[r3.4] cl/sentinel: fix panic on short attnets ENR entry#20493
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A malformed attnets ENR can decode into a Bitvector64 shorter than 8 bytes, causing 'index out of range' panic in findPeersForSubnets when indexing peerSubnets[subnetIdx/8]. Reject such nodes.
domiwei
approved these changes
Apr 11, 2026
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Cherry-pick of #20492 to release/3.4.
Summary
Fixes a panic seen in the wild:
A malformed/short
attnetsENR entry decodes into abitfield.Bitvector64shorter than the expected 8 bytes, so indexingpeerSubnets[subnetIdx/8]goes out of range whensubnetIdx >= 8.Adds a
len(peerSubnets) == 8guard at all three call sites incl/sentinel/discovery.go.