.\" Copyright (c) 2019-2020 Rodolphe Bréard <rodolphe@breard.tf>
.\"
.\" Copying and distribution of this file, with or without modification,
.\" are permitted in any medium without royalty provided the copyright
.\" notice and this notice are preserved.  This file is offered as-is,
.\" without any warranty.
.Dd June 12, 2020
.Dt ACMED.TOML 5
.Os
.Sh NAME
.Nm acmed.toml
.Nd ACMEd configuration file
.Sh DESCRIPTION
.Nm
is the configuration file for
.Xr acmed 8 .
It is written in the
.Em TOML
format. The allowed elements are described below.
.Bl -tag
.It Ic include
Array containing the path to configuration file to include. The path can be either relative or absolute. If relative, it is relative to the configuration file which included it.
.Pp
In case or overlapping global option definition, the one of the last included file will be used. For example, if a file
.Em A
includes files
.Em B
and
.Em C
and all three defines the same global option, the final value will be the one defined in file
.Em C .
.It Ic global
Table containing the global configuration options.
.Bl -tag
.It Cm accounts_directory Ar string
Specify the directory where the accounts private and public keys are stored.
.It Cm certificates_directory Ar string
Specify the directory where the certificates and their associated private keys are stored.
.It Cm cert_file_mode Ar integer
Specify the permissions to use for newly-created certificates files. See
.Xr chmod 2
for more details.
.It Cm cert_file_user Ar username|user_id Ft string
Specify the user who will own newly-created certificates files. See
.Xr chown 2
for more details.
.It Cm cert_file_group Ar group_name|group_id Ft string
Specify the group who will own newly-created certificates files. See
.Xr chown 2
for more details.
.It Ic env Ar table
Table of environment variables that will be accessible from hooks.
.It Cm pk_file_mode Ar integer
Specify the permissions to use for newly-created private-key files. See
.Xr chmod 2
for more details.
.It Cm pk_file_user Ar username|user_id Ft string
Specify the user who will own newly-created private-key files. See
.Xr chown 2
for more details.
.It Cm pk_file_group Ar group_name|group_id Ft string
Specify the group who will own newly-created private-key files. See
.Xr chown 2
for more details.
.El
.It Ic rate-limit
Array of table where each element defines a HTTPS rate limit.
.Bl -tag
.It Cm name Ar string
The name the rate limit is registered under. Must be unique.
.It Cm number Ar integer
Number of requests authorized withing the time period.
.It Cm period Ar string
Period of time during which a maximal number of requests is authorized. The format is described in the
.Sx TIME PERIODS
section.
.El
.It Ic endpoint
Array of table where each element defines a Certificate Authority
.Pq CA
which may be used to request certificates.
.Bl -tag
.It Cm name Ar string
The name the endpoint is registered under. Must be unique.
.It Cm rate_limits Ar array
Array containing the names of the HTTPS rate limits to apply.
.It Cm tos_agreed Ar boolean
Set whether or not the user agrees to the Terms Of Service
.Pq TOS .
.It Cm url Ar string
The endpoint's directory URL.
.El
.It Ic hook
Array of table where each element defines a command that will be launched at a defined point. See section
.Sx WRITING A HOOK
for more details.
.Bl -tag
.It Cm allow_failure Ar boolean
Defines if an error return value for this hook is allowed or not. If not allowed, a failure in this hook will fail the whole certificate request process. Default is false.
.It Cm name Ar string
The name the hook is registered under. Must be unique.
.It Cm type Ar array
Array of strings. Possible types are:
.Bl -dash -compact
.It
challenge-http-01
.It
challenge-http-01-clean
.It
challenge-dns-01
.It
challenge-dns-01-clean
.It
challenge-tls-alpn-01
.It
challenge-tls-alpn-01-clean
.It
file-pre-create
.It
file-pre-edit
.It
file-post-create
.It
file-post-edit
.It
post-operation
.El
.It Ic cmd Ar string
The name of the command that will be launched.
.It Ic args Ar array
Array of strings representing the command's arguments.
.It Ic stdin Ar string
Path to the file that will be written into the command's standard intput. Mutually exclusive with
.Em stdin_str .
.It Ic stdin_str Ar string
String that will be written into the command's standard input. Mutually exclusive with
.Em stdin .
.It Ic stdout Ar string
Path to the file where the command's standard output if written.
.It Ic stderr Ar string
Path to the file where the command's standard error output if written.
.El
.It Ic group
Array of table allowing to group several hooks as one. A group is considered as new hook.
.Bl -tag
.It Cm name Ar string
The name the group is registered under. This name is considered as a hook name. Must be unique.
.It Cm hooks Ar array
Array containing the names of the hooks that are grouped. The hooks are guaranteed to be called sequentially in the declaration order.
.El
.It Ic account
Array of table representing an account on one or several CA.
.Bl -tag
.It Ic name Ar string
The name the account is registered under. Must be unique.
.It Ic email Ar string
The email address used to contact the account's holder.
.El
.It Ic certificate
Array of table representing a certificate that will be requested to a CA.
.Pp
Note that certificates are identified by the first domain in the list of domains. That means that if you reorder the domains so that a different domain is at the first position, a new certificate with a new name will be issued.
.Bl -tag
.It Ic account Ar string
Name of the account to use.
.It Ic endpoint Ar string
Name of the endpoint to use.
.It Ic env Ar table
Table of environment variables that will be accessible from hooks.
.It Ic domains Ar array
Array of tables listing the domains that should be included in the certificate along with the challenge to use for each one.
.Bl -tag
.It Ic challenge Ar string
The name of the challenge to use to prove the domain's ownership. Possible values are:
.Bl -dash -compact
.It
http-01
.It
dns-01
.It
tls-alpn-01
.El
.It Ic dns Ar string
The domain name.
.It Ic env Ar table
Table of environment variables that will be accessible from hooks.
.El
.It Ic algorithm Ar string
Name of the asymetric cryptography algorithm used to generate the certificate's key pair. Possible values are :
.Bl -dash -compact
.It
rsa2048
.Aq default
.It
rsa4096
.It
ecdsa_p256
.It
ecdsa_p384
.El
.It Ic kp_reuse Ar boolean
Set whether or not the private key should be reused when renewing the certificate. Default is false.
.It Ic directory Ar string
Path to the directory where certificates and their associated private keys are stored.
.It Ic hooks Ar array
Names of hooks that will be called when requesting a new certificate. The hooks are guaranteed to be called sequentially in the declaration order.
.El
.Sh WRITING A HOOK
When requesting a certificate from a CA using ACME, there are three steps that are hard to automatize. The first one is solving challenges in order to prove the ownership of every domains to be included: It requires to interact with the configuration of other services, hence depends on how the infrastructure works. The second one is restarting all the services that use a given certificate, for the same reason. The last one is archiving: Although several default methods can be implemented, sometimes admins wants or are required to do it in a different way.
.Pp
In order to allow full automation of the three above steps without imposing arbitrary restrictions or methods,
.Xr acmed 8
uses hooks. Fundamentally, a hook is a command line template that will be called at a specific time of the process. Such an approach allows admins to use any executable script or program located on the machine to customize the process.
.Pp
For a given certificate, hooks are guaranteed to be called sequentially in the declaration order. It is therefore possible to have a hook that depends on another one. Nevertheless, several certificates may be renewed at the same time. Hence, hooks shall not use globing or any other action that may disrupt hooks called by a different certificate.
.Pp
A hook has a type that will influence both the moment it is called and the available template variables. It is possible to declare several types. In such a case, the hook will be invoked whenever one of its type request it. When called, the hook only have access to template variable for the current type. If a hook uses a template variable that does not exists for the current type it is invoked for, the variable is empty.
.Pp
When writing a hook, the values of
.Em args ,
.Em stdin ,
.Em stdin_str ,
.Em stdout
and
.Em stderr
are considered as template strings whereas
.Em cmd
is not. The template syntax is
.Em Handlebars .
See the
.Sx STANDARDS
section for a link to the
.Em Handlebars
specifications.
.Pp
The available types and the associated template variable are described below.
.Bl -tag
.It Ic challenge-http-01
Invoked when the ownership of a domain must be proved using the
.Em http-01
challenge. The available template variables are:
.Bl -tag -compact
.It Cm challenge Ar string
The name of the challenge type
.Aq http-01 .
Mostly used in hooks with multiple types.
.It Cm domain Ar string
The domain name whom ownership is currently being validated.
.It Cm env Ar array
Array containing all the environment variables.
.It Cm file_name Ar string
Name of the file containing the proof. This is not a full path and does not include the
.Ql .well-known/acme-challenge/
prefix.
.It Cm is_clean_hook Ar bool
False
.It Cm proof Ar string
The content of the proof that must be written to
.Em file_name .
.El
.It Ic challenge-http-01-clean
Invoked once a domain ownership has been proven using the
.Em http-01
challenge. This hook is intended to remove the proof since it is no longer required. The template variables are strictly identical to those given in the corresponding
.Em challenge-http-01
hook, excepted
.Em is_clean_hook
which is set to
.Em true .
.It Ic challenge-dns-01
Invoked when the ownership of a domain must be proved using the
.Em dns-01
challenge. The available template variables are:
.Bl -tag -compact
.It Cm challenge Ar string
The name of the challenge type
.Aq dns-01 .
Mostly used in hooks with multiple types.
.It Cm domain Ar string
The domain name whom ownership is currently being validated.
.It Cm env Ar array
Array containing all the environment variables.
.It Cm is_clean_hook Ar bool
False
.It Cm proof Ar string
The content of the proof that must be written to a
.Ql TXT
entry of the DNS zone for the
.Ql _acme-challenge
subdomain.
.El
.It Ic challenge-dns-01-clean
Invoked once a domain ownership has been proven using the
.Em dns-01
challenge. This hook is intended to remove the proof since it is no longer required. The template variables are strictly identical to those given in the corresponding
.Em challenge-dns-01
hook, excepted
.Em is_clean_hook
which is set to
.Em true .
.It Ic challenge-tls-alpn-01
Invoked when the ownership of a domain must be proved using the
.Em tls-alpn-01
challenge. The available template variables are:
.Bl -tag -compact
.It Cm challenge Ar string
The name of the challenge type
.Aq tls-alpn-01 .
Mostly used in hooks with multiple types.
.It Cm domain Ar string
The domain name whom ownership is currently being validated.
.It Cm env Ar array
Array containing all the environment variables.
.It Cm is_clean_hook Ar bool
False
.It Cm proof Ar string
Plain-text representation of the
.Em acmeIdentifier
extension that should be used in the self-signed certificate presented when a TLS connection is initiated with the
.Qd acme-tls/1
ALPN extension value.
.Xr acmed 8
will not generate the certificate itself since it can be done using
.Xr tacd 8 .
.El
.It Ic challenge-tls-alpn-01-clean
Invoked once a domain ownership has been proven using the
.Em tls-alpn-01
challenge. This hook is intended to remove the proof since it is no longer required. The template variables are strictly identical to those given in the corresponding
.Em challenge-tls-alpn-01
hook, excepted
.Em is_clean_hook
which is set to
.Em true .
.It Ic file-pre-create
Invoked
.Em before
a non-existent file
.Em created .
The available template variables are:
.Bl -tag -compact
.It Cm env Ar array
Array containing all the environment variables.
.It Cm file_directory Ar string
Name of the directory where the impacted file is located.
.It Cm file_name Ar string
Name of the impacted file.
.It Cm file_path Ar string
Full path to the impacted file.
.El
.It Ic file-pre-edit
Invoked
.Em before
an existent file
.Em modified .
The available template variables are the same as those available for the
.Em file-pre-create
type.
.It Ic file-post-create
Invoked
.Em after
a non-existent file
.Em created .
The available template variables are the same as those available for the
.Em file-pre-create
type.
.It Ic file-post-edit
Invoked
.Em after
an existent file
.Em modified .
The available template variables are the same as those available for the
.Em file-pre-create
type.
.It Ic post-operation
Invoked at the end of the certificate request process. The available template variables are:
.Bl -tag -compact
.It Cm algorithm Ar string
Name of the algorithm used in the certificate.
.It Cm domains Ar string
Array containing the domain names included in the requested certificate.
.It Cm env Ar array
Array containing all the environment variables.
.It Cm is_success Ar boolean
True if the certificate request is successful.
.It Cm status Ar string
Human-readable status. If the certificate request failed, it contains the error description.
.El
.El
.Sh DEFAULT HOOKS
Because many people have the same needs, ACMEd comes with a set of hooks that should serve most situations. Hook names being unique, the following names and any other name starting by those is reserved and should not be used.
.Bl -tag
.It Pa git
This hook uses
.Xr git 1
to archive private keys, public keys and certificates. It is possible to customize the commit username and email by using respectively the
.Ev GIT_USERNAME
and
.Ev GIT_EMAIL
environment variables.
.It Pa http-01-echo
This hook is designed to solve the http-01 challenge. For this purpose, it will write the proof into
.Pa {{env.HTTP_ROOT}}/{{domain}}/.well-known/acme-challenge/{{file_name}} .
.Pp
The web server must be configured so the file
.Pa http://{{domain}}/.well-known/acme-challenge/{{file_name}}
can be accessed from the CA.
.Pp
If
.Ev HTTP_ROOT
is not specified, it will be set to
.Pa /var/www .
.It Pa tls-alpn-01-tacd-tcp
This hook is designed to solve the tls-alpn-01 challenge using
.Xr tacd 8 .
It requires
.Xr pkill 1
to support the
.Em Ar -F
option.
.Pp
.Xr tacd 8
will listen on the host defined by the
.Ev TACD_HOST
environment variable (default is the domain to be validated) and on the port defined by the
.Ev TACD_PORT
environment variable (default is 5001).
.Pp
.Xr tacd 8
will store its pid into
.Pa {{TACD_PID_ROOT}}/tacd_{{domain}}.pid .
If
.Ev TACD_PID_ROOT
is not specified, it will be set to
.Pa /run .
.It Pa tls-alpn-01-tacd-unix
This hook is designed to solve the tls-alpn-01 challenge using
.Xr tacd 8 .
It requires
.Xr pkill 1
to support the
.Em Ar -F
option.
.Pp
.Xr tacd 8
will listen on the unix socket
.Pa {{env.TACD_SOCK_ROOT}}/tacd_{{domain}}.sock .
If
.Ev TACD_SOCK_ROOT
is not specified, it will be set to
.Pa /run .
.Pp
.Xr tacd 8
will store its pid into
.Pa {{TACD_PID_ROOT}}/tacd_{{domain}}.pid .
If
.Ev TACD_PID_ROOT
is not specified, it will be set to
.Pa /run .
.El
.Sh TIME PERIODS
ACMEd uses its own time period format, which is vaguely inspired by the ISO 8601 one. Periods are formatted as
.Ar PM[PM...]
where
.Ar M
is case sensitive character representing a length and
.Ar P
is an integer representing a multiplayer for the following length. The authorized length are:
.Bl -dash -compact
.It
.Ar s :
second
.It
.Ar m :
minute
.It
.Ar h :
hour
.It
.Ar d :
day
.It
.Ar w :
week
.El
The
.Ar PM
couples can be specified multiple times and in any order.
.Pp
For example,
.Dq 1d42s and
.Dq 40s20h4h2s
both represents a period of one day and forty-two seconds.
.Sh FILES
.Bl -tag
.It Pa /etc/acmed/acmed.toml
Default
.Xr acmed 8
configuration file.
.It Pa /etc/acmed/accounts
Default accounts private and public keys directory.
.It Pa /etc/acmed/certs
Default certificates and associated private keys directory.
.Sh EXAMPLES
The following example defines a typical endpoint, account and certificate for a domain and several subdomains.
.Bd -literal -offset indent
[[endpoint]]
name = "example name"
url = "https://acme.example.org/directory"
tos_agreed = true

[[account]]
name = "my test account"
email = "certs@exemple.net"

[[certificate]]
endpoint = "example name"
account = "my test account"
domains = [
    { dns = "exemple.net", challenge = "http-01"},
    { dns = "1.exemple.net", challenge = "dns-01"},
    { dns = "2.exemple.net", challenge = "tls-alpn-01", env.TACD_PORT="5010"},
    { dns = "3.exemple.net", challenge = "tls-alpn-01", env.TACD_PORT="5011"},
]
hooks = ["git", "http-01-echo", "tls-alpn-01-tacd-tcp", "some-dns-01-hook"]
env.HTTP_ROOT = "/srv/http"
.Ed
.Pp
It is possible to use
.Xr echo 1
to solve the
.Em http-01
challenge and
.Xr rm 1
to clean it.
.Xr mkdir 1
and
.Xr chmod 1
are used to prevent issues related to file access.
.Bd -literal -offset indent
[[hook]]
name = "http-01-echo-mkdir"
type = ["challenge-http-01"]
cmd = "mkdir"
args = [
    "-m", "0755",
    "-p", "{{%if env.HTTP_ROOT}}{{env.HTTP_ROOT}}{{else}}/var/www{{/if}}/{{domain}}/.well-known/acme-challenge"
]

[[hook]]
name = "http-01-echo-echo"
type = ["challenge-http-01"]
cmd = "echo"
args = ["{{proof}}"]
stdout = "{{%if env.HTTP_ROOT}}{{env.HTTP_ROOT}}{{else}}/var/www{{/if}}/{{domain}}/.well-known/acme-challenge/{{file_name}}"

[[hook]]
name = "http-01-echo-chmod"
type = ["challenge-http-01-clean"]
cmd = "chmod"
args = [
    "a+r",
    "{{%if env.HTTP_ROOT}}{{env.HTTP_ROOT}}{{else}}/var/www{{/if}}/{{domain}}/.well-known/acme-challenge/{{file_name}}"
]

[[hook]]
name = "http-01-echo-clean"
type = ["challenge-http-01-clean"]
cmd = "rm"
args = [
    "-f",
    "{{%if env.HTTP_ROOT}}{{env.HTTP_ROOT}}{{else}}/var/www{{/if}}/{{domain}}/.well-known/acme-challenge/{{file_name}}"
]
.Ed
.Pp
The hooks from the previous example can be grouped in order to reduce the number of hooks to define in the certificate.
.Bd -literal -offset indent
[[group]]
name = "http-01-echo-var-www"
hooks = [
    "http-01-echo-mkdir",
    "http-01-echo-echo",
    "http-01-echo-chmod",
    "http-01-echo-clean"
]

[[certificate]]
# Some fields omitted
hooks = ["http-01-echo"]
env.HTTP_ROOT = "/srv/http"
.Ed
.Pp

It is also possible to use
.Xr sendmail 8
in a hook in order to notif someone when the certificate request process is done.
.Bd -literal -offset indent
[[hook]]
name = "email-report"
type = ["post-operation"]
cmd = "sendmail"
args = [
    "-f", "noreply.certs@example.net",
    "contact@example.net"
]
stdin_str = """Subject: Certificate renewal {{#if is_success}}succeeded{{else}}failed{{/if}} for {{domains.[0]}}

The following certificate has {{#unless is_success}}*not* {{/unless}}been renewed.
domains: {{#each domains}}{{#if @index}}, {{/if}}{{this}}{{/each}}
algorithm: {{algorithm}}
status: {{status}}"""
.Ed
.Sh SEE ALSO
.Xr acmed 8 ,
.Xr tacd 8
.Sh STANDARDS
.Bl
.It
.Rs
.%A Tom Preston-Werner
.%D July 2018
.%T TOML v0.5.0
.%U https://github.com/toml-lang/toml
.Re
.It
.Rs
.%A Yehuda Katz
.%T Handlebars
.%U https://handlebarsjs.com/
.Re
.El
.Sh AUTHORS
.An Rodolphe Bréard
.Aq rodolphe@breard.tf