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5485d62cf5
[ Upstream commit af1c0e4e00 ]
When a frame with NULL DSAP is received, llc_station_rcv is called.
In turn, llc_stat_ev_rx_null_dsap_xid_c is called to check if it is a NULL
XID frame. The return statement of llc_stat_ev_rx_null_dsap_xid_c returns 1
when the incoming frame is not a NULL XID frame and 0 otherwise. Hence, a
NULL XID response is returned unexpectedly, e.g. when the incoming frame is
a NULL TEST command.
To fix the error, simply remove the conditional operator.
A similar error in llc_stat_ev_rx_null_dsap_test_c is also fixed.
Signed-off-by: Chan Shu Tak, Alex <alexchan@task.com.hk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
/*
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* llc_station.c - station component of LLC
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*
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* Copyright (c) 1997 by Procom Technology, Inc.
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* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program can be redistributed or modified under the terms of the
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* GNU General Public License as published by the Free Software Foundation.
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* This program is distributed without any warranty or implied warranty
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* of merchantability or fitness for a particular purpose.
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*
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* See the GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <net/llc.h>
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#include <net/llc_sap.h>
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#include <net/llc_conn.h>
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#include <net/llc_c_ac.h>
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#include <net/llc_s_ac.h>
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#include <net/llc_c_ev.h>
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#include <net/llc_c_st.h>
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#include <net/llc_s_ev.h>
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#include <net/llc_s_st.h>
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#include <net/llc_pdu.h>
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static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
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{
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struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
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return LLC_PDU_IS_CMD(pdu) && /* command PDU */
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LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
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LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
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!pdu->dsap; /* NULL DSAP value */
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}
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static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
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{
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struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
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return LLC_PDU_IS_CMD(pdu) && /* command PDU */
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LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
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LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
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!pdu->dsap; /* NULL DSAP */
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}
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static int llc_station_ac_send_xid_r(struct sk_buff *skb)
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{
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u8 mac_da[ETH_ALEN], dsap;
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int rc = 1;
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struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U,
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sizeof(struct llc_xid_info));
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if (!nskb)
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goto out;
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rc = 0;
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llc_pdu_decode_sa(skb, mac_da);
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llc_pdu_decode_ssap(skb, &dsap);
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llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
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llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
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rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
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if (unlikely(rc))
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goto free;
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dev_queue_xmit(nskb);
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out:
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return rc;
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free:
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kfree_skb(nskb);
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goto out;
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}
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static int llc_station_ac_send_test_r(struct sk_buff *skb)
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{
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u8 mac_da[ETH_ALEN], dsap;
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int rc = 1;
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u32 data_size;
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struct sk_buff *nskb;
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/* The test request command is type U (llc_len = 3) */
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data_size = ntohs(eth_hdr(skb)->h_proto) - 3;
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nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size);
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if (!nskb)
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goto out;
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rc = 0;
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llc_pdu_decode_sa(skb, mac_da);
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llc_pdu_decode_ssap(skb, &dsap);
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llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
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llc_pdu_init_as_test_rsp(nskb, skb);
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rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
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if (unlikely(rc))
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goto free;
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dev_queue_xmit(nskb);
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out:
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return rc;
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free:
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kfree_skb(nskb);
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goto out;
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}
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/**
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* llc_station_rcv - send received pdu to the station state machine
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* @skb: received frame.
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*
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* Sends data unit to station state machine.
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*/
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static void llc_station_rcv(struct sk_buff *skb)
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{
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if (llc_stat_ev_rx_null_dsap_xid_c(skb))
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llc_station_ac_send_xid_r(skb);
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else if (llc_stat_ev_rx_null_dsap_test_c(skb))
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llc_station_ac_send_test_r(skb);
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kfree_skb(skb);
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}
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void __init llc_station_init(void)
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{
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llc_set_station_handler(llc_station_rcv);
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}
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void llc_station_exit(void)
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{
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llc_set_station_handler(NULL);
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}
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