Map qxl rom read-only into the guest, so the guest can't tamper with the
content. qxl has a shadow copy of the rom to deal with that, but the
shadow doesn't cover the mode list. A privilidged user in the guest can
manipulate the mode list and that to trick qemu into oob reads, leading
to a DoS via segfault if that read access happens to hit unmapped memory.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200225055920.17261-2-kraxel@redhat.com
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