[Qemu-devel] [PULL 0/1] Vga 20180312 patches

[Qemu-devel] [PULL 0/1] Vga 20180312 patches

[Gerd Hoffmann]

The following changes since commit e4ae62b802cec437f877f2cadc4ef059cc0eca76:

  Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging (2018-03-09 17:28:16 +0000)

are available in the git repository at:

  git://git.kraxel.org/qemu tags/vga-20180312-pull-request

for you to fetch changes up to 7cdc61becd095b64a786b2625f321624e7111f3d:

  vga: fix region calculation (2018-03-12 11:45:21 +0100)

----------------------------------------------------------------
7cdc61becd vga: fix region calculation

----------------------------------------------------------------

Gerd Hoffmann (1):
  vga: fix region calculation

 hw/display/vga.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
2.9.3

[Qemu-devel] [PULL 1/1] vga: fix region calculation

[Gerd Hoffmann]

Typically the scanline length and the line offset are identical.  But
in case they are not our calculation for region_end is incorrect.  Using
line_offset is fine for all scanlines, except the last one where we have
to use the actual scanline length.

Fixes: CVE-2018-7550
Reported-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Prasad J Pandit <pjp@fedoraproject.org>
Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Message-id: 20180309143704.13420-1-kraxel@redhat.com
---
 hw/display/vga.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/display/vga.c b/hw/display/vga.c
index 28f298b342..72181330b8 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -1483,6 +1483,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
 
     region_start = (s->start_addr * 4);
     region_end = region_start + (ram_addr_t)s->line_offset * height;
+    region_end += width * s->get_bpp(s) / 8; /* scanline length */
+    region_end -= s->line_offset;
     if (region_end > s->vbe_size) {
         /* wraps around (can happen with cirrus vbe modes) */
         region_start = 0;
-- 
2.9.3

Re: [Qemu-devel] [PULL 0/1] Vga 20180312 patches

[Peter Maydell]

On 12 March 2018 at 10:59, Gerd Hoffmann <kraxel@redhat.com> wrote:
> The following changes since commit e4ae62b802cec437f877f2cadc4ef059cc0eca76:
>
>   Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging (2018-03-09 17:28:16 +0000)
>
> are available in the git repository at:
>
>   git://git.kraxel.org/qemu tags/vga-20180312-pull-request
>
> for you to fetch changes up to 7cdc61becd095b64a786b2625f321624e7111f3d:
>
>   vga: fix region calculation (2018-03-12 11:45:21 +0100)
>
> ----------------------------------------------------------------
> 7cdc61becd vga: fix region calculation
>
> ----------------------------------------------------------------
>
> Gerd Hoffmann (1):
>   vga: fix region calculation
>
>  hw/display/vga.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> --

Applied, thanks.

-- PMM

Re: [Qemu-devel] [PULL 1/1] vga: fix region calculation

[Mark Kanda]

On 3/12/2018 5:59 AM, Gerd Hoffmann wrote:
> Typically the scanline length and the line offset are identical.  But
> in case they are not our calculation for region_end is incorrect.  Using
> line_offset is fine for all scanlines, except the last one where we have
> to use the actual scanline length.
> 
> Fixes: CVE-2018-7550

This doesn't appear to be the correct CVE number.

https://nvd.nist.gov/vuln/detail/CVE-2018-7550

..please confirm..

Thanks,

-Mark

> Reported-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> Reviewed-by: Prasad J Pandit <pjp@fedoraproject.org>
> Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> Message-id: 20180309143704.13420-1-kraxel@redhat.com
> ---
>   hw/display/vga.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/hw/display/vga.c b/hw/display/vga.c
> index 28f298b342..72181330b8 100644
> --- a/hw/display/vga.c
> +++ b/hw/display/vga.c
> @@ -1483,6 +1483,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
>   
>       region_start = (s->start_addr * 4);
>       region_end = region_start + (ram_addr_t)s->line_offset * height;
> +    region_end += width * s->get_bpp(s) / 8; /* scanline length */
> +    region_end -= s->line_offset;
>       if (region_end > s->vbe_size) {
>           /* wraps around (can happen with cirrus vbe modes) */
>           region_start = 0;
>