netfilter: xtables: change xt_match.checkentry return type

Restore function signatures from bool to int so that we can report
memory allocation failures or similar using -ENOMEM rather than
always having to pass -EINVAL back.

This semantic patch may not be too precise (checking for functions
that use xt_mtchk_param rather than functions referenced by
xt_match.checkentry), but reviewed, it produced the intended result.

// <smpl>
@@
type bool;
identifier check, par;
@@
-bool check
+int check
 (struct xt_mtchk_param *par) { ... }
// </smpl>

Signed-off-by: Jan Engelhardt <[email protected]>

net/ipv4/netfilter/ip_tables.c

@@ -2176,7 +2176,7 @@ icmp_match(const struct sk_buff *skb, const struct xt_match_param *par)
 				    !!(icmpinfo->invflags&IPT_ICMP_INV));
 }
 
-static bool icmp_checkentry(const struct xt_mtchk_param *par)
+static int icmp_checkentry(const struct xt_mtchk_param *par)
 {
 	const struct ipt_icmp *icmpinfo = par->matchinfo;
 

net/ipv4/netfilter/ipt_addrtype.c

@@ -70,7 +70,7 @@ addrtype_mt_v1(const struct sk_buff *skb, const struct xt_match_param *par)
 	return ret;
 }
 
-static bool addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
+static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
 {
 	struct ipt_addrtype_info_v1 *info = par->matchinfo;
 

net/ipv4/netfilter/ipt_ah.c

@@ -55,7 +55,7 @@ static bool ah_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 			 !!(ahinfo->invflags & IPT_AH_INV_SPI));
 }
 
-static bool ah_mt_check(const struct xt_mtchk_param *par)
+static int ah_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct ipt_ah *ahinfo = par->matchinfo;
 

net/ipv4/netfilter/ipt_ecn.c

@@ -85,7 +85,7 @@ static bool ecn_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	return true;
 }
 
-static bool ecn_mt_check(const struct xt_mtchk_param *par)
+static int ecn_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct ipt_ecn_info *info = par->matchinfo;
 	const struct ipt_ip *ip = par->entryinfo;