Bug 2395797 (CVE-2025-39818)

Summary: CVE-2025-39818 kernel: HID: intel-thc-hid: intel-thc: Fix incorrect pointer arithmetic in I2C regs save
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-09-16 14:03:17 UTC 
In the Linux kernel, the following vulnerability has been resolved:

HID: intel-thc-hid: intel-thc: Fix incorrect pointer arithmetic in I2C regs save

Improper use of secondary pointer (&dev->i2c_subip_regs) caused
kernel crash and out-of-bounds error:

 BUG: KASAN: slab-out-of-bounds in _regmap_bulk_read+0x449/0x510
 Write of size 4 at addr ffff888136005dc0 by task kworker/u33:5/5107

 CPU: 3 UID: 0 PID: 5107 Comm: kworker/u33:5 Not tainted 6.16.0+ #3 PREEMPT(voluntary)
 Workqueue: async async_run_entry_fn
 Call Trace:
  <TASK>
  dump_stack_lvl+0x76/0xa0
  print_report+0xd1/0x660
  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
  ? kasan_complete_mode_report_info+0x26/0x200
  kasan_report+0xe1/0x120
  ? _regmap_bulk_read+0x449/0x510
  ? _regmap_bulk_read+0x449/0x510
  __asan_report_store4_noabort+0x17/0x30
  _regmap_bulk_read+0x449/0x510
  ? __pfx__regmap_bulk_read+0x10/0x10
  regmap_bulk_read+0x270/0x3d0
  pio_complete+0x1ee/0x2c0 [intel_thc]
  ? __pfx_pio_complete+0x10/0x10 [intel_thc]
  ? __pfx_pio_wait+0x10/0x10 [intel_thc]
  ? regmap_update_bits_base+0x13b/0x1f0
  thc_i2c_subip_pio_read+0x117/0x270 [intel_thc]
  thc_i2c_subip_regs_save+0xc2/0x140 [intel_thc]
  ? __pfx_thc_i2c_subip_regs_save+0x10/0x10 [intel_thc]
[...]
 The buggy address belongs to the object at ffff888136005d00
  which belongs to the cache kmalloc-rnd-12-192 of size 192
 The buggy address is located 0 bytes to the right of
  allocated 192-byte region [ffff888136005d00, ffff888136005dc0)

Replaced with direct array indexing (&dev->i2c_subip_regs[i]) to ensure
safe memory access.
Comment 1 Keith Grant 2025-09-16 16:08:59 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025091615-CVE-2025-39818-f1b9@gregkh/T