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.
Product status
9eee6097ffb26cdd2adb988c0d378fa0d650c737 (git) before 5146c27b2780aac59876a887a5f4e793b8949862
558f503f707f481bbf40efa74a938b8021df841d (git) before 2991dc357a28b61c13ed1f7b59e9251e2b4562fb
a394c160d57f4b083bd904a22802f6fb7f5b3cea (git) before b8d8f53e1858178882b881b8c09f94ef0e83bf76
e6c32a64d61184c2bdf89442b3d31ef530afba34 (git) before b0f013bebf94fe7ae75e5a53be2f2bd1cc1841e3
bfd05c68e4c6320304e9f371ffa356b6e4b9cc53 (git) before 27f0574253f6c24c8ee4e3f0a685b75ed3a256ed
c03d278fdf35e73dd0ec543b9b556876b9d9a8dc (git) before 7cf0bd232b565d9852cb25fd094f77254773e048
c03d278fdf35e73dd0ec543b9b556876b9d9a8dc (git) before b04df3da1b5c6f6dc7cdccc37941740c078c4043
cb401e5799e0acacb405f2128097e9c4ccf82f8a (git)
6.12
Any version before 6.12
6.6.67 (semver)
6.12.6 (semver)
6.13 (original_commit_for_fix)
References
git.kernel.org/...c/5146c27b2780aac59876a887a5f4e793b8949862
git.kernel.org/...c/2991dc357a28b61c13ed1f7b59e9251e2b4562fb
git.kernel.org/...c/b8d8f53e1858178882b881b8c09f94ef0e83bf76
git.kernel.org/...c/b0f013bebf94fe7ae75e5a53be2f2bd1cc1841e3
git.kernel.org/...c/27f0574253f6c24c8ee4e3f0a685b75ed3a256ed
git.kernel.org/...c/7cf0bd232b565d9852cb25fd094f77254773e048
git.kernel.org/...c/b04df3da1b5c6f6dc7cdccc37941740c078c4043