ihasmail spoke to two generations of Stalwart that are less alike than
their version numbers suggest: 0.16 replaced the REST management API with
JMAP registry objects, changed the shape of FileNode, split its rights
up, and moved configuration into the store. Carrying both meant 34 branch
points across nine files, a 92-line compatibility shim whose only job was
telling them apart, a parallel REST implementation of every credential
operation, and a mock that had to model both.
The branches were not the real cost. The cost was that a wrong answer
about which generation had answered always had somewhere to fall back to,
so it failed quietly rather than loudly: one capability looked for in the
wrong place downgraded every real 0.16 server onto the 0.15 path, which
posted the current password to an endpoint 0.16 had removed, reported the
wrong generation on About, and ran Files on the older code. It reached
production and was recorded as verified when it was not. The mock
mirrored the same wrong placement, which is why the tests agreed.
Removed: the filenode compatibility shim, the dual "registry" | "legacy"
backend in account.ts, the pre-0.16 generation in AccountInfo and
everything that read it, the mock's LEGACY mode and dev:mock:legacy, and
the three test files that existed only to pin 0.15 behaviour.
Sign-in now refuses an older server by name, once, rather than letting
Files, the account locale and credentials each fail in their own way with
nothing connecting them. It says the credentials were fine -- someone
hitting this has typed a correct password, and telling them otherwise
sends them round in circles -- and names the tag to build from. Four
tests cover it, including that no session cookie is minted and that bad
credentials on such a server are still a plain 401.
Two fallbacks went that were not strictly about 0.15, and both for the
same reason the removal is happening. Files no longer answers a refused
filter or sort by fetching every node in the account, which would hide a
real fault behind a performance cliff nobody would notice. And the app
folder lookups now filter on parentId/isTopLevel alone and match names
client-side, since `name` is not a filter Stalwart is known to implement
and one it does not know fails the whole query rather than being ignored.
The last release that runs on 0.15 is tagged stalwart-0.15-support.
Verified against the mock end to end: sign-in, the Files tree on the 0.16
path with the app folder hidden, and self-service credentials over the
registry. 226 web + 75 server tests pass; typecheck and build clean.
Self-service credentials, the About page and Files all keyed off
`urn:stalwart:jmap`, and all three looked for it in the session-level
`capabilities`. Stalwart has never put it there. `Session::new` builds that
list from a fixed set the capability is not part of, in any 0.16.x from
0.16.0 to 0.16.19; it is handed out per-account instead, so it arrives in
`primaryAccounts` and in each account's `accountCapabilities`.
So every real 0.16 server read as pre-0.16. Password changes, 2FA and app
passwords fell back to `POST /api/account/auth`, which 0.16 removed, and
reported that the server offers no self-service credential management. About
named the wrong generation. Files ran the pre-0.16 path, omitting `nodeType`
and listing the tree through get.
Look in all three places, on both sides. Two nearby soft spots go with it: a
transport error while probing the registry no longer downgrades a server to
the legacy path -- which would have posted the current password to an
endpoint that is not there -- and a locale request that is merely refused no
longer discards a generation the capability had already settled.
The mock advertised the capability in the session, which is why no test ever
caught this; it now advertises it where the real server does, and validates
`using` by the urn rather than by the session, as Stalwart does. Put the old
lookup back and nine tests fail.
Stalwart still publishes no version number to clients -- VERSION_PUBLIC is a
fixed "1.0.0" -- so About continues to report the generation and edition,
which are now the right ones.
**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.
Stalwart before 0.16 does not know urn:stalwart:jmap, and rejects the whole
request rather than the one call when `using` names a capability it cannot
parse. The probe is only sent when the session advertises that capability, so
this should not arise — but if it ever does, throwing turns a server we can
still manage credentials on into a Security page that only shows an error.
Fall through to the endpoint those servers do have.
Settings › Security grows three working sections instead of a note telling
people to use Stalwart's own portal.
Stalwart moved this API between releases, so ihasmail speaks both: 0.16+ has
the x:AccountPassword singleton and x:AppPassword registry objects over JMAP,
while 0.15.x has the /api/account/auth REST endpoint. Which one answers the
probe is the only reliable way to tell them apart, and the result is cached
per session. The built-in `user` role already grants sysAccountPassword* and
sysAppPassword*, so no administrator setup is needed.
Two problems are worth calling out, because both would bite a user hard:
Stalwart validates the credentials already on the account when 2FA is turned
on and never checks the new secret, so an authenticator that was mistyped or
out of step would lock someone out of their mailbox at the next sign-in. We
verify a code against the new secret ourselves first (RFC 6238, tested against
the spec's vectors) and only then ask the server to store anything.
Every proxied call re-authenticates with the credential sealed into the
session, and from the moment 2FA is on Stalwart wants a fresh TOTP code with
it — which we cannot produce between requests. Turning 2FA on would therefore
sign the user out of the browser they just turned it on in. App passwords
authenticate without a second factor, so the session is moved onto one minted
for this browser, and the session cookie is re-sealed with it. The order
matters: it is minted while the old credential still works, and revoked again
if enabling then fails.
Password changes re-seal this session too and drop the others, whose sealed
copies of the old password would fail on their next call.
The mock now enforces what a real server does — current password, password
policy, a TOTP code on every request once 2FA is on, app passwords exempt —
so the whole flow is exercised in tests rather than only by hand.
jcoffey-dev