From dff081c3602f2fd810f69ef47945a226980dd05d Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Thu, 9 Apr 2026 23:04:16 +0530 Subject: [PATCH] net: qrtr: ns: Fix use-after-free in driver remove() commit 7809fea20c9404bfcfa6112ec08d1fe1d3520beb upstream. In the remove callback, if a packet arrives after destroy_workqueue() is called, but before sock_release(), the qrtr_ns_data_ready() callback will try to queue the work, causing use-after-free issue. Fix this issue by saving the default 'sk_data_ready' callback during qrtr_ns_init() and use it to replace the qrtr_ns_data_ready() callback at the start of remove(). This ensures that even if a packet arrives after destroy_workqueue(), the work struct will not be dereferenced. Note that it is also required to ensure that the RX threads are completed before destroying the workqueue, because the threads could be using the qrtr_ns_data_ready() callback. Cc: stable@vger.kernel.org Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace") Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260409-qrtr-fix-v3-5-00a8a5ff2b51@oss.qualcomm.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/qrtr/ns.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c index 3c513e7ca2d5..c41e7b3b2fc2 100644 --- a/net/qrtr/ns.c +++ b/net/qrtr/ns.c @@ -23,6 +23,7 @@ static struct { struct list_head lookups; struct workqueue_struct *workqueue; struct work_struct work; + void (*saved_data_ready)(struct sock *sk); int local_node; } qrtr_ns; @@ -788,6 +789,7 @@ int qrtr_ns_init(void) goto err_sock; } + qrtr_ns.saved_data_ready = qrtr_ns.sock->sk->sk_data_ready; qrtr_ns.sock->sk->sk_data_ready = qrtr_ns_data_ready; sq.sq_port = QRTR_PORT_CTRL; @@ -828,6 +830,10 @@ int qrtr_ns_init(void) return 0; err_wq: + write_lock_bh(&qrtr_ns.sock->sk->sk_callback_lock); + qrtr_ns.sock->sk->sk_data_ready = qrtr_ns.saved_data_ready; + write_unlock_bh(&qrtr_ns.sock->sk->sk_callback_lock); + destroy_workqueue(qrtr_ns.workqueue); err_sock: sock_release(qrtr_ns.sock); @@ -837,7 +843,12 @@ EXPORT_SYMBOL_GPL(qrtr_ns_init); void qrtr_ns_remove(void) { + write_lock_bh(&qrtr_ns.sock->sk->sk_callback_lock); + qrtr_ns.sock->sk->sk_data_ready = qrtr_ns.saved_data_ready; + write_unlock_bh(&qrtr_ns.sock->sk->sk_callback_lock); + cancel_work_sync(&qrtr_ns.work); + synchronize_net(); destroy_workqueue(qrtr_ns.workqueue); /* sock_release() expects the two references that were put during