libvirt/daemon/libvirtd.sasl

# If you want to use the non-TLS socket, then you *must* pick a
# mechanism which provides session encryption as well as
# authentication.
#
# If you are only using TLS, then you can turn on any mechanisms
# you like for authentication, because TLS provides the encryption
#
# If you are only using UNIX, sockets then encryption is not
# required at all.
#
# Since SASL is the default for the libvirtd non-TLS socket, we
# pick a strong mechanism by default.
#
# NB, previously DIGEST-MD5 was set as the default mechanism for
# libvirt. Per RFC 6331 this is vulnerable to many serious security
# flaws and should no longer be used. Thus GSSAPI is now the default.
#
# To use GSSAPI requires that a libvirtd service principal is
# added to the Kerberos server for each host running libvirtd.
# This principal needs to be exported to the keytab file listed below
mech_list: gssapi

# If using a TLS socket or UNIX socket only, it is possible to
# enable plugins which don't provide session encryption. The
# 'scram-sha-1' plugin allows plain username/password authentication
# to be performed
#
#mech_list: scram-sha-1

#
# You can also list many mechanisms at once, then the user can choose
# by adding  '?auth=sasl.gssapi' to their libvirt URI, eg
#   qemu+tcp://hostname/system?auth=sasl.gssapi
#mech_list: scram-sha-1 gssapi

# Some older builds of MIT kerberos on Linux ignore this option &
# instead need KRB5_KTNAME env var.
# For modern Linux, and other OS, this should be sufficient
#
keytab: /etc/libvirt/krb5.tab

# If using scram-sha-1 for username/passwds, then this is the file
# containing the passwds. Use 'saslpasswd2 -a libvirt [username]'
# to add entries, and 'sasldblistusers2 -f [sasldb_path]' to browse it
#sasldb_path: /etc/libvirt/passwd.db