netrom: hold sock when setting skb->destructor

[ Upstream commit 4638faac032756f7eab5524be7be56bee77e426b ]

sock_efree() releases the sock refcnt, if we don't hold this refcnt
when setting skb->destructor to it, the refcnt would not be balanced.
This leads to several bug reports from syzbot.

I have checked other users of sock_efree(), all of them hold the
sock refcnt.

Fixes: c8c8218ec5af ("netrom: fix a memory leak in nr_rx_frame()")
Reported-and-tested-by: <syzbot+622bdabb128acc33427d@syzkaller.appspotmail.com>
Reported-and-tested-by: <syzbot+6eaef7158b19e3fec3a0@syzkaller.appspotmail.com>
Reported-and-tested-by: <syzbot+9399c158fcc09b21d0d2@syzkaller.appspotmail.com>
Reported-and-tested-by: <syzbot+a34e5f3d0300163f0c87@syzkaller.appspotmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Cong Wang 2019-07-22 20:41:22 -07:00 committed by prashantpaddune
parent 3b3cb135ff
commit e0dd03cdcc

View File

@ -968,6 +968,7 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
window = skb->data[20]; window = skb->data[20];
sock_hold(make);
skb->sk = make; skb->sk = make;
skb->destructor = sock_efree; skb->destructor = sock_efree;
make->sk_state = TCP_ESTABLISHED; make->sk_state = TCP_ESTABLISHED;