[PATCH v6 0/3] platform/chrome: Fix an UAF via replacing fops

[Tzung-Bi Shih <tzungbi@kernel.org>]

The series is separated from [1] to show the independency and compare
potential use cases easier.  This use case replaces filp->f_op to
revocable-aware warppers.  It relies on the revocable core part [2].

It tries to fix an UAF in the fops of cros_ec_chardev after the
underlying protocol device has gone by using revocable.

The warppers make sure file operations in drivers won't be called if the
resource has been revoked.

The 1st patch introduces revocable fops replacement.

The 2nd patch supports the fops replacement in miscdevice.

The 3rd patch uses the support from miscdevice to fix the UAF.

[1] https://lore.kernel.org/chrome-platform/20251016054204.1523139-1-tzungbi@kernel.org
[2] https://lore.kernel.org/chrome-platform/20251106152330.11733-1-tzungbi@kernel.org/

v6:
- New, separated from an existing series.

Tzung-Bi Shih (3):
  revocable: Add fops replacement
  char: misc: Leverage revocable fops replacement
  platform/chrome: cros_ec_chardev: Secure cros_ec_device via revocable

 drivers/char/misc.c                       |  18 ++-
 drivers/platform/chrome/cros_ec_chardev.c |   1 +
 fs/Makefile                               |   2 +-
 fs/fs_revocable.c                         | 156 ++++++++++++++++++++++
 include/linux/fs_revocable.h              |  14 ++
 include/linux/miscdevice.h                |   2 +
 6 files changed, 190 insertions(+), 3 deletions(-)
 create mode 100644 fs/fs_revocable.c
 create mode 100644 include/linux/fs_revocable.h

-- 
2.48.1