From: Pablo Neira Ayuso pablo@netfilter.org
commit f9a43007d3f7ba76d5e7f9421094f00f2ef202f8 upstream.
__nft_release_hooks() is called from pre_netns exit path which unregisters the hooks, then the NETDEV_UNREGISTER event is triggered which unregisters the hooks again.
[ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270 [...] [ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27 [ 565.253682] Workqueue: netns cleanup_net [ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270 [...] [ 565.297120] Call Trace: [ 565.300900] <TASK> [ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables] [ 565.308518] raw_notifier_call_chain+0x63/0x80 [ 565.312386] unregister_netdevice_many+0x54f/0xb50
Unregister and destroy netdev hook from netns pre_exit via kfree_rcu so the NETDEV_UNREGISTER path see unregistered hooks.
Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netfilter/nf_tables_api.c | 54 +++++++++++++++++++++++++++++++----------- 1 file changed, 41 insertions(+), 13 deletions(-)
--- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -222,12 +222,18 @@ err_register: }
static void nft_netdev_unregister_hooks(struct net *net, - struct list_head *hook_list) + struct list_head *hook_list, + bool release_netdev) { - struct nft_hook *hook; + struct nft_hook *hook, *next;
- list_for_each_entry(hook, hook_list, list) + list_for_each_entry_safe(hook, next, hook_list, list) { nf_unregister_net_hook(net, &hook->ops); + if (release_netdev) { + list_del(&hook->list); + kfree_rcu(hook, rcu); + } + } }
static int nf_tables_register_hook(struct net *net, @@ -253,9 +259,10 @@ static int nf_tables_register_hook(struc return nf_register_net_hook(net, &basechain->ops); }
-static void nf_tables_unregister_hook(struct net *net, - const struct nft_table *table, - struct nft_chain *chain) +static void __nf_tables_unregister_hook(struct net *net, + const struct nft_table *table, + struct nft_chain *chain, + bool release_netdev) { struct nft_base_chain *basechain; const struct nf_hook_ops *ops; @@ -270,11 +277,19 @@ static void nf_tables_unregister_hook(st return basechain->type->ops_unregister(net, ops);
if (nft_base_chain_netdev(table->family, basechain->ops.hooknum)) - nft_netdev_unregister_hooks(net, &basechain->hook_list); + nft_netdev_unregister_hooks(net, &basechain->hook_list, + release_netdev); else nf_unregister_net_hook(net, &basechain->ops); }
+static void nf_tables_unregister_hook(struct net *net, + const struct nft_table *table, + struct nft_chain *chain) +{ + return __nf_tables_unregister_hook(net, table, chain, false); +} + static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *trans) { struct nftables_pernet *nft_net = nft_pernet(net); @@ -7301,13 +7316,25 @@ static void nft_unregister_flowtable_hoo FLOW_BLOCK_UNBIND); }
-static void nft_unregister_flowtable_net_hooks(struct net *net, - struct list_head *hook_list) +static void __nft_unregister_flowtable_net_hooks(struct net *net, + struct list_head *hook_list, + bool release_netdev) { - struct nft_hook *hook; + struct nft_hook *hook, *next;
- list_for_each_entry(hook, hook_list, list) + list_for_each_entry_safe(hook, next, hook_list, list) { nf_unregister_net_hook(net, &hook->ops); + if (release_netdev) { + list_del(&hook->list); + kfree_rcu(hook); + } + } +} + +static void nft_unregister_flowtable_net_hooks(struct net *net, + struct list_head *hook_list) +{ + __nft_unregister_flowtable_net_hooks(net, hook_list, false); }
static int nft_register_flowtable_net_hooks(struct net *net, @@ -9751,9 +9778,10 @@ static void __nft_release_hook(struct ne struct nft_chain *chain;
list_for_each_entry(chain, &table->chains, list) - nf_tables_unregister_hook(net, table, chain); + __nf_tables_unregister_hook(net, table, chain, true); list_for_each_entry(flowtable, &table->flowtables, list) - nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list); + __nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list, + true); }
static void __nft_release_hooks(struct net *net)