diff options
| author | Denis Lunev <den@openvz.org> | 2007-04-19 04:05:58 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2007-04-19 04:05:58 +0400 |
| commit | ac57b3a9ce280763296f99e32187a0b4384d9389 (patch) | |
| tree | 5aa81b60abfe3436a5d7d52a93a9c5cb9b9d71a5 /net/netlink | |
| parent | bfb6709d0b239af5e3ce5859aae926e1b79ba84b (diff) | |
| download | linux-ac57b3a9ce280763296f99e32187a0b4384d9389.tar.xz | |
[NETLINK]: Don't attach callback to a going-away netlink socket
There is a race between netlink_dump_start() and netlink_release()
that can lead to the situation when a netlink socket with non-zero
callback is freed.
Here it is:
CPU1: CPU2
netlink_release(): netlink_dump_start():
sk = netlink_lookup(); /* OK */
netlink_remove();
spin_lock(&nlk->cb_lock);
if (nlk->cb) { /* false */
...
}
spin_unlock(&nlk->cb_lock);
spin_lock(&nlk->cb_lock);
if (nlk->cb) { /* false */
...
}
nlk->cb = cb;
spin_unlock(&nlk->cb_lock);
...
sock_orphan(sk);
/*
* proceed with releasing
* the socket
*/
The proposal it to make sock_orphan before detaching the callback
in netlink_release() and to check for the sock to be SOCK_DEAD in
netlink_dump_start() before setting a new callback.
Signed-off-by: Denis Lunev <den@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/af_netlink.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index e73d8f546c6b..c48b0f49f003 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -443,6 +443,7 @@ static int netlink_release(struct socket *sock) return 0; netlink_remove(sk); + sock_orphan(sk); nlk = nlk_sk(sk); spin_lock(&nlk->cb_lock); @@ -457,7 +458,6 @@ static int netlink_release(struct socket *sock) /* OK. Socket is unlinked, and, therefore, no new packets will arrive */ - sock_orphan(sk); sock->sk = NULL; wake_up_interruptible_all(&nlk->wait); @@ -1412,9 +1412,9 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, return -ECONNREFUSED; } nlk = nlk_sk(sk); - /* A dump is in progress... */ + /* A dump or destruction is in progress... */ spin_lock(&nlk->cb_lock); - if (nlk->cb) { + if (nlk->cb || sock_flag(sk, SOCK_DEAD)) { spin_unlock(&nlk->cb_lock); netlink_destroy_callback(cb); sock_put(sk); |