net: mctp: usb: fix race between urb completion and rx_retry cancellation
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.8epss 0.1%
exploitation probability
0.1%top 98% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
net: mctp: usb: fix race between urb completion and rx_retry cancellation
It's possible that sequencing between setting ->stopped and cancelling
the rx_retry work (in ndo_stop) could leave us with an urb queued:
T1: ndo_stop T2: rx_retry_work
------------ ----------------
LD: ->stopped => false
ST: ->stopped <= true
usb_kill_urb()
mctp_usb_rx_queue()
usb_submit_urb()
cancel_delayed_work_sync()
That urb completion can then re-schedule rx_retry_work.
Strenghen the sequencing between the stop (preventing another requeue)
and the cancel by updating both atomically under a new rx lock. After
setting ->rx_stopped, and cancelling pending work, we know that the
requeue cannot occur, so all that's left is killing any pending urb.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
Linux · Linux