OVMSA-2015-0095 - xen security update
| Type: | SECURITY |
| Severity: | IMPORTANT |
| Release Date: | 2015-07-27 |
Description
[4.3.0-55.el6.47.39]
- 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 [bug 21497187] {CVE-2015-5154}
[4.3.0-55.el6.47.38]
- ide/atapi: Fix START STOP UNIT command completion
The command must be completed on all code paths. START STOP UNIT with
pwrcnd set should succeed without doing anything.
Signed-off-by: Kevin Wolf
This is XSA-138 CVE-2015-5154
Acked-by: Chuck Anderson [bug 21497187] {CVE-2015-5154}
[4.3.0-55.el6.47.37]
- ide: Check array bounds before writing to io_buffer
(CVE-2015-5154)
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 21497187] {CVE-2015-5154}
[4.3.0-55.el6.47.36]
- 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 21497187] {CVE-2015-5154}
[4.3.0-55.el6.47.35]
- 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 21497187] {CVE-2015-5154}
[4.3.0-55.el6.47.34]
- 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
Reviewed-by: John Haxby [bug 21249563] {CVE-2015-2152}
Related CVEs
Updated Packages
| Release/Architecture | Filename | MD5sum | Superseded By Advisory |
|
| Oracle VM 3.3 (x86_64) | xen-4.3.0-55.el6.47.39.src.rpm | 62eb64c6052813f0443a7e8a9f6d1f31 | OVMSA-2021-0014 |
| xen-4.3.0-55.el6.47.39.x86_64.rpm | ae8f2903ac18e5d68ffb019ac5e2bbc2 | OVMSA-2021-0014 |
| xen-tools-4.3.0-55.el6.47.39.x86_64.rpm | f2fee4f4dc609c2985f83736bfdf78c2 | OVMSA-2021-0014 |
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