config: Add TRUSTPUB_AUDIENCE setting

This defaults to the domain name (crates.io / staging.crates.io) and controls the expected `aud` claim of the OIDC JWT in the Trusted Publishing token exchange.

Author: Turbo87

src/config/server.rs

@@ -87,6 +87,10 @@ pub struct Server {
     pub html_render_cache_max_capacity: u64,
 
     pub content_security_policy: Option<HeaderValue>,
+
+    /// The expected audience claim (`aud`) for the Trusted Publishing
+    /// token exchange.
+    pub trustpub_audience: String,
 }
 
 impl Server {
@@ -186,6 +190,9 @@ impl Server {
                 .unwrap_or_default()
         );
 
+        let domain_name = dotenvy::var("DOMAIN_NAME").unwrap_or_else(|_| "crates.io".into());
+        let trustpub_audience = var("TRUSTPUB_AUDIENCE")?.unwrap_or_else(|| domain_name.clone());
+
         Ok(Server {
             db: DatabasePools::full_from_environment(&base)?,
             storage,
@@ -210,7 +217,7 @@ impl Server {
             page_offset_ua_blocklist,
             page_offset_cidr_blocklist,
             excluded_crate_names,
-            domain_name: dotenvy::var("DOMAIN_NAME").unwrap_or_else(|_| "crates.io".into()),
+            domain_name,
             allowed_origins,
             downloads_persist_interval: var_parsed("DOWNLOADS_PERSIST_INTERVAL_MS")?
                 .map(Duration::from_millis)
@@ -233,6 +240,7 @@ impl Server {
             og_image_base_url: var_parsed("OG_IMAGE_BASE_URL")?,
             html_render_cache_max_capacity: var_parsed("HTML_RENDER_CACHE_CAP")?.unwrap_or(1024),
             content_security_policy: Some(content_security_policy.parse()?),
+            trustpub_audience,
         })
     }
 }

src/tests/util/test_app.rs

@@ -17,6 +17,7 @@ use crates_io_index::testing::UpstreamIndex;
 use crates_io_index::{Credentials, RepositoryConfig};
 use crates_io_team_repo::MockTeamRepo;
 use crates_io_test_db::TestDatabase;
+use crates_io_trustpub::github::test_helpers::AUDIENCE;
 use crates_io_worker::Runner;
 use diesel_async::AsyncPgConnection;
 use futures_util::TryStreamExt;
@@ -491,6 +492,7 @@ fn simple_config() -> config::Server {
         og_image_base_url: None,
         html_render_cache_max_capacity: 1024,
         content_security_policy: None,
+        trustpub_audience: AUDIENCE.to_string(),
     }
 }