DEBIAN-CVE-2024-36894

Advisory lineage Upstream: 1 Downstream: 3
Upstream
CVE-2024-36894
Published: 30 May 2024, 16:15
Last modified:28 Apr 2026, 20:28

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.6 MEDIUM
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

30 May 2024, 16:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:28
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix race between aio_cancel() and AIO request complete FFS based applications can utilize the aio_cancel() callback to dequeue pending USB requests submitted to the UDC. There is a scenario where the FFS application issues an AIO cancel call, while the UDC is handling a soft disconnect. For a DWC3 based implementation, the callstack looks like the following: DWC3 Gadget FFS Application dwc3_gadget_soft_disconnect() ... --> dwc3_stop_active_transfers() --> dwc3_gadget_giveback(-ESHUTDOWN) --> ffs_epfile_async_io_complete() ffs_aio_cancel() --> usb_ep_free_request() --> usb_ep_dequeue() There is currently no locking implemented between the AIO completion handler and AIO cancel, so the issue occurs if the completion routine is running in parallel to an AIO cancel call coming from the FFS application. As the completion call frees the USB request (io_data->req) the FFS application is also referencing it for the usb_ep_dequeue() call. This can lead to accessing a stale/hanging pointer. commit b566d38857fc ("usb: gadget: f_fs: use io_data->status consistently") relocated the usb_ep_free_request() into ffs_epfile_async_io_complete(). However, in order to properly implement locking to mitigate this issue, the spinlock can't be added to ffs_epfile_async_io_complete(), as usb_ep_dequeue() (if successfully dequeuing a USB request) will call the function driver's completion handler in the same context. Hence, leading into a deadlock. Fix this issue by moving the usb_ep_free_request() back to ffs_user_copy_worker(), and ensuring that it explicitly sets io_data->req to NULL after freeing it within the ffs->eps_lock. This resolves the race condition above, as the ffs_aio_cancel() routine will not continue attempting to dequeue a request that has already been freed, or the ffs_user_copy_work() not freeing the USB request until the AIO cancel is done referencing it. This fix depends on commit b566d38857fc ("usb: gadget: f_fs: use io_data->status consistently")

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.6CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected Systems

  • debian•linux

    < 5.10.221-1 | < 6.1.99-1 | < 6.8.11-1 | < 6.8.11-1

  • debian•linux-6.1

    < 6.1.119-1~deb11u1

References (1)