test: allowlist dead-entry + FastAPI dependant-contract guards (PER-15249)

[dshoen619]

Closes the two remaining gaps for PER-15249 (Route auth-coverage regression guard, block-merge).

Context: most of PER-15249 already shipped

The route-auth regression guard the issue asks for landed with PER-15245 (#321) as horizon/tests/test_route_auth_audit.py: it builds the app the production way (MockPermitPDP → _configure_api_routes), walks app.routes, fails any APIRoute lacking a recognized gate (enforce_pdp_token, enforce_pdp_control_key, JWTAuthenticator, require_listener_token — nested closures flattened via get_flat_dependant), flags un-gateable mounts, and single-sources the allowlist from horizon.authentication.PUBLIC_ROUTE_PATHS. The pytests CI job that runs it is already a required status check on main (repo ruleset 11170517), so the block-merge requirement is met. The issue's "middleware invisible to route.dependant" concern is moot: OPAL trigger routes are gated in place by _gate_opal_trigger_routes in horizon/pdp.py, not via middleware.

What this PR adds

Two tests, one file, no production-code changes:

• test_allowlist_has_no_dead_entries — every PUBLIC_ROUTE_PATHS entry must match a mounted route, so the allowlist can't rot into a pre-authorized hole for a future route to fall into. /scalar is the one documented exception (registered in PermitPDP.__init__ after _configure_api_routes, so it's invisible to the audit-built app); the test also fails if that exemption ever goes stale.
• test_router_level_dependencies_surface_in_flat_dependant — the issue's "codex-required" empirical proof, now a permanent contract test: include_router(dependencies=[...]) deps and nested Depends() both surface via get_flat_dependant on the resolved FastAPI (0.125.0; pin >=0.115.6,<1), exercised through the audit's own _route_auth_gates helper, with diagnostics for a future FastAPI bump. Uses the repo's Annotated[..., Depends(...)] convention to stay B008-clean.

Verification

• test_route_auth_audit.py: 8/8 passed (was 6)
• Full horizon/tests/: 120/120 passed (parity with the pytests job)
• ruff check clean, ruff format --check clean
• Red-before-green confirmed out-of-band: replaying the audit logic at pre-fix 02f7655 flags exactly POST /policy-updater/trigger, POST /data-updater/trigger, POST /kong — the three routes PER-15244/15245 gated.
• Dead-entry test has teeth: injecting a bogus allowlist entry makes it fail.

🤖 Generated with Claude Code

[linear-code]

PER-15249

[github-actions]

🔍 Vulnerabilities of permitio/pdp-v2:next

📦 Image Reference permitio/pdp-v2:next

digest	sha256:fc12e880ea91ec43584dfc522cbe40eda21000f8ced00de9ae1ccf4d673413f5
vulnerabilities
platform	linux/amd64
size	132 MB
packages	248

📦 Base Image python:3.13-alpine3.23

also known as	3.13.14-alpine3.23 e0e75f8d10947da66ae425727cad4e480c65f32018367f4006f9eba40c48cd5c
digest	sha256:72c39ab9dbf2227aa91ec2246e6492260ee2530c36bdf37b208394b42d757b60
vulnerabilities

starlette 0.50.0 (pypi) pkg:pypi/starlette@0.50.0 Allocation of Resources Without Limits or Throttling Affected range >=0.4.1 <1.3.1 Fixed version 1.3.1 CVSS Score 7.5 CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H EPSS Score 0.397% EPSS Percentile 33rd percentile Description Summary request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. Details request.form() dispatches to a different parser depending on the Content-Type. For multipart/form-data the max_files, max_fields, and max_part_size limits are forwarded to the parser, but for application/x-www-form-urlencoded the parser is constructed without them. It has no max_fields or max_part_size parameter to receive them, and it appends every field with no count check and accumulates each field's name and value with no size check. The configured limits are therefore both unreachable and unenforced for url-encoded bodies. Because the url-encoded parser does its work synchronously between stream reads, the two attack shapes have different effects: Field count drives CPU and event-loop blocking. A body of ~1,000,000 fields (a sub-10MB payload such as f0=v&f1=v&...) blocks the worker's event loop for several seconds while parsing, during which the worker serves no other request. Field size drives memory. A single large field value (e.g. a 50MB value) is buffered in full to build the FormData, forcing memory allocation proportional to the request body. The equivalent multipart/form-data request is correctly rejected with 400 Too many fields / 400 Field exceeded maximum size. Impact This Denial of service (DoS) vulnerability affects all applications built with Starlette (or FastAPI) that call request.form() on application/x-www-form-urlencoded requests. A single request with a very large number of fields blocks the event loop for several seconds, and a single request with a very large field forces unbounded memory allocation; in either case, parallel requests can render the service unusable. A reverse proxy that enforces a request body size limit reduces but does not eliminate the exposure, since a sub-10MB body is already enough to block the event loop. Mitigation Upgrade to a patched version, which forwards max_fields and max_part_size to the url-encoded parser and enforces them while parsing, raising before the oversized field or excess fields are accumulated. The defaults match multipart/form-data (max_fields=1000, max_part_size=1MB) and can be customized via request.form(max_fields=..., max_part_size=...). Server-Side Request Forgery (SSRF) Affected range <1.1.0 Fixed version 1.1.0 CVSS Score 7.5 CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N EPSS Score 0.368% EPSS Percentile 30th percentile Description Summary When serving static files on Windows, StaticFiles resolves the requested path with os.path.realpath. If a UNC path (such as \\attacker.com\share) reaches the resolver, realpath causes the process to open a connection to the remote host over SMB (port 445). This is a server-side request forgery (SSRF) that leaks the service account's NTLMv2 credentials to the attacker-controlled host, which can then be cracked offline or relayed to other hosts. Details StaticFiles.lookup_path() joins the requested path onto the served directory and calls os.path.realpath on the result before checking containment with os.path.commonpath. On Windows, a UNC path is absolute, so os.path.join discards the served directory and realpath resolves the bare UNC path, triggering the outbound SMB connection and NTLM authentication before the containment check rejects the path. The HTTP response is a benign 404, but the credential disclosure has already happened. POSIX systems are not affected. This only affects the default configuration (follow_symlink=False), which uses os.path.realpath. The follow_symlink=True branch uses os.path.abspath, which performs no I/O. Impact Applications running on Windows that serve files with StaticFiles (directly, or via a framework built on Starlette such as FastAPI) in the default configuration are affected. StaticFiles is typically unauthenticated, so any client can trigger the SMB connection and leak the service account's NTLMv2 hash. A secondary impact is discovering internal hosts reachable over SMB by timing responses for valid versus invalid addresses. Mitigation Applications not running on Windows are not affected. On Windows, serving static files through a dedicated web server (such as nginx or IIS) instead of StaticFiles avoids the issue. Blocking outbound SMB (port 445) from the application host prevents the credential disclosure even if a UNC path is resolved. Improper Validation of Unsafe Equivalence in Input Affected range <=1.0.0 Fixed version 1.0.1 CVSS Score 6.5 CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N EPSS Score 1.839% EPSS Percentile 77th percentile Description Summary In affected versions, the HTTP Host request header was not validated before being used to reconstruct request.url. Because the routing algorithm relies on the raw HTTP path while request.url is rebuilt from the Host header, a malformed header could make request.url.path differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on request.url (rather than the raw scope path) could therefore be bypassed. Details When a client requests http://example.com/foo, it sends: GET /foo HTTP/1.1 Host: example.com Affected versions reconstructed the URL by concatenating http://{host}{path} and re-parsing the result. The Host value is only valid as a uri-host [ ":" port ] per RFC 9112 §3.2, where uri-host follows the restricted host grammar of RFC 3986 §3.2.2. When it contains characters outside that grammar - notably /, ?, or # - those characters move the path/query/fragment boundaries during re-parsing, so the parsed request.url.path no longer matches the path the server actually received. For example: GET /foo HTTP/1.1 Host: example.com/abc?bar= reconstructs to http://example.com/abc?bar=/foo, whose parsed path is /abc - even though routing used the real path /foo. The router still dispatches to /foo and the endpoint executes, but any middleware or code that reads request.url.path sees /abc, so path-based authorization checks can be bypassed. Impact Any application running an affected version that relies on request.url (or request.url.path) for security-sensitive decisions is affected. The most common case is middleware that gates access to certain path prefixes based on request.url.path. Deployments fronted by a proxy or load balancer are mitigated only if that proxy rejects or normalizes the malformed Host header before forwarding and the application does not trust attacker-controlled host headers (e.g. X-Forwarded-Host) elsewhere. Mitigation Upgrade to a patched version, which validates the Host header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing request.url and falls back to scope["server"] for malformed values. Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') Affected range <1.1.0 Fixed version 1.1.0 CVSS Score 5.3 CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N EPSS Score 0.213% EPSS Percentile 12th percentile Description Summary When dispatching a request, HTTPEndpoint selects the handler by lowercasing the HTTP method and looking it up as an attribute with getattr, without restricting the lookup to a known set of HTTP verbs. When an HTTPEndpoint subclass is registered through Route(...) without an explicit methods= argument, the route does not constrain the method and every method reaches the endpoint. If a non-standard HTTP method whose lowercased name matches an attribute on the endpoint subclass reaches the endpoint, that attribute is invoked as if it were a request handler. An attacker can use this to reach methods that were never meant to be HTTP handlers, such as internal helpers, without the authorization checks applied by the intended public handler. Details HTTPEndpoint uses the client-supplied method name to resolve an instance attribute, without validating it against the set of HTTP verbs the endpoint supports. A method such as _DO_DELETE therefore resolves an attribute like _do_delete and invokes it. Non-standard methods are valid RFC 9110 token methods, so an endpoint must not treat the method name as a trusted attribute selector. Impact An application is affected when all of the following hold: It defines an HTTPEndpoint subclass and registers it via Route(...) without an explicit methods= argument. The subclass defines additional methods whose names match a non-standard HTTP-method token shape and that accept a single request argument and return a response. This also affects frameworks built on Starlette, like FastAPI. Mitigation Register HTTPEndpoint subclasses with an explicit methods= argument on the Route, listing only the HTTP verbs the endpoint supports. The route then rejects any other method with 405 Method Not Allowed before it reaches the endpoint, so non-standard methods cannot resolve an attribute. Improper Input Validation Affected range <1.3.0 Fixed version 1.3.0 CVSS Score 3.7 CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N EPSS Score 0.187% EPSS Percentile 9th percentile Description Summary In affected versions, the HTTP request path is not validated before being used to reconstruct request.url. Because request.url is rebuilt by concatenating {scheme}://{host}{path} and re-parsing the result, a path that does not begin with / (for example @<!-- -->google.com) moves the authority boundary during re-parsing, so request.url.hostname and request.url.netloc become attacker-controlled. Code that reads request.url.hostname (rather than the Host header or scope) can therefore be misled into trusting an attacker-supplied host. Details When a client requests a path that does not start with /: GET @<!-- -->google.com HTTP/1.1 Host: localhost affected versions reconstruct the URL as http://localhost@<!-- -->google.com. Per RFC 3986 §3.2.1, the substring before @ in the authority is userinfo, so re-parsing yields username = "localhost" and hostname = "google.com", with an empty path: request.url == "http://localhost@<!-- -->google.com" request.url.hostname == "google.com" request.url.path == "" The root cause is that the path is concatenated directly after the host without a separating /, and without validating that it begins with one. Only the Host header was validated when constructing request.url; the path was not. This requires an ASGI server that forwards a request-target lacking a leading / into scope["path"]. Impact Any application running an affected version that uses request.url, request.url.netloc, or request.url.hostname for a security-sensitive decision (host-based authorization, redirect/callback base, SSRF target, cache key, audit log) may be affected, when no fronting proxy or load balancer rejects the malformed request-target first. Note that this is less exploitable than GHSA-86qp-5c8j-p5mr: there, the poison is carried in the Host header, so the real path still routes to a valid endpoint while request.url.path lies. Here, the poison must be carried in the path itself, and that path (@<!-- -->google.com) does not match any registered route, so routing returns 404 and no endpoint handler runs. The exposure is limited to code that reads request.url before routing - notably middleware - or in 404/exception handlers. Mitigation Upgrade to a patched version, which prevents the request path from crossing into the URL authority. The request above instead yields http://localhost/@<!-- -->google.com with request.url.hostname == "localhost".

ddtrace 3.19.8 (pypi) pkg:pypi/ddtrace@3.19.8 Uncontrolled Resource Consumption Affected range <4.8.2 Fixed version 4.8.2 CVSS Score 7.5 CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H EPSS Score 0.441% EPSS Percentile 36th percentile Description Impact Datadog tracing libraries that implement W3C baggage propagation parse incoming baggage HTTP headers without enforcing item-count or byte-size limits on the extract path. The DD_TRACE_BAGGAGE_MAX_ITEMS (default 64) and DD_TRACE_BAGGAGE_MAX_BYTES (default 8192) limits were applied only to baggage injection, not extraction. A remote, unauthenticated attacker can send a request whose baggage header contains an arbitrarily large number of comma-separated key-value pairs (or a single very large value). The tracer allocates a hash-map entry for each pair on every request, causing unbounded CPU and memory consumption and enabling a remote Denial of Service against any HTTP service that has the baggage propagation style enabled. The baggage propagation style is enabled by default in most affected tracers, so any internet-facing service that has been instrumented with an affected tracer version is exposed unless the propagation style has been explicitly narrowed. Patches This is resolved in version 4.8.2 and later of the dd-trace-py library Workarounds If users cannot upgrade immediately: Disable baggage extraction by removing baggage from DD_TRACE_PROPAGATION_STYLE (or DD_TRACE_PROPAGATION_STYLE_EXTRACT if set independently). Cap the maximum HTTP request header size at an upstream proxy or web server (for example, Apache LimitRequestFieldSize, Nginx large_client_header_buffers, Envoy max_request_headers_kb). Resources Related upstream advisories: opentelemetry-go GHSA-mh2q-q3fh-2475 opentelemetry-dotnet GHSA-g94r-2vxg-569j

busybox 1.37.0-r30 (apk) pkg:apk/alpine/busybox@1.37.0-r30?os_name=alpine&os_version=3.23 Affected range <=1.37.0-r30 Fixed version Not Fixed EPSS Score 0.285% EPSS Percentile 21st percentile Description

golang.org/x/crypto 0.53.0 (golang) pkg:golang/golang.org/x/crypto@0.53.0 Affected range >=0 Fixed version Not Fixed Description The golang.org/x/crypto/openpgp package is unsafe by design, has numerous known security issues, is not maintained, and should not be used. If you are required to interoperate with OpenPGP systems and need a maintained package, consider github.com/ProtonMail/go-crypto/openpgp which is a maintained fork that aims to be a drop-in replacement for this package.

[github-actions]

🔍 Vulnerabilities of permitio/pdp-v2:next

📦 Image Reference permitio/pdp-v2:next

digest	sha256:fc12e880ea91ec43584dfc522cbe40eda21000f8ced00de9ae1ccf4d673413f5
vulnerabilities
platform	linux/amd64
size	132 MB
packages	248

📦 Base Image python:3.13-alpine3.23

also known as	3.13.14-alpine3.23 e0e75f8d10947da66ae425727cad4e480c65f32018367f4006f9eba40c48cd5c
digest	sha256:72c39ab9dbf2227aa91ec2246e6492260ee2530c36bdf37b208394b42d757b60
vulnerabilities

[Copilot]

Pull request overview

This PR strengthens the existing “fail-closed” route-auth audit by adding two contract-style tests that (1) prevent the public-route allowlist from accumulating dead entries and (2) lock in the FastAPI dependency-flattening behavior the audit relies on.

Changes:

• Add a test to ensure every PUBLIC_ROUTE_PATHS entry corresponds to an actually-mounted route (with a single, checked exemption for /scalar).
• Add a contract test proving router-level include_router(..., dependencies=[...]) dependencies and nested Depends() dependencies surface via get_flat_dependant.
• Update imports/constants in the audit test module to support the new tests.

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