ACMED.TOML(5) File Formats Manual ACMED.TOML(5)
NAME
acmed.toml — ACMEd configuration file
DESCRIPTION
acmed.toml is the configuration file for acmed(8). It is written in the TOML format. The allowed elements are described below.
account
Array of table representing an account on one or several endpoint.
contacts array
Array of tables describing describing the account holder’s contact information. Each table must have one and only one key-value pair. Possible keys and their associated values are:
mailto string
A mailto URI as defined by RFC 6068. This URI cannot contains neither “hfields” nor more than one “addr-spec” in the “to” component.
env table
Table of environment variables that will be accessible from hooks.
external_account table
Table containing the information required to bind the account to an external one. Possible fields and values are:
identifier string
ASCII string identifying the key.
key string
Private key encoded in base64url without padding.
signature_algorithm string
Name of the signature algorithm used to sign the external account binding message sent to the endpoint as defined in RFC 7518. Possible values are:
−
HS256 ⟨default⟩
−
HS384
−
HS512
hooks array
Names of hooks that will be called during operations on the account storage file. The hooks are guaranteed to be called sequentially in the declaration order.
key_type string
Name of the asymmetric cryptography algorithm used to generate the key pair. Possible values are:
−
ed25519
−
ed448
−
ecdsa_p256 ⟨default⟩
−
ecdsa_p384
−
ecdsa_p521
−
rsa2048
−
rsa4096
name string
The name the account is registered under. Must be unique.
signature_algorithm string
Name of the signature algorithm used to sign the messages sent to the endpoint as defined in RFC 7518. The default value is derived from the key type. Possible values are:
−
ES256
−
ES384
−
ES512
−
RS256
certificate
Array of table representing a certificate that will be requested to a CA.
Note that, by default, certificates are identified by the first identifier in the list of identifiers. That means that if you reorder the identifiers so that a different identifier is at the first position, a new certificate with a new name will be issued.
account string
Name of the account to use.
csr_digest string
Name of the certificate’s signing request digest algorithm. Possible values are:
−
sha256 ⟨default⟩
−
sha384
−
sha512
directory string
Path to the directory where certificates and their associated private keys are stored.
endpoint string
Name of the endpoint to use.
env table
Table of environment variables that will be accessible from hooks.
file_name_format string
Template used to build the file’s name. The template syntax is TinyTemplate. See the “STANDARDS” section for a link to the TinyTemplate specifications. If not specified, the value defined in the endpoint element, and then the global element, is used. Default is “{ name }_{ key_type }.{ file_type }.{ ext }”. Possible variables are:
ext string
File extension. Currently, only “pem” is supported.
file_type string
Contains “pk” for the private key file and “crt” for the certificate file.
key_type string
The certificate’s private key type.
name string
The certificate’s name.
hooks 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.
identifiers array
Array of tables listing the identifiers that should be included in the certificate along with the challenge to use for each one. The dns and ip fields are mutually exclusive.
challenge string
The name of the challenge to use to prove the identifier’s ownership. Possible values are:
−
dns-01
−
http-01
−
tls-alpn-01
dns string
The domain name.
env table
Table of environment variables that will be accessible from hooks.
ip string
The IP address.
key_type string
Name of the asymmetric cryptography algorithm used to generate the certificate’s key pair. Possible values are:
−
ed25519
−
ed448
−
ecdsa_p256
−
ecdsa_p384
−
ecdsa_p521
−
rsa2048 ⟨default⟩
−
rsa4096
kp_reuse boolean
Set whether or not the private key should be reused when renewing the certificate. Default is false.
name
Name of the certificate. Must be unique unless the key type is different. Will be used in logs and in the associated file’s name. The ‘*’, ‘
: ’ and ‘/’ characters will be replaced by an underscore. Default is the first identifier.
renew_delay string
Period of time between the certificate renewal and its expiration date. The format is described in the “TIME PERIODS” section. Default is the value defined in the associated endpoint.
subject_attributes table
Table where the certificate’s subject attributes are specified. Possible keys, with their RFC 4519 and X.500 equivalents, are:
ACMEd key
RFC 4519 X.500
country_name c countryName
generation_qualifier generationQualifier
given_name givenName
initials initials
locality_name l localityName
name name
organization_name o organizationName
organizational_unit_name ou organizationalUnitName
pkcs9_email_address
postal_address postalAddress
postal_code postalCode
state_or_province_name st stateOrProvinceName
street street streetAddress
surname sn surname
title title
endpoint
Array of table where each element defines a Certificate Authority (CA) which may be used to request certificates.
file_name_format string
Template used to build the file’s name. For detailed documentation, see the file_name_format directive located in the certificate element.
name string
The name the endpoint is registered under. Must be unique.
rate_limits array
Array containing the names of the HTTPS rate limits to apply.
renew_delay string
Period of time between the certificate renewal and its expiration date. The format is described in the “TIME PERIODS” section. Default is the value defined in the global section.
root_certificates array
Array containing the path to root certificates that should be added to the trust store.
tos_agreed boolean
Set whether or not the user agrees to the Terms Of Service (TOS).
url string
The endpoint’s directory URL.
global
Table containing the global configuration options.
accounts_directory string
Specify the directory where the accounts private and public keys are stored.
cert_file_group group_name|group_id string
Specify the group who will own newly-created certificates files. See chown(2) for more details.
cert_file_mode integer
Specify the permissions to use for newly-created certificates files. See chmod(2) for more details.
cert_file_user username|user_id string
Specify the user who will own newly-created certificates files. See chown(2) for more details.
certificates_directory string
Specify the directory where the certificates and their associated private keys are stored.
env table
Table of environment variables that will be accessible from hooks.
file_name_format string
Template used to build the file’s name. For detailed documentation, see the file_name_format directive located in the certificate element.
pk_file_group group_name|group_id string
Specify the group who will own newly-created private-key files. See chown(2) for more details.
pk_file_mode integer
Specify the permissions to use for newly-created private-key files. See chmod(2) for more details.
pk_file_user username|user_id string
Specify the user who will own newly-created private-key files. See chown(2) for more details.
renew_delay string
Period of time between the certificate renewal and its expiration date. The format is described in the “TIME PERIODS” section. Default is 3w.
root_certificates array
Array containing the path to root certificates that should be added to the trust store.
group
Array of table allowing to group several hooks as one. A group is considered as new hook.
hooks array
Array containing the names of the hooks that are grouped. The hooks are guaranteed to be called sequentially in the declaration order.
name string
The name the group is registered under. This name is considered as a hook name. Must be unique.
hook
Array of table where each element defines a command that will be launched at a defined point. See section “WRITING A HOOK” for more details.
allow_failure 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.
args array
Array of strings representing the command’s arguments.
cmd string
The name of the command that will be launched.
name string
The name the hook is registered under. Must be unique.
stderr string
Path to the file where the command’s standard error output if written.
stdin string
Path to the file that will be written into the command’s standard intput. Mutually exclusive with stdin_str.
stdin_str string
String that will be written into the command’s standard input. Mutually exclusive with stdin.
stdout string
Path to the file where the command’s standard output if written.
type array
Array of strings. Possible types are:
−
challenge-dns-01
−
challenge-dns-01-clean
−
challenge-http-01
−
challenge-http-01-clean
−
challenge-tls-alpn-01
−
challenge-tls-alpn-01-clean
−
file-post-create
−
file-post-edit
−
file-pre-create
−
file-pre-edit
−
post-operation
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.
In case or overlapping global option definition, the one of the last included file will be used. For example, if a file A includes files B and C and all three defines the same global option, the final value will be the one defined in file C.
Unix style globing is supported.
rate-limit
Array of table where each element defines a HTTPS rate limit.
name string
The name the rate limit is registered under. Must be unique.
number integer
Number of requests authorized withing the time period.
period string
Period of time during which a maximal number of requests is authorized. The format is described in the “TIME PERIODS” section.
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 identifier 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.
In order to allow full automation of the three above steps without imposing arbitrary restrictions or methods, 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.
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.
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.
When writing a hook, the values of args, stdin, stdin_str, stdout and stderr are considered as template strings whereas cmd is not. The template syntax is TinyTemplate. See the “STANDARDS” section for a link to the TinyTemplate specifications.
The available types and the associated template variable are described below.
challenge-dns-01
Invoked when the ownership of an identifier must be proved using the dns-01 challenge. The available template variables are:
challenge string
The name of the challenge type ⟨dns-01⟩. Mostly used in hooks with multiple types.
env array
Array containing all the environment variables.
identifier string
The identifier name whom ownership is currently being validated.
is_clean_hook bool
False
proof string
The content of the proof that must be written to a ‘TXT’ entry of the DNS zone for the ‘_acme-challenge’ subdomain.
challenge-dns-01-clean
Invoked once an identifier ownership has been proven using the 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 challenge-dns-01 hook, excepted is_clean_hook which is set to true.
challenge-http-01
Invoked when the ownership of an identifier must be proved using the http-01 challenge. The available template variables are:
challenge string
The name of the challenge type ⟨http-01⟩. Mostly used in hooks with multiple types.
env array
Array containing all the environment variables.
file_name string
Name of the file containing the proof. This is not a full path and does not include the ‘.well-known/acme-challenge/’ prefix.
identifier string
The identifier name whom ownership is currently being validated.
is_clean_hook bool
False
proof string
The content of the proof that must be written to file_name.
challenge-http-01-clean
Invoked once an identifier ownership has been proven using the 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 challenge-http-01 hook, excepted is_clean_hook which is set to true.
challenge-tls-alpn-01
Invoked when the ownership of an identifier must be proved using the tls-alpn-01 challenge. The available template variables are:
challenge string
The name of the challenge type ⟨tls-alpn-01⟩. Mostly used in hooks with multiple types.
env array
Array containing all the environment variables.
identifier string
The identifier name whom ownership is currently being validated.
identifier_tls_alpn string
The identifier name whom ownership is currently being validated, in a form suitable for the TLS ALPN challenge.
is_clean_hook bool
False
proof string
Plain-text representation of the acmeIdentifier extension that should be used in the self-signed certificate presented when a TLS connection is initiated with the ALPN extension value. acmed(8) will not generate the certificate itself since it can be done using tacd(8).
challenge-tls-alpn-01-clean
Invoked once an identifier ownership has been proven using the 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 challenge-tls-alpn-01 hook, excepted is_clean_hook which is set to true.
file-post-create
Invoked after a non-existent file created. The available template variables are the same as those available for the file-pre-create type.
file-post-edit
Invoked after an existent file modified. The available template variables are the same as those available for the file-pre-create type.
file-pre-create
Invoked before a non-existent file created. The available template variables are:
env array
Array containing all the environment variables.
file_directory string
Name of the directory where the impacted file is located.
file_name string
Name of the impacted file.
file_path string
Full path to the impacted file.
file-pre-edit
Invoked before an existent file modified. The available template variables are the same as those available for the file-pre-create type.
post-operation
Invoked at the end of the certificate request process. The available template variables are:
env array
Array containing all the environment variables.
identifiers string
Array containing the identifiers included in the requested certificate.
is_success boolean
True if the certificate request is successful.
key_type string
Name of the asymmetric cryptography algorithm used to generate the certificate’s key pair.
status string
Human-readable status. If the certificate request failed, it contains the error description.
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.
git
This hook uses git(1) to archive private keys, public keys and certificates. It is possible to customize the commit username and email by using respectively the GIT_USERNAME and GIT_EMAIL environment variables.
http-01-echo
This hook is designed to solve the http-01 challenge. For this purpose, it will write the proof into { env.HTTP_ROOT }/{ identifier }/.well-known/acme-challenge/{ file_name }.
The web server must be configured so the file http://{ identifier }/.well-known/acme-challenge/{ file_name } can be accessed from the CA.
If HTTP_ROOT is not specified, it will be set to /var/www.
tls-alpn-01-tacd-tcp
This hook is designed to solve the tls-alpn-01 challenge using tacd(8). It requires pkill(1) to support the -F option.
tacd(8) will listen on the host defined by the TACD_HOST environment variable (default is the identifier to be validated) and on the port defined by the TACD_PORT environment variable (default is 5001).
tacd(8) will store its pid into { TACD_PID_ROOT }/tacd_{ identifier }.pid. If TACD_PID_ROOT is not specified, it will be set to /run.
tls-alpn-01-tacd-unix
This hook is designed to solve the tls-alpn-01 challenge using tacd(8). It requires pkill(1) to support the -F option.
tacd(8) will listen on the unix socket { env.TACD_SOCK_ROOT }/tacd_{ identifier }.sock. If TACD_SOCK_ROOT is not specified, it will be set to /run.
tacd(8) will store its pid into { TACD_PID_ROOT }/tacd_{ identifier }.pid. If TACD_PID_ROOT is not specified, it will be set to /run.
TIME PERIODS
ACMEd uses its own time period format, which is vaguely inspired by the ISO 8601 one. Periods are formatted as PM[PM...] where M is case sensitive character representing a length and P is an integer representing a multiplayer for the following length. The authorized length are:
−
s: second
−
m: minute
−
h: hour
−
d: day
−
w: week
The PM couples can be specified multiple times and in any order.
For example, “1d42s” and “40s20h4h2s” both represents a period of one day and forty-two seconds.
TEMPLATE FORMATTERS
In addition the the formatters provided by default by TinyTemplate, ACMEd provides the following formatters:
rev_labels
Reverts the labels of a domain name (eg: “mx1.example.org” becomes “org.example.mx1” ).
FILES
/var/lib/acmed/accounts
Default accounts private and public keys directory.
/etc/acmed/acmed.toml
Default acmed(8) configuration file.
/var/lib/acmed/certs
Default certificates and associated private keys directory.
EXAMPLES
The following example defines a typical endpoint, account and certificate for a domain, several subdomains and an IP address.
[[endpoint]]
name = "example name"
url = "https://acme.example.org/directory"
tos_agreed = true
[[account]]
name = "my test account"
contacts = [
{ mailto = "[email protected]" }
]
[[certificate]]
endpoint = "example name"
account = "my test account"
identifiers = [
{ 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"},
{ ip = "203.0.113.1", challenge =
"http-01"},
]
hooks = ["git", "http-01-echo",
"tls-alpn-01-tacd-tcp",
"some-dns-01-hook"]
env.HTTP_ROOT = "/srv/http"
It is possible to use echo(1) to solve the http-01 challenge and rm(1) to clean it. mkdir(1) and chmod(1) are used to prevent issues related to file access.
[[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{{ endif }}/{ identifier
}/.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{{ endif }}/{ identifier
}/.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{{ endif }}/{ identifier
}/.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{{ endif }}/{ identifier
}/.well-known/acme-challenge/{ file_name }"
]
The hooks from the previous example can be grouped in order to reduce the number of hooks to define in the certificate.
[[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"
It is also possible to use sendmail(8) in a hook in order to notify someone when the certificate request process is done.
[[hook]]
name = "email-report"
type = ["post-operation"]
cmd = "sendmail"
args = [
"-f", "[email protected]",
"[email protected]"
]
stdin_str = """Subject: Certificate renewal
{{ if is_success }}succeeded{{ else }}failed{{ endif }} for
{ identifiers.0 }
The following
certificate has {{ if not is_success }}*not* {{ endif }}been
renewed.
identifiers: {{ for ident in identifiers }}{{ if not @first
}}, {{ endif }}{ ident }{{ endfor }}
key type: { key_type }
status: { status }"""
SEE ALSO
acmed(8), tacd(8)
STANDARDS
−
Tom Preston-Werner
,
TOML v0.5.0 ,
https://toml.io/en/v0.5.0 ,
July 2018 .
−
Brook Heisler
,
TinyTemplate ,
https://docs.rs/tinytemplate/latest/tinytemplate/syntax/index.html
.
−
M. Jones
,
JSON Web Algorithms (JWA) ,
RFC 7518 ,
May 2015 .
AUTHORS
Rodolphe Bréard ⟨[email protected]⟩ GNU Dec 19, 2022 ACMED.TOML(5)