HID: intel-ish-hid: fix NULL-ptr-deref in ishtp_bus_remove_all_clients

Overview

In the Linux kernel, the following vulnerability has been resolved:

HID: intel-ish-hid: fix NULL-ptr-deref in ishtp_bus_remove_all_clients

During a warm reset flow, the cl->device pointer may be NULL if the reset occurs while clients are still being enumerated. Accessing cl->device->reference_count without a NULL check leads to a kernel panic.

This issue was identified during multi-unit warm reboot stress clycles. Add a defensive NULL check for cl->device to ensure stability under such intensive testing conditions.

KASAN: null-ptr-deref in range [0000000000000000-0000000000000007] Workqueue: ish_fw_update_wq fw_reset_work_fn

Call Trace: ishtp_bus_remove_all_clients+0xbe/0x130 [intel_ishtp] ishtp_reset_handler+0x85/0x1a0 [intel_ishtp] fw_reset_work_fn+0x8a/0xc0 [intel_ish_ipc]

Affected

• Linux >= 3703f53b99e4a7c373ce3568dd3f91f175ebb626 < cde7f709d1025dadfc52e903e43981c1644bd8bd
• Linux >= 3703f53b99e4a7c373ce3568dd3f91f175ebb626 < 0b605e8ce60698c27a26f512968a597fd620d2e8
• Linux >= 3703f53b99e4a7c373ce3568dd3f91f175ebb626 < feb4bcfd405282de60aba321f13a1272b30c5af4
• Linux >= 3703f53b99e4a7c373ce3568dd3f91f175ebb626 < 272dac57caa981718e7188c80c703e7bb1998054
• Linux >= 3703f53b99e4a7c373ce3568dd3f91f175ebb626 < 56f7db581ee73af53cd512e00a6261a025bf1d58
• Linux 4.9

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.