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From: Blue Swirl <blauwirbel@gmail.com>
Date: Sun, 3 Oct 2010 07:52:00 +0000
Message-ID: <AANLkTimM2SQc1gy2aY9rJjDe9kHc5eajGZFyZFnapNAo@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH] console: Avoid dereferencing NULL
	active_console
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To: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, Michal Suchanek <hramrach@centrum.cz>, Gerd Hoffmann <kraxel@redhat.com>

Thanks, applied.

On Mon, Sep 20, 2010 at 1:11 PM, Stefan Hajnoczi
<stefanha@linux.vnet.ibm.com> wrote:
> The console_select() function does not check that active_console is
> non-NULL before dereferencing it. =C2=A0When invoked with qemu -nodefault=
s it
> is possible to hit this case.
>
> This patch checks that active_console is non-NULL before stashing away
> the old console dimensions in console_select().
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
> =C2=A0console.c | =C2=A0 =C2=A06 ++++--
> =C2=A01 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/console.c b/console.c
> index 698bc10..c1728b1 100644
> --- a/console.c
> +++ b/console.c
> @@ -1060,8 +1060,10 @@ void console_select(unsigned int index)
>
> =C2=A0 =C2=A0 if (index >=3D MAX_CONSOLES)
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 return;
> - =C2=A0 =C2=A0active_console->g_width =3D ds_get_width(active_console->d=
s);
> - =C2=A0 =C2=A0active_console->g_height =3D ds_get_height(active_console-=
>ds);
> + =C2=A0 =C2=A0if (active_console) {
> + =C2=A0 =C2=A0 =C2=A0 =C2=A0active_console->g_width =3D ds_get_width(act=
ive_console->ds);
> + =C2=A0 =C2=A0 =C2=A0 =C2=A0active_console->g_height =3D ds_get_height(a=
ctive_console->ds);
> + =C2=A0 =C2=A0}
> =C2=A0 =C2=A0 s =3D consoles[index];
> =C2=A0 =C2=A0 if (s) {
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 DisplayState *ds =3D s->ds;
> --
> 1.7.1
>
>
>