llc: Fix double accounting of received packets (3446b9d5) · Commits · 戴 / test

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>

net/llc/llc_sap.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -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);

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