Subject: CVE-2021-46931: net/mlx5e: Wrap the tx reporter dump callback to extract the sq

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2021-46931 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.7 with commit 5f29458b77d5 and fixed in 5.10.90 with commit 73665165b64a
	Issue introduced in 5.7 with commit 5f29458b77d5 and fixed in 5.15.13 with commit 07f13d58a8ec
	Issue introduced in 5.7 with commit 5f29458b77d5 and fixed in 5.16 with commit 918fc3855a65

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-46931
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/73665165b64a8f3c5b3534009a69be55bb744f05
	https://git.kernel.org/stable/c/07f13d58a8ecc3baf9a488588fb38c5cb0db484f
	https://git.kernel.org/stable/c/918fc3855a6507a200e9cf22c20be852c0982687