Index: squidclamav-6.1/src/squidclamav.c
===================================================================
--- squidclamav-6.1.orig/src/squidclamav.c
+++ squidclamav-6.1/src/squidclamav.c
@@ -427,8 +427,12 @@ int squidclamav_check_preview_handler(ch
      } else {
 	data->user = NULL;
      }
-     data->clientip = ci_buffer_alloc(strlen(clientip)+1);
-     strcpy(data->clientip, clientip);
+     if (clientip != NULL) {
+       data->clientip = ci_buffer_alloc(strlen(clientip)+1);
+       strcpy(data->clientip, clientip);
+     } else {
+       data->clientip = NULL;
+     }
 
      data->body = ci_simple_file_new(MAX_OBJECT_SIZE);
      if (SEND_PERCENT_BYTES >= 0 && START_SEND_AFTER == 0) {