These weren't running because Click complained about an ASCII locale
when running under py3, which triggered an error check that was there to
detect broken virtualenvs, skipping those tests.
The fix appears to be to force the en_US.UTF-8 locale when running the
wormhole program in a subprocess.
This adds a test for database upgrades, which I developed on a branch
that added a new DB schema (v3) and an upgrader to match, but then I
changed my mind about the schema and removed that part. The test will be
useful some time in the future when I change the schema in a small
enough way that I bother to write an upgrader for the change. For now,
the test is disabled.
In addition, the upgrader test is kind of lame. I'd really prefer to
assert that the upgraded schema is identical to the schema of a
brand-new (latest-version) database, but ALTER TABLE doesn't quite work
that way (comments are omitted, and the order of the columns is slightly
different).
This also adds database.dump_db() for the tests.
(one displayed message per received welcome["motd"])
There's not much value in prohibiting the server from sending multiple
MOTD messages, and it would prevent us from using it to display a "your
client is using an old API, please upgrade" message after having already
sent a regular "please donate" MOTD message. (We could send a second
welcome message with ["error"] to kill the client, but ["motd"] is the
most convenient way to deliver a non-fatal warning).
The reasoning is that this string is only ever likely to refer to the
version of the primary/initial client (the CLI application, written in
Python, that you get with "pip install magic-wormhole"). When there are
other implementations, with unrelated versions, they should obviously
not pay attention to a warning about the other implementation being out
of date.
This gives us room in the future to put other keys there, like one which
says we want to use Noise for the phase-message encryption instead of
our current HKDF scheme.
This better reflects the purpose of the message. Key confirmation is a
side-effect.
This patch only changes the "phase:" name and the key-derivation string.
A subsequent patch will modify the function and variable names to match.
The file-send protocol now sends a "hints-v1" key in the "transit"
message, which contains a list of JSON data structures that describe the
connection hints (a mixture of direct, tor, and relay hints, for now).
Previously the direct/tor and relay hints were sent in different keys,
and all were sent as strings like "tcp:hostname:1234" which had to be
parsed by the recipient.
The new structures include a version string, to make it easier to add
new types in the future. Transit logs+ignores hints it cannot
understand.
Previously the encryption key used for "phase messages" (anything sent
from one side to the other, protected by the shared PAKE-generated
session key) was derived just from the session key and the phase name.
The two sides would use the same key for their first message (but with
random, thus different, nonces).
This uses the sending side's string (a random 5-byte/10-character hex
string) in the derivation process too, so the two sides use different
keys. This gives us an easy way to reject reflected messages. We already
ignore messages that claim to use a "side" which matches our own (to
ignore server echoes of our own outbound messages). With this change, an
attacker (or the server) can't swap in the payload of an outbound
message, change the "side" to make it look like a peer message, and then
let us decrypt it correctly.
It also changes the derivation function to combine the phase and side
values safely. This didn't matter much when we only had one
externally-provided string, but with two, there's an opportunity for
format confusion if they were combined with a simple delimiter. Now we
hash both values before concatenating them.
This breaks interoperability with clients from before this change. They
will always get WrongPasswordErrors.
