CVE - CVE-2021-47272

CVE-ID
CVE-2021-47272	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: Bail from dwc3_gadget_exit() if dwc->gadget is NULL There exists a possible scenario in which dwc3_gadget_init() can fail: during during host -> peripheral mode switch in dwc3_set_mode(), and a pending gadget driver fails to bind. Then, if the DRD undergoes another mode switch from peripheral->host the resulting dwc3_gadget_exit() will attempt to reference an invalid and dangling dwc->gadget pointer as well as call dma_free_coherent() on unmapped DMA pointers. The exact scenario can be reproduced as follows: - Start DWC3 in peripheral mode - Configure ConfigFS gadget with FunctionFS instance (or use g_ffs) - Run FunctionFS userspace application (open EPs, write descriptors, etc) - Bind gadget driver to DWC3's UDC - Switch DWC3 to host mode => dwc3_gadget_exit() is called. usb_del_gadget() will put the ConfigFS driver instance on the gadget_driver_pending_list - Stop FunctionFS application (closes the ep files) - Switch DWC3 to peripheral mode => dwc3_gadget_init() fails as usb_add_gadget() calls check_pending_gadget_drivers() and attempts to rebind the UDC to the ConfigFS gadget but fails with -19 (-ENODEV) because the FFS instance is not in FFS_ACTIVE state (userspace has not re-opened and written the descriptors yet, i.e. desc_ready!=0). - Switch DWC3 back to host mode => dwc3_gadget_exit() is called again, but this time dwc->gadget is invalid. Although it can be argued that userspace should take responsibility for ensuring that the FunctionFS application be ready prior to allowing the composite driver bind to the UDC, failure to do so should not result in a panic from the kernel driver. Fix this by setting dwc->gadget to NULL in the failure path of dwc3_gadget_init() and add a check to dwc3_gadget_exit() to bail out unless the gadget pointer is valid.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/03715ea2e3dbbc56947137ce3b4ac18a726b2f87 URL:https://git.kernel.org/stable/c/03715ea2e3dbbc56947137ce3b4ac18a726b2f87 MISC:https://git.kernel.org/stable/c/4aad390363d2b9b3e92428dd34d27bb7ea8f1ee8 URL:https://git.kernel.org/stable/c/4aad390363d2b9b3e92428dd34d27bb7ea8f1ee8 MISC:https://git.kernel.org/stable/c/851dee5a5da56564a70290713aee665403bb0b24 URL:https://git.kernel.org/stable/c/851dee5a5da56564a70290713aee665403bb0b24
Assigning CNA
kernel.org
Date Record Created
20240521	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240521)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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