diff --git a/lib/chkname.c b/lib/chkname.c
index cbfbff51..1c596349 100644
--- a/lib/chkname.c
+++ b/lib/chkname.c
@@ -80,7 +80,7 @@ bool is_valid_user_name (const char *name)
 	 * User names length are limited by the kernel
 	 */
 	maxlen = sysconf(_SC_LOGIN_NAME_MAX);
-	if (strlen(name) > maxlen)
+	if (strlen(name) >= maxlen)
 		return false;
 
 	return is_valid_name (name);
diff --git a/tests/unit/test_chkname.c b/tests/unit/test_chkname.c
index af982940..e0f9f84b 100644
--- a/tests/unit/test_chkname.c
+++ b/tests/unit/test_chkname.c
@@ -134,15 +134,15 @@ test_is_valid_user_name_long(void **state)
 	char    *name;
 
 	max = sysconf(_SC_LOGIN_NAME_MAX);
-	name = MALLOC(max + 2, char);
+	name = MALLOC(max + 1, char);
 	assert_true(name != NULL);
 
-	memset(name, '_', max + 1);
-
-	name[max + 1] = '\0';
-	assert_true(false == is_valid_user_name(name));
+	memset(name, '_', max);
 
 	name[max] = '\0';
+	assert_true(false == is_valid_user_name(name));
+
+	name[max - 1] = '\0';
 	assert_true(is_valid_user_name(name));
 
 	free(name);