[PATCH] net: qrtr: Stop rx_worker before freeing node

[PATCH] net: qrtr: Stop rx_worker before freeing node

[Bjorn Andersson]

As the endpoint is unregistered there might still be work pending to
handle incoming messages, which will result in a use after free
scenario. The plan is to remove the rx_worker, but until then (and for
stable@) ensure that the work is stopped before the node is freed.

Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Cc: stable@vger.kernel.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 net/qrtr/qrtr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 6c8b0f6d28f9..88f98f27ad88 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -150,6 +150,7 @@ static void __qrtr_node_release(struct kref *kref)
 	list_del(&node->item);
 	mutex_unlock(&qrtr_node_lock);
 
+	cancel_work_sync(&node->work);
 	skb_queue_purge(&node->rx_queue);
 	kfree(node);
 }
-- 
2.18.0

Re: [PATCH] net: qrtr: Stop rx_worker before freeing node

[Jakub Kicinski]

On Wed, 18 Sep 2019 10:21:17 -0700, Bjorn Andersson wrote:
> As the endpoint is unregistered there might still be work pending to
> handle incoming messages, which will result in a use after free
> scenario. The plan is to remove the rx_worker, but until then (and for
> stable@) ensure that the work is stopped before the node is freed.
> 
> Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
> Cc: stable@vger.kernel.org
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Thanks! Applied, and queued for 4.9+.

FWIW Dave handles the stable submission himself, so no need to CC
stable on networking patches:
https://www.kernel.org/doc/html/latest/networking/netdev-FAQ.html#q-i-see-a-network-patch-and-i-think-it-should-be-backported-to-stable