Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.15.0 (+22 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 8 | Released |
40 kernels
|
| AlmaLinux 9 | Released |
19 kernels
|
| AlmaLinux 9.2 ESU | Ready For Release | — |
| Amazon Linux 2 | Planned | — |
| Amazon Linux 2023 | Planned | — |
| Amazon Linux 2 5.10 | Will Not Fix | — |
| CentOS 8 | Released |
33 kernels
|
| CloudLinux OS 7h | Released |
54 kernels
|
| CloudLinux OS 8 | Released |
49 kernels
|
| Debian 10 | Planned | — |
| Oracle Linux 6 UEK 4 | Planned | — |
| Oracle Linux 7 UEK 4 | Planned | — |
| Oracle Linux 8 | Released |
64 kernels
|
| Oracle Linux 9 | Released |
25 kernels
|
| RHEL 8 | Released |
61 kernels
|
| RHEL 9 | Released |
19 kernels
|
| Rocky Linux 8 | Released |
34 kernels
|
| Rocky Linux 9 | Released |
18 kernels
|
| Ubuntu 16.04 AWS HWE ESM | Planned | — |
| Ubuntu 16.04 GCP ESM | Planned | — |
| Ubuntu 16.04 HWE ESM | Planned | — |
| Ubuntu 18.04 | Planned | — |
| Ubuntu 18.04 AWS | Planned | — |
| Ubuntu 18.04 GCP | Planned | — |
| Ubuntu 20.04 | Planned | — |
| Ubuntu 22.04 | Planned | — |