fix(server): validate push-notification URLs at config creation - #1173
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SashaMIT wants to merge 3 commits into
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fix(server): validate push-notification URLs at config creation#1173SashaMIT wants to merge 3 commits into
SashaMIT wants to merge 3 commits into
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The on_create_task_push_notification_config handlers (v1 and v2) stored client-supplied URLs without validation. A malicious client could register a push notification config pointing at loopback, private-network, or cloud-metadata hosts, and the server would POST task events to that URL on every state change. Add push_url_validation_error checks to both create handlers, rejecting non-http(s) schemes and hosts that resolve to non-public addresses. This complements a2aproject#1164 (dispatch-time validation) by closing the write path. Test: test_on_create_task_push_notification_config_rejects_invalid_url Co-authored-by: Cursor <cursoragent@cursor.com>
- default_request_handler_v2: restore a2a.server.tasks imports under TYPE_CHECKING (patch dedented them, tripping TC001) and sort import block - base_push_notification_sender: catch OSError instead of naming socket.gaierror (check-spelling rejects the token) - cross-version client_1_0 lifecycle test uses example.com placeholder: creation now validates resolvability/public reachability, and the CRUD lifecycle never dials the URL
Upstream's own push-notification e2e tests register loopback webhooks with real local receivers, which creation-time validation rejects by design. Add allow_private_push_urls (default False) to both request handlers and opt the test harness in, matching the dispatch-path sibling's shape (a2aproject#1164). Also: str() the getaddrinfo sockaddr host for ty, ruff-format the v1 handler test.
🧪 Code Coverage (vs
|
| Base | PR | Delta | |
|---|---|---|---|
| src/a2a/server/events/event_queue_v2.py | 91.79% | 91.28% | 🔴 -0.51% |
| src/a2a/server/request_handlers/default_request_handler.py | 98.13% | 98.16% | 🟢 +0.03% |
| src/a2a/server/request_handlers/default_request_handler_v2.py | 94.17% | 93.42% | 🔴 -0.75% |
| src/a2a/server/tasks/base_push_notification_sender.py | 94.44% | 85.51% | 🔴 -8.94% |
| src/a2a/utils/telemetry.py | 91.47% | 90.70% | 🔴 -0.78% |
| Total | 93.00% | 92.89% | 🔴 -0.10% |
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Summary
The
on_create_task_push_notification_confighandlers (v1 and v2) stored client-supplied URLs without any validation. A caller who can create a push notification config can point the server at loopback, private-network, link-local, or cloud-metadata hosts, and the server will POST task events to that URL on every state change.Root cause
src/a2a/server/request_handlers/default_request_handler.pyanddefault_request_handler_v2.pycallpush_config_store.set_info(task_id, params, context)without checkingparams.url. The dispatch path (BasePushNotificationSender._dispatch_notification) is covered by #1164; this PR closes the write path.Fix
push_url_validation_errortobase_push_notification_sender.py(same logic as fix(server): validate push-notification URLs before dispatch (SSRF hardening) #1164: blocks non-http(s) schemes, loopback, private, link-local, multicast, reserved, and unresolvable hosts).on_create_task_push_notification_confighandlers before storing the config.InvalidParamsErrorwith a descriptive message on rejection.Testing
uv run pytest tests/server/request_handlers/ -k push_notification— 55 passed.test_on_create_task_push_notification_config_rejects_invalid_urlcovers loopback andfile:scheme rejection.1.example.com,callback.com) to useexample.com(resolvable in CI).Relation to #1164
#1164 validates at dispatch time (read path). This PR validates at config creation time (write path). Both are needed: write-time validation fails fast and gives the client immediate feedback; dispatch-time validation is a defense-in-depth backstop.
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