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[LTS 9.2] can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv #487

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Merged
merged 1 commit into from
Aug 12, 2025
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[LTS 9.2] can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv #487

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7 changes: 5 additions & 2 deletions net/can/j1939/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -253,11 +253,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
struct j1939_priv *priv, *priv_new;
int ret;

priv = j1939_priv_get_by_ndev(ndev);
spin_lock(&j1939_netdev_lock);
priv = j1939_priv_get_by_ndev_locked(ndev);
if (priv) {
kref_get(&priv->rx_kref);
spin_unlock(&j1939_netdev_lock);
return priv;
}
spin_unlock(&j1939_netdev_lock);

priv = j1939_priv_create(ndev);
if (!priv)
Expand All @@ -273,10 +276,10 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
/* Someone was faster than us, use their priv and roll
* back our's.
*/
kref_get(&priv_new->rx_kref);
spin_unlock(&j1939_netdev_lock);
dev_put(ndev);
kfree(priv);
kref_get(&priv_new->rx_kref);
return priv_new;
}
j1939_priv_set(ndev, priv);
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