CVE-2021-47266

/// Technical description

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

RDMA/ipoib: Fix warning caused by destroying non-initial netns

After the commit 5ce2dced8e95 ("RDMA/ipoib: Set rtnl_link_ops for ipoib

interfaces"), if the IPoIB device is moved to non-initial netns,

destroying that netns lets the device vanish instead of moving it back to

the initial netns, This is happening because default_device_exit() skips

the interfaces due to having rtnl_link_ops set.

Steps to reporoduce:

ip netns add foo

ip link set mlx5_ib0 netns foo

ip netns delete foo

WARNING: CPU: 1 PID: 704 at net/core/dev.c:11435 netdev_exit+0x3f/0x50

Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT

nf_reject_ipv4 nft_compat nft_counter nft_chain_nat nf_nat nf_conntrack

nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink tun d

fuse

CPU: 1 PID: 704 Comm: kworker/u64:3 Tainted: G S W 5.13.0-rc1+ #1

Hardware name: Dell Inc. PowerEdge R630/02C2CP, BIOS 2.1.5 04/11/2016

Workqueue: netns clean

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References