Security: Handle small numbers of initial peers better, Credit: Equilibrium #2154
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Instead, log an error and return immediately.
If there is a small number of initial peers, and they are slow, the initial candidate set update can appear to hang. To avoid this issue, limit the initial candidate set fanout to the number of initial peers. Once the initial peers have sent us more peer addresses, there is no need to limit the fanouts for future updates. Reported by Niklas Long of Equilibrium.
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dconnolly
reviewed
May 17, 2021
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| if peers.is_empty() { | ||
| error!("no initial peers in the network config. Hint: you must configure at least one peer or DNS seeder to run Zebra"); | ||
| return HashSet::new(); |
dconnolly
reviewed
May 17, 2021
| @@ -159,7 +178,7 @@ where | |||
| // called while the peer set is already loaded. | |||
| let mut responses = FuturesUnordered::new(); | |||
| trace!("sending GetPeers requests"); | |||
| for _ in 0..constants::GET_ADDR_FANOUT { | |||
| for _ in 0..fanout_limit.unwrap_or(constants::GET_ADDR_FANOUT) { | |||
dconnolly
approved these changes
May 17, 2021
This was referenced May 18, 2021
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Motivation
3*75seconds, but that's a long time to wait.)Reported by Niklas Long of Equilibrium.
Solution
The code in this pull request has:
Review
@dconnolly or @conradoplg can review. This PR blocks #1849, so it would be nice to get it in soon.
Follow Up Work
It would be nice to avoid the initial update entirely. But it's a workaround for a
zcashdnetwork protocol choice, so there's not much we can do here.