0dcb82254d
llc_sap_put() decreases the refcnt before deleting sap from the global list. Therefore, there is a chance llc_sap_find() could find a sap with zero refcnt in this global list. Close this race condition by checking if refcnt is zero or not in llc_sap_find(), if it is zero then it is being removed so we can just treat it as gone. Reported-by: <syzbot+278893f3f7803871f7ce@syzkaller.appspotmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
162 lines
4.4 KiB
C
162 lines
4.4 KiB
C
#ifndef LLC_H
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#define LLC_H
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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/if.h>
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#include <linux/if_ether.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/rculist_nulls.h>
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#include <linux/hash.h>
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#include <linux/jhash.h>
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#include <linux/atomic.h>
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struct net_device;
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struct packet_type;
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struct sk_buff;
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struct llc_addr {
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unsigned char lsap;
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unsigned char mac[IFHWADDRLEN];
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};
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#define LLC_SAP_STATE_INACTIVE 1
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#define LLC_SAP_STATE_ACTIVE 2
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#define LLC_SK_DEV_HASH_BITS 6
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#define LLC_SK_DEV_HASH_ENTRIES (1<<LLC_SK_DEV_HASH_BITS)
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#define LLC_SK_LADDR_HASH_BITS 6
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#define LLC_SK_LADDR_HASH_ENTRIES (1<<LLC_SK_LADDR_HASH_BITS)
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/**
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* struct llc_sap - Defines the SAP component
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*
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* @station - station this sap belongs to
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* @state - sap state
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* @p_bit - only lowest-order bit used
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* @f_bit - only lowest-order bit used
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* @laddr - SAP value in this 'lsap'
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* @node - entry in station sap_list
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* @sk_list - LLC sockets this one manages
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*/
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struct llc_sap {
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unsigned char state;
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unsigned char p_bit;
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unsigned char f_bit;
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refcount_t refcnt;
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int (*rcv_func)(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt,
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struct net_device *orig_dev);
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struct llc_addr laddr;
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struct list_head node;
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spinlock_t sk_lock;
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int sk_count;
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struct hlist_nulls_head sk_laddr_hash[LLC_SK_LADDR_HASH_ENTRIES];
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struct hlist_head sk_dev_hash[LLC_SK_DEV_HASH_ENTRIES];
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};
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static inline
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struct hlist_head *llc_sk_dev_hash(struct llc_sap *sap, int ifindex)
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{
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return &sap->sk_dev_hash[ifindex % LLC_SK_DEV_HASH_ENTRIES];
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}
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static inline
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u32 llc_sk_laddr_hashfn(struct llc_sap *sap, const struct llc_addr *laddr)
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{
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return hash_32(jhash(laddr->mac, sizeof(laddr->mac), 0),
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LLC_SK_LADDR_HASH_BITS);
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}
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static inline
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struct hlist_nulls_head *llc_sk_laddr_hash(struct llc_sap *sap,
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const struct llc_addr *laddr)
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{
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return &sap->sk_laddr_hash[llc_sk_laddr_hashfn(sap, laddr)];
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}
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#define LLC_DEST_INVALID 0 /* Invalid LLC PDU type */
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#define LLC_DEST_SAP 1 /* Type 1 goes here */
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#define LLC_DEST_CONN 2 /* Type 2 goes here */
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extern struct list_head llc_sap_list;
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int llc_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
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struct net_device *orig_dev);
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int llc_mac_hdr_init(struct sk_buff *skb, const unsigned char *sa,
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const unsigned char *da);
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void llc_add_pack(int type,
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void (*handler)(struct llc_sap *sap, struct sk_buff *skb));
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void llc_remove_pack(int type);
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void llc_set_station_handler(void (*handler)(struct sk_buff *skb));
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struct llc_sap *llc_sap_open(unsigned char lsap,
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int (*rcv)(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt,
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struct net_device *orig_dev));
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static inline void llc_sap_hold(struct llc_sap *sap)
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{
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refcount_inc(&sap->refcnt);
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}
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static inline bool llc_sap_hold_safe(struct llc_sap *sap)
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{
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return refcount_inc_not_zero(&sap->refcnt);
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}
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void llc_sap_close(struct llc_sap *sap);
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static inline void llc_sap_put(struct llc_sap *sap)
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{
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if (refcount_dec_and_test(&sap->refcnt))
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llc_sap_close(sap);
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}
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struct llc_sap *llc_sap_find(unsigned char sap_value);
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int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
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unsigned char *dmac, unsigned char dsap);
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void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb);
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void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb);
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void llc_station_init(void);
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void llc_station_exit(void);
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#ifdef CONFIG_PROC_FS
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int llc_proc_init(void);
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void llc_proc_exit(void);
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#else
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#define llc_proc_init() (0)
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#define llc_proc_exit() do { } while(0)
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#endif /* CONFIG_PROC_FS */
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#ifdef CONFIG_SYSCTL
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int llc_sysctl_init(void);
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void llc_sysctl_exit(void);
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extern int sysctl_llc2_ack_timeout;
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extern int sysctl_llc2_busy_timeout;
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extern int sysctl_llc2_p_timeout;
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extern int sysctl_llc2_rej_timeout;
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#else
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#define llc_sysctl_init() (0)
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#define llc_sysctl_exit() do { } while(0)
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#endif /* CONFIG_SYSCTL */
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#endif /* LLC_H */
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