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Ian Goldberg
bd7721f66e
Ian's original message:
The current code actually correctly handles queued data at the
Exit; if there is queued data in a EXIT_CONN_STATE_CONNECTING
stream, that data will be immediately sent when the connection
succeeds. If the connection fails, the data will be correctly
ignored and freed. The problem with the current server code is
that the server currently drops DATA cells on streams in the
EXIT_CONN_STATE_CONNECTING state. Also, if you try to queue data
in the EXIT_CONN_STATE_RESOLVING state, bad things happen because
streams in that state don't yet have conn->write_event set, and so
some existing sanity checks (any stream with queued data is at
least potentially writable) are no longer sound.
The solution is to simply not drop received DATA cells while in
the EXIT_CONN_STATE_CONNECTING state. Also do not send SENDME
cells in this state, so that the OP cannot send more than one
window's worth of data to be queued at the Exit. Finally, patch
the sanity checks so that streams in the EXIT_CONN_STATE_RESOLVING
state that have buffered data can pass.
[...] Here is a simple patch. It seems to work with both regular
streams and hidden services, but there may be other corner cases
I'm not aware of. (Do streams used for directory fetches, hidden
services, etc. take a different code path?)
Tor protects your privacy on the internet by hiding the connection
between your Internet address and the services you use. We believe Tor
is reasonably secure, but please ensure you read the instructions and
configure it properly.
To build Tor from source:
./configure && make && make install
Home page:
https://www.torproject.org/
Download new versions:
https://www.torproject.org/download.html
Documentation, including links to installation and setup instructions:
https://www.torproject.org/documentation.html
Making applications work with Tor:
https://wiki.torproject.org/noreply/TheOnionRouter/TorifyHOWTO
Frequently Asked Questions:
https://www.torproject.org/faq.html
https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ