instead of danger-full-access; Pi drops the bash tool.

Non-fork PRs are unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: redact provider credentials from fork review comments

The model call needs the provider credential in its environment/config, so a
network-disabled sandbox alone can't stop a prompt-injected fork review from
reading the key (Codex: $HOME/.codex/auth.json; Pi: /proc/self/environ) and
emitting it in the final message, which both workflows post verbatim. GitHub
Actions log masking does not cover comments posted via the API.

Strip the known credential values (OpenAI key + raw Codex auth JSON and its
nested tokens; DeepSeek key) from the review body before posting, closing the
comment as an exfiltration channel. Applied unconditionally since a credential
should never appear in a review comment regardless of trigger.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: don't persist github.token in fork review checkout

actions/checkout writes github.token into .git/config (http.extraheader) by
default. The review agent can read the checked-out tree, so on the fork path a
prompt injection could exfiltrate that token (issue/PR write) via .git/config —
the provider-credential redaction added earlier didn't cover it.

Set persist-credentials: false on the merge-ref checkout so the token is never
written to disk. Safe on both paths: the only later git op is an unauthenticated
fetch from the public origin, EE checkout uses its own token, and gh uses
GH_TOKEN. Also redact github.token from the posted comment as defense-in-depth.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: disable Pi project-local discovery on fork reviews

Pi auto-discovers and executes project-local .pi extensions (.ts/.js) at
startup with DEEPSEEK_API_KEY in its environment — before the --tools allowlist
applies — so a fork could add an extension that exfiltrates the key over the
network, which output redaction can't catch.

On the fork path (cwd is the fork checkout), pass --no-extensions to disable
extension discovery, plus --no-skills/--no-prompt-templates/--no-themes/
--no-context-files so fork-controlled skills, templates, themes, and
AGENTS.md/CLAUDE.md aren't auto-loaded into the reviewer's prompt as an
injection vector. Non-fork behavior unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: use unguessable delimiter for untrusted PR metadata outputs

The PR title/body were written to $GITHUB_OUTPUT with a fixed heredoc
terminator (PR_BODY_EOF). A fork author could embed that terminator in their PR
body to close the heredoc early and append their own output lines — e.g.
is_fork=false, which (last-write-wins) overrides the real is_fork=true and puts
fork code back on the trusted path (EE checkout + substitute_ee_code.sh with the
private token, full-access agent).

Generate a per-run random delimiter (128 bits from /dev/urandom) for the title
and body heredocs so the terminator can't be predicted or embedded. Everything
else in the block is single-line and newline-free, so this closes the injection.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: set PI_OFFLINE=1 on fork Pi reviews to block package resolution

--no-extensions only filters which resources are *loaded*; Pi still resolves
packages declared in a fork's .pi/settings.json first, running `npm install` /
the configured npmCommand and lifecycle scripts with DEEPSEEK_API_KEY in env and
network available — before the extension filter applies.

Set PI_OFFLINE=1 on the fork path so the resolver's installMissing() short-
circuits (returns false) for every missing package, skipping all install/clone/
lifecycle execution. It gates only startup network ops (installs, helper-binary
downloads), not the provider inference call, so the review still runs. Verified:
a fork .pi/settings.json with a malicious npmCommand does not execute under the
flag. Non-fork path unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: run fork Pi review from an isolated dir to cut off project config

Root cause of the recurring fork-review exposure: Pi resolves every project
config from <cwd>/.pi — settings/packages, extensions, skills, themes, prompts,
SYSTEM.md, APPEND_SYSTEM.md — so running inside the fork checkout let a fork
inject any of them to execute code or rewrite the reviewer's system prompt with
DEEPSEEK_API_KEY in env. Per-flag opt-outs (--no-extensions, PI_OFFLINE, ...)
only covered discovered vectors one at a time (SYSTEM.md wasn't covered).

Discovery is cwd-based (single level, no walk-up; global fallback is the trusted
runner home), so run Pi from a fresh mktemp dir where no fork .pi/* is on the
path. The fork agent has no shell, so pre-compute the diff (base...head SHAs are
trusted) into the context file it reads; it may still read fork files by
absolute path for extra context — reads are safe, only config discovery and code
execution were the risk. Outputs now use absolute workspace paths since cwd
moved. The --no-* flags and PI_OFFLINE stay as belt-and-suspenders. Non-fork
path unchanged. Verified: a fork .pi/SYSTEM.md sentinel is not discovered from
the isolated cwd.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: keep review artifacts outside the checkout to defeat symlink writes

Both workflows wrote generated files (final message, event stream, review
context, prior-comments) into $GITHUB_WORKSPACE. On the fork path the merge tree
is attacker-controlled, so a fork could commit any of those paths as a symlink
(e.g. codex-final-message.md -> ../../_actions/actions/github-script/v7/dist/
index.js). Our write would follow it and overwrite the next action's code, which
then executes with the provider credential and the write-capable GitHub token —
no prompt injection required.

Route every generated file through $RUNNER_TEMP, which is runner-created and
outside the checkout, so no fork-committed symlink is on the path:
- prior-comments.json and pr-review-context.md are written to RUNNER_TEMP; the
  context step reads prior-comments from there.
- The agent is given the context file's absolute RUNNER_TEMP path (appended to
  the prompt); prompt files updated to reference it instead of a checkout-
  relative path. Pi (no shell on forks) gets the diff pre-computed into that
  context file; the isolated-cwd hardening is retained.
- Codex writes -o to RUNNER_TEMP; Pi writes its events/final message there; both
  post steps read from RUNNER_TEMP.

Non-fork behavior is functionally unchanged (trusted checkout; same review
inputs, now sourced from RUNNER_TEMP).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* ci: condense fork-review comments to the 4-line limit

AGENTS.md requires each invariant stated in <=4 lines. Trim the security
comments added in this branch (fork-skip rationale, output delimiter, isolated
cwd, RUNNER_TEMP artifacts, credential redaction) to comply without dropping the
constraint each one records.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-14 12:16:49 +02:00
..
2022-05-05 10:50:54 +02:00