From bf186d81b1ac66295d848cd32e376dfa9da3687e Mon Sep 17 00:00:00 2001
From: mckaygerhard <mckaygerhard@gmail.com>
Date: Sun, 2 Jun 2024 04:20:34 -0400
Subject: [PATCH] Avoid a crash in `drawMeshNode()` after reading out of array

* backported from https://github.com/MultiCraft/MultiCraft/commit/b201316aed364e51020b86603b8601f66dee6d4d
---
 src/client/content_mapblock.cpp | 9 +++++++--
 src/mapnode.cpp                 | 2 +-
 src/util/directiontables.cpp    | 8 ++++++++
 src/util/directiontables.h      | 2 +-
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/client/content_mapblock.cpp b/src/client/content_mapblock.cpp
index 4e900ac7c..3afe50d4f 100644
--- a/src/client/content_mapblock.cpp
+++ b/src/client/content_mapblock.cpp
@@ -1420,10 +1420,15 @@ void MapblockMeshGenerator::drawMeshNode()
 		// Convert wallmounted to 6dfacedir.
 		// When cache enabled, it is already converted.
 		facedir = n.getWallMounted(nodedef);
-		if (!enable_mesh_cache)
-			facedir = wallmounted_to_facedir[facedir];
+		if (!enable_mesh_cache) {
+			facedir = wallmountedToFacedir(facedir);
+		}
 	}
 
+	// f->mesh_ptr has 24 elements
+	if (facedir > 23)
+		facedir = 0;
+
 	if (!data->m_smooth_lighting && f->mesh_ptr[facedir]) {
 		// use cached meshes
 		private_mesh = false;
diff --git a/src/mapnode.cpp b/src/mapnode.cpp
index 57c0cb0bc..edb97db8e 100644
--- a/src/mapnode.cpp
+++ b/src/mapnode.cpp
@@ -151,7 +151,7 @@ u8 MapNode::getFaceDir(const NodeDefManager *nodemgr,
 		return (getParam2() & 0x1F) % 24;
 	if (allow_wallmounted && (f.param_type_2 == CPT2_WALLMOUNTED ||
 			f.param_type_2 == CPT2_COLORED_WALLMOUNTED))
-		return wallmounted_to_facedir[getParam2() & 0x07];
+		return wallmountedToFacedir(getParam2() & 0x07);
 	return 0;
 }
 
diff --git a/src/util/directiontables.cpp b/src/util/directiontables.cpp
index 9eb13b3e6..0579d6fb0 100644
--- a/src/util/directiontables.cpp
+++ b/src/util/directiontables.cpp
@@ -118,3 +118,11 @@ const u8 wallmounted_to_facedir[6] = {
 	8,
 	4 + 2
 };
+
+const u8 wallmountedToFacedir(u8 index)
+{
+	if (index > 5)
+		return 0;
+	else
+		return wallmounted_to_facedir[index];
+}
diff --git a/src/util/directiontables.h b/src/util/directiontables.h
index f3773b4ae..240fa5633 100644
--- a/src/util/directiontables.h
+++ b/src/util/directiontables.h
@@ -31,7 +31,7 @@ extern const v3s16 g_26dirs[26];
 // 26th is (0,0,0)
 extern const v3s16 g_27dirs[27];
 
-extern const u8 wallmounted_to_facedir[6];
+extern const u8 wallmountedToFacedir(u8 index);
 
 /// Direction in the 6D format. g_27dirs contains corresponding vectors.
 /// Here P means Positive, N stands for Negative.