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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2024-56655

netfilter: nf_tables: do not defer rule destruction via call_rcu

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: do not defer rule destruction via call_rcu nf_tables_chain_destroy can sleep, it can't be used from call_rcu callbacks. Moreover, nf_tables_rule_release() is only safe for error unwinding, while transaction mutex is held and the to-be-desroyed rule was not exposed to either dataplane or dumps, as it deactives+frees without the required synchronize_rcu() in-between. nft_rule_expr_deactivate() callbacks will change ->use counters of other chains/sets, see e.g. nft_lookup .deactivate callback, these must be serialized via transaction mutex. Also add a few lockdep asserts to make this more explicit. Calling synchronize_rcu() isn't ideal, but fixing this without is hard and way more intrusive. As-is, we can get: WARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x.. Workqueue: events nf_tables_trans_destroy_work RIP: 0010:nft_set_destroy+0x3fe/0x5c0 Call Trace: <TASK> nf_tables_trans_destroy_work+0x6b7/0xad0 process_one_work+0x64a/0xce0 worker_thread+0x613/0x10d0 In case the synchronize_rcu becomes an issue, we can explore alternatives. One way would be to allocate nft_trans_rule objects + one nft_trans_chain object, deactivate the rules + the chain and then defer the freeing to the nft destroy workqueue. We'd still need to keep the synchronize_rcu path as a fallback to handle -ENOMEM corner cases though.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 9eee6097ffb26cdd2adb988c0d378fa0d650c737 to < 5146c27b2780aac59876a887a5f4e793b8949862affected
  • 558f503f707f481bbf40efa74a938b8021df841d to < 2991dc357a28b61c13ed1f7b59e9251e2b4562fbaffected
  • a394c160d57f4b083bd904a22802f6fb7f5b3cea to < b8d8f53e1858178882b881b8c09f94ef0e83bf76affected
  • e6c32a64d61184c2bdf89442b3d31ef530afba34 to < b0f013bebf94fe7ae75e5a53be2f2bd1cc1841e3affected
  • bfd05c68e4c6320304e9f371ffa356b6e4b9cc53 to < 27f0574253f6c24c8ee4e3f0a685b75ed3a256edaffected
  • c03d278fdf35e73dd0ec543b9b556876b9d9a8dc to < 7cf0bd232b565d9852cb25fd094f77254773e048affected
  • c03d278fdf35e73dd0ec543b9b556876b9d9a8dc to < b04df3da1b5c6f6dc7cdccc37941740c078c4043affected
  • cb401e5799e0acacb405f2128097e9c4ccf82f8aaffected
  • 6.6.61 to < 6.6.67affected
  • 6.11.8 to < 6.12affected

Linux Linux

Default version status: affected

  • 6.12affected
  • 0 to < 6.12unaffected
  • 6.6.67 to ≤ 6.6.*unaffected
  • 6.12.6 to ≤ 6.12.*unaffected
  • 6.13 to ≤ *unaffected

References