Ethereum consensus client in Rust
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Michael Sproul edf23bb40e Fix attestation shuffling filter (#3629)
## Issue Addressed

Fix a bug in block production that results in blocks with 0 attestations during the first slot of an epoch.

The bug is marked by debug logs of the form:

> DEBG Discarding attestation because of missing ancestor, block_root: 0x3cc00d9c9e0883b2d0db8606278f2b8423d4902f9a1ee619258b5b60590e64f8, pivot_slot: 4042591

It occurs when trying to look up the shuffling decision root for an attestation from a slot which is prior to fork choice's finalized block. This happens frequently when proposing in the first slot of the epoch where we have:

- `current_epoch == n`
- `attestation.data.target.epoch == n - 1`
- attestation shuffling epoch `== n - 3` (decision block being the last block of `n - 3`)
- `state.finalized_checkpoint.epoch == n - 2` (first block of `n - 2` is finalized)

Hence the shuffling decision slot is out of range of the fork choice backwards iterator _by a single slot_.

Unfortunately this bug was hidden when we weren't pruning fork choice, and then reintroduced in v2.5.1 when we fixed the pruning (https://github.com/sigp/lighthouse/releases/tag/v2.5.1). There's no way to turn that off or disable the filtering in our current release, so we need a new release to fix this issue.

Fortunately, it also does not occur on every epoch boundary because of the gradual pruning of fork choice every 256 blocks (~8 epochs):

01e84b71f5/consensus/proto_array/src/proto_array_fork_choice.rs (L16)

01e84b71f5/consensus/proto_array/src/proto_array.rs (L713-L716)

So the probability of proposing a 0-attestation block given a proposal assignment is approximately `1/32 * 1/8 = 0.39%`.

## Proposed Changes

- Load the block's shuffling ID from fork choice and verify it against the expected shuffling ID of the head state. This code was initially written before we had settled on a representation of shuffling IDs, so I think it's a nice simplification to make use of them here rather than more ad-hoc logic that fundamentally does the same thing.

## Additional Info

Thanks to @moshe-blox for noticing this issue and bringing it to our attention.
2022-10-18 04:02:06 +00:00
.github Ensure protoc is installed for release CI (#3621) 2022-10-03 23:09:25 +00:00
account_manager Builder Specs v0.2.0 (#3134) 2022-07-30 00:22:37 +00:00
beacon_node Fix attestation shuffling filter (#3629) 2022-10-18 04:02:06 +00:00
book Pass EL JWT secret key via cli flag (#3568) 2022-10-04 12:41:03 +00:00
boot_node v3.1.2 (#3603) 2022-09-26 01:17:36 +00:00
common Remove fallback support from eth1 service (#3594) 2022-10-04 08:33:39 +00:00
consensus Consensus context with proposer index caching (#3604) 2022-10-15 22:25:54 +00:00
crypto Add a new bls test (#3235) 2022-10-12 23:40:42 +00:00
database_manager Prune finalized execution payloads (#3565) 2022-09-17 02:27:01 +00:00
lcli Consensus context with proposer index caching (#3604) 2022-10-15 22:25:54 +00:00
lighthouse Pass EL JWT secret key via cli flag (#3568) 2022-10-04 12:41:03 +00:00
scripts Ensure protoc is installed for release CI (#3621) 2022-10-03 23:09:25 +00:00
slasher Modularise slasher backend (#3443) 2022-08-15 01:30:56 +00:00
testing Consensus context with proposer index caching (#3604) 2022-10-15 22:25:54 +00:00
validator_client Publish subscriptions to all beacon nodes (#3529) 2022-09-28 19:53:35 +00:00
.dockerignore Exclude EE build dirs from Docker context (#3174) 2022-05-09 23:43:31 +00:00
.editorconfig Add editorconfig template 2019-03-11 15:09:57 +11:00
.gitignore Allow setting web3signer version through environment (#3368) 2022-07-27 03:20:01 +00:00
.gitmodules Replace EF tests submodule with a makefile 2019-09-08 04:19:54 +10:00
bors.toml Add merge support to simulator (#3292) 2022-07-18 23:15:40 +00:00
Cargo.lock Optimistic sync spec tests (v1.2.0) (#3564) 2022-10-15 22:25:52 +00:00
Cargo.toml Remove fallback support from eth1 service (#3594) 2022-10-04 08:33:39 +00:00
CONTRIBUTING.md [Contribution docs] Add GitPOAP Badge to Display Number of Minted GitPOAPs for Contributors (#3343) 2022-08-09 02:27:04 +00:00
Cross.toml Ensure protoc is installed for release CI (#3621) 2022-10-03 23:09:25 +00:00
Dockerfile Libp2p v0.48.0 upgrade (#3547) 2022-09-29 01:50:11 +00:00
Dockerfile.cross Use a stable tag for ubuntu in dockerfile (#3231) 2022-05-31 06:09:12 +00:00
LICENSE Update License to Apache 2.0 2019-04-15 16:47:35 +10:00
Makefile Add maxperf build profile (#3608) 2022-09-29 06:13:33 +00:00
README.md Changed http:// to https:// on mailing list link (#3610) 2022-09-29 06:13:35 +00:00
SECURITY.md Add how users should report security vulnerabilities for this repository (#2562) 2021-09-07 01:54:05 +00:00

Lighthouse: Ethereum consensus client

An open-source Ethereum consensus client, written in Rust and maintained by Sigma Prime.

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Overview

Lighthouse is:

  • Ready for use on Ethereum consensus mainnet.
  • Fully open-source, licensed under Apache 2.0.
  • Security-focused. Fuzzing techniques have been continuously applied and several external security reviews have been performed.
  • Built in Rust, a modern language providing unique safety guarantees and excellent performance (comparable to C++).
  • Funded by various organisations, including Sigma Prime, the Ethereum Foundation, ConsenSys, the Decentralization Foundation and private individuals.
  • Actively involved in the specification and security analysis of the Ethereum proof-of-stake consensus specification.

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If you are looking to contribute, please head to the Contributing section of the Lighthouse book.

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