llc: Fix double accounting of received packets

llc_sap_rcv was being preceded by skb_set_owner_r, then calling
llc_state_process that calls sock_queue_rcv_skb, that in turn calls
skb_set_owner_r again making the space allowed to be used by the socket to be
leaked, making the socket to get stuck.

Fix it by setting skb->sk at llc_sap_rcv and leave the accounting to be done
only at sock_queue_rcv_skb.

Reported-by: Dmitry Petukhov <dmgenp@gmail.com>
Tested-by: Dmitry Petukhov <dmgenp@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
index e2ddde755019c6cf7e73ab1614352026429df006..008de1fc42ca79b07cafed68ccb3e7e396161dc9 100644 (file)
--- a/net/llc/llc_sap.c
+++ b/net/llc/llc_sap.c
@@ -286,12 +286,14 @@ void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
  *
  *     Sends received pdus to the sap state machine.
  */
-static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
+static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
+                       struct sock *sk)
 {
        struct llc_sap_state_ev *ev = llc_sap_ev(skb);
 
        ev->type   = LLC_SAP_EV_TYPE_PDU;
        ev->reason = 0;
+       skb->sk = sk;
        llc_sap_state_process(sap, skb);
 }
 
@@ -360,8 +362,7 @@ static void llc_sap_mcast(struct llc_sap *sap,
                        break;
 
                sock_hold(sk);
-               skb_set_owner_r(skb1, sk);
-               llc_sap_rcv(sap, skb1);
+               llc_sap_rcv(sap, skb1, sk);
                sock_put(sk);
        }
        read_unlock_bh(&sap->sk_list.lock);
@@ -381,8 +382,7 @@ void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
        } else {
                struct sock *sk = llc_lookup_dgram(sap, &laddr);
                if (sk) {
-                       skb_set_owner_r(skb, sk);
-                       llc_sap_rcv(sap, skb);
+                       llc_sap_rcv(sap, skb, sk);
                        sock_put(sk);
                } else
                        kfree_skb(skb);