Bugzilla – Bug 889526
VUL-0: CVE-2014-5146,CVE-2014-5149: xen: XSA-97 Long latency virtual-mmu operations are not preemptible
Last modified: 2016-11-22 17:18:38 UTC
Xen Security Advisory XSA-97 Long latency virtual-mmu operations are not preemptible ISSUE DESCRIPTION ================= Some MMU virtualization operations on HVM guests must process every page assigned to a guest. For larger guests, this can tie up a vcpu for a significant amount of time, as the operations are not preemptible. IMPACT ====== A malicious HVM guest with a large allocation of shadow/p2m RAM can mount a denial of service attack affecting the whole system. VULNERABLE SYSTEMS ================== ARM systems are not vulnerable. All x86 Xen versions are vulnerable. The vulnerability is only exposed to HVM guests. In the default configuration, the vulnerability is only exposed to large guests (guests assigned more than 128Gbytes of memory). MITIGATION ========== Running only PV guests, or only smaller guests will avoid this problem. Since the vulnerability actually depends on the guest's shadow memory, if you are overriding the default allocation (which is about 0.5% of guest RAM) by using the "shadow_memory=" VM configuration file option, you should adjust your idea of a 'smaller' guest accordingly. RESOLUTION ========== For HAP-enabled guests, the attached patch resolves ths issue. HAP (Hardware Assisted Paging, aka nested paging) is enabled by default if the system is suitably capable. The VM configuration file can disable or enable HAP explicitly by setting "hap=0" or "hap=1". HAP can also be globally disabled by specifying "hap=off" on the hypervisor command line. There is no resolution for guests using shadow pagetables (i.e., not using HAP) at this time. xsa97-hap-unstable.patch xen-unstable xsa97-hap-4.4.patch Xen 4.4.x xsa97-hap-4.3.patch Xen 4.3.x xsa97-hap-4.2-prereq.patch, xsa97-hap-4.2.patch Xen 4.2.x $ sha256sum xsa97*.patch c9e0e9f136db1b976ea371be10430598a7f21b4a33b4849f2081566657ff5da1 xsa97-hap-4.2.patch c525a99263eed6f93fad685ae9dad1ae10c8930345ec52659211541640797bb5 xsa97-hap-4.2-prereq.patch cfab6521221a5058a0dfbb6d59c3c4cd0e7f4239bb6cbee2723de22c33caafda xsa97-hap-4.3.patch 138511f2fd8362366e09dda18443387886ec4397eecc1a2f6a7e85643bd415e8 xsa97-hap-4.4.patch 58c56daa01f20be0317700d383dfbba8de35695bd38a9860c0c0463181d76351 xsa97-hap-unstable.patch $ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAEBAgAGBQJT1nUMAAoJEIP+FMlX6CvZvHsH/1JfVSYHi9uQGnkQQLEKWvz6 2x4gt2D5o009ZiK42fHic51i5pF25lpaGQBXp5jv5IECok0Ko6YKX2ESJWkWjThO SRFikiKLzN2+1Aw0v6d/EFV0JE8QO7UjwBVdFCjUPInbXVzs7pAGXYbzV8275Niy nUJv85y9g7tOtLLdkG3sWzs0a6uamf1LLifx3hrQWPstR5NRNRxrFfgzKUhsoaQQ CabXJ7sMdP5hPlwV85OugXMzIVT70NHKKh1i307I3x3sPuvyrMrm6dJxxzV+ezHz gx9hDh4SiUZG0eB7LWi16g/yfvEyEDdGZJHCE7RwkaWoZg+AnW05ZHSg/dpiA4Q= =YRTW -----END PGP SIGNATURE-----
Created attachment 600299 [details] patch for hap-4.2
Created attachment 600301 [details] hap-4.2-prereq
Created attachment 600302 [details] hap-4.3
Created attachment 600303 [details] hap-4.4
Created attachment 600304 [details] hap-unstable
bugbot adjusting priority
I guess you're inquiring about the progress of this? The patches originally provided are making incorrect assumptions and hence need re-working (sadly none of the pre-disclosure list members, including us, noticed the problem, yet the upstream regression testing spotted the issue immediately after the patches went into the respective trees). Finding a solution turns out somewhat problematic (as to not cause other unintended side effects), and hence is taking some more time.
And the shadow mode side of this still didn't get addressed at all.
Affected packages: SLE-10-SP3-TERADATA: xen SLE-11-SP1-TERADATA: xen SLE-11-SP3: xen SLE-11-SP3-PRODUCTS: xen SLE-11-SP3-UPTU: xen
SUSE-SU-2015:0022-1: An update that solves 8 vulnerabilities and has 10 fixes is now available. Category: security (important) Bug References: 826717,866902,882089,889526,896023,897614,897906,898772,900292,901317,903357,903359,903850,903967,903970,905465,905467,906439 CVE References: CVE-2013-3495,CVE-2014-5146,CVE-2014-5149,CVE-2014-8594,CVE-2014-8595,CVE-2014-8866,CVE-2014-8867,CVE-2014-9030 Sources used: SUSE Linux Enterprise Software Development Kit 12 (src): xen-4.4.1_08-5.2 SUSE Linux Enterprise Server 12 (src): xen-4.4.1_08-5.2 SUSE Linux Enterprise Desktop 12 (src): xen-4.4.1_08-5.2
openSUSE-SU-2015:0226-1: An update that solves 11 vulnerabilities and has 5 fixes is now available. Category: security (important) Bug References: 826717,866902,882089,889526,900292,901317,903357,903359,903850,903967,903970,905465,905467,906439,906996,910681 CVE References: CVE-2013-3495,CVE-2014-5146,CVE-2014-5149,CVE-2014-8594,CVE-2014-8595,CVE-2014-8866,CVE-2014-8867,CVE-2014-9030,CVE-2014-9065,CVE-2014-9066,CVE-2015-0361 Sources used: openSUSE 13.1 (src): xen-4.3.3_04-34.1
11 seems not fixed yet
openSUSE-SU-2015:0256-1: An update that solves 11 vulnerabilities and has 9 fixes is now available. Category: security (important) Bug References: 826717,866902,882089,889526,896023,897906,898772,900292,901317,903357,903359,903850,903967,903970,904255,905465,905467,906439,906996,910681 CVE References: CVE-2013-3495,CVE-2014-5146,CVE-2014-5149,CVE-2014-8594,CVE-2014-8595,CVE-2014-8866,CVE-2014-8867,CVE-2014-9030,CVE-2014-9065,CVE-2014-9066,CVE-2015-0361 Sources used: openSUSE 13.2 (src): xen-4.4.1_08-9.1
An update workflow for this issue was started. This issue was rated as moderate. Please submit fixed packages until 2015-03-09. When done, reassign the bug to security-team@suse.de. https://swamp.suse.de/webswamp/wf/60766
The patches provided by upstream that address this issue have been taken and committed to all the relevant SLE and openSUSE branches. There have already been maintenance releases containing them on both SLE and openSUSE. As for the shadow mode side Jan mentioned in comment #11, upstream has decided not to address this issue at all. Said another way, the fixes currently provided are all the fixes expected for this bug. This bug may be closed.
released