From: Shigeru Yoshida <syoshida@xxxxxxxxxx>
syzbot reported a warning like below [1]:
WARNING: CPU: 3 PID: 9 at net/netfilter/nf_tables_api.c:10096 nf_tables_exit_net+0x71c/0x840
Modules linked in:
CPU: 2 PID: 9 Comm: kworker/u8:0 Tainted: G W 6.1.0-rc3-00072-g8e5423e991e8 #47
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:nf_tables_exit_net+0x71c/0x840
...
Call Trace:
<TASK>
? __nft_release_table+0xfc0/0xfc0
ops_exit_list+0xb5/0x180
cleanup_net+0x506/0xb10
? unregister_pernet_device+0x80/0x80
process_one_work+0xa38/0x1730
? pwq_dec_nr_in_flight+0x2b0/0x2b0
? rwlock_bug.part.0+0x90/0x90
? _raw_spin_lock_irq+0x46/0x50
worker_thread+0x67e/0x10e0
? process_one_work+0x1730/0x1730
kthread+0x2e5/0x3a0
? kthread_complete_and_exit+0x40/0x40
ret_from_fork+0x1f/0x30
</TASK>
In nf_tables_exit_net(), there is a case where nft_net->commit_list is
empty but nft_net->module_list is not empty. Such a case occurs with
the following scenario:
1. nfnetlink_rcv_batch() is called
2. nf_tables_newset() returns -EAGAIN and NFNL_BATCH_FAILURE bit is
set to status
3. nf_tables_abort() is called with NFNL_ABORT_AUTOLOAD
(nft_net->commit_list is released, but nft_net->module_list is not
because of NFNL_ABORT_AUTOLOAD flag)
4. Jump to replay label
5. netlink_skb_clone() fails and returns from the function (this is
caused by fault injection in the reproducer of syzbot)
This patch fixes this issue by calling __nf_tables_abort() when
nft_net->module_list is not empty in nf_tables_exit_net().
Fixes: eb014de4fd41 ("netfilter: nf_tables: autoload modules from the abort path")
Link: https://syzkaller.appspot.com/bug?id=802aba2422de4218ad0c01b46c9525cc9d4e4aa3 [1]
Reported-by: syzbot+178efee9e2d7f87f5103@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 76bd4d03dbda..e7152d599d73 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -10090,7 +10090,8 @@ static void __net_exit nf_tables_exit_net(struct net *net)
struct nftables_pernet *nft_net = nft_pernet(net);
mutex_lock(&nft_net->commit_mutex);
- if (!list_empty(&nft_net->commit_list))
+ if (!list_empty(&nft_net->commit_list) ||
+ !list_empty(&nft_net->module_list))
__nf_tables_abort(net, NFNL_ABORT_NONE);
__nft_release_tables(net);
mutex_unlock(&nft_net->commit_mutex);
--
2.30.2
