In the Linux kernel, the following vulnerability has been resolved:
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().
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Affected Vendors & Products
References
History
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-02-28T08:13:14.082Z
Updated: 2024-11-04T11:57:10.727Z
Reserved: 2024-02-27T18:42:55.946Z
Link: CVE-2021-46986
Vulnrichment
Updated: 2024-08-04T05:24:37.910Z
NVD
Status : Awaiting Analysis
Published: 2024-02-28T09:15:37.540
Modified: 2024-02-28T14:06:45.783
Link: CVE-2021-46986
Redhat