| lacme(1) | lacme(1) |
NAME¶
lacme - ACME client written with process isolation and minimal privileges in mindSYNOPSIS¶
lacme [--config=FILENAME] [--socket=PATH] [OPTION ...] COMMAND [ARGUMENT ...]DESCRIPTION¶
lacme is a small ACME client written with process isolation and minimal privileges in mind. It is divided into four components, each with its own executable:- 1.
- A lacme-accountd(1) process to manage the account key and issue SHA-256 signatures needed for each ACME command. (This process binds to a UNIX-domain socket to reply to signature requests from the ACME client.) One can use the UNIX-domain socket forwarding facility of OpenSSH 6.7 and later to run lacme-accountd(1) and lacme on different hosts. Alternatively, the lacme-accountd(1) process can be spawned by the “master” lacme process below; in that case, the two processes communicate through a socket pair.
- 2.
- A “master” lacme process, which runs as root and is the only component with access to the private key material of the server keys. It is used to fork the ACME client (and optionally the ACME webserver) after dropping root privileges. For certificate issuances (new-cert command), it also generates Certificate Signing Requests, then verifies the validity of the issued certificate, and optionally reloads or restarts services when the notify option is set.
- 3.
- An actual ACME client (specified with the command option of the [client] section of the configuration file), which builds ACME commands and dialogues with the remote ACME server. Since ACME commands need to be signed with the account key, the “master” lacme process passes the lacme-accountd(1) UNIX-domain socket to the ACME client: data signatures are requested by writing the data to be signed to the socket.
- 4.
- For certificate issuances (new-cert command), an optional webserver (specified with the command option of the [webserver] section of the configuration file), which is spawned by the “master” lacme process when no service is listening on the HTTP port. (The only challenge type currently supported by lacme is http-01, which requires a webserver to answer challenges.) That webserver only processes GET and HEAD requests under the /.well-known/acme-challenge/ URI. By default some iptables (8) rules are automatically installed to open the HTTP port, and removed afterwards.
COMMANDS¶
- lacme [--agreement-uri=URI] new-reg [CONTACT ...]
- Register the account key managed by lacme-accountd(1). A list of CONTACT information (such as maito: URIs) can be specified in order for the server to contact the client for issues related to this registration (such as notifications about server-initiated revocations).
--agreement-uri= can be used to specify a URI referring to a subscriber agreement or terms of service provided by the server; adding this options indicates the client's agreement with the referenced terms. Note that the server might require the client to agree to subscriber agreement before performing any further actions.
If the account key is already registered, lacme prints the URI of the existing registration and aborts.
- lacme [--agreement-uri=URI] reg=URI [ CONTACT ...]
- Dump or edit the registration URI (relative to the ACME server URI, which is specified with the server option of the [client] section of the configuration file).
When specified, the list of CONTACT information and the agreement URI are sent to the server to replace the existing values.
- lacme [--config-certs=FILE] new-cert [SECTION ...]
- Read the certificate configuration FILE (see the certificate configuration file section below for the configuration options), and request new Certificate Issuance for each of its sections (or the given list of SECTIONs).
- lacme revoke-cert FILE [FILE ...]
- Request that the given certificate(s) FILE(s) be revoked. For this command, lacme-accountd(1) can be pointed to either the account key or the server's private key.
GENERIC OPTIONS¶
- --config=filename
- Use filename as configuration file. See the configuration file section below for the configuration options.
- --socket=path
- Use path as the lacme-accountd(1) UNIX-domain socket to connect to for signature requests from the ACME client. lacme aborts if path is readable or writable by other users, or if its parent directory is writable by other users. This command-line option overrides the socket option of the [client] section of the configuration file. Moreover this option is ignored when the configuration file has an [accountd] section; in that case lacme spawns lacme-accountd(1), and the two processes communicate through a socket pair.
- -h, --help
- Display a brief help and exit.
- -q, --quiet
- Be quiet.
- --debug
- Turn on debug mode.
CONFIGURATION FILE¶
If --config= is not given, lacme uses the first existing configuration file among ./lacme.conf, $XDG_CONFIG_HOME/lacme/lacme.conf (or ~/.config/lacme/lacme.conf if the XDG_CONFIG_HOME environment variable is not set), and /etc/lacme/lacme.conf. Valid options are:DEFAULT SECTION¶
- config-certs
- For certificate issuances (new-cert command), specify the space-separated list of certificate configuration files or directories to use (see the certificate configuration file section below for the configuration options).
Paths not starting with / are relative to the directory name of the configuration filename. The list of files and directories is processed in order, with the later items taking precedence. Files in a directory are processed in lexicographic order, only considering the ones with suffix .conf.
Default: lacme-certs.conf lacme-certs.conf.d/.
[client] SECTION¶
This section is used for configuring the ACME client (which takes care of ACME commands and dialogues with the remote ACME server).- socket
- See --socket=. Default: $XDG_RUNTIME_DIR/S.lacme if the XDG_RUNTIME_DIR environment variable is set.
- user
- The username to drop privileges to (setting both effective and real uid). Preserve root privileges if the value is empty (not recommended). Default: nobody.
- group
- The groupname to drop privileges to (setting both effective and real gid, and also setting the list of supplementary gids to that single group). Preserve root privileges if the value is empty (not recommended). Default: nogroup.
- command
- Path to the ACME client executable. Default: /usr/lib/lacme/client.
- server
- Root URI of the ACME server. Default: https://acme-v01.api.letsencrypt.org/.
- timeout
- Timeout in seconds after which the client stops polling the ACME server and considers the request failed. Default: 10.
- SSL_verify
- Whether to verify the server certificate chain. Default: Yes.
- SSL_version
- Specify the version of the SSL protocol used to transmit data.
- SSL_cipher_list
- Specify the cipher list for the connection, see ciphers(1ssl) for more information.
[webserver] SECTION¶
This section is used for configuring the ACME webserver.- listen
- Specify the local address to listen on, in the form ADDRESS[:PORT]. If ADDRESS is enclosed with brackets `['/‘]' then it denotes an IPv6; an empty ADDRESS means 0.0.0.0. Default: :80.
- challenge-directory
- If a webserver is already running, specify a non-existent directory under which the webserver is configured to serve GET requests for challenge files under /.well-known/acme-challenge/ (for each virtual hosts requiring authorization) as static files. Default: /var/www/acme-challenge.
- user
- The username to drop privileges to (setting both effective and real uid). Preserve root privileges if the value is empty (not recommended). Default: www-data.
- group
- The groupname to drop privileges to (setting both effective and real gid, and also setting the list of supplementary gids to that single group). Preserve root privileges if the value is empty (not recommended). Default: www-data.
- command
- Path to the ACME webserver executable. Default: /usr/lib/lacme/webserver.
- iptables
- Whether to automatically install iptables(8) rules to open the ADDRESS[:PORT] specified with listen. Theses rules are automatically removed once lacme exits. Default: Yes.
[accountd] SECTION¶
This section is used for configuring the lacme-accountd(1) process. If the section (including its header) is absent or commented out, lacme connects to an existing UNIX-domain socket bound by a running lacme-accountd(1) process.- user
- The username to drop privileges to (setting both effective and real uid). Preserve root privileges if the value is empty.
- group
- The groupname to drop privileges to (setting both effective and real gid, and also setting the list of supplementary gids to that single group). Preserve root privileges if the value is empty.
- command
- Path to the lacme-accountd(1) executable. Default: /usr/bin/lacme-accountd.
- config
- Path to the lacme-accountd(1) configuration file. Default: /etc/lacme/lacme-accountd.conf.
- privkey
- The (private) account key to use for signing requests. See lacme-accountd(1) for details.
- quiet
- Be quiet. Possible values: Yes/No.
CERTIFICATE CONFIGURATION FILE¶
For certificate issuances (new-cert command), a separate file is used to configure paths to the certificate and key, as well as the subject, subjectAltName, etc. to generate Certificate Signing Requests. Each section denotes a separate certificate issuance. Valid options are:- certificate
- Where to store the issued certificate (in PEM format). At least one of certificate or certificate-chain is required.
- certificate-chain
- Where to store the issued certificate, concatenated with the content of the file specified specified with the CAfile option (in PEM format). At least one of certificate or certificate-chain is required.
- certificate-key
- Path the service's private key. This option is required. The following command can be used to generate a new 4096-bits RSA key in PEM format with mode 0600:
-
openssl genrsa 4096 | install -m0600 /dev/stdin /path/to/srv.key
- min-days
- For an existing certificate, the minimum number of days before its expiration date the section is considered for re-issuance. Default: 10.
- CAfile
- Path to the issuer's certificate. This is used for certificate-chain and to verify the validity of each issued certificate. Specifying an empty value skip certificate validation. Default: /usr/share/lacme/lets-encrypt-x3-cross-signed.pem.
- hash
- Message digest algorithm to sign the Certificate Signing Request with.
- keyUsage
- Comma-separated list of Key Usages, see x509v3_config(5ssl).
- subject
- Subject field of the Certificate Signing Request, in the form /type0=value0/type1=value1/type2=.... This option is required.
- subjectAltName
- Comma-separated list of Subject Alternative Names, in the form type0:value1,type1:value1,type2:... The only type currently supported is DNS, to specify an alternative domain name.
- chown
- An optional username[:groupname] to chown the issued certificate and certificate-chain to.
- chmod
- An optional octal mode to chmod the issued certificate and certificate-chain to.
- notify
- Command to pass the the system's command shell (/bin/sh -c) after successful installation of the certificate and/or certificate-chain.
EXAMPLES¶
-
~$ sudo lacme new-reg mailto:noreply@example.com ~$ sudo lacme reg=/acme/reg/123456 --agreement-uri=https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf ~$ sudo lacme new-cert ~$ sudo lacme revoke-cert /path/to/server/certificate.pem
BUGS AND FEEDBACK¶
Bugs or feature requests for lacme should be filed with the Debian project's bug tracker at <https://www.debian.org/Bugs/>.SEE ALSO¶
lacme-accountd(1)AUTHORS¶
Guilhem Moulin (mailto:guilhem@fripost.org).| December 2015 |