netrom: hold sock when setting skb->destructor

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: c8c8218ec5 ("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>
This commit is contained in:
Cong Wang 2019-07-22 20:41:22 -07:00 committed by David S. Miller
parent 260637903f
commit 4638faac03
1 changed files with 1 additions and 0 deletions
net/netrom

View File

@ -967,6 +967,7 @@ 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;