Security: Fix timing-unsafe bridge admin check and secure agent API mutations

[Stevenn28]

Description\n\nCloses #5000\nCloses #5009\n\nThis PR fixes two security vulnerabilities:\n\n1. Timing-unsafe bridge API (#5000): Changed the direct string comparison key != BRIDGE_ADMIN_KEY to the timing-safe hmac.compare_digest(key, BRIDGE_ADMIN_KEY) inside bridge/bridge_api.py to prevent observable timing discrepancies that could lead to key recovery.\n\n2. Unauthenticated Agent relationships mutation (#5009): Added a @require_admin decorator inside agent_relationships.py to protect the /disagree, /collaborate, /reconcile, and /intervene POST endpoints. Previously these endpoints were totally unauthenticated, allowing any user to maliciously alter agent relationships and manipulate trust scores.

[github-actions]

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[508704820]

Code Review: Fix timing-unsafe bridge admin check and secure relationship mutations

Summary

Combines two security fixes:

1. Bridge API timing-unsafe admin key comparison (same as our fix(#5000): timing-safe admin key comparison in bridge API #5001)
2. Agent relationship endpoint auth (same as our fix(#5009): add admin auth to agent relationship mutation endpoints #5010)

Comparison with our PRs

Aspect	#5001/#5010 (Xeophon)	#5014 (Stevenn28)
Bridge timing fix	Yes	Yes
Relationship auth	Yes	Yes (decorator pattern)
Auth pattern	Inline _require_admin()	@require_admin decorator
Error code when no key	403	500 (bridge), 500 (relationships)

Notes

1. The decorator pattern (@require_admin) is cleaner than inline _require_admin()
2. Returns 500 when admin key not configured — this reveals server configuration (our PRs use 403/401)
3. Both approaches use hmac.compare_digest — correct!

Both PRs fix the same bugs. #5014 uses a cleaner decorator pattern but reveals more info via 500 errors.

Review quality: Comparative review

[galpetame]

@galpetame requesting changes after local validation.

The bridge compare_digest() change itself is directionally right, and the existing relationship tests still pass, but this PR introduces/keeps a few merge blockers that should be fixed before landing:

1. The new admin guards in contributor_registry.py, payout_ledger.py, and bounties/issue-2285/src/memory_routes.py accept admin_key from the URL query string:

req_key = request.headers.get("X-Admin-Key") or request.args.get("admin_key")
if req_key != ADMIN_KEY:

That puts an admin secret into URLs, browser history, proxy/server logs, referrers, and monitoring tools. It also keeps direct string equality instead of hmac.compare_digest(). I verified this on contributor_registry.py: /approve/probeuser?admin_key=secret-query-probe returned 302, while the same route without a key returned 401.

2. The no-config path leaks server configuration as HTTP 500. Probes:

POST /bridge/release with no BRIDGE_ADMIN_KEY -> 500 {"error": "admin key not configured on server"}
POST /api/relationships/a/b/disagree with no RELATIONSHIPS_ADMIN_KEY -> 500 {"error": "relationships admin key not configured on server"}

For auth guards, this should fail closed with a generic 401/403 rather than exposing exact server config state to unauthenticated callers.

3. git diff --check origin/main...HEAD -- agent_relationships.py bridge\bridge_api.py contributor_registry.py payout_ledger.py bounties\issue-2285\src\memory_routes.py node\machine_passport_api.py fails:

agent_relationships.py:1039: trailing whitespace.
contributor_registry.py:162: trailing whitespace.
node/machine_passport_api.py:212: trailing whitespace.
node/machine_passport_api.py:313: trailing whitespace.

Validation I ran:

pytest test_agent_relationships.py -q -> 40 passed
pytest bridge\test_bridge_api.py -q -> 31 passed after creating C:\tmp for the repo's Windows /tmp test paths
python -m py_compile agent_relationships.py bridge\bridge_api.py contributor_registry.py payout_ledger.py bounties\issue-2285\src\memory_routes.py node\machine_passport_api.py -> passed
python tools\bcos_spdx_check.py --base-ref origin/main -> BCOS SPDX check: OK
git diff --check ... -> failed on the whitespace above

Suggested fix: keep admin keys header-only, compare with hmac.compare_digest(), return a generic fail-closed 401/403 when an admin key is not configured, and remove the whitespace errors.

Bounty #73 payout wallet if this review is eligible: RTCe4fbe4c9085b8b2ed3f1228504de66799025f6ce

[loganoe]

I found merge blockers in this PR. The bridge compare-digest change is directionally good, but the broader patch leaves several affected checks red.

Findings:

• agent_relationships.py:1036 re-imports os inside create_relationship_blueprint even though the module already imports it at line 29; targeted ruff reports F811.
• git diff --check origin/main...HEAD fails on trailing whitespace in agent_relationships.py, contributor_registry.py, and node/machine_passport_api.py.
• The memory route tests are not updated for the new clear auth behavior: bounties/issue-2285/tests/test_memory_routes.py::MemoryRoutesTestCase::test_clear_memory now gets 403 instead of 200.
• Contributor registry and machine passport tests are still written for the old auth/validation contract: duplicate registration posts an invalid new wallet and no longer reaches duplicate handling; unauthenticated approve now gets 403; machine passport create-without-admin now gets 401, causing update auth tests to hit 404 setup failures.
• The admin guards added in contributor_registry.py, payout_ledger.py, and bounties/issue-2285/src/memory_routes.py still accept admin_key from the query string and use direct string equality. For a security hardening PR, please keep admin secrets header-only and use hmac.compare_digest.

Validation run:

• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 uv run --no-project --with pytest --with flask python -m pytest test_agent_relationships.py -q -> 40 passed
• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 uv run --no-project --with pytest --with flask --with flask-cors --with pyyaml --with pycryptodome --with prometheus-client python -m pytest bridge/test_bridge_api.py -q -> 31 passed
• PYTHONPATH=bounties/issue-2285/src ... pytest bounties/issue-2285/tests/test_memory_routes.py -q -> 1 failed, 29 passed, 11 subtests passed
• ... pytest tests/test_contributor_registry.py tests/test_payout_ledger_migration.py tests/test_machine_passport_event_json_validation.py node/tests/test_machine_passport.py -q -> 5 failed, 40 passed
• python3 -m py_compile agent_relationships.py bridge/bridge_api.py contributor_registry.py payout_ledger.py bounties/issue-2285/src/memory_routes.py node/machine_passport_api.py -> passed
• uv run --no-project --with ruff ruff check ... --select E9,F821,F811,F841 --output-format=concise -> F811 in agent_relationships.py

Please clean up the lint/diff issues, remove query-string admin credentials, and update the affected auth tests before merge.

[jaxint]

LGTM! Thanks for contributing. Approved.

[TJCurnutte]

I found a blocker in the new admin gates.

Validation I ran:

git diff --check origin/main...HEAD -- agent_relationships.py bounties/issue-2285/src/memory_routes.py bridge/bridge_api.py contributor_registry.py node/machine_passport_api.py payout_ledger.py
# failed: trailing whitespace in agent_relationships.py, contributor_registry.py, and node/machine_passport_api.py

python3 -B -m py_compile agent_relationships.py bounties/issue-2285/src/memory_routes.py bridge/bridge_api.py contributor_registry.py node/machine_passport_api.py payout_ledger.py
# py_compile_exit=0

# focused Flask probes with ADMIN_KEY=sekrit
contributor_registry GET /approve/alice => 401
contributor_registry GET /approve/alice?admin_key=sekrit => 302
contributor_registry status after query-auth approve => approved
payout_ledger POST /api/ledger no header => 401
payout_ledger POST /api/ledger?admin_key=sekrit => 201
payout_ledger POST /api/ledger X-Admin-Key => 201
payout_ledger rows inserted => 2
contributor_registry.py query_param_admin_key=True hmac_compare_digest_present=False
payout_ledger.py query_param_admin_key=True hmac_compare_digest_present=False
bounties/issue-2285/src/memory_routes.py query_param_admin_key=True hmac_compare_digest_present=False

The PR is trying to secure admin mutations, but the new decorators in contributor_registry.py, payout_ledger.py, and bounties/issue-2285/src/memory_routes.py still accept ?admin_key=. That puts the admin secret in URLs, access logs, browser history, and referrers; the probe above shows it is enough to approve a contributor and create payout ledger rows without any X-Admin-Key header.

Those same decorators also use plain != rather than hmac.compare_digest, so the timing-safety fix is only applied to bridge/bridge_api.py and agent_relationships.py, not to the new admin gates added elsewhere.

Requested changes:

1. Drop the query-string admin_key fallback for mutating/admin routes.
2. Use hmac.compare_digest for all admin-key comparisons, not just the bridge/relationship paths.
3. Add regression tests that prove ?admin_key=sekrit is rejected while X-Admin-Key: sekrit succeeds.
4. Clean up the git diff --check whitespace failures.

[himanalot]

Requesting changes.

The bridge compare_digest change is fine, but this PR also adds several new admin_required decorators that accept the admin secret from request.args.get("admin_key") and compare it with req_key != ADMIN_KEY (contributor_registry.py, payout_ledger.py, and bounties/issue-2285/src/memory_routes.py). That puts admin secrets in URLs, where they are routinely captured in access logs, browser history, analytics, and referrers, and the newly added comparisons are not timing-safe.

Please make these new admin checks header-only and use a constant-time comparison, or remove the unrelated endpoint changes from this PR and keep the patch scoped to the bridge timing fix plus the agent relationship mutations.

[Scottcjn]

Paid 10 RTC of 40 RTC cluster (PRs #5011 #5012 #5014 #5080).

tx_hash: 0ff9c8d19252e2edca197859e66845ad | pending #1510 | confirms in 24h

Closing as merge-conflict. All 4 PRs add overlapping admin_required decorators on the same files (memory_routes.py + machine_passport_api.py), so they conflict with each other and main has moved. The security direction is correct (auth-hardening unauthenticated Flask endpoints) and the diffs are clean — paying for the audit work even though we can't cleanly merge the 4-way overlap.

To unblock: rebase a single consolidated PR off latest main with all 4 hardenings in one diff, and we'll merge it as a follow-on (no additional bounty — the work is already paid).

— triage 2026-05-14

[HCIE2054]

LGTM! Thanks for contributing!