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feat(security): inventory what image verification would refuse before it enforces - #3371
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… it enforces Enumerates every image a Talos ImageVerificationConfig rule would match from the live fleet (the only source that cannot silently miss a workload added later, since apps arrive as Flux OCIRepository artifacts and are absent from this repository), holds each to the first matching rule, and records PASS, FAIL or UNKNOWN. A cosign DENIED does not mean unsigned: GHCR answers it both for an absent signature and for a package the credential may not read. Those are separated by probing the image manifest itself, so a private package is reported UNKNOWN rather than invented as a blast radius. Part of #3334.
Verification recordExercised as a user, against the real fleet — not reasoned from the code: This reproduces, tool-independently, a manual RED → GREENRunning it is what found the bugs; none was visible by reading.
The suite: 16 checks, all passing; Ablations — five, each firing for its own reasonEvery guard was neutralised in place (never deleted, so syntax and all other paths stay intact) and
The first attempt at the last one used Control: with every guard restored, all 16 checks pass again. Scope, stated plainly
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✅
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MegaLinter runs shfmt with -i 2 -ci and fails the read-only gate when it has fixes left uncommitted. Both new scripts used one-line case arms and compact `cmd; return` sequences that the profile expands. Formatting only: the 16-check suite passes unchanged, and shellcheck is clean.
Verification record re-taken at
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@coderabbitai review |
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✅ Action performedReview finished.
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📝 WalkthroughWalkthroughAdded a fail-closed Bash tool that validates image-signature rules, enumerates Kubernetes or fixture images, verifies signatures, classifies results, and reports exit statuses. Added hermetic tests for verification, rule ordering, registry failures, invalid inputs, and empty inventories. Updated CI to run ShellCheck and the tests. Added an on-demand production workflow job with pinned Cosign installation and restored kubeconfig access. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
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Actionable comments posted: 2
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Inline comments:
In `@scripts/inventory-first-party-image-signatures.sh`:
- Around line 156-162: Update verify_signature to detect whether cosign is
available when INVENTORY_VERIFY_CMD is unset, and return status 2 immediately if
it is missing. Preserve the existing custom INVENTORY_VERIFY_CMD path and normal
cosign verification behavior when the executable is available.
- Around line 249-264: Update the status case in the manifest probe logic to
keep FAIL only for successful 2xx responses; classify HTTP 404, 429, and 5xx
responses, along with other unsuccessful statuses, as UNKNOWN without
incrementing fail. Add hermetic test cases covering 404, 429, and 500,
preserving the existing 401/403 and 000 handling.
ℹ️ Review info
⚙️ Run configuration
Configuration used: Repository YAML (base), Organization UI (inherited)
Review profile: ASSERTIVE
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Run ID: 9d33e0f7-6796-483b-b113-40db7e362916
📒 Files selected for processing (4)
.github/workflows/ci.yaml.github/workflows/validate-image-verifier-liveness.yamlscripts/inventory-first-party-image-signatures.shscripts/tests/test-inventory-first-party-image-signatures.sh
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📜 Review details
🧰 Additional context used
🧠 Learnings (1)
📚 Learning: 2026-08-10T13:01:12.782Z
Learnt from: devantler
Repo: devantler-tech/platform PR: 3057
File: .github/workflows/ci.yaml:622-659
Timestamp: 2026-08-10T13:01:12.782Z
Learning: Repository shell tests and scripts must remain compatible with macOS Bash 3.2. Do not use Bash 4+ features such as `mapfile`; use portable constructs, such as a `while IFS= read -r` loop, instead.
Applied to files:
scripts/tests/test-inventory-first-party-image-signatures.shscripts/inventory-first-party-image-signatures.sh
🪛 ast-grep (0.45.2)
scripts/tests/test-inventory-first-party-image-signatures.sh
[warning] 72-72: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 126-126: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 139-139: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 157-157: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 164-164: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 170-170: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
[warning] 195-195: set +e (or set +o errexit) disables the shell's errexit option, so the script keeps running after a command fails. This masks failures of security-critical operations (downloads, signature/checksum verification, permission changes, cleanup of secrets), letting the script proceed with a bad or insecure state. Leave errexit enabled (set -e / set -euo pipefail), or handle failures explicitly with if/|| and an explicit exit instead of globally turning off failure detection.
Context: set +e
Note: [CWE-754] Improper Check for Unusual or Exceptional Conditions.
(set-plus-e-error-masking-bash)
scripts/inventory-first-party-image-signatures.sh
[error] 138-138: eval is invoked on a variable, parameter expansion, or command-substitution result, which re-parses the value as shell code. If any part of that value is attacker-controlled (arguments, environment, file contents, network output), it allows arbitrary command execution. Do not eval dynamic data: invoke the command directly with proper quoting (e.g. "$cmd" "$arg"), use arrays for argument lists (cmd=(prog --flag "$value"); "${cmd[@]}"), or restrict input to a validated allowlist before running it.
Context: eval "$INVENTORY_ENUMERATE_CMD"
Note: [CWE-78] Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').
(eval-on-variable-bash)
Two ways the tool could report an image as one enforcement would refuse without having established anything of the kind. A manifest read that did not succeed was treated as one that did. Only 401, 403 and a dead probe were UNKNOWN; 404, 429 and every 5xx fell through to the default arm and were counted FAIL, labelled "repository readable ... would be REFUSED at pull". FAIL is now reserved for a 2xx read. And with cosign missing, every verification returns non-zero, so each image whose manifest reads 2xx was reported FAIL — an entire blast radius produced by an absent tool. That is now a prerequisite check beside the yq one, so it fails before a measurement that could not mean anything. Both overstate the blast radius the activation decision rests on, which is the same confident-but-wrong verdict as #3108 pointing the other way. Adds hermetic cases for 404, 429 and 500, a positive control that a 2xx read of an unsigned image is still FAIL, and one for the missing-cosign gate. Suite 16 -> 21.
Verification record at
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| ablation | fires |
|---|---|
default arm back to fail=$((fail + 1)) |
exactly the 3 new status checks, reason was counted as a FAIL — 401/403 and the positive control stay green |
gate condition -z → -n |
exactly cosign absent -> exit 2 |
(The first attempt at that ablation was impure — the pattern also matched unrelated *) arms
earlier in the file and changed the 401/403 counter too, which showed up as 401/403 failing
alongside. Re-aimed at the single line, and the isolated result is what the table records.)
Exercised as a user, against the real fleet — byte-identical to the run at both previous heads:
rules=3 images_enumerated=128 matched=5 PASS=3 FAIL=0 UNKNOWN=2
inventory: blast radius is non-empty or unproven — enabling enforcement is not yet a no-op
That identity is the expected result and worth stating plainly: neither fix changes what the fleet
reports today. No first-party image currently returns 404/429/5xx, and cosign is present on this
host — so both bugs were latent. They would have fired on a registry hiccup, a rate limit, or any
runner without cosign, and in each case the tool would have reported images as "would be REFUSED at
pull" that it had established nothing about. The two UNKNOWNs remain the documented fail-closed
behaviour on packages this credential cannot read; #3372 is what takes them to zero.
The gate landed beside the `command -v yq` prerequisite, which put it ahead of every rules-file check. On a runner without cosign it therefore pre-empted them, and three existing tests that assert a rules error — missing subjectRegex, empty rule set, unreadable file — got "cosign is required" instead. They passed locally only because this host has cosign installed. Moved to just after the rules are parsed and before enumeration: a malformed or unreadable rules file now reports its own error first, and the gate still runs before any work whose result could not mean anything. Adds the ordering assertion that was missing, so the precedence is pinned rather than incidental. Reproduced both states against a PATH carrying the full toolchain except cosign: the previous commit fails exactly those checks there, this one passes with cosign present and absent.
An in-place rewrite dropped the mode to 100644. MegaLinter's bash-exec linter checks exactly this, and the suite is invoked directly by the CI gate.
@coderabbitai review |
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CodeRabbit was asked first at this head and refused this round — @codex review |
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Codex Review: Didn't find any major issues. Already looking forward to the next diff. Reviewed commit: ℹ️ About Codex in GitHubYour team has set up Codex to review pull requests in this repo. Reviews are triggered when you
If Codex has suggestions, it will comment; otherwise it will react with 👍. Codex can also answer questions or update the PR. Try commenting "@codex address that feedback". |
Readiness at
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| ablation | fires |
|---|---|
default case arm back to fail=$((fail + 1)) |
exactly the 3 new 404/429/500 checks (was counted as a FAIL); 401/403 and the 2xx positive control stay green |
gate condition -z → -n |
exactly cosign absent -> exit 2 |
gate moved back beside command -v yq |
exactly the 4 rules-precedence checks, only on a cosign-free PATH |
The suite passes both with cosign present and absent — the second run against a shim directory
symlinking all of PATH except cosign, which reproduced the CI failure exactly before the fix.
2 — Reviewed. codex@60806e284c — Didn't find any major issues, Reviewed commit: 60806e284c
= head. Zero comment-form ## Review finding sections and zero finding objects at this head.
CodeRabbit was asked first and refused this round (Review rate limited, naming this head and
postdating the request), so the lane order was walked, not skipped. Its round-1 findings at
21ec2183 were both valid, both fixed, both threads resolved.
3 — Tried and evaluated as a user, against the real fleet at this head:
rules=3 images_enumerated=127 matched=4 PASS=2 FAIL=0 UNKNOWN=2
inventory: blast radius is non-empty or unproven — enabling enforcement is not yet a no-op
128/5/PASS=3) and the difference is the fleet, not the
code. doggy-countdown is no longer running — confirmed directly against the cluster, which now
reports 435 container images and no pod on that image. The tool enumerates live pods, so it tracks
that. Worth stating rather than glossing: a changed number in a security measurement should always be
attributed before it is accepted, and here the enumeration falling 128 → 127 alongside exactly one
disappearing match is consistent with the workload going away and not with a matcher regression —
the three surviving rules and both UNKNOWNs are unchanged.
The two UNKNOWNs remain the documented fail-closed behaviour on packages this credential cannot
read. #3372 wires the GHCR pull credential in and is what takes this to zero-UNKNOWN, which is
#3334's close condition.
Promoting and enqueuing.
Why
Node-level image verification is configured but has never made a decision, and turning it on
converts every unsigned first-party image into a simultaneous
ImagePullBackOffacross the fleet.Nobody could say how many images that is, so activating the control was a guess. This measures it.
The answer today: nothing that we can read would be refused. Three of the five first-party
images running on prod verify, none fails, and two are private packages the local credential cannot
read — recorded as unknown rather than assumed either way.
What
A tool that lists every image the verification rules would match, checks each against the identity
that rule requires, and reports pass, fail or unknown — plus its own test suite gating every PR, and
an on-demand job that runs the real measurement against prod. The rules are read from the existing
config file, never restated, so the tool cannot drift from what the fleet enforces.
It refuses to report an all-clear it did not earn: an empty enumeration, a broken matcher, or an
unreadable image is an error or an unknown, never "nothing to fix".
Part of #3334.