hsmd: Added output_witscripts, remote_per_commit and option_static_remotekey

to hsm_sign_remote_commitment_tx to allow complete validation.

Author: ksedgwic

bitcoin/tx.c

@@ -398,6 +398,7 @@ struct bitcoin_tx *bitcoin_tx(const tal_t *ctx,
 	tx->input_amounts = tal_arrz(tx, struct amount_sat*, input_count);
 	tx->wtx->locktime = 0;
 	tx->wtx->version = 2;
+	tx->output_witscripts = tal_arrz(tx, struct witscript*, output_count);
 	tx->chainparams = chainparams;
 	return tx;
 }

bitcoin/tx.h

@@ -12,6 +12,10 @@
 
 #define BITCOIN_TX_DEFAULT_SEQUENCE 0xFFFFFFFF
 
+struct witscript {
+    u8 *ptr;
+};
+
 struct bitcoin_txid {
 	struct sha256_double shad;
 };
@@ -24,6 +28,9 @@ struct bitcoin_tx {
 	struct amount_sat **input_amounts;
 	struct wally_tx *wtx;
 
+	/* Need the output wscripts in the HSM to validate transaction */
+	struct witscript **output_witscripts;
+
 	/* Keep a reference to the ruleset we have to abide by */
 	const struct chainparams *chainparams;
 };

channeld/channeld.c

@@ -994,7 +994,10 @@ static secp256k1_ecdsa_signature *calc_commitsigs(const tal_t *ctx,
 
 	msg = towire_hsm_sign_remote_commitment_tx(NULL, txs[0],
 						   &peer->channel->funding_pubkey[REMOTE],
-						   *txs[0]->input_amounts[0]);
+						   *txs[0]->input_amounts[0],
+						   (const struct witscript **) txs[0]->output_witscripts,
+						   &peer->remote_per_commit,
+						   peer->channel->option_static_remotekey);
 
 	msg = hsm_req(tmpctx, take(msg));
 	if (!fromwire_hsm_sign_tx_reply(msg, commit_sig))

channeld/commit_tx.c

@@ -36,7 +36,8 @@ size_t commit_tx_num_untrimmed(const struct htlc **htlcs,
 
 static void add_offered_htlc_out(struct bitcoin_tx *tx, size_t n,
 				 const struct htlc *htlc,
-				 const struct keyset *keyset)
+				 const struct keyset *keyset,
+				 struct witscript * o_wscript)
 {
 	struct ripemd160 ripemd;
 	u8 *wscript, *p2wsh;
@@ -49,12 +50,15 @@ static void add_offered_htlc_out(struct bitcoin_tx *tx, size_t n,
 	SUPERVERBOSE("# HTLC %" PRIu64 " offered %s wscript %s\n", htlc->id,
 		     type_to_string(tmpctx, struct amount_sat, &amount),
 		     tal_hex(wscript, wscript));
+	o_wscript->ptr = tal_dup_arr(o_wscript, u8,
+				     wscript, tal_count(wscript), 0);
 	tal_free(wscript);
 }
 
 static void add_received_htlc_out(struct bitcoin_tx *tx, size_t n,
 				  const struct htlc *htlc,
-				  const struct keyset *keyset)
+				  const struct keyset *keyset,
+				  struct witscript * o_wscript)
 {
 	struct ripemd160 ripemd;
 	u8 *wscript, *p2wsh;
@@ -72,6 +76,8 @@ static void add_received_htlc_out(struct bitcoin_tx *tx, size_t n,
 		     type_to_string(tmpctx, struct amount_sat,
 				    &amount),
 		     tal_hex(wscript, wscript));
+	o_wscript->ptr = tal_dup_arr(o_wscript, u8,
+				     wscript, tal_count(wscript), 0);
 	tal_free(wscript);
 }
 
@@ -169,7 +175,10 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 			continue;
 		if (trim(htlcs[i], feerate_per_kw, dust_limit, side))
 			continue;
-		add_offered_htlc_out(tx, n, htlcs[i], keyset);
+		tx->output_witscripts[n] =
+			tal(tx->output_witscripts, struct witscript);
+		add_offered_htlc_out(tx, n, htlcs[i],
+				     keyset, tx->output_witscripts[n]);
 		(*htlcmap)[n] = htlcs[i];
 		cltvs[n] = abs_locktime_to_blocks(&htlcs[i]->expiry);
 		n++;
@@ -185,7 +194,10 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 			continue;
 		if (trim(htlcs[i], feerate_per_kw, dust_limit, side))
 			continue;
-		add_received_htlc_out(tx, n, htlcs[i], keyset);
+		tx->output_witscripts[n] =
+			tal(tx->output_witscripts, struct witscript);
+		add_received_htlc_out(tx, n, htlcs[i], keyset,
+				      tx->output_witscripts[n]);
 		(*htlcmap)[n] = htlcs[i];
 		cltvs[n] = abs_locktime_to_blocks(&htlcs[i]->expiry);
 		n++;
@@ -209,6 +221,11 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 		SUPERVERBOSE("# to-local amount %s wscript %s\n",
 			     type_to_string(tmpctx, struct amount_sat, &amount),
 			     tal_hex(tmpctx, wscript));
+		tx->output_witscripts[n] =
+			tal(tx->output_witscripts, struct witscript);
+		tx->output_witscripts[n]->ptr =
+			tal_dup_arr(tx->output_witscripts[n], u8,
+				    wscript, tal_count(wscript), 0);
 		n++;
 	}
 
@@ -252,6 +269,7 @@ struct bitcoin_tx *commit_tx(const tal_t *ctx,
 
 	assert(n <= tx->wtx->outputs_allocation_len);
 	tal_resize(htlcmap, n);
+	tal_resize(&(tx->output_witscripts), n);
 
 	/* BOLT #3:
 	 *

common/initial_commit_tx.c

@@ -175,6 +175,11 @@ struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
 		int pos = bitcoin_tx_add_output(
 		    tx, scriptpubkey_p2wsh(tx, wscript), amount);
 		assert(pos == n);
+		tx->output_witscripts[n] =
+			tal(tx->output_witscripts, struct witscript);
+		tx->output_witscripts[n]->ptr =
+			tal_dup_arr(tx->output_witscripts[n], u8,
+				    wscript, tal_count(wscript), 0);
 		n++;
 	}
 
@@ -202,6 +207,8 @@ struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
 
 	assert(n <= tx->wtx->num_outputs);
 
+	tal_resize(&(tx->output_witscripts), n);
+
 	/* BOLT #3:
 	 *
 	 * 7. Sort the outputs into [BIP 69+CLTV

common/permute_tx.c

@@ -174,5 +174,12 @@ void permute_outputs(struct bitcoin_tx *tx, u32 *cltvs, const void **map)
 
 		/* Swap best into first place. */
 		swap_wally_outputs(tx->wtx->outputs, map, cltvs, i, best_pos);
+
+		/* If output_witscripts are present, swap them to match. */
+		if (tx->output_witscripts) {
+			struct witscript *tmp = tx->output_witscripts[i];
+			tx->output_witscripts[i] = tx->output_witscripts[best_pos];
+			tx->output_witscripts[best_pos] = tmp;
+		}
 	}
 }

hsmd/hsm_wire.csv

@@ -158,6 +158,10 @@ msgtype,hsm_sign_remote_commitment_tx,19
 msgdata,hsm_sign_remote_commitment_tx,tx,bitcoin_tx,
 msgdata,hsm_sign_remote_commitment_tx,remote_funding_key,pubkey,
 msgdata,hsm_sign_remote_commitment_tx,funding_amount,amount_sat,
+msgdata,hsm_sign_remote_commitment_tx,num_witscripts,u16,
+msgdata,hsm_sign_remote_commitment_tx,output_witscripts,witscript,num_witscripts
+msgdata,hsm_sign_remote_commitment_tx,remote_per_commit,pubkey,
+msgdata,hsm_sign_remote_commitment_tx,option_static_remotekey,bool,
 
 # channeld asks HSM to sign remote HTLC tx.
 msgtype,hsm_sign_remote_htlc_tx,20

hsmd/hsmd.c

@@ -996,11 +996,17 @@ static struct io_plan *handle_sign_remote_commitment_tx(struct io_conn *conn,
 	struct bitcoin_signature sig;
 	struct secrets secrets;
 	const u8 *funding_wscript;
+	struct witscript **output_witscripts;
+	struct pubkey remote_per_commit;
+	bool option_static_remotekey;
 
 	if (!fromwire_hsm_sign_remote_commitment_tx(tmpctx, msg_in,
 						    &tx,
 						    &remote_funding_pubkey,
-						    &funding))
+						    &funding,
+						    &output_witscripts,
+						    &remote_per_commit,
+						    &option_static_remotekey))
 		bad_req(conn, c, msg_in);
 	tx->chainparams = c->chainparams;
 
@@ -1009,6 +1015,8 @@ static struct io_plan *handle_sign_remote_commitment_tx(struct io_conn *conn,
 		return bad_req_fmt(conn, c, msg_in, "tx must have 1 input");
 	if (tx->wtx->num_outputs == 0)
 		return bad_req_fmt(conn, c, msg_in, "tx must have > 0 outputs");
+	if (tal_count(output_witscripts) != tx->wtx->num_outputs)
+		return bad_req_fmt(conn, c, msg_in, "tx must have matching witscripts");
 
 	get_channel_seed(&c->id, c->dbid, &channel_seed);
 	derive_basepoints(&channel_seed,

openingd/openingd.c

@@ -718,7 +718,10 @@ static bool funder_finalize_channel_setup(struct state *state,
 	msg = towire_hsm_sign_remote_commitment_tx(NULL,
 						   *tx,
 						   &state->channel->funding_pubkey[REMOTE],
-						   state->channel->funding);
+						   state->channel->funding,
+						   (const struct witscript **) (*tx)->output_witscripts,
+						   &state->first_per_commitment_point[REMOTE],
+						   state->channel->option_static_remotekey);
 
 	wire_sync_write(HSM_FD, take(msg));
 	msg = wire_sync_read(tmpctx, HSM_FD);
@@ -1233,7 +1236,10 @@ static u8 *fundee_channel(struct state *state, const u8 *open_channel_msg)
 	msg = towire_hsm_sign_remote_commitment_tx(NULL,
 						   remote_commit,
 						   &state->channel->funding_pubkey[REMOTE],
-						   state->channel->funding);
+						   state->channel->funding,
+						   (const struct witscript **) remote_commit->output_witscripts,
+						   &state->first_per_commitment_point[REMOTE],
+						   state->channel->option_static_remotekey);
 
 	wire_sync_write(HSM_FD, take(msg));
 	msg = wire_sync_read(tmpctx, HSM_FD);

tools/generate-wire.py

@@ -225,6 +225,7 @@ class Type(FieldSet):
         'exclude_entry',
         'fee_states',
         'onionreply',
+        'witscript',
     ]
 
     # Some BOLT types are re-typed based on their field name

wire/fromwire.c

@@ -401,6 +401,19 @@ struct bitcoin_tx_output *fromwire_bitcoin_tx_output(const tal_t *ctx,
 	return output;
 }
 
+struct witscript *fromwire_witscript(const tal_t *ctx, const u8 **cursor, size_t *max)
+{
+	struct witscript *retval = tal(ctx, struct witscript);
+	u16 len = fromwire_u16(cursor, max);
+	if (len == 0) {
+		retval->ptr = NULL;
+	} else {
+		retval->ptr = tal_arr(retval, u8, len);
+		fromwire_u8_array(cursor, max, retval->ptr, len);
+	}
+	return retval;
+}
+
 void fromwire_chainparams(const u8 **cursor, size_t *max,
 			  const struct chainparams **chainparams)
 {

wire/towire.c

@@ -262,6 +262,16 @@ void towire_bitcoin_tx_output(u8 **pptr, const struct bitcoin_tx_output *output)
 	towire_u8_array(pptr, output->script, tal_count(output->script));
 }
 
+void towire_witscript(u8 **pptr, const struct witscript *script)
+{
+	if (script == NULL || script->ptr == NULL) {
+		towire_u16(pptr, 0);
+	} else {
+		towire_u16(pptr, tal_count(script->ptr));
+		towire_u8_array(pptr, script->ptr, tal_count(script->ptr));
+	}
+}
+
 void towire_chainparams(u8 **cursor, const struct chainparams *chainparams)
 {
 	towire_bitcoin_blkid(cursor, &chainparams->genesis_blockhash);

wire/wire.h

@@ -29,6 +29,7 @@ struct bitcoin_txid;
 struct preimage;
 struct ripemd160;
 struct siphash_seed;
+struct witscript;
 
 /* Makes generate-wire.py work */
 typedef char wirestring;
@@ -90,6 +91,7 @@ void towire_siphash_seed(u8 **cursor, const struct siphash_seed *seed);
 
 void towire_bip32_key_version(u8 **cursor, const struct bip32_key_version *version);
 void towire_bitcoin_tx_output(u8 **pptr, const struct bitcoin_tx_output *output);
+void towire_witscript(u8 **pptr, const struct witscript *script);
 void towire_chainparams(u8 **cursor, const struct chainparams *chainparams);
 
 const u8 *fromwire(const u8 **cursor, size_t *max, void *copy, size_t n);
@@ -144,6 +146,8 @@ void fromwire_bip32_key_version(const u8 **cursor, size_t *max,
 				struct bip32_key_version *version);
 struct bitcoin_tx_output *fromwire_bitcoin_tx_output(const tal_t *ctx,
 						     const u8 **cursor, size_t *max);
+struct witscript *fromwire_witscript(const tal_t *ctx,
+				     const u8 **cursor, size_t *max);
 
 void fromwire_chainparams(const u8 **cursor, size_t *max,
 			  const struct chainparams **chainparams);