Merge #593: jade: Pass utxo satoshi value to Jade on signing

90a12a4 jade: Pass utxo satoshi value to Jade on signing (Jamie C. Driver)

Pull request description:

  Pass the utxo value, along with the prior tx (non-witness-utxo) when it
  is available.  Most of the time Jade requires the prior tx but there are
  cases when it can be omitted if the sats value is passed.
  Pass both whenever possible - the precise logic of which is required can
  remain contained in the Jade fw.
  (Improves compatibility with PSBT which does not always contain
  'non-witness-utxo' for segwit inputs.)

ACKs for top commit:
  achow101:
    ACK 90a12a4

Tree-SHA512: 3c5bd8e7817492146d0a5b33d9cd514156342770003b5d8eb3c73efd88f342c565305c8221caf5d4d620099385c2643451713eee04789f893c9fab130dd527a3

hwilib/devices/jade.py

@@ -234,6 +234,7 @@ def _split_at_last_hardened_element(path: Sequence[int]) -> Tuple[Sequence[int],
                     input_txn_bytes = psbtin.non_witness_utxo.serialize_without_witness()
                 if utxo is None:
                     raise Exception('PSBT is missing input utxo information, cannot sign')
+                sats_value = utxo.nValue
                 scriptcode = utxo.scriptPubKey
 
                 if is_p2sh(scriptcode):
@@ -267,8 +268,8 @@ def _split_at_last_hardened_element(path: Sequence[int]) -> Tuple[Sequence[int],
                         signing_multisigs[multisig_name] = (script_variant, threshold, signers)
 
                 # Build the input and add to the list - include some host entropy for AE sigs (although we won't verify)
-                jade_inputs.append({'is_witness': witness_input, 'input_tx': input_txn_bytes, 'script': scriptcode, 'path': path,
-                                    'ae_host_entropy': os.urandom(32), 'ae_host_commitment': os.urandom(32)})
+                jade_inputs.append({'is_witness': witness_input, 'satoshi': sats_value, 'script': scriptcode, 'path': path,
+                                    'input_tx': input_txn_bytes, 'ae_host_entropy': os.urandom(32), 'ae_host_commitment': os.urandom(32)})
 
             # Change output details
             # This is optional, in that if we send it Jade validates the change output script