GHSA-CMQF-QGG2-7P77

Vulnerability from github – Published: 2025-12-22 18:30 – Updated: 2025-12-22 18:30
VLAI?
Details

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().

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68331"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-22T17:16:00Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer\n\nWhen a UAS device is unplugged during data transfer, there is\na probability of a system panic occurring. The root cause is\nan access to an invalid memory address during URB callback handling.\nSpecifically, this happens when the dma_direct_unmap_sg() function\nis called within the usb_hcd_unmap_urb_for_dma() interface, but the\nsg-\u003edma_address field is 0 and the sg data structure has already been\nfreed.\n\nThe SCSI driver sends transfer commands by invoking uas_queuecommand_lck()\nin uas.c, using the uas_submit_urbs() function to submit requests to USB.\nWithin the uas_submit_urbs() implementation, three URBs (sense_urb,\ndata_urb, and cmd_urb) are sequentially submitted. Device removal may\noccur at any point during uas_submit_urbs execution, which may result\nin URB submission failure. However, some URBs might have been successfully\nsubmitted before the failure, and uas_submit_urbs will return the -ENODEV\nerror code in this case. The current error handling directly calls\nscsi_done(). In the SCSI driver, this eventually triggers scsi_complete()\nto invoke scsi_end_request() for releasing the sgtable. The successfully\nsubmitted URBs, when being unlinked to giveback, call\nusb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg\nunmapping operations since the sg data structure has already been freed.\n\nThis patch modifies the error condition check in the uas_submit_urbs()\nfunction. When a UAS device is removed but one or more URBs have already\nbeen successfully submitted to USB, it avoids immediately invoking\nscsi_done() and save the cmnd to devinfo-\u003ecmnd array. If the successfully\nsubmitted URBs is completed before devinfo-\u003eresetting being set, then\nthe scsi_done() function will be called within uas_try_complete() after\nall pending URB operations are finalized. Otherwise, the scsi_done()\nfunction will be called within uas_zap_pending(), which is executed after\nusb_kill_anchored_urbs().\n\nThe error handling only takes effect when uas_queuecommand_lck() calls\nuas_submit_urbs() and returns the error value -ENODEV . In this case,\nthe device is disconnected, and the flow proceeds to uas_disconnect(),\nwhere uas_zap_pending() is invoked to call uas_try_complete().",
  "id": "GHSA-cmqf-qgg2-7p77",
  "modified": "2025-12-22T18:30:25Z",
  "published": "2025-12-22T18:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68331"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/26d56a9fcb2014b99e654127960aa0a48a391e3c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b90a8131c83f6f2be69397d2b7d14d217d95d2f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/426edbfc88b22601ea34a441a469092e7b301c52"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6289fc489e94c9beb6be2b502ccc263663733d72"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66ac05e7b0d6bbd1bee9fcf729e20fd4cce86d17"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75f8e2643085db4f7e136fc6b368eb114dd80a64"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3a55221f4de080cb7a91ba10f01c4f708603f8d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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