Sanity checks are applied when the fifo is enabled by the guest
(SVGA_REG_CONFIG_DONE write). Which doesn't help much if the guest
changes the fifo registers afterwards. Move the checks to
vmsvga_fifo_length so they are done each time qemu is about to read
from the fifo.
Fixes: CVE-2016-4454
Cc: qemu-stable@nongnu.org
Cc: P J P <ppandit@redhat.com>
Reported-by: 李强 <liqiang6-s@360.cn>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1464592161-18348-2-git-send-email-kraxel@redhat.com
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