add optional gRPC max message size limit to trillian logserver and logsigner (google#3801)

* add optional gRPC max message size limit to trillian logserver and logsigner

Signed-off-by: Firas Ghanmi <fghanmi@redhat.com>

* update CHANGELOG.md

Signed-off-by: Firas Ghanmi <fghanmi@redhat.com>

---------

Signed-off-by: Firas Ghanmi <fghanmi@redhat.com>

Author: fghanmi

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 * Bump golangci-lint to v2.1.6
 * Fix leader resignation during a graceful shutdown by @osmman in https://github.com/google/trillian/pull/3790
+* Add optional gRPC message size limit via `--max_msg_size_bytes` flag by @fghanmi in https://github.com/google/trillian/pull/3801
 
 ## v1.7.2
 

cmd/trillian_log_server/main.go

@@ -76,6 +76,7 @@ var (
 	// Profiling related flags.
 	cpuProfile = flag.String("cpuprofile", "", "If set, write CPU profile to this file")
 	memProfile = flag.String("memprofile", "", "If set, write memory profile to this file")
+	maxMsgSize = flag.Int("max_msg_size_bytes", 0, "Optional max gRPC message size in bytes")
 )
 
 func main() {
@@ -107,6 +108,9 @@ func main() {
 		options = append(options, opts...)
 	}
 
+	if *maxMsgSize > 0 {
+		options = append(options, grpc.MaxRecvMsgSize(*maxMsgSize))
+	}
 	sp, err := storage.NewProvider(*storageSystem, mf)
 	if err != nil {
 		klog.Exitf("Failed to get storage provider: %v", err)

cmd/trillian_log_signer/main.go

@@ -84,6 +84,7 @@ var (
 	// Profiling related flags.
 	cpuProfile = flag.String("cpuprofile", "", "If set, write CPU profile to this file")
 	memProfile = flag.String("memprofile", "", "If set, write memory profile to this file")
+	maxMsgSize = flag.Int("max_msg_size_bytes", 0, "Optional max gRPC message size in bytes")
 )
 
 func main() {
@@ -194,12 +195,17 @@ func main() {
 		defer pprof.StopCPUProfile()
 	}
 
+	var options []grpc.ServerOption
+	if *maxMsgSize > 0 {
+		options = append(options, grpc.MaxRecvMsgSize(*maxMsgSize))
+	}
 	m := serverutil.Main{
 		RPCEndpoint:      *rpcEndpoint,
 		HTTPEndpoint:     *httpEndpoint,
 		TLSCertFile:      *tlsCertFile,
 		TLSKeyFile:       *tlsKeyFile,
 		StatsPrefix:      "logsigner",
+		ExtraOptions:     options,
 		DBClose:          sp.Close,
 		Registry:         registry,
 		RegisterServerFn: func(s *grpc.Server, _ extension.Registry) error { return nil },