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authorCong Wang <xiyou.wangcong@gmail.com>2020-05-01 11:11:08 -0700
committerDavid S. Miller <davem@davemloft.net>2020-05-04 11:59:20 -0700
commit93a2014afbace907178afc3c9c1e62c9a338595a (patch)
tree4d072dccbc4a89676c4c0b16a27162c9a4cdbe79
parent44d95cc6b10ff7439d45839c96c581cb4368c088 (diff)
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: Gengming Liu <l.dmxcsnsbh@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/atm/common.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/net/atm/common.c b/net/atm/common.c
index 0ce530af534d..8575f5d52087 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -177,18 +177,18 @@ 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)
- vcc->dev->ops->close(vcc);
- if (vcc->push)
- vcc->push(vcc, NULL); /* atmarpd has no push */
- module_put(vcc->owner);
-
- while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
- atm_return(vcc, skb->truesize);
- kfree_skb(skb);
- }
+ if (vcc->dev && vcc->dev->ops->close)
+ vcc->dev->ops->close(vcc);
+ if (vcc->push)
+ vcc->push(vcc, NULL); /* atmarpd has no push */
+ module_put(vcc->owner);
+
+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+ atm_return(vcc, skb->truesize);
+ kfree_skb(skb);
+ }
+ if (vcc->dev && vcc->dev->ops->owner) {
module_put(vcc->dev->ops->owner);
atm_dev_put(vcc->dev);
}