fix receiving a batch commit_sig messages

Author: remyers

channeld/channeld.c

@@ -2010,30 +2010,33 @@ static struct commitsig_info *handle_peer_commit_sig(struct peer *peer,
 	htlc_sigs = unraw_sigs(tmpctx, raw_sigs,
 			       channel_has_anchors(peer->channel));
 
-	if (commit_index) {
+	// - If `batch` is smaller than or equal to `1`:
+	//   - MUST send an `error` and fail the channel.
+	if (cs_tlv && cs_tlv->splice_info && cs_tlv->splice_info->batch_size <= 1)
+		peer_failed_err(peer->pps, &peer->channel_id,
+			"Must only set batch tlv for batches greater than 1");
+
+	if (commit_index > 0) {
 		outpoint = peer->splice_state->inflights[commit_index - 1]->outpoint;
 		funding_sats = peer->splice_state->inflights[commit_index - 1]->amnt;
+	}
+	else {
+		outpoint = peer->channel->funding;
+		funding_sats = peer->channel->funding_sats;
+	}
 
-		if (!cs_tlv || !cs_tlv->splice_info)
-			peer_failed_err(peer->pps, &peer->channel_id,
-					"Must set funding_txid for each"
-					" extra commitment_signed message.");
-
-		status_info("handle_peer_commit_sig for inflight outpoint %s", fmt_bitcoin_txid(tmpctx, &peer->splice_state->inflights[commit_index - 1]->outpoint.txid));
+	if (cs_tlv && cs_tlv->splice_info) {
+		status_info("handle_peer_commit_sig for outpoint %s", fmt_bitcoin_txid(tmpctx, &outpoint.txid));
 		status_info("handle_peer_commit_sig cs_tlv->splice_info->funding_txid %s", fmt_bitcoin_txid(tmpctx, &cs_tlv->splice_info->funding_txid));
 
-		if (!bitcoin_txid_eq(&peer->splice_state->inflights[commit_index - 1]->outpoint.txid,
-				     &cs_tlv->splice_info->funding_txid))
+		if (!bitcoin_txid_eq(&outpoint.txid,
+				&cs_tlv->splice_info->funding_txid))
 			peer_failed_err(peer->pps, &peer->channel_id,
 					"Expected commit sig message for %s but"
 					" got %s",
-					fmt_bitcoin_txid(tmpctx, &peer->splice_state->inflights[commit_index - 1]->outpoint.txid),
+					fmt_bitcoin_txid(tmpctx, &outpoint.txid),
 					fmt_bitcoin_txid(tmpctx, &cs_tlv->splice_info->funding_txid));
 	}
-	else {
-		outpoint = peer->channel->funding;
-		funding_sats = peer->channel->funding_sats;
-	}
 
 	txs = channel_txs(tmpctx, &outpoint, funding_sats, &htlc_map,
 			  NULL, &funding_wscript, peer->channel,
@@ -2177,7 +2180,7 @@ static struct commitsig_info *handle_peer_commit_sig(struct peer *peer,
 	result->old_secret = old_secret;
 	/* Only the parent call continues from here.
 	 * Return for all child calls. */
-	if (commit_index)
+	if (batch_index > 0)
 		return result;
 
 	if (tal_count(msg_batch) - 1 < tal_count(peer->splice_state->inflights))
@@ -2203,7 +2206,7 @@ static struct commitsig_info *handle_peer_commit_sig(struct peer *peer,
 						changed_htlcs, sub_splice_amnt,
 						funding_diff - sub_splice_amnt,
 						local_index, local_per_commit,
-						allow_empty_commit, NULL);
+						allow_empty_commit, msg_batch);
 		old_secret = result->old_secret;
 		tal_arr_expand(&commitsigs, result->commitsig);
 		tal_steal(commitsigs, result);
@@ -2367,7 +2370,7 @@ static struct commitsig_info *handle_peer_commit_sig_batch(struct peer *peer,
 	status_debug("Sorting the msg_batch of tal_count %d, batch_size: %d", (int)tal_count(msg_batch), (int)batch_size);
 	asort(msg_batch, tal_count(msg_batch), commit_cmp, peer);
 
-	return handle_peer_commit_sig(peer, msg, commit_index, remote_funding,
+	return handle_peer_commit_sig(peer, msg_batch[0], commit_index, remote_funding,
 				      changed_htlcs, splice_amnt,
 				      remote_splice_amnt, local_index,
 				      local_per_commit, allow_empty_commit,
@@ -5399,7 +5402,7 @@ static void peer_reconnect(struct peer *peer,
 #endif
 
 	inflight = last_inflight(peer);
-	
+
 	if (feature_negotiated(peer->our_features, peer->their_features, OPT_SPLICE)) {
 		/* Subtle: we free tmpctx below as we loop, so tal off peer */
 		send_tlvs = tlv_channel_reestablish_tlvs_new(peer);
@@ -5411,12 +5414,12 @@ static void peer_reconnect(struct peer *peer,
 		*/
 		if (peer->splice_state->locked_ready[REMOTE] && peer->splice_state->remote_locked_txid != NULL) {
 			send_tlvs->your_last_funding_locked_txid = tal_dup(send_tlvs, struct bitcoin_txid, peer->splice_state->remote_locked_txid);
-		} 
+		}
 		else {
 			send_tlvs->your_last_funding_locked_txid = tal_dup(send_tlvs, struct bitcoin_txid, &peer->channel->funding.txid);
 		}
 
-		/* 
+		/*
 		* my_current_funding_locked tlv:
 		* - as a sender, you just send it to your latest locally locked (ie deeply confirmed) splice transaction
 		* - as a receiver, this tells you whether your peer will be sending a splice_locked that you haven't received yet