Three things a licence audit turned up. None of them is a conflict --
every one of the 182 installed packages is permissive, and the relicence
was within the copyright holder's gift -- but all three are ways the
AGPL fails to stick.
The offer was hard-coded to this repository. Section 13 asks whoever
runs a modified version to offer *that* version's source, so every
deployment with a patch in it was pointing at the wrong tree, and would
have gone on doing so unless its operator noticed and edited the About
page. SOURCE_URL now sets it, alongside APP_NAME, and both the sign-in
page and About read it.
The offer was also only visible after signing in. Whoever is looking at
the sign-in form is interacting with the program over a network too, so
the footer carries it now.
And the two workspace packages declared no licence at all. Private, so
npm never minded, but anything reading the tree saw a blank where the
rest of the project says AGPL-3.0-or-later.
Checked both ways round: with SOURCE_URL set to a fork, the sign-in page
and About both point at the fork; with it unset, both fall back to this
repository.
**The login rate limiter could be sidestepped.** X-Forwarded-For is a list each
hop appends to, and nginx's $proxy_add_x_forwarded_for appends ours — so a
client sending "X-Forwarded-For: 1.2.3.4" arrives as "1.2.3.4, <their real
address>". Reading the leftmost entry, as we did, handed the caller a
rate-limit key they could change per request: unlimited password guessing
against a deployment that looks correctly configured. Read from the right
instead, skip hops that are themselves trusted proxies, and believe the header
only when the peer is one (loopback and the private ranges by default,
TRUSTED_PROXIES to be explicit).
**The upload cap was a suggestion.** It read content-length, which a chunked
request simply omits. Count the bytes through a stream, as the image proxy
already does.
**App password secrets were drawn with a modulo.** 256 is not a multiple of 33,
so the first 25 characters of the alphabet came up on 8 byte values and the
last 8 on only 7. Rejection sampling instead. The test weighs the whole tail of
the alphabet rather than single characters, because a 7/8 skew is invisible
per character against the noise — and it does fail when the bias is put back.
**Upstream headers were relayed wholesale.** Anything the mail server set —
cookies, auth challenges, CORS grants — landed on our origin, where it means
something else. Allowlist what is actually wanted.
jcoffey-dev