CVE-2021-46931: linux kernel vulnerability

What is known

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Wrap the tx reporter dump callback to extract the sq Function mlx5e_tx_reporter_dump_sq() casts its void * argument to struct mlx5e_txqsq *, but in TX-timeout-recovery flow the argument is actually of type struct mlx5e_tx_timeout_ctx *. mlx5_core 0000:08:00.1 enp8s0f1: TX timeout detected mlx5_core 0000:08:00.1 enp8s0f1: TX timeout on queue: 1, SQ: 0x11ec, CQ: 0x146d, SQ Cons: 0x0 SQ Prod: 0x1, usecs since last trans: 21565000 BUG: stack guard page was hit at 0000000093f1a2de (stack is 00000000b66ea0dc..000000004d932dae) kernel stack overflow (page fault): 0000 [#1] SMP NOPTI CPU: 5 PID: 95 Comm: kworker/u20:1 Tainted: G W OE 5.13.0_mlnx #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: mlx5e mlx5e_tx_timeout_work [mlx5_core] RIP: 0010:mlx5e_tx_reporter_dump_sq+0xd3/0x180 [mlx5_core] Call Trace: mlx5e_tx_reporter_dump+0x43/0x1c0 [mlx5_core] devlink_health_do_dump.part.91+0x71/0xd0 devlink_health_report+0x157/0x1b0 mlx5e_reporter_tx_timeout+0xb9/0xf0 [mlx5_core] ? mlx5e_tx_reporter_err_cqe_recover+0x1d0/0x1d0 [mlx5_core] ? mlx5e_health_queue_dump+0xd0/0xd0 [mlx5_core] ? update_load_avg+0x19b/0x550 ? set_next_entity+0x72/0x80 ? pick_next_task_fair+0x227/0x340 ? finish_task_switch+0xa2/0x280 mlx5e_tx_timeout_work+0x83/0xb0 [mlx5_core] process_one_work+0x1de/0x3a0 worker_thread+0x2d/0x3c0 ? process_one_work+0x3a0/0x3a0 kthread+0x115/0x130 ? kthread_park+0x90/0x90 ret_from_fork+0x1f/0x30 --[ end trace 51ccabea504edaff ]--- RIP: 0010:mlx5e_tx_reporter_dump_sq+0xd3/0x180 PKRU: 55555554 Kernel panic - not syncing: Fatal exception Kernel Offset: disabled end Kernel panic - not syncing: Fatal exception To fix this bug add a wrapper for mlx5e_tx_reporter_dump_sq() which extracts the sq from struct mlx5e_tx_timeout_ctx and set it as the TX-timeout-recovery flow dump callback.

Business impact

Successful exploitation of CVE-2021-46931, a medium vulnerability (CVSS 5.5) affecting linux kernel, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether linux kernel is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

• NVD
• Reference
• Reference
• Reference