Merge pull request #113 from niklasf/csrf-upgrade

Let CSRF filter catch cross-site upgrades

src/middleware/csrf.rs

@@ -116,22 +116,27 @@ pub struct CsrfFilter {
     origins: HashSet<String>,
     allow_xhr: bool,
     allow_missing_origin: bool,
+    allow_upgrade: bool,
 }
 
 impl CsrfFilter {
     /// Start building a `CsrfFilter`.
     pub fn build() -> CsrfFilterBuilder {
         CsrfFilterBuilder {
-            cors: CsrfFilter {
+            csrf: CsrfFilter {
                 origins: HashSet::new(),
                 allow_xhr: false,
                 allow_missing_origin: false,
+                allow_upgrade: false,
             }
         }
     }
 
     fn validate<S>(&self, req: &mut HttpRequest<S>) -> Result<(), CsrfError> {
-        if req.method().is_safe() || (self.allow_xhr && req.headers().contains_key("x-requested-with")) {
+        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 {
@@ -175,14 +180,14 @@ impl<S> Middleware<S> for CsrfFilter {
 ///     .finish();
 /// ```
 pub struct CsrfFilterBuilder {
-    cors: CsrfFilter,
+    csrf: CsrfFilter,
 }
 
 impl CsrfFilterBuilder {
     /// Add an origin that is allowed to make requests. Will be verified
     /// against the `Origin` request header.
     pub fn allowed_origin(mut self, origin: &str) -> CsrfFilterBuilder {
-        self.cors.origins.insert(origin.to_owned());
+        self.csrf.origins.insert(origin.to_owned());
         self
     }
 
@@ -198,7 +203,7 @@ impl CsrfFilterBuilder {
     ///
     /// Use this method to enable more lax filtering.
     pub fn allow_xhr(mut self) -> CsrfFilterBuilder {
-        self.cors.allow_xhr = true;
+        self.csrf.allow_xhr = true;
         self
     }
 
@@ -209,13 +214,19 @@ impl CsrfFilterBuilder {
     /// missing `Origin` headers because a cross-site attacker cannot prevent
     /// the browser from sending `Origin` on unsafe requests.
     pub fn allow_missing_origin(mut self) -> CsrfFilterBuilder {
-        self.cors.allow_missing_origin = true;
+        self.csrf.allow_missing_origin = true;
+        self
+    }
+
+    /// Allow cross-site upgrade requests (for example to open a WebSocket).
+    pub fn allow_upgrade(mut self) -> CsrfFilterBuilder {
+        self.csrf.allow_upgrade = true;
         self
     }
 
     /// Finishes building the `CsrfFilter` instance.
     pub fn finish(self) -> CsrfFilter {
-        self.cors
+        self.csrf
     }
 }
 
@@ -263,4 +274,25 @@ mod tests {
 
         assert!(csrf.start(&mut req).is_ok());
     }
+
+    #[test]
+    fn test_upgrade() {
+        let strict_csrf = CsrfFilter::build()
+            .allowed_origin("https://www.example.com")
+            .finish();
+
+        let lax_csrf = CsrfFilter::build()
+            .allowed_origin("https://www.example.com")
+            .allow_upgrade()
+            .finish();
+
+        let mut req = TestRequest::with_header("Origin", "https://cswsh.com")
+            .header("Connection", "Upgrade")
+            .header("Upgrade", "websocket")
+            .method(Method::GET)
+            .finish();
+
+        assert!(strict_csrf.start(&mut req).is_err());
+        assert!(lax_csrf.start(&mut req).is_ok());
+    }
 }