From: Jack Pham <jackp@xxxxxxxxxxxxxx>
[ Upstream commit bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 ]
As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
dynamically") the dwc3_gadget_release() was added which will free
the dwc->gadget structure upon the device's removal when
usb_del_gadget_udc() is called in dwc3_gadget_exit().
However, simply freeing the gadget results a dangling pointer
situation: the endpoints created in dwc3_gadget_init_endpoints()
have their dep->endpoint.ep_list members chained off the list_head
anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
the first dwc3_ep in the list now has a dangling prev pointer and
likewise for the next pointer of the dwc3_ep at the tail of the list.
The dwc3_gadget_free_endpoints() that follows will result in a
use-after-free when it calls list_del().
This was caught by enabling KASAN and performing a driver unbind.
The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
callback for dwc3") also exposes this as a panic during shutdown.
There are a few possibilities to fix this. One could be to perform
a list_del() of the gadget->ep_list itself which removes it from
the rest of the dwc3_ep chain.
Another approach is what this patch does, by splitting up the
usb_del_gadget_udc() call into its separate "del" and "put"
components. This allows dwc3_gadget_free_endpoints() to be
called before the gadget is finally freed with usb_put_gadget().
Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
Reviewed-by: Peter Chen <peter.chen@xxxxxxxxxx>
Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210501093558.7375-1-jackp@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 84d1487e9f06..dab9b5fd15a9 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3948,8 +3948,9 @@ int dwc3_gadget_init(struct dwc3 *dwc)
void dwc3_gadget_exit(struct dwc3 *dwc)
{
- usb_del_gadget_udc(dwc->gadget);
+ usb_del_gadget(dwc->gadget);
dwc3_gadget_free_endpoints(dwc);
+ usb_put_gadget(dwc->gadget);
dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
dwc->bounce_addr);
kfree(dwc->setup_buf);
--
2.30.2
