FA-29071 / HTTP redirects / Open access

Build public redirect origins from explicitly trusted proxy metadata: direct authority port preserved · case 01

Build public redirect origins from explicitly trusted proxy metadata: the direct authority port preserved branch emits an incorrect decision.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The direct-authority-port-preserved decision uses "direct_host.split(':')[0]"; this violates the stipulated controller policy.

THE FAILURE

The direct-authority-port-preserved decision uses "direct_host.split(':')[0]"; this violates the stipulated controller policy.

Unsuccessful approach: The partial repair uses 'chain[0] if chain else direct_host' and still fails an explicit boundary or control.

Case contract

Build public redirect origins from explicitly trusted proxy metadata. The explicit fixture inputs and outputs define a bounded offline policy; request identity must accompany the decision.

Why this case matters

Models a redirect controller decision before following a target or exposing a redirect result.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from urllib.parse import urlsplit, unquote, quote
import posixpath
import re
N = 1
observations = []
def solve(request, trusted, chain, proto, direct_host, direct_scheme, prefix):
    return {'request': request, 'decision': [chain[0] if trusted and chain else direct_host, proto.lower() if trusted and proto else direct_scheme, chain, bool(chain), '/' + prefix.lstrip('/') if prefix else '', prefix if trusted else '', direct_host.split(':')[0], prefix.rstrip('/')+'/' if prefix else '/', not proto or proto.lower() in ('http','https'), 'forwarded' if trusted and chain else 'direct']} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', True, ['client.test', 'edge.test'], 'https', 'internal:8080', 'http', '/app'), {'request': '/requests/' + str(N) + '/0', 'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'internal:8080', '/app/', True, 'forwarded']})
check('fixture 2', solve('/requests/' + str(N) + '/1', False, ['attacker.test'], 'https', 'public.test', 'http', '/'), {'request': '/requests/' + str(N) + '/1', 'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'public.test', '/', True, 'direct']})
check('fixture 3', solve('/requests/' + str(N) + '/2', True, [], '', 'fallback.test', 'https', ''), {'request': '/requests/' + str(N) + '/2', 'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct']})
check('fixture 4', solve('/requests/' + str(N) + '/3', True, ['one.test', 'two.test', 'three.test'], 'http', 'internal', 'https', '/v2/'), {'request': '/requests/' + str(N) + '/3', 'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'internal', '/v2/', True, 'forwarded']})
check('fixture 5', solve('/requests/' + str(N) + '/4', True, ['public.test'], 'HTTPS', 'internal', 'http', '//evil.test'), {'request': '/requests/' + str(N) + '/4', 'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'internal', '//evil.test/', True, 'forwarded']})
check('fixture 6', solve('/requests/' + str(N) + '/5', False, [], 'http', 'actual.test', 'https', '/x'), {'request': '/requests/' + str(N) + '/5', 'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct']})
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`{'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'internal', '/app/', True, 'forwarded'], 'request': '/requests/1/0'}`	`{'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'internal:8080', '/app/', True, 'forwarded'], 'request': '/requests/1/0'}`	Failed
fixture 2	`{'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'public.test', '/', True, 'direct'], 'request': '/requests/1/1'}`	`{'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'public.test', '/', True, 'direct'], 'request': '/requests/1/1'}`	Passed
fixture 3	`{'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct'], 'request': '/requests/1/2'}`	`{'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct'], 'request': '/requests/1/2'}`	Passed
fixture 4	`{'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'internal', '/v2/', True, 'forwarded'], 'request': '/requests/1/3'}`	`{'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'internal', '/v2/', True, 'forwarded'], 'request': '/requests/1/3'}`	Passed
fixture 5	`{'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'internal', '//evil.test/', True, 'forwarded'], 'request': '/requests/1/4'}`	`{'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'internal', '//evil.test/', True, 'forwarded'], 'request': '/requests/1/4'}`	Passed
fixture 6	`{'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct'], 'request': '/requests/1/5'}`	`{'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct'], 'request': '/requests/1/5'}`	Passed

SHA-256 / dde03bd681e2868a2a04af842b64d50355df764a3e44d6c2bfab74307c90309f

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from urllib.parse import urlsplit, unquote, quote
import posixpath
import re
N = 1
observations = []
def solve(request, trusted, chain, proto, direct_host, direct_scheme, prefix):
    return {'request': request, 'decision': [chain[0] if trusted and chain else direct_host, proto.lower() if trusted and proto else direct_scheme, chain, bool(chain), '/' + prefix.lstrip('/') if prefix else '', prefix if trusted else '', chain[0] if chain else direct_host, prefix.rstrip('/')+'/' if prefix else '/', not proto or proto.lower() in ('http','https'), 'forwarded' if trusted and chain else 'direct']} 
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve('/requests/' + str(N) + '/0', True, ['client.test', 'edge.test'], 'https', 'internal:8080', 'http', '/app'), {'request': '/requests/' + str(N) + '/0', 'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'internal:8080', '/app/', True, 'forwarded']})
check('fixture 2', solve('/requests/' + str(N) + '/1', False, ['attacker.test'], 'https', 'public.test', 'http', '/'), {'request': '/requests/' + str(N) + '/1', 'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'public.test', '/', True, 'direct']})
check('fixture 3', solve('/requests/' + str(N) + '/2', True, [], '', 'fallback.test', 'https', ''), {'request': '/requests/' + str(N) + '/2', 'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct']})
check('fixture 4', solve('/requests/' + str(N) + '/3', True, ['one.test', 'two.test', 'three.test'], 'http', 'internal', 'https', '/v2/'), {'request': '/requests/' + str(N) + '/3', 'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'internal', '/v2/', True, 'forwarded']})
check('fixture 5', solve('/requests/' + str(N) + '/4', True, ['public.test'], 'HTTPS', 'internal', 'http', '//evil.test'), {'request': '/requests/' + str(N) + '/4', 'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'internal', '//evil.test/', True, 'forwarded']})
check('fixture 6', solve('/requests/' + str(N) + '/5', False, [], 'http', 'actual.test', 'https', '/x'), {'request': '/requests/' + str(N) + '/5', 'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct']})
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`{'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'client.test', '/app/', True, 'forwarded'], 'request': '/requests/1/0'}`	`{'decision': ['client.test', 'https', ['client.test', 'edge.test'], True, '/app', '/app', 'internal:8080', '/app/', True, 'forwarded'], 'request': '/requests/1/0'}`	Failed
fixture 2	`{'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'attacker.test', '/', True, 'direct'], 'request': '/requests/1/1'}`	`{'decision': ['public.test', 'http', ['attacker.test'], True, '/', '', 'public.test', '/', True, 'direct'], 'request': '/requests/1/1'}`	Failed
fixture 3	`{'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct'], 'request': '/requests/1/2'}`	`{'decision': ['fallback.test', 'https', [], False, '', '', 'fallback.test', '/', True, 'direct'], 'request': '/requests/1/2'}`	Passed
fixture 4	`{'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'one.test', '/v2/', True, 'forwarded'], 'request': '/requests/1/3'}`	`{'decision': ['one.test', 'http', ['one.test', 'two.test', 'three.test'], True, '/v2/', '/v2/', 'internal', '/v2/', True, 'forwarded'], 'request': '/requests/1/3'}`	Failed
fixture 5	`{'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'public.test', '//evil.test/', True, 'forwarded'], 'request': '/requests/1/4'}`	`{'decision': ['public.test', 'https', ['public.test'], True, '/evil.test', '//evil.test', 'internal', '//evil.test/', True, 'forwarded'], 'request': '/requests/1/4'}`	Failed
fixture 6	`{'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct'], 'request': '/requests/1/5'}`	`{'decision': ['actual.test', 'https', [], False, '/x', '', 'actual.test', '/x/', True, 'direct'], 'request': '/requests/1/5'}`	Passed

SHA-256 / 1de707614ec550dec5d6265b83646ae8e3fa788f4d4d8e0effc726063e0233b5

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Stipulated offline redirect policy, not a complete HTTP, browser, URL, cache, or security implementation. Numbered variants vary request correlation identity. 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:41:39.760866+00:00.

Case digest / 5a66dc64ecbf2ea76fd1df5d16a2dbf9c04eb186990333e0cf261d6b03cd9021