From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: "zhangxiaoxu (A)" <zhangxiaoxu5@huawei.com>
Cc: akpm@osdl.org, pmladek@suse.com, wangkefeng.wang@huawei.com,
b.zolnierkie@samsung.com, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org, sergey.senozhatsky@gmail.com
Subject: Re: [PATCH] vgacon: Fix a UAF in vgacon_invert_region
Date: Tue, 03 Mar 2020 14:46:49 +0000 [thread overview]
Message-ID: <20200303144649.GT13686@intel.com> (raw)
In-Reply-To: <67073029-8477-5f5a-ed2a-bb5ad4896878@huawei.com>
On Tue, Mar 03, 2020 at 10:30:14PM +0800, zhangxiaoxu (A) wrote:
>
>
> 在 2020/3/3 21:59, Ville Syrjälä 写道:
> > That doesn't match how vc_screenbuf_size is computed elsewhere. Also
> > a lot of places seem to assume that the screenbuf can be larger than
> > vga_vram_size (eg. all the memcpy()s pick the smaller size of the
> > two).
> Yes, in the vga source code, we also pick the smaller size of two. But
> in other place, eg: vc_do_resize, copy the old_origin to new_origin, we
> not do that. It also make bad access happen. it maybe CVE-2020-8647.
>
> I think we should just assume the width/height maybe larger than the
> default, not the screenbuf larger than vga_vram_size.
>
> If not, any useful of the larger screenbuf?
Maybe used for scrolling?
>
> >
> > And you're changing the behaviour of the code when
> > 'width % 2 && user' is true
--
Ville Syrjälä
Intel
next prev parent reply other threads:[~2020-03-03 14:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 3:20 [PATCH] vgacon: Fix a UAF in vgacon_invert_region Zhang Xiaoxu
2020-03-03 13:59 ` Ville Syrjälä
2020-03-03 14:30 ` zhangxiaoxu (A)
2020-03-03 14:46 ` Ville Syrjälä [this message]
2020-03-04 1:31 ` zhangxiaoxu (A)
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