The CSRF middleware answered a refused login or generator form with the
library's bare text, such as "Forbidden - origin invalid". It now answers
403 with a page that names the cause and what to do, and logs a warning
with the request ID and the library's reason. A page opened over plain
HTTP with debug off and a form from another host both fail the origin
check; the page tells them apart by the host in the Origin or Referer
header.
Model: opus-5-5
seal.DeriveKeys derives the session hash and block keys, the encrypted URL
key and the CSRF key from the signing key, with their salts declared beside
it, and returns them as one seal.Keys. internal/providers calls it once at
startup and provides the value to the fx graph. The session manager, the
encrypted URL generator and the CSRF protection each take their own key.
session.NewManager, encurl.NewGenerator, newCSRFProtect and handlers.New
return no error, as nothing in them can fail now. Each key is derived as
before, with seal.DeriveKey and the same salt. The signing key itself stays
the HMAC key of signed URLs and the login password. README.md says under
signing_key what it protects.
Model: opus-5-5
The http.Server now sets ReadHeaderTimeout (10s), which bounds the slow header dribble that ReadTimeout alone does not, and IdleTimeout (120s), which bounds keep-alive reuse. Server construction moved into a small helper so a test can assert the timeouts without binding a listener.
POST / and POST /generate bodies are capped at 1 MiB and an oversized body returns 413.
What a reader would trip over: the CSRF library reads its token from the form and swallows a parse error, so a cap applied only inside it would surface as 403. The body limit therefore parses the form under the cap before the CSRF check; the parsed form is reused afterwards. A test covers an oversized body that carries a valid token.
Judgement call: WriteTimeout stays at 60s; it also bounds how long a large image may take to send over a slow link.
Model: opus-4-8 (implementation, review); fable-5-1 (landing message)