selinux: fix memory leak in policydb_init()

Since roles_init() adds some entries to the role hash table, we need to
destroy also its keys/values on error, otherwise we get a memory leak in
the error path.

Cc: <stable@vger.kernel.org>
Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
Fixes: 1da177e ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/ss/policydb.c

@@ -274,6 +274,8 @@ static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
 	return v;
 }
 
+static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap);
+
 /*
  * Initialize a policy database structure.
  */
@@ -321,8 +323,10 @@ static int policydb_init(struct policydb *p)
 out:
 	hashtab_destroy(p->filename_trans);
 	hashtab_destroy(p->range_tr);
-	for (i = 0; i < SYM_NUM; i++)
+	for (i = 0; i < SYM_NUM; i++) {
+		hashtab_map(p->symtab[i].table, destroy_f[i], NULL);
 		hashtab_destroy(p->symtab[i].table);
+	}
 	return rc;
 }