From: Dean Jenkins Date: Fri, 10 Mar 2017 11:34:45 +0000 (+0000) Subject: Bluetooth: Handle bt_accept_enqueue() socket atomically X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e163376220169170f3945703a600083f1792aaf8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git Bluetooth: Handle bt_accept_enqueue() socket atomically There is a small risk that bt_accept_unlink() runs concurrently with bt_accept_enqueue() on the same socket. This scenario could potentially lead to a NULL pointer dereference of the socket's parent member because the socket can be on the list but the socket's parent member is not yet updated by bt_accept_enqueue(). Therefore, add socket locking inside bt_accept_enqueue() so that the socket is added to the list AND the parent's socket address is set in the socket's parent member. The socket locking ensures that the socket is on the list with a valid non-NULL parent member. Signed-off-by: Dean Jenkins Signed-off-by: Marcel Holtmann --- diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c index 69e1f7d362a8..a374fd27b5e1 100644 --- a/net/bluetooth/af_bluetooth.c +++ b/net/bluetooth/af_bluetooth.c @@ -159,8 +159,10 @@ void bt_accept_enqueue(struct sock *parent, struct sock *sk) BT_DBG("parent %p, sk %p", parent, sk); sock_hold(sk); + lock_sock(sk); list_add_tail(&bt_sk(sk)->accept_q, &bt_sk(parent)->accept_q); bt_sk(sk)->parent = parent; + release_sock(sk); parent->sk_ack_backlog++; } EXPORT_SYMBOL(bt_accept_enqueue);