[PATCH 0/4] HID: Proper fix for OOM in hid-core

Benjamin Tissoires
2026-04-15T09:38:49Z

Commit 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing
bogus memset()") enforced the provided data to be at least the size of
the declared buffer in the report descriptor to prevent a buffer
overflow.

We only had corner cases of malicious devices exposing the OOM because
in most cases, the buffer provided by the transport layer needs to be
allocated at probe time and is large enough to handle all the possible
reports.

However, the patch from above, which enforces the spec a little bit more
introduced both regressions for devices not following the spec (not
necesserally malicious), but also a stream of errors for those devices.

Let's revert to the old behavior by giving more information to HID core
to be able to decide whether it can or not memset the rest of the buffer
to 0 and continue the processing.

Note that the first commit makes an API change, but the callers are
relatively limited, so it should be fine on its own. The second patch
can't really make the same kind of API change because we have too many
callers in various subsystems. We can switch them one by one to the safe
approach when needed.

The last 2 patches are small cleanups I initially put together with the
2 first patches, but they can be applied on their own and don't need to
be pulled in stable like the first 2.

Cheers,
Benjamin

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
Benjamin Tissoires (4):
HID: pass the buffer size to hid_report_raw_event
HID: core: introduce hid_safe_input_report()
HID: multitouch: use __free(kfree) to clean up temporary buffers
HID: wacom: use __free(kfree) to clean up temporary buffers

drivers/hid/bpf/hid_bpf_dispatch.c | 6 ++--
drivers/hid/hid-core.c | 63 +++++++++++++++++++++++++++++---------
drivers/hid/hid-gfrm.c | 4 +--
drivers/hid/hid-logitech-hidpp.c | 2 +-
drivers/hid/hid-multitouch.c | 18 +++++------
drivers/hid/hid-primax.c | 2 +-
drivers/hid/hid-vivaldi-common.c | 2 +-
drivers/hid/i2c-hid/i2c-hid-core.c | 7 +++--
drivers/hid/usbhid/hid-core.c | 11 ++++---
drivers/hid/wacom_sys.c | 46 ++++++++++------------------
drivers/staging/greybus/hid.c | 2 +-
include/linux/hid.h | 6 ++--
include/linux/hid_bpf.h | 14 ++++++---
13 files changed, 105 insertions(+), 78 deletions(-)
---
base-commit: 7df6572f1cb381d6b89ceed58e3b076c233c2cd0
change-id: 20260415-wip-fix-core-7d85c8516ed0

Best regards,
--
Benjamin Tissoires <bentiss@kernel.org>