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|
use super::authorizer::Authorizer;
use cedar_policy::{
Authorizer as CedarAuth, Context, Entities, EntityId, EntityTypeName, EntityUid, PolicySet,
Request as CedarRequest, RestrictedExpression,
};
use envoy_types::ext_authz::v3::pb::CheckRequest;
use std::collections::HashMap;
use std::fs;
use std::str::FromStr;
#[derive(Debug)]
pub struct CedarAuthorizer {
policies: PolicySet,
authorizer: CedarAuth,
}
impl CedarAuthorizer {
pub fn new(policies: cedar_policy::PolicySet) -> CedarAuthorizer {
CedarAuthorizer {
policies,
authorizer: CedarAuth::new(),
}
}
pub fn new_from(path: &std::path::Path) -> CedarAuthorizer {
Self::new(Self::load_from(path).unwrap_or_else(|_| PolicySet::default()))
}
fn load_from(path: &std::path::Path) -> Result<PolicySet, Box<dyn std::error::Error>> {
if !path.exists() || !path.is_dir() {
return Ok(PolicySet::default());
}
let mut policies = PolicySet::new();
for entry in fs::read_dir(path)? {
let file_path = entry?.path();
if let Some(extension) = file_path.extension() {
if extension == "cedar" {
let content = fs::read_to_string(&file_path)?;
let file_policies = PolicySet::from_str(&content)?;
for policy in file_policies.policies() {
policies.add(policy.clone())?;
}
}
}
}
Ok(policies)
}
}
impl Default for CedarAuthorizer {
fn default() -> Self {
Self::new_from(std::path::Path::new("/etc/authzd"))
}
}
impl Authorizer for CedarAuthorizer {
fn authorize(&self, request: CheckRequest) -> bool {
let headers = match request
.attributes
.as_ref()
.and_then(|attr| attr.request.as_ref())
.and_then(|req| req.http.as_ref())
.map(|http| &http.headers)
{
Some(headers) => headers,
None => return false,
};
// Extract authorization token
let bearer_token = headers
.get("authorization")
.and_then(|auth| auth.strip_prefix("Bearer "))
.unwrap_or("");
// Extract request path for static asset checking
let path = headers
.get(":path")
.or_else(|| headers.get("path"))
.map_or("", |v| v.as_str());
// Create Cedar entities and request
match self.create_cedar_request(bearer_token, path) {
Ok(cedar_request) => {
let entities = Entities::empty();
let response =
self.authorizer
.is_authorized(&cedar_request, &self.policies, &entities);
matches!(response.decision(), cedar_policy::Decision::Allow)
}
Err(_) => false,
}
}
}
impl CedarAuthorizer {
fn create_cedar_request(
&self,
bearer_token: &str,
path: &str,
) -> Result<CedarRequest, Box<dyn std::error::Error>> {
// Create principal entity
let principal_id = EntityId::from_str("client")?;
let principal_type = EntityTypeName::from_str("User")?;
let principal = EntityUid::from_type_name_and_id(principal_type, principal_id);
// Create action entity
let action_id = EntityId::from_str("check")?;
let action_type = EntityTypeName::from_str("Action")?;
let action = EntityUid::from_type_name_and_id(action_type, action_id);
// Create resource entity
let resource_id = EntityId::from_str("resource")?;
let resource_type = EntityTypeName::from_str("Resource")?;
let resource = EntityUid::from_type_name_and_id(resource_type, resource_id);
// Create context with bearer token and path
let mut context_map = HashMap::new();
if !bearer_token.is_empty() {
context_map.insert(
"bearer_token".to_string(),
RestrictedExpression::from_str(&format!("\"{bearer_token}\""))?,
);
}
if !path.is_empty() {
context_map.insert(
"path".to_string(),
RestrictedExpression::from_str(&format!("\"{path}\""))?,
);
}
let context = Context::from_pairs(context_map.into_iter().collect::<Vec<_>>())?;
CedarRequest::new(principal, action, resource, context, None)
.map_err(|e| Box::new(e) as Box<dyn std::error::Error>)
}
}
|
