[PATCH v3 0/5] platform/chrome: Fix a possible UAF via revocable

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

This is a follow-up series of [1].  It tries to fix a possible UAF in the
fops of cros_ec_chardev after the underlying protocol device has gone by
using revocable.

The 1st patch introduces the revocable which is an implementation of ideas
from the talk [2].

The 2nd and 3rd patches add test cases for revocable in Kunit and selftest.

The 4th patch converts existing protocol devices to resource providers
of cros_ec_device.

The 5th patch converts cros_ec_chardev to a resource consumer of
cros_ec_device to fix the UAF.

[1] https://lore.kernel.org/chrome-platform/20250721044456.2736300-6-tzungbi@kernel.org/
[2] https://lpc.events/event/17/contributions/1627/

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>

v3:
- Rebase onto https://lore.kernel.org/chrome-platform/20250828083601.856083-1-tzungbi@kernel.org
  and next-20250912.
- Change the 4th patch accordingly.

v2: https://lore.kernel.org/chrome-platform/20250820081645.847919-1-tzungbi@kernel.org
- Rename "ref_proxy" -> "revocable".
- Add test cases in Kunit and selftest.

v1: https://lore.kernel.org/chrome-platform/20250814091020.1302888-1-tzungbi@kernel.org/

Tzung-Bi Shih (5):
  revocable: Revocable resource management
  revocable: Add Kunit test cases
  selftests: revocable: Add kselftest cases
  platform/chrome: Protect cros_ec_device lifecycle with revocable
  platform/chrome: cros_ec_chardev: Consume cros_ec_device via revocable

 .../driver-api/driver-model/index.rst         |   1 +
 .../driver-api/driver-model/revocable.rst     | 151 ++++++++++++
 MAINTAINERS                                   |   9 +
 drivers/base/Kconfig                          |   8 +
 drivers/base/Makefile                         |   5 +-
 drivers/base/revocable.c                      | 229 ++++++++++++++++++
 drivers/base/revocable_test.c                 | 110 +++++++++
 drivers/platform/chrome/cros_ec.c             |   5 +
 drivers/platform/chrome/cros_ec_chardev.c     | 124 +++++++---
 include/linux/platform_data/cros_ec_proto.h   |   4 +
 include/linux/revocable.h                     |  37 +++
 tools/testing/selftests/Makefile              |   1 +
 .../selftests/drivers/base/revocable/Makefile |   7 +
 .../drivers/base/revocable/revocable_test.c   | 116 +++++++++
 .../drivers/base/revocable/test-revocable.sh  |  39 +++
 .../base/revocable/test_modules/Makefile      |  10 +
 .../revocable/test_modules/revocable_test.c   | 188 ++++++++++++++
 17 files changed, 1003 insertions(+), 41 deletions(-)
 create mode 100644 Documentation/driver-api/driver-model/revocable.rst
 create mode 100644 drivers/base/revocable.c
 create mode 100644 drivers/base/revocable_test.c
 create mode 100644 include/linux/revocable.h
 create mode 100644 tools/testing/selftests/drivers/base/revocable/Makefile
 create mode 100644 tools/testing/selftests/drivers/base/revocable/revocable_test.c
 create mode 100755 tools/testing/selftests/drivers/base/revocable/test-revocable.sh
 create mode 100644 tools/testing/selftests/drivers/base/revocable/test_modules/Makefile
 create mode 100644 tools/testing/selftests/drivers/base/revocable/test_modules/revocable_test.c

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