From: Jack Pham jackp@codeaurora.org
[ Upstream commit 7de8681be2cde9f6953d3be1fa6ce05f9fe6e637 ]
As per the kernel doc for usb_ep_dequeue(), it states that "this routine is asynchronous, that is, it may return before the completion routine runs". And indeed since v5.0 the dwc3 gadget driver updated its behavior to place dequeued requests on to a cancelled list to be given back later after the endpoint is stopped.
The free_ep() was incorrectly assuming that a request was ready to be freed after calling dequeue which results in a use-after-free in dwc3 when it traverses its cancelled list. Fix this by moving the usb_ep_free_request() call to the callback itself in case the ep is disabled.
Fixes: eb9fecb9e69b0 ("usb: gadget: f_uac2: split out audio core") Reported-and-tested-by: Ferry Toth fntoth@gmail.com Reviewed-and-tested-by: Peter Chen peter.chen@nxp.com Acked-by: Felipe Balbi balbi@kernel.org Signed-off-by: Jack Pham jackp@codeaurora.org Signed-off-by: Jerome Brunet jbrunet@baylibre.com Link: https://lore.kernel.org/r/20210118084642.322510-2-jbrunet@baylibre.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/u_audio.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c index 56906d15fb551..223029fa84459 100644 --- a/drivers/usb/gadget/function/u_audio.c +++ b/drivers/usb/gadget/function/u_audio.c @@ -89,7 +89,12 @@ static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req) struct snd_uac_chip *uac = prm->uac;
/* i/f shutting down */ - if (!prm->ep_enabled || req->status == -ESHUTDOWN) + if (!prm->ep_enabled) { + usb_ep_free_request(ep, req); + return; + } + + if (req->status == -ESHUTDOWN) return;
/* @@ -351,8 +356,14 @@ static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
for (i = 0; i < params->req_number; i++) { if (prm->ureq[i].req) { - usb_ep_dequeue(ep, prm->ureq[i].req); - usb_ep_free_request(ep, prm->ureq[i].req); + if (usb_ep_dequeue(ep, prm->ureq[i].req)) + usb_ep_free_request(ep, prm->ureq[i].req); + /* + * If usb_ep_dequeue() cannot successfully dequeue the + * request, the request will be freed by the completion + * callback. + */ + prm->ureq[i].req = NULL; } }