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tap: double-free in error path in tap_open() 

Double free of skb_array in tap module is causing kernel panic. When
tap_set_queue() fails we free skb_array right away by calling
skb_array_cleanup(). However, later on skb_array_cleanup() is called
again by tap_sock_destruct through sock_put(). This patch fixes that
issue.

Fixes: 362899b872 (macvtap: switch to use skb array)
Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Girish Moodalbail 2017-10-25 00:23:04 -07:00 committed by David S. Miller
parent 5889e2c0e4
commit 78e0ea6791
1 changed files with 9 additions and 9 deletions
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18
drivers/net/tap.c
View File

@ -517,6 +517,10 @@ static int tap_open(struct inode *inode, struct file *file)
&tap_proto, 0); &tap_proto, 0);
if (!q) if (!q)
goto err; goto err;
if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) {
sk_free(&q->sk);
goto err;
}
RCU_INIT_POINTER(q->sock.wq, &q->wq); RCU_INIT_POINTER(q->sock.wq, &q->wq);
init_waitqueue_head(&q->wq.wait); init_waitqueue_head(&q->wq.wait);
@ -540,22 +544,18 @@ static int tap_open(struct inode *inode, struct file *file)
if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG)) if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG))
sock_set_flag(&q->sk, SOCK_ZEROCOPY); sock_set_flag(&q->sk, SOCK_ZEROCOPY);
err = -ENOMEM;
if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL))
goto err_array;
err = tap_set_queue(tap, file, q); err = tap_set_queue(tap, file, q);
if (err) if (err) {
goto err_queue; /* tap_sock_destruct() will take care of freeing skb_array */
goto err_put;
}
dev_put(tap->dev); dev_put(tap->dev);
rtnl_unlock(); rtnl_unlock();
return err; return err;
err_queue: err_put:
skb_array_cleanup(&q->skb_array);
err_array:
sock_put(&q->sk); sock_put(&q->sk);
err: err:
if (tap) if (tap)