Re: [PATCH 1/2] qxl: map rom r/o

2020-02-25 Thread Philippe Mathieu-Daudé
On 2/25/20 6:59 AM, Gerd Hoffmann wrote: 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 tri

[PATCH 1/2] qxl: map rom r/o

2020-02-24 Thread Gerd Hoffmann
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 vi