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|
use super::authorizer::Authorizer;
use cedar_policy::{
Authorizer as CedarAuth, Context, Entities, EntityId, EntityTypeName, EntityUid, PolicySet,
Request as CedarRequest,
};
use envoy_types::ext_authz::v3::pb::CheckRequest;
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 http_request = match request
.attributes
.as_ref()
.and_then(|attr| attr.request.as_ref())
.and_then(|req| req.http.as_ref())
{
Some(http) => http,
None => return false,
};
tracing::info!(
method = %http_request.method,
host = %http_request.host,
path = %http_request.path,
scheme = %http_request.scheme,
protocol = %http_request.protocol,
"Processing HTTP request"
);
match self.map_from(http_request.clone()) {
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(e) => {
println!("error: {}", e);
tracing::error!(
error = %e,
path = %http_request.path,
"Failed to create Cedar request"
);
false
}
}
}
}
impl CedarAuthorizer {
fn map_from(
&self,
http_request: envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<CedarRequest, Box<dyn std::error::Error>> {
let principal = self.principal_from(&http_request)?;
let permission = self.permission_from(&http_request)?;
let resource = self.resource_from(&http_request)?;
let context = self.context_from(http_request)?;
CedarRequest::new(principal, permission, resource, context, None)
.map_err(|e| Box::new(e) as Box<dyn std::error::Error>)
}
fn principal_from(
&self,
_http_request: &envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::EntityUid, Box<dyn std::error::Error>> {
Ok(EntityUid::from_type_name_and_id(
EntityTypeName::from_str("User")?,
EntityId::from_str("client")?,
))
}
fn permission_from(
&self,
_http_request: &envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::EntityUid, Box<dyn std::error::Error>> {
Ok(EntityUid::from_type_name_and_id(
EntityTypeName::from_str("Action")?,
EntityId::from_str("check")?,
))
}
fn resource_from(
&self,
_http_request: &envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::EntityUid, Box<dyn std::error::Error>> {
Ok(EntityUid::from_type_name_and_id(
EntityTypeName::from_str("Resource")?,
EntityId::from_str("resource")?,
))
}
fn context_from(
&self,
http_request: envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::Context, cedar_policy::ContextCreationError> {
let mut items = std::collections::HashMap::new();
items.insert("bearer_token".to_string(), self.token_from(&http_request));
items.insert("host".to_string(), self.safe_string(&http_request.host));
items.insert("method".to_string(), self.safe_string(&http_request.method));
items.insert("path".to_string(), self.safe_string(&http_request.path));
Context::from_pairs(items.into_iter().collect::<Vec<_>>())
}
fn token_from(
&self,
http_request: &envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> cedar_policy::RestrictedExpression {
let bearer_token = &http_request
.headers
.get("authorization")
.and_then(|auth| auth.strip_prefix("Bearer "))
.unwrap_or("");
self.safe_string(bearer_token)
}
fn safe_string(&self, item: &str) -> cedar_policy::RestrictedExpression {
cedar_policy::RestrictedExpression::new_string(item.to_string())
}
}
|
