blob: 3910fb98a301ab2e9cf379b13838eff20fd12a1a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
From fc8e94c3e5e74437c4e73a5582f17cfd4cae5ccf Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 8 Feb 2017 11:18:36 +0100
Subject: [PATCH] cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo
(CVE-2017-2620)
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.
CVE: CVE-2017-2620
Upstream-Status: Backport
Cc: qemu-stable@nongnu.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 92f2b88cea48c6aeba8de568a45f2ed958f3c298)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.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 629a5c8..6766349 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -873,6 +873,10 @@ 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];
@@ -898,6 +902,10 @@ 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);
--
1.9.1
|
