netfilter: xtables: change targets to return error code

Part of the transition of done by this semantic patch:
// <smpl>
@ rule1 @
struct xt_target ops;
identifier check;
@@
 ops.checkentry = check;

@@
identifier rule1.check;
@@
 check(...) { <...
-return true;
+return 0;
 ...> }

@@
identifier rule1.check;
@@
 check(...) { <...
-return false;
+return -EINVAL;
 ...> }
// </smpl>

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

net/netfilter/x_tables.c

@@ -528,6 +528,8 @@ EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
 int xt_check_target(struct xt_tgchk_param *par,
 		    unsigned int size, u_int8_t proto, bool inv_proto)
 {
+	int ret;
+
 	if (XT_ALIGN(par->target->targetsize) != size) {
 		pr_err("%s_tables: %s.%u target: invalid size "
 		       "%u (kernel) != (user) %u\n",
@@ -559,8 +561,14 @@ int xt_check_target(struct xt_tgchk_param *par,
 		       par->target->proto);
 		return -EINVAL;
 	}
-	if (par->target->checkentry != NULL && !par->target->checkentry(par))
-		return -EINVAL;
+	if (par->target->checkentry != NULL) {
+		ret = par->target->checkentry(par);
+		if (ret < 0)
+			return ret;
+		else if (ret > 0)
+			/* Flag up potential errors. */
+			return -EIO;
+	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xt_check_target);

net/netfilter/xt_CONNSECMARK.c

@@ -92,7 +92,7 @@ static int connsecmark_tg_check(const struct xt_tgchk_param *par)
 	    strcmp(par->table, "security") != 0) {
 		pr_info("target only valid in the \'mangle\' "
 			"or \'security\' tables, not \'%s\'.\n", par->table);
-		return false;
+		return -EINVAL;
 	}
 
 	switch (info->mode) {
@@ -108,9 +108,9 @@ static int connsecmark_tg_check(const struct xt_tgchk_param *par)
 	if (nf_ct_l3proto_try_module_get(par->family) < 0) {
 		pr_info("cannot load conntrack support for proto=%u\n",
 			par->family);
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static void connsecmark_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_CT.c

@@ -62,7 +62,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par)
 	u8 proto;
 
 	if (info->flags & ~XT_CT_NOTRACK)
-		return false;
+		return -EINVAL;
 
 	if (info->flags & XT_CT_NOTRACK) {
 		ct = &nf_conntrack_untracked;
@@ -108,14 +108,14 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par)
 	__set_bit(IPS_CONFIRMED_BIT, &ct->status);
 out:
 	info->ct = ct;
-	return true;
+	return 0;
 
 err3:
 	nf_conntrack_free(ct);
 err2:
 	nf_ct_l3proto_module_put(par->family);
 err1:
-	return false;
+	return -EINVAL;
 }
 
 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_DSCP.c

@@ -66,9 +66,9 @@ 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 false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static unsigned int

net/netfilter/xt_HL.c

@@ -110,8 +110,8 @@ static int ttl_tg_check(const struct xt_tgchk_param *par)
 		return false;
 	}
 	if (info->mode != IPT_TTL_SET && info->ttl == 0)
-		return false;
-	return true;
+		return -EINVAL;
+	return 0;
 }
 
 static int hl_tg6_check(const struct xt_tgchk_param *par)
@@ -120,14 +120,14 @@ static int hl_tg6_check(const struct xt_tgchk_param *par)
 
 	if (info->mode > IP6T_HL_MAXMODE) {
 		pr_info("invalid or unknown mode %u\n", info->mode);
-		return false;
+		return -EINVAL;
 	}
 	if (info->mode != IP6T_HL_SET && info->hop_limit == 0) {
 		pr_info("increment/decrement does not "
 			"make sense with value 0\n");
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_target hl_tg_reg[] __read_mostly = {

net/netfilter/xt_LED.c

@@ -88,12 +88,12 @@ static int led_tg_check(const struct xt_tgchk_param *par)
 
 	if (ledinfo->id[0] == '\0') {
 		pr_info("No 'id' parameter given.\n");
-		return false;
+		return -EINVAL;
 	}
 
 	ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
 	if (!ledinternal)
-		return false;
+		return -EINVAL;
 
 	ledinternal->netfilter_led_trigger.name = ledinfo->id;
 
@@ -111,13 +111,11 @@ static int led_tg_check(const struct xt_tgchk_param *par)
 			    (unsigned long)ledinfo);
 
 	ledinfo->internal_data = ledinternal;
-
-	return true;
+	return 0;
 
 exit_alloc:
 	kfree(ledinternal);
-
-	return false;
+	return -EINVAL;
 }
 
 static void led_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_NFLOG.c

@@ -42,10 +42,10 @@ static int nflog_tg_check(const struct xt_tgchk_param *par)
 	const struct xt_nflog_info *info = par->targinfo;
 
 	if (info->flags & ~XT_NFLOG_MASK)
-		return false;
+		return -EINVAL;
 	if (info->prefix[sizeof(info->prefix) - 1] != '\0')
-		return false;
-	return true;
+		return -EINVAL;
+	return 0;
 }
 
 static struct xt_target nflog_tg_reg __read_mostly = {

net/netfilter/xt_NFQUEUE.c

@@ -92,15 +92,15 @@ static int nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
 	}
 	if (info->queues_total == 0) {
 		pr_err("NFQUEUE: number of total queues is 0\n");
-		return false;
+		return -EINVAL;
 	}
 	maxid = info->queues_total - 1 + info->queuenum;
 	if (maxid > 0xffff) {
 		pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 		       info->queues_total, maxid);
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_target nfqueue_tg_reg[] __read_mostly = {

net/netfilter/xt_RATEEST.c

@@ -109,10 +109,10 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 		    (info->interval != est->params.interval ||
 		     info->ewma_log != est->params.ewma_log)) {
 			xt_rateest_put(est);
-			return false;
+			return -EINVAL;
 		}
 		info->est = est;
-		return true;
+		return 0;
 	}
 
 	est = kzalloc(sizeof(*est), GFP_KERNEL);
@@ -136,13 +136,12 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
 
 	info->est = est;
 	xt_rateest_hash_insert(est);
-
-	return true;
+	return 0;
 
 err2:
 	kfree(est);
 err1:
-	return false;
+	return -EINVAL;
 }
 
 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_SECMARK.c

@@ -88,29 +88,29 @@ static int secmark_tg_check(const struct xt_tgchk_param *par)
 	    strcmp(par->table, "security") != 0) {
 		pr_info("target only valid in the \'mangle\' "
 			"or \'security\' tables, not \'%s\'.\n", par->table);
-		return false;
+		return -EINVAL;
 	}
 
 	if (mode && mode != info->mode) {
 		pr_info("mode already set to %hu cannot mix with "
 			"rules for mode %hu\n", mode, info->mode);
-		return false;
+		return -EINVAL;
 	}
 
 	switch (info->mode) {
 	case SECMARK_MODE_SEL:
 		if (!checkentry_selinux(info))
-			return false;
+			return -EINVAL;
 		break;
 
 	default:
 		pr_info("invalid mode: %hu\n", info->mode);
-		return false;
+		return -EINVAL;
 	}
 
 	if (!mode)
 		mode = info->mode;
-	return true;
+	return 0;
 }
 
 static void secmark_tg_destroy(const struct xt_tgdtor_param *par)

net/netfilter/xt_TCPMSS.c

@@ -246,13 +246,13 @@ static int tcpmss_tg4_check(const struct xt_tgchk_param *par)
 			   (1 << NF_INET_POST_ROUTING))) != 0) {
 		pr_info("path-MTU clamping only supported in "
 			"FORWARD, OUTPUT and POSTROUTING hooks\n");
-		return false;
+		return -EINVAL;
 	}
 	xt_ematch_foreach(ematch, e)
 		if (find_syn_match(ematch))
-			return true;
+			return 0;
 	pr_info("Only works on TCP SYN packets\n");
-	return false;
+	return -EINVAL;
 }
 
 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
@@ -268,13 +268,13 @@ static int tcpmss_tg6_check(const struct xt_tgchk_param *par)
 			   (1 << NF_INET_POST_ROUTING))) != 0) {
 		pr_info("path-MTU clamping only supported in "
 			"FORWARD, OUTPUT and POSTROUTING hooks\n");
-		return false;
+		return -EINVAL;
 	}
 	xt_ematch_foreach(ematch, e)
 		if (find_syn_match(ematch))
-			return true;
+			return 0;
 	pr_info("Only works on TCP SYN packets\n");
-	return false;
+	return -EINVAL;
 }
 #endif
 

net/netfilter/xt_TPROXY.c

@@ -65,11 +65,11 @@ static int tproxy_tg_check(const struct xt_tgchk_param *par)
 
 	if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
 	    && !(i->invflags & IPT_INV_PROTO))
-		return true;
+		return 0;
 
 	pr_info("Can be used only in combination with "
 		"either -p tcp or -p udp\n");
-	return false;
+	return -EINVAL;
 }
 
 static struct xt_target tproxy_tg_reg __read_mostly = {