From 215902d7b6fb50c6fc216fc74f770858278ed904 Mon Sep 17 00:00:00 2001
From: hangaohuai <hangaohuai@huawei.com>
Date: Tue, 14 Mar 2017 14:39:19 +0800
Subject: [PATCH] fix :cirrus_vga fix OOB read case qemu Segmentation fault

check the validity of parameters in cirrus_bitblt_rop_fwd_transp_xxx
and cirrus_bitblt_rop_fwd_xxx to avoid the OOB read which causes qemu Segmentation fault.

After the fix, we will touch the assert in
cirrus_invalidate_region:
assert(off_cur_end >= off_cur);

Signed-off-by: fangying <fangying1@huawei.com>
Signed-off-by: hangaohuai <hangaohuai@huawei.com>
Message-id: 20170314063919.16200-1-hangaohuai@huawei.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/cirrus_vga_rop.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/cirrus_vga_rop.h b/hw/cirrus_vga_rop.h
index 0925a00..b7447f8 100644
--- a/hw/cirrus_vga_rop.h
+++ b/hw/cirrus_vga_rop.h
@@ -97,6 +97,11 @@ glue(glue(cirrus_bitblt_rop_fwd_transp_, ROP_NAME),_8)(CirrusVGAState *s,
     src = src_ - src_base;
     dstpitch -= bltwidth;
     srcpitch -= bltwidth;
+
+    if (bltheight > 1 && (dstpitch < 0 || srcpitch < 0)) {
+        return;
+    }
+
     for (y = 0; y < bltheight; y++) {
         for (x = 0; x < bltwidth; x++) {
 	    p = *(dst_base + m(dst));
@@ -143,6 +148,11 @@ glue(glue(cirrus_bitblt_rop_fwd_transp_, ROP_NAME),_16)(CirrusVGAState *s,
     src = src_ - src_base;
     dstpitch -= bltwidth;
     srcpitch -= bltwidth;
+
+    if (bltheight > 1 && (dstpitch < 0 || srcpitch < 0)) {
+        return;
+    }
+
     for (y = 0; y < bltheight; y++) {
         for (x = 0; x < bltwidth; x+=2) {
 	    p1 = *(dst_base + m(dst));
-- 
1.8.3.1