CVE-2024-36244 net/sched: taprio: extend minimum interval restriction to entire cycle too
A flaw in the Linux kernel's taprio scheduler allows a local attacker to cause a denial of service by configuring invalid cycle times.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-36244?
CVE-2024-36244 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: taprio: extend minimum interval restriction to entire cycle too
It is possible for syzbot to side-step the restriction imposed by the blamed commit in the Fixes: tag, because the taprio UAPI permits a cycle-time different from (and potentially shorter than) the sum of entry intervals.
We need one more restriction, which is that the cycle time itself must be larger than N * ETH_ZLEN bit times, where N is the number of schedule entries. This restriction needs to apply regardless of whether the cycle time came from the user or was the implicit, auto-calculated value, so we move the existing "cycle == 0" check outside the "if "(!new->cycle_time)" branch. This way covers both conditions and scenarios.
Add a selftest which illustrates the issue triggered by syzbot.
Which versions are affected by CVE-2024-36244?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-36244?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-36244 being exploited?
There is no known exploitation of CVE-2024-36244 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-68057, BELL-CVE-2024-36244, DEBIAN-CVE-2024-36244, GHSA-35qp-2m3w-q656, ROOT-OS-DEBIAN-11-CVE-2024-36244, ROOT-OS-UBUNTU-2204-CVE-2024-36244 and 1 more.