CVE-2021-47452 (GCVE-0-2021-47452)
Vulnerability from cvelistv5
Published
2024-05-22 06:19
Modified
2025-05-04 12:41
Severity ?
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 767d1216bff82507c945e92fe719dff2083bb2f4
Version: 767d1216bff82507c945e92fe719dff2083bb2f4
Version: b110391d1e806167254d3c7ae5d637191d913175
Version: 0a0e5d47670b753d3dbf88f3c77a97a30864d9bd
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