Crypt::LE (ZeroSSL project) - Let's Encrypt client and library in Perl for getting free SSL certificates (inc. generating RSA/ECC keys and CSRs). HTTP/DNS verification is supported out of the box, easily extended with plugins.
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README.md

Crypt-LE

This module provides the functionality necessary to use Let's Encrypt API and generate free SSL certificates for your domains. It can also be used to generate private RSA (and from version 0.20 also ECC) keys or Certificate Signing Requests without resorting to openssl command line. Crypt::LE is shipped with a self-sufficient client for obtaining SSL certificates - le.pl.

Both ACME v1 and ACME v2 protocols and wildcard certificate issuance are supported.

The client + library package is codenamed ZeroSSL with the project homepage at https://ZeroSSL.com

Note: If you do not need the automation and the flexibility this package offers, and just want to get a free SSL certificate without installing anything, you can do that online with Free SSL Certificate Wizard (works on PC and mobiles, supports different languages: EN, DE, FR, ES, RU, IT and also supports wildcard certificates issuance).

COMPATIBILITY

  • The code has been successfully tested on more than 500 combinations of OS and Perl versions. It should install and run fine on Linux, FreeBSD, NetBSD, etc. It also works on Mac OS X and Windows (tested with ActiveState and Strawberry Perl).

  • If you are a Windows user, you can download portable Win32/Win64 binaries (they work even on Windows XP and require NO installation).

  • In addition, you can use the latest Docker Image (lightweight non-root container).

Table of Contents

REQUIREMENTS

With Linux systems there are just 3 essential things which should be in place for the package to be successfully installed: "gcc", "make" and the SSL development package. The SSL development package name differs depending on Linux distribution and it can be either "libssl-dev" or "openssl-devel". See https://zerossl.com/installation.html for more details.

With Windows you don't have to install anything if you want to use Windows binaries - self-sufficient and portable. Otherwise you just need to install Perl. Actually, in case of Strawberry Perl you don't have to install Perl either - it is enough to download the portable version of it, unzip and then use "cpanm" to install Crypt::LE.

INSTALLATION

With CPANminus

cpanm Crypt::LE

With CPAN

cpan -i Crypt::LE

Manual installation

perl Makefile.PL
make
make test
make install

Windows installation (with Strawberry Perl)

cpanm -f Log::Log4perl
cpanm Crypt::LE

Note: On Windows current version of the logging module needs to be installed with -f flag first if Strawberry Perl is used.

CLIENT

With le.pl you should be able to quickly get your SSL certificates issued. Run it without parameters to see how it is used or with --help for an extended help and examples. The client supports 'http' and 'dns' challenges out of the box.

Important: By default all your actions are run against the test server, which behaves exactly as the live one, but produces certificates not trusted by the browsers. Once you have tested the process and want to get an actual trusted certificate, always append --live parameter to the command line.

Usage example:

le.pl --key account.key --email "my@email.address" --csr domain.csr --csr-key domain.key --crt domain.crt --domains  "www.domain.ext,domain.ext" --generate-missing

That will generate an account key and a CSR if they are missing. If any of those files exists, they will just be loaded, so it is safe to re-run the client.

Please note that --email parameter is only used for the initial registration. To update it later you can use --update-contacts option. Even though it is optional, you may want to have your email registered to receive certificate expiration notifications.

To use HTTP verification and have challenge files created/removed automatically, you can use --path and --unlink parameters:

le.pl --key account.key --email "my@email.address" --csr domain.csr --csr-key domain.key --crt domain.crt --domains "www.domain.ext,domain.ext" --generate-missing --unlink --path /some/path/.well-known/acme-challenge

If www.domain.ext and domain.ext use different "webroots", you can specify those in --path parameter, as a comma-separated list as follows:

le.pl --key account.key --email "my@email.address" --csr domain.csr --csr-key domain.key --crt domain.crt --domains "www.domain.ext,domain.ext" --generate-missing --unlink --path /a/.well-known/acme-challenge,/b/.well-known/acme-challenge

Please note that with multiple webroots specified, the amount of those should match the amount of domains listed. They will be used in the same order as the domains given and all of those folders should be writable.

To use DNS verification of domain ownership, you can use --handle-as parameter:

 le.pl ... --handle-as dns

For more examples, logging configuration and all available parameters overview use --help:

le.pl --help

WILDCARD CERTIFICATES SUPPORT

To issue a wildcard certificate, use DNS verification and specify the domain in the following format: *.some.domain.

 le.pl ... --domains "*.some.domain" --handle-as dns --api 2

Please note that at the moment wildcards are only supported by the v2.0 of the API and they can only be issued if DNS verification is used.

Important - if you are issuing a wildcard certificate and also want a so-called "naked domain" ("some.domain") to be covered, list both of those names in the domains parameter. You will then need to create two TXT records with identical names but different values - this is normal and this is how you should create them.

 le.pl ... --domains "*.some.domain, some.domain" --handle-as dns --api 2

PFX/P12 (IIS) SUPPORT

Windows binaries include export functions into PFX/P12 format, which is normally required by IIS. The export (in addition to saving certificates in PEM format) can be activated by specifying a PFX password with --export-pfx option.

  le.pl ... --export-pfx "mypassword"

Note: This fuction does NOT require OpenSSL or any PFX conversion tools to be installed on your machine - it is supported internally by the client.

By default, exported PFX file will be seen as "ZeroSSL exported" under the "Friendly Name" column of the Certificate Management Console. If you want to specify your own arbitrary string instead, use --tag-pfx parameter.

  le.pl ... --export-pfx "mypassword" --tag-pfx "My own Friendly Name"

NB: If you are receiving an error mentioning PKCS12 during an attemp to export to PFX, please ensure that the domain key which you have specified with --csr-key option is indeed a private key in PEM format (with -----BEGIN and -----END lines around it). If it is a key exported via MMC in Windows for example, you may need to export the key and remove the passphrase from it before it can be used, for example as mentioned in this guide. If the key has been generated by the client itself, you should see no errors, as it is already in the expected format.

IDN (INTERNATIONALIZED DOMAIN NAMES) SUPPORT

If you are using IDN (Internationalized Domain Names) and generating a certificate for those, you can either encode those into "punycode" form by yourself, or let the client do that for you. Please note that for the conversion to work properly you need to have correct locale settings on your system. For Linux-based systems you can check that with the "locale" command, for Windows make sure that "System locale" in the Control Panel is set correctly.

RENEWALS

To RENEW your existing certificate use the same command line as you used for issuing the certificate, with one additional parameter:

   --renew XX, where XX is the number of days left until certificate expiration.

If client detects that it is XX or fewer days left until certificate expiration, then (and only then) the renewal process will be run, so the script can be safely put into crontab to run on a daily basis if needed.

The amount of days left is checked by either of two methods:

  • If the certificate (which name is used with --crt parameter) is available locally, then it will be loaded and checked.
  • If the certificate is not available locally (for example if you moved it to another server), then an attempt to connect to the domains listed in --domains or CSR will be made until the first successful response is received. The peer certificate will be then checked for expiration.

CONTACT DETAILS UPDATES

If you would like to receive expiration notifications for your domain, you can specify --email parameter and an appropriate email address during the initial registration of the account. Later, shall you want to change your email or specify more than one, you can use --update-contacts parameter to update your contact information. For example:

le.pl --key account.key --update-contacts "one@email.address, another@email.address" --live

To reset your contact details, please specify "none" as a value, as follows:

le.pl --key account.key --update-contacts "none" --live

PLUGINS

Both the library and the client can be easily extended with custom plugins to handle Let's Encrypt challenges (both pre- and post-verification). See Crypt::LE::Challenge::Simple module as an example of such plugin.

The client application can also be easily extended with modules handling process completion. See Crypt::LE::Complete::Simple module as an example of such plugin.

Client options related to plugins are:

  • --handle-with
  • --handle-params
  • --handle-as
  • --complete-with
  • --complete-params

Please note that parameters for --handle-params and --complete-params are expected to be valid JSON documents or to point to files containing valid JSON documents.

Example of running the client with plugins (you can modify the source code of the provided Crypt::LE::Challenge::Simple and Crypt::LE::Complete::Simple):

le.pl --key account.key --email "my@email.address" --csr domain.csr --csr-key domain.key --crt domain.crt --domains "www.domain.ext,domain.ext" --generate-missing --handle-with Crypt::LE::Challenge::Simple --complete-with Crypt::LE::Complete::Simple

CUSTOM LOGGING

Client uses Log::Log4perl module for logging. You can easily configure it to log into file, database, syslog, etc. Logger object is available to plugins which are called from the client and to the library itself. Below is an example of a logging configuration file to log both to screen and into le.log file:

 log4perl.rootLogger=DEBUG, File, Screen
 log4perl.appender.File = Log::Log4perl::Appender::File
 log4perl.appender.File.filename = le.log
 log4perl.appender.File.mode = append
 log4perl.appender.File.layout = PatternLayout
 log4perl.appender.File.layout.ConversionPattern = %d [%p] %m%n
 log4perl.appender.File.utf8 = 1
 log4perl.appender.Screen = Log::Log4perl::Appender::Screen
 log4perl.appender.Screen.layout = PatternLayout
 log4perl.appender.Screen.layout.ConversionPattern = %d [%p] %m%n
 log4perl.appender.Screen.utf8 = 1

Save the configuration into some file and then run le.pl with --log-config parameter specifying that configuration file name, for those settings to take effect.

CUSTOM EXIT CODES

By default the client application produces a limited set of exit codes - 1 on help or unknown parameters and 255 in case of other errors. Additionally the case of attempting a renewal too early is not considered an error. This behaviour can be changed to assign custom exit codes to different errors (including setting an error code for an early renewal).

If you wish to change an exit code for a particular error, you need to find the associated message first and then assign some code via a config file. For example, say you are receiving an error message saying "Could not read the certificate file." and you want to assign an error code of 200 to it. If you you add --debug flag to the command line, that same error message would look as "[ CERTIFICATE_FILE_READ ] Could not read the certificate file." If now you create a configuration file as shown below, running the same command as before with --config name_of_your_configuration_file will change the exit code for that error to 200:

[errors]
CERTIFICATE_FILE_READ = 200

SUPPORT AND DOCUMENTATION

After installing, you can find documentation for this module with the perldoc command.

perldoc Crypt::LE

You can also look for information at:

For feedback or custom development requests see:

NOTES

Crypt::LE has been initially created over weekend, when I noticed that some of my previously bought certificates are about to expire soon enough. The initial goal was to make this work, make it easy to use and possibly remove the need to use openssl command line. It may contain some (hopefully minor) bugs, so feel free to submit a bug report.

If you'd like to contribute a custom plugin, for example to support automatic DNS records creation and removal via API of certain DNS providers (or your registrar), feel free to create a module under Crypt::LE::Challenge:: namespace and either upload it to CPAN or submit a pull request.

In the former case please specify a dependency from Crypt::LE of at least version 0.11 in your Makefile.

In the latter case please be aware that your module might be uploaded to CPAN later (unless you object) and might be uploaded separately rather than as a part of Crypt::LE (this might happen if you are using dependencies not necessarily required for the rest of Crypt::LE package).

You can also contribute the completion-handling modules under Crypt::LE::Complete:: namespace, for example to scp the domain key and certificate to another host or to send an email about successful certificate renewal.

LICENSE AND COPYRIGHT

Copyright (C) 2016-2018 Alexander Yezhov

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.