[#1246] Migrate referral POST endpoints to SIWE auth

[realproject7]

Summary

• Migrates register-referral POST and referral-code POST from verifyWalletOwnership (signature-recovery only) to verifySiweRequest (full EIP-4361: domain, URI, chainId, statement, 10-min freshness)
• Closes activation-signature-replay attack surface (R2/R22)
• GET /api/airdrop/referral-code preserved unauthenticated — ShareButtons/useReferralCode compatibility
• Zero remaining verifyWalletOwnership calls in mutation endpoints (grep verified)
• POST response shapes unchanged

Security

Intercepted activation {message, signature} pairs can no longer be replayed against referral mutation endpoints after the 10-min SIWE freshness window.

Version

1.33.0 → 1.33.1

🤖 Generated with Claude Code

Closes #1246

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
plotlink	Ignored		May 26, 2026 7:14am

[realproject7]

@re2 review — APPROVE ✅

Checked against issue #1246 acceptance criteria:

Criterion	Status
Both POST endpoints reject expired (>10 min) sigs → 401	✅ via verifySiweRequest
Both POST endpoints reject wrong domain/URI/chainId → 401	✅
Valid POST → existing behavior unchanged	✅ only auth path changed
GET /api/airdrop/referral-code remains unauthenticated	✅ GET handlers untouched
No remaining verifyWalletOwnership in v5 mutations	✅ (grep verified per PR)
Version 1.33.0 → 1.33.1 (patch)	✅
Lockfile synced	✅

Code review notes:

• Surgical 2-file change: import swap + auth pattern update, nothing else touched
• Signature type relaxed from `0x${string}` to string — correct for verifySiweRequest API
• auth.error now returned in 401 response — provides typed error info to clients (domain_mismatch, expired, etc.)
• Rate limiting preserved on both endpoints
• Closes R2/R22 replay attack surface within SIWE freshness window

Clean security fix. No issues found.

[project7-interns]

Verdict: REQUEST CHANGES

Summary

The code change appears to move both referral POST handlers to verifySiweRequest while leaving GET unauthenticated, which is the intended direction. However, this PR is a critical security migration and it adds no endpoint-level tests for the #1246 acceptance criteria.

Findings

• [high] The PR does not add route tests proving the two mutation endpoints now enforce SIWE semantics and preserve existing behavior. #1246 explicitly requires both POST endpoints to reject expired replay attempts and wrong domain/URI/chainId signatures with 401, valid signatures to keep existing behavior unchanged, and GET /api/airdrop/referral-code to remain unauthenticated with the existing { code, is_farcaster_username? } response shape. Existing lib/airdrop/siwe-verify.test.ts covers the helper, but it does not prove these two endpoints are wired to it correctly or that failed auth avoids referral/code writes.
  • File: src/app/api/airdrop/register-referral/route.ts:79
  • File: src/app/api/airdrop/referral-code/route.ts:63
  • Suggestion: Add focused route tests for both POST handlers that mock verifySiweRequest returning expired, domain_mismatch, uri_mismatch, and chain_id_mismatch and assert 401/no DB mutation; add valid-SIWE tests for the existing success paths; and add a GET referral-code test confirming no auth is required and the response shape is unchanged.

Decision

Requesting changes until the security acceptance criteria are covered at the endpoint boundary. CI was still pending at review time.

[project7-interns]

Verdict: APPROVE

Summary

The requested endpoint-level coverage has been added. Both referral mutation endpoints now use verifySiweRequest, auth failures return 401 without inserts, valid SIWE preserves the success flows, and referral-code GET remains unauthenticated with the expected response shape.

Findings

• None blocking.

Decision

Approving PR #1284. The security migration is scoped to the intended POST handlers, GET behavior is preserved, and the new route tests cover the reviewer-requested boundary behavior. CI was still pending at review time.

[project7-interns]

Verdict: APPROVE

Summary

Re-reviewed the latest head after the test-only lint/type fixes. The referral POST SIWE migration and endpoint-level coverage remain intact, and the latest changes only replace the GET test request mock with NextRequest.

Findings

• None blocking.

Decision

Approving PR #1284 on the latest head. CI was still pending at review time; separately, Head has already requested the PR body metadata update to include Closes #1246 before merge.