Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: wifi: mwifiex: Detach sync cmd buffer on interrupted wait mwifiex synchronous commands keep the caller-provided data buffer in cmd_node->data_buf. Several callers pass stack-allocated objects there. If wait_event_interruptible_timeout() is interrupted, the caller can return and release that stack object while the firmware command is still the current command. A late firmware response then reaches the normal response handler, which can copy data through cmd_node->data_buf into the stale stack address. This fixes a stack corruption observed during repeated association and disassociation cycles. The panic trace showed the command wait being interrupted immediately before a bad pointer dereference: cmd_wait_q terminated: -512 Unable to handle kernel paging request at virtual address 002c583837384662 Kernel panic - not syncing: stack-protector: Kernel stack is corrupted ... Tainted: [M]=MACHINE_CHECK The fault address decodes as little-endian ASCII: 0x002c583837384662 -> "bF878X,\0" which is a fragment of the VERSION_EXT firmware string exposed as debugfs "verext": w8997o-V4, RF878X, FP92, 16.92.21.p153.7 The same runs also showed corrupted control data containing: 0x2400372e333531 -> "153.7\0$" which is the tail of the same VERSION_EXT string. This points at a late VERSION_EXT response writing through a stale stack-backed data_buf after the interrupted wait returned. After cancelling pending commands on an interrupted or timed-out wait, detach the caller-owned data buffer from the still-current command. This preserves the existing command cancellation behaviour while preventing a late response from writing through a pointer whose lifetime ended with the waiting caller. Tested on an i.MX8MP board using an 88W8997.

Affected versions

Linux: 3d026d09b28dda24777129a931634949c75a9181 through before 20ee9c03f261bf6ac59331e2ca7b46b23646412a (git); 3d026d09b28dda24777129a931634949c75a9181 through before b1bbeb8970eeb6c6bf3cd5314138103f7b69446d (git); 3d026d09b28dda24777129a931634949c75a9181 through before d29a165588b6a0cf7a38db5cbd602aef7ef8c658 (git); 3d026d09b28dda24777129a931634949c75a9181 through before ef06882c7d8a7400b67d0d003b1008093dd589ed (git); 3.15 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.