hsmd: method to sign liquidity ad offer

When we accept a bid to create a channel lease, we send back a signature committing to our max channel lease amounts.
rsouvik · Jul 20, 2021 · 3a7b376 · 3a7b376
1 parent b1982f0
commit 3a7b376
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Showing 6 changed files with 133 additions and 2 deletions.
diff --git a/hsmd/capabilities.h b/hsmd/capabilities.h
@@ -7,6 +7,7 @@
 #define HSM_CAP_COMMITMENT_POINT 8
 #define HSM_CAP_SIGN_REMOTE_TX 16
 #define HSM_CAP_SIGN_CLOSING_TX 32
+#define HSM_CAP_SIGN_WILL_FUND_OFFER 64
 
 #define HSM_CAP_MASTER 1024
 #endif /* LIGHTNING_HSMD_CAPABILITIES_H */
diff --git a/hsmd/hsmd.c b/hsmd/hsmd.c
@@ -663,6 +663,7 @@ static struct io_plan *handle_client(struct io_conn *conn, struct client *c)
 	case WIRE_HSMD_GET_CHANNEL_BASEPOINTS:
 	case WIRE_HSMD_SIGN_INVOICE:
 	case WIRE_HSMD_SIGN_MESSAGE:
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER:
 	case WIRE_HSMD_SIGN_BOLT12:
 	case WIRE_HSMD_ECDH_REQ:
 	case WIRE_HSMD_CHECK_FUTURE_SECRET:
@@ -689,6 +690,7 @@ static struct io_plan *handle_client(struct io_conn *conn, struct client *c)
 	case WIRE_HSMSTATUS_CLIENT_BAD_REQUEST:
 	case WIRE_HSMD_SIGN_COMMITMENT_TX_REPLY:
 	case WIRE_HSMD_SIGN_TX_REPLY:
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER_REPLY:
 	case WIRE_HSMD_GET_PER_COMMITMENT_POINT_REPLY:
 	case WIRE_HSMD_CHECK_FUTURE_SECRET_REPLY:
 	case WIRE_HSMD_GET_CHANNEL_BASEPOINTS_REPLY:

diff --git a/hsmd/hsmd_wire.csv b/hsmd/hsmd_wire.csv
@@ -212,3 +212,12 @@ msgdata,hsmd_sign_bolt12,publictweak,u8,publictweaklen
 msgtype,hsmd_sign_bolt12_reply,125
 msgdata,hsmd_sign_bolt12_reply,sig,bip340sig,
 
+# Sign an option_will_fund offer hash
+msgtype,hsmd_sign_option_will_fund_offer,26
+msgdata,hsmd_sign_option_will_fund_offer,funding_pubkey,pubkey,
+msgdata,hsmd_sign_option_will_fund_offer,blockheight,u32,
+msgdata,hsmd_sign_option_will_fund_offer,channel_fee_base_max_msat,u32,
+msgdata,hsmd_sign_option_will_fund_offer,channel_fee_proportional_basis_max,u16,
+
+msgtype,hsmd_sign_option_will_fund_offer_reply,126
+msgdata,hsmd_sign_option_will_fund_offer_reply,rsig,secp256k1_ecdsa_signature,
diff --git a/hsmd/hsmd_wiregen.c b/hsmd/hsmd_wiregen.c
diff --git a/hsmd/hsmd_wiregen.h b/hsmd/hsmd_wiregen.h
diff --git a/hsmd/libhsmd.c b/hsmd/libhsmd.c
@@ -93,6 +93,9 @@ bool hsmd_check_client_capabilities(struct hsmd_client *client,
 	case WIRE_HSMD_SIGN_MUTUAL_CLOSE_TX:
 		return (client->capabilities & HSM_CAP_SIGN_CLOSING_TX) != 0;
 
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER:
+		return (client->capabilities & HSM_CAP_SIGN_WILL_FUND_OFFER) != 0;
+
 	case WIRE_HSMD_INIT:
 	case WIRE_HSMD_CLIENT_HSMFD:
 	case WIRE_HSMD_SIGN_WITHDRAWAL:
@@ -119,6 +122,7 @@ bool hsmd_check_client_capabilities(struct hsmd_client *client,
 	case WIRE_HSMSTATUS_CLIENT_BAD_REQUEST:
 	case WIRE_HSMD_SIGN_COMMITMENT_TX_REPLY:
 	case WIRE_HSMD_SIGN_TX_REPLY:
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER_REPLY:
 	case WIRE_HSMD_GET_PER_COMMITMENT_POINT_REPLY:
 	case WIRE_HSMD_CHECK_FUTURE_SECRET_REPLY:
 	case WIRE_HSMD_GET_CHANNEL_BASEPOINTS_REPLY:
@@ -468,6 +472,53 @@ static u8 *handle_sign_message(struct hsmd_client *c, const u8 *msg_in)
 	return towire_hsmd_sign_message_reply(NULL, &rsig);
 }
 
+/*~ lightningd asks us to sign a liquidity ad offer */
+static u8 *handle_sign_option_will_fund_offer(struct hsmd_client *c,
+					      const u8 *msg_in)
+{
+	struct pubkey funding_pubkey;
+	u32 blockheight, channel_fee_base_max_msat;
+	u16 channel_fee_proportional_basis_max;
+	struct sha256_ctx sctx = SHA256_INIT;
+	struct sha256 sha;
+	secp256k1_ecdsa_signature sig;
+	struct privkey node_pkey;
+
+	if (!fromwire_hsmd_sign_option_will_fund_offer(msg_in,
+						       &funding_pubkey,
+						       &blockheight,
+						       &channel_fee_base_max_msat,
+						       &channel_fee_proportional_basis_max))
+		return hsmd_status_malformed_request(c, msg_in);
+
+	/* BOLT- #2:
+	 *   - MUST set `signature` to the ECDSA signature of
+	 *     SHA256("option_will_fund" || `funding_pubkey`|| `blockheight` ||
+	 *     `channel_fee_base_max_msat` ||
+	 *     `channel_fee_proportional_basis_max`)
+	 */
+	sha256_update(&sctx, "option_will_fund",
+		      strlen("option_will_fund"));
+	sha256_update(&sctx, &funding_pubkey, sizeof(funding_pubkey));
+	sha256_update(&sctx, &blockheight, sizeof(blockheight));
+	sha256_update(&sctx, &channel_fee_base_max_msat,
+		      sizeof(channel_fee_base_max_msat));
+	sha256_update(&sctx, &channel_fee_base_max_msat,
+		      sizeof(channel_fee_base_max_msat));
+	sha256_done(&sctx, &sha);
+
+	node_key(&node_pkey, NULL);
+
+	if (!secp256k1_ecdsa_sign(secp256k1_ctx, &sig,
+				  sha.u.u8,
+				  node_pkey.secret.data,
+				  NULL, NULL))
+		return hsmd_status_bad_request(c, msg_in,
+					       "Failed to sign message");
+
+	return towire_hsmd_sign_option_will_fund_offer_reply(NULL, &sig);
+}
+
 /*~ lightningd asks us to sign a bolt12 (e.g. offer). */
 static u8 *handle_sign_bolt12(struct hsmd_client *c, const u8 *msg_in)
 {
@@ -1352,6 +1403,8 @@ u8 *hsmd_handle_client_message(const tal_t *ctx, struct hsmd_client *client,
 		return handle_ecdh(client, msg);
 	case WIRE_HSMD_SIGN_INVOICE:
 		return handle_sign_invoice(client, msg);
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER:
+		return handle_sign_option_will_fund_offer(client, msg);
 	case WIRE_HSMD_SIGN_BOLT12:
 		return handle_sign_bolt12(client, msg);
 	case WIRE_HSMD_SIGN_MESSAGE:
@@ -1397,6 +1450,7 @@ u8 *hsmd_handle_client_message(const tal_t *ctx, struct hsmd_client *client,
 	case WIRE_HSMSTATUS_CLIENT_BAD_REQUEST:
 	case WIRE_HSMD_SIGN_COMMITMENT_TX_REPLY:
 	case WIRE_HSMD_SIGN_TX_REPLY:
+	case WIRE_HSMD_SIGN_OPTION_WILL_FUND_OFFER_REPLY:
 	case WIRE_HSMD_GET_PER_COMMITMENT_POINT_REPLY:
 	case WIRE_HSMD_CHECK_FUTURE_SECRET_REPLY:
 	case WIRE_HSMD_GET_CHANNEL_BASEPOINTS_REPLY: