Bug 1346982 – Regression from CVE-2016-3712: windows installer fails to start [rhel-7.3]

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Bug 1346982 - Regression from CVE-2016-3712: windows installer fails to start [rhel-7.3]

Summary:	Regression from CVE-2016-3712: windows installer fails to start [rhel-7.3]

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	qemu-kvm (Show other bugs)
Sub Component:
Version:	7.2
Hardware:	Unspecified Unspecified

Priority	unspecified Severity unspecified
Target Milestone:	rc
Target Release:	---
Assigned To:	Gerd Hoffmann
QA Contact:	Guo, Zhiyi
Docs Contact:

URL:
Whiteboard:
Keywords:	Regression, ZStream

Depends On:	1346976
Blocks:	1346981 1347527
	Show dependency tree / graph

Reported:	2016-06-15 14:19 EDT by Ademar Reis
Modified:	2016-11-03 16:14 EDT (History)
CC List:	9 users (show)

See Also:
Fixed In Version:	qemu-kvm-1.5.3-115.el7
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:	1347527 (view as bug list)
Environment:
Last Closed:	2016-11-03 16:14:34 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2016:2585	normal	SHIPPED_LIVE	Moderate: qemu-kvm security, bug fix, and enhancement update	2016-11-03 08:09:03 EDT

Groups: None (edit)

Description Ademar Reis 2016-06-15 14:19:13 EDT

+++ 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@redhat.com>
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@lamprecht.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
"""

Comment 1 Gerd Hoffmann 2016-06-16 11:30:55 EDT

backport posted.

Comment 3 Miroslav Rezanina 2016-06-20 03:35:42 EDT

Fix included in qemu-kvm-1.5.3-115.el7

Comment 5 Guo, Zhiyi 2016-08-30 06:18:02 EDT

Reproduced on 7.3 host with
kernel: 3.10.0-493.el7.x86_64
qemu:qemu-kvm-1.5.3-114.el7.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_x64_dvd_6851151.iso
en_windows_10_enterprise_x86_dvd_6851156.iso

Verify against qemu-kvm-1.5.3-122.el7.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 2016-08-31 03:34:55 EDT

Move to verified per comment 5

Comment 8 errata-xmlrpc 2016-11-03 16:14:34 EDT

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-2016-2585.html

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