The attached patch optimizes the validation of the name of an interface. Signed-off-by: Stefan Berger Index: libvirt-acl/src/conf/domain_conf.c =================================================================== --- libvirt-acl.orig/src/conf/domain_conf.c +++ libvirt-acl/src/conf/domain_conf.c @@ -1795,7 +1795,7 @@ cleanup: static bool isValidIfname(const char *ifname) { - return (strspn(ifname, VALID_IFNAME_CHARS) == strlen(ifname)); + return ifname[strspn(ifname, VALID_IFNAME_CHARS)] == 0; }