1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
2 From: Gerd Hoffmann <kraxel@redhat.com>
3 Date: Wed, 11 Oct 2017 10:43:14 +0200
4 Subject: [PATCH] cirrus: fix oob access in mode4and5 write functions
6 Move dst calculation into the loop, so we apply the mask on each
7 interation and will not overflow vga memory.
9 Cc: Prasad J Pandit <pjp@fedoraproject.org>
10 Reported-by: Niu Guoxiang <niuguoxiang@huawei.com>
11 Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
12 Message-id: 20171011084314.21752-1-kraxel@redhat.com
14 hw/display/cirrus_vga.c | 6 ++----
15 1 file changed, 2 insertions(+), 4 deletions(-)
17 diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
18 index afc290ab91..077a8cb74f 100644
19 --- a/hw/display/cirrus_vga.c
20 +++ b/hw/display/cirrus_vga.c
21 @@ -2038,15 +2038,14 @@ static void cirrus_mem_writeb_mode4and5_8bpp(CirrusVGAState * s,
22 unsigned val = mem_value;
25 - dst = s->vga.vram_ptr + (offset &= s->cirrus_addr_mask);
26 for (x = 0; x < 8; x++) {
27 + dst = s->vga.vram_ptr + ((offset + x) & s->cirrus_addr_mask);
29 *dst = s->cirrus_shadow_gr1;
30 } else if (mode == 5) {
31 *dst = s->cirrus_shadow_gr0;
36 memory_region_set_dirty(&s->vga.vram, offset, 8);
38 @@ -2060,8 +2059,8 @@ static void cirrus_mem_writeb_mode4and5_16bpp(CirrusVGAState * s,
39 unsigned val = mem_value;
42 - dst = s->vga.vram_ptr + (offset &= s->cirrus_addr_mask);
43 for (x = 0; x < 8; x++) {
44 + dst = s->vga.vram_ptr + ((offset + 2 * x) & s->cirrus_addr_mask & ~1);
46 *dst = s->cirrus_shadow_gr1;
47 *(dst + 1) = s->vga.gr[0x11];
48 @@ -2070,7 +2069,6 @@ static void cirrus_mem_writeb_mode4and5_16bpp(CirrusVGAState * s,
49 *(dst + 1) = s->vga.gr[0x10];
54 memory_region_set_dirty(&s->vga.vram, offset, 16);