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CVE-2021-47452 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: skip netdev events generated on netns removal syzbot reported following (harmless) WARN: WARNING: CPU: 1 PID: 2648 at net/netfilter/core.c:468 nft_netdev_unregister_hooks net/netfilter/nf_tables_api.c:230 [inline] nf_tables_unregister_hook include/net/netfilter/nf_tables.h:1090 [inline] __nft_release_basechain+0x138/0x640 net/netfilter/nf_tables_api.c:9524 nft_netdev_event net/netfilter/nft_chain_filter.c:351 [inline] nf_tables_netdev_event+0x521/0x8a0 net/netfilter/nft_chain_filter.c:382 reproducer: unshare -n bash -c 'ip link add br0 type bridge; nft add table netdev t ; \ nft add chain netdev t ingress \{ type filter hook ingress device "br0" \ priority 0\; policy drop\; \}' Problem is that when netns device exit hooks create the UNREGISTER event, the .pre_exit hook for nf_tables core has already removed the base hook. Notifier attempts to do this again. The need to do base hook unregister unconditionally was needed in the past, because notifier was last stage where reg->dev dereference was safe. Now that nf_tables does the hook removal in .pre_exit, this isn't needed anymore.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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Hyperlink Resource
https://git.kernel.org/stable/c/68a3765c659f809dcaac20030853a054646eb739
https://git.kernel.org/stable/c/68a3765c659f809dcaac20030853a054646eb739
https://git.kernel.org/stable/c/90c7c58aa2bd02c65a4c63b7dfe0b16eab12cf9f
https://git.kernel.org/stable/c/90c7c58aa2bd02c65a4c63b7dfe0b16eab12cf9f

Weakness Enumeration

CWE-ID CWE Name Source

Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-47452
NVD Published Date:
05/22/2024
NVD Last Modified:
11/21/2024
Source:
kernel.org