From ec949840b275a249d68cbb3ee5247997e75aa0fe Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Wed, 1 Apr 2020 21:30:25 +0100
Subject: [PATCH] Do not crash on failure to decompress region chunks this
 could happen when a chunk was partially overwritten with one of the same
 sector size.

---
 src/pocketmine/level/format/io/region/Anvil.php    | 7 ++++++-
 src/pocketmine/level/format/io/region/McRegion.php | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/pocketmine/level/format/io/region/Anvil.php b/src/pocketmine/level/format/io/region/Anvil.php
index d602fd8a2..6464269cf 100644
--- a/src/pocketmine/level/format/io/region/Anvil.php
+++ b/src/pocketmine/level/format/io/region/Anvil.php
@@ -33,6 +33,7 @@ use pocketmine\nbt\tag\ByteArrayTag;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\nbt\tag\IntArrayTag;
 use pocketmine\nbt\tag\ListTag;
+use function zlib_decode;
 
 class Anvil extends McRegion{
 
@@ -96,8 +97,12 @@ class Anvil extends McRegion{
 	}
 
 	protected function nbtDeserialize(string $data) : Chunk{
+		$data = @zlib_decode($data);
+		if($data === false){
+			throw new CorruptedChunkException("Failed to decompress chunk data");
+		}
 		$nbt = new BigEndianNBTStream();
-		$chunk = $nbt->readCompressed($data);
+		$chunk = $nbt->read($data);
 		if(!($chunk instanceof CompoundTag) or !$chunk->hasTag("Level")){
 			throw new CorruptedChunkException("'Level' key is missing from chunk NBT");
 		}
diff --git a/src/pocketmine/level/format/io/region/McRegion.php b/src/pocketmine/level/format/io/region/McRegion.php
index 3516fc598..946ee5170 100644
--- a/src/pocketmine/level/format/io/region/McRegion.php
+++ b/src/pocketmine/level/format/io/region/McRegion.php
@@ -58,6 +58,7 @@ use function strrpos;
 use function substr;
 use function time;
 use function unpack;
+use function zlib_decode;
 use const SCANDIR_SORT_NONE;
 
 class McRegion extends BaseLevelProvider{
@@ -125,8 +126,12 @@ class McRegion extends BaseLevelProvider{
 	 * @throws CorruptedChunkException
 	 */
 	protected function nbtDeserialize(string $data) : Chunk{
+		$data = @zlib_decode($data);
+		if($data === false){
+			throw new CorruptedChunkException("Failed to decompress chunk data");
+		}
 		$nbt = new BigEndianNBTStream();
-		$chunk = $nbt->readCompressed($data);
+		$chunk = $nbt->read($data);
 		if(!($chunk instanceof CompoundTag) or !$chunk->hasTag("Level")){
 			throw new CorruptedChunkException("'Level' key is missing from chunk NBT");
 		}