commit 590025a27fe0603e855a054c4ad57d966bd8af07
author Liping Zhang <liping.zhang@spreadtrum.com> Sat Jul 16 14:27:21 2016 +0800
committer Pablo Neira Ayuso <pablo@netfilter.org> Tue Jul 19 19:52:03 2016 +0200
tree 75ef71f76d2da9d44102660d39cfa061b5e7447c
parent f4dc77713f8016d2e8a3295e1c9c53a21f296def

netfilter: nft_ct: fix unpaired nf_connlabels_get/put call

We only get nf_connlabels if the user add ct label set expr successfully,
but we will also put nf_connlabels if the user delete ct lable get expr.
This is mismathced, and will cause ct label expr cannot work properly.

Also, if we init something fail, we should put nf_connlabels back.
Otherwise, we may waste to alloc the memory that will never be used.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_ct.c

diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 7ce8fd7..d9e44ca 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -366,6 +366,7 @@
 			   const struct nlattr * const tb[])
 {
 	struct nft_ct *priv = nft_expr_priv(expr);
+	bool label_got = false;
 	unsigned int len;
 	int err;
 
@@ -384,6 +385,7 @@
 		err = nf_connlabels_get(ctx->net, (len * BITS_PER_BYTE) - 1);
 		if (err)
 			return err;
+		label_got = true;
 		break;
 #endif
 	default:
@@ -393,17 +395,28 @@
 	priv->sreg = nft_parse_register(tb[NFTA_CT_SREG]);
 	err = nft_validate_register_load(priv->sreg, len);
 	if (err < 0)
-		return err;
+		goto err1;
 
 	err = nft_ct_l3proto_try_module_get(ctx->afi->family);
 	if (err < 0)
-		return err;
+		goto err1;
 
 	return 0;
+
+err1:
+	if (label_got)
+		nf_connlabels_put(ctx->net);
+	return err;
 }
 
-static void nft_ct_destroy(const struct nft_ctx *ctx,
-			   const struct nft_expr *expr)
+static void nft_ct_get_destroy(const struct nft_ctx *ctx,
+			       const struct nft_expr *expr)
+{
+	nft_ct_l3proto_module_put(ctx->afi->family);
+}
+
+static void nft_ct_set_destroy(const struct nft_ctx *ctx,
+			       const struct nft_expr *expr)
 {
 	struct nft_ct *priv = nft_expr_priv(expr);
 
@@ -475,7 +488,7 @@
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 	.eval		= nft_ct_get_eval,
 	.init		= nft_ct_get_init,
-	.destroy	= nft_ct_destroy,
+	.destroy	= nft_ct_get_destroy,
 	.dump		= nft_ct_get_dump,
 };
 
@@ -484,7 +497,7 @@
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 	.eval		= nft_ct_set_eval,
 	.init		= nft_ct_set_init,
-	.destroy	= nft_ct_destroy,
+	.destroy	= nft_ct_set_destroy,
 	.dump		= nft_ct_set_dump,
 };