Commit 93a2014a authored by Cong Wang's avatar Cong Wang Committed by David S. Miller

atm: fix a UAF in lec_arp_clear_vccs()

Gengming reported a UAF in lec_arp_clear_vccs(),
where we add a vcc socket to an entry in a per-device
list but free the socket without removing it from the
list when vcc->dev is NULL.

We need to call lec_vcc_close() to search and remove
those entries contain the vcc being destroyed. This can
be done by calling vcc->push(vcc, NULL) unconditionally
in vcc_destroy_socket().

Another issue discovered by Gengming's reproducer is
the vcc->dev may point to the static device lecatm_dev,
for which we don't need to register/unregister device,
so we can just check for vcc->dev->ops->owner.
Reported-by: default avatarGengming Liu <l.dmxcsnsbh@gmail.com>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 44d95cc6
......@@ -177,8 +177,7 @@ static void vcc_destroy_socket(struct sock *sk)
set_bit(ATM_VF_CLOSE, &vcc->flags);
clear_bit(ATM_VF_READY, &vcc->flags);
if (vcc->dev) {
if (vcc->dev->ops->close)
if (vcc->dev && vcc->dev->ops->close)
vcc->dev->ops->close(vcc);
if (vcc->push)
vcc->push(vcc, NULL); /* atmarpd has no push */
......@@ -189,6 +188,7 @@ static void vcc_destroy_socket(struct sock *sk)
kfree_skb(skb);
}
if (vcc->dev && vcc->dev->ops->owner) {
module_put(vcc->dev->ops->owner);
atm_dev_put(vcc->dev);
}
......
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