OVMSA-2015-0096 - xen security update
| Type: | SECURITY |
| Severity: | IMPORTANT |
| Release Date: | 2015-07-27 |
Description
[4.1.3-25.el5.127.60]
- ide: Clear DRQ after handling all expected accesses
This is additional hardening against an end_transfer_func that fails to
clear the DRQ status bit. The bit must be unset as soon as the PIO
transfer has completed, so it's better to do this in a central place
instead of duplicating the code in all commands (and forgetting it in
some).
Signed-off-by: Kevin Wolf
This is XSA-138 CVE-2015-5154
Acked-by: Chuck Anderson
Reviewed-by: John Haxby
Tested-by: boris.ostrovsky@oracle.com
Tested-by: konrad.wilk@oracle.com [bug 21497210] {CVE-2015-5154}
[4.1.3-25.el5.127.59]
- ide: Check array bounds before writing to io_buffer
If the end_transfer_func of a command is called because enough data has
been read or written for the current PIO transfer, and it fails to
correctly call the command completion functions, the DRQ bit in the
status register and s->end_transfer_func may remain set. This allows the
guest to access further bytes in s->io_buffer beyond s->data_end, and
eventually overflowing the io_buffer.
One case where this currently happens is emulation of the ATAPI command
START STOP UNIT.
This patch fixes the problem by adding explicit array bounds checks
before accessing the buffer instead of relying on end_transfer_func to
function correctly.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf
This is XSA-138 CVE-2015-5154
Acked-by: Chuck Anderson
Reviewed-by: John Haxby
Tested-by: boris.ostrovsky@oracle.com
Tested-by: konrad.wilk@oracle.com [bug 21497210] {CVE-2015-5154}
[4.1.3-25.el5.127.58]
- tools: libxl: Explicitly disable graphics backends on qemu cmdline
By default qemu will try to create some sort of backend for the
emulated VGA device, either SDL or VNC.
However when the user specifies sdl=0 and vnc=0 in their configuration
libxl was not explicitly disabling either backend, which could lead to
one unexpectedly running.
If either sdl=1 or vnc=1 is configured then both before and after this
change only the backends which are explicitly enabled are configured,
i.e. this issue only occurs when all backends are supposed to have
been disabled.
This affects qemu-xen and qemu-xen-traditional differently.
If qemu-xen was compiled with SDL support then this would result in an
SDL window being opened if is valid, or a failure to start
the guest if not. Passing '-display none' to qemu before any further
-sdl options disables this default behaviour and ensures that SDL is
only started if the libxl configuration demands it.
If qemu-xen was compiled without SDL support then qemu would instead
start a VNC server listening on ::1 (IPv6 localhost) or 127.0.0.1
(IPv4 localhost) with IPv6 preferred if available. Explicitly pass
'-vnc none' when vnc is not enabled in the libxl configuration to
remove this possibility.
qemu-xen-traditional would never start a vnc backend unless asked.
However by default it will start an SDL backend, the way to disable
this is to pass a -vnc option. In other words passing '-vnc none' will
disable both vnc and sdl by default. sdl can then be reenabled if
configured by subsequent use of the -sdl option.
Tested with both qemu-xen and qemu-xen-traditional built with SDL
support and:
xl cr # defaults
xl cr sdl=0 vnc=0
xl cr sdl=1 vnc=0
xl cr sdl=0 vnc=1
xl cr sdl=0 vnc=0 vga='none'
xl cr sdl=0 vnc=0 nographic=1
with both valid and invalid .
This is XSA-119 / CVE-2015-2152.
Reported-by: Sander Eikelenboom
Signed-off-by: Ian Campbell
Acked-by: Ian Jackson
Signed-off-by: Zhenzhong Duan [bug 20968962] {CVE-2015-2152}
[4.1.3-25.el5.127.57]
- x86emul: enforce privilege level restrictions when loading CS
Privilege level checks were basically missing for the CS case, the
only check that was done (RPL == DPL for nonconforming segments)
was solely covering a single special case (return to non-conforming
segment).
Additionally in long mode the L bit set requires the D bit to be clear,
as was recently pointed out for KVM by Nadav Amit
.
Finally we also need to force the loaded selector's RPL to CPL (at
least as long as lret/retf emulation doesn't support privilege level
changes).
This is CVE-2014-8595 / XSA-110.
Signed-off-by: Jan Beulich
Reviewed-by: Tim Deegan
master commit: 1d68c1a70e00ed95ef0889cfa005379dab27b37d
master date: 2014-11-18 14:16:23 +0100
Signed-off-by: Zhenzhong Duan
Reviewed-by: Konrad Rzeszutek Wilk [bug 20361745] {CVE-2014-8595}
[4.1.3-25.el5.127.56]
- AMD/intremap: Prevent use of per-device vector maps until irq logic is fixed
XSA-36 changed the default vector map mode from global to per-device. This is
because a global vector map does not prevent one PCI device from impersonating
another and launching a DoS on the system.
However, the per-device vector map logic is broken for devices with multiple
MSI-X vectors, which can either result in a failed ASSERT() or misprogramming
of a guests interrupt remapping tables. The core problem is not trivial to
fix.
In an effort to get AMD systems back to a non-regressed state, introduce a new
type of vector map called per-device-global. This uses per-device vector maps
in the IOMMU, but uses a single used_vector map for the core IRQ logic.
This patch is intended to be removed as soon as the per-device logic is fixed
correctly.
Signed-off-by: Andrew Cooper
Acked-by: Suravee Suthikulpanit
Signed-off-by: Zhenzhong Duan
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Boris Ostrovsky
This patch fix bug introduced by xsa36.patch [bug 19288706]
[4.1.3-25.el5.127.55]
- x86: fix ordering of operations in destroy_irq()
The fix for XSA-36, switching the default of vector map management to
be per-device, exposed more readily a problem with the cleanup of these
vector maps: dynamic_irq_cleanup() clearing desc->arch.used_vectors
keeps the subsequently invoked clear_irq_vector() from clearing the
bits for both the in-use and a possibly still outstanding old vector.
Fix this by folding dynamic_irq_cleanup() into destroy_irq(), which was
its only caller, deferring the clearing of the vector map pointer until
after clear_irq_vector().
Once at it, also defer resetting of desc->handler until after the loop
around smp_mb() checking for IRQ_INPROGRESS to be clear, fixing a
(mostly theoretical) issue with the intercation with do_IRQ(): If we
don't defer the pointer reset, do_IRQ() could, for non-guest IRQs, call
->ack() and ->end() with different ->handler pointers, potentially
leading to an IRQ remaining un-acked. The issue is mostly theoretical
because non-guest IRQs are subject to destroy_irq() only on (boot time)
error paths.
As to the changed locking: Invoking clear_irq_vector() with desc->lock
held is okay because vector_lock already nests inside desc->lock (proven
by set_desc_affinity(), which takes vector_lock and gets called from
various desc->handler->ack implementations, getting invoked with
desc->lock held).
Reported-by: Andrew Cooper
Signed-off-by: Jan Beulich
Acked-by: Keir Fraser
Reviewed-by: Andrew Cooper
Acked-by: George Dunlap
Signed-off-by: Zhenzhong Duan
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Boris Ostrovsky
This patch fix bug introduced by xsa36.patch [bug 19288706]
[4.1.3-25.el5.127.54]
- AMD IOMMU: allow disabling only interrupt remapping when certain IVRS consistency checks fail
After some more thought on the XSA-36 and specifically the comments we
got regarding disabling the IOMMU in this situation altogether making
things worse instead of better, I came to the conclusion that we can
actually restrict the action in affected cases to just disabling
interrupt remapping. That doesn't make the situation worse than prior
to the XSA-36 fixes (where interrupt remapping didn't really protect
domains from one another), but allows at least DMA isolation to still
be utilized.
To do so, disabling of interrupt remapping must be explicitly requested
on the command line - respective checks will then be skipped.
Signed-off-by: Jan Beulich
Acked-by: Suravee Suthikulanit
Signed-off-by: Zhenzhong Duan
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Boris Ostrovsky
This patch fix bug introduced by xsa36.patch [bug 19288706]
[4.1.3-25.el5.127.53]
- AMD IOMMU: also spot missing IO-APIC entries in IVRS table
Apart from dealing duplicate conflicting entries, we also have to
handle firmware omitting IO-APIC entries in IVRS altogether. Not doing
so has resulted in c/s 26517:601139e2b0db to crash such systems during
boot (whereas with the change here the IOMMU gets disabled just as is
being done in the other cases, i.e. unless global tables are being
used).
Debugging this issue has also pointed out that the debug log output is
pretty ugly to look at - consolidate the output, and add one extra
item for the IVHD special entries, so that future issues are easier
to analyze.
Signed-off-by: Jan Beulich
Tested-by: Sander Eikelenboom
Acked-by: Ian Campbell
xen-unstable changeset: 26531:e68f14b9e739
xen-unstable date: Thu Feb 14 08:40:52 UTC 2013
Signed-off-by: Zhenzhong Duan
Reviewed-by: Konrad Rzeszutek Wilk
Reviewed-by: Boris Ostrovsky
This patch applies on top of xsa36.patch which is version 3 of the
xen.org 4.1 patch already applied to OVM 3 [bug 19288706]
Related CVEs
Updated Packages
| Release/Architecture | Filename | MD5sum | Superseded By Advisory |
|
| Oracle VM 3.2 (x86_64) | xen-4.1.3-25.el5.127.60.src.rpm | 0b758b60684a955849f919b5fc56fec5 | OVMSA-2021-0014 |
| xen-4.1.3-25.el5.127.60.x86_64.rpm | 81cb4fa0bca5d26ddb2190e8defd224d | OVMSA-2021-0014 |
| xen-devel-4.1.3-25.el5.127.60.x86_64.rpm | 4ab674d74196b7f57353f20414b27efd | OVMSA-2019-0048 |
| xen-tools-4.1.3-25.el5.127.60.x86_64.rpm | 39fe36d0365e525356f7e781575d1337 | OVMSA-2021-0014 |
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