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// //! A filter for cross-site request forgery (CSRF).
// //!
// //! This middleware is stateless and [based on request
// //! headers](https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#Verifying_Same_Origin_with_Standard_Headers).
// //!
// //! By default requests are allowed only if one of these is true:
// //!
// //! * The request method is safe (`GET`, `HEAD`, `OPTIONS`). It is the
// //! applications responsibility to ensure these methods cannot be used to
// //! execute unwanted actions. Note that upgrade requests for websockets are
// //! also considered safe.
// //! * The `Origin` header (added automatically by the browser) matches one
// //! of the allowed origins.
// //! * There is no `Origin` header but the `Referer` header matches one of
// //! the allowed origins.
// //!
// //! Use [`CsrfFilter::allow_xhr()`](struct.CsrfFilter.html#method.allow_xhr)
// //! if you want to allow requests with unprotected methods via
// //! [CORS](../cors/struct.Cors.html).
// //!
// //! # Example
// //!
// //! ```
// //! # extern crate actix_web;
// //! use actix_web::middleware::csrf;
// //! use actix_web::{http, App, HttpRequest, HttpResponse};
// //!
// //! fn handle_post(_: &HttpRequest) -> &'static str {
// //! "This action should only be triggered with requests from the same site"
// //! }
// //!
// //! fn main() {
// //! let app = App::new()
// //! .middleware(
// //! csrf::CsrfFilter::new().allowed_origin("https://www.example.com"),
// //! )
// //! .resource("/", |r| {
// //! r.method(http::Method::GET).f(|_| HttpResponse::Ok());
// //! r.method(http::Method::POST).f(handle_post);
// //! })
// //! .finish();
// //! }
// //! ```
// //!
// //! In this example the entire application is protected from CSRF.
// use std::borrow::Cow;
// use std::collections::HashSet;
// use bytes::Bytes;
// use error::{ResponseError, Result};
// use http::{header, HeaderMap, HttpTryFrom, Uri};
// use httprequest::HttpRequest;
// use httpresponse::HttpResponse;
// use middleware::{Middleware, Started};
// use server::Request;
// /// Potential cross-site request forgery detected.
// #[derive(Debug, Fail)]
// pub enum CsrfError {
// /// The HTTP request header `Origin` was required but not provided.
// #[fail(display = "Origin header required")]
// MissingOrigin,
// /// The HTTP request header `Origin` could not be parsed correctly.
// #[fail(display = "Could not parse Origin header")]
// BadOrigin,
// /// The cross-site request was denied.
// #[fail(display = "Cross-site request denied")]
// CsrDenied,
// }
// impl ResponseError for CsrfError {
// fn error_response(&self) -> HttpResponse {
// HttpResponse::Forbidden().body(self.to_string())
// }
// }
// fn uri_origin(uri: &Uri) -> Option<String> {
// match (
// uri.scheme_part(),
// uri.host(),
// uri.port_part().map(|port| port.as_u16()),
// ) {
// (Some(scheme), Some(host), Some(port)) => Some(format!("{}://{}:{}", scheme, host, port)),
// (Some(scheme), Some(host), None) => Some(format!("{}://{}", scheme, host)),
// _ => None,
// }
// }
// fn origin(headers: &HeaderMap) -> Option<Result<Cow<str>, CsrfError>> {
// headers
// .get(header::ORIGIN)
// .map(|origin| {
// origin
// .to_str()
// .map_err(|_| CsrfError::BadOrigin)
// .map(|o| o.into())
// })
// .or_else(|| {
// headers.get(header::REFERER).map(|referer| {
// Uri::try_from(Bytes::from(referer.as_bytes()))
// .ok()
// .as_ref()
// .and_then(uri_origin)
// .ok_or(CsrfError::BadOrigin)
// .map(|o| o.into())
// })
// })
// }
// /// A middleware that filters cross-site requests.
// ///
// /// To construct a CSRF filter:
// ///
// /// 1. Call [`CsrfFilter::build`](struct.CsrfFilter.html#method.build) to
// /// start building.
// /// 2. [Add](struct.CsrfFilterBuilder.html#method.allowed_origin) allowed
// /// origins.
// /// 3. Call [finish](struct.CsrfFilterBuilder.html#method.finish) to retrieve
// /// the constructed filter.
// ///
// /// # Example
// ///
// /// ```
// /// use actix_web::middleware::csrf;
// /// use actix_web::App;
// ///
// /// # fn main() {
// /// let app = App::new()
// /// .middleware(csrf::CsrfFilter::new().allowed_origin("https://www.example.com"));
// /// # }
// /// ```
// #[derive(Default)]
// pub struct CsrfFilter {
// origins: HashSet<String>,
// allow_xhr: bool,
// allow_missing_origin: bool,
// allow_upgrade: bool,
// }
// impl CsrfFilter {
// /// Start building a `CsrfFilter`.
// pub fn new() -> CsrfFilter {
// CsrfFilter {
// origins: HashSet::new(),
// allow_xhr: false,
// allow_missing_origin: false,
// allow_upgrade: false,
// }
// }
// /// Add an origin that is allowed to make requests. Will be verified
// /// against the `Origin` request header.
// pub fn allowed_origin<T: Into<String>>(mut self, origin: T) -> CsrfFilter {
// self.origins.insert(origin.into());
// self
// }
// /// Allow all requests with an `X-Requested-With` header.
// ///
// /// A cross-site attacker should not be able to send requests with custom
// /// headers unless a CORS policy whitelists them. Therefore it should be
// /// safe to allow requests with an `X-Requested-With` header (added
// /// automatically by many JavaScript libraries).
// ///
// /// This is disabled by default, because in Safari it is possible to
// /// circumvent this using redirects and Flash.
// ///
// /// Use this method to enable more lax filtering.
// pub fn allow_xhr(mut self) -> CsrfFilter {
// self.allow_xhr = true;
// self
// }
// /// Allow requests if the expected `Origin` header is missing (and
// /// there is no `Referer` to fall back on).
// ///
// /// The filter is conservative by default, but it should be safe to allow
// /// missing `Origin` headers because a cross-site attacker cannot prevent
// /// the browser from sending `Origin` on unprotected requests.
// pub fn allow_missing_origin(mut self) -> CsrfFilter {
// self.allow_missing_origin = true;
// self
// }
// /// Allow cross-site upgrade requests (for example to open a WebSocket).
// pub fn allow_upgrade(mut self) -> CsrfFilter {
// self.allow_upgrade = true;
// self
// }
// fn validate(&self, req: &Request) -> Result<(), CsrfError> {
// let is_upgrade = req.headers().contains_key(header::UPGRADE);
// let is_safe = req.method().is_safe() && (self.allow_upgrade || !is_upgrade);
// if is_safe || (self.allow_xhr && req.headers().contains_key("x-requested-with")) {
// Ok(())
// } else if let Some(header) = origin(req.headers()) {
// match header {
// Ok(ref origin) if self.origins.contains(origin.as_ref()) => Ok(()),
// Ok(_) => Err(CsrfError::CsrDenied),
// Err(err) => Err(err),
// }
// } else if self.allow_missing_origin {
// Ok(())
// } else {
// Err(CsrfError::MissingOrigin)
// }
// }
// }
// impl<S> Middleware<S> for CsrfFilter {
// fn start(&self, req: &HttpRequest<S>) -> Result<Started> {
// self.validate(req)?;
// Ok(Started::Done)
// }
// }
// #[cfg(test)]
// mod tests {
// use super::*;
// use http::Method;
// use test::TestRequest;
// #[test]
// fn test_safe() {
// let csrf = CsrfFilter::new().allowed_origin("https://www.example.com");
// let req = TestRequest::with_header("Origin", "https://www.w3.org")
// .method(Method::HEAD)
// .finish();
// assert!(csrf.start(&req).is_ok());
// }
// #[test]
// fn test_csrf() {
// let csrf = CsrfFilter::new().allowed_origin("https://www.example.com");
// let req = TestRequest::with_header("Origin", "https://www.w3.org")
// .method(Method::POST)
// .finish();
// assert!(csrf.start(&req).is_err());
// }
// #[test]
// fn test_referer() {
// let csrf = CsrfFilter::new().allowed_origin("https://www.example.com");
// let req =
// TestRequest::with_header("Referer", "https://www.example.com/some/path?query=param")
// .method(Method::POST)
// .finish();
// assert!(csrf.start(&req).is_ok());
// }
// #[test]
// fn test_upgrade() {
// let strict_csrf = CsrfFilter::new().allowed_origin("https://www.example.com");
// let lax_csrf = CsrfFilter::new()
// .allowed_origin("https://www.example.com")
// .allow_upgrade();
// let req = TestRequest::with_header("Origin", "https://cswsh.com")
// .header("Connection", "Upgrade")
// .header("Upgrade", "websocket")
// .method(Method::GET)
// .finish();
// assert!(strict_csrf.start(&req).is_err());
// assert!(lax_csrf.start(&req).is_ok());
// }
// }
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