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[Qemu-devel] [PULL 4/4] cirrus: fix oob access issue (CVE-2017-2615)
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PULL 4/4] cirrus: fix oob access issue (CVE-2017-2615) |
Date: |
Thu, 2 Feb 2017 09:23:09 +0100 |
From: Li Qiang <address@hidden>
When doing bitblt copy in backward mode, we should minus the
blt width first just like the adding in the forward mode. This
can avoid the oob access of the front of vga's vram.
Signed-off-by: Li Qiang <address@hidden>
Reviewed-by: Laszlo Ersek <address@hidden>
Signed-off-by: Gerd Hoffmann <address@hidden>
Message-id: address@hidden
Message-id: address@hidden
{ kraxel: with backward blits (negative pitch) addr is the topmost
address, so check it as-is against vram size ]
Cc: address@hidden
Cc: P J P <address@hidden>
Cc: Laszlo Ersek <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: Wolfgang Bumiller <address@hidden>
Fixes: d3532a0db02296e687711b8cdc7791924efccea0 (CVE-2014-8106)
Signed-off-by: Gerd Hoffmann <address@hidden>
---
hw/display/cirrus_vga.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 7db6409..16f27e8 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -274,10 +274,9 @@ static bool blit_region_is_unsafe(struct CirrusVGAState *s,
{
if (pitch < 0) {
int64_t min = addr
- + ((int64_t)s->cirrus_blt_height-1) * pitch;
- int32_t max = addr
- + s->cirrus_blt_width;
- if (min < 0 || max > s->vga.vram_size) {
+ + ((int64_t)s->cirrus_blt_height - 1) * pitch
+ - s->cirrus_blt_width;
+ if (min < -1 || addr >= s->vga.vram_size) {
return true;
}
} else {
--
1.8.3.1
- [Qemu-devel] [PULL 0/4] cirrus: multiple bugfixes, including CVE-2017-2615 fix., Gerd Hoffmann, 2017/02/02
- [Qemu-devel] [PULL 4/4] cirrus: fix oob access issue (CVE-2017-2615),
Gerd Hoffmann <=
- [Qemu-devel] [PULL 1/4] cirrus: handle negative pitch in cirrus_invalidate_region(), Gerd Hoffmann, 2017/02/02
- [Qemu-devel] [PULL 3/4] cirrus: fix blit address mask handling, Gerd Hoffmann, 2017/02/02
- [Qemu-devel] [PULL 2/4] cirrus: allow zero source pitch in pattern fill rops, Gerd Hoffmann, 2017/02/02
- Re: [Qemu-devel] [PULL 0/4] cirrus: multiple bugfixes, including CVE-2017-2615 fix., Gerd Hoffmann, 2017/02/02