Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-50100

Disclosure Date: November 05, 2024
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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 hrtimers have no API for telling when they are queued and the
callback isn’t running, the driver must keep track of this for itself.
That’s what this patch does, adding a new “timer_pending” flag and
setting or clearing it at the appropriate times.

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Technical Analysis