Fix TOCTOU race condition for duplicate attestations#10210
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rolfyone
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Dec 9, 2025
| ### Bug Fixes | ||
| - Fixed a storage issue which sometimes caused Teku to crash during shut down. | ||
| - Fixed `peer_count` metric when using `--metrics-publish-endpoint` feature. | ||
| - Fixed attestation validation checks to avoid broadcasting attestations already seen. |
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we can remove this, the fix is gloas only and for payload attestations (PTC) not attestations.
rolfyone
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Dec 9, 2025
rolfyone
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LGTM just remove changelog imo.
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PR Description
When validating attestations, the node should not propagate an attestation that was previously seen. In our current implementation, the check if the attestation was seen and the resulting validation was not done atomically, which could lead to a race condition where we check two similar attestations but don't consider them seen.
This fix relies on our synchronised
seenPayloadAttestationssetadd()function to perform a second check if the attestation has been seen.Fixed Issue(s)
N/A
Documentation
doc-change-requiredlabel to this PR if updates are required.Changelog
Note
Makes duplicate payload attestation detection atomic in the gossip validator and adds tests to cover the race scenario.
seenPayloadAttestations.add(key)post-validation; returnignore(...)if already present.ignoreAttestationAlreadySeenValidationResult(...)helper and reuse it afteradd(...).ignoreAttestationAlreadySeenValidationResult(...)to centralize logging and ignore result.shouldIgnore_whenAlreadySeen_AfterInitialCheckto simulate concurrent validations and verify ignore-on-second.Written by Cursor Bugbot for commit 9c7b946. This will update automatically on new commits. Configure here.