Getting source address of a Tx message from it's signature script
You can't.

If all you have is a capture of the wire traffic for a single tx, you can't (always) compute the actual address.

In a certain subset of cases, such as for standardized scripts such as P2PKH or P2SH multisig, you might be able to assume the script sig to correspond to one of them, if it has the right data.

The scriptsig mentioned is for a segwit address, and is commonly put as the redeem script for P2SH wrapped segwit addresses.

However, note that just because a script sig matches the expected form for an address does not mean that the actual output corresponds to that address. For example, a P2PKH address would have a script sig with two pushes (one for the signature, one for the public key) - If you were so inclined, you could build an output script that simply consumes the top two elements of the stack, and create an output that will accept a P2PKH script sig as valid, while having absolutely no relation to the P2PKH address.

In general, if you want to know the source address, look up the transaction being spent, and use the locking script from that vout.