fix #2287 (#2369)

Allow restricting metadata modification to server operators

Author: slingamn

default.yaml

@@ -1150,6 +1150,8 @@ allow-environment-overrides: true
 metadata:
     # can clients store metadata?
     enabled: true
+    # if this is true, only server operators with the `metadata` capability can edit metadata:
+    operator-only-modification: false
     # how many keys can a client subscribe to?
     max-subs: 100
     # how many keys can be stored per entity?

irc/config.go

@@ -715,11 +715,12 @@ type Config struct {
 	}
 
 	Metadata struct {
-		Enabled        bool
-		MaxSubs        int            `yaml:"max-subs"`
-		MaxKeys        int            `yaml:"max-keys"`
-		MaxValueBytes  int            `yaml:"max-value-length"`
-		ClientThrottle ThrottleConfig `yaml:"client-throttle"`
+		Enabled                  bool
+		OperatorOnlyModification bool           `yaml:"operator-only-modification"`
+		MaxSubs                  int            `yaml:"max-subs"`
+		MaxKeys                  int            `yaml:"max-keys"`
+		MaxValueBytes            int            `yaml:"max-value-length"`
+		ClientThrottle           ThrottleConfig `yaml:"client-throttle"`
 	}
 
 	WebPush struct {

irc/handlers.go

@@ -3148,7 +3148,7 @@ func markReadHandler(server *Server, client *Client, msg ircmsg.Message, rb *Res
 func metadataHandler(server *Server, client *Client, msg ircmsg.Message, rb *ResponseBuffer) (exiting bool) {
 	config := server.Config()
 	if !config.Metadata.Enabled {
-		rb.Add(nil, server.name, "FAIL", "METADATA", "FORBIDDEN", utils.SafeErrorParam(msg.Params[0]), "Metadata is disabled on this server")
+		rb.Add(nil, server.name, "FAIL", "METADATA", "FORBIDDEN", utils.SafeErrorParam(msg.Params[0]), client.t("Metadata is disabled on this server"))
 		return
 	}
 
@@ -3163,7 +3163,13 @@ func metadataHandler(server *Server, client *Client, msg ircmsg.Message, rb *Res
 	case "sub", "unsub", "subs":
 		// these are session-local and function the same whether or not the client is registered
 		return metadataSubsHandler(client, subcommand, msg.Params, rb)
-	case "get", "set", "list", "clear", "sync":
+	case "set", "clear":
+		if config.Metadata.OperatorOnlyModification && !client.HasRoleCapabs("metadata") {
+			rb.Add(nil, server.name, "FAIL", "METADATA", "FORBIDDEN", utils.SafeErrorParam(msg.Params[0]), client.t("Only server operators can modify metadata"))
+			return
+		}
+		fallthrough
+	case "get", "list", "sync":
 		if client.registered {
 			return metadataRegisteredHandler(client, config, subcommand, msg.Params, rb)
 		} else {

traditional.yaml

@@ -1121,6 +1121,8 @@ allow-environment-overrides: true
 metadata:
     # can clients store metadata?
     enabled: true
+    # if this is true, only server operators with the `metadata` capability can edit metadata:
+    operator-only-modification: false
     # how many keys can a client subscribe to?
     max-subs: 100
     # how many keys can be stored per entity?