session: fix uint64 overflow for dates in far future

This commit fixes an overflow that was caused by serializing the default
date the UI sends (Jan 1st, 9999) to unix nanoseconds.

Author: guggero

session/tlv.go

@@ -35,7 +35,7 @@ func SerializeSession(w io.Writer, session *Session) error {
 		label         = []byte(session.Label)
 		state         = uint8(session.State)
 		typ           = uint8(session.Type)
-		expiry        = uint64(session.Expiry.UnixNano())
+		expiry        = uint64(session.Expiry.Unix())
 		serverAddr    = []byte(session.ServerAddr)
 		devServer     = uint8(0)
 		pairingSecret = session.PairingSecret[:]
@@ -128,7 +128,7 @@ func DeserializeSession(r io.Reader) (*Session, error) {
 	session.Label = string(label)
 	session.State = State(state)
 	session.Type = Type(typ)
-	session.Expiry = time.Unix(0, int64(expiry))
+	session.Expiry = time.Unix(int64(expiry), 0)
 	session.ServerAddr = string(serverAddr)
 	session.DevServer = devServer == 1
 

session/tlv_test.go

@@ -33,7 +33,8 @@ func TestSerializeDeserializeSession(t *testing.T) {
 	mac := createDummyMacaroon(t)
 
 	session, err := NewSession(
-		"this is a session", TypeMacaroonCustom, time.Now(),
+		"this is a session", TypeMacaroonCustom,
+		time.Date(99999, 1, 1, 0, 0, 0, 0, time.UTC),
 		"foo.bar.baz:1234", true,
 	)
 	require.NoError(t, err)
@@ -52,8 +53,7 @@ func TestSerializeDeserializeSession(t *testing.T) {
 	// a struct. So we need to compare the timestamp itself and then make
 	// sure the rest of the session is equal separately.
 	require.Equal(
-		t, session.Expiry.UnixNano(),
-		deserializedSession.Expiry.UnixNano(),
+		t, session.Expiry.Unix(), deserializedSession.Expiry.Unix(),
 	)
 	session.Expiry = time.Time{}
 	deserializedSession.Expiry = time.Time{}