[PATCH v2 0/5] HID: wacom: guard against NULL input devices on successful probe

[Jinmo Yang <jinmo44.yang@gmail.com>]

When wacom_setup_{pen,touch,pad}_input_capabilities() returns -ENODEV,
the corresponding input pointer is set to NULL but probe still succeeds.
Subsequent irq handlers dereference those pointers unconditionally,
causing NULL-pointer dereferences reachable from a spoofed HID device.

This series adds per-function NULL guards across all affected handlers.

Changes in v2:
  - Restructured per Jason Gerecke's review: replaced per-branch checks
    with per-function checks for dtus_irq, graphire_irq, and the Bamboo
    handlers — simpler and matches what each function actually requires.
  - wacom_intuos_pad() now returns 1 (not 0) when pad_input is NULL, so
    the report is consumed and does not fall through to
    wacom_intuos_inout() which would misparse a pad packet as a pen
    event (sashiko-bot).
  - wacom_intuos_bt_irq() now guards both pen_input and pad_input, since
    INTUOS4WL always has both on a single interface.
  - Added dev_warn_once at every guard (Jason).
  - Dropped the cp2112 patch (Benjamin prefers Dmitry's series).

Tested with uhid across 27 Wacom device types (spoofed bus):
                   unpatched  patched
  KASAN crashes          17        0
  probe failures          0        0
  hidraw nodes           26       26
  input registrations    25       25

Jinmo Yang (5):
  HID: wacom: check the input device in the shared report helpers
  HID: wacom: check the input devices in the legacy irq handlers
  HID: wacom: add NULL pad_input guard to wacom_intuos_pad()
  HID: wacom: add NULL input guards to wacom_intuos_bt_irq()
  HID: wacom: add NULL input guards to Bamboo touch/button handlers

 drivers/hid/wacom_wac.c | 90 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 87 insertions(+), 3 deletions(-)

-- 
2.53.0