fabaccess-bffh/bffhd/authorization/roles.rs
2022-06-02 17:46:36 +02:00

170 lines
5.8 KiB
Rust

use crate::authorization::permissions::{PermRule, Permission};
use crate::users::db::UserData;
use once_cell::sync::OnceCell;
use std::collections::{HashMap, HashSet};
use std::fmt;
static ROLES: OnceCell<HashMap<String, Role>> = OnceCell::new();
#[derive(Copy, Clone)]
pub struct Roles {
roles: &'static HashMap<String, Role>,
}
impl Roles {
pub fn new(roles: HashMap<String, Role>) -> Self {
let span = tracing::debug_span!("roles", "Creating Roles handle");
let _guard = span.enter();
let this = ROLES.get_or_init(|| {
tracing::debug!("Initializing global roles…");
roles
});
Self { roles: this }
}
pub fn get(self, roleid: &str) -> Option<&Role> {
self.roles.get(roleid)
}
/// Tally a role dependency tree into a set
///
/// A Default implementation exists which adapter may overwrite with more efficient
/// implementations.
fn tally_role(&self, roles: &mut HashMap<String, Role>, role_id: &String) {
if let Some(role) = self.get(role_id) {
// Only check and tally parents of a role at the role itself if it's the first time we
// see it
if !roles.contains_key(role_id) {
for parent in role.parents.iter() {
self.tally_role(roles, parent);
}
roles.insert(role_id.clone(), role.clone());
}
}
}
fn collect_permrules(&self, user: &UserData) -> Vec<PermRule> {
let mut roleset = HashMap::new();
for role_id in user.roles.iter() {
self.tally_role(&mut roleset, role_id);
}
let mut output = Vec::new();
// Iter all unique role->permissions we've found and early return on match.
for (_roleid, role) in roleset.iter() {
output.extend(role.permissions.iter().cloned())
}
output
}
fn permitted_tally(
&self,
roles: &mut HashSet<String>,
role_id: &String,
perm: &Permission,
) -> bool {
let _guard = tracing::debug_span!("tally", %role_id, perm=perm.as_str());
if let Some(role) = self.get(role_id) {
// Only check and tally parents of a role at the role itself if it's the first time we
// see it
if !roles.contains(role_id) {
for perm_rule in role.permissions.iter() {
if perm_rule.match_perm(perm) {
tracing::debug!("Permission granted by direct role");
return true;
}
}
for parent in role.parents.iter() {
if self.permitted_tally(roles, parent, perm) {
tracing::debug!(%parent, "Permission granted by parent role");
return true;
}
}
roles.insert(role_id.clone());
}
}
tracing::trace!(%role_id, "Permission not granted by role");
false
}
pub fn is_permitted(&self, user: &UserData, perm: impl AsRef<Permission>) -> bool {
let perm = perm.as_ref();
tracing::debug!(perm = perm.as_str(), "Checking permission");
let mut seen = HashSet::new();
for role_id in user.roles.iter() {
if self.permitted_tally(&mut seen, role_id, perm.as_ref()) {
return true;
}
}
false
}
}
/// A "Role" from the Authorization perspective
///
/// You can think of a role as a bundle of permissions relating to other roles. In most cases a
/// role represents a real-world education or apprenticeship, which gives a person the education
/// necessary to use a machine safely.
/// Roles are assigned permissions which in most cases evaluate to granting a person the right to
/// use certain (potentially) dangerous machines.
/// Using this indirection makes administration easier in certain ways; instead of maintaining
/// permissions on users directly the user is given a role after having been educated on the safety
/// of a machine; if later on a similar enough machine is put to use the administrator can just add
/// the permission for that machine to an already existing role instead of manually having to
/// assign to all users.
#[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
pub struct Role {
// If a role doesn't define parents, default to an empty Vec.
#[serde(default, skip_serializing_if = "Vec::is_empty")]
/// A Role can have parents, inheriting all permissions
///
/// This makes situations where different levels of access are required easier: Each higher
/// level of access sets the lower levels of access as parent, inheriting their permission; if
/// you are allowed to manage a machine you are then also allowed to use it and so on
parents: Vec<String>,
// If a role doesn't define permissions, default to an empty Vec.
#[serde(default, skip_serializing_if = "Vec::is_empty")]
permissions: Vec<PermRule>,
}
impl Role {
pub fn new(parents: Vec<String>, permissions: Vec<PermRule>) -> Self {
Self {
parents,
permissions,
}
}
}
impl fmt::Display for Role {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "parents:")?;
if self.parents.is_empty() {
writeln!(f, " []")?;
} else {
writeln!(f, "")?;
for p in self.parents.iter() {
writeln!(f, " - {}", p)?;
}
}
write!(f, "permissions:")?;
if self.permissions.is_empty() {
writeln!(f, " []")?;
} else {
writeln!(f, "")?;
for p in self.permissions.iter() {
writeln!(f, " - {}", p)?;
}
}
Ok(())
}
}