Bound approval transport and refuse redirects and proxies

Assistant: codex
Assistant-Model: gpt-6.1-sol
Assistant-Session: 01a126e1-76f8-7643-8cf3-e93336539ade

approval_engine/http_transport.py

@@ -0,0 +1,71 @@
+"""Isolated fixed-origin HTTP transport. No credentials in argv or diagnostics.
+
+Invoked by the SDK through a bounded subprocess, not as an application command.
+Isolation allows the parent to terminate DNS, reads and exceptional close without
+signals in an application's main thread or mandatory multiprocessing main guards.
+"""
+
+import json
+import sys
+from urllib.error import HTTPError
+from urllib.request import HTTPRedirectHandler, ProxyHandler, Request, build_opener
+
+MAX_BODY = 256 * 1024
+
+
+class NoRedirect(HTTPRedirectHandler):
+    def redirect_request(self, req, fp, code, msg, headers, newurl):
+        raise HTTPError(req.full_url, code, "redirect refused", headers, fp)
+
+
+def fetch(data):
+    request = Request(data["url"], data=data["body"].encode("utf-8") if data["body"] is not None else None,
+                      method=data["method"], headers={"Authorization": "Bearer " + data["token"],
+                      "Content-Type": "application/json", "Accept": "application/json"})
+    opener = build_opener(ProxyHandler({}), NoRedirect())
+    response = None
+    try:
+        response = opener.open(request, timeout=data["timeout"])
+        if response.geturl() != data["url"] or response.getcode() != 200:
+            return {"error": "status", "status": response.getcode()}
+        types = response.headers.get_all("Content-Type", [])
+        if len(types) != 1 or response.headers.get_content_type() != "application/json":
+            return {"error": "content"}
+        charset = response.headers.get_content_charset()
+        if charset not in (None, "utf-8") or response.headers.get("Content-Encoding", "identity").lower() != "identity":
+            return {"error": "content"}
+        lengths = response.headers.get_all("Content-Length", [])
+        if len(lengths) > 1 or (lengths and (not lengths[0].isdigit() or int(lengths[0]) > MAX_BODY)):
+            return {"error": "content"}
+        raw = response.read(MAX_BODY + 1)
+        if len(raw) > MAX_BODY or (lengths and len(raw) != int(lengths[0])):
+            return {"error": "content"}
+        return {"body": raw.decode("utf-8")}
+    except HTTPError as exc:
+        # Never read a refused/redirect/error body; even close is parent-bounded.
+        try:
+            exc.close()
+        except Exception:
+            pass
+        return {"error": "status", "status": int(exc.code)}
+    except Exception:
+        return {"error": "unavailable"}
+    finally:
+        if response is not None:
+            try:
+                response.close()
+            except Exception:
+                pass
+
+
+def main():
+    try:
+        data = json.loads(sys.stdin.buffer.read(MAX_BODY + 1))
+        result = fetch(data)
+    except Exception:
+        result = {"error": "unavailable"}
+    sys.stdout.write(json.dumps(result, allow_nan=False))
+
+
+if __name__ == "__main__":
+    main()