Subject: CVE-2022-48884: net/mlx5: Fix command stats access after free

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

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

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix command stats access after free

Command may fail while driver is reloading and can't accept FW commands
till command interface is reinitialized. Such command failure is being
logged to command stats. This results in NULL pointer access as command
stats structure is being freed and reallocated during mlx5 devlink
reload (see kernel log below).

Fix it by making command stats statically allocated on driver probe.

Kernel log:
[ 2394.808802] BUG: unable to handle kernel paging request at 000000000002a9c0
[ 2394.810610] PGD 0 P4D 0
[ 2394.811811] Oops: 0002 [#1] SMP NOPTI
...
[ 2394.815482] RIP: 0010:native_queued_spin_lock_slowpath+0x183/0x1d0
...
[ 2394.829505] Call Trace:
[ 2394.830667]  _raw_spin_lock_irq+0x23/0x26
[ 2394.831858]  cmd_status_err+0x55/0x110 [mlx5_core]
[ 2394.833020]  mlx5_access_reg+0xe7/0x150 [mlx5_core]
[ 2394.834175]  mlx5_query_port_ptys+0x78/0xa0 [mlx5_core]
[ 2394.835337]  mlx5e_ethtool_get_link_ksettings+0x74/0x590 [mlx5_core]
[ 2394.836454]  ? kmem_cache_alloc_trace+0x140/0x1c0
[ 2394.837562]  __rh_call_get_link_ksettings+0x33/0x100
[ 2394.838663]  ? __rtnl_unlock+0x25/0x50
[ 2394.839755]  __ethtool_get_link_ksettings+0x72/0x150
[ 2394.840862]  duplex_show+0x6e/0xc0
[ 2394.841963]  dev_attr_show+0x1c/0x40
[ 2394.843048]  sysfs_kf_seq_show+0x9b/0x100
[ 2394.844123]  seq_read+0x153/0x410
[ 2394.845187]  vfs_read+0x91/0x140
[ 2394.846226]  ksys_read+0x4f/0xb0
[ 2394.847234]  do_syscall_64+0x5b/0x1a0
[ 2394.848228]  entry_SYSCALL_64_after_hwframe+0x65/0xca

The Linux kernel CVE team has assigned CVE-2022-48884 to this issue.

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

	Issue introduced in 5.18 with commit 34f46ae0d4b3 and fixed in 6.1.7 with commit ddf458641a51
	Issue introduced in 5.18 with commit 34f46ae0d4b3 and fixed in 6.2 with commit da2e552b469a

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-2022-48884
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/cmd.c
	include/linux/mlx5/driver.h

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/ddf458641a511e7dff19f3bf0cbbc5dd9fe08ce5
	https://git.kernel.org/stable/c/da2e552b469a0cd130ff70a88ccc4139da428a65