Libvirt: libvirt: newline injection in network xml dns txt/srv fields allows dnsmasq config directive injection

An injection vulnerability was found in libvirt's virtual network driver. The network XML parser does not strip newline characters from DNS TXT record value attributes and SRV record domain/target attributes. These values are written verbatim into the dnsmasq configuration file generated by the network driver, allowing a user with permission to define virtual networks to inject arbitrary dnsmasq configuration directives such as dhcp-script, leading to arbitrary command execution as root.