Use After Free The advisory has been revoked - it doesn't affect any version of package kernel-zfcpdump-modules-internal (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL9-KERNELZFCPDUMPMODULESINTERNAL-6312793
- published29 Feb 2024
- disclosed28 Feb 2024
Introduced: 28 Feb 2024
CVE-2021-46986 (opens in a new tab)Amendment
The Red Hat security team deemed this advisory irrelevant for RHEL:9.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-modules-internal package and not the kernel-zfcpdump-modules-internal package as distributed by RHEL.
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().
References
- https://access.redhat.com/security/cve/CVE-2021-46986
- https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5
- https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1
- https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139
- https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c