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transit key is derived from the wrong APPID, bummer

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When I made it possible to override APPID with a CLI argument (issue #113), I
forgot to also change this w.derive_key() (issue #339). We don't really need
to include APPID in that purpose string at all (the ideal code would be just
`w.derive_key("transit-key", length)`), but we're stuck with it now. Both
sides must use the same derivation process, and it would be pretty
expensive/complicated to negotiate the process ahead of time (and this code
is scheduled to be obsoleted by Dilation anyways).

I added a note to the two sites that use it, and put a local copy of the
APPID there. We should treat that copy as an arbitrary magic string that must
be included for compatibility with existing deployments (potential
file-transfer peers), which is coincidentally similar to the default `APPID`.

closes #339
This commit is contained in:
Brian Warner 2019-07-24 11:04:36 -07:00
parent 20496e3976
commit c068bfdfdd
2 changed files with 13 additions and 2 deletions
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7
src/wormhole/cli/cmd_receive.py
View File

@ -245,7 +245,12 @@ class Receiver:
reactor=self._reactor,
timing=self.args.timing)
self._transit_receiver = tr
transit_key = w.derive_key(APPID + u"/transit-key",
# When I made it possible to override APPID with a CLI argument
# (issue #113), I forgot to also change this w.derive_key() (issue
# #339). We're stuck with it now. Use a local constant to make this
# clear.
BUG339_APPID = u"lothar.com/wormhole/text-or-file-xfer"
transit_key = w.derive_key(BUG339_APPID + u"/transit-key",
tr.TRANSIT_KEY_LENGTH)
tr.set_transit_key(transit_key)

8
src/wormhole/cli/cmd_send.py
View File

@ -181,8 +181,14 @@ class Sender:
}
self._send_data({u"transit": sender_transit}, w)
# When I made it possible to override APPID with a CLI argument
# (issue #113), I forgot to also change this w.derive_key()
# (issue #339). We're stuck with it now. Use a local constant to
# make this clear.
BUG339_APPID = u"lothar.com/wormhole/text-or-file-xfer"
# TODO: move this down below w.get_message()
transit_key = w.derive_key(APPID + "/transit-key",
transit_key = w.derive_key(BUG339_APPID + "/transit-key",
ts.TRANSIT_KEY_LENGTH)
ts.set_transit_key(transit_key)