Data requests with RADType::Unknown sources are wrongly accepted into blocks since WIP0020

[tmpolaczyk]

Data requests with RADType::Unknown sources are wrongly accepted into blocks since WIP0020.

Example transaction: 38d8cf497622082fa8fd4e89831641834918a99472b722310d60664046a29883

{"jsonrpc":"2.0","result":{"blockEpoch":1544550,"blockHash":"3a077d6b4064524afa01e1b8781cfb059693653d5138734b0ffef27253a24bc9","confirmed":true,"transaction":{"DataRequest":{"body":{"dr_output":{"collateral":10000000000,"commit_and_reveal_fee":1000,"data_request":{"aggregate":{"filters":[{"args":[251,63,241,153,153,153,153,153,154],"op":5}],"reducer":3},"retrieve":[{"kind":"Unknown","script":[130,24,119,130,24,101,101,108,105,107,101,115],"url":"https://api-middlewares.vercel.app/api/twitter/tweets/0"}],"tally":{"filters":[{"args":[251,63,241,153,153,153,153,153,154],"op":5}],"reducer":3},"time_lock":1630669134},"min_consensus_percentage":51,"witness_reward":1000000,"witnesses":100},"inputs":[{"output_pointer":"7cc0415818cd633916c4a3d3ea097d13e04973a8be010baea39244d83fa6d6bc:0"}],"outputs":[{"pkh":"wit1c0ucz2u9hwgqflkn4xjeyxtla9tqp0sderzkjr","time_lock":0,"value":2166708072}]},"signatures":[{"public_key":{"bytes":[176,193,72,220,165,255,123,112,10,173,38,116,83,157,103,237,213,54,147,62,72,34,100,153,202,212,153,241,200,151,13,32],"compressed":2},"signature":{"Secp256k1":{"der":[48,69,2,33,0,144,199,29,249,135,183,74,33,30,61,204,36,30,87,98,167,21,127,197,46,46,14,71,113,28,140,180,187,140,181,170,26,2,32,52,178,190,191,36,97,187,28,26,178,118,166,244,232,234,177,76,247,204,102,75,70,54,251,121,21,52,208,151,229,70,15]}}}]}},"weight":64009},"id":"1"}

Summary of the behavior:

• Before WIP0019: RADType::Unknown are accepted, and treated as HttpGet.
• WIP0019: RADType::Unknown are rejected.
• WIP0020: RADType::Unknown are accepted, and resolved with RadonTypes::RadonError(UnhandledIntercept { inner: None, message: Some("inner: UnknownRetrieval") }).

This is implemented in the validate_rad_request function:

witnet-rust/validations/src/validations.rs

Line 239 in 11d37d3

pub fn validate_rad_request(

So this looks like a bug introduced when implementing WIP0020. I believe that the intended behavior was to reject RADType::Unknown sources, because they were already being rejected after WIP0019, so that should be fixed.

However, this issue shouldn't have any negative effects on the network, because we used to accept this kind of transactions in the past, and all the other validations are working correctly so it is not possible to abuse this bug to perform double spends or anything like that.