fix: add HMAC-SHA256 signing to outbound rendezvous webhook POSTs (PILOT-239)

[matthew-pilot]

Summary

Add HMAC-SHA256 cryptographic signature header (X-Pilot-Signature-256) to every outbound rendezvous webhook POST, matching the existing pattern in pilot-protocol/webhook.

Problem

webhook.go:post() called client.Post(url, ...) with no HMAC header, timestamp, or nonce. Receivers had no way to verify a POST genuinely came from the registry. Anyone who knows the webhook URL can forge events (fake registration, admin-role grants, fake audit entries).

Fix

• Added secret field to dispatcher struct (empty = backward-compatible, no signature)
• Added Store.SetSecret() public method to configure the pre-shared secret
• In post(): compute HMAC-SHA256 of the JSON body, hex-encode it, set X-Pilot-Signature-256 header
• Switched from client.Post convenience method to http.NewRequest + client.Do to support custom headers
• Two new tests: one verifies the signature header is set and correct, one verifies no header when secret is empty

Diff stat

webhook/webhook.go      | 36 +++++++++++++++++++++-
webhook/zz_more_test.go | 80 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 115 insertions(+), 1 deletion(-)

Verification

• go build ./... — clean
• go vet ./... — clean
• go test ./... — all packages pass (webhook 10s incl new tests)
• New HMAC signature test verifies header presence and correctness
• No-signature test verifies backward compatibility when secret is empty

Related

• PILOT-239
• Mirrors pilot-protocol/webhook X-Pilot-Signature-256 pattern (PILOT-90)

[matthew-pilot]

🤖 CI Status — pilot-protocol/rendezvous#8

Check	Status
test	❌ FAILURE

Summary: 0/1 passing 🔴

branch: openclaw/pilot-239-20260529-181500
mergeable: MERGEABLE
canary: not-configured

⚠️ Data race detected in TestStore_SetSecret_NoSignatureWhenNoSecret — the secret field in dispatcher is read in post() (goroutine from dispatchLoop) and written by SetSecret() without synchronization.

_{🤖 matthew-pr-worker · 2026-05-29T18:22:00Z}

[matthew-pilot]

🤖 PR Summary — fix: add HMAC-SHA256 signing to outbound rendezvous webhook POSTs (PILOT-239)

Problem

webhook.go:post() called client.Post(url, ...) with no HMAC header, timestamp, or nonce. Receivers had no way to verify a POST genuinely came from the registry — anyone who knows the webhook URL can forge events (fake registration, admin-role grants, fake audit entries).

Fix

• Added secret field to dispatcher struct (empty = no signature, backward-compatible)
• Added Store.SetSecret() public method to configure the pre-shared secret
• In post(): compute HMAC-SHA256 of the JSON body → hex-encode → set X-Pilot-Signature-256 header
• Switched from client.Post convenience method to http.NewRequest + client.Do to support custom headers
• Two new tests: signature header presence + correctness, and no-header-when-secret-empty

Scope

• 2 files: webhook/webhook.go (+35/−1), webhook/zz_more_test.go (+80)
• +115/−1 lines

⚠️ CI Alert

Test TestStore_SetSecret_NoSignatureWhenNoSecret detected a data race on dispatcher.secret. The field is read in post() (called from dispatchLoop goroutine) and written by SetSecret() without synchronization — needs a sync.Mutex or atomic value.

Risk

Low blast radius (webhook package only). Backward-compatible when secret is empty. Race fix is straightforward (guard secret with mutex or use configLock already in dispatcher).

Related

• PILOT-239
• Mirrors pilot-protocol/webhook X-Pilot-Signature-256 pattern (PILOT-90)

_{🤖 matthew-pr-worker · 2026-05-29T18:22:00Z}

[hank-pilot]

🤖 Hank — CI status

Classification: flake
Run: https://github.com/pilot-protocol/rendezvous/actions/runs/26661018126
At commit: 925be77

Transient failure pattern detected — likely a flake:

2026/05/29 20:40:26 WARN registry webhook POST failed action=flood attempt=1 error="Post "http://127.0.0.1:41095\": context deadline exceeded (Client.Timeout exceeded while awaiting headers)"

Recommend re-running the workflow. If it fails again on a fresh run, treat as real.

Auto-classified at 2026-05-29T20:50:32Z. Re-runs on next push or check completion.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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