[PATCH 5.4 350/389] usb: cdns3 fix use-after-free at workaround 2

Greg Kroah-Hartman
2022-08-23T11:59:23Z

From: Frank Li <Frank.Li@nxp.com>

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

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 296f2ee1b680..a9399f2b3930 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -549,9 +549,9 @@ 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