6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hyunwoo Kim <v4bel@xxxxxxxxx>
commit 2e07e8348ea454615e268222ae3fc240421be768 upstream.
This can cause a race with bt_sock_ioctl() because
bt_sock_recvmsg() gets the skb from sk->sk_receive_queue
and then frees it without holding lock_sock.
A use-after-free for a skb occurs with the following flow.
```
bt_sock_recvmsg() -> skb_recv_datagram() -> skb_free_datagram()
bt_sock_ioctl() -> skb_peek()
```
Add lock_sock to bt_sock_recvmsg() to fix this issue.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Hyunwoo Kim <v4bel@xxxxxxxxx>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/bluetooth/af_bluetooth.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -264,11 +264,14 @@ int bt_sock_recvmsg(struct socket *sock,
if (flags & MSG_OOB)
return -EOPNOTSUPP;
+ lock_sock(sk);
+
skb = skb_recv_datagram(sk, flags, &err);
if (!skb) {
if (sk->sk_shutdown & RCV_SHUTDOWN)
- return 0;
+ err = 0;
+ release_sock(sk);
return err;
}
@@ -294,6 +297,8 @@ int bt_sock_recvmsg(struct socket *sock,
skb_free_datagram(sk, skb);
+ release_sock(sk);
+
if (flags & MSG_TRUNC)
copied = skblen;
