[Jammy, OEM-5.17, OEM-6.0, OEM-6.1, Lunar 2/3] netfilter: nf_tables: skip immediate deactivate in _PREPARE_ERROR

[Thadeu Lima de Souza Cascardo]

From: Pablo Neira Ayuso <pablo at netfilter.org>

On error when building the rule, the immediate expression unbinds the
chain, hence objects can be deactivated by the transaction records.

Otherwise, it is possible to trigger the following warning:

 WARNING: CPU: 3 PID: 915 at net/netfilter/nf_tables_api.c:2013 nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]
 CPU: 3 PID: 915 Comm: chain-bind-err- Not tainted 6.1.39 #1
 RIP: 0010:nf_tables_chain_destroy+0x1f7/0x210 [nf_tables]

Fixes: 4bedf9eee016 ("netfilter: nf_tables: fix chain binding transaction logic")
Reported-by: Kevin Rich <kevinrich1337 at gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
Signed-off-by: Florian Westphal <fw at strlen.de>
(cherry picked from commit 0a771f7b266b02d262900c75f1e175c7fe76fec2)
CVE-2023-4015
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
---
 net/netfilter/nft_immediate.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index 3d76ebfe8939..785f104e83ee 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -125,15 +125,27 @@ static void nft_immediate_activate(const struct nft_ctx *ctx,
 	return nft_data_hold(&priv->data, nft_dreg_to_type(priv->dreg));
 }
 
+static void nft_immediate_chain_deactivate(const struct nft_ctx *ctx,
+					   struct nft_chain *chain,
+					   enum nft_trans_phase phase)
+{
+	struct nft_ctx chain_ctx;
+	struct nft_rule *rule;
+
+	chain_ctx = *ctx;
+	chain_ctx.chain = chain;
+
+	list_for_each_entry(rule, &chain->rules, list)
+		nft_rule_expr_deactivate(&chain_ctx, rule, phase);
+}
+
 static void nft_immediate_deactivate(const struct nft_ctx *ctx,
 				     const struct nft_expr *expr,
 				     enum nft_trans_phase phase)
 {
 	const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 	const struct nft_data *data = &priv->data;
-	struct nft_ctx chain_ctx;
 	struct nft_chain *chain;
-	struct nft_rule *rule;
 
 	if (priv->dreg == NFT_REG_VERDICT) {
 		switch (data->verdict.code) {
@@ -143,20 +155,17 @@ static void nft_immediate_deactivate(const struct nft_ctx *ctx,
 			if (!nft_chain_binding(chain))
 				break;
 
-			chain_ctx = *ctx;
-			chain_ctx.chain = chain;
-
-			list_for_each_entry(rule, &chain->rules, list)
-				nft_rule_expr_deactivate(&chain_ctx, rule, phase);
-
 			switch (phase) {
 			case NFT_TRANS_PREPARE_ERROR:
 				nf_tables_unbind_chain(ctx, chain);
-				fallthrough;
+				nft_deactivate_next(ctx->net, chain);
+				break;
 			case NFT_TRANS_PREPARE:
+				nft_immediate_chain_deactivate(ctx, chain, phase);
 				nft_deactivate_next(ctx->net, chain);
 				break;
 			default:
+				nft_immediate_chain_deactivate(ctx, chain, phase);
 				nft_chain_del(chain);
 				chain->bound = false;
 				chain->table->use--;
-- 
2.34.1