splice: Update splice signature msg type

Update to use spec signature type.

Changelog-None

Author: ddustin

channeld/channeld.c

@@ -3218,8 +3218,6 @@ static void resume_splice_negotiation(struct peer *peer,
 	struct wally_psbt *current_psbt = inflight->psbt;
 	struct commitsig *their_commit;
 	const struct witness **outws;
-	u8 der[73];
-	size_t der_len;
 	struct bitcoin_signature splice_sig;
 	struct bitcoin_tx *bitcoin_tx;
 	u32 splice_funding_index;
@@ -3331,9 +3329,7 @@ static void resume_splice_negotiation(struct peer *peer,
 			      fmt_wally_psbt(tmpctx, current_psbt));
 
 	txsig_tlvs = tlv_txsigs_tlvs_new(tmpctx);
-	der_len = signature_to_der(der, &splice_sig);
-	txsig_tlvs->funding_outpoint_sig = tal_dup_arr(tmpctx, u8, der,
-						       der_len, 0);
+	txsig_tlvs->shared_input_signature = &splice_sig.s;
 
 	/* DTODO: is this finalize call required? */
 	psbt_finalize(current_psbt);
@@ -3422,21 +3418,8 @@ static void resume_splice_negotiation(struct peer *peer,
 		/* BOLT-a8b9f495cac28124c69cc5ee429f9ef2bacb9921 #2:
 		 * Both nodes:
 		 *   - MUST sign the transaction using SIGHASH_ALL */
-		their_sig->sighash_type = SIGHASH_ALL;
-
-		if (!signature_from_der(their_txsigs_tlvs->funding_outpoint_sig,
-				       tal_count(their_txsigs_tlvs->funding_outpoint_sig),
-				       their_sig)) {
-
-			tal_free(their_txsigs_tlvs);
-			peer_failed_warn(peer->pps, &peer->channel_id,
-					 "Splicing bad tx_signatures %s",
-					 tal_hex(msg, msg));
-		}
-		if (peer->splicing)
-			peer->splicing->their_sig = tal_steal(peer->splicing,
-							      their_sig);
-		tal_free(their_txsigs_tlvs);
+		their_sig.sighash_type = SIGHASH_ALL;
+		their_sig.s = *their_txsigs_tlvs->shared_input_signature;
 
 		/* Set the commit_sig on the commitment tx psbt */
 		if (!psbt_input_set_signature(current_psbt,

wire/peer_wire.csv

@@ -70,8 +70,8 @@ msgdata,tx_signatures,tlvs,txsigs_tlvs,
 subtype,witness
 subtypedata,witness,len,u16,
 subtypedata,witness,witness_data,byte,len
-tlvtype,txsigs_tlvs,funding_outpoint_sig,0
-tlvdata,txsigs_tlvs,funding_outpoint_sig,sig,byte,...
+tlvtype,txsigs_tlvs,shared_input_signature,0
+tlvdata,txsigs_tlvs,shared_input_signature,signature,signature,
 msgtype,tx_init_rbf,72
 msgdata,tx_init_rbf,channel_id,channel_id,
 msgdata,tx_init_rbf,locktime,u32,