Smack: don't show empty rules when /smack/load or /smack/load2 is read

This patch removes empty rules (i.e. with access set to '-') from the
rule list presented to user space.

Smack by design never removes labels nor rules from its lists. Access
for a rule may be set to '-' to effectively disable it. Such rules would
show up in the listing generated when /smack/load or /smack/load2 is
read. This may cause clutter if many rules were disabled.

As a rule with access set to '-' is equivalent to no rule at all, they
may be safely hidden from the listing.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Rafal Krypa <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>

security/smack/smackfs.c

@@ -518,6 +518,9 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	if (strlen(srp->smk_subject) >= max || strlen(srp->smk_object) >= max)
 		return;
 
+	if (srp->smk_access == 0)
+		return;
+
 	seq_printf(s, "%s %s", srp->smk_subject, srp->smk_object);
 
 	seq_putc(s, ' ');
@@ -532,8 +535,6 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 		seq_putc(s, 'a');
 	if (srp->smk_access & MAY_TRANSMUTE)
 		seq_putc(s, 't');
-	if (srp->smk_access == 0)
-		seq_putc(s, '-');
 
 	seq_putc(s, '\n');
 }