Re: [RFC PATCH-for-7.2 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt()

[Stefan Hajnoczi]

On Mon, 28 Nov 2022 at 08:50, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
>
> Since v1:
> - Addressed Marc-André review comments
> - Moved overrun check in qxl_get_check_slot_offset()
>
> memory_region_get_ram_ptr() returns a host pointer for a
> MemoryRegion. Sometimes we do offset calculation using this
> pointer without checking the underlying MemoryRegion size.
>
> Wenxu Yin reported a buffer overrun in QXL. This series
> aims to fix it. I haven't audited the other _get_ram_ptr()
> uses (yet). Eventually we could rename it _get_ram_ptr_unsafe
> and add a safer helper which checks for overrun.
>
> Worth considering for 7.2?

Yes, please. If Gerd is happy I'll merge it.

Stefan

>
> Regards,
>
> Phil.
>
> Philippe Mathieu-Daudé (5):
>   hw/display/qxl: Have qxl_log_command Return early if no log_cmd
>     handler
>   hw/display/qxl: Document qxl_phys2virt()
>   hw/display/qxl: Pass requested buffer size to qxl_phys2virt()
>   hw/display/qxl: Avoid buffer overrun in qxl_phys2virt (CVE-2022-4144)
>   hw/display/qxl: Assert memory slot fits in preallocated MemoryRegion
>
>  hw/display/qxl-logger.c | 22 +++++++++++++++++++---
>  hw/display/qxl-render.c | 12 ++++++++----
>  hw/display/qxl.c        | 37 ++++++++++++++++++++++++++++---------
>  hw/display/qxl.h        | 23 ++++++++++++++++++++++-
>  4 files changed, 77 insertions(+), 17 deletions(-)
>
> --
> 2.38.1
>
>