| Message ID | 1587618786-13481-1-git-send-email-xiyuyang19@fudan.edu.cn |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net/x25: Fix x25_neigh refcnt leak when reveiving frame | expand |
On 2020/4/23 13:13, Xiyu Yang wrote: > x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a > reference of the specified x25_neigh object to "nb" with increased > refcnt. > > When x25_lapb_receive_frame() returns, local variable "nb" becomes > invalid, so the refcount should be decreased to keep refcount balanced. > > The reference counting issue happens in one path of > x25_lapb_receive_frame(). When pskb_may_pull() returns false, the > function forgets to decrease the refcnt increased by x25_get_neigh(), > causing a refcnt leak. > > Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns > false. > Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs") > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> > --- > net/x25/x25_dev.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c > index 00e782335cb0..25bf72ee6cad 100644 > --- a/net/x25/x25_dev.c > +++ b/net/x25/x25_dev.c > @@ -115,8 +115,10 @@ int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, > goto drop; > } > > - if (!pskb_may_pull(skb, 1)) > + if (!pskb_may_pull(skb, 1)) { > + x25_neigh_put(nb); > return 0; > + } > > switch (skb->data[0]) { > >
From: Xiyu Yang <xiyuyang19@fudan.edu.cn> Date: Thu, 23 Apr 2020 13:13:03 +0800 > x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a > reference of the specified x25_neigh object to "nb" with increased > refcnt. > > When x25_lapb_receive_frame() returns, local variable "nb" becomes > invalid, so the refcount should be decreased to keep refcount balanced. > > The reference counting issue happens in one path of > x25_lapb_receive_frame(). When pskb_may_pull() returns false, the > function forgets to decrease the refcnt increased by x25_get_neigh(), > causing a refcnt leak. > > Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns > false. > > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Applied and queued up for -stable, thanks.
diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c index 00e782335cb0..25bf72ee6cad 100644 --- a/net/x25/x25_dev.c +++ b/net/x25/x25_dev.c @@ -115,8 +115,10 @@ int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, goto drop; } - if (!pskb_may_pull(skb, 1)) + if (!pskb_may_pull(skb, 1)) { + x25_neigh_put(nb); return 0; + } switch (skb->data[0]) {