Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix panic during interface removal
Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished.
But there isn’t a guarantee that the hard if will remain associated with a soft interface up until the work is finished.
This fixes a crash triggered by reboot that looks like this:
Call trace: batadv_v_mesh_free+0xd0/0x4dc [batman_adv] batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x178/0x398 worker_thread+0x2e8/0x4d0 kthread+0xd8/0xdc ret_from_fork+0x10/0x20
(the batadv_v_mesh_free call is misleading, and does not actually happen)
I was able to make the issue happen more reliably by changing hardif_neigh->bat_v.metric_work work to be delayed work. This allowed me to track down and confirm the fix.
[[email protected]: prevent entering batadv_v_elp_get_throughput without soft_iface]
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux-hwe @ 4.15.0 (+8 more)
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix panic during interface removal
Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished.
But there isn’t a guarantee that the hard if will remain associated with a soft interface up until the work is finished.
This fixes a crash triggered by reboot that looks like this:
Call trace: batadv_v_mesh_free+0xd0/0x4dc [batman_adv] batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x178/0x398 worker_thread+0x2e8/0x4d0 kthread+0xd8/0xdc ret_from_fork+0x10/0x20
(the batadv_v_mesh_free call is misleading, and does not actually happen)
I was able to make the issue happen more reliably by changing hardif_neigh->bat_v.metric_work work to be delayed work. This allowed me to track down and confirm the fix.
[[email protected]: prevent entering batadv_v_elp_get_throughput without soft_iface]