CVE-2023-52574 team: fix null-ptr-deref when team device type is changed
A null pointer dereference in the Linux kernel team driver allows local attackers to cause a system crash by changing device types.
- 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-2023-52574?
CVE-2023-52574 is a high-severity vulnerability in Linux kernel, published on 2 Mar 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:
team: fix null-ptr-deref when team device type is changed
Get a null-ptr-deref bug as follows with reproducer [1].
BUG: kernel NULL pointer dereference, address: 0000000000000228 ... RIP: 0010:vlan_dev_hard_header+0x35/0x140 [8021q] ... Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x82/0x150 ? exc_page_fault+0x69/0x150 ? asm_exc_page_fault+0x26/0x30 ? vlan_dev_hard_header+0x35/0x140 [8021q] ? vlan_dev_hard_header+0x8e/0x140 [8021q] neigh_connected_output+0xb2/0x100 ip6_finish_output2+0x1cb/0x520 ? nf_hook_slow+0x43/0xc0 ? ip6_mtu+0x46/0x80 ip6_finish_output+0x2a/0xb0 mld_sendpack+0x18f/0x250 mld_ifc_work+0x39/0x160 process_one_work+0x1e6/0x3f0 worker_thread+0x4d/0x2f0 ? __pfx_worker_thread+0x10/0x10 kthread+0xe5/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30
[1] $ teamd -t team0 -d -c '{"runner": {"name": "loadbalance"}}' $ ip link add name t-dummy type dummy $ ip link add link t-dummy name t-dummy.100 type vlan id 100 $ ip link add name t-nlmon type nlmon $ ip link set t-nlmon master team0 $ ip link set t-nlmon nomaster $ ip link set t-dummy up $ ip link set team0 up $ ip link set t-dummy.100 down $ ip link set t-dummy.100 master team0
When enslave a vlan device to team device and team device type is changed from non-ether to ether, header_ops of team device is changed to vlan_header_ops. That is incorrect and will trigger null-ptr-deref for vlan->real_dev in vlan_dev_hard_header() because team device is not a vlan device.
Cache eth_header_ops in team_setup(), then assign cached header_ops to header_ops of team net device when its type is changed from non-ether to ether to fix the bug.
Weakness: CWE-476
Which versions are affected by CVE-2023-52574?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-52574?
Apply the vendor's patch.
Is CVE-2023-52574 being exploited?
There is no known exploitation of CVE-2023-52574 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-52574, DEBIAN-CVE-2023-52574, GHSA-6vm2-4jg8-fq6m, UBUNTU-CVE-2023-52574.