feat: Slice 4 — auth failure modes & token lifecycle hardening

[itlamb]

Summary

• requireAuth now correctly rejects Bearer abc (double-space token) as Malformed Authorization header (not just Invalid token)
• login use-case logs a SHA-256 hash of the email address on failure — never the plaintext email
• Patient/doctor beforeLoad guards detect an existing (but invalid) token and redirect to /login?reason=session-expired
• Login page renders a session-expired toast banner when the ?reason=session-expired search param is present
• Login page shows per-field validation errors from the 422 issues array next to the offending fields

Test plan

• pnpm verify clean (6 test files, 41 tests)
• Integration: expired/tampered/wrong-secret/empty/double-space/no-header/deleted-sub JWT cases
• Integration: 422 with both email+password errors listed; 503 on DB unreachable; 415 body
• Log event tests: auth.login.success fields; auth.login.failed contains no plaintext email
• pnpm test:e2e — tampered token → session-expired toast (requires running stack)
• pnpm test:e2e — unauthenticated → silent redirect (no toast)

Closes #4

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[claude]

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Review: Slice 4 — auth failure modes & token lifecycle

Verdict: APPROVE (with non-blocking notes)

This is a tight, well-scoped slice. It pins exactly the failure-mode polish that was missing on top of the auth groundwork from issues #1–#3, and the tests are appropriately external-behavior focused.

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Spec compliance vs. acceptance criteria

AC	Status	Where
Expired JWT → 401 Token expired	✅	require-auth.ts:31-33, test auth.test.ts:197-205
Tampered JWT → 401 Invalid token	✅	auth.test.ts:207-216
Different-secret JWT → 401 Invalid token	✅	auth.test.ts:218-226
Wrong scheme / empty / double-space → Malformed Authorization header	✅	require-auth.ts:20-27; the new token[0] === ' ' check at line 25 covers Bearer abc
Missing header → Authorization header required	✅	require-auth.ts:16-18
Deleted sub → 401 Account not found	✅	me-route.ts:25, auth.test.ts:228-243
422 lists both invalid fields	✅	auth.test.ts:93-106
415 on text/plain	✅	login-route.ts:17-19, auth.test.ts:108-118
503 on DB unreachable	✅	auth.test.ts:120-133 (uses real bad URL — no mocking, good)
Hashed-email + neutral identical 401 for wrong-creds / unknown-email	✅	login.ts:9-11,26,32; auth.test.ts:265-280
auth.login.success log fields	✅	auth.test.ts:247-263
Logger redaction (nested)	✅	already in logger.test.ts from Slice 1
Tampered token → /login + session-expired toast (e2e)	✅	auth.spec.ts:76-91
Missing token → silent /login (e2e)	✅	auth.spec.ts:69-74 (asserts toast not visible)
422 surfaces field errors in form	✅	login.tsx:66-73,113-115,131-133

All hard acceptance criteria are met.

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Architecture findings

✅ Layering is clean: route → use-case → infrastructure. No layer-skipping.
✅ Co-located tests, contracts imported from @medbridge/contracts, no any, no console.log.

⚠️ The issue's body (not the AC checklist) called for a global TanStack Query error handler on the QueryClient (onError for 401s). The implementation puts that logic in each route's beforeLoad instead (patient.tsx:10-25, doctor.tsx:10-25). Functionally equivalent for this slice (only one authenticated query exists), but the chosen pattern won't generalise — every future protected query/mutation will need to repeat the redirect-on-401 dance unless a global QueryCache({ onError }) is added. Worth a follow-up before Module 01 lands, not a blocker here.

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Security findings

✅ Wrong-creds and unknown-email return byte-identical 401 bodies and emit the same auth.login.failed event with the same emailHash shape — no user enumeration via response or log content.
✅ SHA-256 over email.toLowerCase() is consistent with the lower-cased email comparison in findUserByEmail, so log correlation works.
✅ JWT_SECRET is narrowed via Pick<AppConfig, 'JWT_SECRET'> everywhere it's passed.

Minor — none of these are blockers:

• The emailHash is unsalted SHA-256, so a known-dictionary attacker who exfiltrates logs could reverse it. Acceptable for a prototype, but worth flagging as an ADR-worthy decision before this hits any non-throwaway environment.
• require-auth.ts:25 checks token[0] === ' ' to catch the double-space case. Correct but cryptic; the comment-free style fits CLAUDE.md so I'd leave it.

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Test quality

✅ All new tests assert observable behaviour (status, body, log lines via captured sink) — no implementation-coupling.
✅ 503 test uses a real DB connection to a refused port instead of mocking. Matches the project's "no mocking the DB" rule.
✅ The plaintext-email-leak test (auth.test.ts:276-279) checks the joined log output — solid pinning test.

Gaps, all minor:

1. No log-event assertion for auth.login.db_error. The 503 test verifies status+body but not that the named log event fired. AC says "Every failure path writes the named structured log event" — this one slips through.
2. No log-event assertion for the deleted-sub case. The "Account not found" test verifies HTTP behaviour but not the log line. (get-user-profile.ts:23 emits auth.token.invalid for this case, which is reasonable but unasserted.)
3. No unit/component test for the new login-page logic — ValidationError extraction, fieldErrors, the session-expired banner. The e2e covers the toast path; the per-field error path is only covered at the API contract level.
4. The PR's own test plan has the two e2e checkboxes unticked — author flagged that they require a running stack. Worth a sanity-run before merge.

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Suggestions (non-blocking)

• 415 on the client surfaces "Invalid credentials". login.tsx:51 treats anything that isn't 200 or 422 as Error('invalid_credentials'), so a 415 / 503 from the API renders the wrong-creds banner. The issue body called for "Something went wrong" on 415 specifically. Fix this →
• Add log-event assertions for auth.login.db_error and the deleted-sub path to fully satisfy the AC line "Every failure path writes the named structured log event". Fix this →
• Migrate the redirect-on-401 logic to a global QueryCache({ onError }) in main.tsx before Module 01 introduces more authenticated queries — otherwise each new feature folder will copy the beforeLoad pattern. Fix this →
• Consider documenting the unsalted-email-hash decision in docs/ADRs/ so a future reader knows it's a deliberate prototype tradeoff, not an oversight.

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• Read linked issue Slice 4: Auth failure modes & token lifecycle hardening #4 acceptance criteria
• Read architecture rules, glossary, ADRs
• Review the diff (api + web + tests)
• Check spec compliance, architecture, security, test quality
• Post verdict
  · Branch afk/issue-4