Rule replacement routine removes an old rule then adds a new rule.
In the old rule removing routine, below steps are needed.
Allocate trans, deactivate rule and deactivate expressons of rule.
But there is no expression deactivation routine in rule replacement
routine.
test commands:
%nft add table ip filter
%nft add chain ip filter c1
%nft add chain ip filter c1
%nft add rule ip filter c1 jump c2
%nft replace rule ip filter c1 handle 3 accept
%nft flush ruleset
<jump c2> expression means immediate NFT_JUMP to chain c2.
Reference count of chain c2 is increased when the rule is added.
When rule is deleted or replaced, reference count of c2 should be
decreased. reference count decrement routine is in
the nft_immediate_deactivate().
That function is called by nft_rule_expr_deactivate().
But There is no nft_rule_expr_deactivate() in the rule replacement
routine. therefore reference count is not decreased.
That eventually makes the below message.
splat looks like:
[ 214.396453] WARNING: CPU: 1 PID: 21 at net/netfilter/nf_tables_api.c:1432 nf_tables_chain_destroy.isra.38+0x2f9/0x3a0 [nf_tables]
[ 214.398983] Modules linked in: nf_tables nfnetlink
[ 214.398983] CPU: 1 PID: 21 Comm: kworker/1:1 Not tainted 4.20.0-rc2+ #44
[ 214.398983] Workqueue: events nf_tables_trans_destroy_work [nf_tables]
[ 214.398983] RIP: 0010:nf_tables_chain_destroy.isra.38+0x2f9/0x3a0 [nf_tables]
[ 214.398983] Code: 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8e 00 00 00 48 8b 7b 58 e8 e1 2c 4e c6 48 89 df e8 d9 2c 4e c6 eb 9a <0f> 0b eb 96 0f 0b e9 7e fe ff ff e8 a7 7e 4e c6 e9 a4 fe ff ff e8
[ 214.398983] RSP: 0018:ffff8881152874e8 EFLAGS: 00010202
[ 214.398983] RAX: 0000000000000001 RBX: ffff88810ef9fc28 RCX: ffff8881152876f0
[ 214.398983] RDX: dffffc0000000000 RSI: 1ffff11022a50ede RDI: ffff88810ef9fc78
[ 214.398983] RBP: 1ffff11022a50e9d R08: 0000000080000000 R09: 0000000000000000
[ 214.398983] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff11022a50eba
[ 214.398983] R13: ffff888114446e08 R14: ffff8881152876f0 R15: ffffed1022a50ed6
[ 214.398983] FS: 0000000000000000(0000) GS:ffff888116400000(0000) knlGS:0000000000000000
[ 214.398983] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 214.398983] CR2: 00007fab9bb5f868 CR3: 000000012aa16000 CR4: 00000000001006e0
[ 214.398983] Call Trace:
[ 214.398983] ? nf_tables_table_destroy.isra.37+0x100/0x100 [nf_tables]
[ 214.398983] ? __kasan_slab_free+0x145/0x180
[ 214.398983] ? nf_tables_trans_destroy_work+0x439/0x830 [nf_tables]
[ 214.398983] ? kfree+0xdb/0x280
[ 214.398983] nf_tables_trans_destroy_work+0x5f5/0x830 [nf_tables]
[ ... ]
Fixes: bb7b40aecbf7 ("netfilter: nf_tables: bogus EBUSY in chain deletions")
Reported by: Christoph Anton Mitterer <calestyo@xxxxxxxxxxxx>
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914505
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201791
Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ddeaa1990e1e..2e61aab6ed73 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2667,21 +2667,14 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
}
if (nlh->nlmsg_flags & NLM_F_REPLACE) {
- if (!nft_is_active_next(net, old_rule)) {
- err = -ENOENT;
- goto err2;
- }
- trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE,
- old_rule);
+ trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
if (trans == NULL) {
err = -ENOMEM;
goto err2;
}
- nft_deactivate_next(net, old_rule);
- chain->use--;
-
- if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
- err = -ENOMEM;
+ err = nft_delrule(&ctx, old_rule);
+ if (err < 0) {
+ nft_trans_destroy(trans);
goto err2;
}
--
2.17.1
