CVE-2024-50100

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

USB: gadget: dummy-hcd: Fix "task hung" problem

The syzbot fuzzer has been encountering "task hung" problems ever

since the dummy-hcd driver was changed to use hrtimers instead of

regular timers. It turns out that the problems are caused by a subtle

difference between the timer_pending() and hrtimer_active() APIs.

The changeover blindly replaced the first by the second. However,

timer_pending() returns True when the timer is queued but not when its

callback is running, whereas hrtimer_active() returns True when the

hrtimer is queued _or_ its callback is running. This difference

occasionally caused dummy_urb_enqueue() to think that the callback

routine had not yet started when in fact it was almost finished. As a

result the hrtimer was not restarted, which made it impossible for the

driver to dequeue later the URB that was just enqueued. This caused

usb_kill_urb() to hang, and things got worse from there.

Since

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References