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authorGirish Moodalbail <girish.moodalbail@oracle.com>2017-10-25 10:23:04 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-26 11:57:39 +0300
commit78e0ea6791d7baafb8a0ca82b1bd0c7b3453c919 (patch)
tree6be52d342cd4ea32359a90ec7aabc96d9b08dd40 /drivers/net/tap.c
parent5889e2c0e441d84060e66211ed5c4517ca591167 (diff)
downloadlinux-78e0ea6791d7baafb8a0ca82b1bd0c7b3453c919.tar.xz
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: 362899b8725b35e3 (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>
Diffstat (limited to 'drivers/net/tap.c')
-rw-r--r--drivers/net/tap.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 21b71ae947fd..98ee6cc2875d 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -517,6 +517,10 @@ static int tap_open(struct inode *inode, struct file *file)
&tap_proto, 0);
if (!q)
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);
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))
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);
- if (err)
- goto err_queue;
+ if (err) {
+ /* tap_sock_destruct() will take care of freeing skb_array */
+ goto err_put;
+ }
dev_put(tap->dev);
rtnl_unlock();
return err;
-err_queue:
- skb_array_cleanup(&q->skb_array);
-err_array:
+err_put:
sock_put(&q->sk);
err:
if (tap)