Obtain allowed origin list from the environment

This adapts the scheme added in #2627. When operating behind
CloudFront, the Host received by nginx is the Heroku instance and does
not match the user facing crates.io origin. Therefore it is necessary to
obtain a list of allowed origins at boot time.

If this header is not set, the server will panic and will not boot.

Author: jtgeibel

.env.sample

@@ -3,6 +3,10 @@
 # `postgres://postgres@localhost/cargo_registry`.
 export DATABASE_URL=
 
+# Allowed origins - any origins for which you want to allow browser
+# access to authenticated endpoints.
+export WEB_ALLOWED_ORIGINS=http://localhost:8888,http://localhost:4200
+
 # If you are running a mirror of crates.io, uncomment this line.
 # export MIRROR=1
 

src/config.rs

@@ -17,6 +17,7 @@ pub struct Config {
     pub publish_rate_limit: PublishRateLimit,
     pub blocked_traffic: Vec<(String, Vec<String>)>,
     pub domain_name: String,
+    pub allowed_origins: Vec<String>,
 }
 
 impl Default for Config {
@@ -121,6 +122,7 @@ impl Default for Config {
                 }
             }
         };
+        let allowed_origins = env("WEB_ALLOWED_ORIGINS").split(',').map(ToString::to_string).collect();
         Config {
             uploader,
             session_key: env("SESSION_KEY"),
@@ -136,6 +138,7 @@ impl Default for Config {
             publish_rate_limit: Default::default(),
             blocked_traffic: blocked_traffic(),
             domain_name: domain_name(),
+            allowed_origins,
         }
     }
 }

src/controllers/util.rs

@@ -6,7 +6,6 @@ use crate::models::{ApiToken, User};
 use crate::util::errors::{
     forbidden, internal, AppError, AppResult, ChainError, InsecurelyGeneratedTokenRevoked,
 };
-use conduit::Host;
 
 #[derive(Debug)]
 pub struct AuthenticatedUser {
@@ -36,32 +35,16 @@ impl AuthenticatedUser {
 // be: https://crates.io in production, or http://localhost:port/ in development.
 fn verify_origin(req: &dyn RequestExt) -> AppResult<()> {
     let headers = req.headers();
-    // If x-forwarded-host and -proto are present, trust those to tell us what the proto and host
-    // are; otherwise (in local dev) trust the Host header and the scheme.
-    let forwarded_host = headers.get("x-forwarded-host");
-    let forwarded_proto = headers.get("x-forwarded-proto");
-    let expected_origin = match (forwarded_host, forwarded_proto) {
-        (Some(host), Some(proto)) => format!(
-            "{}://{}",
-            proto.to_str().unwrap_or_default(),
-            host.to_str().unwrap_or_default()
-        ),
-        // For the default case we assume HTTP, because we know we're not serving behind a reverse
-        // proxy, and we also know that crates by itself doesn't serve HTTPS.
-        _ => match req.host() {
-            Host::Name(a) => format!("http://{}", a),
-            Host::Socket(a) => format!("http://{}", a.to_string()),
-        },
-    };
+    let allowed_origins = req.app().config.allowed_origins.iter().map(|s| &**s).collect::<Vec<_>>();
 
     let bad_origin = headers
         .get_all(header::ORIGIN)
         .iter()
-        .find(|h| h.to_str().unwrap_or_default() != expected_origin);
+        .find(|h| !allowed_origins.contains(&h.to_str().unwrap_or_default()));
     if let Some(bad_origin) = bad_origin {
         let error_message = format!(
-            "only same-origin requests can be authenticated. expected {}, got {:?}",
-            expected_origin, bad_origin
+            "only same-origin requests can be authenticated. got {:?}",
+            bad_origin
         );
         return Err(internal(&error_message))
             .chain_error(|| Box::new(forbidden()) as Box<dyn AppError>);

src/tests/all.rs

@@ -145,6 +145,7 @@ fn simple_config() -> Config {
         publish_rate_limit: Default::default(),
         blocked_traffic: Default::default(),
         domain_name: "crates.io".into(),
+        allowed_origins: Vec::new(),
     }
 }