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send-twisted: set transit key before sending phase1

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This ensures that we'll be ready for them. Previously there was a race
between us revealing the direct hints to the peer, and us setting the
transit key (thus allowing us to check inbound handshake requests). The
Transit instance didn't handle the race, causing errors to be thrown
when the other side connected quickly.
This commit is contained in:
Brian Warner 2016-02-17 19:01:20 -08:00
parent aa27bfd32c
commit 7f056ca075
1 changed files with 9 additions and 6 deletions
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13
src/wormhole/scripts/cmd_send_twisted.py
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@ -55,9 +55,13 @@ def send_twisted(args):
print(u"Wormhole code is: %s" % code, file=args.stdout)
print(u"", file=args.stdout)
if args.verify:
# get the verifier, because that also lets us derive the transit key,
# which we want to set before revealing the connection hints to the far
# side, so we'll be ready for them when they connect
verifier_bytes = yield w.get_verifier()
verifier = binascii.hexlify(verifier_bytes).decode("ascii")
if args.verify:
while True:
ok = six.moves.input("Verifier %s. ok? (yes/no): " % verifier)
if ok.lower() == "yes":
@ -67,6 +71,9 @@ def send_twisted(args):
}).encode("utf-8")
yield w.send_data(reject_data)
raise TransferError("verification rejected, abandoning transfer")
if fd_to_send is not None:
transit_key = w.derive_key(APPID+"/transit-key")
transit_sender.set_transit_key(transit_key)
my_phase1_bytes = json.dumps(phase1).encode("utf-8")
yield w.send_data(my_phase1_bytes)
@ -92,10 +99,6 @@ def send_twisted(args):
raise TransferError("ambiguous response from remote, "
"transfer abandoned: %s" % (them_phase1,))
tdata = them_phase1["transit"]
# this is happening too late: the other side already connects to our
# server
transit_key = w.derive_key(APPID+"/transit-key")
transit_sender.set_transit_key(transit_key)
yield w.close()
yield _send_file_twisted(tdata, transit_sender, fd_to_send,
args.stdout, args.hide_progress)