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From: Laurent Vivier <laurent@vivier.eu>
To: qemu-devel@nongnu.org
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>,
	Laurent Vivier <laurent@vivier.eu>
Subject: [PULL 04/13] macfb: fix overflow of color_palette array
Date: Fri,  8 Oct 2021 13:45:09 +0200	[thread overview]
Message-ID: <20211008114518.757615-5-laurent@vivier.eu> (raw)
In-Reply-To: <20211008114518.757615-1-laurent@vivier.eu>

From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

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>
---
 hw/display/macfb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/display/macfb.c b/hw/display/macfb.c
index b363bab8896a..39dab49026c3 100644
--- a/hw/display/macfb.c
+++ b/hw/display/macfb.c
@@ -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);
         }
-- 
2.31.1



  parent reply	other threads:[~2021-10-08 11:52 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-08 11:45 [PULL 00/13] M68k next patches Laurent Vivier
2021-10-08 11:45 ` [PULL 01/13] macfb: handle errors that occur during realize Laurent Vivier
2021-10-08 11:45 ` [PULL 02/13] macfb: update macfb.c to use the Error API best practices Laurent Vivier
2021-10-08 11:45 ` [PULL 03/13] macfb: fix invalid object reference in macfb_common_realize() Laurent Vivier
2021-10-08 11:45 ` Laurent Vivier [this message]
2021-10-08 11:45 ` [PULL 05/13] macfb: use memory_region_init_ram() in macfb_common_realize() for the framebuffer Laurent Vivier
2021-10-08 11:45 ` [PULL 06/13] macfb: add trace events for reading and writing the control registers Laurent Vivier
2021-10-08 11:45 ` [PULL 07/13] macfb: implement mode sense to allow display type to be detected Laurent Vivier
2021-10-08 11:45 ` [PULL 08/13] macfb: add qdev property to specify display type Laurent Vivier
2021-10-08 11:45 ` [PULL 09/13] macfb: add common monitor modes supported by the MacOS toolbox ROM Laurent Vivier
2021-11-05 15:56   ` Peter Maydell
2021-11-05 16:43     ` Laurent Vivier
2021-10-08 11:45 ` [PULL 10/13] macfb: fix up 1-bit pixel encoding Laurent Vivier
2021-10-08 11:45 ` [PULL 11/13] macfb: fix 24-bit RGB " Laurent Vivier
2021-10-08 11:45 ` [PULL 12/13] macfb: add vertical blank interrupt Laurent Vivier
2021-10-08 11:45 ` [PULL 13/13] q800: wire macfb IRQ to separate video interrupt on VIA2 Laurent Vivier
2021-10-08 13:29 ` [PULL 00/13] M68k next patches Richard Henderson

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