usb: gadget: u_ether: Fix race between gether_disconnect and… (CVE-2026-31728)

Résumé

usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop

Description d'origine

La description telle que publiée par la source (souvent en anglais).

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

usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop

A race condition between gether_disconnect() and eth_stop() leads to a
NULL pointer dereference. Specifically, if eth_stop() is triggered
concurrently while gether_disconnect() is tearing down the endpoints,
eth_stop() attempts to access the cleared endpoint descriptor, causing
the following NPE:

Unable to handle kernel NULL pointer dereference
Call trace:
__dwc3_gadget_ep_enable+0x60/0x788
dwc3_gadget_ep_enable+0x70/0xe4
usb_ep_enable+0x60/0x15c
eth_stop+0xb8/0x108

Because eth_stop() crashes while holding the dev->lock, the thread
running gether_disconnect() fails to acquire the same lock and spins
forever, resulting in a hardlockup:

Core - Debugging Information for Hardlockup core(7)
Call trace:
queued_spin_lock_slowpath+0x94/0x488
_raw_spin_lock+0x64/0x6c
gether_disconnect+0x19c/0x1e8
ncm_set_alt+0x68/0x1a0
composite_setup+0x6a0/0xc50

The root cause is that the clearing of dev->port_usb in
gether_disconnect() is delayed until the end of the function.

Move the clearing of dev->port_usb to the very beginning of
gether_disconnect() while holding dev->lock. This cuts off the link
immediately, ensuring eth_stop() will see dev->port_usb as NULL and
safely bail out.

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Paquets affectés

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.27"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.169"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}]

État des correctifs par distribution

Paquets corrigés publiés par chaque distribution pour cette CVE

BellSoft Alpaquita BELL-CVE-2026-31728 linux-lts Corrigé dans: 6.1.170-r0
Debian DEBIAN-CVE-2026-31728 linux Corrigé dans: 5.10.257-1
Ubuntu UBUNTU-CVE-2026-31728 linux

Résumé

Description d'origine

Paquets affectés

État des correctifs par distribution

Références