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Date: Sun, 29 Jun 2014 10:12:13 -0700
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From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] possible denial of service via VNC
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To: Peter Lieven <pl@kamp.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

On Sun, Jun 29, 2014 at 5:16 AM, Peter Lieven <pl@kamp.de> wrote:
> Hi,
>
> while debugging a VNC issue I found this:
>
>     case VNC_MSG_CLIENT_CUT_TEXT:
>         if (len == 1)
>             return 8;
>
>         if (len == 8) {
>             uint32_t dlen = read_u32(data, 4);
>             if (dlen > 0)
>                 return 8 + dlen;
>         }
>
>         client_cut_text(vs, read_u32(data, 4), data + 8);
>         break;
>
> in protocol_client_msg().
>
> Is this really a good idea? This allows for letting the vs->input buffer to grow
> up to 2^32 + 8 byte which will possibly result in an out of memory condition.

The spec allows cut operations of this size.  What would a reasonable limit be?

Regards,

Anthony Liguori

> PeterY
>
>