Fix a race regarding client keyPairs caching

internal/client/auth.go

@@ -38,15 +38,17 @@ func MakeSessionTicket(sta *State) []byte {
 	// for encrypting the UID
 	tthInterval := sta.Now().Unix() / int64(sta.TicketTimeHint)
 	ec := ecdh.NewCurve25519ECDH()
-	ephKP := sta.getKeyPair(tthInterval)
+	sta.keyPairsM.Lock()
+	ephKP := sta.keyPairs[tthInterval]
 	if ephKP == nil {
 		ephPv, ephPub, _ := ec.GenerateKey(rand.Reader)
 		ephKP = &keyPair{
 			ephPv,
 			ephPub,
 		}
-		sta.putKeyPair(tthInterval, ephKP)
+		sta.keyPairs[tthInterval] = ephKP
 	}
+	sta.keyPairsM.Unlock()
 	ticket := make([]byte, 192)
 	copy(ticket[0:32], ec.Marshal(ephKP.PublicKey))
 	key, _ := ec.GenerateSharedSecret(ephKP.PrivateKey, sta.staticPub)

internal/client/state.go

@@ -123,15 +123,3 @@ func (sta *State) ParseConfig(conf string) (err error) {
 	sta.staticPub = pub
 	return nil
 }
-
-func (sta *State) getKeyPair(tthInterval int64) *keyPair {
-	sta.keyPairsM.Lock()
-	defer sta.keyPairsM.Unlock()
-	return sta.keyPairs[tthInterval]
-}
-
-func (sta *State) putKeyPair(tthInterval int64, kp *keyPair) {
-	sta.keyPairsM.Lock()
-	sta.keyPairs[tthInterval] = kp
-	sta.keyPairsM.Unlock()
-}

internal/server/usermanager/userpanel.go

@@ -346,7 +346,8 @@ func (up *Userpanel) syncMemFromDB(UID []byte) error {
 	return nil
 }
 
-// the following functions will return err==nil if user is not active
+// the following functions will update the db entries first, then if the
+// user is active, it will update it in memory.
 
 func (up *Userpanel) setSessionsCap(UID []byte, cap uint32) error {
 	err := up.updateDBEntryUint32(UID, "SessionsCap", cap)
@@ -446,6 +447,7 @@ func (up *Userpanel) addUpCredit(UID []byte, delta int64) error {
 	u.addUpCredit(delta)
 	return nil
 }
+
 func (up *Userpanel) addDownCredit(UID []byte, delta int64) error {
 	err := up.db.Update(func(tx *bolt.Tx) error {
 		b := tx.Bucket(UID)