Support double and list dynamic values in ClientboundDataStorePacket - #349
Merged
PetteriM1 merged 2 commits intoAug 7, 2026
Merged
Conversation
The DataStoreChange dynamic value is a cereal::DynamicValue variant tagged by alternative index: 0 null, 1 bool, 2 int64, 3 double, 4 string, 5 list, 6 map. Tags 3 and 5 were unhandled and threw IllegalStateException, dropping the packet - vanilla writes every non-integer number as a double and rawtext as a list, so all 1.26.40 data-driven form seeds failed to decode.
A forged varuint length reached new ArrayList<>(length) directly, allowing a large allocation before the loop hits buffer underflow. Cap the pre-size by readableBytes / 4 (each entry carries at least a 4-byte type tag); the loop still terminates on underflow for truncated payloads.
This file contains hidden or 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
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
The
DataStoreChangedynamic value is acereal::DynamicValuevariant tagged by alternative index: 0 null, 1 bool, 2 int64, 3 double, 4 string, 5 list, 6 map. Tags 3 and 5 were unhandled and threwIllegalStateException, dropping the packet. Vanilla writes every non-integer number as a double and rawtext as a list, so all 1.26.40 data-driven form seeds failed to decode.Verified both directions against BDS 1.26.40.8; the tag order matches BDS symbols and the gophertunnel/pmmp implementations.