Bug 1346981

Summary:	Regression from CVE-2016-3712: windows installer fails to start [rhel-6.9]
Product:	Red Hat Enterprise Linux 6	Reporter:	Ademar Reis <areis>
Component:	qemu-kvm	Assignee:	Gerd Hoffmann <kraxel>
Status:	CLOSED ERRATA	QA Contact:	Guo, Zhiyi <zhguo>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.8	CC:	chayang, jen, jherrman, juzhang, kraxel, mgoldboi, mkenneth, rbalakri, virt-bugs, virt-maint
Target Milestone:	rc	Keywords:	Regression, ZStream
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu-kvm-0.12.1.2-2.492.el6	Doc Type:	Bug Fix
Doc Text:	After applying the fix for security issue CVE-2016-3712, the installation of certain guests on Red Hat Enterprise Linux was not possible due to unmodifiable registers. This update introduces a new register set to be used instead of vga registers in these guests. As a result, the vga registers no longer cause the guest installation to fail.	Story Points:	---
Clone Of:	1346976
Clones:	1347190 1347191 1347192 (view as bug list)		Environment:
Last Closed:	2017-03-21 09:38:56 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1346976, 1346982
Bug Blocks:	1347190, 1347191, 1347192

Description Ademar Reis 2016-06-15 18:15:25 UTC

+++ This bug was initially created as a clone of Bug #1346976 +++

The fix for CVE-2016-3712 introduced a regression and we'll have to push a new update.

From the upstream patch:

"""
From: Gerd Hoffmann <kraxel>
Subject: [Qemu-devel] [PATCH] vga: add sr_vbe register set

Commit "fd3c136 vga: make sure vga register setup for vbe stays intact
(CVE-2016-3712)." causes a regression.  The win7 installer is unhappy
because it can't freely modify vga registers any more while in vbe mode.

This patch introduces a new sr_vbe register set.  The vbe_update_vgaregs
will fill sr_vbe[] instead of sr[].  Normal vga register reads and
writes go to sr[].  Any sr register read access happens through a new
sr() helper function which will read from sr_vbe[] with vbe active and
from sr[] otherwise.

This way we can allow guests update sr[] registers as they want, without
allowing them disrupt vbe video modes that way.

Reported-by: Thomas Lamprecht <thomas>
Signed-off-by: Gerd Hoffmann <kraxel>
"""

Comment 3 Jeff Nelson 2016-06-30 18:34:05 UTC

Fix included in qemu-kvm-0.12.1.2-2.492.el6

Comment 5 Guo, Zhiyi 2016-11-28 06:57:51 UTC

eproduced on 6.9.z host with
kernel: 2.6.32-671.el6.x86_64
qemu: qemu-kvm-rhev-0.12.1.2-2.491.el6_8.1.x86_64

Trying to install win7/win2008r2 guests, results:

iso:en_windows_7_ultimate_with_sp1_x86_dvd_u_677460.iso result: stuck at "starting windows"
iso:en_windows_7_ultimate_with_sp1_x64_dvd_u_677332.iso result: stuck at "starting windows" 
iso:en_windows_server_2008_r2_standard_enterprise_datacenter_and_web_with_sp1_x64_dvd_617601.iso result: stuck at "starting windows" 

Install win10 guests for comparing, win10 guests install and work well, isos used:
en_windows_10_enterprise_version_1607_updated_jul_2016_x64_dvd_9054264.iso
en_windows_10_enterprise_version_1607_updated_jul_2016_x86_dvd_9060097.iso

Verify against qemu-kvm-0.12.1.2-2.496.el6.x86_64

Both windows7/win2008r2 guests install and work well.
Install win10 guests for comparing, win10 guests install and work well also.

Comment 6 Guo, Zhiyi 2016-11-28 06:58:40 UTC

Per comment 5, move to verified

Comment 8 errata-xmlrpc 2017-03-21 09:38:56 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2017-0621.html