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authorPablo Neira Ayuso <pablo@netfilter.org>2022-05-30 18:24:06 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2022-05-31 23:13:10 +0200
commitf9a43007d3f7ba76d5e7f9421094f00f2ef202f8 (patch)
tree8cecca84314fa482593e52f5dadd6ce1740cbb3c /net
parent3923b1e4406680d57da7e873da77b1683035d83f (diff)
downloadlinux-f9a43007d3f7ba76d5e7f9421094f00f2ef202f8.tar.bz2
netfilter: nf_tables: double hook unregistration in netns path
__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>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_tables_api.c54
1 files changed, 41 insertions, 13 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index f77414e13de1..746be13438ef 100644
--- 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(struct net *net,
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(struct net *net,
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);
@@ -7307,13 +7322,25 @@ static void nft_unregister_flowtable_hook(struct net *net,
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,
@@ -9755,9 +9782,10 @@ static void __nft_release_hook(struct net *net, struct nft_table *table)
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)