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