{"abstract":"Untrusted peer cannot supply forwarding identity.","category":"Proxy forwarding","checks":4,"contract":"Bounded offline decision model: untrusted peer cannot supply forwarding identity. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-untrusted-peer-cannot-supply-forwarding-identity","failed_approach":"The attempted repair uses `[peer]` and still violates a separate fixture.","family":"xh-untrusted-peer-cannot-supply-forwarding-identity","id":"FA-6971","implementations":{"attempt":{"sha256":"ac3377d9993b7942cc0cc9c75dfbbdc7802e270b9774d53cd9d61ed119fa32f5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(peer, chain, trusted):\n    return [peer]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('p', ['c'], ['p']), ['c'])\", \"check('fixture 2', solve('p', ['spoof'], []), ['p'])\", \"check('fixture 3', solve('p', [], []), ['p'])\", \"check('fixture 4', solve('p', [], ['p']), [])\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"199fdd0271a803359fd483736b987afcf60642aae956c672e041cee9b27c2d33","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(peer, chain, trusted):\n    return chain\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('p', ['c'], ['p']), ['c'])\", \"check('fixture 2', solve('p', ['spoof'], []), ['p'])\", \"check('fixture 3', solve('p', [], []), ['p'])\", \"check('fixture 4', solve('p', [], ['p']), [])\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"4f00bd9150f57585e04ae597032bbd796a7bcfecac9c748df96478968a2427c8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(peer, chain, trusted):\n    return chain if peer in trusted else [peer]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('p', ['c'], ['p']), ['c'])\", \"check('fixture 2', solve('p', ['spoof'], []), ['p'])\", \"check('fixture 3', solve('p', [], []), ['p'])\", \"check('fixture 4', solve('p', [], ['p']), [])\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xh-untrusted-peer-cannot-supply-forwarding-identity","generated_at":"2026-09-29T14:38:07.154470+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic proxy forwarding model isolates the untrusted-peer-cannot-supply-forwarding-identity policy at a network component boundary.","repair":"Apply the explicit untrusted-peer-cannot-supply-forwarding-identity contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `chain` for the untrusted-peer-cannot-supply-forwarding-identity decision.","sha256":"d1e7e43ebf393376efa7a391756effec67d38c1dd133487ec467d18057a7c01c","title":"Untrusted peer cannot supply forwarding identity · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":34.795,"exit_code":1,"observations":[{"actual":["p"],"check":"fixture 2","expected":["p"],"passed":true},{"actual":["p"],"check":"fixture 3","expected":["p"],"passed":true},{"actual":["p"],"check":"fixture 4","expected":[],"passed":false},{"actual":["p"],"check":"fixture 1","expected":["c"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [\"p\"], \"expected\": [\"p\"], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [\"p\"], \"expected\": [\"p\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"p\"], \"expected\": [], \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": [\"p\"], \"expected\": [\"c\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":33.399,"exit_code":1,"observations":[{"actual":["spoof"],"check":"fixture 2","expected":["p"],"passed":false},{"actual":[],"check":"fixture 3","expected":["p"],"passed":false},{"actual":[],"check":"fixture 4","expected":[],"passed":true},{"actual":["c"],"check":"fixture 1","expected":["c"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [\"spoof\"], \"expected\": [\"p\"], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [\"p\"], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": [\"c\"], \"expected\": [\"c\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":36.187,"exit_code":0,"observations":[{"actual":["p"],"check":"fixture 2","expected":["p"],"passed":true},{"actual":["p"],"check":"fixture 3","expected":["p"],"passed":true},{"actual":[],"check":"fixture 4","expected":[],"passed":true},{"actual":["c"],"check":"fixture 1","expected":["c"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [\"p\"], \"expected\": [\"p\"], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [\"p\"], \"expected\": [\"p\"], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": [\"c\"], \"expected\": [\"c\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}