From: Gerd Hoffmann <kraxel@redhat.com>
To: Laszlo Ersek <lersek@redhat.com>
Cc: Li Qiang <liq3ea@gmail.com>,
qemu-devel@nongnu.org, ghoffman@redhat.com, liqiang6-s@360.cn
Subject: Re: [Qemu-devel] [PATCH] cirrus: fix oob access issue
Date: Tue, 24 Jan 2017 11:48:50 +0100 [thread overview]
Message-ID: <1485254930.32716.23.camel@redhat.com> (raw)
In-Reply-To: <237b1da5-532d-afd6-84ad-6adc5bd97291@redhat.com>
> > diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
> > index 379910d..7ddd289 100644
> > --- a/hw/display/cirrus_vga.c
> > +++ b/hw/display/cirrus_vga.c
> > @@ -277,7 +277,8 @@ static bool blit_region_is_unsafe(struct CirrusVGAState *s,
> > }
> > if (pitch < 0) {
> > int64_t min = addr
> > - + ((int64_t)s->cirrus_blt_height-1) * pitch;
> > + + ((int64_t)s->cirrus_blt_height-1) * pitch
> > + - s->cirrus_blt_width;
> > int32_t max = addr
> > + s->cirrus_blt_width;
> > if (min < 0 || max > s->vga.vram_size) {
> >
>
> I believe this is incorrect. In this case (AFAIR), "addr" points to the
> left-most pixel (= lowest address) of the bottom line (= highest
> address).
If I read the code correctly it is backwards *both* x and y axis, so
addr is the right-most pixel of the bottom line.
cheers,
Gerd
next prev parent reply other threads:[~2017-01-24 10:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-24 9:34 [Qemu-devel] [PATCH] cirrus: fix oob access issue Li Qiang
2017-01-24 9:50 ` no-reply
2017-01-24 10:23 ` Laszlo Ersek
2017-01-24 10:48 ` Gerd Hoffmann [this message]
2017-01-24 11:17 ` Laszlo Ersek
2017-01-24 11:24 ` Laszlo Ersek
2017-01-24 12:29 ` Gerd Hoffmann
2017-01-24 15:31 ` Wolfgang Bumiller
2017-01-24 16:12 ` Laszlo Ersek
2017-01-25 1:18 ` Li Qiang
2017-01-25 3:31 ` Laszlo Ersek
2017-01-25 7:26 ` Gerd Hoffmann
2017-01-25 7:18 ` Gerd Hoffmann
2017-01-25 10:13 ` Laszlo Ersek
2017-01-24 9:58 Li Qiang
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