53 lines
1.7 KiB
Diff
53 lines
1.7 KiB
Diff
From d775c497a84a5c4be3f15cca85ca8440dd5880a0 Mon Sep 17 00:00:00 2001
|
|
From: Gerd Hoffmann <kraxel@redhat.com>
|
|
Date: Wed, 22 Feb 2017 13:42:31 +0100
|
|
Subject: [PATCH qemu] cirrus: add blit_is_unsafe call to
|
|
cirrus_bitblt_cputovideo (CVE-2017-2620)
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
CIRRUS_BLTMODE_MEMSYSSRC blits do NOT check blit destination
|
|
and blit width, at all. Oops. Fix it.
|
|
|
|
Security impact: high.
|
|
|
|
The missing blit destination check allows to write to host memory.
|
|
Basically same as CVE-2014-8106 for the other blit variants.
|
|
|
|
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
|
|
Message-id: 1487679663-3264-1-git-send-email-kraxel@redhat.com
|
|
---
|
|
hw/display/cirrus_vga.c | 8 ++++++++
|
|
1 file changed, 8 insertions(+)
|
|
|
|
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
|
|
index 1deb520..b9e7cb1 100644
|
|
--- a/hw/display/cirrus_vga.c
|
|
+++ b/hw/display/cirrus_vga.c
|
|
@@ -900,6 +900,10 @@ static int cirrus_bitblt_cputovideo(CirrusVGAState * s)
|
|
{
|
|
int w;
|
|
|
|
+ if (blit_is_unsafe(s, true)) {
|
|
+ return 0;
|
|
+ }
|
|
+
|
|
s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_MEMSYSSRC;
|
|
s->cirrus_srcptr = &s->cirrus_bltbuf[0];
|
|
s->cirrus_srcptr_end = &s->cirrus_bltbuf[0];
|
|
@@ -925,6 +929,10 @@ static int cirrus_bitblt_cputovideo(CirrusVGAState * s)
|
|
}
|
|
s->cirrus_srccounter = s->cirrus_blt_srcpitch * s->cirrus_blt_height;
|
|
}
|
|
+
|
|
+ /* the blit_is_unsafe call above should catch this */
|
|
+ assert(s->cirrus_blt_srcpitch <= CIRRUS_BLTBUFSIZE);
|
|
+
|
|
s->cirrus_srcptr = s->cirrus_bltbuf;
|
|
s->cirrus_srcptr_end = s->cirrus_bltbuf + s->cirrus_blt_srcpitch;
|
|
cirrus_update_memory_access(s);
|
|
--
|
|
2.1.4
|
|
|