mirror of
https://gitlab.com/fabinfra/fabaccess/bffh.git
synced 2024-12-04 20:04:56 +01:00
363 lines
11 KiB
Rust
363 lines
11 KiB
Rust
//! Access control logic
|
||
//!
|
||
|
||
use std::fmt;
|
||
use std::cmp::Ordering;
|
||
use std::convert::{TryFrom, Into};
|
||
|
||
|
||
fn is_sep_char(c: char) -> bool {
|
||
c == '.'
|
||
}
|
||
|
||
#[derive(Debug, Clone, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
|
||
/// A set of privileges to a thing
|
||
pub struct PrivilegesBuf {
|
||
/// Which permission is required to know about the existance of this thing
|
||
pub disclose: PermissionBuf,
|
||
/// Which permission is required to read this thing
|
||
pub read: PermissionBuf,
|
||
/// Which permission is required to write parts of this thing
|
||
pub write: PermissionBuf,
|
||
/// Which permission is required to manage all parts of this thing
|
||
pub manage: PermissionBuf
|
||
}
|
||
|
||
#[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
|
||
#[repr(transparent)]
|
||
#[serde(transparent)]
|
||
/// An owned permission string
|
||
///
|
||
/// This is under the hood just a fancy std::String.
|
||
// TODO: What is the possible fallout from homograph attacks?
|
||
// i.e. "bffh.perm" is not the same as "bffհ.реrm" (Armenian 'հ':Հ and Cyrillic 'е':Е)
|
||
// See also https://util.unicode.org/UnicodeJsps/confusables.jsp
|
||
pub struct PermissionBuf {
|
||
inner: String,
|
||
}
|
||
impl PermissionBuf {
|
||
#[inline(always)]
|
||
/// Allocate an empty `PermissionBuf`
|
||
pub fn new() -> Self {
|
||
PermissionBuf { inner: String::new() }
|
||
}
|
||
|
||
#[inline(always)]
|
||
/// Allocate a `PermissionBuf` with the given capacity given to the internal [`String`]
|
||
pub fn with_capacity(cap: usize) -> Self {
|
||
PermissionBuf { inner: String::with_capacity(cap) }
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn as_permission(&self) -> &Permission {
|
||
self.as_ref()
|
||
}
|
||
|
||
pub fn push<P: AsRef<Permission>>(&mut self, perm: P) {
|
||
self._push(perm.as_ref())
|
||
}
|
||
|
||
pub fn _push(&mut self, perm: &Permission) {
|
||
// in general we always need a separator unless the last byte is one or the string is empty
|
||
let need_sep = self.inner.chars().rev().next().map(|c| !is_sep_char(c)).unwrap_or(false);
|
||
if need_sep {
|
||
self.inner.push('.')
|
||
}
|
||
self.inner.push_str(perm.as_str())
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub const fn from_string_unchecked(inner: String) -> Self {
|
||
Self { inner }
|
||
}
|
||
|
||
#[inline]
|
||
pub fn from_perm(perm: &Permission) -> Self {
|
||
Self { inner: perm.as_str().to_string() }
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn into_string(self) -> String {
|
||
self.inner
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn is_empty(&self) -> bool {
|
||
self.inner.is_empty()
|
||
}
|
||
}
|
||
impl AsRef<String> for PermissionBuf {
|
||
#[inline(always)]
|
||
fn as_ref(&self) -> &String {
|
||
&self.inner
|
||
}
|
||
}
|
||
impl AsRef<str> for PermissionBuf {
|
||
#[inline(always)]
|
||
fn as_ref(&self) -> &str {
|
||
&self.inner.as_str()
|
||
}
|
||
}
|
||
impl AsRef<Permission> for PermissionBuf {
|
||
#[inline]
|
||
fn as_ref(&self) -> &Permission {
|
||
Permission::new(self)
|
||
}
|
||
}
|
||
impl PartialOrd for PermissionBuf {
|
||
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
|
||
let a: &Permission = self.as_ref();
|
||
a.partial_cmp(other.as_ref())
|
||
}
|
||
}
|
||
impl fmt::Display for PermissionBuf {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
self.inner.fmt(f)
|
||
}
|
||
}
|
||
|
||
#[derive(PartialEq, Eq, Hash, Debug)]
|
||
#[repr(transparent)]
|
||
/// A borrowed permission string
|
||
///
|
||
/// Permissions have total equality and partial ordering.
|
||
/// Specifically permissions on the same path in a tree can be compared for specificity.
|
||
/// This means that ```(bffh.perm) > (bffh.perm.sub) == true```
|
||
/// but ```(bffh.perm) > (unrelated.but.more.specific.perm) == false```.
|
||
/// This allows to check if PermRule a grants Perm b by checking `a > b`.
|
||
pub struct Permission(str);
|
||
impl Permission {
|
||
#[inline(always)]
|
||
// We can't make this `const` just yet because `str` is always a fat pointer meaning we can't
|
||
// just const cast it, and `CoerceUnsized` and friends are currently unstable.
|
||
pub fn new<S: AsRef<str> + ?Sized>(s: &S) -> &Permission {
|
||
// Safe because s is a valid reference
|
||
unsafe { &*(s.as_ref() as *const str as *const Permission) }
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn as_str(&self) -> &str {
|
||
&self.0
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn iter(&self) -> std::str::Split<char> {
|
||
self.0.split('.')
|
||
}
|
||
}
|
||
|
||
impl PartialOrd for Permission {
|
||
fn partial_cmp(&self, other: &Permission) -> Option<Ordering> {
|
||
let mut i = self.iter();
|
||
let mut j = other.iter();
|
||
let (mut l, mut r);
|
||
while {
|
||
l = i.next();
|
||
r = j.next();
|
||
|
||
l.is_some() && r.is_some()
|
||
} {
|
||
if l.unwrap() != r.unwrap() {
|
||
return None;
|
||
}
|
||
}
|
||
|
||
match (l,r) {
|
||
(None, None) => Some(Ordering::Equal),
|
||
(Some(_), None) => Some(Ordering::Less),
|
||
(None, Some(_)) => Some(Ordering::Greater),
|
||
(Some(_), Some(_)) => unreachable!("Broken contract in Permission::partial_cmp: sides \
|
||
should never be both Some!"),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl AsRef<Permission> for Permission {
|
||
#[inline]
|
||
fn as_ref(&self) -> &Permission {
|
||
self
|
||
}
|
||
}
|
||
|
||
#[derive(Clone, Debug, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
|
||
#[serde(try_from = "String")]
|
||
#[serde(into = "String")]
|
||
pub enum PermRule {
|
||
/// The permission is precise,
|
||
///
|
||
/// i.e. `Base("bffh.perm")` grants bffh.perm but does not grant permission for bffh.perm.sub
|
||
Base(PermissionBuf),
|
||
/// The permissions is for the children of the node
|
||
///
|
||
/// i.e. `Children("bffh.perm")` grants bffh.perm.sub, bffh.perm.sub.two *BUT NOT* bffh.perm
|
||
/// itself.
|
||
Children(PermissionBuf),
|
||
/// The permissions is for the subtree marked by the node
|
||
///
|
||
/// i.e. `Children("bffh.perm")` grants bffh.perm.sub, bffh.perm.sub.two and also bffh.perm
|
||
/// itself.
|
||
Subtree(PermissionBuf),
|
||
// This lacks what LDAP calls "ONELEVEL": The ability to grant the exact children but not several
|
||
// levels deep, i.e. `Onelevel("bffh.perm")` grants bffh.perm.sub *BUT NOT* bffh.perm.sub.two or
|
||
// bffh.perm itself.
|
||
// I can't think of a reason to use that so I'm skipping it for now.
|
||
}
|
||
|
||
impl PermRule {
|
||
// Does this rule match that permission
|
||
pub fn match_perm<P: AsRef<Permission> + ?Sized>(&self, perm: &P) -> bool {
|
||
match self {
|
||
PermRule::Base(ref base) => base.as_permission() == perm.as_ref(),
|
||
PermRule::Children(ref parent) => parent.as_permission() > perm.as_ref() ,
|
||
PermRule::Subtree(ref parent) => parent.as_permission() >= perm.as_ref(),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl fmt::Display for PermRule {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
match self {
|
||
PermRule::Base(perm)
|
||
=> write!(f, "{}", perm),
|
||
PermRule::Children(parent)
|
||
=> write!(f,"{}.+", parent),
|
||
PermRule::Subtree(parent)
|
||
=> write!(f,"{}.*", parent),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl Into<String> for PermRule {
|
||
fn into(self) -> String {
|
||
match self {
|
||
PermRule::Base(perm) => perm.into_string(),
|
||
PermRule::Children(mut perm) => {
|
||
perm.push(Permission::new("+"));
|
||
perm.into_string()
|
||
},
|
||
PermRule::Subtree(mut perm) => {
|
||
perm.push(Permission::new("+"));
|
||
perm.into_string()
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
impl TryFrom<String> for PermRule {
|
||
type Error = &'static str;
|
||
|
||
fn try_from(mut input: String) -> std::result::Result<Self, Self::Error> {
|
||
// Check out specifically the last two chars
|
||
let len = input.len();
|
||
if len <= 2 {
|
||
Err("Input string for PermRule is too short")
|
||
} else {
|
||
match &input[len-2..len] {
|
||
".+" => {
|
||
input.truncate(len-2);
|
||
Ok(PermRule::Children(PermissionBuf::from_string_unchecked(input)))
|
||
},
|
||
".*" => {
|
||
input.truncate(len-2);
|
||
Ok(PermRule::Subtree(PermissionBuf::from_string_unchecked(input)))
|
||
},
|
||
_ => Ok(PermRule::Base(PermissionBuf::from_string_unchecked(input))),
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
#[test]
|
||
fn permission_ord_test() {
|
||
assert!(PermissionBuf::from_string_unchecked("bffh.perm".to_string())
|
||
> PermissionBuf::from_string_unchecked("bffh.perm.sub".to_string()));
|
||
}
|
||
|
||
#[test]
|
||
fn permission_simple_check_test() {
|
||
let perm = PermissionBuf::from_string_unchecked("test.perm".to_string());
|
||
let rule = PermRule::Base(perm.clone());
|
||
|
||
assert!(rule.match_perm(&perm));
|
||
}
|
||
|
||
#[test]
|
||
fn permission_children_checks_only_children() {
|
||
let perm = PermissionBuf::from_string_unchecked("test.perm".to_string());
|
||
let rule = PermRule::Children(perm.clone());
|
||
|
||
assert_eq!(rule.match_perm(&perm), false);
|
||
|
||
let perm2 = PermissionBuf::from_string_unchecked("test.perm.child".to_string());
|
||
let perm3 = PermissionBuf::from_string_unchecked("test.perm.child.deeper".to_string());
|
||
assert!(rule.match_perm(&perm2));
|
||
assert!(rule.match_perm(&perm3));
|
||
}
|
||
|
||
#[test]
|
||
fn permission_subtree_checks_base() {
|
||
let perm = PermissionBuf::from_string_unchecked("test.perm".to_string());
|
||
let rule = PermRule::Subtree(perm.clone());
|
||
|
||
assert!(rule.match_perm(&perm));
|
||
|
||
let perm2 = PermissionBuf::from_string_unchecked("test.perm.child".to_string());
|
||
let perm3 = PermissionBuf::from_string_unchecked("test.perm.child.deeper".to_string());
|
||
|
||
assert!(rule.match_perm(&perm2));
|
||
assert!(rule.match_perm(&perm3));
|
||
}
|
||
|
||
#[test]
|
||
fn format_and_read_compatible() {
|
||
use std::convert::TryInto;
|
||
|
||
let testdata = vec![
|
||
("testrole", "testsource"),
|
||
("", "norole"),
|
||
("nosource", "")
|
||
].into_iter().map(|(n,s)| (n.to_string(), s.to_string()));
|
||
|
||
for (name, source) in testdata {
|
||
let role = RoleIdentifier { name, source };
|
||
|
||
let fmt_string = format!("{}", &role);
|
||
|
||
println!("{:?} is formatted: {}", &role, &fmt_string);
|
||
|
||
let parsed: RoleIdentifier = fmt_string.try_into().unwrap();
|
||
|
||
println!("Which parses into {:?}", &parsed);
|
||
|
||
assert_eq!(role, parsed);
|
||
}
|
||
}
|
||
|
||
|
||
#[test]
|
||
fn rules_from_string_test() {
|
||
assert_eq!(
|
||
PermRule::Base(PermissionBuf::from_string_unchecked("bffh.perm".to_string())),
|
||
PermRule::try_from("bffh.perm".to_string()).unwrap()
|
||
);
|
||
assert_eq!(
|
||
PermRule::Children(PermissionBuf::from_string_unchecked("bffh.perm".to_string())),
|
||
PermRule::try_from("bffh.perm.+".to_string()).unwrap()
|
||
);
|
||
assert_eq!(
|
||
PermRule::Subtree(PermissionBuf::from_string_unchecked("bffh.perm".to_string())),
|
||
PermRule::try_from("bffh.perm.*".to_string()).unwrap()
|
||
);
|
||
}
|
||
|
||
#[test]
|
||
fn rules_from_string_edgecases_test() {
|
||
assert!(PermRule::try_from("*".to_string()).is_err());
|
||
assert!(PermRule::try_from("+".to_string()).is_err());
|
||
}
|
||
}
|