CVE-2024-26740 net/sched: act_mirred: use the backlog for mirred ingress
A race condition in the Linux kernel's network scheduler can cause a deadlock and system hang when redirecting network traffic.
- 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-2024-26740?
CVE-2024-26740 is a medium-severity vulnerability in Linux kernel, published on 3 Apr 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: act_mirred: use the backlog for mirred ingress
The test Davide added in commit ca22da2fbd69 ("act_mirred: use the backlog for nested calls to mirred ingress") hangs our testing VMs every 10 or so runs, with the familiar tcp_v4_rcv -> tcp_v4_rcv deadlock reported by lockdep.
The problem as previously described by Davide (see Link) is that if we reverse flow of traffic with the redirect (egress -> ingress) we may reach the same socket which generated the packet. And we may still be holding its socket lock. The common solution to such deadlocks is to put the packet in the Rx backlog, rather than run the Rx path inline. Do that for all egress -> ingress reversals, not just once we started to nest mirred calls.
In the past there was a concern that the backlog indirection will lead to loss of error reporting / less accurate stats. But the current workaround does not seem to address the issue.
Weakness: CWE-667
Which versions are affected by CVE-2024-26740?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26740?
Apply the vendor's patch.
Is CVE-2024-26740 being exploited?
There is no known exploitation of CVE-2024-26740 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-58758, BELL-CVE-2024-26740, DEBIAN-CVE-2024-26740, GHSA-37h8-63p8-qhhg, ROOT-OS-DEBIAN-11-CVE-2024-26740, ROOT-OS-DEBIAN-12-CVE-2024-26740 and 2 more.