Add depth limit to SNBT (#87)

2023-06-02 23:07:55 +01:00 · 2023-06-02 23:07:55 +01:00 · e7763fa7ea
parent cbfc1beb6a
commit e7763fa7ea
1 changed files with 116 additions and 0 deletions
--- a/patches/server/0048-Add-depth-limit-to-SNBT.patch
+++ b/patches/server/0048-Add-depth-limit-to-SNBT.patch
@ -0,0 +1,116 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Allink <arclicious@vivaldi.net>
+Date: Fri, 2 Jun 2023 22:13:54 +0100
+Subject: [PATCH] Add depth limit to SNBT
+
+
+diff --git a/src/main/java/net/minecraft/nbt/TagParser.java b/src/main/java/net/minecraft/nbt/TagParser.java
+index fbfe810e8be6cb159742f7fd85e7491b9cefa4dc..82b1d851e310504e7373a967dfb5b0b096d36693 100644
+--- a/src/main/java/net/minecraft/nbt/TagParser.java
+++ b/src/main/java/net/minecraft/nbt/TagParser.java
+@@ -169,8 +169,58 @@ public class TagParser {
+         }
+ 
+         this.expect('}');
+-        return compoundTag;
+
+        // Scissors start - Add depth limit to SNBT
+        return exceedsDepthLimit(compoundTag) ? new CompoundTag() : compoundTag;
+        // Scissors end
+    }
+
+    // Scissors start - Add depth limit to SNBT
+    private boolean exceedsDepthLimit(Tag tag) {
+        return this.exceedsDepthLimit(0, tag);
+    }
+
+    private boolean exceedsDepthLimit(long depth, Tag tag)
+    {
+        if (depth > 256)
+        {
+            return true;
+        }
+
+        if (tag instanceof ListTag listTag)
+        {
+            for (Tag childTag : listTag)
+            {
+                boolean returnValue = this.exceedsDepthLimit(depth + 1, childTag);
+
+                if (returnValue)
+                {
+                    return true;
+                }
+            }
+        } else if (tag instanceof CompoundTag compoundTag)
+        {
+            for (String key: compoundTag.getAllKeys())
+            {
+                Tag childTag = compoundTag.get(key);
+
+                if (childTag == null)
+                {
+                    continue;
+                }
+
+                boolean returnValue = this.exceedsDepthLimit(depth + 1, childTag);
+
+                if (returnValue)
+                {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+     }
+    // Scissors end
+ 
+     private Tag readListTag() throws CommandSyntaxException {
+         this.expect('[');
+@@ -203,7 +253,11 @@ public class TagParser {
+             }
+ 
+             this.expect(']');
+-            return listTag;
+
+            // Scissors start - Add depth limit to SNBT
+            return exceedsDepthLimit(listTag) ? new ListTag() : listTag;
+            // return listTag;
+            // Scissors end
+         }
+     }
+ 
+@@ -228,7 +282,7 @@ public class TagParser {
+     }
+ 
+     private <T extends Number> List<T> readArray(TagType<?> arrayTypeReader, TagType<?> typeReader) throws CommandSyntaxException {
+-        List<T> list = Lists.newArrayList();
+        List<Number> list = Lists.newArrayList(); // Scissors - List<T> -> List<Number>
+ 
+         while(true) {
+             if (this.reader.peek() != ']') {
+@@ -241,11 +295,11 @@ public class TagParser {
+                 }
+ 
+                 if (typeReader == ByteTag.TYPE) {
+-                    list.add((T)((NumericTag)tag).getAsByte());
+                    list.add(((NumericTag)tag).getAsByte()); // Scissors - Remove (T) cast
+                 } else if (typeReader == LongTag.TYPE) {
+-                    list.add((T)((NumericTag)tag).getAsLong());
+                    list.add(((NumericTag)tag).getAsLong()); // Scissors - Remove (T) cast
+                 } else {
+-                    list.add((T)((NumericTag)tag).getAsInt());
+                    list.add(((NumericTag)tag).getAsInt()); // Scissors - Remove (T) cast
+                 }
+ 
+                 if (this.hasElementSeparator()) {
+@@ -257,7 +311,7 @@ public class TagParser {
+             }
+ 
+             this.expect(']');
+-            return list;
+            return (List<T>) list; // Scissors - Cast to List<T>
+         }
+     }
+