CVE-2021-47459 Information

Description

In the Linux kernel the following vulnerability has been resolved:

can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv

It will trigger UAF for rx_kref of j1939_priv as following.

    cpu0                                    cpu1

j1939_sk_bind(socket0 ndev0 …) j1939_netdev_start j1939_sk_bind(socket1 ndev0 …) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ….. j1939_netdev_stop kref_put_lock(&priv->rx_kref …) kref_get(&priv->rx_kref …) REFCOUNT_WARN(ddition on 0;…)

==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0

The rx_kref’s kref_get() and kref_put() should use j1939_netdev_lock to protect.

Reference

https://git.kernel.org/stable/c/a0e47d2833b4f65e6c799f28c6b636d36b8b936d https://git.kernel.org/stable/c/864e77771a24c877aaf53aee019f78619cbcd668 https://git.kernel.org/stable/c/6e8811707e2df0c6ba920f0cad3a3bca7b42132f https://git.kernel.org/stable/c/d9d52a3ebd284882f5562c88e55991add5d01586