Re: URGENT: patch needed ASAP for authority bug

[Roger Dingledine <arma@xxxxxxx>]

On Thu, Apr 15, 2010 at 07:42:46AM -0500, Scott Bennett wrote:
>      I believe I spotted an authority bug with pretty severe consequences
[snip]
>      Here's what I found.  blutmagie's torrc is set up for a target
> throughput rate of 18000 KB/s and a maximum burst rate of 24000 KB/s.
> Olaf noticed that blutmagie was being swamped by a horrendous load of
> incoming connections nearly all the time, so he tried using
> MaxAdvertisedBandwidth to reduce the frequency of inbound connections.
[snip]
>      The problem lies in the consensus document, where it shows (or did
> an hour or so ago),
[snip]
>      The authorities are currently disregarding the limit published in every
> node's descriptor and instead are conjuring up their own numbers.  This needs
> to stop and right away.

This behavior is actually a feature. We cut the latency of the Tor
network in half by rebalancing the network to send more traffic to the
relays that could handle it.

See also
https://blog.torproject.org/blog/torflow-node-capacity-integrity-and-reliability-measurements-hotpets

One downside of this new feature is that the old trick we had,
MaxAdvertisedBandwidth, doesn't as much do what you want.

But that said, there does seem to be a problem here: we're seeing way
more directory requests than we were a few weeks ago. That's translating
into more connections seen by relays.

Is that because we're seeing way more users? Or are Tor clients generating
more directory requests than they "should"? Hm.

--Roger