core, eth/downloader: fix resetting below freezer threshold #23949
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR fixes two bugs that can be used by a malicious node to try and push a newly joining node into a bad state (with properly mined - thus costly - blocks).
ancestor + 1instead ofancestor, ending up with 1 header too many in the freezer to import on top.blockchain.SetHeadwhere we had a heuristic that ifhead == current blockthen we assumed it's a startup check, not a real "set the damn head" call. This lead to leaving some dangling data in the freezer and the downloader being unable to pile blocks on top.These issue are only relevant during initial snap sync where the data is pushed directly into the freezer. After initial sync the freezer is delayed by 90K blocks and there's also a cap on the max reorg depth.