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authorHerbert Xu <herbert@gondor.apana.org.au>2009-04-20 00:35:50 +0200
committerDavid S. Miller <davem@davemloft.net>2009-04-20 12:01:48 +0200
commitc40af84a6726f63e35740d26f841992e8f31f92c (patch)
treedbb8271908d537817915814735cfc2a86130e2f6
parenttun: Only free a netdev when all tun descriptors are closed (diff)
downloadlinux-c40af84a6726f63e35740d26f841992e8f31f92c.tar.xz
linux-c40af84a6726f63e35740d26f841992e8f31f92c.zip
tun: Fix sk_sleep races when attaching/detaching
As the sk_sleep wait queue actually lives in tfile, which may be detached from the tun device, bad things will happen when we use sk_sleep after detaching. Since the tun device is the persistent data structure here (when requested by the user), it makes much more sense to have the wait queue live there. There is no reason to have it in tfile at all since the only time we can wait is if we have a tun attached. In fact we already have a wait queue in tun_struct, so we might as well use it. Reported-by: Eric W. Biederman <ebiederm@xmission.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Tested-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c15
1 files changed, 6 insertions, 9 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 95ae40ab8718..735bf41c654a 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -93,7 +93,6 @@ struct tun_file {
atomic_t count;
struct tun_struct *tun;
struct net *net;
- wait_queue_head_t read_wait;
};
struct tun_sock;
@@ -331,7 +330,7 @@ static void tun_net_uninit(struct net_device *dev)
/* Inform the methods they need to stop using the dev.
*/
if (tfile) {
- wake_up_all(&tfile->read_wait);
+ wake_up_all(&tun->socket.wait);
if (atomic_dec_and_test(&tfile->count))
__tun_detach(tun);
}
@@ -398,7 +397,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
/* Notify and wake up reader process */
if (tun->flags & TUN_FASYNC)
kill_fasync(&tun->fasync, SIGIO, POLL_IN);
- wake_up_interruptible(&tun->tfile->read_wait);
+ wake_up_interruptible(&tun->socket.wait);
return 0;
drop:
@@ -495,7 +494,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
- poll_wait(file, &tfile->read_wait, wait);
+ poll_wait(file, &tun->socket.wait, wait);
if (!skb_queue_empty(&tun->readq))
mask |= POLLIN | POLLRDNORM;
@@ -768,7 +767,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
goto out;
}
- add_wait_queue(&tfile->read_wait, &wait);
+ add_wait_queue(&tun->socket.wait, &wait);
while (len) {
current->state = TASK_INTERRUPTIBLE;
@@ -799,7 +798,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
}
current->state = TASK_RUNNING;
- remove_wait_queue(&tfile->read_wait, &wait);
+ remove_wait_queue(&tun->socket.wait, &wait);
out:
tun_put(tun);
@@ -867,7 +866,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
struct sock *sk;
struct tun_struct *tun;
struct net_device *dev;
- struct tun_file *tfile = file->private_data;
int err;
dev = __dev_get_by_name(net, ifr->ifr_name);
@@ -925,10 +923,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
if (!sk)
goto err_free_dev;
+ init_waitqueue_head(&tun->socket.wait);
sock_init_data(&tun->socket, sk);
sk->sk_write_space = tun_sock_write_space;
sk->sk_sndbuf = INT_MAX;
- sk->sk_sleep = &tfile->read_wait;
tun->sk = sk;
container_of(sk, struct tun_sock, sk)->tun = tun;
@@ -1270,7 +1268,6 @@ static int tun_chr_open(struct inode *inode, struct file * file)
atomic_set(&tfile->count, 0);
tfile->tun = NULL;
tfile->net = get_net(current->nsproxy->net_ns);
- init_waitqueue_head(&tfile->read_wait);
file->private_data = tfile;
return 0;
}