Re: [Qemu-devel] [PATCH] vga: stop passing pointers to vga_draw_line* functions

[Eric Blake <eblake@redhat.com>]

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On 08/24/2017 04:19 AM, Gerd Hoffmann wrote:
> Instead pass around the address (aka offset into vga memory).
> Add vga_read_* helper functions which apply vbe_size_mask to
> the address, to make sure the address stays within the valid
> range, simliar to the cirrus blitter fixes (commits ffaf857778

s/simliar/similar/

> and 026aeffcb4).
> 
> Impact:  DoS for priviledged guest users.  qemu crashes with

s/priviledged/privileged/

> a segfault, when hitting the guard page after vga memory
> allocation, while reading vga memory for display updates.
> 
> Fixes: CVE-2017-xxxx

Do we have the actual number? Are we trying to get this in 2.10-rc4, or
is it merely 2.11 + qemu-stable (2.10.1) material?

> Cc: P J P <ppandit@redhat.com>
> Reported-by: David Buchanan <d@vidbuchanan.co.uk>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/display/vga-helpers.h | 202 ++++++++++++++++++++++++++---------------------
>  hw/display/vga_int.h     |   1 +
>  hw/display/vga.c         |   5 +-
>  3 files changed, 114 insertions(+), 94 deletions(-)
-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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