ecrecover precompile allows EIP-155 style v value

[axic]

As discussed in ethereum/yellowpaper#860 the ecrecover precompile only allows v={27,28} and no other value.

The precompile code (here) calls ecdsa::is_valid_signature to check r/s values and ecdsa::v_to_y_parity_and_chain_id to retrieve the v value.

This latter seems to silently allow EIP-155 style v values too, which would be against the spec.

[yperbasis]

It's not a problem because later the precompile rejects EIP-155 values.

[axic]

Oh you mean the parity_and_id->chain_id != std::nullopt part? Yeah, it is a bit confusing, but I see all of this has been rewritten/reworked now.