CVE-2022-49195 net: dsa: fix panic on shutdown if multi-chip tree failed to probe
A local attacker can cause a kernel panic during system shutdown if a multi-chip DSA tree fails to probe, leading to denial of service.
- 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-2022-49195?
CVE-2022-49195 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. 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: dsa: fix panic on shutdown if multi-chip tree failed to probe
DSA probing is atypical because a tree of devices must probe all at once, so out of N switches which call dsa_tree_setup_routing_table() during probe, for (N - 1) of them, "complete" will return false and they will exit probing early. The Nth switch will set up the whole tree on their behalf.
The implication is that for (N - 1) switches, the driver binds to the device successfully, without doing anything. When the driver is bound, the ->shutdown() method may run. But if the Nth switch has failed to initialize the tree, there is nothing to do for the (N - 1) driver instances, since the slave devices have not been created, etc. Moreover, dsa_switch_shutdown() expects that the calling @ds has been in fact initialized, so it jumps at dereferencing the various data structures, which is incorrect.
Avoid the ensuing NULL pointer dereferences by simply checking whether the Nth switch has previously set "ds->setup = true" for the switch which is currently shutting down. The entire setup is serialized under dsa2_mutex which we already hold.
Weakness: CWE-476
Which versions are affected by CVE-2022-49195?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49195?
Apply the vendor's patch.
Is CVE-2022-49195 being exploited?
There is no known exploitation of CVE-2022-49195 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49195, GHSA-xpfg-hqmq-gr2w, UBUNTU-CVE-2022-49195.