BlockTransactionRequest: Non-conformity of BIP-152 in rust bitcoin

[hax0kartik]

I got a crash in BlockTransactionRequest deserialization target as rust-bitcoin does not conform to BIP-152 and treats indexes as uint64_t values when according to BIP and Core, they should be treated as uint16_t values.

This also makes it possible to theoretically create a non-conformant BlockTransactions/BlockTxn message with more than U16_MAX transactions in a Block. ("Theoretically" because I am not sure whether a node would have a Block with such a large number of transactions anyway)

I think at the bare minimum, rust-bitcoin should return an error with an index greater than u16 max while deserializing a BlockTransactionRequest.

[apoelstra]

cc rust-bitcoin/rust-bitcoin#2970

[hax0kartik]

cc rust-bitcoin/rust-bitcoin#2970

Hi, please correct me if I am wrong but I think that's an unrelated issue in HeaderandShortIds while this is a issue with BlockTransactionRequest

[apoelstra]

Oh! You're right, sorry. I saw "BIP-152" and thought it was a dupe.