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authorCong Wang <xiyou.wangcong@gmail.com>2018-04-19 21:54:34 -0700
committerDavid S. Miller <davem@davemloft.net>2018-04-22 14:56:22 -0400
commit3a04ce7130a7e5dad4e78d45d50313747f8c830f (patch)
tree52d1a44181da326f2fc5805efbd5875d159bc7b3 /net/llc
parentnet: ethernet: ti: cpsw: fix tx vlan priority mapping (diff)
downloadlinux-dev-3a04ce7130a7e5dad4e78d45d50313747f8c830f.tar.xz
linux-dev-3a04ce7130a7e5dad4e78d45d50313747f8c830f.zip
llc: fix NULL pointer deref for SOCK_ZAPPED
For SOCK_ZAPPED socket, we don't need to care about llc->sap, so we should just skip these refcount functions in this case. Fixes: f7e43672683b ("llc: hold llc_sap before release_sock()") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/llc')
-rw-r--r--net/llc/af_llc.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index 6d29b2b94e84..cb80ebb38311 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -189,7 +189,6 @@ static int llc_ui_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct llc_sock *llc;
- struct llc_sap *sap;
if (unlikely(sk == NULL))
goto out;
@@ -200,15 +199,19 @@ static int llc_ui_release(struct socket *sock)
llc->laddr.lsap, llc->daddr.lsap);
if (!llc_send_disc(sk))
llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
- sap = llc->sap;
- /* Hold this for release_sock(), so that llc_backlog_rcv() could still
- * use it.
- */
- llc_sap_hold(sap);
- if (!sock_flag(sk, SOCK_ZAPPED))
+ if (!sock_flag(sk, SOCK_ZAPPED)) {
+ struct llc_sap *sap = llc->sap;
+
+ /* Hold this for release_sock(), so that llc_backlog_rcv()
+ * could still use it.
+ */
+ llc_sap_hold(sap);
llc_sap_remove_socket(llc->sap, sk);
- release_sock(sk);
- llc_sap_put(sap);
+ release_sock(sk);
+ llc_sap_put(sap);
+ } else {
+ release_sock(sk);
+ }
if (llc->dev)
dev_put(llc->dev);
sock_put(sk);