Support configurable 'X-Forwarded-Proto'.

Co-authored-by: Sergio Benitez <sb@sergio.bz>

core/http/src/header/mod.rs

@@ -4,10 +4,12 @@ mod media_type;
 mod content_type;
 mod accept;
 mod header;
+mod proxy_proto;
 
 pub use self::content_type::ContentType;
 pub use self::accept::{Accept, QMediaType};
 pub use self::media_type::MediaType;
 pub use self::header::{Header, HeaderMap};
+pub use self::proxy_proto::ProxyProto;
 
 pub(crate) use self::media_type::Source;

core/http/src/header/proxy_proto.rs

@@ -0,0 +1,51 @@
+use std::fmt;
+
+use uncased::{UncasedStr, AsUncased};
+
+/// A protocol used to identify a specific protocol forwarded by an HTTP proxy.
+/// Value are case-insensitive.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum ProxyProto<'a> {
+    /// `http` value, Hypertext Transfer Protocol.
+    Http,
+    /// `https` value, Hypertext Transfer Protocol Secure.
+    Https,
+    /// Any protocol name other than `http` or `https`.
+    Unknown(&'a UncasedStr),
+}
+
+impl ProxyProto<'_> {
+    /// Returns `true` if `self` is `ProxyProto::Https` and `false` otherwise.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use rocket::http::ProxyProto;
+    ///
+    /// assert!(ProxyProto::Https.is_https());
+    /// assert!(!ProxyProto::Http.is_https());
+    /// ```
+    pub fn is_https(&self) -> bool {
+        self == &ProxyProto::Https
+    }
+}
+
+impl<'a> From<&'a str> for ProxyProto<'a> {
+    fn from(value: &'a str) -> ProxyProto<'a> {
+        match value.as_uncased() {
+            v if v == "http" => ProxyProto::Http,
+            v if v == "https" => ProxyProto::Https,
+            v => ProxyProto::Unknown(v)
+        }
+    }
+}
+
+impl fmt::Display for ProxyProto<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match *self {
+            ProxyProto::Http => "http",
+            ProxyProto::Https => "https",
+            ProxyProto::Unknown(s) => s.as_str(),
+        })
+    }
+}

core/lib/src/config/config.rs

@@ -85,13 +85,28 @@ pub struct Config {
     /// client. Used internally and by [`Request::client_ip()`] and
     /// [`Request::real_ip()`].
     ///
-    /// To disable using any header for this purpose, set this value to `false`.
+    /// To disable using any header for this purpose, set this value to `false`
-    /// Deserialization semantics are identical to those of [`Ident`] except
+    /// or `None`. Deserialization semantics are identical to those of [`Ident`]
-    /// that the value must syntactically be a valid HTTP header name.
+    /// except that the value must syntactically be a valid HTTP header name.
     ///
     /// **(default: `"X-Real-IP"`)**
-    #[serde(deserialize_with = "crate::config::ip_header::deserialize")]
+    #[serde(deserialize_with = "crate::config::http_header::deserialize")]
     pub ip_header: Option<Uncased<'static>>,
+    /// The name of a header, whose value is typically set by an intermediary
+    /// server or proxy, which contains the protocol (HTTP or HTTPS) used by the
+    /// connecting client. This should probably be [`X-Forwarded-Proto`], as
+    /// that is the de facto standard. Used by [`Request::forwarded_proto()`]
+    /// to determine the forwarded protocol and [`Request::forwarded_secure()`]
+    /// to determine whether a request is handled in a secure context.
+    ///
+    /// [`X-Forwarded-Proto`]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto
+    ///
+    /// To disable using any header for this purpose, set this value to `false`
+    /// or `None`. Deserialization semantics are identical to those of [`ip_header`].
+    ///
+    /// **(default: `None`)**
+    #[serde(deserialize_with = "crate::config::http_header::deserialize")]
+    pub proxy_proto_header: Option<Uncased<'static>>,
     /// Streaming read size limits. **(default: [`Limits::default()`])**
     pub limits: Limits,
     /// Directory to store temporary files in. **(default:
@@ -189,6 +204,7 @@ impl Config {
             max_blocking: 512,
             ident: Ident::default(),
             ip_header: Some(Uncased::from_borrowed("X-Real-IP")),
+            proxy_proto_header: None,
             limits: Limits::default(),
             temp_dir: std::env::temp_dir().into(),
             keep_alive: 5,
@@ -409,6 +425,11 @@ impl Config {
             None => launch_meta_!("IP header: {}", "disabled".paint(VAL))
         }
 
+        match self.proxy_proto_header.as_ref() {
+            Some(name) => launch_meta_!("Proxy-Proto header: {}", name.paint(VAL)),
+            None => launch_meta_!("Proxy-Proto header: {}", "disabled".paint(VAL))
+        }
+
         launch_meta_!("limits: {}", (&self.limits).paint(VAL));
         launch_meta_!("temp dir: {}", self.temp_dir.relative().display().paint(VAL));
         launch_meta_!("http/2: {}", (cfg!(feature = "http2").paint(VAL)));
@@ -513,6 +534,9 @@ impl Config {
     /// The stringy parameter name for setting/extracting [`Config::ip_header`].
     pub const IP_HEADER: &'static str = "ip_header";
 
+    /// The stringy parameter name for setting/extracting [`Config::proxy_proto_header`].
+    pub const PROXY_PROTO_HEADER: &'static str = "proxy_proto_header";
+
     /// The stringy parameter name for setting/extracting [`Config::limits`].
     pub const LIMITS: &'static str = "limits";
 
@@ -536,10 +560,9 @@ impl Config {
 
     /// An array of all of the stringy parameter names.
     pub const PARAMETERS: &'static [&'static str] = &[
-        Self::ADDRESS, Self::PORT, Self::WORKERS, Self::MAX_BLOCKING,
+        Self::ADDRESS, Self::PORT, Self::WORKERS, Self::MAX_BLOCKING, Self::KEEP_ALIVE,
-        Self::KEEP_ALIVE, Self::IDENT, Self::IP_HEADER, Self::LIMITS, Self::TLS,
+        Self::IDENT, Self::IP_HEADER, Self::PROXY_PROTO_HEADER, Self::LIMITS, Self::TLS,
-        Self::SECRET_KEY, Self::TEMP_DIR, Self::LOG_LEVEL, Self::SHUTDOWN,
+        Self::SECRET_KEY, Self::TEMP_DIR, Self::LOG_LEVEL, Self::SHUTDOWN, Self::CLI_COLORS,
-        Self::CLI_COLORS,
     ];
 }
 

core/lib/src/config/mod.rs

@@ -114,8 +114,8 @@
 mod ident;
 mod config;
 mod shutdown;
-mod ip_header;
 mod cli_colors;
+mod http_header;
 
 #[cfg(feature = "tls")]
 mod tls;

core/lib/src/cookies.rs

@@ -2,8 +2,8 @@ use std::fmt;
 
 use parking_lot::Mutex;
 
-use crate::Config;
 use crate::http::private::cookie;
+use crate::{Rocket, Orbit};
 
 #[doc(inline)]
 pub use self::cookie::{Cookie, SameSite, Iter};
@@ -154,17 +154,14 @@ pub use self::cookie::{Cookie, SameSite, Iter};
 pub struct CookieJar<'a> {
     jar: cookie::CookieJar,
     ops: Mutex<Vec<Op>>,
-    config: &'a Config,
+    pub(crate) state: CookieState<'a>,
 }
 
-impl<'a> Clone for CookieJar<'a> {
+#[derive(Copy, Clone)]
-    fn clone(&self) -> Self {
+pub(crate) struct CookieState<'a> {
-        CookieJar {
+    pub secure: bool,
-            jar: self.jar.clone(),
+    #[cfg_attr(not(feature = "secrets"), allow(unused))]
-            ops: Mutex::new(self.ops.lock().clone()),
+    pub config: &'a crate::Config,
-            config: self.config,
-        }
-    }
 }
 
 #[derive(Clone)]
@@ -173,22 +170,17 @@ enum Op {
     Remove(Cookie<'static>, bool),
 }
 
-impl Op {
-    fn cookie(&self) -> &Cookie<'static> {
-        match self {
-            Op::Add(c, _) | Op::Remove(c, _) => c
-        }
-    }
-}
-
 impl<'a> CookieJar<'a> {
-    #[inline(always)]
+    pub(crate) fn new(base: Option<cookie::CookieJar>, rocket: &'a Rocket<Orbit>) -> Self {
-    pub(crate) fn new(config: &'a Config) -> Self {
+        CookieJar {
-        CookieJar::from(cookie::CookieJar::new(), config)
+            jar: base.unwrap_or_default(),
-    }
+            ops: Mutex::new(Vec::new()),
-
+            state: CookieState {
-    pub(crate) fn from(jar: cookie::CookieJar, config: &'a Config) -> Self {
+                // This is updated dynamically when headers are received.
-        CookieJar { jar, config, ops: Mutex::new(Vec::new()) }
+                secure: rocket.config().tls_enabled(),
+                config: rocket.config(),
+            }
+        }
     }
 
     /// Returns a reference to the _original_ `Cookie` inside this container
@@ -236,7 +228,7 @@ impl<'a> CookieJar<'a> {
     #[cfg(feature = "secrets")]
     #[cfg_attr(nightly, doc(cfg(feature = "secrets")))]
     pub fn get_private(&self, name: &str) -> Option<Cookie<'static>> {
-        self.jar.private(&self.config.secret_key.key).get(name)
+        self.jar.private(&self.state.config.secret_key.key).get(name)
     }
 
     /// Returns a reference to the _original or pending_ `Cookie` inside this
@@ -287,7 +279,10 @@ impl<'a> CookieJar<'a> {
     ///    * `path`: `"/"`
     ///    * `SameSite`: `Strict`
     ///
-    /// Furthermore, if TLS is enabled, the `Secure` cookie flag is set.
+    /// Furthermore, if TLS is enabled or handled by a proxy (as determined by
+    /// [`Request::context_is_likely_secure()`]), the `Secure` cookie flag is set.
+    /// These defaults ensure maximum usability and security. For additional
+    /// security, you may wish to set the `secure` flag explicitly.
     ///
     /// # Example
     ///
@@ -309,7 +304,7 @@ impl<'a> CookieJar<'a> {
     /// ```
     pub fn add<C: Into<Cookie<'static>>>(&self, cookie: C) {
         let mut cookie = cookie.into();
-        Self::set_defaults(self.config, &mut cookie);
+        self.set_defaults(&mut cookie);
         self.ops.lock().push(Op::Add(cookie, false));
     }
 
@@ -327,9 +322,10 @@ impl<'a> CookieJar<'a> {
     ///    * `HttpOnly`: `true`
     ///    * `Expires`: 1 week from now
     ///
-    /// Furthermore, if TLS is enabled, the `Secure` cookie flag is set. These
+    /// Furthermore, if TLS is enabled or handled by a proxy (as determined by
-    /// defaults ensure maximum usability and security. For additional security,
+    /// [`Request::context_is_likely_secure()`]), the `Secure` cookie flag is set.
-    /// you may wish to set the `secure` flag.
+    /// These defaults ensure maximum usability and security. For additional
+    /// security, you may wish to set the `secure` flag explicitly.
     ///
     /// # Example
     ///
@@ -346,7 +342,7 @@ impl<'a> CookieJar<'a> {
     #[cfg_attr(nightly, doc(cfg(feature = "secrets")))]
     pub fn add_private<C: Into<Cookie<'static>>>(&self, cookie: C) {
         let mut cookie = cookie.into();
-        Self::set_private_defaults(self.config, &mut cookie);
+        self.set_private_defaults(&mut cookie);
         self.ops.lock().push(Op::Add(cookie, true));
     }
 
@@ -476,7 +472,7 @@ impl<'a> CookieJar<'a> {
                 Op::Add(c, false) => jar.add(c),
                 #[cfg(feature = "secrets")]
                 Op::Add(c, true) => {
-                    jar.private_mut(&self.config.secret_key.key).add(c);
+                    jar.private_mut(&self.state.config.secret_key.key).add(c);
                 }
                 Op::Remove(mut c, _) => {
                     if self.jar.get(c.name()).is_some() {
@@ -505,7 +501,7 @@ impl<'a> CookieJar<'a> {
     #[cfg_attr(nightly, doc(cfg(feature = "secrets")))]
     #[inline(always)]
     pub(crate) fn add_original_private(&mut self, cookie: Cookie<'static>) {
-        self.jar.private_mut(&self.config.secret_key.key).add_original(cookie);
+        self.jar.private_mut(&self.state.config.secret_key.key).add_original(cookie);
     }
 
     /// For each property mentioned below, this method checks if there is a
@@ -515,8 +511,9 @@ impl<'a> CookieJar<'a> {
     ///    * `path`: `"/"`
     ///    * `SameSite`: `Strict`
     ///
-    /// Furthermore, if TLS is enabled, the `Secure` cookie flag is set.
+    /// Furthermore, if TLS is enabled or handled by a proxy (as determined by
-    fn set_defaults(config: &Config, cookie: &mut Cookie<'static>) {
+    /// [`Request::context_is_likely_secure()`]), the `Secure` cookie flag is set.
+    fn set_defaults(&self, cookie: &mut Cookie<'static>) {
         if cookie.path().is_none() {
             cookie.set_path("/");
         }
@@ -525,7 +522,7 @@ impl<'a> CookieJar<'a> {
             cookie.set_same_site(SameSite::Strict);
         }
 
-        if cookie.secure().is_none() && config.tls_enabled() {
+        if cookie.secure().is_none() && self.state.secure {
             cookie.set_secure(true);
         }
     }
@@ -554,17 +551,12 @@ impl<'a> CookieJar<'a> {
     ///    * `HttpOnly`: `true`
     ///    * `Expires`: 1 week from now
     ///
-    /// Furthermore, if TLS is enabled, the `Secure` cookie flag is set.
+    /// Furthermore, if TLS is enabled or handled by a proxy (as determined by
+    /// [`Request::context_is_likely_secure()`]), the `Secure` cookie flag is set.
     #[cfg(feature = "secrets")]
     #[cfg_attr(nightly, doc(cfg(feature = "secrets")))]
-    fn set_private_defaults(config: &Config, cookie: &mut Cookie<'static>) {
+    fn set_private_defaults(&self, cookie: &mut Cookie<'static>) {
-        if cookie.path().is_none() {
+        self.set_defaults(cookie);
-            cookie.set_path("/");
-        }
-
-        if cookie.same_site().is_none() {
-            cookie.set_same_site(SameSite::Strict);
-        }
 
         if cookie.http_only().is_none() {
             cookie.set_http_only(true);
@@ -573,10 +565,6 @@ impl<'a> CookieJar<'a> {
         if cookie.expires().is_none() {
             cookie.set_expires(time::OffsetDateTime::now_utc() + time::Duration::weeks(1));
         }
-
-        if cookie.secure().is_none() && config.tls_enabled() {
-            cookie.set_secure(true);
-        }
     }
 }
 
@@ -593,5 +581,22 @@ impl fmt::Debug for CookieJar<'_> {
             .field("pending", &pending)
             .finish()
     }
-
+}
+
+impl<'a> Clone for CookieJar<'a> {
+    fn clone(&self) -> Self {
+        CookieJar {
+            jar: self.jar.clone(),
+            ops: Mutex::new(self.ops.lock().clone()),
+            state: self.state,
+        }
+    }
+}
+
+impl Op {
+    fn cookie(&self) -> &Cookie<'static> {
+        match self {
+            Op::Add(c, _) | Op::Remove(c, _) => c
+        }
+    }
 }

core/lib/src/local/asynchronous/response.rs

@@ -87,8 +87,11 @@ impl<'c> LocalResponse<'c> {
         let request: &'c Request<'c> = unsafe { &*(&*boxed_req as *const _) };
 
         async move {
+            // NOTE: The new `secure` cookie jar state will not reflect the last
+            // known value in `request.cookies()`. This is okay as new cookies
+            // should never be added to the resulting jar.
             let response: Response<'c> = f(request).await;
-            let mut cookies = CookieJar::new(request.rocket().config());
+            let mut cookies = CookieJar::new(None, request.rocket());
             for cookie in response.cookies() {
                 cookies.add_original(cookie.into_owned());
             }

core/lib/src/local/client.rs

@@ -181,9 +181,8 @@ macro_rules! pub_client_impl {
     /// ```
     #[inline(always)]
     pub fn cookies(&self) -> crate::http::CookieJar<'_> {
-        let config = &self.rocket().config();
         let jar = self._with_raw_cookies(|jar| jar.clone());
-        crate::http::CookieJar::from(jar, config)
+        crate::http::CookieJar::new(Some(jar), self.rocket())
     }
 
     req_method!($import, "GET", get, Method::Get);

core/lib/src/request/from_request.rs

@@ -6,7 +6,7 @@ use crate::{Request, Route};
 use crate::outcome::{self, Outcome::*};
 
 use crate::http::uri::{Host, Origin};
-use crate::http::{Status, ContentType, Accept, Method, CookieJar};
+use crate::http::{Status, ContentType, Accept, Method, ProxyProto, CookieJar};
 
 /// Type alias for the `Outcome` of a `FromRequest` conversion.
 pub type Outcome<S, E> = outcome::Outcome<S, (Status, E), Status>;
@@ -160,6 +160,12 @@ pub type Outcome<S, E> = outcome::Outcome<S, (Status, E), Status>;
 ///     via [`Request::client_ip()`]. If the client's IP address is not known,
 ///     the request is forwarded with a 500 Internal Server Error status.
 ///
+///   * **ProxyProto**
+///
+///     Extracts the protocol of the incoming request as a [`ProxyProto`] via
+///     [`Request::proxy_proto()`] (HTTP or HTTPS). If value of the header is
+///     not known, the request is forwarded with a 404 Not Found status.
+///
 ///   * **SocketAddr**
 ///
 ///     Extracts the remote address of the incoming request as a [`SocketAddr`]
@@ -470,6 +476,18 @@ impl<'r> FromRequest<'r> for IpAddr {
     }
 }
 
+#[crate::async_trait]
+impl<'r> FromRequest<'r> for ProxyProto<'r> {
+    type Error = std::convert::Infallible;
+
+    async fn from_request(request: &'r Request<'_>) -> Outcome<Self, Self::Error> {
+        match request.proxy_proto() {
+            Some(proto) => Success(proto),
+            None => Forward(Status::InternalServerError),
+        }
+    }
+}
+
 #[crate::async_trait]
 impl<'r> FromRequest<'r> for SocketAddr {
     type Error = Infallible;

core/lib/src/request/request.rs

@@ -13,9 +13,8 @@ use crate::request::{FromParam, FromSegments, FromRequest, Outcome};
 use crate::form::{self, ValueField, FromForm};
 use crate::data::Limits;
 
-use crate::http::{hyper, Method, Header, HeaderMap};
+use crate::http::{hyper, Method, Header, HeaderMap, ProxyProto};
 use crate::http::{ContentType, Accept, MediaType, CookieJar, Cookie};
-use crate::http::uncased::UncasedStr;
 use crate::http::private::Certificates;
 use crate::http::uri::{fmt::Path, Origin, Segments, Host, Authority};
 
@@ -97,7 +96,7 @@ impl<'r> Request<'r> {
             state: RequestState {
                 rocket,
                 route: Atomic::new(None),
-                cookies: CookieJar::new(rocket.config()),
+                cookies: CookieJar::new(None, rocket),
                 accept: InitCell::new(),
                 content_type: InitCell::new(),
                 cache: Arc::new(<TypeMap![Send + Sync]>::new()),
@@ -386,6 +385,85 @@ impl<'r> Request<'r> {
             })
     }
 
+    /// Returns the [`ProxyProto`] associated with the current request.
+    ///
+    /// The value is determined by inspecting the header named
+    /// [`proxy_proto_header`](crate::Config::proxy_proto_header), if
+    /// configured. If parameter isn't configured or the request doesn't contain
+    /// a header named as indicated, this method returns `None`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use rocket::http::{Header, ProxyProto};
+    ///
+    /// # let c = rocket::local::blocking::Client::debug_with(vec![]).unwrap();
+    /// # let req = c.get("/");
+    /// // By default, no `proxy_proto_header` is configured.
+    /// let req = req.header(Header::new("x-forwarded-proto", "https"));
+    /// assert_eq!(req.proxy_proto(), None);
+    ///
+    /// // We can configure one by setting the `proxy_proto_header` parameter.
+    /// // Here we set it to `x-forwarded-proto`, considered de-facto standard.
+    /// # let figment = rocket::figment::Figment::from(rocket::Config::debug_default());
+    /// let figment = figment.merge(("proxy_proto_header", "x-forwarded-proto"));
+    /// # let c = rocket::local::blocking::Client::debug(rocket::custom(figment)).unwrap();
+    /// # let req = c.get("/");
+    /// let req = req.header(Header::new("x-forwarded-proto", "https"));
+    /// assert_eq!(req.proxy_proto(), Some(ProxyProto::Https));
+    ///
+    /// # let req = c.get("/");
+    /// let req = req.header(Header::new("x-forwarded-proto", "http"));
+    /// assert_eq!(req.proxy_proto(), Some(ProxyProto::Http));
+    ///
+    /// # let req = c.get("/");
+    /// let req = req.header(Header::new("x-forwarded-proto", "xproto"));
+    /// assert_eq!(req.proxy_proto(), Some(ProxyProto::Unknown("xproto".into())));
+    /// ```
+    pub fn proxy_proto(&self) -> Option<ProxyProto<'_>> {
+        self.rocket()
+            .config
+            .proxy_proto_header
+            .as_ref()
+            .and_then(|header| self.headers().get_one(header.as_str()))
+            .map(ProxyProto::from)
+    }
+
+    /// Returns whether we are *likely* in a secure context.
+    ///
+    /// A request is in a "secure context" if it was initially sent over a
+    /// secure (TLS, via HTTPS) connection. If TLS is configured and enabled,
+    /// then the request is guaranteed to be in a secure context. Otherwise, if
+    /// [`Request::proxy_proto()`] evaluates to `Https`, then we are _likely_ to
+    /// be in a secure context. We say _likely_ because it is entirely possible
+    /// for the header to indicate that the connection is being proxied via
+    /// HTTPS while reality differs. As such, this value should not be trusted
+    /// when security is a concern.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use rocket::http::{Header, ProxyProto};
+    ///
+    /// # let client = rocket::local::blocking::Client::debug_with(vec![]).unwrap();
+    /// # let req = client.get("/");
+    /// // If TLS and proxy_proto are disabled, we are not in a secure context.
+    /// assert_eq!(req.context_is_likely_secure(), false);
+    ///
+    /// // Configuring proxy_proto and receiving a header value of `https` is
+    /// // interpreted as likely being in a secure context.
+    /// // Here we set it to `x-forwarded-proto`, considered de-facto standard.
+    /// # let figment = rocket::figment::Figment::from(rocket::Config::debug_default());
+    /// let figment = figment.merge(("proxy_proto_header", "x-forwarded-proto"));
+    /// # let c = rocket::local::blocking::Client::debug(rocket::custom(figment)).unwrap();
+    /// # let req = c.get("/");
+    /// let req = req.header(Header::new("x-forwarded-proto", "https"));
+    /// assert_eq!(req.context_is_likely_secure(), true);
+    /// ```
+    pub fn context_is_likely_secure(&self) -> bool {
+        self.cookies().state.secure
+    }
+
     /// Attempts to return the client's IP address by first inspecting the
     /// [`ip_header`](crate::Config::ip_header) and then using the remote
     /// connection's IP address. Note that the built-in `IpAddr` request guard
@@ -497,7 +575,7 @@ impl<'r> Request<'r> {
     #[inline]
     pub fn add_header<'h: 'r, H: Into<Header<'h>>>(&mut self, header: H) {
         let header = header.into();
-        self.bust_header_cache(header.name(), false);
+        self.bust_header_cache(&header, false);
         self.headers.add(header);
     }
 
@@ -526,7 +604,7 @@ impl<'r> Request<'r> {
     #[inline]
     pub fn replace_header<'h: 'r, H: Into<Header<'h>>>(&mut self, header: H) {
         let header = header.into();
-        self.bust_header_cache(header.name(), true);
+        self.bust_header_cache(&header, true);
         self.headers.replace(header);
     }
 
@@ -547,9 +625,9 @@ impl<'r> Request<'r> {
     /// ```
     #[inline]
     pub fn content_type(&self) -> Option<&ContentType> {
-        self.state.content_type.get_or_init(|| {
+        self.state.content_type
-            self.headers().get_one("Content-Type").and_then(|v| v.parse().ok())
+            .get_or_init(|| self.headers().get_one("Content-Type").and_then(|v| v.parse().ok()))
-        }).as_ref()
+            .as_ref()
     }
 
     /// Returns the Accept header of `self`. If the header is not present,
@@ -567,9 +645,9 @@ impl<'r> Request<'r> {
     /// ```
     #[inline]
     pub fn accept(&self) -> Option<&Accept> {
-        self.state.accept.get_or_init(|| {
+        self.state.accept
-            self.headers().get_one("Accept").and_then(|v| v.parse().ok())
+            .get_or_init(|| self.headers().get_one("Accept").and_then(|v| v.parse().ok()))
-        }).as_ref()
+            .as_ref()
     }
 
     /// Returns the media type "format" of the request.
@@ -925,15 +1003,19 @@ impl<'r> Request<'r> {
 #[doc(hidden)]
 impl<'r> Request<'r> {
     /// Resets the cached value (if any) for the header with name `name`.
-    fn bust_header_cache(&mut self, name: &UncasedStr, replace: bool) {
+    fn bust_header_cache(&mut self, header: &Header<'_>, replace: bool) {
-        if name == "Content-Type" {
+        if header.name() == "Content-Type" {
             if self.content_type().is_none() || replace {
                 self.state.content_type = InitCell::new();
             }
-        } else if name == "Accept" {
+        } else if header.name() == "Accept" {
             if self.accept().is_none() || replace {
                 self.state.accept = InitCell::new();
             }
+        } else if Some(header.name()) == self.rocket().config.proxy_proto_header.as_deref() {
+            if !self.cookies().state.secure || replace {
+                self.cookies_mut().state.secure |= ProxyProto::from(header.value()).is_https();
+            }
         }
     }
 

core/lib/tests/config-proxy-proto-header.rs

@@ -0,0 +1,118 @@
+use rocket::http::ProxyProto;
+
+#[macro_use]
+extern crate rocket;
+
+#[get("/")]
+fn inspect_proto(proto: Option<ProxyProto>) -> String {
+    proto
+        .map(|proto| match proto {
+            ProxyProto::Http => "http".to_owned(),
+            ProxyProto::Https => "https".to_owned(),
+            ProxyProto::Unknown(s) => s.to_string(),
+        })
+        .unwrap_or("<none>".to_owned())
+}
+
+mod tests {
+    use rocket::{Rocket, Build, Route};
+    use rocket::http::Header;
+    use rocket::local::blocking::Client;
+    use rocket::figment::Figment;
+
+    fn routes() -> Vec<Route> {
+        routes![super::inspect_proto]
+    }
+
+    fn rocket_with_proto_header(header: Option<&'static str>) -> Rocket<Build> {
+        let mut config = rocket::Config::debug_default();
+        config.proxy_proto_header = header.map(|h| h.into());
+        rocket::custom(config).mount("/", routes())
+    }
+
+    #[test]
+    fn check_proxy_proto_header_works() {
+        let rocket = rocket_with_proto_header(Some("X-Url-Scheme"));
+        let client = Client::debug(rocket).unwrap();
+        let response = client.get("/")
+            .header(Header::new("X-Forwarded-Proto", "https"))
+            .header(Header::new("X-Url-Scheme", "http"))
+            .dispatch();
+
+        assert_eq!(response.into_string().unwrap(), "http");
+
+        let response = client.get("/")
+            .header(Header::new("X-Url-Scheme", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string().unwrap(), "https");
+
+        let response = client.get("/").dispatch();
+        assert_eq!(response.into_string().unwrap(), "<none>");
+    }
+
+    #[test]
+    fn check_proxy_proto_header_works_again() {
+        let client = Client::debug(rocket_with_proto_header(Some("x-url-scheme"))).unwrap();
+        let response = client
+            .get("/")
+            .header(Header::new("X-Url-Scheme", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string().unwrap(), "https");
+
+        let config = Figment::from(rocket::Config::debug_default())
+            .merge(("proxy_proto_header", "x-url-scheme"));
+
+        let client = Client::debug(rocket::custom(config).mount("/", routes())).unwrap();
+        let response = client
+            .get("/")
+            .header(Header::new("X-url-Scheme", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string().unwrap(), "https");
+    }
+
+    #[test]
+    fn check_default_proxy_proto_header_works() {
+        let client = Client::debug_with(routes()).unwrap();
+        let response = client
+            .get("/")
+            .header(Header::new("X-Forwarded-Proto", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string(), Some("<none>".into()));
+    }
+
+    #[test]
+    fn check_no_proxy_proto_header_works() {
+        let client = Client::debug(rocket_with_proto_header(None)).unwrap();
+        let response = client.get("/")
+            .header(Header::new("X-Forwarded-Proto", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string(), Some("<none>".into()));
+
+        let config =
+            Figment::from(rocket::Config::debug_default()).merge(("proxy_proto_header", false));
+
+        let client = Client::debug(rocket::custom(config).mount("/", routes())).unwrap();
+        let response = client
+            .get("/")
+            .header(Header::new("X-Forwarded-Proto", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string(), Some("<none>".into()));
+
+        let config = Figment::from(rocket::Config::debug_default())
+            .merge(("proxy_proto_header", "x-forwarded-proto"));
+
+        let client = Client::debug(rocket::custom(config).mount("/", routes())).unwrap();
+        let response = client
+            .get("/")
+            .header(Header::new("x-Forwarded-Proto", "https"))
+            .dispatch();
+
+        assert_eq!(response.into_string(), Some("https".into()));
+    }
+}

site/guide/9-configuration.md

@@ -17,28 +17,31 @@ is configured with. This means that no matter which configuration provider
 Rocket is asked to use, it must be able to read the following configuration
 values:
 
-| key             | kind              | description                                     | debug/release default   |
+| key                  | kind              | description                                     | debug/release default   |
-|-----------------|-------------------|-------------------------------------------------|-------------------------|
+|----------------------|-------------------|-------------------------------------------------|-------------------------|
-| `address`       | `IpAddr`          | IP address to serve on                          | `127.0.0.1`             |
+| `address`            | `IpAddr`          | IP address to serve on.                         | `127.0.0.1`             |
-| `port`          | `u16`             | Port to serve on.                               | `8000`                  |
+| `port`               | `u16`             | Port to serve on.                               | `8000`                  |
-| `workers`*      | `usize`           | Number of threads to use for executing futures. | cpu core count          |
+| `workers`*           | `usize`           | Number of threads to use for executing futures. | cpu core count          |
-| `max_blocking`* | `usize`           | Limit on threads to start for blocking tasks.   | `512`                   |
+| `max_blocking`*      | `usize`           | Limit on threads to start for blocking tasks.   | `512`                   |
-| `ident`         | `string`, `false` | If and how to identify via the `Server` header. | `"Rocket"`              |
+| `ident`              | `string`, `false` | If and how to identify via the `Server` header. | `"Rocket"`              |
-| `ip_header`     | `string`, `false` | IP header to inspect to get [client's real IP]. | `"X-Real-IP"`           |
+| `ip_header`          | `string`, `false` | IP header to inspect to get [client's real IP]. | `"X-Real-IP"`           |
-| `keep_alive`    | `u32`             | Keep-alive timeout seconds; disabled when `0`.  | `5`                     |
+| `proxy_proto_header` | `string`, `false` | Header identifying [client to proxy protocol].  | `None`                  |
-| `log_level`     | [`LogLevel`]      | Max level to log. (off/normal/debug/critical)   | `normal`/`critical`     |
+| `keep_alive`         | `u32`             | Keep-alive timeout seconds; disabled when `0`.  | `5`                     |
-| `cli_colors`    | [`CliColors`]     | Whether to use colors and emoji when logging.   | `"auto"`                |
+| `log_level`          | [`LogLevel`]      | Max level to log. (off/normal/debug/critical)   | `normal`/`critical`     |
-| `secret_key`    | [`SecretKey`]     | Secret key for signing and encrypting values.   | `None`                  |
+| `cli_colors`         | [`CliColors`]     | Whether to use colors and emoji when logging.   | `"auto"`                |
-| `tls`           | [`TlsConfig`]     | TLS configuration, if any.                      | `None`                  |
+| `secret_key`         | [`SecretKey`]     | Secret key for signing and encrypting values.   | `None`                  |
-| `limits`        | [`Limits`]        | Streaming read size limits.                     | [`Limits::default()`]   |
+| `tls`                | [`TlsConfig`]     | TLS configuration, if any.                      | `None`                  |
-| `limits.$name`  | `&str`/`uint`     | Read limit for `$name`.                         | form = "32KiB"          |
+| `limits`             | [`Limits`]        | Streaming read size limits.                     | [`Limits::default()`]   |
-| `ctrlc`         | `bool`            | Whether `ctrl-c` initiates a server shutdown.   | `true`                  |
+| `limits.$name`       | `&str`/`uint`     | Read limit for `$name`.                         | form = "32KiB"          |
-| `shutdown`*     | [`Shutdown`]      | Graceful shutdown configuration.                | [`Shutdown::default()`] |
+| `ctrlc`              | `bool`            | Whether `ctrl-c` initiates a server shutdown.   | `true`                  |
+| `shutdown`*          | [`Shutdown`]      | Graceful shutdown configuration.                | [`Shutdown::default()`] |
+
 
 <small>* Note: the `workers`, `max_blocking`, and `shutdown.force` configuration
 parameters are only read from the [default provider](#default-provider).</small>
 
 [client's real IP]: @api/rocket/request/struct.Request.html#method.real_ip
+[client to proxy protocol]: @api/rocket/request/struct.Request.html#method.proxy_proto
 
 ### Profiles
 
@@ -130,6 +133,7 @@ port = 9001
 [release]
 port = 9999
 ip_header = false
+proxy_proto_header = "X-Forwarded-Proto"
 # NOTE: Don't (!) use this key! Generate your own and keep it private!
 #       e.g. via `head -c64 /dev/urandom | base64`
 secret_key = "hPrYyЭRiMyµ5sBB1π+CMæ1køFsåqKvBiQJxBVHQk="
@@ -148,7 +152,8 @@ workers = 16
 max_blocking = 512
 keep_alive = 5
 ident = "Rocket"
-ip_header = "X-Real-IP" # set to `false` to disable
+ip_header = "X-Real-IP" # set to `false` or `None` to disable
+proxy_proto_header = `false` # set to `false` or `None` to disable
 log_level = "normal"
 temp_dir = "/tmp"
 cli_colors = true
@@ -358,6 +363,25 @@ mutual TLS.
 
 [`mtls::Certificate`]: @api/rocket/mtls/struct.Certificate.html
 
+### Proxied TLS
+
+If Rocket is running behind a reverse proxy that terminates TLS, it is useful to
+know whether the original connection was made securely. Therefore, Rocket offers
+the option to configure a `proxy_proto_header` that is used to determine if the
+request is handled in a secure context. The outcome is available via
+[`Request::context_is_likely_secure()`] and used to set cookies' secure flag by
+default. To enable this behaviour, configure the header as set by your reverse
+proxy. For example:
+
+```toml,ignore
+proxy_proto_header = 'X-Forwarded-Proto'
+```
+
+Note that this only sets the cookies' secure flag when not configured
+explicitly. This setting also provides the [request guard `ProxyProto`].
+
+[`ProxyProto`]: @api/rocket/request/trait.FromRequest.html#impl-FromRequest%3C'r%3E-for-%26ProxyProto
+
 ### Workers
 
 The `workers` parameter sets the number of threads used for parallel task