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authorJack Pham <jackp@codeaurora.org>2021-05-01 02:35:58 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-05-10 14:52:23 +0200
commitbb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139 (patch)
tree886badd4c4b0a58ad6e33a7610f3f9cc2bbcf4be /drivers/usb/dwc3
parent75a41ce46bae6cbe7d3bb2584eb844291d642874 (diff)
usb: dwc3: gadget: Free gadget structure only after freeing endpoints
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@kernel.org> Signed-off-by: Jack Pham <jackp@codeaurora.org> Link: https://lore.kernel.org/r/20210501093558.7375-1-jackp@codeaurora.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/dwc3')
-rw-r--r--drivers/usb/dwc3/gadget.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6eab78f8a1a7..dd1342403bb2 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4062,8 +4062,9 @@ err0:
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);