rpc: validate closing channel address in open channel requests

Our OpenChannelRPC was accepting invalid values for the closing address
field. If we were able to decode the address we would use it in the
script even if the address is for another bitcoin net.

chanacceptor/acceptor_test.go

@@ -55,7 +55,7 @@ func newChanAcceptorCtx(t *testing.T, acceptCallCount int,
 
 	testCtx.acceptor = NewRPCAcceptor(
 		testCtx.receiveResponse, testCtx.sendRequest, testTimeout*5,
-		&chaincfg.TestNet3Params, testCtx.quit,
+		&chaincfg.RegressionNetParams, testCtx.quit,
 	)
 
 	return testCtx
@@ -162,7 +162,7 @@ func (c *channelAcceptorCtx) queryAndAssert(queries map[*lnwire.OpenChannel]*Cha
 func TestMultipleAcceptClients(t *testing.T) {
 	testAddr := "bcrt1qwrmq9uca0t3dy9t9wtuq5tm4405r7tfzyqn9pp"
 	testUpfront, err := chancloser.ParseUpfrontShutdownAddress(
-		testAddr, &chaincfg.TestNet3Params,
+		testAddr, &chaincfg.RegressionNetParams,
 	)
 	require.NoError(t, err)
 

chanacceptor/rpcacceptor_test.go

@@ -20,7 +20,7 @@ func TestValidateAcceptorResponse(t *testing.T) {
 		customError = errors.New("custom error")
 		validAddr   = "bcrt1qwrmq9uca0t3dy9t9wtuq5tm4405r7tfzyqn9pp"
 		addr, _     = chancloser.ParseUpfrontShutdownAddress(
-			validAddr, &chaincfg.TestNet3Params,
+			validAddr, &chaincfg.RegressionNetParams,
 		)
 	)
 
@@ -124,7 +124,7 @@ func TestValidateAcceptorResponse(t *testing.T) {
 			// Create an acceptor, everything can be nil because
 			// we just need the params.
 			acceptor := NewRPCAcceptor(
-				nil, nil, 0, &chaincfg.TestNet3Params, nil,
+				nil, nil, 0, &chaincfg.RegressionNetParams, nil,
 			)
 
 			accept, acceptErr, shutdown, err := acceptor.validateAcceptorResponse(

lnwallet/chancloser/chancloser.go

@@ -918,5 +918,10 @@ func ParseUpfrontShutdownAddress(address string,
 		return nil, fmt.Errorf("invalid address: %v", err)
 	}
 
+	if !addr.IsForNet(params) {
+		return nil, fmt.Errorf("invalid address: %v is not a %s "+
+			"address", addr, params.Name)
+	}
+
 	return txscript.PayToAddrScript(addr)
 }

lnwallet/chancloser/chancloser_test.go

@@ -322,3 +322,58 @@ func TestMaxFeeBailOut(t *testing.T) {
 		})
 	}
 }
+
+// TestParseUpfrontShutdownAddress tests the we are able to parse the upfront
+// shutdown address properly.
+func TestParseUpfrontShutdownAddress(t *testing.T) {
+	t.Parallel()
+
+	var (
+		testnetAddress = "tb1qdfkmwwgdaa5dnezrlhtftvmj5qn2kwgp7n0z6r"
+		regtestAddress = "bcrt1q09crvvuj95x5nk64wsxf5n6ky0kr8358vpx4d8"
+	)
+
+	tests := []struct {
+		name        string
+		address     string
+		params      chaincfg.Params
+		expectedErr string
+	}{
+		{
+			name:        "invalid closing address",
+			address:     "non-valid-address",
+			params:      chaincfg.RegressionNetParams,
+			expectedErr: "invalid address",
+		},
+		{
+			name:        "closing address from another net",
+			address:     testnetAddress,
+			params:      chaincfg.RegressionNetParams,
+			expectedErr: "not a regtest address",
+		},
+		{
+			name:    "valid p2wkh closing address",
+			address: regtestAddress,
+			params:  chaincfg.RegressionNetParams,
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := ParseUpfrontShutdownAddress(
+				tc.address, &tc.params,
+			)
+
+			if tc.expectedErr != "" {
+				require.ErrorContains(t, err, tc.expectedErr)
+				return
+			}
+
+			require.NoError(t, err)
+		})
+	}
+}