tr2/level: perform check on sprite texture count

This ensures we do not exceed the allocated sprite texture limit when
reading a level.

Resolves #2338.

docs/tr2/CHANGELOG.md

@@ -19,6 +19,7 @@
 - fixed Lara never stepping backwards off a step using her right foot (#1602)
 - fixed blood spawning on Lara from gunshots using incorrect positioning data (#2253)
 - fixed ghost meshes appearing near statics in custom levels (#2310)
+- fixed potential memory corruption when reading a custom level with more than 512 sprite textures (#2338)
 - fixed Lara activating triggers one frame too early (#2205, regression from 0.7)
 - fixed savegame incompatibility with OG (#2271, regression from 0.8)
 - fixed stopwatch showing wrong UI in some circumstances (#2221, regression from 0.8)

src/tr2/game/level.c

@@ -344,6 +344,9 @@ static void M_LoadSprites(VFILE *const file)
     BENCHMARK *const benchmark = Benchmark_Start();
     const int32_t num_textures = VFile_ReadS32(file);
     LOG_DEBUG("sprite textures: %d", num_textures);
+    if (num_textures > MAX_SPRITE_TEXTURES) {
+        Shell_ExitSystem("Too many sprite textures in level");
+    }
     for (int32_t i = 0; i < num_textures; i++) {
         SPRITE_TEXTURE *const sprite = &g_SpriteTextures[i];
         sprite->tex_page = VFile_ReadU16(file);

src/tr2/global/const.h

@@ -30,6 +30,7 @@
 #define MAX_CD_TRACKS 64
 #define MAX_TEXTURE_PAGES 32
 #define MAX_OBJECT_TEXTURES 2048
+#define MAX_SPRITE_TEXTURES 512
 #define MAX_PALETTES 16
 #define MAX_ROOMS 1024
 #define MAX_ROOMS_TO_DRAW 100

src/tr2/global/vars.c

@@ -29,7 +29,7 @@ bool g_GymInvOpenEnabled = true; // TODO: make me configurable
 int32_t g_MidSort = 0;
 GOURAUD_ENTRY g_GouraudTable[256];
 int32_t g_PhdWinTop;
-SPRITE_TEXTURE g_SpriteTextures[512];
+SPRITE_TEXTURE g_SpriteTextures[MAX_SPRITE_TEXTURES];
 int32_t g_LsAdder;
 float g_FltWinBottom;
 float g_FltResZBuf;

src/tr2/global/vars.h

@@ -27,7 +27,7 @@ extern bool g_GymInvOpenEnabled;
 extern int32_t g_MidSort;
 extern GOURAUD_ENTRY g_GouraudTable[256];
 extern int32_t g_PhdWinTop;
-extern SPRITE_TEXTURE g_SpriteTextures[];
+extern SPRITE_TEXTURE g_SpriteTextures[MAX_SPRITE_TEXTURES];
 extern int32_t g_LsAdder;
 extern float g_FltWinBottom;
 extern float g_FltResZBuf;