Adding a method in channel creds to remove any attached call creds.

This will be useful when talking to non-trusted load balancer (balancers
which are not able to impersonate real backends) as these balancers
should not receive bearer tokens.

6 files changed, 36 insertions, 5 deletions

diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.c
index 850e41e646..d55d00b7b6 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.c
@@ -242,8 +242,17 @@ static grpc_security_status composite_channel_create_security_connector(
   return status;
 }
 
+static grpc_channel_credentials *
+composite_channel_duplicate_without_call_credentials(
+    grpc_channel_credentials *creds) {
+  grpc_composite_channel_credentials *c =
+      (grpc_composite_channel_credentials *)creds;
+  return grpc_channel_credentials_ref(c->inner_creds);
+}
+
 static grpc_channel_credentials_vtable composite_channel_credentials_vtable = {
-    composite_channel_destruct, composite_channel_create_security_connector};
+    composite_channel_destruct, composite_channel_create_security_connector,
+    composite_channel_duplicate_without_call_credentials};
 
 grpc_channel_credentials *grpc_composite_channel_credentials_create(
     grpc_channel_credentials *channel_creds, grpc_call_credentials *call_creds,
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.h b/src/core/lib/security/credentials/composite/composite_credentials.h
index 0d8966f464..f8425c2b76 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.h
+++ b/src/core/lib/security/credentials/composite/composite_credentials.h
@@ -53,7 +53,7 @@ grpc_call_credentials *grpc_credentials_contains_type(
     grpc_call_credentials *creds, const char *type,
     grpc_call_credentials **composite_creds);
 
-/* -- Channel composite credentials. -- */
+/* -- Composite channel credentials. -- */
 
 typedef struct {
   grpc_channel_credentials base;
@@ -61,7 +61,7 @@ typedef struct {
   grpc_call_credentials *call_creds;
 } grpc_composite_channel_credentials;
 
-/* -- Composite credentials. -- */
+/* -- Composite call credentials. -- */
 
 typedef struct {
   grpc_call_credentials base;
diff --git a/src/core/lib/security/credentials/credentials.c b/src/core/lib/security/credentials/credentials.c
index 029a357261..1149e5c2ed 100644
--- a/src/core/lib/security/credentials/credentials.c
+++ b/src/core/lib/security/credentials/credentials.c
@@ -138,6 +138,18 @@ grpc_security_status grpc_channel_credentials_create_security_connector(
       channel_creds, NULL, target, args, sc, new_args);
 }
 
+grpc_channel_credentials *
+grpc_channel_credentials_duplicate_without_call_credentials(
+    grpc_channel_credentials *channel_creds) {
+  if (channel_creds != NULL && channel_creds->vtable != NULL &&
+      channel_creds->vtable->duplicate_without_call_credentials != NULL) {
+    return channel_creds->vtable->duplicate_without_call_credentials(
+        channel_creds);
+  } else {
+    return grpc_channel_credentials_ref(channel_creds);
+  }
+}
+
 grpc_server_credentials *grpc_server_credentials_ref(
     grpc_server_credentials *creds) {
   if (creds == NULL) return NULL;
diff --git a/src/core/lib/security/credentials/credentials.h b/src/core/lib/security/credentials/credentials.h
index 8e9d842ead..6fb5b5b15a 100644
--- a/src/core/lib/security/credentials/credentials.h
+++ b/src/core/lib/security/credentials/credentials.h
@@ -107,6 +107,9 @@ typedef struct {
       grpc_channel_credentials *c, grpc_call_credentials *call_creds,
       const char *target, const grpc_channel_args *args,
       grpc_channel_security_connector **sc, grpc_channel_args **new_args);
+
+  grpc_channel_credentials *(*duplicate_without_call_credentials)(
+      grpc_channel_credentials *c);
 } grpc_channel_credentials_vtable;
 
 struct grpc_channel_credentials {
@@ -128,6 +131,13 @@ grpc_security_status grpc_channel_credentials_create_security_connector(
     const grpc_channel_args *args, grpc_channel_security_connector **sc,
     grpc_channel_args **new_args);
 
+/* Creates a version of the channel credentials without any attached call
+   credentials. This can be used in order to open a channel to a non-trusted
+   gRPC load balancer. */
+grpc_channel_credentials *
+grpc_channel_credentials_duplicate_without_call_credentials(
+    grpc_channel_credentials *creds);
+
 /* --- grpc_credentials_md. --- */
 
 typedef struct {
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.c
index 51cafd986f..ea4cb76fb9 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.c
@@ -61,7 +61,7 @@ fake_transport_security_server_create_security_connector(
 
 static grpc_channel_credentials_vtable
     fake_transport_security_credentials_vtable = {
-        NULL, fake_transport_security_create_security_connector};
+        NULL, fake_transport_security_create_security_connector, NULL};
 
 static grpc_server_credentials_vtable
     fake_transport_security_server_credentials_vtable = {
diff --git a/src/core/lib/security/credentials/ssl/ssl_credentials.c b/src/core/lib/security/credentials/ssl/ssl_credentials.c
index 545bca9d98..0dc1fccec4 100644
--- a/src/core/lib/security/credentials/ssl/ssl_credentials.c
+++ b/src/core/lib/security/credentials/ssl/ssl_credentials.c
@@ -95,7 +95,7 @@ static grpc_security_status ssl_create_security_connector(
 }
 
 static grpc_channel_credentials_vtable ssl_vtable = {
-    ssl_destruct, ssl_create_security_connector};
+    ssl_destruct, ssl_create_security_connector, NULL};
 
 static void ssl_build_config(const char *pem_root_certs,
                              grpc_ssl_pem_key_cert_pair *pem_key_cert_pair,