fix: let peers cached their own last headers to avoid be overridden - Githubissues

nervosnetwork / ckb-light-client

CKB light client reference implementation

MIT License

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fix: let peers cached their own last headers to avoid be overridden #177

Closed yangby-cryptape closed 7 months ago

yangby-cryptape commented 7 months ago

Description

At present, only one set of verified last N block headers are cached.

https://github.com/nervosnetwork/ckb-light-client/blob/0a8c34ab0db24c8d3af53a894efb1a443ea7cae4/src/protocols/light_client/peers.rs#L23-L24

But, in fact, all peers could have different sets of last N block headers.

Consider that:

A and B are same chain.
A's tip is N.
B's tip is N+k.
Light client connects to A and B at same time.
The last state proof from B is arrived earlier than A's.

What will be happened?

B's last N headers are cached.
Then, A's last N headers overrides B's.

How to fix that?

Traverse last headers of all peers every time.

Commits

test: reproduce the bug that last headers could be overridden by worse data
fix: let peers cached their own last headers to avoid be overridden