auth_framework/api/

saml.rs

use crate::api::{ApiResponse, ApiState};
use axum::{
    extract::{Query, State},
    response::{Html, Json},
};
use base64::Engine;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// SAML SSO initiation request
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlSsoRequest {
    pub idp_entity_id: String,
    pub relay_state: Option<String>,
    pub force_authn: Option<bool>,
    pub is_passive: Option<bool>,
}

/// SAML SSO response containing redirect URL
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlSsoResponse {
    pub redirect_url: String,
    pub saml_request: String,
    pub relay_state: Option<String>,
}

/// SAML ACS (Assertion Consumer Service) request
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlAcsRequest {
    #[serde(rename = "SAMLResponse")]
    pub saml_response: String,
    #[serde(rename = "RelayState")]
    pub relay_state: Option<String>,
    #[serde(rename = "SigAlg")]
    pub sig_alg: Option<String>,
    #[serde(rename = "Signature")]
    pub signature: Option<String>,
}

/// SAML metadata configuration
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlMetadataResponse {
    pub entity_id: String,
    pub acs_url: String,
    pub sls_url: Option<String>,
    pub certificate: Option<String>,
    pub name_id_format: String,
}

/// SAML logout request
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlLogoutRequest {
    pub name_id: String,
    pub session_index: Option<String>,
    pub idp_entity_id: String,
}

/// SAML logout response
#[derive(Debug, Serialize, Deserialize)]
pub struct SamlLogoutResponse {
    pub redirect_url: String,
    pub status: String,
}

/// Get SAML metadata for this SP (Service Provider)
pub async fn get_saml_metadata(State(_state): State<ApiState>) -> Html<String> {
    let metadata_xml = r#"<?xml version="1.0" encoding="UTF-8"?>
<md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
                     entityID="https://auth.example.com">
  <md:SPSSODescriptor AuthnRequestsSigned="true" WantAssertionsSigned="true"
                      protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
    <md:NameIDFormat>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</md:NameIDFormat>
    <md:AssertionConsumerService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
                                Location="https://auth.example.com/api/saml/acs"
                                index="0" />
    <md:SingleLogoutService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
                               Location="https://auth.example.com/api/saml/slo" />
  </md:SPSSODescriptor>
</md:EntityDescriptor>"#;

    Html(metadata_xml.to_string())
}

/// Initiate SAML SSO flow
pub async fn initiate_saml_sso(
    State(_state): State<ApiState>,
    Json(request): Json<SamlSsoRequest>,
) -> Json<ApiResponse<SamlSsoResponse>> {
    // Generate SAML AuthnRequest
    let request_id = format!("saml_{}", uuid::Uuid::new_v4());
    let issue_instant = chrono::Utc::now().to_rfc3339();

    let saml_request = format!(
        r#"<samlp:AuthnRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
                           xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
                           ID="{}"
                           Version="2.0"
                           IssueInstant="{}"
                           Destination="https://idp.example.com/sso"
                           {}
                           {}
                           AssertionConsumerServiceURL="https://auth.example.com/api/saml/acs">
  <saml:Issuer>https://auth.example.com</saml:Issuer>
  <samlp:NameIDPolicy Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
                      AllowCreate="true" />
</samlp:AuthnRequest>"#,
        request_id,
        issue_instant,
        request
            .force_authn
            .map_or(String::new(), |fa| format!(r#"ForceAuthn="{}""#, fa)),
        request
            .is_passive
            .map_or(String::new(), |ip| format!(r#"IsPassive="{}""#, ip))
    );

    // Encode SAML request
    let encoded_request = base64::engine::general_purpose::STANDARD.encode(&saml_request);

    // Build redirect URL
    let mut redirect_url = format!(
        "https://idp.example.com/sso?SAMLRequest={}",
        urlencoding::encode(&encoded_request)
    );

    if let Some(relay_state) = &request.relay_state {
        redirect_url.push_str(&format!("&RelayState={}", urlencoding::encode(relay_state)));
    }

    // Store request for validation later
    let _request_key = format!("saml_request:{}", request_id);
    let _request_data = serde_json::json!({
        "request_id": request_id,
        "idp_entity_id": request.idp_entity_id,
        "relay_state": request.relay_state,
        "timestamp": chrono::Utc::now().timestamp()
    });

    Json(ApiResponse::success(SamlSsoResponse {
        redirect_url,
        saml_request: encoded_request,
        relay_state: request.relay_state,
    }))
}

/// Handle SAML ACS (Assertion Consumer Service) - where IdP sends response
pub async fn handle_saml_acs(
    State(_state): State<ApiState>,
    axum::Form(form_data): axum::Form<SamlAcsRequest>,
) -> Json<ApiResponse<serde_json::Value>> {
    // Decode SAML response
    let saml_response_xml =
        match base64::engine::general_purpose::STANDARD.decode(&form_data.saml_response) {
            Ok(decoded) => match String::from_utf8(decoded) {
                Ok(xml) => xml,
                Err(e) => {
                    return Json(ApiResponse::validation_error_typed(format!(
                        "Invalid SAML response UTF-8: {}",
                        e
                    )));
                }
            },
            Err(e) => {
                return Json(ApiResponse::validation_error_typed(format!(
                    "Invalid SAML response encoding: {}",
                    e
                )));
            }
        };

    // Basic SAML response validation (in production, use full XML signature validation)
    if !saml_response_xml.contains("<saml:Assertion") {
        return Json(ApiResponse::validation_error_typed(
            "No SAML assertion found",
        ));
    }

    // Extract user information from assertion (simplified)
    let username = match extract_username_from_saml(&saml_response_xml) {
        Ok(user) => user,
        Err(e) => return Json(ApiResponse::error_typed("SAML_PARSE_ERROR", e)),
    };

    let attributes = match extract_attributes_from_saml(&saml_response_xml) {
        Ok(attrs) => attrs,
        Err(e) => return Json(ApiResponse::error_typed("SAML_PARSE_ERROR", e)),
    };

    // Generate authentication token
    let token_data = serde_json::json!({
        "access_token": format!("saml_token_{}", uuid::Uuid::new_v4()),
        "token_type": "Bearer",
        "expires_in": 3600,
        "user_id": username,
        "authentication_method": "saml",
        "attributes": attributes,
        "relay_state": form_data.relay_state
    });

    Json(ApiResponse::success_with_message(
        token_data,
        "SAML authentication successful",
    ))
}

/// Initiate SAML Single Logout (SLO)
pub async fn initiate_saml_slo(
    State(_state): State<ApiState>,
    Json(request): Json<SamlLogoutRequest>,
) -> Json<ApiResponse<SamlLogoutResponse>> {
    let logout_id = format!("logout_{}", uuid::Uuid::new_v4());
    let issue_instant = chrono::Utc::now().to_rfc3339();

    // Build SAML LogoutRequest
    let saml_logout_request = format!(
        r#"<samlp:LogoutRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
                            xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
                            ID="{}"
                            Version="2.0"
                            IssueInstant="{}"
                            Destination="https://idp.example.com/slo">
  <saml:Issuer>https://auth.example.com</saml:Issuer>
  <saml:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">{}</saml:NameID>
  {}
</samlp:LogoutRequest>"#,
        logout_id,
        issue_instant,
        request.name_id,
        request.session_index.map_or(String::new(), |si| format!(
            r#"<samlp:SessionIndex>{}</samlp:SessionIndex>"#,
            si
        ))
    );

    let encoded_request = base64::engine::general_purpose::STANDARD.encode(&saml_logout_request);
    let redirect_url = format!(
        "https://idp.example.com/slo?SAMLRequest={}",
        urlencoding::encode(&encoded_request)
    );

    Json(ApiResponse::success_with_message(
        SamlLogoutResponse {
            redirect_url,
            status: "logout_initiated".to_string(),
        },
        "SAML logout initiated",
    ))
}

/// Handle SAML SLO response from IdP
pub async fn handle_saml_slo_response(
    State(_state): State<ApiState>,
    Query(params): Query<HashMap<String, String>>,
) -> Json<ApiResponse<()>> {
    let saml_response = match params.get("SAMLResponse") {
        Some(response) => response,
        None => {
            return Json(ApiResponse::validation_error(
                "Missing SAMLResponse parameter",
            ));
        }
    };

    // Decode and validate SLO response (simplified)
    let response_xml = match base64::engine::general_purpose::STANDARD.decode(saml_response) {
        Ok(decoded) => match String::from_utf8(decoded) {
            Ok(xml) => xml,
            Err(e) => {
                return Json(ApiResponse::validation_error(format!(
                    "Invalid SLO response UTF-8: {}",
                    e
                )));
            }
        },
        Err(e) => {
            return Json(ApiResponse::validation_error(format!(
                "Invalid SLO response encoding: {}",
                e
            )));
        }
    };

    // Check for success status (simplified validation)
    if response_xml.contains("urn:oasis:names:tc:SAML:2.0:status:Success") {
        Json(ApiResponse::<()>::ok_with_message(
            "SAML logout completed successfully",
        ))
    } else {
        Json(ApiResponse::error(
            "SAML_LOGOUT_FAILED",
            "SAML logout failed",
        ))
    }
}

/// Create SAML assertion (for Identity Provider functionality)
pub async fn create_saml_assertion(
    State(_state): State<ApiState>,
    Json(request): Json<serde_json::Value>,
) -> Json<ApiResponse<String>> {
    let username = match request["username"].as_str() {
        Some(user) => user,
        None => return Json(ApiResponse::validation_error_typed("Username required")),
    };

    let audience = match request["audience"].as_str() {
        Some(aud) => aud,
        None => return Json(ApiResponse::validation_error_typed("Audience required")),
    };

    // Create SAML assertion (simplified)
    let assertion_xml = format!(
        r#"<saml:Assertion xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
                        ID="assertion_{}"
                        IssueInstant="{}"
                        Version="2.0">
  <saml:Issuer>https://auth.example.com</saml:Issuer>
  <saml:Subject>
    <saml:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">{}@example.com</saml:NameID>
  </saml:Subject>
  <saml:Conditions NotBefore="{}" NotOnOrAfter="{}">
    <saml:AudienceRestriction>
      <saml:Audience>{}</saml:Audience>
    </saml:AudienceRestriction>
  </saml:Conditions>
  <saml:AttributeStatement>
    <saml:Attribute Name="username">
      <saml:AttributeValue>{}</saml:AttributeValue>
    </saml:Attribute>
    <saml:Attribute Name="email">
      <saml:AttributeValue>{}@example.com</saml:AttributeValue>
    </saml:Attribute>
  </saml:AttributeStatement>
</saml:Assertion>"#,
        uuid::Uuid::new_v4(),
        chrono::Utc::now().to_rfc3339(),
        username,
        (chrono::Utc::now() - chrono::Duration::minutes(1)).to_rfc3339(),
        (chrono::Utc::now() + chrono::Duration::hours(1)).to_rfc3339(),
        audience,
        username,
        username
    );

    Json(ApiResponse::success_with_message(
        assertion_xml,
        "SAML assertion created",
    ))
}

/// List configured SAML Identity Providers
pub async fn list_saml_idps(
    State(_state): State<ApiState>,
) -> Json<ApiResponse<Vec<serde_json::Value>>> {
    // In production, retrieve from configuration or database
    let idps = vec![serde_json::json!({
        "entity_id": "https://idp.example.com",
        "certificate": "example_cert",
        "sso_url": "https://idp.example.com/sso",
        "slo_url": "https://idp.example.com/slo"
    })];

    Json(ApiResponse::success_with_message(
        idps,
        "SAML IdPs retrieved",
    ))
}

/// Helper functions
fn extract_username_from_saml(saml_xml: &str) -> Result<String, String> {
    // Simplified extraction - in production, use proper XML parsing
    if let Some(start) = saml_xml.find("<saml:NameID")
        && let Some(content_start) = saml_xml[start..].find('>')
        && let Some(end) = saml_xml[start + content_start + 1..].find("</saml:NameID>")
    {
        let username = &saml_xml[start + content_start + 1..start + content_start + 1 + end];
        return Ok(username.trim().to_string());
    }

    Err("Could not extract username from SAML assertion".to_string())
}

fn extract_attributes_from_saml(saml_xml: &str) -> Result<HashMap<String, Vec<String>>, String> {
    let mut attributes = HashMap::new();

    // Simplified attribute extraction - in production, use proper XML parsing
    if saml_xml.contains("<saml:AttributeStatement>") {
        // Extract attributes (placeholder implementation)
        attributes.insert("source".to_string(), vec!["saml".to_string()]);
        attributes.insert("auth_method".to_string(), vec!["saml_sso".to_string()]);
    }

    Ok(attributes)
}