From 49225f5f0429da80e9fbed49fd705cda399a2da7 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Sat, 31 Dec 2016 18:11:19 -0800
Subject: [PATCH] We don't currently support blitting to < 8 bpp surfaces,
 return an error instead of corrupting memory in that case.

---
 src/video/SDL_blit.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/video/SDL_blit.c b/src/video/SDL_blit.c
index 90aa87898..b64f4cbf4 100644
--- a/src/video/SDL_blit.c
+++ b/src/video/SDL_blit.c
@@ -219,6 +219,12 @@ SDL_CalculateBlit(SDL_Surface * surface)
     SDL_BlitMap *map = surface->map;
     SDL_Surface *dst = map->dst;
 
+    /* We don't currently support blitting to < 8 bpp surfaces */
+    if (dst->format->BitsPerPixel < 8) {
+        SDL_InvalidateMap(map);
+        return SDL_SetError("Blit combination not supported");
+    }
+
     /* Clean everything out to start */
     if ((surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL) {
         SDL_UnRLESurface(surface, 1);