In the Linux kernel, the following vulnerability has been resolved:
usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer
When a UAS device is unplugged during data transfer, there is
a probability of a system panic occurring. The root cause is
an access to an invalid memory address during URB callback handling.
Specifically, this happens when the dma_direct_unmap_sg() function
is called within the usb_hcd_unmap_urb_for_dma() interface, but the
sg->dma_address field is 0 and the sg data structure has already been
freed.
The SCSI driver sends transfer commands by invoking uas_queuecommand_lck()
in uas.c, using the uas_submit_urbs() function to submit requests to USB.
Within the uas_submit_urbs() implementation, three URBs (sense_urb,
data_urb, and cmd_urb) are sequentially submitted. Device removal may
occur at any point during uas_submit_urbs execution, which may result
in URB submission failure. However, some URBs might have been successfully
submitted before the failure, and uas_submit_urbs will return the -ENODEV
error code in this case. The current error handling directly calls
scsi_done(). In the SCSI driver, this eventually triggers scsi_complete()
to invoke scsi_end_request() for releasing the sgtable. The successfully
submitted URBs, when being unlinked to giveback, call
usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg
unmapping operations since the sg data structure has already been freed.
This patch modifies the error condition check in the uas_submit_urbs()
function. When a UAS device is removed but one or more URBs have already
been successfully submitted to USB, it avoids immediately invoking
scsi_done() and save the cmnd to devinfo->cmnd array. If the successfully
submitted URBs is completed before devinfo->resetting being set, then
the scsi_done() function will be called within uas_try_complete() after
all pending URB operations are finalized. Otherwise, the scsi_done()
function will be called within uas_zap_pending(), which is executed after
usb_kill_anchored_urbs().
The error handling only takes effect when uas_queuecommand_lck() calls
uas_submit_urbs() and returns the error value -ENODEV . In this case,
the device is disconnected, and the flow proceeds to uas_disconnect(),
where uas_zap_pending() is invoked to call uas_try_complete().
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
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References
History
Mon, 22 Dec 2025 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer When a UAS device is unplugged during data transfer, there is a probability of a system panic occurring. The root cause is an access to an invalid memory address during URB callback handling. Specifically, this happens when the dma_direct_unmap_sg() function is called within the usb_hcd_unmap_urb_for_dma() interface, but the sg->dma_address field is 0 and the sg data structure has already been freed. The SCSI driver sends transfer commands by invoking uas_queuecommand_lck() in uas.c, using the uas_submit_urbs() function to submit requests to USB. Within the uas_submit_urbs() implementation, three URBs (sense_urb, data_urb, and cmd_urb) are sequentially submitted. Device removal may occur at any point during uas_submit_urbs execution, which may result in URB submission failure. However, some URBs might have been successfully submitted before the failure, and uas_submit_urbs will return the -ENODEV error code in this case. The current error handling directly calls scsi_done(). In the SCSI driver, this eventually triggers scsi_complete() to invoke scsi_end_request() for releasing the sgtable. The successfully submitted URBs, when being unlinked to giveback, call usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg unmapping operations since the sg data structure has already been freed. This patch modifies the error condition check in the uas_submit_urbs() function. When a UAS device is removed but one or more URBs have already been successfully submitted to USB, it avoids immediately invoking scsi_done() and save the cmnd to devinfo->cmnd array. If the successfully submitted URBs is completed before devinfo->resetting being set, then the scsi_done() function will be called within uas_try_complete() after all pending URB operations are finalized. Otherwise, the scsi_done() function will be called within uas_zap_pending(), which is executed after usb_kill_anchored_urbs(). The error handling only takes effect when uas_queuecommand_lck() calls uas_submit_urbs() and returns the error value -ENODEV . In this case, the device is disconnected, and the flow proceeds to uas_disconnect(), where uas_zap_pending() is invoked to call uas_try_complete(). | |
| Title | usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-12-22T16:14:09.243Z
Reserved: 2025-12-16T14:48:05.296Z
Link: CVE-2025-68331
Vulnrichment
No data.
NVD
Status : Received
Published: 2025-12-22T17:16:00.800
Modified: 2025-12-22T17:16:00.800
Link: CVE-2025-68331
Redhat
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OpenCVE Enrichment
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