solution: support client TLS

docs/tls.adoc

@@ -0,0 +1,53 @@
+== Setting Up TLS/SSL Security
+
+=== Server Authentication
+
+.Example generating of server certificate
+----
+SERVER_CA="ca.myhost.dev"
+SERVER_IP="127.0.0.1"
+ORG="My Company"
+ORG_UNIT="Blockchain"
+
+certstrap init --common-name "$SERVER_CA" --passphrase "" -o "$ORG" -ou "$ORG_UNIT CA"
+certstrap request-cert -ip $SERVER_IP --passphrase ""  -o "$ORG" -ou "$ORG_UNIT Server"
+certstrap sign $SERVER_IP --CA $SERVER_CA
+
+openssl pkcs8 -topk8 -inform PEM -outform PEM -in out/$SERVER_IP.key -out out/$SERVER_IP.p8.key -nocrypt
+----
+
+.Setup application.properties
+----
+ssl=true
+ssl.cert=out/127.0.0.1.crt
+ssl.key=out/127.0.0.1.p8.key
+----
+
+.Verify server certificate
+----
+openssl s_client -alpn h2 -connect 127.0.0.1:8090 -CAfile out/ca.myhost.dev.crt
+----
+
+=== Client Authentication (optional)
+
+.Example generating of client certifiacte
+----
+CLIENT_CA="client-ca.myhost.dev"
+CLIENT_ID="client_1"
+ORG="My Company"
+ORG_UNIT="Client"
+
+certstrap init --common-name "$CLIENT_CA" --passphrase "" -o "$ORG" -ou "$ORG_UNIT CA"
+certstrap request-cert --common-name "$CLIENT_ID" --passphrase ""
+certstrap sign "$CLIENT_ID" --CA $CLIENT_CA
+----
+
+.Setup application.properties
+----
+ssl.client.cert=out/client-ca.myhost.dev.crt
+----
+
+.Vetify connection with client certificate
+----
+openssl s_client -alpn h2 -connect 127.0.0.1:8090 -CAfile out/ca.myhost.dev.crt -cert out/client_1.crt -key out/client_1.key
+----

src/main/kotlin/io/emeraldpay/dshackle/GrpcServer.kt

@@ -1,7 +1,9 @@
 package io.emeraldpay.dshackle
 
 import io.grpc.Server
-import io.grpc.ServerBuilder
+import io.grpc.netty.GrpcSslContexts
+import io.grpc.netty.NettyServerBuilder
+import io.netty.handler.ssl.ClientAuth
 import org.apache.commons.lang3.StringUtils
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
@@ -28,7 +30,7 @@ open class GrpcServer(
         log.info("Starting GRPC Server...")
         val port = env.getProperty("port", "8090").toInt()
         log.info("Listening on 0.0.0.0:$port")
-        val serverBuilder = ServerBuilder.forPort(port)
+        val serverBuilder = NettyServerBuilder.forPort(port)
         rpcs.forEach {
             serverBuilder.addService(it)
         }
@@ -47,11 +49,19 @@ open class GrpcServer(
         }
         if (secure) {
             log.info("Using TLS")
-            serverBuilder
-                    .useTransportSecurity(
-                            File(env.getProperty("ssl.cert")!!),
-                            File(env.getProperty("ssl.key")!!)
-                    )
+            val sslContextBuilder = GrpcSslContexts.forServer(
+                    File(env.getProperty("ssl.cert")!!),
+                    File(env.getProperty("ssl.key")!!)
+            )
+            if (StringUtils.isNotEmpty(env.getProperty("ssl.client.cert"))) {
+                log.info("Using TLS for client authentication")
+                sslContextBuilder.trustManager(
+                        File(env.getProperty("ssl.client.cert")!!)
+                ).clientAuth(ClientAuth.REQUIRE)
+            } else {
+                log.warn("Trust all clients")
+            }
+            serverBuilder.sslContext(sslContextBuilder.build())
         } else {
             log.warn("Using insecure transport")
         }