netfilter: xt_socket: enable defrag after all other checks

[ Upstream commit 542be3f ]

Originally this did not matter because defrag was enabled once per netns
and only disabled again on netns dismantle.  When this got changed I should
have adjusted checkentry to not leave defrag enabled on error.

Fixes: de8c121 ("netfilter: disable defrag once its no longer needed")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Florian Westphal

net/netfilter/xt_socket.c

@@ -168,52 +168,41 @@ static int socket_mt_enable_defrag(struct net *net, int family)
 static int socket_mt_v1_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
-	int err;
-
-	err = socket_mt_enable_defrag(par->net, par->family);
-	if (err)
-		return err;
 
 	if (info->flags & ~XT_SOCKET_FLAGS_V1) {
 		pr_info_ratelimited("unknown flags 0x%x\n",
 				    info->flags & ~XT_SOCKET_FLAGS_V1);
 		return -EINVAL;
 	}
-	return 0;
+
+	return socket_mt_enable_defrag(par->net, par->family);
 }
 
 static int socket_mt_v2_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_socket_mtinfo2 *info = (struct xt_socket_mtinfo2 *) par->matchinfo;
-	int err;
-
-	err = socket_mt_enable_defrag(par->net, par->family);
-	if (err)
-		return err;
 
 	if (info->flags & ~XT_SOCKET_FLAGS_V2) {
 		pr_info_ratelimited("unknown flags 0x%x\n",
 				    info->flags & ~XT_SOCKET_FLAGS_V2);
 		return -EINVAL;
 	}
-	return 0;
+
+	return socket_mt_enable_defrag(par->net, par->family);
 }
 
 static int socket_mt_v3_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_socket_mtinfo3 *info =
 				    (struct xt_socket_mtinfo3 *)par->matchinfo;
-	int err;
 
-	err = socket_mt_enable_defrag(par->net, par->family);
-	if (err)
-		return err;
 	if (info->flags & ~XT_SOCKET_FLAGS_V3) {
 		pr_info_ratelimited("unknown flags 0x%x\n",
 				    info->flags & ~XT_SOCKET_FLAGS_V3);
 		return -EINVAL;
 	}
-	return 0;
+
+	return socket_mt_enable_defrag(par->net, par->family);
 }
 
 static void socket_mt_destroy(const struct xt_mtdtor_param *par)