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Crypt::SSLeay - OpenSSL support for LWP

Do you need Crypt::SSLeay?

Since version 6.02, LWP depends on LWP::Protocol::https which pulls in IO::Socket::SSL which is then automatically used by LWP::UserAgent unless you explicitly override it. So, you might no longer need Crypt::SSLeay. IO::Socket::SSL is preferable anyway because it allows hostname verification which Crypt::SSLeay does not support.

At this point, Crypt::SSLeay is maintained to support existing software that already depends on it. However, it is possible that your software does not really depend on Crypt::SSLeay, only on the ability of LWP::UserAgent to communicate with sites over SSL/TLS.

If you have both Crypt::SSLeay and IO::Socket::SSL installed, and would like to force LWP::UserAgent to use Crypt::SSLeay, you can use:

use Net::HTTPS;
$Net::HTTPS::SSL_SOCKET_CLASS = 'Net::SSL';
use LWP::UserAgent;

or

local $ENV{PERL_NET_HTTPS_SSL_SOCKET_CLASS} = 'Net::SSL';
use LWP::UserAgent;

or

use Net::SSL;
use LWP::UserAgent;

OpenSSL Heartbleed Bug

perl Makefile.PL will show a warning if the version of OpenSSL against which you are building Crypt::SSLeay seems vulnerable to the Heartbleed Bug. See my blog post Is a strong caution about Heartbleed worth the disruption to distributions with a declared dependency on Crypt::SSLeay? for the reasoning behind this.

Synopsis

use Net::SSL;
use LWP::UserAgent;

my $ua  = LWP::UserAgent->new(
    ssl_opts => { verify_hostname => 0 },
);

my $response = $ua->get('https://www.example.com/');
print $response->content, "\n";

Description

This Perl module provides support for the HTTPS protocol under LWP, to allow an LWP::UserAgent object to perform GET, HEAD and POST requests. Please see LWP for more information on POST requests.

The Crypt::SSLeay package provides Net::SSL, which is loaded by LWP::Protocol::https for https requests and provides the necessary SSL glue.

This distribution also makes following deprecated modules available:

Crypt::SSLeay::CTX
Crypt::SSLeay::Conn
Crypt::SSLeay::X509

Work on Crypt::SSLeay has been continued only to provide https support for the LWP (libwww-perl) libraries.

Environment Variables

The following environment variables change the way Crypt::SSLeay and Net::SSL behave.

Specify SSL Socket Class

$ENV{PERL_NET_HTTPS_SSL_SOCKET_CLASS}

can be used to instruct LWP::UserAgent to use Net::SSL for HTTPS support rather than IO::Socket::SSL.

Proxy Support

$ENV{HTTPS_PROXY} = 'http://proxy_hostname_or_ip:port';

Proxy Basic Authentication

$ENV{HTTPS_PROXY_USERNAME} = 'username';
$ENV{HTTPS_PROXY_PASSWORD} = 'password';

SSL Diagnostics and Debugging

$ENV{HTTPS_DEBUG} = 1;

Default SSL Version

$ENV{HTTPS_VERSION} = '3';

Client Certificate Support

$ENV{HTTPS_CERT_FILE} = 'certs/notacacert.pem';
$ENV{HTTPS_KEY_FILE}  = 'certs/notacakeynopass.pem';

CA cert peer verification

$ENV{HTTPS_CA_FILE}   = 'certs/ca-bundle.crt';
$ENV{HTTPS_CA_DIR}    = 'certs/';

Client PKCS12 cert support

$ENV{HTTPS_PKCS12_FILE}     = 'certs/pkcs12.pkcs12';
$ENV{HTTPS_PKCS12_PASSWORD} = 'PKCS12_PASSWORD';

Installation

OpenSSL

You must have OpenSSL installed before compiling this module. You can get the latest OpenSSL package from OpenSSL.org. We no longer support pre-2000 versions of OpenSSL.

If you are building OpenSSL from source, please follow the directions included in the source package.

Crypt::SSLeay via Makefile.PL

Makefile.PL accepts the following command line arguments:

incpath

Path to OpenSSL headers. Can also be specified via $ENV{OPENSSL_INCLUDE}. If the command line argument is provided, it overrides any value specified via the environment variable. Of course, you can ignore both the command line argument and the environment variable, and just add the path to your compiler specific environment variable such as CPATH or INCLUDE etc.

libpath

Path to OpenSSL libraries. Can also be specified via $ENV{OPENSSL_LIB}. If the command line argument is provided, it overrides any value specified by the environment variable. Of course, you can ignore both the command line argument and the environment variable and just add the path to your compiler specific environment variable such as LIBRARY_PATH or LIB etc.

live-tests

Use --live-tests to request tests that try to connect to an external web site, and "--no-live_tests" to prevent such tests from running. If you run Makefile.PL interactively, and this argument is not specified on the command line, you will be prompted for a value.

Default is false.

static

Boolean. Default is false. TODO: How is this even supposed to work?

verbose

Boolean. Default is false. If you pass --verbose on the command line, both "Devel::CheckLib" and "ExtUtils::CBuilder" instances will be configured to echo what they are doing.

If everything builds OK, but you get failures when during tests, ensure that LD_LIBRARY_PATHis pointing to the location where the correct shared libraries are located.

Crypt::SSLeay

The latest Crypt::SSLeay can be found at your nearest CPAN, as well as on metacpan.

Once you have downloaded and extracted it, Crypt::SSLeay installs easily using the standard build process:

perl Makefile.PL
make
make test
make install

Alternatively, you can use cpanm:

cpanm Crypt::SSLeay

If you have OpenSSL headers and libraries in nonstandard locations, you can use

$ perl Makefile.PL --incpath=... --libpath=...

If you would like to use "cpanm" with such custom locations, you can do

$ OPENSSL_INCLUDE=... OPENSSL_LIB=... cpanm Crypt::SSLeay

or, on Windows,

> set OPENSSL_INCLUDE=...
> set OPENSSL_LIB=...
> cpanm Crypt::SSLeay

If you are on Windows, and using a MinGW distribution bundled with ActiveState Perl or Strawberry Perl, you would use dmake rather than make. If you are using Microsoft's build tools, you would use nmake.

For unattended (batch) installations, to be absolutely certain that Makefile.PL does not prompt for questions on STDIN, set the environment variable PERL_MM_USE_DEFAULT=1 as with any CPAN module built using ExtUtils::MakeMaker.

VMS

I do not have any experience with VMS. If OpenSSL headers and libraries are not in standard locations searched by your build system by default, please set things up so that they are. If you have generic instructions on how to do it, please open a ticket on RT with the information so I can add it to this document.

Proxy Support

LWP::UserAgent and Crypt::SSLeay have their own versions of proxy support. Please read these sections to see which one is appropriate.

LWP::UserAgent proxy support

LWP::UserAgent has its own methods of proxying which may work for you and is likely to be incompatible with Crypt::SSLeay proxy support. To use LWP::UserAgent proxy support, try something like:

my $ua = LWP::UserAgent->new;
$ua->proxy([qw( https http )], "$proxy_ip:$proxy_port");

At the time of this writing, libwww v5.6 seems to proxy https requests fine with an Apache mod_proxy server. It sends a line like:

GET https://www.example.com HTTP/1.1

to the proxy server, which is not the CONNECT request that some proxies would expect, so this may not work with other proxy servers than mod_proxy. The CONNECT method is used by Crypt::SSLeay's internal proxy support.

Crypt::SSLeay proxy support

For native Crypt::SSLeay proxy support of https requests, you need to set the environment variable HTTPS_PROXY to your proxy server and port, as in:

# proxy support
$ENV{HTTPS_PROXY} = 'http://proxy_hostname_or_ip:port';
$ENV{HTTPS_PROXY} = '127.0.0.1:8080';

Use of the HTTPS_PROXY environment variable in this way is similar to LWP::UserAgent->env_proxy() usage, but calling that method will likely override or break the Crypt::SSLeay support, so do not mix the two.

Basic authentication credentials to the proxy server can be provided this way:

# proxy_basic_auth
$ENV{HTTPS_PROXY_USERNAME} = 'username';
$ENV{HTTPS_PROXY_PASSWORD} = 'password';

For an example of LWP scripting with Crypt::SSLeay native proxy support, please look at the eg/lwp-ssl-test script in the Crypt::SSLeay distribution.

Client Certificate Support

Client certificates are supported. PEM encoded certificate and private key files may be used like this:

$ENV{HTTPS_CERT_FILE} = 'certs/notacacert.pem';
$ENV{HTTPS_KEY_FILE}  = 'certs/notacakeynopass.pem';

You may test your files with the eg/net-ssl-test program, bundled with the distribution, by issuing a command like:

perl eg/net-ssl-test -cert=certs/notacacert.pem \
    -key=certs/notacakeynopass.pem -d GET $HOST_NAME

Additionally, if you would like to tell the client where the CA file is, you may set these.

    $ENV{HTTPS_CA_FILE} = "some_file";
    $ENV{HTTPS_CA_DIR}  = "some_dir";

Note that, if specified, $ENV{HTTPS_CA_FILE} must point to the actual certificate file. That is, $ENV{HTTPS_CA_DIR} is not the path where $ENV{HTTPS_CA_FILE} is located.

For certificates in $ENV{HTTPS_CA_DIR} to be picked up, follow the instructions on http://www.openssl.org/docs/ssl/SSL_CTX_load_verify_locations.html.

There is no sample CA cert file at this time for testing, but you may configure eg/net-ssl-test to use your CA cert with the -CAfile option. (TODO: then what is the ./certs directory in the distribution?)

Creating a test certificate

To create simple test certificates with OpenSSL, you may run the following command:

openssl req -config /usr/local/openssl/openssl.cnf \
    -new -days 365 -newkey rsa:1024 -x509 \
    -keyout notacakey.pem -out notacacert.pem

To remove the pass phrase from the key file, run:

openssl rsa -in notacakey.pem -out notacakeynopass.pem

PKCS12 support

The directives for enabling use of PKCS12 certificates is:

$ENV{HTTPS_PKCS12_FILE}     = 'certs/pkcs12.pkcs12';
$ENV{HTTPS_PKCS12_PASSWORD} = 'PKCS12_PASSWORD';

Use of this type of certificate takes precedence over previous certificate settings described. (TODO: unclear? Meaning "the presence of this type of certificate"?)

SSL versions

Crypt::SSLeay tries very hard to connect to any SSL web server accomodating servers that are buggy, old or simply not standards-compliant. To this effect, this module will try SSL connections in this order:

  • SSL v23 : should allow v2 and v3 servers to pick their best type

  • SSL v3 : best connection type

  • SSL v2 : old connection type

Unfortunately, some servers seem not to handle a reconnect to SSL v3 after a failed connect of SSL v23 is tried, so you may set before using LWP or Net::SSL:

$ENV{HTTPS_VERSION} = 3;

to force a version 3 SSL connection first. At this time, only a version 2 SSL connection will be tried after this, as the connection attempt order remains unchanged by this setting.

Acknowledgements

many thanks to the following individuals who helped improve Crypt-SSLeay:

  • Gisle Aas for writing this module and many others including libwww, for Perl. The web will never be the same :)

  • Ben Laurie deserves kudos for his excellent patches for better error handling, SSL information inspection, and random seeding.

  • Dongqiang Bai for host name resolution fix when using a proxy.

  • Stuart Horner of Core Communications, Inc. who found the need for building --shared OpenSSL libraries.

  • Pavel Hlavnicka for a patch for freeing memory when using a pkcs12 file, and for inspiring more robust read() behavior.

  • James Woodyatt is a champ for finding a ridiculous memory leak that has been the bane of many a Crypt::SSLeay user.

  • Bryan Hart for his patch adding proxy support, and thanks to Tobias Manthey for submitting another approach.

  • Alex Rhomberg for Alpha linux ccc patch.

  • Tobias Manthey for his patches for client certificate support.

  • Daisuke Kuroda for adding PKCS12 certificate support.

  • Gamid Isayev for CA cert support and insights into error messaging.

  • Jeff Long for working through a tricky CA cert SSLClientVerify issue.

  • Chip Turner for a patch to build under perl 5.8.0.

  • Joshua Chamas for the time he spent maintaining the module.

  • Jeff Lavallee for help with alarms on read failures (CPAN bug #12444).

  • Guenter Knauf for significant improvements in configuring things in Win32 and Netware lands and Jan Dubois for various suggestions for improvements.

and many others who provided bug reports, suggestions, fixes and patches.

If you have reported a bug or provided feedback, and you would like to be mentioned by name in this section, please file request on rt.cpan.org.

TODO: Update acknowledgements list.

See Also

Support

Authors

This module was originally written by Gisle Aas, and was subsequently maintained by Joshua Chamas, David Landgren, brian d foy, and A. Sinan Unur.

Copyright

Copyright © 2010-2014 A. Sinan Unur

Copyright © 2006-2007 David Landgren

Copyright © 1999-2003 Joshua Chamas

Copyright © 1998 Gisle Aas

License

This program is free software; you can redistribute it and/or modify it under the terms of Artistic License 2.0.

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