uacme.1.txt

UACME(1)
========
:doctype: manpage
:man source:   uacme
:man version:  {revision}
:man manual:   User Commands


NAME
----
uacme - ACMEv2 client written in plain C with minimal dependencies


SYNOPSIS
--------
*uacme* [*-a*|*--acme-url* 'URL'] [*-b*|*--bits* 'BITS']
    [*-c*|*--confdir* 'DIR'] [*-d*|*--days* 'DAYS'] [*-e*|*--eab* KEYID:KEY]
    [*-f*|*--force*] [*-h*|*--hook* 'PROGRAM'] [*-i*|*--no-ari*]
    [*-l*|*--alternate* 'N' | 'FP'] [*-m*|*--must-staple*]
    [*-n*|*--never-create*] [*-o*|*--no-ocsp*] [*-r*|*--reason* CODE]
    [*-s*|*--staging*] [*-t*|*--type* *RSA*|*EC*] [*-v*|*--verbose* ...]
    [*-V*|*--version*] [*-y*|*--yes*] [*-?*|*--help*]
    *new* ['EMAIL'] | *update* ['EMAIL'] | *deactivate* | *newkey* |
    *issue* 'IDENTIFIER' ['ALTNAME' ...]] | *issue* 'CSRFILE' |
    *revoke* 'CERTFILE' ['CERTKEYFILE']


DESCRIPTION
-----------
*uacme* is a client for the ACMEv2 protocol described in RFC8555,
written in plain C with minimal dependencies (libcurl and one of
GnuTLS, OpenSSL or mbedTLS). The ACMEv2 protocol allows a
Certificate Authority (<https://letsencrypt.org> is a popular one)
and an applicant to automate the process of verification and certificate
issuance. The protocol also provides facilities for other certificate
management functions, such as certificate revocation. For more
information see <https://tools.ietf.org/html/rfc8555>


OPTIONS
-------
*-a, --acme-url* 'URL'::
    ACMEv2 server directory object 'URL'. If not specified *uacme* 
    uses one of the following:
    'https://acme-v02.api.letsencrypt.org/directory'::: production URL
    'https://acme-staging-v02.api.letsencrypt.org/directory'::: 
    staging URL (see *-s, --staging* below)

*-b, --bits* 'BITS'::
    key bit length (default 2048 for RSA, 256 for EC). Only applies
    to newly generated keys. RSA key length must be a multiple of 8
    between 2048 and 8192. EC key length must be either 256
    (*NID_X9_62_prime256v1* curve) or 384 (*NID_secp384r1* curve).

*-c, --confdir* 'CONFDIR'::
    Use configuration directory 'CONFDIR' (default '{sysconfdir}/ssl/uacme').
    The structure is as follows (multiple 'IDENTIFIERs' allowed)
        'CONFDIR/private/key.pem'::: ACME account private key
        'CONFDIR/private/IDENTIFIER/key.pem'::: certificate key for
        'IDENTIFIER'
        'CONFDIR/IDENTIFIER/cert.pem'::: certificate for 'IDENTIFIER'

*-d, --days* 'DAYS'::
    Do not reissue certificates that are still valid for longer
    than 'DAYS' (default 30). This only applies as a fallback
    if no server renewal information is available. See also
    *-i, --no-ari* and *-o, --no-ocsp*.

*-e, --eab* 'KEYID:KEY'::
    Specify RFC8555 External Account Binding credentials according
    to <https://tools.ietf.org/html/rfc8555#section-7.3.4>, in order
    to associate a new ACME account with an existing account in a
    non-ACME system such as a CA customer database.
    'KEYID' must be an ASCII string. 'KEY' must be base64url-encoded.

*-f, --force*::
    Force certificate reissuance regardless of expiration date and
    renewal information from the server.

*-h, --hook* 'PROGRAM'::
    Challenge hook program. If not specified *uacme* interacts with
    the user for every ACME challenge, printing information about the
    challenge type, token and authorization on stderr.  If specified
    *uacme* executes 'PROGRAM' (a binary, a shell script or any file that
    can be executed by the operating system) for every challenge with
    the following 5 string arguments:
        'METHOD'::: one of *begin*, *done* or *failed*.
           *begin*:::: is called at the beginning of the challenge.
           'PROGRAM' must return 0 to accept it. Any other return 
           code declines the challenge. Neither *done* nor *failed*
           method calls are made for declined challenges.
           *done*:::: is called upon successful completion of an
           accepted challenge.
           *failed*:::: is called upon failure of an accepted challenge.
        'TYPE'::: challenge type (*dns-01*, *http-01* or *tls-alpn-01*)
        'IDENT'::: The identifier the challenge refers to
        'TOKEN'::: The challenge token
        'AUTH'::: The key authorization (for *dns-01* and *tls-alpn-01*
           already converted to the base64url-encoded SHA256 digest format)

*-i, --no-ari*::
    Do not query or use the server's certificate renewal information window
    to decide whether to reissue an existing certificate. See also
    *-d, --days* and *-o, --no-ocsp*.

*-l, --alternate* 'N' | 'FP'::
    According to <https://tools.ietf.org/html/rfc8555#section-7.4.2>
    the server MAY provide one or more additional certificate download URLs,
    each pointing to alternative certificate chains starting with the same
    end-entity certificate. This option allows selecting one such chain
    in one of two ways. A positive integer 'N' makes *uacme* select the Nth
    alternative chain in the order presented by the server.
    A colon (':') separated list of two or more 2-digit hexadecimal numbers
    'FP' makes *uacme* select the first alternative chain containing either a
    certificate whose SHA256 fingerprint begins with 'FP', or a certificate
    in which the Authority Key Identifier extension contains a keyIdentifier
    field beginning with 'FP'.
    In all cases *uacme* falls back to the main certificate URL if it cannot
    match an alternative chain or the download thereof fails.

*-m, --must-staple*::
    Request certificates with the RFC7633 Certificate Status Request
    TLS Feature Extension, informally also known as "OCSP Must-Staple".
    This option is ignored when using an externally supplied Certificate
    Signing Request file (see USAGE below).

*-n, --never-create*::
    By default *uacme* creates directories/keys if they do not exist.
    When this option is specified *uacme* never does so and instead
    exits with an error if anything required is missing.

*-o, --no-ocsp*::
    When this flag is *not* specified and the certificate has an
    Authority Information Access extension with an OCSP server location
    according to <https://tools.ietf.org/html/rfc5280#section-4.2.2.1> 
    *uacme* makes an OCSP request to the server; if the certificate is
    reported as revoked *uacme* forces reissuance regardless of the
    expiration date. See also *-d, --days*.

*-r, --reason* 'CODE'::
    Use 'CODE' (default 0) as reason code in revocation requests. A list
    of values is at <https://tools.ietf.org/html/rfc5280#section-5.3.1>.

*-s, --staging*::
    Use Let's Encrypt staging URL for testing. This only works if
    *-a, --acme-url* is *NOT* specified.

*-t, --type*='RSA' | 'EC'::
    Key type, either RSA or EC. Only applies to newly generated keys.
    The bit length can be specified with *-b, --bits*.

*-v, --verbose*::
    By default *uacme* only produces output upon errors or when user
    interaction is required. When this option is specified *uacme*
    prints information about what is going on on stderr. This option
    can be specified more than once to increase verbosity.

*-V, --version*::
    Print program version on stderr and exit.

*-y, --yes*::
    Autoaccept ACME server terms (if any) upon new account creation.

*-?, --help*::
    Print a brief usage text on stderr and exit.


USAGE
-----

*uacme* ['OPTIONS' ...] *new* ['EMAIL']::
    Create a new ACME account with optional 'EMAIL' contact. If the
    account private key does not exist at 'CONFDIR/private/key.pem'
    a new key is generated unless *-n, --never-create* is specified.
    A valid account must be created *before* any other operation can
    succeed (with the exception of certificate revocation requests
    signed by the certificate private key).
    Any certificate issued by the ACME server is associated with a
    single account. An account can be associated with multiple
    certificates, subject of course to the rate limits imposed by the
    ACME server.

*uacme* ['OPTIONS' ...] *update* ['EMAIL']::
    Update the 'EMAIL' associated with the ACME account corresponding to
    the account private key. If 'EMAIL' is not specified the account
    contact email is removed.

*uacme* ['OPTIONS' ...] *deactivate*::
    Deactivate the ACME account corresponding to the account private
    key. *WARNING* this action is irreversible. Users may wish to do
    this when the account key is compromised or decommissioned.
    A deactivated account can no longer request certificate issuances
    and revocations or access resources related to the account.

*uacme* ['OPTIONS' ...] *newkey*::
    Change the ACME account private key. If the new account private
    key does not exist at 'CONFDIR/private/newkey.pem' it is generated
    unless *-n, --never-create* is specified. The new key is then
    submitted to the server and if the operation succeeds the old key
    is hardlinked to 'CONFDIR/private/key-TIMESTAMP.pem' before
    renaming 'CONFDIR/private/newkey.pem' to 'CONFDIR/private/key.pem'.

*uacme* ['OPTIONS' ...] *issue* 'IDENTIFIER' ['ALTNAME' ...]::
    Issue a certificate for 'IDENTIFIER' with zero or more 'ALTNAMEs'.
    If a certificate is already available at 'CONFDIR/IDENTIFIER/cert.pem'
    for the specified 'IDENTIFIER' and 'ALTNAMEs' and is still valid for
    longer than 'DAYS' no action is taken unless *-f, --force* is specified
    or *-o, --no-ocsp* is *not* specified and the certificate is reported
    as revoked by the OCSP server.  The new certificate is saved to
    'CONFDIR/IDENTIFIER/cert.pem'.  If the certificate file already exists
    it is hardlinked to 'CONFDIR/IDENTIFIER/cert-TIMESTAMP.pem' before
    overwriting.  The private key for the certificate is loaded from
    'CONFDIR/private/IDENTIFIER/key.pem'. If no such file exists,
    a new key is generated unless *-n, --never-create* is specified.
    Wildcard 'IDENTIFIERs' or 'ALTNAMEs' are dealt with correctly, as long
    as the ACME server supports them; note that any such wildcards are
    automatically removed from the configuration subdirectory name:
    for example a certificate for '*.test.com' is saved to
    'CONFDIR/test.com/cert.pem'.
    IP address 'IDENTIFIERs' and 'ALTNAMEs' are also supported according to
    <https://tools.ietf.org/html/rfc8738#section-3>

*uacme* ['OPTIONS' ...] *issue* 'CSRFILE'::
    Issue a certificate based on a RFC2986 Certificate Signing Request
    contained in 'CSRFILE', which must be in PEM format. In this mode
    of issuance *uacme* neither needs nor generates the certificate private
    key, but it is of course the responsibility of the user to ensure that
    the CSR is constructed and signed appropriately.
    If a certificate file 'CSRBASE-cert.pem' (where 'CSRBASE' is obtained
    by stripping the extension, if any, from 'CSRFILE') is already available
    in the same directory containing 'CSRFILE', and is still valid for longer
    than 'DAYS' no action is taken unless *-f, --force* is specified or
    *-o, --no-ocsp* is *not* specified and the certificate is reported as
    revoked by the OCSP server.  If the certificate file already exists it
    is hardlinked to 'BASENAME-cert-TIMESTAMP.pem' before overwriting.
    Wildcard identifiers in the CSR are dealt with correctly, as long as
    the ACME server supports them.  IP addresses are also supported
    according to <https://tools.ietf.org/html/rfc8738#section-3>

*uacme* ['OPTIONS' ...] *revoke* 'CERTFILE' ['CERTKEYFILE']::
    Revoke the certificate stored in 'CERTFILE'. The revocation request
    is signed with the private key of either the certificate, when 
    'CERTKEYFILE' is specified; or the ACME account associated with the
    certificate, when only 'CERTFILE' is specified. In the first instance
    the account key and the configuration directory are not required.
    If successful 'CERTFILE' is renamed to 'revoked-TIMESTAMP.pem'.
    The reason code in the revocation request defaults to 0 but it
    can be specified by the user with *-r, --reason*.


ENVIRONMENT
-----------
*UACME_CAINFO*::
    String naming a file holding one or more CA certificates to verify
    the ACME server with.

*UACME_CAPATH*::
    String naming a directory holding multiple CA certificates to verify
    the ACME server with. If libcurl is built against OpenSSL, the certificate
    directory must be prepared using the OpenSSL c_rehash utility.

*UACME_DNS_SERVERS*::
    Comma separated list of DNS servers to be used instead of the system
    default. The format of the dns servers option is
    'host[:port][,host[:port]]...'

*UACME_INTERFACE*::
    String setting the interface name to use as outgoing network interface.
    The name can be an interface name, an IP address, or a hostname.
    If you prefer one of these, you can use the following special prefixes:

    'if!<name>'::: Interface name
    'host!<name>'::: IP address or hostname
    'ifhost!<interface>!<host>'::: Interface name and IP address or hostname 

*UACME_PROXY*::
    String holding the proxy hostname or dotted numerical IP address.
    A numerical IPv6 address must be written within [brackets].
    To specify port number in this string, append :[port] to the end of
    the host name. If not specified, default to using port 1080.
    The proxy string may be prefixed with [scheme]:// to specify which
    kind of proxy is used (http://, https://, socks4://, socks4a://,
    socks5://, socks5h://).
    The proxy can also be specified with its associated credentials like
    for ordinary URLs in the style: 'scheme://username:password@hostname'


HOOK ENVIRONMENT
----------------
The following environment variables are exported for use by the hook program:

*UACME_CONFDIR*::
    Path to 'CONFDIR', see *-c, --confdir*

*UACME_VERBOSE*::
    Verbosity, see *-v, --verbose*

*UACME_METHOD*, *UACME_TYPE*, *UACME_IDENT*, *UACME_TOKEN*, *UACME_AUTH*::
    Copies of the hook program arguments, see *-h, --hook*


EXIT STATUS
-----------
*0*::
    Success

*1*::
    Certificate not reissued because it is still current

*2*::
    Failure (syntax or usage error; configuration error; 
    processing failure; unexpected error).


EXAMPLE HOOK SCRIPT
-------------------

The 'uacme.sh' hook script included in the distribution can be used
to automate the certificate issuance with 'http-01' challenges,
provided a web server for the domain being validated runs on the 
same machine, with webroot at /var/www

    #!/bin/sh
    CHALLENGE_PATH=/var/www/.well-known/acme-challenge
    ARGS=5
    E_BADARGS=85
    
    if test $# -ne "$ARGS"
    then
        echo "Usage: $(basename "$0") method type ident token auth" 1>&2
        exit $E_BADARGS
    fi
    
    METHOD=$1
    TYPE=$2
    IDENT=$3
    TOKEN=$4
    AUTH=$5
    
    case "$METHOD" in
        "begin")
            case "$TYPE" in
                http-01)
                    echo -n "${AUTH}" > "${CHALLENGE_PATH}/${TOKEN}"
                    exit $?
                    ;;
                *)
                    exit 1
                    ;;
            esac
            ;;
        "done"|"failed")
            case "$TYPE" in
                http-01)
                    rm "${CHALLENGE_PATH}/${TOKEN}"
                    exit $?
                    ;;
                *)
                    exit 1
                    ;;
            esac
            ;;
        *)
            echo "$0: invalid method" 1>&2 
            exit 1
    esac


BUGS
----
If you believe you have found a bug, please create a new issue
at https://github.com/ndilieto/uacme/issues with any applicable
information. 

SEE ALSO
--------
*ualpn*(1)

AUTHOR
------
*uacme* was written by Nicola Di Lieto

COPYRIGHT
---------
Copyright (C) 2019-2024 Nicola Di Lieto <nicola.dilieto@gmail.com>

This file is part of *uacme*.

*uacme* is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

*uacme* is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.