Like any normal person, I spend a lot of time lurking in the #support channel of the Uniswap Discord. (Disclosure: Uniswap is a portfolio co

Ethereum is a Dark Forest

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Style Pass

2021-06-24 23:30:03

Like any normal person, I spend a lot of time lurking in the #support channel of the Uniswap Discord. (Disclosure: Uniswap is a portfolio company of Paradigm.)

On Wednesday afternoon, someone asked whether it was possible to recover Uniswap liquidity tokens that had been accidentally sent to the pair contract itself.

My initial thought was that the tokens would be locked forever. But late that night, I had the sudden realization that if the tokens were still there, they could be recovered — by anyone.

When anyone calls the burn function on a Uniswap core contract, the contract measures its own liquidity token balance and burns it, giving the withdrawn tokens to the address specified by the caller. This is a core part of the intended behavior of Uniswap v2 (the basic mechanism is described in section 3.2 of the Uniswap v2 whitepaper).

It’s no secret that the Ethereum blockchain is a highly adversarial environment. If a smart contract can be exploited for profit, it eventually will be. The frequency of new hacks indicates that some very smart people spend a lot of time examining contracts for vulnerabilities.