netfilter: xtables: slightly better error reporting

When extended status codes are available, such as ENOMEM on failed
allocations, or subsequent functions (e.g. nf_ct_get_l3proto), passing
them up to userspace seems like a good idea compared to just always
EINVAL.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

net/ipv4/netfilter/ipt_CLUSTERIP.c

@@ -351,8 +351,8 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
 {
 	struct ipt_clusterip_tgt_info *cipinfo = par->targinfo;
 	const struct ipt_entry *e = par->entryinfo;
-
 	struct clusterip_config *config;
+	int ret;
 
 	if (cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP &&
 	    cipinfo->hash_mode != CLUSTERIP_HASHMODE_SIP_SPT &&
@@ -387,25 +387,26 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
 			if (!dev) {
 				pr_info("no such interface %s\n",
 					e->ip.iniface);
-				return -EINVAL;
+				return -ENOENT;
 			}
 
 			config = clusterip_config_init(cipinfo,
 							e->ip.dst.s_addr, dev);
 			if (!config) {
 				pr_info("cannot allocate config\n");
 				dev_put(dev);
-				return -EINVAL;
+				return -ENOMEM;
 			}
 			dev_mc_add(config->dev,config->clustermac, ETH_ALEN, 0);
 		}
 	}
 	cipinfo->config = config;
 
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 
 	return 0;

net/netfilter/xt_CONNSECMARK.c

@@ -87,6 +87,7 @@ connsecmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
 static int connsecmark_tg_check(const struct xt_tgchk_param *par)
 {
 	const struct xt_connsecmark_target_info *info = par->targinfo;
+	int ret;
 
 	if (strcmp(par->table, "mangle") != 0 &&
 	    strcmp(par->table, "security") != 0) {
@@ -102,13 +103,14 @@ static int connsecmark_tg_check(const struct xt_tgchk_param *par)
 
 	default:
 		pr_info("invalid mode: %hu\n", info->mode);
-		return false;
+		return -EINVAL;
 	}
 
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 	return 0;
 }

net/netfilter/xt_CT.c

@@ -59,6 +59,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par)
 	struct nf_conntrack_tuple t;
 	struct nf_conn_help *help;
 	struct nf_conn *ct;
+	int ret = 0;
 	u8 proto;
 
 	if (info->flags & ~XT_CT_NOTRACK)
@@ -75,28 +76,34 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par)
 		goto err1;
 #endif
 
-	if (nf_ct_l3proto_try_module_get(par->family) < 0)
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0)
 		goto err1;
 
 	memset(&t, 0, sizeof(t));
 	ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
+	ret = PTR_ERR(ct);
 	if (IS_ERR(ct))
 		goto err2;
 
+	ret = 0;
 	if ((info->ct_events || info->exp_events) &&
 	    !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
 				  GFP_KERNEL))
 		goto err3;
 
 	if (info->helper[0]) {
+		ret = -ENOENT;
 		proto = xt_ct_find_proto(par);
 		if (!proto)
 			goto err3;
 
+		ret = -ENOMEM;
 		help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
 		if (help == NULL)
 			goto err3;
 
+		ret = -ENOENT;
 		help->helper = nf_conntrack_helper_try_module_get(info->helper,
 								  par->family,
 								  proto);
@@ -115,7 +122,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par)
 err2:
 	nf_ct_l3proto_module_put(par->family);
 err1:
-	return -EINVAL;
+	return ret;
 }
 
 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_DSCP.c

@@ -66,7 +66,7 @@ static int dscp_tg_check(const struct xt_tgchk_param *par)
 
 	if (info->dscp > XT_DSCP_MAX) {
 		pr_info("dscp %x out of range\n", info->dscp);
-		return -EINVAL;
+		return -EDOM;
 	}
 	return 0;
 }

net/netfilter/xt_HL.c

@@ -107,7 +107,7 @@ static int ttl_tg_check(const struct xt_tgchk_param *par)
 
 	if (info->mode > IPT_TTL_MAXMODE) {
 		pr_info("TTL: invalid or unknown mode %u\n", info->mode);
-		return false;
+		return -EINVAL;
 	}
 	if (info->mode != IPT_TTL_SET && info->ttl == 0)
 		return -EINVAL;

net/netfilter/xt_LED.c

@@ -93,7 +93,7 @@ static int led_tg_check(const struct xt_tgchk_param *par)
 
 	ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
 	if (!ledinternal)
-		return -EINVAL;
+		return -ENOMEM;
 
 	ledinternal->netfilter_led_trigger.name = ledinfo->id;
 
@@ -115,7 +115,7 @@ static int led_tg_check(const struct xt_tgchk_param *par)
 
 exit_alloc:
 	kfree(ledinternal);
-	return -EINVAL;
+	return err;
 }
 
 static void led_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_NFQUEUE.c

@@ -98,7 +98,7 @@ static int nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
 	if (maxid > 0xffff) {
 		pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 		       info->queues_total, maxid);
-		return -EINVAL;
+		return -ERANGE;
 	}
 	return 0;
 }

net/netfilter/xt_RATEEST.c

@@ -93,6 +93,7 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 		struct nlattr		opt;
 		struct gnet_estimator	est;
 	} cfg;
+	int ret;
 
 	if (unlikely(!rnd_inited)) {
 		get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
@@ -115,6 +116,7 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 		return 0;
 	}
 
+	ret = -ENOMEM;
 	est = kzalloc(sizeof(*est), GFP_KERNEL);
 	if (!est)
 		goto err1;
@@ -130,8 +132,9 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 	cfg.est.interval	= info->interval;
 	cfg.est.ewma_log	= info->ewma_log;
 
-	if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock,
-			      &cfg.opt) < 0)
+	ret = gen_new_estimator(&est->bstats, &est->rstats,
+				&est->lock, &cfg.opt);
+	if (ret < 0)
 		goto err2;
 
 	info->est = est;
@@ -141,7 +144,7 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 err2:
 	kfree(est);
 err1:
-	return -EINVAL;
+	return ret;
 }
 
 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_SECMARK.c

@@ -50,7 +50,7 @@ secmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
 	return XT_CONTINUE;
 }
 
-static bool checkentry_selinux(struct xt_secmark_target_info *info)
+static int checkentry_selinux(struct xt_secmark_target_info *info)
 {
 	int err;
 	struct xt_secmark_target_selinux_info *sel = &info->u.sel;
@@ -62,27 +62,28 @@ static bool checkentry_selinux(struct xt_secmark_target_info *info)
 		if (err == -EINVAL)
 			pr_info("invalid SELinux context \'%s\'\n",
 				sel->selctx);
-		return false;
+		return err;
 	}
 
 	if (!sel->selsid) {
 		pr_info("unable to map SELinux context \'%s\'\n", sel->selctx);
-		return false;
+		return -ENOENT;
 	}
 
 	err = selinux_secmark_relabel_packet_permission(sel->selsid);
 	if (err) {
 		pr_info("unable to obtain relabeling permission\n");
-		return false;
+		return err;
 	}
 
 	selinux_secmark_refcount_inc();
-	return true;
+	return 0;
 }
 
 static int secmark_tg_check(const struct xt_tgchk_param *par)
 {
 	struct xt_secmark_target_info *info = par->targinfo;
+	int err;
 
 	if (strcmp(par->table, "mangle") != 0 &&
 	    strcmp(par->table, "security") != 0) {
@@ -99,8 +100,9 @@ static int secmark_tg_check(const struct xt_tgchk_param *par)
 
 	switch (info->mode) {
 	case SECMARK_MODE_SEL:
-		if (!checkentry_selinux(info))
-			return -EINVAL;
+		err = checkentry_selinux(info);
+		if (err <= 0)
+			return err;
 		break;
 
 	default:

net/netfilter/xt_cluster.c

@@ -145,7 +145,7 @@ static int xt_cluster_mt_checkentry(const struct xt_mtchk_param *par)
 	if (info->node_mask >= (1ULL << info->total_nodes)) {
 		pr_info("this node mask cannot be "
 			"higher than the total number of nodes\n");
-		return -EINVAL;
+		return -EDOM;
 	}
 	return 0;
 }

net/netfilter/xt_connbytes.c

@@ -96,6 +96,7 @@ connbytes_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 static int connbytes_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_connbytes_info *sinfo = par->matchinfo;
+	int ret;
 
 	if (sinfo->what != XT_CONNBYTES_PKTS &&
 	    sinfo->what != XT_CONNBYTES_BYTES &&
@@ -107,10 +108,11 @@ static int connbytes_mt_check(const struct xt_mtchk_param *par)
 	    sinfo->direction != XT_CONNBYTES_DIR_BOTH)
 		return -EINVAL;
 
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 
 	return 0;

net/netfilter/xt_connlimit.c

@@ -220,22 +220,24 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
 {
 	struct xt_connlimit_info *info = par->matchinfo;
 	unsigned int i;
+	int ret;
 
 	if (unlikely(!connlimit_rnd_inited)) {
 		get_random_bytes(&connlimit_rnd, sizeof(connlimit_rnd));
 		connlimit_rnd_inited = true;
 	}
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for "
 			"address family %u\n", par->family);
-		return -EINVAL;
+		return ret;
 	}
 
 	/* init private data */
 	info->data = kmalloc(sizeof(struct xt_connlimit_data), GFP_KERNEL);
 	if (info->data == NULL) {
 		nf_ct_l3proto_module_put(par->family);
-		return -EINVAL;
+		return -ENOMEM;
 	}
 
 	spin_lock_init(&info->data->lock);

net/netfilter/xt_connmark.c

@@ -76,10 +76,13 @@ connmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
 
 static int connmark_tg_check(const struct xt_tgchk_param *par)
 {
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	int ret;
+
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 	return 0;
 }
@@ -105,10 +108,13 @@ connmark_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 
 static int connmark_mt_check(const struct xt_mtchk_param *par)
 {
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	int ret;
+
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 	return 0;
 }

net/netfilter/xt_conntrack.c

@@ -208,10 +208,13 @@ conntrack_mt_v2(const struct sk_buff *skb, const struct xt_match_param *par)
 
 static int conntrack_mt_check(const struct xt_mtchk_param *par)
 {
-	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+	int ret;
+
+	ret = nf_ct_l3proto_try_module_get(par->family);
+	if (ret < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return -EINVAL;
+		return ret;
 	}
 	return 0;
 }

net/netfilter/xt_dscp.c

@@ -48,7 +48,7 @@ static int dscp_mt_check(const struct xt_mtchk_param *par)
 
 	if (info->dscp > XT_DSCP_MAX) {
 		pr_info("dscp %x out of range\n", info->dscp);
-		return -EINVAL;
+		return -EDOM;
 	}
 
 	return 0;