PaperMC/paper-server/patches/sources/net/minecraft/world/level/BaseCommandBlock.java.patch

--- a/net/minecraft/world/level/BaseCommandBlock.java
+++ b/net/minecraft/world/level/BaseCommandBlock.java
@@ -33,6 +33,10 @@
     private String command = "";
     @Nullable
     private Component customName;
+    // CraftBukkit start
+    @Override
+    public abstract org.bukkit.command.CommandSender getBukkitSender(CommandSourceStack wrapper);
+    // CraftBukkit end
 
     public BaseCommandBlock() {}
 
@@ -132,7 +136,7 @@
 
                         });
 
-                        minecraftserver.getCommands().performPrefixedCommand(commandlistenerwrapper, this.command);
+                        minecraftserver.getCommands().dispatchServerCommand(commandlistenerwrapper, this.command); // CraftBukkit
                     } catch (Throwable throwable) {
                         CrashReport crashreport = CrashReport.forThrowable(throwable, "Executing command block");
                         CrashReportCategory crashreportsystemdetails = crashreport.addCategory("Command to be executed");
@@ -174,6 +178,7 @@
     @Override
     public void sendSystemMessage(Component message) {
         if (this.trackOutput) {
+            org.spigotmc.AsyncCatcher.catchOp("sendSystemMessage to a command block"); // Paper - Don't broadcast messages to command blocks
             SimpleDateFormat simpledateformat = BaseCommandBlock.TIME_FORMAT;
             Date date = new Date();
 
@@ -200,7 +205,7 @@
     }
 
     public InteractionResult usedBy(Player player) {
-        if (!player.canUseGameMasterBlocks()) {
+        if (!player.canUseGameMasterBlocks() && (!player.isCreative() || !player.getBukkitEntity().hasPermission("minecraft.commandblock"))) { // Paper - command block permission
             return InteractionResult.PASS;
         } else {
             if (player.getCommandSenderWorld().isClientSide) {