From: Sam Lantinga <slouken@libsdl.org>
Date: Tue, 30 Nov 2021 12:36:46 -0800
Subject: Always create a full 256-entry map in case color values are out of
 range

Bug: https://github.com/libsdl-org/SDL/issues/5042
Bug-CVE: CVE-2021-33657
Bug-Debian: https://bugs.debian.org/1014577
Origin: upstream, 2.0.20, commit:8c91cf7dba5193f5ce12d06db1336515851c9ee9
---
 src/video/SDL_pixels.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/video/SDL_pixels.c b/src/video/SDL_pixels.c
index 17f1a71..38de650 100644
--- a/src/video/SDL_pixels.c
+++ b/src/video/SDL_pixels.c
@@ -477,7 +477,7 @@ static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical)
 		}
 		*identical = 0;
 	}
-	map = (Uint8 *)SDL_malloc(src->ncolors);
+	map = (Uint8 *)SDL_calloc(256, sizeof(Uint8));
 	if ( map == NULL ) {
 		SDL_OutOfMemory();
 		return(NULL);
@@ -498,7 +498,7 @@ static Uint8 *Map1toN(SDL_PixelFormat *src, SDL_PixelFormat *dst)
 	SDL_Palette *pal = src->palette;
 
 	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
-	map = (Uint8 *)SDL_malloc(pal->ncolors*bpp);
+	map = (Uint8 *)SDL_calloc(256, bpp);
 	if ( map == NULL ) {
 		SDL_OutOfMemory();
 		return(NULL);