CVE-2025-68331

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer<br /> <br /> When a UAS device is unplugged during data transfer, there is<br /> a probability of a system panic occurring. The root cause is<br /> an access to an invalid memory address during URB callback handling.<br /> Specifically, this happens when the dma_direct_unmap_sg() function<br /> is called within the usb_hcd_unmap_urb_for_dma() interface, but the<br /> sg-&gt;dma_address field is 0 and the sg data structure has already been<br /> freed.<br /> <br /> The SCSI driver sends transfer commands by invoking uas_queuecommand_lck()<br /> in uas.c, using the uas_submit_urbs() function to submit requests to USB.<br /> Within the uas_submit_urbs() implementation, three URBs (sense_urb,<br /> data_urb, and cmd_urb) are sequentially submitted. Device removal may<br /> occur at any point during uas_submit_urbs execution, which may result<br /> in URB submission failure. However, some URBs might have been successfully<br /> submitted before the failure, and uas_submit_urbs will return the -ENODEV<br /> error code in this case. The current error handling directly calls<br /> scsi_done(). In the SCSI driver, this eventually triggers scsi_complete()<br /> to invoke scsi_end_request() for releasing the sgtable. The successfully<br /> submitted URBs, when being unlinked to giveback, call<br /> usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg<br /> unmapping operations since the sg data structure has already been freed.<br /> <br /> This patch modifies the error condition check in the uas_submit_urbs()<br /> function. When a UAS device is removed but one or more URBs have already<br /> been successfully submitted to USB, it avoids immediately invoking<br /> scsi_done() and save the cmnd to devinfo-&gt;cmnd array. If the successfully<br /> submitted URBs is completed before devinfo-&gt;resetting being set, then<br /> the scsi_done() function will be called within uas_try_complete() after<br /> all pending URB operations are finalized. Otherwise, the scsi_done()<br /> function will be called within uas_zap_pending(), which is executed after<br /> usb_kill_anchored_urbs().<br /> <br /> The error handling only takes effect when uas_queuecommand_lck() calls<br /> uas_submit_urbs() and returns the error value -ENODEV . In this case,<br /> the device is disconnected, and the flow proceeds to uas_disconnect(),<br /> where uas_zap_pending() is invoked to call uas_try_complete().