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econet: fix locking

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econet lacks proper locking. It holds econet_lock only when inserting or
deleting an entry in econet_sklist, not during lookups.

- convert econet_lock from rwlock to spinlock

- use econet_lock in ec_listening_socket() lookup

- use appropriate sock_hold() / sock_put() to avoid corruptions.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-06-09 16:33:05 +00:00 committed by David S. Miller
parent c7de2cf053
commit 0c78a92fbd
1 changed files with 18 additions and 9 deletions
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27
net/econet/af_econet.c
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@ -48,7 +48,7 @@
static const struct proto_ops econet_ops;
static struct hlist_head econet_sklist;
static DEFINE_RWLOCK(econet_lock);
static DEFINE_SPINLOCK(econet_lock);
static DEFINE_MUTEX(econet_mutex);
/* Since there are only 256 possible network numbers (or fewer, depends
@ -98,16 +98,16 @@ struct ec_cb
static void econet_remove_socket(struct hlist_head *list, struct sock *sk)
{
write_lock_bh(&econet_lock);
spin_lock_bh(&econet_lock);
sk_del_node_init(sk);
write_unlock_bh(&econet_lock);
spin_unlock_bh(&econet_lock);
}
static void econet_insert_socket(struct hlist_head *list, struct sock *sk)
{
write_lock_bh(&econet_lock);
spin_lock_bh(&econet_lock);
sk_add_node(sk, list);
write_unlock_bh(&econet_lock);
spin_unlock_bh(&econet_lock);
}
/*
@ -782,15 +782,19 @@ static struct sock *ec_listening_socket(unsigned char port, unsigned char
struct sock *sk;
struct hlist_node *node;
spin_lock(&econet_lock);
sk_for_each(sk, node, &econet_sklist) {
struct econet_sock *opt = ec_sk(sk);
if ((opt->port == port || opt->port == 0) &&
(opt->station == station || opt->station == 0) &&
(opt->net == net || opt->net == 0))
(opt->net == net || opt->net == 0)) {
sock_hold(sk);
goto found;
}
}
sk = NULL;
found:
spin_unlock(&econet_lock);
return sk;
}
@ -852,7 +856,7 @@ static void aun_incoming(struct sk_buff *skb, struct aunhdr *ah, size_t len)
{
struct iphdr *ip = ip_hdr(skb);
unsigned char stn = ntohl(ip->saddr) & 0xff;
struct sock *sk;
struct sock *sk = NULL;
struct sk_buff *newskb;
struct ec_device *edev = skb->dev->ec_ptr;
@ -882,10 +886,13 @@ static void aun_incoming(struct sk_buff *skb, struct aunhdr *ah, size_t len)
}
aun_send_response(ip->saddr, ah->handle, 3, 0);
sock_put(sk);
return;
bad:
aun_send_response(ip->saddr, ah->handle, 4, 0);
if (sk)
sock_put(sk);
}
/*
@ -1050,7 +1057,7 @@ release:
static int econet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
struct ec_framehdr *hdr;
struct sock *sk;
struct sock *sk = NULL;
struct ec_device *edev = dev->ec_ptr;
if (!net_eq(dev_net(dev), &init_net))
@ -1085,10 +1092,12 @@ static int econet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
if (ec_queue_packet(sk, skb, edev->net, hdr->src_stn, hdr->cb,
hdr->port))
goto drop;
sock_put(sk);
return NET_RX_SUCCESS;
drop:
if (sk)
sock_put(sk);
kfree_skb(skb);
return NET_RX_DROP;
}