[RFC PATCH-for-7.2 v3 0/5] hw/display/qxl: Avoid buffer overrun in qxl_phys2virt()

[Philippe Mathieu-Daudé]

Since v2:
- Do not abort checking guest-provided addresses (Stefan)
- Handle chunked QEMUCursor (Gerd)

Since v1:
- Moved overrun check in qxl_get_check_slot_offset (Marc-André)

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?

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 | 20 ++++++++++++++++----
 hw/display/qxl.c        | 42 ++++++++++++++++++++++++++++++++---------
 hw/display/qxl.h        | 23 +++++++++++++++++++++-
 4 files changed, 90 insertions(+), 17 deletions(-)

-- 
2.38.1