From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit 767d1216bff82507c945e92fe719dff2083bb2f4 ]
Although hooks are released via call_rcu(), chain and rule objects are immediately released while packets are still walking over these bits.
This patch adds the .pre_exit callback which is invoked before synchronize_rcu() in the netns framework to stay safe.
Remove a comment which is not valid anymore since the core does not use synchronize_net() anymore since 8c873e219970 ("netfilter: core: free hooks with call_rcu").
Suggested-by: Florian Westphal fw@strlen.de Fixes: df05ef874b28 ("netfilter: nf_tables: release objects on netns destruction") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_api.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 9a080767667b7..8739ef135156b 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -8775,6 +8775,17 @@ int __nft_release_basechain(struct nft_ctx *ctx) } EXPORT_SYMBOL_GPL(__nft_release_basechain);
+static void __nft_release_hooks(struct net *net) +{ + struct nft_table *table; + struct nft_chain *chain; + + list_for_each_entry(table, &net->nft.tables, list) { + list_for_each_entry(chain, &table->chains, list) + nf_tables_unregister_hook(net, table, chain); + } +} + static void __nft_release_tables(struct net *net) { struct nft_flowtable *flowtable, *nf; @@ -8790,10 +8801,6 @@ static void __nft_release_tables(struct net *net)
list_for_each_entry_safe(table, nt, &net->nft.tables, list) { ctx.family = table->family; - - list_for_each_entry(chain, &table->chains, list) - nf_tables_unregister_hook(net, table, chain); - /* No packets are walking on these chains anymore. */ ctx.table = table; list_for_each_entry(chain, &table->chains, list) { ctx.chain = chain; @@ -8842,6 +8849,11 @@ static int __net_init nf_tables_init_net(struct net *net) return 0; }
+static void __net_exit nf_tables_pre_exit_net(struct net *net) +{ + __nft_release_hooks(net); +} + static void __net_exit nf_tables_exit_net(struct net *net) { mutex_lock(&net->nft.commit_mutex); @@ -8855,8 +8867,9 @@ static void __net_exit nf_tables_exit_net(struct net *net) }
static struct pernet_operations nf_tables_net_ops = { - .init = nf_tables_init_net, - .exit = nf_tables_exit_net, + .init = nf_tables_init_net, + .pre_exit = nf_tables_pre_exit_net, + .exit = nf_tables_exit_net, };
static int __init nf_tables_module_init(void)