[PATCH 6.4 795/800] netfilter: nf_tables: do not ignore genmask when looking up chain by id

Greg Kroah-Hartman
2023-07-16T20:30:36Z

From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

commit 515ad530795c118f012539ed76d02bacfd426d89 upstream.

When adding a rule to a chain referring to its ID, if that chain had been
deleted on the same batch, the rule might end up referring to a deleted
chain.

This will lead to a WARNING like following:

[ 33.098431] ------------[ cut here ]------------
[ 33.098678] WARNING: CPU: 5 PID: 69 at net/netfilter/nf_tables_api.c:2037 nf_tables_chain_destroy+0x23d/0x260
[ 33.099217] Modules linked in:
[ 33.099388] CPU: 5 PID: 69 Comm: kworker/5:1 Not tainted 6.4.0+ #409
[ 33.099726] Workqueue: events nf_tables_trans_destroy_work
[ 33.100018] RIP: 0010:nf_tables_chain_destroy+0x23d/0x260
[ 33.100306] Code: 8b 7c 24 68 e8 64 9c ed fe 4c 89 e7 e8 5c 9c ed fe 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7 c3 cc cc cc cc <0f> 0b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7
[ 33.101271] RSP: 0018:ffffc900004ffc48 EFLAGS: 00010202
[ 33.101546] RAX: 0000000000000001 RBX: ffff888006fc0a28 RCX: 0000000000000000
[ 33.101920] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 33.102649] RBP: ffffc900004ffc78 R08: 0000000000000000 R09: 0000000000000000
[ 33.103018] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880135ef500
[ 33.103385] R13: 0000000000000000 R14: dead000000000122 R15: ffff888006fc0a10
[ 33.103762] FS: 0000000000000000(0000) GS:ffff888024c80000(0000) knlGS:0000000000000000
[ 33.104184] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 33.104493] CR2: 00007fe863b56a50 CR3: 00000000124b0001 CR4: 0000000000770ee0
[ 33.104872] PKRU: 55555554
[ 33.104999] Call Trace:
[ 33.105113] <TASK>
[ 33.105214] ? show_regs+0x72/0x90
[ 33.105371] ? __warn+0xa5/0x210
[ 33.105520] ? nf_tables_chain_destroy+0x23d/0x260
[ 33.105732] ? report_bug+0x1f2/0x200
[ 33.105902] ? handle_bug+0x46/0x90
[ 33.106546] ? exc_invalid_op+0x19/0x50
[ 33.106762] ? asm_exc_invalid_op+0x1b/0x20
[ 33.106995] ? nf_tables_chain_destroy+0x23d/0x260
[ 33.107249] ? nf_tables_chain_destroy+0x30/0x260
[ 33.107506] nf_tables_trans_destroy_work+0x669/0x680
[ 33.107782] ? mark_held_locks+0x28/0xa0
[ 33.107996] ? __pfx_nf_tables_trans_destroy_work+0x10/0x10
[ 33.108294] ? _raw_spin_unlock_irq+0x28/0x70
[ 33.108538] process_one_work+0x68c/0xb70
[ 33.108755] ? lock_acquire+0x17f/0x420
[ 33.108977] ? __pfx_process_one_work+0x10/0x10
[ 33.109218] ? do_raw_spin_lock+0x128/0x1d0
[ 33.109435] ? _raw_spin_lock_irq+0x71/0x80
[ 33.109634] worker_thread+0x2bd/0x700
[ 33.109817] ? __pfx_worker_thread+0x10/0x10
[ 33.110254] kthread+0x18b/0x1d0
[ 33.110410] ? __pfx_kthread+0x10/0x10
[ 33.110581] ret_from_fork+0x29/0x50
[ 33.110757] </TASK>
[ 33.110866] irq event stamp: 1651
[ 33.111017] hardirqs last enabled at (1659): [<ffffffffa206a209>] __up_console_sem+0x79/0xa0
[ 33.111379] hardirqs last disabled at (1666): [<ffffffffa206a1ee>] __up_console_sem+0x5e/0xa0
[ 33.111740] softirqs last enabled at (1616): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0
[ 33.112094] softirqs last disabled at (1367): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0
[ 33.112453] ---[ end trace 0000000000000000 ]---

This is due to the nft_chain_lookup_byid ignoring the genmask. After this
change, adding the new rule will fail as it will not find the chain.

Fixes: 837830a4b439 ("netfilter: nf_tables: add NFTA_RULE_CHAIN_ID attribute")
Cc: stable@vger.kernel.org
Reported-by: Mingi Cho of Theori working with ZDI
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netfilter/nf_tables_api.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2693,7 +2693,7 @@ err_hooks:

static struct nft_chain *nft_chain_lookup_byid(const struct net *net,
const struct nft_table *table,
- const struct nlattr *nla)
+ const struct nlattr *nla, u8 genmask)
{
struct nftables_pernet *nft_net = nft_pernet(net);
u32 id = ntohl(nla_get_be32(nla));
@@ -2704,7 +2704,8 @@ static struct nft_chain *nft_chain_looku

if (trans->msg_type == NFT_MSG_NEWCHAIN &&
chain->table == table &&
- id == nft_trans_chain_id(trans))
+ id == nft_trans_chain_id(trans) &&
+ nft_active_genmask(chain, genmask))
return chain;
}
return ERR_PTR(-ENOENT);
@@ -3808,7 +3809,8 @@ static int nf_tables_newrule(struct sk_b
return -EOPNOTSUPP;

} else if (nla[NFTA_RULE_CHAIN_ID]) {
- chain = nft_chain_lookup_byid(net, table, nla[NFTA_RULE_CHAIN_ID]);
+ chain = nft_chain_lookup_byid(net, table, nla[NFTA_RULE_CHAIN_ID],
+ genmask);
if (IS_ERR(chain)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN_ID]);
return PTR_ERR(chain);
@@ -10467,7 +10469,8 @@ static int nft_verdict_init(const struct
genmask);
} else if (tb[NFTA_VERDICT_CHAIN_ID]) {
chain = nft_chain_lookup_byid(ctx->net, ctx->table,
- tb[NFTA_VERDICT_CHAIN_ID]);
+ tb[NFTA_VERDICT_CHAIN_ID],
+ genmask);
if (IS_ERR(chain))
return PTR_ERR(chain);
} else {