Subject: CVE-2021-47438: net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path

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

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

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

net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path

Prior to this patch in case mlx5_core_destroy_cq() failed it returns
without completing all destroy operations and that leads to memory leak.
Instead, complete the destroy flow before return error.

Also move mlx5_debug_cq_remove() to the beginning of mlx5_core_destroy_cq()
to be symmetrical with mlx5_core_create_cq().

kmemleak complains on:

unreferenced object 0xc000000038625100 (size 64):
  comm "ethtool", pid 28301, jiffies 4298062946 (age 785.380s)
  hex dump (first 32 bytes):
    60 01 48 94 00 00 00 c0 b8 05 34 c3 00 00 00 c0  `.H.......4.....
    02 00 00 00 00 00 00 00 00 db 7d c1 00 00 00 c0  ..........}.....
  backtrace:
    [<000000009e8643cb>] add_res_tree+0xd0/0x270 [mlx5_core]
    [<00000000e7cb8e6c>] mlx5_debug_cq_add+0x5c/0xc0 [mlx5_core]
    [<000000002a12918f>] mlx5_core_create_cq+0x1d0/0x2d0 [mlx5_core]
    [<00000000cef0a696>] mlx5e_create_cq+0x210/0x3f0 [mlx5_core]
    [<000000009c642c26>] mlx5e_open_cq+0xb4/0x130 [mlx5_core]
    [<0000000058dfa578>] mlx5e_ptp_open+0x7f4/0xe10 [mlx5_core]
    [<0000000081839561>] mlx5e_open_channels+0x9cc/0x13e0 [mlx5_core]
    [<0000000009cf05d4>] mlx5e_switch_priv_channels+0xa4/0x230
[mlx5_core]
    [<0000000042bbedd8>] mlx5e_safe_switch_params+0x14c/0x300
[mlx5_core]
    [<0000000004bc9db8>] set_pflag_tx_port_ts+0x9c/0x160 [mlx5_core]
    [<00000000a0553443>] mlx5e_set_priv_flags+0xd0/0x1b0 [mlx5_core]
    [<00000000a8f3d84b>] ethnl_set_privflags+0x234/0x2d0
    [<00000000fd27f27c>] genl_family_rcv_msg_doit+0x108/0x1d0
    [<00000000f495e2bb>] genl_family_rcv_msg+0xe4/0x1f0
    [<00000000646c5c2c>] genl_rcv_msg+0x78/0x120
    [<00000000d53e384e>] netlink_rcv_skb+0x74/0x1a0

The Linux kernel CVE team has assigned CVE-2021-47438 to this issue.

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

	Issue introduced in 3.11 with commit e126ba97dba9 and fixed in 5.10.75 with commit 4f7bddf8c5c0
	Issue introduced in 3.11 with commit e126ba97dba9 and fixed in 5.14.14 with commit ed8aafea4fec
	Issue introduced in 3.11 with commit e126ba97dba9 and fixed in 5.15 with commit 94b960b9deff

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-2021-47438
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/cq.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/4f7bddf8c5c01cac74373443b13a68e1c6723a94
	https://git.kernel.org/stable/c/ed8aafea4fec9c654e63445236e0b505e27ed3a7
	https://git.kernel.org/stable/c/94b960b9deffc02fc0747afc01f72cc62ab099e3