2023-03-09 18:13:23

by Fedor Pchelkin

Subject: [PATCH 4.14/4.19/5.4/5.10/5.15 0/1] Bluetooth: hci_sock: purge socket queues in the destruct() callback

Syzkaller reports a memory leak in mgmt_cmd_complete(). The issue can be
triggered on 4.14/4.19/5.4/5.10/5.15 stable branches. The following fixing
patch can be cleanly applied to them.

2023-03-09 18:13:26

by Fedor Pchelkin

Subject: [PATCH 4.14/4.19/5.4/5.10/5.15 1/1] Bluetooth: hci_sock: purge socket queues in the destruct() callback

From: Nguyen Dinh Phi <[email protected]>

commit 709fca500067524381e28a5f481882930eebac88 upstream.

The receive path may take the socket right before hci_sock_release(),
but it may enqueue the packets to the socket queues after the call to
skb_queue_purge(), therefore the socket can be destroyed without clear
its queues completely.

Moving these skb_queue_purge() to the hci_sock_destruct() will fix this
issue, because nothing is referencing the socket at this point.

Signed-off-by: Nguyen Dinh Phi <[email protected]>
Reported-by: [email protected]
Signed-off-by: Marcel Holtmann <[email protected]>
Signed-off-by: Fedor Pchelkin <[email protected]>
---
net/bluetooth/hci_sock.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index f1128c2134f0..3f92a21cabe8 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -888,10 +888,6 @@ static int hci_sock_release(struct socket *sock)
}

sock_orphan(sk);
-
- skb_queue_purge(&sk->sk_receive_queue);
- skb_queue_purge(&sk->sk_write_queue);
-
release_sock(sk);
sock_put(sk);
return 0;
@@ -2012,6 +2008,12 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname,
return err;
}

+static void hci_sock_destruct(struct sock *sk)
+{
+ skb_queue_purge(&sk->sk_receive_queue);
+ skb_queue_purge(&sk->sk_write_queue);
+}
+
static const struct proto_ops hci_sock_ops = {
.family = PF_BLUETOOTH,
.owner = THIS_MODULE,
@@ -2065,6 +2067,7 @@ static int hci_sock_create(struct net *net, struct socket *sock, int protocol,

sock->state = SS_UNCONNECTED;
sk->sk_state = BT_OPEN;
+ sk->sk_destruct = hci_sock_destruct;

bt_sock_link(&hci_sk_list, sk);
return 0;
--
2.34.1

2023-03-10 11:50:33

by Greg Kroah-Hartman

Subject: Re: [PATCH 4.14/4.19/5.4/5.10/5.15 1/1] Bluetooth: hci_sock: purge socket queues in the destruct() callback

On Thu, Mar 09, 2023 at 09:12:51PM +0300, Fedor Pchelkin wrote:
> From: Nguyen Dinh Phi <[email protected]>
>
> commit 709fca500067524381e28a5f481882930eebac88 upstream.
>
> The receive path may take the socket right before hci_sock_release(),
> but it may enqueue the packets to the socket queues after the call to
> skb_queue_purge(), therefore the socket can be destroyed without clear
> its queues completely.
>
> Moving these skb_queue_purge() to the hci_sock_destruct() will fix this
> issue, because nothing is referencing the socket at this point.
>
> Signed-off-by: Nguyen Dinh Phi <[email protected]>
> Reported-by: [email protected]
> Signed-off-by: Marcel Holtmann <[email protected]>
> Signed-off-by: Fedor Pchelkin <[email protected]>
> ---
> net/bluetooth/hci_sock.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
> index f1128c2134f0..3f92a21cabe8 100644
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -888,10 +888,6 @@ static int hci_sock_release(struct socket *sock)
> }
>
> sock_orphan(sk);
> -
> - skb_queue_purge(&sk->sk_receive_queue);
> - skb_queue_purge(&sk->sk_write_queue);
> -
> release_sock(sk);
> sock_put(sk);
> return 0;
> @@ -2012,6 +2008,12 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname,
> return err;
> }
>
> +static void hci_sock_destruct(struct sock *sk)
> +{
> + skb_queue_purge(&sk->sk_receive_queue);
> + skb_queue_purge(&sk->sk_write_queue);
> +}
> +
> static const struct proto_ops hci_sock_ops = {
> .family = PF_BLUETOOTH,
> .owner = THIS_MODULE,
> @@ -2065,6 +2067,7 @@ static int hci_sock_create(struct net *net, struct socket *sock, int protocol,
>
> sock->state = SS_UNCONNECTED;
> sk->sk_state = BT_OPEN;
> + sk->sk_destruct = hci_sock_destruct;
>
> bt_sock_link(&hci_sk_list, sk);
> return 0;
> --
> 2.34.1
>

Now queued up, thanks.

greg k-h