macfb: fix overflow of color_palette array

The palette_current index counter has a maximum size of 256 * 3 to cover a full
color palette of 256 RGB entries. Linux assumes that the palette_current index
wraps back around to zero after writing 256 RGB entries so ensure that
palette_current is reset at this point to prevent data corruption within
MacfbState.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211007221253.29024-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Mark Cave-Ayland
2021-10-08 13:31:03 +02:00
committed by Laurent Vivier
parent 906c2323f1
commit 14d0ddfce7
+3 -1
View File
@@ -303,7 +303,9 @@ static void macfb_ctrl_write(void *opaque,
s->palette_current = 0;
break;
case DAFB_LUT:
s->color_palette[s->palette_current++] = val;
s->color_palette[s->palette_current] = val;
s->palette_current = (s->palette_current + 1) %
ARRAY_SIZE(s->color_palette);
if (s->palette_current % 3) {
macfb_invalidate_display(s);
}