Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix xmit_frame/xmit_buf leaks on mgnt-frame error paths issue_beacon(), issue_probersp() and issue_asocrsp() obtain a management xmit_frame together with its xmit_buf from the driver's fixed-size management-TX pools via alloc_mgtxmitframe(). On the normal path the frame is handed to dump_mgntframe(), which transfers ownership and eventually returns both objects to their pools (the frame and, for beacons, the buf in rtl8723bs_mgnt_xmit(); other bufs via the pending-xmitbuf/TX-completion path). Several error/edge paths return early after a successful alloc_mgtxmitframe() but before dump_mgntframe(), so ownership is never transferred and neither object is freed: - issue_beacon(): beacon larger than 512 bytes - issue_probersp(): cur_network->ie_length > MAX_IE_SZ - issue_probersp(): kzalloc() of the SSID scratch buffer fails - issue_asocrsp(): pkt_type is neither ASSOCRSP nor REASSOCRSP Because alloc_mgtxmitframe() removes the frame and buf from their free lists (list_del_init) without placing them on any pending list, an orphaned pair is on no list and referenced by nobody, so it is only reclaimed at driver teardown. Repeated hits progressively exhaust the management-TX pools until alloc_mgtxmitframe() returns NULL and the interface can no longer send beacons or probe/assoc responses. Free the frame and buffer on these paths, matching the existing correct error handling in issue_assocreq().

Affected versions

Linux: 554c0a3abf216c991c5ebddcdb2c08689ecd290b through before 6c9f6a3b9fdd31a0836b681053155b5997c0156e (git); 554c0a3abf216c991c5ebddcdb2c08689ecd290b through before c48e5aa01525577d6b6e782962a5bfb0e1535cb5 (git); 554c0a3abf216c991c5ebddcdb2c08689ecd290b through before 41b8209376dffbd7b0b85c8bc4697d9166ac62ef (git); 4.12 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.