File size: 7,214 Bytes
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use super::policy::Policy;
use crate::PolicyConfig;
use crate::policies::Permission;
/// High-level policy engine that provides convenient methods for checking
/// policies
///
/// This wrapper around Workflow provides easy-to-use methods for services to
/// check if operations are allowed without having to construct Operation enums
/// manually.
pub struct PolicyEngine<'a> {
policies: &'a PolicyConfig,
}
impl<'a> PolicyEngine<'a> {
/// Create a new PolicyEngine from a workflow
pub fn new(policies: &'a PolicyConfig) -> Self {
Self { policies }
}
/// Check if an operation is allowed
/// Returns permission result
pub fn can_perform(&self, operation: &PermissionOperation) -> Permission {
self.evaluate_policies(operation)
}
/// Internal helper function to evaluate policies for a given operation
/// Returns permission result, defaults to Confirm if no policies match
fn evaluate_policies(&self, operation: &PermissionOperation) -> Permission {
let has_policies = !self.policies.policies.is_empty();
if !has_policies {
return Permission::Confirm;
}
let mut last_allow: Option<Permission> = None;
// Evaluate all policies in order: workflow policies first, then extended
// policies
if let Some(permission) = self.evaluate_policy_set(self.policies.policies.iter(), operation)
{
match permission {
Permission::Deny | Permission::Confirm => {
// Return immediately for denials or confirmations
return permission;
}
Permission::Allow => {
// Keep track of the last allow
last_allow = Some(permission);
}
}
}
// Return last allow if found, otherwise default to Confirm
last_allow.unwrap_or(Permission::Confirm)
}
/// Helper function to evaluate a set of policies
/// Returns the first non-Allow result, or the last Allow result if all are
/// Allow
fn evaluate_policy_set<'p, I: IntoIterator<Item = &'p Policy>>(
&self,
policies: I,
operation: &PermissionOperation,
) -> Option<Permission> {
let mut last_allow: Option<Permission> = None;
for policy in policies {
if let Some(permission) = policy.eval(operation) {
match permission {
Permission::Deny | Permission::Confirm => {
// Return immediately for denials or confirmations
return Some(permission);
}
Permission::Allow => {
// Keep track of the last allow
last_allow = Some(permission);
}
}
}
}
last_allow
}
}
#[cfg(test)]
mod tests {
use pretty_assertions::assert_eq;
use super::*;
use crate::{ExecuteRule, Fetch, Permission, Policy, PolicyConfig, ReadRule, Rule, WriteRule};
fn fixture_workflow_with_read_policy() -> PolicyConfig {
PolicyConfig::new().add_policy(Policy::Simple {
permission: Permission::Allow,
rule: Rule::Read(ReadRule { read: "src/**/*.rs".to_string(), dir: None }),
})
}
fn fixture_workflow_with_write_policy() -> PolicyConfig {
PolicyConfig::new().add_policy(Policy::Simple {
permission: Permission::Deny,
rule: Rule::Write(WriteRule { write: "**/*.rs".to_string(), dir: None }),
})
}
fn fixture_workflow_with_execute_policy() -> PolicyConfig {
PolicyConfig::new().add_policy(Policy::Simple {
permission: Permission::Allow,
rule: Rule::Execute(ExecuteRule { command: "cargo *".to_string(), dir: None }),
})
}
fn fixture_workflow_with_write_policy_confirm() -> PolicyConfig {
PolicyConfig::new().add_policy(Policy::Simple {
permission: Permission::Confirm,
rule: Rule::Write(WriteRule { write: "src/**/*.rs".to_string(), dir: None }),
})
}
fn fixture_workflow_with_net_fetch_policy() -> PolicyConfig {
PolicyConfig::new().add_policy(Policy::Simple {
permission: Permission::Allow,
rule: Rule::Fetch(Fetch { url: "https://api.example.com/*".to_string(), dir: None }),
})
}
#[test]
fn test_policy_engine_can_perform_read() {
let fixture_workflow = fixture_workflow_with_read_policy();
let fixture = PolicyEngine::new(&fixture_workflow);
let operation = PermissionOperation::Read {
path: std::path::PathBuf::from("src/main.rs"),
cwd: std::path::PathBuf::from("/test/cwd"),
message: "Read file: src/main.rs".to_string(),
};
let actual = fixture.can_perform(&operation);
assert_eq!(actual, Permission::Allow);
}
#[test]
fn test_policy_engine_can_perform_write() {
let fixture_workflow = fixture_workflow_with_write_policy();
let fixture = PolicyEngine::new(&fixture_workflow);
let operation = PermissionOperation::Write {
path: std::path::PathBuf::from("src/main.rs"),
cwd: std::path::PathBuf::from("/test/cwd"),
message: "Create/overwrite file: src/main.rs".to_string(),
};
let actual = fixture.can_perform(&operation);
assert_eq!(actual, Permission::Deny);
}
#[test]
fn test_policy_engine_can_perform_write_with_confirm() {
let fixture_workflow = fixture_workflow_with_write_policy_confirm();
let fixture = PolicyEngine::new(&fixture_workflow);
let operation = PermissionOperation::Write {
path: std::path::PathBuf::from("src/main.rs"),
cwd: std::path::PathBuf::from("/test/cwd"),
message: "Create/overwrite file: src/main.rs".to_string(),
};
let actual = fixture.can_perform(&operation);
assert_eq!(actual, Permission::Confirm);
}
#[test]
fn test_policy_engine_can_perform_execute() {
let fixture_workflow = fixture_workflow_with_execute_policy();
let fixture = PolicyEngine::new(&fixture_workflow);
let operation = PermissionOperation::Execute {
command: "cargo build".to_string(),
cwd: std::path::PathBuf::from("/test/cwd"),
};
let actual = fixture.can_perform(&operation);
assert_eq!(actual, Permission::Allow);
}
#[test]
fn test_policy_engine_can_perform_net_fetch() {
let fixture_workflow = fixture_workflow_with_net_fetch_policy();
let fixture = PolicyEngine::new(&fixture_workflow);
let operation = PermissionOperation::Fetch {
url: "https://api.example.com/data".to_string(),
cwd: std::path::PathBuf::from("/test/cwd"),
message: "Fetch content from URL: https://api.example.com/data".to_string(),
};
let actual = fixture.can_perform(&operation);
assert_eq!(actual, Permission::Allow);
}
}
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