feat(cors): Support private network access (#11523)

The Access-Control-Request-Private-Network header in crossing-origin pre-light requests is supported through adding a new parameter private_network which determines whether the Access-Control-Allow-Private-Network header should be carried in the response headers with true as the value.

FTI-5258

changelog/unreleased/kong/11523.yml

@@ -0,0 +1,5 @@
+"message": "**CORS**: Support the `Access-Control-Request-Private-Network` header in crossing-origin pre-light requests"
+"type": "feature"
+"scope": "Plugin"
+"jiras":
+- "FTI-5258"

kong/clustering/compat/removed_fields.lua

@@ -93,4 +93,10 @@ return {
       "sync_rate",
     },
   },
+
+  [3005000000] = {
+    cors = {
+      "private_network",
+    }
+  }
 }

kong/plugins/cors/handler.lua

@@ -228,6 +228,11 @@ function CorsHandler:access(conf)
     set_header("Access-Control-Max-Age", tostring(conf.max_age))
   end
 
+  if conf.private_network and
+    kong.request.get_header("Access-Control-Request-Private-Network") == 'true' then
+      set_header("Access-Control-Allow-Private-Network", 'true')
+  end
+
   return kong.response.exit(HTTP_OK)
 end
 

kong/plugins/cors/schema.lua

@@ -46,6 +46,7 @@ return {
           }, }, },
           { max_age = { description = "Indicates how long the results of the preflight request can be cached, in `seconds`.", type = "number" }, },
           { credentials = { description = "Flag to determine whether the `Access-Control-Allow-Credentials` header should be sent with `true` as the value.", type = "boolean", required = true, default = false }, },
+          { private_network = { description = "Flag to determine whether the `Access-Control-Allow-Private-Network` header should be sent with `true` as the value.", type = "boolean", required = true, default = false }, },
           { preflight_continue = { description = "A boolean value that instructs the plugin to proxy the `OPTIONS` preflight request to the Upstream service.", type = "boolean", required = true, default = false }, },
     }, }, },
   },

spec/02-integration/09-hybrid_mode/09-config-compat_spec.lua

@@ -35,11 +35,11 @@ end
 local function get_plugin(node_id, node_version, name)
   local res, err = cluster_client({ id = node_id, version = node_version })
   assert.is_nil(err)
-  assert.is_table(res and res.config and res.config.plugins,
+  assert.is_table(res and res.config_table and res.config_table.plugins,
                   "invalid response from clustering client")
 
   local plugin
-  for _, p in ipairs(res.config.plugins) do
+  for _, p in ipairs(res.config_table.plugins or {}) do
     if p.name == name then
       plugin = p
       break
@@ -108,7 +108,7 @@ describe("CP/DP config compat transformations #" .. strategy, function()
   end)
 
   describe("plugin config fields", function()
-    local rate_limit, opentelemetry, zipkin
+    local rate_limit, opentelemetry, zipkin, cors
 
     lazy_setup(function()
       rate_limit = admin.plugins:insert {
@@ -125,59 +125,75 @@ describe("CP/DP config compat transformations #" .. strategy, function()
           -- ]]
         },
       }
+
+      cors = admin.plugins:insert {
+        name = "cors",
+        enabled = true,
+        config = {
+          -- [[ new fields 3.5.0
+          private_network = false
+          -- ]]
+        }
+      }
     end)
 
     lazy_teardown(function()
       admin.plugins:remove({ id = rate_limit.id })
     end)
 
-    it("removes new fields before sending them to older DP nodes", function()
-      local id = utils.uuid()
-      local plugin = get_plugin(id, "3.0.0", rate_limit.name)
+    local function do_assert(node_id, node_version, expected_entity)
+      local plugin = get_plugin(node_id, node_version, expected_entity.name)
+      assert.same(expected_entity.config, plugin.config)
+      assert.equals(CLUSTERING_SYNC_STATUS.NORMAL, get_sync_status(node_id))
+    end
 
+    it("removes new fields before sending them to older DP nodes", function()
       --[[
         For 3.0.x
         should not have: error_code, error_message, sync_rate
       --]]
-      local expected = utils.cycle_aware_deep_copy(rate_limit.config)
-      expected.error_code = nil
-      expected.error_message = nil
-      expected.sync_rate = nil
-      assert.same(expected, plugin.config)
-      assert.equals(CLUSTERING_SYNC_STATUS.NORMAL, get_sync_status(id))
+      local expected = utils.cycle_aware_deep_copy(rate_limit)
+      expected.config.error_code = nil
+      expected.config.error_message = nil
+      expected.config.sync_rate = nil
+      do_assert(utils.uuid(), "3.0.0", expected)
 
 
       --[[
         For 3.2.x
         should have: error_code, error_message
         should not have: sync_rate
       --]]
-      id = utils.uuid()
-      plugin = get_plugin(id, "3.2.0", rate_limit.name)
-      expected = utils.cycle_aware_deep_copy(rate_limit.config)
-      expected.sync_rate = nil
-      assert.same(expected, plugin.config)
-      assert.equals(CLUSTERING_SYNC_STATUS.NORMAL, get_sync_status(id))
+      expected = utils.cycle_aware_deep_copy(rate_limit)
+      expected.config.sync_rate = nil
+      do_assert(utils.uuid(), "3.2.0", expected)
 
 
       --[[
         For 3.3.x,
         should have: error_code, error_message
         should not have: sync_rate
       --]]
-      id = utils.uuid()
-      plugin = get_plugin(id, "3.3.0", rate_limit.name)
-      expected = utils.cycle_aware_deep_copy(rate_limit.config)
-      expected.sync_rate = nil
-      assert.same(expected, plugin.config)
-      assert.equals(CLUSTERING_SYNC_STATUS.NORMAL, get_sync_status(id))
+      expected = utils.cycle_aware_deep_copy(rate_limit)
+      expected.config.sync_rate = nil
+      do_assert(utils.uuid(), "3.3.0", expected)
     end)
 
     it("does not remove fields from DP nodes that are already compatible", function()
-      local id = utils.uuid()
-      local plugin = get_plugin(id, "3.4.0", rate_limit.name)
-      assert.same(rate_limit.config, plugin.config)
-      assert.equals(CLUSTERING_SYNC_STATUS.NORMAL, get_sync_status(id))
+      do_assert(utils.uuid(), "3.4.0", rate_limit)
+    end)
+
+    describe("compatibility test for cors plugin", function()
+      it("removes `config.private_network` before sending them to older(less than 3.5.0.0) DP nodes", function()
+        assert.not_nil(cors.config.private_network)
+        local expected_cors = utils.cycle_aware_deep_copy(cors)
+        expected_cors.config.private_network = nil
+        do_assert(utils.uuid(), "3.4.0", expected_cors)
+      end)
+
+      it("does not remove `config.private_network` from DP nodes that are already compatible", function()
+        do_assert(utils.uuid(), "3.5.0", cors)
+      end)
     end)
 
     describe("compatibility tests for opentelemetry plugin", function()

spec/03-plugins/13-cors/01-access_spec.lua

@@ -283,6 +283,10 @@ for _, strategy in helpers.each_strategy() do
         hosts = { "cors12.com" },
       })
 
+      local route13 = bp.routes:insert({
+        hosts = { "cors13.com" },
+      })
+
       local mock_upstream = bp.services:insert {
         host = helpers.mock_upstream_hostname,
         port = helpers.mock_upstream_port,
@@ -437,6 +441,16 @@ for _, strategy in helpers.each_strategy() do
         }
       }
 
+      bp.plugins:insert {
+        name = "cors",
+        route = { id = route13.id },
+        config = {
+          preflight_continue = false,
+          private_network = true,
+          origins = { 'allowed-domain.test' }
+        }
+      }
+
       bp.plugins:insert {
         name = "cors",
         route = { id = route_timeout.id },
@@ -705,6 +719,20 @@ for _, strategy in helpers.each_strategy() do
         assert.res_status(200, res)
         assert.is_nil(res.headers["Access-Control-Allow-Origin"])
       end)
+
+      it("support private-network", function()
+        local res = assert(proxy_client:send {
+          method  = "OPTIONS",
+          headers = {
+            ["Host"]   = "cors13.com",
+            ["Origin"] = "allowed-domain.test",
+            ["Access-Control-Request-Private-Network"] = "true",
+            ["Access-Control-Request-Method"] = "PUT",
+          }
+        })
+        assert.res_status(200, res)
+        assert.equal("true", res.headers["Access-Control-Allow-Private-Network"])
+      end)
     end)
 
     describe("HTTP method: others", function()