[PATCH AUTOSEL 5.15 04/46] usb: cdns3 fix use-after-free at workaround 2

[Sasha Levin]

From: Frank Li <Frank.Li@xxxxxxx>

[ Upstream commit 7d602f30149a117eea260208b1661bc404c21dfd ]

BUG: KFENCE: use-after-free read in __list_del_entry_valid+0x10/0xac

cdns3_wa2_remove_old_request()
{
	...
	kfree(priv_req->request.buf);
	cdns3_gadget_ep_free_request(&priv_ep->endpoint, &priv_req->request);
	list_del_init(&priv_req->list);
	^^^ use after free
	...
}

cdns3_gadget_ep_free_request() free the space pointed by priv_req,
but priv_req is used in the following list_del_init().

This patch move list_del_init() before cdns3_gadget_ep_free_request().

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Signed-off-by: Faqiang Zhu <faqiang.zhu@xxxxxxx>
Link: https://lore.kernel.org/r/20220608190430.2814358-1-Frank.Li@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/cdns3/cdns3-gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index d6d515d598dc..c4f90b124e55 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -625,9 +625,9 @@ static void cdns3_wa2_remove_old_request(struct cdns3_endpoint *priv_ep)
 		trace_cdns3_wa2(priv_ep, "removes eldest request");
 
 		kfree(priv_req->request.buf);
+		list_del_init(&priv_req->list);
 		cdns3_gadget_ep_free_request(&priv_ep->endpoint,
 					     &priv_req->request);
-		list_del_init(&priv_req->list);
 		--priv_ep->wa2_counter;
 
 		if (!chain)
-- 
2.35.1