Treat all strings from read buffers as gc-tainted

Rule: Copies must be made before retaining the string.

socketserver/server/backend.go

@@ -93,7 +93,7 @@ func HTTPBackendUncachedPublish(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	cm := ClientMessage{MessageID: -1, Command: CommandPool.Intern(cmd), origArguments: json}
+	cm := ClientMessage{MessageID: -1, Command: CommandPool.InternCommand(cmd), origArguments: json}
 	cm.parseOrigArguments()
 	var count int
 

socketserver/server/commands.go

@@ -41,7 +41,10 @@ var commandHandlers = map[Command]CommandHandler{
 	"user_history":          C2SHandleRemoteCommand,
 }
 
-func internCommands() {
+func setupInterning() {
+	PubSubChannelPool = NewStringPool()
+	TwitchChannelPool = NewStringPool()
+
 	CommandPool = NewStringPool()
 	CommandPool._Intern_Setup(string(HelloCommand))
 	CommandPool._Intern_Setup("ping")
@@ -114,7 +117,7 @@ func C2SHello(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (rmsg
 		return
 	}
 
-	client.VersionString = version
+	client.VersionString = copyString(version)
 	client.Version = VersionFromString(version)
 
 	client.ClientID = uuid.FromStringOrNil(clientID)
@@ -154,6 +157,8 @@ func C2SSetUser(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (rm
 		return
 	}
 
+	username = copyString(username)
+
 	client.Mutex.Lock()
 	client.UsernameValidated = false
 	client.TwitchUsername = username
@@ -198,11 +203,12 @@ func C2SReady(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (rmsg
 
 func C2SSubscribe(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (rmsg ClientMessage, err error) {
 	channel, err := msg.ArgumentsAsString()
-
 	if err != nil {
 		return
 	}
 
+	channel = PubSubChannelPool.Intern(channel)
+
 	client.Mutex.Lock()
 	AddToSliceS(&client.CurrentChannels, channel)
 	if usePendingSubscrptionsBacklog {
@@ -219,11 +225,12 @@ func C2SSubscribe(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (
 // It removes the channel from ClientInfo.CurrentChannels and calls UnsubscribeSingleChat.
 func C2SUnsubscribe(conn *websocket.Conn, client *ClientInfo, msg ClientMessage) (rmsg ClientMessage, err error) {
 	channel, err := msg.ArgumentsAsString()
-
 	if err != nil {
 		return
 	}
 
+	channel = PubSubChannelPool.Intern(channel)
+
 	client.Mutex.Lock()
 	RemoveFromSliceS(&client.CurrentChannels, channel)
 	client.Mutex.Unlock()
@@ -261,6 +268,8 @@ func C2STrackFollow(conn *websocket.Conn, client *ClientInfo, msg ClientMessage)
 	}
 	now := time.Now()
 
+	channel = TwitchChannelPool.Intern(channel)
+
 	followEventsLock.Lock()
 	followEvents = append(followEvents, followEvent{User: client.TwitchUsername, Channel: channel, NowFollowing: following, Timestamp: now})
 	followEventsLock.Unlock()
@@ -323,6 +332,7 @@ func C2SEmoticonUses(conn *websocket.Conn, client *ClientInfo, msg ClientMessage
 			if count > 200 {
 				count = 200
 			}
+			roomName = TwitchChannelPool.Intern(roomName)
 			destMapInner[roomName] += count
 			total += count
 		}
@@ -422,7 +432,7 @@ var bunchCacheCleanupSignal = sync.NewCond(&bunchCacheLock)
 var bunchCacheLastCleanup time.Time
 
 func bunchedRequestFromCM(msg *ClientMessage) bunchedRequest {
-	return bunchedRequest{Command: msg.Command, Param: msg.origArguments}
+	return bunchedRequest{Command: msg.Command, Param: copyString(msg.origArguments)}
 }
 
 // is_init_func
@@ -563,7 +573,7 @@ const AuthorizationFailedErrorString = "Failed to verify your Twitch username."
 const AuthorizationNeededError = "You must be signed in to use that command."
 
 func doRemoteCommand(conn *websocket.Conn, msg ClientMessage, client *ClientInfo) {
-	resp, err := SendRemoteCommandCached(string(msg.Command), msg.origArguments, client.AuthInfo)
+	resp, err := SendRemoteCommandCached(string(msg.Command), copyString(msg.origArguments), client.AuthInfo)
 
 	if err == ErrAuthorizationNeeded {
 		if client.TwitchUsername == "" {

socketserver/server/handlecore.go

@@ -61,6 +61,8 @@ var Configuration *ConfigFile
 var janitorsOnce sync.Once
 
 var CommandPool *StringPool
+var PubSubChannelPool *StringPool
+var TwitchChannelPool *StringPool
 
 // SetupServerAndHandle starts all background goroutines and registers HTTP listeners on the given ServeMux.
 // Essentially, this function completely preps the server for a http.ListenAndServe call.
@@ -115,7 +117,7 @@ func SetupServerAndHandle(config *ConfigFile, serveMux *http.ServeMux) {
 }
 
 func init() {
-	internCommands()
+	setupInterning()
 }
 
 // startJanitors starts the 'is_init_func' goroutines
@@ -514,11 +516,11 @@ func UnmarshalClientMessage(data []byte, payloadType int, v interface{}) (err er
 
 	spaceIdx = strings.IndexRune(dataStr, ' ')
 	if spaceIdx == -1 {
-		out.Command = CommandPool.Intern(dataStr)
+		out.Command = CommandPool.InternCommand(dataStr)
 		out.Arguments = nil
 		return nil
 	} else {
-		out.Command = CommandPool.Intern(dataStr[:spaceIdx])
+		out.Command = CommandPool.InternCommand(dataStr[:spaceIdx])
 	}
 	dataStr = dataStr[spaceIdx+1:]
 	argumentsJSON := string([]byte(dataStr))

socketserver/server/intern.go

@@ -6,19 +6,23 @@ import (
 
 type StringPool struct {
 	sync.RWMutex
-	lookup map[string]Command
+	lookup map[string]string
 }
 
 func NewStringPool() *StringPool {
-	return &StringPool{lookup: make(map[string]Command)}
+	return &StringPool{lookup: make(map[string]string)}
 }
 
 // doesn't lock, doesn't check for dupes.
 func (p *StringPool) _Intern_Setup(s string) {
-	p.lookup[s] = Command(s)
+	p.lookup[s] = s
 }
 
-func (p *StringPool) Intern(s string) Command {
+func (p *StringPool) InternCommand(s string) Command {
+	return Command(p.Intern(s))
+}
+
+func (p *StringPool) Intern(s string) string {
 	p.RLock()
 	ss, exists := p.lookup[s]
 	p.RUnlock()
@@ -32,7 +36,7 @@ func (p *StringPool) Intern(s string) Command {
 	if exists {
 		return ss
 	}
-	ss = Command(string([]byte(s))) // make a copy
+	ss = copyString(s)
-	p.lookup[s] = ss
+	p.lookup[ss] = ss
 	return ss
 }

socketserver/server/publisher.go

@@ -198,7 +198,7 @@ func HTTPBackendCachedPublish(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	cmd := CommandPool.Intern(formData.Get("cmd"))
+	cmd := CommandPool.InternCommand(formData.Get("cmd"))
 	json := formData.Get("args")
 	channel := formData.Get("channel")
 	deleteMode := formData.Get("delete") != ""

socketserver/server/utils.go

@@ -27,6 +27,10 @@ func New4KByteBuffer() interface{} {
 	return make([]byte, 0, 4096)
 }
 
+func copyString(s string) string {
+	return string([]byte(s))
+}
+
 func SealRequest(form url.Values) (url.Values, error) {
 	var nonce [24]byte
 	var err error