Qual é a maneira correta de modificar o /etc/pam.d/common-auth?

Question

Por padrão, /etc/pam.d/common-auth parece com isso

$ cat /etc/pam.d/common-auth 
#
# /etc/pam.d/common-auth - authentication settings common to all services
#
# This file is included from other service-specific PAM config files,
# and should contain a list of the authentication modules that define
# the central authentication scheme for use on the system
# (e.g., /etc/shadow, LDAP, Kerberos, etc.).  The default is to use the
# traditional Unix authentication mechanisms.
#
# As of pam 1.0.1-6, this file is managed by pam-auth-update by default.
# To take advantage of this, it is recommended that you configure any
# local modules either before or after the default block, and use
# pam-auth-update to manage selection of other modules.  See
# pam-auth-update(8) for details.

# here are the per-package modules (the "Primary" block)
auth    [success=1 default=ignore]  pam_unix.so nullok_secure
# here's the fallback if no module succeeds
auth    requisite           pam_deny.so
# prime the stack with a positive return value if there isn't one already;
# this avoids us returning an error just because nothing sets a success code
# since the modules above will each just jump around
auth    required            pam_permit.so
# and here are more per-package modules (the "Additional" block)
auth    optional            pam_cap.so 
# end of pam-auth-update config

Eu tenho modificado com sucesso o arquivo acima auth required pam_exec.so expose_authtok /path/to/some/script

Estou revisando se o acima é a maneira recomendada de modificar o PAM ou se eu deveria estar criando uma configuração PAM em /usr/share/pam-configs/my-custom-thing .

A criação de um PAM-config é a maneira correta de fazer a alteração necessária no PAM?