Oauth2 resource param

api/envoy/extensions/filters/http/oauth2/v3alpha/oauth.proto

@@ -41,7 +41,7 @@ message OAuth2Credentials {
 
 // OAuth config
 //
-// [#next-free-field: 10]
+// [#next-free-field: 11]
 message OAuth2Config {
   // Endpoint on the authorization server to retrieve the access token from.
   config.core.v3.HttpUri token_endpoint = 1;
@@ -76,6 +76,10 @@ message OAuth2Config {
   // defaults to "user" scope.
   // OAuth RFC https://tools.ietf.org/html/rfc6749#section-3.3
   repeated string auth_scopes = 9;
+
+  // Optional resource parameter for authorization request
+  // RFC: https://tools.ietf.org/html/rfc8707
+  repeated string resources = 10;
 }
 
 // Filter config.

docs/root/configuration/http/http_filters/oauth2_filter.rst

@@ -76,6 +76,10 @@ The following is an example configuring the filter.
     - user
     - openid
     - email
+    # (Optional): set resource parameter for Authorization request
+    resources:
+    - oauth2-resource
+    - http://example.com
 
 Below is a complete code example of how we employ the filter as one of
 :ref:`HttpConnectionManager HTTP filters
@@ -124,6 +128,10 @@ Below is a complete code example of how we employ the filter as one of
                 - user
                 - openid
                 - email
+                # (Optional): set resource parameter for Authorization request
+                resources:
+                - oauth2-resource
+                - http://example.com
           - name: envoy.router
           tracing: {}
           codec_type: "AUTO"

source/extensions/filters/http/oauth2/filter.cc

@@ -93,6 +93,16 @@ authScopesList(const Protobuf::RepeatedPtrField<std::string>& auth_scopes_protos
   return scopes;
 }
 
+// Transforms the proto list into encoded resource params
+// Takes care of percentage encoding http and https is needed
+std::string encodeResourceList(const Protobuf::RepeatedPtrField<std::string>& resources_protos) {
+  std::string result = "";
+  for (const auto& resource : resources_protos) {
+    result += "&resource=" + Http::Utility::PercentEncoding::encode(resource, ":/=&? ");
+  }
+  return result;
+}
+
 // Sets the auth token as the Bearer token in the authorization header.
 void setBearerToken(Http::RequestHeaderMap& headers, const std::string& token) {
   headers.setInline(authorization_handle.handle(), absl::StrCat("Bearer ", token));
@@ -112,6 +122,7 @@ FilterConfig::FilterConfig(
       stats_(FilterConfig::generateStats(stats_prefix, scope)),
       encoded_auth_scopes_(Http::Utility::PercentEncoding::encode(
           absl::StrJoin(authScopesList(proto_config.auth_scopes()), " "), ":/=&? ")),
+      encoded_resources_(encodeResourceList(proto_config.resources())),
       forward_bearer_token_(proto_config.forward_bearer_token()),
       pass_through_header_matchers_(headerMatchers(proto_config.pass_through_matcher())) {
   if (!cluster_manager.clusters().hasCluster(oauth_token_endpoint_.cluster())) {
@@ -300,7 +311,10 @@ Http::FilterHeadersStatus OAuth2Filter::decodeHeaders(Http::RequestHeaderMap& he
     const std::string new_url = fmt::format(
         AuthorizationEndpointFormat, config_->authorizationEndpoint(), config_->clientId(),
         config_->encodedAuthScopes(), escaped_redirect_uri, escaped_state);
-    response_headers->setLocation(new_url);
+
+    const std::string& resource_param = config_->encodedResources();
+
+    response_headers->setLocation(new_url + resource_param);
     decoder_callbacks_->encodeHeaders(std::move(response_headers), true, REDIRECT_FOR_CREDENTIALS);
 
     config_->stats().oauth_unauthorized_rq_.inc();

source/extensions/filters/http/oauth2/filter.h

@@ -124,6 +124,7 @@ class FilterConfig {
   std::string tokenSecret() const { return secret_reader_->tokenSecret(); }
   FilterStats& stats() { return stats_; }
   const std::string& encodedAuthScopes() const { return encoded_auth_scopes_; }
+  const std::string& encodedResources() const { return encoded_resources_; }
 
 private:
   static FilterStats generateStats(const std::string& prefix, Stats::Scope& scope);
@@ -137,6 +138,7 @@ class FilterConfig {
   std::shared_ptr<SecretReader> secret_reader_;
   FilterStats stats_;
   const std::string encoded_auth_scopes_;
+  const std::string encoded_resources_;
   const bool forward_bearer_token_ : 1;
   const std::vector<Http::HeaderUtility::HeaderData> pass_through_header_matchers_;
 };

test/extensions/filters/http/oauth2/config_test.cc

@@ -51,6 +51,10 @@ void expectInvalidSecretConfig(const std::string& failed_secret_name,
   - user
   - openid
   - email
+  resources:
+  - oauth2-resource
+  - http://example.com
+  - https://example.com
     )EOF";
 
   OAuth2Config factory;
@@ -95,6 +99,10 @@ TEST(ConfigTest, CreateFilter) {
   - user
   - openid
   - email
+  resources:
+  - oauth2-resource
+  - http://example.com
+  - https://example.com
     )EOF";
 
   OAuth2Config factory;

test/extensions/filters/http/oauth2/filter_test.cc

@@ -109,6 +109,9 @@ class OAuth2Test : public testing::Test {
     p.add_auth_scopes("user");
     p.add_auth_scopes("openid");
     p.add_auth_scopes("email");
+    p.add_resources("oauth2-resource");
+    p.add_resources("http://example.com");
+    p.add_resources("https://example.com");
     auto* matcher = p.add_pass_through_matcher();
     matcher->set_name(":method");
     matcher->set_exact_match("OPTIONS");
@@ -197,6 +200,9 @@ TEST_F(OAuth2Test, DefaultAuthScope) {
   // Auth_scopes was not set, should return default value.
   EXPECT_EQ(test_config_->encodedAuthScopes(), TEST_DEFAULT_SCOPE);
 
+  // resource is optional
+  EXPECT_EQ(test_config_->encodedResources(), "");
+
   // Recreate the filter with current config and test if the scope was added
   // as a query parameter in response headers.
   init(test_config_);
@@ -324,7 +330,9 @@ TEST_F(OAuth2Test, OAuthErrorNonOAuthHttpCallback) {
            TEST_CLIENT_ID + "&scope=" + TEST_ENCODED_AUTH_SCOPES +
            "&response_type=code&"
            "redirect_uri=http%3A%2F%2Ftraffic.example.com%2F"
-           "_oauth&state=http%3A%2F%2Ftraffic.example.com%2Fnot%2F_oauth"},
+           "_oauth&state=http%3A%2F%2Ftraffic.example.com%2Fnot%2F_oauth"
+           "&resource=oauth2-resource&resource=http%3A%2F%2Fexample.com"
+           "&resource=https%3A%2F%2Fexample.com"},
   };
 
   // explicitly tell the validator to fail the validation
@@ -634,7 +642,9 @@ TEST_F(OAuth2Test, OAuthTestFullFlowPostWithParameters) {
            "&response_type=code&"
            "redirect_uri=https%3A%2F%2Ftraffic.example.com%2F"
            "_oauth&state=https%3A%2F%2Ftraffic.example.com%2Ftest%"
-           "3Fname%3Dadmin%26level%3Dtrace"},
+           "3Fname%3Dadmin%26level%3Dtrace"
+           "&resource=oauth2-resource&resource=http%3A%2F%2Fexample.com"
+           "&resource=https%3A%2F%2Fexample.com"},
   };
 
   // Fail the validation to trigger the OAuth flow.

test/extensions/filters/http/oauth2/oauth_integration_test.cc

@@ -62,6 +62,10 @@ name: oauth
     - user
     - openid
     - email
+    resources:
+    - oauth2-resource
+    - http://example.com
+    - https://example.com
 )EOF");
 
     // Add the OAuth cluster.