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authorCong Wang <xiyou.wangcong@gmail.com>2018-12-29 13:56:38 -0800
committerDavid S. Miller <davem@davemloft.net>2018-12-30 20:24:16 -0800
commit7314f5480f3e37e570104dc5e0f28823ef849e72 (patch)
treefbe09ebb46b892704e3cf8b0d7cafc963aa6c0b4
parentd5c7c745f254c6cb98b3b3f15fe789b8bd770c72 (diff)
netrom: fix locking in nr_find_socket()
nr_find_socket(), nr_find_peer() and nr_find_listener() lock the sock after finding it in the global list. However, the call path requires BH disabled for the sock lock consistently. Actually the locking is unnecessary at this point, we can just hold the sock refcnt to make sure it is not gone after we unlock the global list, and lock it later only when needed. Reported-and-tested-by: syzbot+f621cda8b7e598908efa@syzkaller.appspotmail.com Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/netrom/af_netrom.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index 03f37c4e64fe..1d3144d19903 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -153,7 +153,7 @@ static struct sock *nr_find_listener(ax25_address *addr)
sk_for_each(s, &nr_list)
if (!ax25cmp(&nr_sk(s)->source_addr, addr) &&
s->sk_state == TCP_LISTEN) {
- bh_lock_sock(s);
+ sock_hold(s);
goto found;
}
s = NULL;
@@ -174,7 +174,7 @@ static struct sock *nr_find_socket(unsigned char index, unsigned char id)
struct nr_sock *nr = nr_sk(s);
if (nr->my_index == index && nr->my_id == id) {
- bh_lock_sock(s);
+ sock_hold(s);
goto found;
}
}
@@ -198,7 +198,7 @@ static struct sock *nr_find_peer(unsigned char index, unsigned char id,
if (nr->your_index == index && nr->your_id == id &&
!ax25cmp(&nr->dest_addr, dest)) {
- bh_lock_sock(s);
+ sock_hold(s);
goto found;
}
}
@@ -224,7 +224,7 @@ static unsigned short nr_find_next_circuit(void)
if (i != 0 && j != 0) {
if ((sk=nr_find_socket(i, j)) == NULL)
break;
- bh_unlock_sock(sk);
+ sock_put(sk);
}
id++;
@@ -920,6 +920,7 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
}
if (sk != NULL) {
+ bh_lock_sock(sk);
skb_reset_transport_header(skb);
if (frametype == NR_CONNACK && skb->len == 22)
@@ -929,6 +930,7 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
ret = nr_process_rx_frame(sk, skb);
bh_unlock_sock(sk);
+ sock_put(sk);
return ret;
}
@@ -960,10 +962,12 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
(make = nr_make_new(sk)) == NULL) {
nr_transmit_refusal(skb, 0);
if (sk)
- bh_unlock_sock(sk);
+ sock_put(sk);
return 0;
}
+ bh_lock_sock(sk);
+
window = skb->data[20];
skb->sk = make;
@@ -1016,6 +1020,7 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
sk->sk_data_ready(sk);
bh_unlock_sock(sk);
+ sock_put(sk);
nr_insert_socket(make);

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