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|
use super::authorizer::Authorizer;
use std::fs;
use std::str::FromStr;
#[derive(Debug)]
pub struct CedarAuthorizer {
authorizer: cedar_policy::Authorizer,
entities: cedar_policy::Entities,
policies: cedar_policy::PolicySet,
}
impl CedarAuthorizer {
pub fn new(
policies: cedar_policy::PolicySet,
entities: cedar_policy::Entities,
) -> CedarAuthorizer {
CedarAuthorizer {
policies,
entities,
authorizer: cedar_policy::Authorizer::new(),
}
}
pub fn new_from(path: &std::path::Path, entities: cedar_policy::Entities) -> CedarAuthorizer {
Self::new(
Self::load_from(path).unwrap_or_else(|e| {
tracing::error!(
path = ?path,
error = %e,
"Failed to load Cedar policies, using empty policy set"
);
cedar_policy::PolicySet::default()
}),
entities,
)
}
fn load_from(
path: &std::path::Path,
) -> Result<cedar_policy::PolicySet, Box<dyn std::error::Error>> {
if !path.exists() {
return Ok(cedar_policy::PolicySet::default());
}
if path.is_file() && path.extension().map_or(false, |ext| ext == "cedar") {
let content = fs::read_to_string(&path)?;
return Ok(cedar_policy::PolicySet::from_str(&content)?);
}
if !path.is_dir() {
return Ok(cedar_policy::PolicySet::default());
}
let mut policies = cedar_policy::PolicySet::new();
for entry in fs::read_dir(path)? {
policies.merge(&Self::load_from(&entry?.path())?, true)?;
}
return Ok(policies);
}
fn map_from(
&self,
http_request: envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::Request, 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)?;
Ok(cedar_policy::Request::new(
principal, permission, resource, context, None,
)?)
}
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>> {
let subject = http_request
.headers
.get("x-jwt-claim-sub")
.map_or("", |v| v);
Ok(cedar_policy::EntityUid::from_type_name_and_id(
cedar_policy::EntityTypeName::from_str("User")?,
cedar_policy::EntityId::from_str(subject)?,
))
}
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(cedar_policy::EntityUid::from_type_name_and_id(
cedar_policy::EntityTypeName::from_str("Action")?,
cedar_policy::EntityId::from_str(&http_request.method)?,
))
}
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(cedar_policy::EntityUid::from_type_name_and_id(
cedar_policy::EntityTypeName::from_str("Resource")?,
cedar_policy::EntityId::from_str(&http_request.path)?,
))
}
fn context_from(
&self,
http_request: envoy_types::pb::envoy::service::auth::v3::attribute_context::HttpRequest,
) -> Result<cedar_policy::Context, Box<dyn std::error::Error>> {
let mut items = std::collections::HashMap::new();
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));
Ok(cedar_policy::Context::from_pairs(
items.into_iter().collect::<Vec<_>>(),
)?)
}
fn safe_string(&self, item: &str) -> cedar_policy::RestrictedExpression {
cedar_policy::RestrictedExpression::new_string(item.to_string())
}
}
impl Default for CedarAuthorizer {
fn default() -> Self {
Self::new_from(
std::path::Path::new("/etc/authzd"),
cedar_policy::Entities::empty(),
)
}
}
impl Authorizer for CedarAuthorizer {
fn authorize(&self, request: envoy_types::ext_authz::v3::pb::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,
};
match self.map_from(http_request.clone()) {
Ok(cedar_request) => {
let response =
self.authorizer
.is_authorized(&cedar_request, &self.policies, &self.entities);
let decision = response.decision();
tracing::info!(
method = %http_request.method,
host = %http_request.host,
path = %http_request.path,
scheme = %http_request.scheme,
protocol = %http_request.protocol,
decision = ?decision,
diagnostics = ?response.diagnostics(),
"Processing HTTP request"
);
matches!(decision, cedar_policy::Decision::Allow)
}
Err(e) => {
tracing::error!(
error = %e,
path = %http_request.path,
"Failed to create Cedar request"
);
false
}
}
}
}
|
