Merge remote-tracking branch 'slingmann/recovery'

irc/client.go

 	var line string
 	var msg ircmsg.IrcMessage
 
+	defer func() {
+		if r := recover(); r != nil {
+			client.server.logger.Error("internal",
+				fmt.Sprintf("Client caused panic: %v\n%s", r, debug.Stack()))
+			if client.server.RecoverFromErrors() {
+				client.server.logger.Error("internal", "Disconnecting client and attempting to recover")
+			} else {
+				panic(r)
+			}
+		}
+		// ensure client connection gets closed
+		client.destroy()
+	}()
+
 	client.idletimer = NewIdleTimer(client)
 	client.idletimer.Start()
 
 			break
 		}
 	}
-
-	// ensure client connection gets closed
-	client.destroy()
 }
 
 //

irc/config.go

 	Logging []logger.LoggingConfig
 
 	Debug struct {
-		StackImpact StackImpactConfig
+		RecoverFromErrors *bool `yaml:"recover-from-errors"`
+		StackImpact       StackImpactConfig
 	}
 
 	Limits struct {

irc/getters.go

 	return server.password
 }
 
+func (server *Server) RecoverFromErrors() bool {
+	server.configurableStateMutex.RLock()
+	defer server.configurableStateMutex.RUnlock()
+	return server.recoverFromErrors
+}
+
 func (server *Server) ProxyAllowedFrom() []string {
 	server.configurableStateMutex.RLock()
 	defer server.configurableStateMutex.RUnlock()

irc/server.go

 	operclasses                  map[string]OperClass
 	password                     []byte
 	passwords                    *passwd.SaltedManager
+	recoverFromErrors            bool
 	registeredChannels           map[string]*RegisteredChannel
 	registeredChannelsMutex      sync.RWMutex
 	rehashMutex                  sync.Mutex
 		server.name = config.Server.Name
 		server.nameCasefolded = casefoldedName
 	}
-	server.networkName = config.Network.Name
 
 	server.configurableStateMutex.Lock()
+	server.networkName = config.Network.Name
 	if config.Server.Password != "" {
 		server.password = config.Server.PasswordBytes()
 	} else {
 		server.password = nil
 	}
-	server.configurableStateMutex.Unlock()
-
 	// apply new WebIRC command restrictions
 	server.webirc = config.Server.WebIRC
-
 	// apply new PROXY command restrictions
 	server.proxyAllowedFrom = config.Server.ProxyAllowedFrom
+	server.recoverFromErrors = true
+	if config.Debug.RecoverFromErrors != nil {
+		server.recoverFromErrors = *config.Debug.RecoverFromErrors
+	}
+	server.configurableStateMutex.Unlock()
 
 	err = server.connectionLimiter.ApplyConfig(config.Server.ConnectionLimiter)
 	if err != nil {

oragono.yaml

 
 # debug options
 debug:
+    # when enabled, oragono will attempt to recover from certain kinds of
+    # client-triggered runtime errors that would normally crash the server.
+    # this makes the server more resilient to DoS, but could result in incorrect
+    # behavior. deployments that would prefer to "start from scratch", e.g., by
+    # letting the process crash and auto-restarting it with systemd, can set
+    # this to false.
+    recover-from-errors: true
+
     # enabling StackImpact profiling
     stackimpact:
         # whether to use StackImpact