Fixed bug 4500 - Heap-Buffer Overflow in Map1toN pertaining to SDL_pixels.c
Petr Pisar
The reproducer has these data in BITMAPINFOHEADER:
biSize = 40
biBitCount = 8
biClrUsed = 131075
SDL_LoadBMP_RW() function passes biBitCount as a color depth to SDL_CreateRGBSurface(), thus 256-color pallete is allocated. But then biClrUsed colors are read from a file and stored into the palette. SDL_LoadBMP_RW should report an error if biClrUsed is greater than 2^biBitCount.
diff --git a/src/video/SDL_bmp.c b/src/video/SDL_bmp.c
index 908b77c..5974414 100644
--- a/src/video/SDL_bmp.c
+++ b/src/video/SDL_bmp.c
@@ -313,6 +313,10 @@
SDL_assert(biBitCount <= 8);
if (biClrUsed == 0) {
biClrUsed = 1 << biBitCount;
+ } else if (biClrUsed > (1 << biBitCount)) {
+ SDL_SetError("BMP file has an invalid number of colors");
+ was_error = SDL_TRUE;
+ goto done;
}
if ((int) biClrUsed > palette->ncolors) {
SDL_Color *colors;
