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Re: [PATCH v2 1/2] ait-vga: check address before reading configuration b
From: |
Daniel P . Berrangé |
Subject: |
Re: [PATCH v2 1/2] ait-vga: check address before reading configuration bytes |
Date: |
Thu, 4 Jun 2020 09:43:18 +0100 |
User-agent: |
Mutt/1.13.4 (2020-02-15) |
Typo: s/ait/ati/
On Thu, Jun 04, 2020 at 01:52:50AM +0530, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> While reading PCI configuration bytes, a guest may send an
> address towards the end of the configuration space. It may lead
> to an OOB access issue. Add check to ensure 'address + size' is
> within PCI configuration space.
Please include a CVE number for this security flaw if there is
one.
>
> Reported-by: Ren Ding <rding@gatech.edu>
> Reported-by: Hanqing Zhao <hanqing@gatech.edu>
> Reported-by: Yi Ren <c4tren@gmail.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
> hw/display/ati.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> Update v2: add check to avoid OOB PCI configuration space access
> -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00711.html
>
> diff --git a/hw/display/ati.c b/hw/display/ati.c
> index bda4a2d816..6671959e5d 100644
> --- a/hw/display/ati.c
> +++ b/hw/display/ati.c
> @@ -384,7 +384,10 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr,
> unsigned int size)
> val = s->regs.crtc_pitch;
> break;
> case 0xf00 ... 0xfff:
> - val = pci_default_read_config(&s->dev, addr - 0xf00, size);
> + addr = addr - 0xf00;
> + if (addr + size <= 0xff) {
> + val = pci_default_read_config(&s->dev, addr, size);
> + }
> break;
> case CUR_OFFSET:
> val = s->regs.cur_offset;
> --
> 2.26.2
>
Regards,
Daniel
--
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- [PATCH v2 0/2] Ensure PCI configuration access is within bounds, P J P, 2020/06/03
- [PATCH v2 2/2] pci: ensure configuration access is within bounds, P J P, 2020/06/03
- Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds, BALATON Zoltan, 2020/06/03
- Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds, P J P, 2020/06/04
- Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds, Philippe Mathieu-Daudé, 2020/06/04
- Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds, Michael S. Tsirkin, 2020/06/04
- Re: [PATCH v2 2/2] pci: ensure configuration access is within bounds, BALATON Zoltan, 2020/06/04