BUG(go-landlock) visible when adding non-file access rights on files

[gnoack]

When using non-file access rights on files (rather than directories),
it is possible to get go-landlock to return a BUG(go-landlock) error.

This is unintended and should be fixed.

Reported by https://www.reddit.com/user/ikmckenz/ on https://www.reddit.com/r/linuxquestions/comments/17qg6fj/give_landlock_access_to_devnull_properly/

[ikmckenz]

Example:

package main

import (
	"fmt"
	"github.com/landlock-lsm/go-landlock/landlock"
)

func main() {
	err := landlock.V3.BestEffort().RestrictPaths(
		landlock.PathAccess(0b1111111111111, "/dev/null"),
	)
	if err != nil {
		fmt.Println(err)
	}
}

Returns:
populating ruleset for "/dev/null" with access {execute,write_file,read_file,read_dir,remove_dir,remove_file,make_char,make_dir,make_reg,make_sock,make_fifo,make_block,make_sym}: landlock_add_rule: BUG(go-landlock): This should not have happened: invalid flags, or inconsistent access in the rule: invalid argument