[v3,0/5] Introduce new wrappers to copy user-arrays

Message

Philipp Stanner Sept. 20, 2023, 12:36 p.m. UTC

Hi!

David Airlie suggested that we could implement new wrappers around
(v)memdup_user() for duplicating user arrays.

This small patch series first implements the two new wrapper functions
memdup_array_user() and vmemdup_array_user(). They calculate the
array-sizes safely, i.e., they return an error in case of an overflow.

It then implements the new wrappers in two components in kernel/ and two
in the drm-subsystem.

In total, there are 18 files in the kernel that use (v)memdup_user() to
duplicate arrays. My plan is to provide patches for the other 14
successively once this series has been merged.


Changes since v2:
- Remove the unlikely() from the overflow-check, since the latter
  already implements one (Dan Carpenter)
- Add the Reviewd-bys for the changes already reviewed in v2

Changes since v1:
- Insert new headers alphabetically ordered
- Remove empty lines in functions' docstrings
- Return -EOVERFLOW instead of -EINVAL from wrapper functions

P.

Philipp Stanner (5):
  string.h: add array-wrappers for (v)memdup_user()
  kernel: kexec: copy user-array safely
  kernel: watch_queue: copy user-array safely
  drm_lease.c: copy user-array safely
  drm: vmgfx_surface.c: copy user-array safely

 drivers/gpu/drm/drm_lease.c             |  4 +--
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |  4 +--
 include/linux/string.h                  | 40 +++++++++++++++++++++++++
 kernel/kexec.c                          |  2 +-
 kernel/watch_queue.c                    |  2 +-
 5 files changed, 46 insertions(+), 6 deletions(-)