sftpserver: Add missing return check for ssh_buffer_add_data()

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

src/sftpserver.c

@@ -73,9 +73,14 @@ sftp_client_message sftp_get_client_message(sftp_session sftp) {
       return NULL;
   }
 
-  ssh_buffer_add_data(msg->complete_message,
+  rc = ssh_buffer_add_data(msg->complete_message,
                            ssh_buffer_get(payload),
                            ssh_buffer_get_len(payload));
+  if (rc < 0) {
+      ssh_set_error_oom(session);
+      sftp_client_message_free(msg);
+      return NULL;
+  }
 
   ssh_buffer_get_u32(payload, &msg->id);