--- a/src/lxc/tools/lxc_attach.c
+++ b/src/lxc/tools/lxc_attach.c
@@ -153,6 +153,8 @@
 	.checker      = NULL,
 	.log_priority = "ERROR",
 	.log_file     = "none",
+	.uid          = LXC_INVALID_UID,
+	.gid          = LXC_INVALID_GID,
 };
 
 static int my_parser(struct lxc_arguments *args, int c, char *arg)
@@ -366,10 +368,10 @@
 			goto out;
 	}
 
-	if (my_args.uid)
+	if (my_args.uid != LXC_INVALID_UID)
 		attach_options.uid = my_args.uid;
 
-	if (my_args.gid)
+	if (my_args.gid != LXC_INVALID_GID)
 		attach_options.gid = my_args.gid;
 
 	if (command.program) {
--- a/src/lxc/tools/lxc_execute.c
+++ b/src/lxc/tools/lxc_execute.c
@@ -84,6 +84,8 @@
 	.log_priority = "ERROR",
 	.log_file     = "none",
 	.daemonize    = 0,
+	.uid          = LXC_INVALID_UID,
+	.gid          = LXC_INVALID_GID,
 };
 
 static int my_parser(struct lxc_arguments *args, int c, char *arg)
@@ -211,7 +213,7 @@
 	if (!bret)
 		goto out;
 
-	if (my_args.uid) {
+	if (my_args.uid != LXC_INVALID_UID) {
 		char buf[256];
 
 		ret = snprintf(buf, 256, "%d", my_args.uid);
@@ -223,7 +225,7 @@
 			goto out;
 	}
 
-	if (my_args.gid) {
+	if (my_args.gid != LXC_INVALID_GID) {
 		char buf[256];
 
 		ret = snprintf(buf, 256, "%d", my_args.gid);