controlplane: only add listener virtual domains for addresses matching the current TLS domain (#1823)

internal/controlplane/luascripts/fix-misdirected.lua

@@ -0,0 +1,23 @@
+function envoy_on_request(request_handle)
+    local headers = request_handle:headers()
+    local dynamic_meta = request_handle:streamInfo():dynamicMetadata()
+
+    local authority = headers:get(":authority")
+
+    -- store the authority header in the metadata so we can retrieve it in the response
+    dynamic_meta:set("envoy.filters.http.lua", "request.authority", authority)
+end
+
+function envoy_on_response(response_handle)
+    local headers = response_handle:headers()
+    local dynamic_meta = response_handle:streamInfo():dynamicMetadata()
+
+    local authority =
+        dynamic_meta:get("envoy.filters.http.lua")["request.authority"]
+
+    -- if we got a 404 (no route found) and the authority header doens't match
+    -- assume we've coalesced http/2 connections and return a 421
+    if headers:get(":status") == "404" and authority ~= "%s" then
+        headers:replace(":status", "421")
+    end
+end

internal/controlplane/xds_listeners.go

@@ -2,6 +2,7 @@ package controlplane
 
 import (
 	"encoding/base64"
+	"fmt"
 	"net"
 	"net/url"
 	"sort"
@@ -66,7 +67,7 @@ func (srv *Server) buildMainListener(cfg *config.Config) *envoy_config_listener_
 
 	if cfg.Options.InsecureServer {
 		filter := buildMainHTTPConnectionManagerFilter(cfg.Options,
-			getAllRouteableDomains(cfg.Options, cfg.Options.Addr))
+			getAllRouteableDomains(cfg.Options, cfg.Options.Addr), "")
 
 		return &envoy_config_listener_v3.Listener{
 			Name:            "http-ingress",
@@ -94,7 +95,7 @@ func (srv *Server) buildMainListener(cfg *config.Config) *envoy_config_listener_
 		ListenerFilters: listenerFilters,
 		FilterChains: buildFilterChains(cfg.Options, cfg.Options.Addr,
 			func(tlsDomain string, httpDomains []string) *envoy_config_listener_v3.FilterChain {
-				filter := buildMainHTTPConnectionManagerFilter(cfg.Options, httpDomains)
+				filter := buildMainHTTPConnectionManagerFilter(cfg.Options, httpDomains, tlsDomain)
 				filterChain := &envoy_config_listener_v3.FilterChain{
 					Filters: []*envoy_config_listener_v3.Filter{filter},
 				}
@@ -128,14 +129,18 @@ func buildFilterChains(
 	var chains []*envoy_config_listener_v3.FilterChain
 	for _, domain := range tlsDomains {
 		// first we match on SNI
-		chains = append(chains, callback(domain, allDomains))
+		chains = append(chains, callback(domain, getRouteableDomainsForTLSDomain(options, addr, domain)))
 	}
 	// if there are no SNI matches we match on HTTP host
 	chains = append(chains, callback("*", allDomains))
 	return chains
 }
 
-func buildMainHTTPConnectionManagerFilter(options *config.Options, domains []string) *envoy_config_listener_v3.Filter {
+func buildMainHTTPConnectionManagerFilter(
+	options *config.Options,
+	domains []string,
+	tlsDomain string,
+) *envoy_config_listener_v3.Filter {
 	var virtualHosts []*envoy_config_route_v3.VirtualHost
 	for _, domain := range domains {
 		vh := &envoy_config_route_v3.VirtualHost{
@@ -203,18 +208,7 @@ func buildMainHTTPConnectionManagerFilter(options *config.Options, domains []str
 		InlineCode: luascripts.RemoveImpersonateHeaders,
 	})
 
-	var maxStreamDuration *durationpb.Duration
-	if options.WriteTimeout > 0 {
-		maxStreamDuration = ptypes.DurationProto(options.WriteTimeout)
-	}
-
-	tc := marshalAny(&envoy_http_connection_manager.HttpConnectionManager{
-		CodecType:  envoy_http_connection_manager.HttpConnectionManager_AUTO,
-		StatPrefix: "ingress",
-		RouteSpecifier: &envoy_http_connection_manager.HttpConnectionManager_RouteConfig{
-			RouteConfig: buildRouteConfiguration("main", virtualHosts),
-		},
-		HttpFilters: []*envoy_http_connection_manager.HttpFilter{
+	filters := []*envoy_http_connection_manager.HttpFilter{
 		{
 			Name: "envoy.filters.http.lua",
 			ConfigType: &envoy_http_connection_manager.HttpFilter_TypedConfig{
@@ -239,10 +233,34 @@ func buildMainHTTPConnectionManagerFilter(options *config.Options, domains []str
 				TypedConfig: cleanUpstreamLua,
 			},
 		},
-			{
+	}
+	if tlsDomain != "" && tlsDomain != "*" {
+		fixMisdirectedLua := marshalAny(&envoy_extensions_filters_http_lua_v3.Lua{
+			InlineCode: fmt.Sprintf(luascripts.FixMisdirected),
+		})
+		filters = append(filters, &envoy_http_connection_manager.HttpFilter{
+			Name: "envoy.filters.http.lua",
+			ConfigType: &envoy_http_connection_manager.HttpFilter_TypedConfig{
+				TypedConfig: fixMisdirectedLua,
+			},
+		})
+	}
+	filters = append(filters, &envoy_http_connection_manager.HttpFilter{
 		Name: "envoy.filters.http.router",
+	})
+
+	var maxStreamDuration *durationpb.Duration
+	if options.WriteTimeout > 0 {
+		maxStreamDuration = ptypes.DurationProto(options.WriteTimeout)
+	}
+
+	tc := marshalAny(&envoy_http_connection_manager.HttpConnectionManager{
+		CodecType:  envoy_http_connection_manager.HttpConnectionManager_AUTO,
+		StatPrefix: "ingress",
+		RouteSpecifier: &envoy_http_connection_manager.HttpConnectionManager_RouteConfig{
+			RouteConfig: buildRouteConfiguration("main", virtualHosts),
 		},
-		},
+		HttpFilters: filters,
 		AccessLog:   buildAccessLogs(options),
 		CommonHttpProtocolOptions: &envoy_config_core_v3.HttpProtocolOptions{
 			IdleTimeout:       ptypes.DurationProto(options.IdleTimeout),
@@ -421,6 +439,17 @@ func (srv *Server) buildDownstreamTLSContext(cfg *config.Config, domain string)
 	}
 }
 
+func getRouteableDomainsForTLSDomain(options *config.Options, addr string, tlsDomain string) []string {
+	allDomains := getAllRouteableDomains(options, addr)
+	var filtered []string
+	for _, domain := range allDomains {
+		if urlutil.StripPort(domain) == tlsDomain {
+			filtered = append(filtered, domain)
+		}
+	}
+	return filtered
+}
+
 func getAllRouteableDomains(options *config.Options, addr string) []string {
 	lookup := map[string]struct{}{}
 	if config.IsAuthenticate(options.Services) && addr == options.Addr {

internal/controlplane/xds_listeners_test.go

@@ -23,7 +23,7 @@ const (
 func Test_buildMainHTTPConnectionManagerFilter(t *testing.T) {
 	options := config.NewDefaultOptions()
 	options.SkipXffAppend = true
-	filter := buildMainHTTPConnectionManagerFilter(options, []string{"example.com"})
+	filter := buildMainHTTPConnectionManagerFilter(options, []string{"example.com"}, "*")
 	testutil.AssertProtoJSONEqual(t, `{
 		"name": "envoy.filters.network.http_connection_manager",
 		"typedConfig": {

internal/controlplane/xds_lua.go

@@ -16,6 +16,7 @@ var luascripts struct {
 	ExtAuthzSetCookie        string
 	CleanUpstream            string
 	RemoveImpersonateHeaders string
+	FixMisdirected           string
 }
 
 func init() {
@@ -28,6 +29,7 @@ func init() {
 		"/clean-upstream.lua":             &luascripts.CleanUpstream,
 		"/ext-authz-set-cookie.lua":       &luascripts.ExtAuthzSetCookie,
 		"/remove-impersonate-headers.lua": &luascripts.RemoveImpersonateHeaders,
+		"/fix-misdirected.lua":            &luascripts.FixMisdirected,
 	}
 
 	err = fs.Walk(hfs, "/", func(p string, fi os.FileInfo, err error) error {