NAME

Net::SSLeay - Perl bindings for OpenSSL and LibreSSL

SYNOPSIS

use Net::SSLeay qw(get_https post_https sslcat make_headers make_form); ($page) = get_https(www.bacus.pt, 443, /); # Case 1 ($page, $response, %reply_headers) = get_https(www.bacus.pt, 443, /, # Case 2 make_headers(User-Agent => Cryptozilla/5.0b1, Referer => https://www.bacus.pt )); ($page, $result, %headers) = # Case 2b = get_https(www.bacus.pt, 443, /protected.html, make_headers(Authorization => Basic . MIME::Base64::encode("$user:$pass",)) ); ($page, $response, %reply_headers) = post_https(www.bacus.pt, 443, /foo.cgi, , # Case 3 make_form(OK => 1, name => Sampo )); $reply = sslcat($host, $port, $request); # Case 4 ($reply, $err, $server_cert) = sslcat($host, $port, $request); # Case 5 $Net::SSLeay::trace = 2; # 0=no debugging, 1=ciphers, 2=trace, 3=dump data Net::SSLeay::initialize(); # Initialize ssl library once

DESCRIPTION

This module provides Perl bindings for libssl (an SSL/TLS API) and libcrypto (a cryptography API).

COMPATIBILITY

Net::SSLeay supports the following libssl implementations:

Net::SSLeay may not function as expected with releases other than the ones listed above due to libssl API incompatibilities, or, in the case of LibreSSL, because of deviations from the libssl API.

Net::SSLeay is only as secure as the underlying libssl implementation you use. Although Net::SSLeay maintains compatibility with old versions of OpenSSL and LibreSSL, it is strongly recommended that you use a version of OpenSSL or LibreSSL that is supported by the OpenSSL/LibreSSL developers and/or your operating system vendor. Many unsupported versions of OpenSSL and LibreSSL are known to contain severe security vulnerabilities. Refer to the OpenSSL Release Strategy <https://www.openssl.org/policies/releasestrat.html> and LibreSSL Support Schedule <https://www.libressl.org/releases.html> for information on which versions are currently supported.

The libssl API has changed significantly since OpenSSL 0.9.8: hundreds of functions have been added, deprecated or removed in the intervening versions. Although this documentation lists all of the functions and constants that Net::SSLeay may expose, they will not be available for use if they are missing from the underlying libssl implementation. Refer to the compatibility notes in this documentation, as well as the OpenSSL/LibreSSL manual pages, for information on which OpenSSL/LibreSSL versions support each function or constant. At run-time, you can check whether a function or constant is exposed before calling it using the following convention:

if ( defined &Net::SSLeay::libssl_function ) { # libssl_function() (or SSL_libssl_function()) is available Net::SSLeay::libssl_function(...); }

OVERVIEW

Net::SSLeay module basically comprise of:

There is also a related module called Net::SSLeay::Handle included in this distribution that you might want to use instead. It has its own pod documentation.

High level functions for accessing web servers

This module offers some high level convenience functions for accessing web pages on SSL servers (for symmetry, the same API is offered for accessing http servers, too), an sslcat() function for writing your own clients, and finally access to the SSL api of the SSLeay/OpenSSL package so you can write servers or clients for more complicated applications.

For high level functions it is most convenient to import them into your main namespace as indicated in the synopsis.

Basic set of functions

Case 1 (in SYNOPSIS) demonstrates the typical invocation of get_https() to fetch an HTML page from secure server. The first argument provides the hostname or IP in dotted decimal notation of the remote server to contact. The second argument is the TCP port at the remote end (your own port is picked arbitrarily from high numbered ports as usual for TCP). The third argument is the URL of the page without the host name part. If in doubt consult the HTTP specifications at <http://www.w3c.org>.

Case 2 (in SYNOPSIS) demonstrates full fledged use of get_https(). As can be seen, get_https() parses the response and response headers and returns them as a list, which can be captured in a hash for later reference. Also a fourth argument to get_https() is used to insert some additional headers in the request. make_headers() is a function that will convert a list or hash to such headers. By default get_https() supplies Host (to make virtual hosting easy) and Accept (reportedly needed by IIS) headers.

Case 2b (in SYNOPSIS) demonstrates how to get a password protected page. Refer to the HTTP protocol specifications for further details (e.g. RFC-2617).

Case 3 (in SYNOPSIS) invokes post_https() to submit a HTML/CGI form to a secure server. The first four arguments are equal to get_https() (note that the empty string () is passed as header argument). The fifth argument is the contents of the form formatted according to CGI specification. Do not post UTF-8 data as content: use utf8::downgrade first. In this case the helper function make_https() is used to do the formatting, but you could pass any string. post_https() automatically adds Content-Type and Content-Length headers to the request.

Case 4 (in SYNOPSIS) shows the fundamental sslcat() function (inspired in spirit by the netcat utility :-). It's your swiss army knife that allows you to easily contact servers, send some data, and then get the response. You are responsible for formatting the data and parsing the response - sslcat() is just a transport.

Case 5 (in SYNOPSIS) is a full invocation of sslcat() which allows the return of errors as well as the server (peer) certificate.

The $trace global variable can be used to control the verbosity of the high level functions. Level 0 guarantees silence, level 1 (the default) only emits error messages.

Alternate versions of high-level API

The above mentioned functions actually return the response headers as a list, which only gets converted to hash upon assignment (this assignment looses information if the same header occurs twice, as may be the case with cookies). There are also other variants of the functions that return unprocessed headers and that return a reference to a hash.

($page, $response, @headers) = get_https(www.bacus.pt, 443, /); for ($i = 0; $i < $#headers; $i+=2) { print "$headers[$i] = " . $headers[$i+1] . "\n"; } ($page, $response, $headers, $server_cert) = get_https3(www.bacus.pt, 443, /); print "$headers\n"; ($page, $response, $headers_ref) = get_https4(www.bacus.pt, 443, /); for $k (sort keys %{$headers_ref}) { for $v (@{$$headers_ref{$k}}) { print "$k = $v\n"; } }

All of the above code fragments accomplish the same thing: display all values of all headers. The API functions ending in 3 return the headers simply as a scalar string and it is up to the application to split them up. The functions ending in 4 return a reference to a hash of arrays (see perlref and perllol if you are not familiar with complex perl data structures). To access a single value of such a header hash you would do something like

print $$headers_ref{COOKIE}[0];

Variants 3 and 4 also allow you to discover the server certificate in case you would like to store or display it, e.g.

($p, $resp, $hdrs, $server_cert) = get_https3(www.bacus.pt, 443, /); if (!defined($server_cert) || ($server_cert == 0)) { warn "Subject Name: undefined, Issuer Name: undefined"; } else { warn Subject Name: . Net::SSLeay::X509_NAME_oneline( Net::SSLeay::X509_get_subject_name($server_cert)) . Issuer Name: . Net::SSLeay::X509_NAME_oneline( Net::SSLeay::X509_get_issuer_name($server_cert)); }

Beware that this method only allows after the fact verification of the certificate: by the time get_https3() has returned the https request has already been sent to the server, whether you decide to trust it or not. To do the verification correctly you must either employ the OpenSSL certificate verification framework or use the lower level API to first connect and verify the certificate and only then send the http data. See the implementation of ds_https3() for guidance on how to do this.

Using client certificates

Secure web communications are encrypted using symmetric crypto keys exchanged using encryption based on the certificate of the server. Therefore in all SSL connections the server must have a certificate. This serves both to authenticate the server to the clients and to perform the key exchange.

Sometimes it is necessary to authenticate the client as well. Two options are available: HTTP basic authentication and a client side certificate. The basic authentication over HTTPS is actually quite safe because HTTPS guarantees that the password will not travel in the clear. Never-the-less, problems like easily guessable passwords remain. The client certificate method involves authentication of the client at the SSL level using a certificate. For this to work, both the client and the server have certificates (which typically are different) and private keys.

The API functions outlined above accept additional arguments that allow one to supply the client side certificate and key files. The format of these files is the same as used for server certificates and the caveat about encrypting private keys applies.

($page, $result, %headers) = # 2c = get_https(www.bacus.pt, 443, /protected.html, make_headers(Authorization => Basic . MIME::Base64::encode("$user:$pass",)), , $mime_type6, $path_to_crt7, $path_to_key8); ($page, $response, %reply_headers) = post_https(www.bacus.pt, 443, /foo.cgi, # 3b make_headers(Authorization => Basic . MIME::Base64::encode("$user:$pass",)), make_form(OK => 1, name => Sampo), $mime_type6, $path_to_crt7, $path_to_key8);

Case 2c (in SYNOPSIS) demonstrates getting a password protected page that also requires a client certificate, i.e. it is possible to use both authentication methods simultaneously.

Case 3b (in SYNOPSIS) is a full blown POST to a secure server that requires both password authentication and a client certificate, just like in case 2c.

Note: The client will not send a certificate unless the server requests one. This is typically achieved by setting the verify mode to VERIFY_PEER on the server:

Net::SSLeay::set_verify(ssl, Net::SSLeay::VERIFY_PEER, 0);

See perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod for a full description.

Working through a web proxy

Net::SSLeay can use a web proxy to make its connections. You need to first set the proxy host and port using set_proxy() and then just use the normal API functions, e.g:

Net::SSLeay::set_proxy(gateway.myorg.com, 8080); ($page) = get_https(www.bacus.pt, 443, /);

If your proxy requires authentication, you can supply a username and password as well

Net::SSLeay::set_proxy(gateway.myorg.com, 8080, joe, salainen); ($page, $result, %headers) = = get_https(www.bacus.pt, 443, /protected.html, make_headers(Authorization => Basic . MIME::Base64::encode("susie:pass",)) );

This example demonstrates the case where we authenticate to the proxy as "joe" and to the final web server as "susie". Proxy authentication requires the MIME::Base64 module to work.

HTTP (without S) API

Over the years it has become clear that it would be convenient to use the light-weight flavour API of Net::SSLeay for normal HTTP as well (see LWP for the heavy-weight object-oriented approach). In fact it would be nice to be able to flip https on and off on the fly. Thus regular HTTP support was evolved.

use Net::SSLeay qw(get_http post_http tcpcat get_httpx post_httpx tcpxcat make_headers make_form); ($page, $result, %headers) = get_http(www.bacus.pt, 443, /protected.html, make_headers(Authorization => Basic . MIME::Base64::encode("$user:$pass",)) ); ($page, $response, %reply_headers) = post_http(www.bacus.pt, 443, /foo.cgi, , make_form(OK => 1, name => Sampo )); ($reply, $err) = tcpcat($host, $port, $request); ($page, $result, %headers) = get_httpx($usessl, www.bacus.pt, 443, /protected.html, make_headers(Authorization => Basic . MIME::Base64::encode("$user:$pass",)) ); ($page, $response, %reply_headers) = post_httpx($usessl, www.bacus.pt, 443, /foo.cgi, , make_form(OK => 1, name => Sampo )); ($reply, $err, $server_cert) = tcpxcat($usessl, $host, $port, $request);

As can be seen, the "x" family of APIs takes as the first argument a flag which indicates whether SSL is used or not.

Certificate verification and Certificate Revocation Lists (CRLs)

OpenSSL supports the ability to verify peer certificates. It can also optionally check the peer certificate against a Certificate Revocation List (CRL) from the certificates issuer. A CRL is a file, created by the certificate issuer that lists all the certificates that it previously signed, but which it now revokes. CRLs are in PEM format.

You can enable Net::SSLeay CRL checking like this:

&Net::SSLeay::X509_STORE_set_flags (&Net::SSLeay::CTX_get_cert_store($ssl), &Net::SSLeay::X509_V_FLAG_CRL_CHECK);

After setting this flag, if OpenSSL checks a peer's certificate, then it will attempt to find a CRL for the issuer. It does this by looking for a specially named file in the search directory specified by CTX_load_verify_locations. CRL files are named with the hash of the issuer's subject name, followed by .r0, .r1 etc. For example ab1331b2.r0, ab1331b2.r1. It will read all the .r files for the issuer, and then check for a revocation of the peer certificate in all of them. (You can also force it to look in a specific named CRL file., see below). You can find out the hash of the issuer subject name in a CRL with

openssl crl -in crl.pem -hash -noout

If the peer certificate does not pass the revocation list, or if no CRL is found, then the handshaking fails with an error.

You can also force OpenSSL to look for CRLs in one or more arbitrarily named files.

my $bio = Net::SSLeay::BIO_new_file($crlfilename, r); my $crl = Net::SSLeay::PEM_read_bio_X509_CRL($bio); if ($crl) { Net::SSLeay::X509_STORE_add_crl( Net::SSLeay::CTX_get_cert_store($ssl, $crl) ); } else { error reading CRL.... }

Usually the URLs where you can download the CRLs is contained in the certificate itself and you can extract them with

my @url = Net::SSLeay::P_X509_get_crl_distribution_points($cert)

But there is no automatic downloading of the CRLs and often these CRLs are too huge to just download them to verify a single certificate. Also, these CRLs are often in DER format which you need to convert to PEM before you can use it:

openssl crl -in crl.der -inform der -out crl.pem

So as an alternative for faster and timely revocation checks you better use the Online Status Revocation Protocol (OCSP).

Certificate verification and Online Status Revocation Protocol (OCSP)

While checking for revoked certificates is possible and fast with Certificate Revocation Lists, you need to download the complete and often huge list before you can verify a single certificate.

A faster way is to ask the CA to check the revocation of just a single or a few certificates using OCSP. Basically you generate for each certificate an OCSP_CERTID based on the certificate itself and its issuer, put the ids togetether into an OCSP_REQUEST and send the request to the URL given in the certificate.

As a result you get back an OCSP_RESPONSE and need to check the status of the response, check that it is valid (e.g. signed by the CA) and finally extract the information about each OCSP_CERTID to find out if the certificate is still valid or got revoked.

With Net::SSLeay this can be done like this:

# get id(s) for given certs, like from get_peer_certificate # or get_peer_cert_chain. This will croak if # - one tries to make an OCSP_CERTID for a self-signed certificate # - the issuer of the certificate cannot be found in the SSL objects # store, nor in the current certificate chain my $cert = Net::SSLeay::get_peer_certificate($ssl); my $id = eval { Net::SSLeay::OCSP_cert2ids($ssl,$cert) }; die "failed to make OCSP_CERTID: $@" if $@; # create OCSP_REQUEST from id(s) # Multiple can be put into the same request, if the same OCSP responder # is responsible for them. my $req = Net::SSLeay::OCSP_ids2req($id); # determine URI of OCSP responder my $uri = Net::SSLeay::P_X509_get_ocsp_uri($cert); # Send stringified OCSP_REQUEST with POST to $uri. # We can ignore certificate verification for https, because the OCSP # response itself is signed. my $ua = HTTP::Tiny->new(verify_SSL => 0); my $res = $ua->request( POST,$uri, { headers => { Content-type => application/ocsp-request }, content => Net::SSLeay::i2d_OCSP_REQUEST($req) }); my $content = $res && $res->{success} && $res->{content} or die "query failed"; # Extract OCSP_RESPONSE. # this will croak if the string is not an OCSP_RESPONSE my $resp = eval { Net::SSLeay::d2i_OCSP_RESPONSE($content) }; # Check status of response. my $status = Net::SSLeay::OCSP_response_status($resp); if ($status != Net::SSLeay::OCSP_RESPONSE_STATUS_SUCCESSFUL()) die "OCSP response failed: ". Net::SSLeay::OCSP_response_status_str($status); } # Verify signature of response and if nonce matches request. # This will croak if there is a nonce in the response, but it does not match # the request. It will return false if the signature could not be verified, # in which case details can be retrieved with Net::SSLeay::ERR_get_error. # It will not complain if the response does not contain a nonce, which is # usually the case with pre-signed responses. if ( ! eval { Net::SSLeay::OCSP_response_verify($ssl,$resp,$req) }) { die "OCSP response verification failed"; } # Extract information from OCSP_RESPONSE for each of the ids. # If called in scalar context it will return the time (as time_t), when the # next update is due (minimum of all successful responses inside $resp). It # will croak on the following problems: # - response is expired or not yet valid # - no response for given OCSP_CERTID # - certificate status is not good (e.g. revoked or unknown) if ( my $nextupd = eval { Net::SSLeay::OCSP_response_results($resp,$id) }) { warn "certificate is valid, next update in ". ($nextupd-time())." seconds\n"; } else { die "certificate is not valid: $@"; } # But in array context it will return detailed information about each given # OCSP_CERTID instead croaking on errors: # if no @ids are given it will return information about all single responses # in the OCSP_RESPONSE my @results = Net::SSLeay::OCSP_response_results($resp,@ids); for my $r (@results) { print Dumper($r); # @results are in the same order as the @ids and contain: # $r->[0] - OCSP_CERTID # $r->[1] - undef if no error (certificate good) OR error message as string # $r->[2] - hash with details: # thisUpdate - time_t of this single response # nextUpdate - time_t when update is expected # statusType - integer: # V_OCSP_CERTSTATUS_GOOD(0) # V_OCSP_CERTSTATUS_REVOKED(1) # V_OCSP_CERTSTATUS_UNKNOWN(2) # revocationTime - time_t (only if revoked) # revocationReason - integer (only if revoked) # revocationReason_str - reason as string (only if revoked) }

To further speed up certificate revocation checking one can use a TLS extension to instruct the server to staple the OCSP response:

# set TLS extension before doing SSL_connect Net::SSLeay::set_tlsext_status_type($ssl, Net::SSLeay::TLSEXT_STATUSTYPE_ocsp()); # setup callback to verify OCSP response my $cert_valid = undef; Net::SSLeay::CTX_set_tlsext_status_cb($context,sub { my ($ssl,$resp) = @_; if (!$resp) { # Lots of servers dont return an OCSP response. # In this case we must check the OCSP status outside the SSL # handshake. warn "server did not return stapled OCSP response\n"; return 1; } # verify status my $status = Net::SSLeay::OCSP_response_status($resp); if ($status != Net::SSLeay::OCSP_RESPONSE_STATUS_SUCCESSFUL()) { warn "OCSP response failure: $status\n"; return 1; } # verify signature - we have no OCSP_REQUEST here to check nonce if (!eval { Net::SSLeay::OCSP_response_verify($ssl,$resp) }) { warn "OCSP response verify failed\n"; return 1; } # check if the certificate is valid # we should check here against the peer_certificate my $cert = Net::SSLeay::get_peer_certificate(); my $certid = eval { Net::SSLeay::OCSP_cert2ids($ssl,$cert) } or do { warn "cannot get certid from cert: $@"; $cert_valid = -1; return 1; }; if ( $nextupd = eval { Net::SSLeay::OCSP_response_results($resp,$certid) }) { warn "certificate not revoked\n"; $cert_valid = 1; } else { warn "certificate not valid: $@"; $cert_valid = 0; } }); # do SSL handshake here .... # check if certificate revocation was checked already if ( ! defined $cert_valid) { # check revocation outside of SSL handshake by asking OCSP responder ... } elsif ( ! $cert_valid ) { die "certificate not valid - closing SSL connection"; } elsif ( $cert_valid<0 ) { die "cannot verify certificate revocation - self-signed ?"; } else { # everything fine ... }

Using Net::SSLeay in multi-threaded applications

IMPORTANT: versions 1.42 or earlier are not thread-safe!

Net::SSLeay module implements all necessary stuff to be ready for multi-threaded environment - it requires openssl-0.9.7 or newer. The implementation fully follows thread safety related requirements of openssl library(see <http://www.openssl.org/docs/crypto/threads.html>).

If you are about to use Net::SSLeay (or any other module based on Net::SSLeay) in multi-threaded perl application it is recommended to follow this best-practice:

Initialization

Load and initialize Net::SSLeay module in the main thread:

use threads; use Net::SSLeay; Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); sub do_master_job { #... call whatever from Net::SSLeay } sub do_worker_job { #... call whatever from Net::SSLeay } #start threads my $master = threads->new(\&do_master_job, param1, param2); my @workers = threads->new(\&do_worker_job, arg1, arg2) for (1..10); #waiting for all threads to finish $_->join() for (threads->list);

NOTE: Openssl's int SSL_library_init(void) function (which is also aliased as SSLeay_add_ssl_algorithms, OpenSSL_add_ssl_algorithms and add_ssl_algorithms) is not re-entrant and multiple calls can cause a crash in threaded application. Net::SSLeay implements flags preventing repeated calls to this function, therefore even multiple initialization via Net::SSLeay::SSLeay_add_ssl_algorithms() should work without trouble.

Using callbacks

Do not use callbacks across threads (the module blocks cross-thread callback operations and throws a warning). Always do the callback setup, callback use and callback destruction within the same thread.

Using openssl elements

All openssl elements (X509, SSL_CTX, ...) can be directly passed between threads.

use threads; use Net::SSLeay; Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); sub do_job { my $context = shift; Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" }); #... } my $c = Net::SSLeay::CTX_new(); threads->create(\&do_job, $c);

Or:

use threads; use Net::SSLeay; my $context; #does not need to be shared Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); sub do_job { Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" }); #... } $context = Net::SSLeay::CTX_new(); threads->create(\&do_job);

Using other perl modules based on Net::SSLeay

It should be fine to use any other module based on Net::SSLeay (like IO::Socket::SSL) in multi-threaded applications. It is generally recommended to do any global initialization of such a module in the main thread before calling threads->new(..) or threads->create(..) but it might differ module by module.

To be safe you can load and init Net::SSLeay explicitly in the main thread:

use Net::SSLeay; use Other::SSLeay::Based::Module; Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize();

Or even safer:

use Net::SSLeay; use Other::SSLeay::Based::Module; BEGIN { Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); }

Combining Net::SSLeay with other modules linked with openssl

BEWARE: This might be a big trouble! This is not guaranteed be thread-safe!

There are many other (XS) modules linked directly to openssl library (like Crypt::SSLeay).

As it is expected that also another module will call SSLeay_add_ssl_algorithms at some point we have again a trouble with multiple openssl initialization by Net::SSLeay and another module.

As you can expect Net::SSLeay is not able to avoid multiple initialization of openssl library called by another module, thus you have to handle this on your own (in some cases it might not be possible at all to avoid this).

Threading with get_https and friends

The convenience functions get_https, post_https etc all initialize the SSL library by calling Net::SSLeay::initialize which does the conventional library initialization:

Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize();

Net::SSLeay::initialize initializes the SSL library at most once. You can override the Net::SSLeay::initialize function if you desire some other type of initialization behaviour by get_https and friends. You can call Net::SSLeay::initialize from your own code if you desire this conventional library initialization.

Convenience routines

To be used with Low level API

Net::SSLeay::randomize($rn_seed_file,$additional_seed); Net::SSLeay::set_cert_and_key($ctx, $cert_path, $key_path); $cert = Net::SSLeay::dump_peer_certificate($ssl); Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write failure"; $got = Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure"; $got = Net::SSLeay::ssl_read_CRLF($ssl [, $max_length]); $got = Net::SSLeay::ssl_read_until($ssl [, $delimit [, $max_length]]); Net::SSLeay::ssl_write_CRLF($ssl, $message);

Initialization

In order to use the low level API you should start your programs with the following incantation:

use Net::SSLeay qw(die_now die_if_ssl_error); Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); # Important! Net::SSLeay::ENGINE_load_builtin_engines(); # If you want built-in engines Net::SSLeay::ENGINE_register_all_complete(); # If you want built-in engines Net::SSLeay::randomize();

Error handling functions

I can not emphasize the need to check for error enough. Use these functions even in the most simple programs, they will reduce debugging time greatly. Do not ask questions on the mailing list without having first sprinkled these in your code.

Sockets

Perl uses file handles for all I/O. While SSLeay has a quite flexible BIO mechanism and perl has an evolved PerlIO mechanism, this module still sticks to using file descriptors. Thus to attach SSLeay to a socket you should use fileno() to extract the underlying file descriptor:

Net::SSLeay::set_fd($ssl, fileno(S)); # Must use fileno

You should also set $| to 1 to eliminate STDIO buffering so you do not get confused if you use perl I/O functions to manipulate your socket handle.

If you need to select(2) on the socket, go right ahead, but be warned that OpenSSL does some internal buffering so SSL_read does not always return data even if the socket selected for reading (just keep on selecting and trying to read). Net::SSLeay is no different from the C language OpenSSL in this respect.

Callbacks

You can establish a per-context verify callback function something like this:

sub verify { my ($ok, $x509_store_ctx) = @_; print "Verifying certificate...\n"; ... return $ok; }

It is used like this:

Net::SSLeay::set_verify ($ssl, Net::SSLeay::VERIFY_PEER, \&verify);

Per-context callbacks for decrypting private keys are implemented.

Net::SSLeay::CTX_set_default_passwd_cb($ctx, sub { "top-secret" }); Net::SSLeay::CTX_use_PrivateKey_file($ctx, "key.pem", Net::SSLeay::FILETYPE_PEM) or die "Error reading private key"; Net::SSLeay::CTX_set_default_passwd_cb($ctx, undef);

If Hello Extensions are supported by your OpenSSL, a session secret callback can be set up to be called when a session secret is set by openssl.

Establish it like this:

Net::SSLeay::set_session_secret_cb($ssl, \&session_secret_cb, $somedata);

It will be called like this:

sub session_secret_cb { my ($secret, \@cipherlist, \$preferredcipher, $somedata) = @_; }

No other callbacks are implemented. You do not need to use any callback for simple (i.e. normal) cases where the SSLeay built-in verify mechanism satisfies your needs.

It is required to reset these callbacks to undef immediately after use to prevent memory leaks, thread safety problems and crashes on exit that can occur if different threads set different callbacks.

If you want to use callback stuff, see examples/callback.pl! It's the only one I am able to make work reliably.

Low level API

In addition to the high level functions outlined above, this module contains straight-forward access to CRYPTO and SSL parts of OpenSSL C API.

See the *.h headers from OpenSSL C distribution for a list of low level SSLeay functions to call (check SSLeay.xs to see if some function has been implemented). The module strips the initial "SSL_" off of the SSLeay names. Generally you should use Net::SSLeay:: in its place.

Note that some functions are prefixed with "P_" - these are very close to the original API however contain some kind of a wrapper making its interface more perl friendly.

For example:

In C:

#include <ssl.h> err = SSL_set_verify (ssl, SSL_VERIFY_CLIENT_ONCE, &your_call_back_here);

In Perl:

use Net::SSLeay; $err = Net::SSLeay::set_verify ($ssl, Net::SSLeay::VERIFY_CLIENT_ONCE, \&your_call_back_here);

If the function does not start with SSL_ you should use the full function name, e.g.:

$err = Net::SSLeay::ERR_get_error;

The following new functions behave in perlish way:

$got = Net::SSLeay::read($ssl); # Performs SSL_read, but returns $got # resized according to data received. # Returns undef on failure. Net::SSLeay::write($ssl, $foo) || die; # Performs SSL_write, but automatically # figures out the size of $foo

Low level API: Version and library information related functions

Low level API: Initialization related functions

Low level API: ERR_* and SSL_alert_* related functions

NOTE: Please note that SSL_alert_* function have SSL_ part stripped from their names.

Low level API: SSL_METHOD_* related functions

Low level API: ENGINE_* related functions

Low level API: EVP_PKEY_* related functions

Low level API: PEM_* related functions

Check openssl doc <http://www.openssl.org/docs/crypto/pem.html>

Low level API: d2i_* (DER format) related functions

Low level API: PKCS12 related functions

Low level API: SESSION_* related functions

Low level API: SSL_CTX_* related functions

NOTE: Please note that the function described in this chapter have SSL_ part stripped from their original openssl names.

Low level API: SSL_* related functions

NOTE: Please note that the function described in this chapter have SSL_ part stripped from their original openssl names.

Low level API: RAND_* related functions

Check openssl doc related to RAND stuff <http://www.openssl.org/docs/crypto/rand.html>

Low level API: OBJ_* related functions

Low level API: ASN1_INTEGER_* related functions

Low level API: ASN1_STRING_* related functions

Low level API: ASN1_TIME_* related functions

Low level API: X509_* related functions

Low level API: X509_REQ_* related functions

Low level API: X509_CRL_* related functions

Low level API: X509_EXTENSION_* related functions

Low level API: X509_NAME_* related functions

Low level API: X509_STORE_* related functions

Low Level API: X509_INFO related functions

Low level API: X509_VERIFY_PARAM_* related functions

Low level API: Cipher (EVP_CIPHER_*) related functions

Low level API: Digest (EVP_MD_*) related functions

Low level API: CIPHER_* related functions

Low level API: RSA_* related functions

Low level API: BIO_* related functions

Low level API: Server side Server Name Indication (SNI) support

Low level API: NPN (next protocol negotiation) related functions

NPN is being replaced with ALPN, a more recent TLS extension for application protocol negotiation that's in process of being adopted by IETF. Please look below for APLN API description.

Simple approach for using NPN support looks like this:

### client side use Net::SSLeay; use IO::Socket::INET; Net::SSLeay::initialize(); my $sock = IO::Socket::INET->new(PeerAddr=>encrypted.google.com:443) or die; my $ctx = Net::SSLeay::CTX_tlsv1_new() or die; Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL); Net::SSLeay::CTX_set_next_proto_select_cb($ctx, [http1.1,spdy/2]); my $ssl = Net::SSLeay::new($ctx) or die; Net::SSLeay::set_fd($ssl, fileno($sock)) or die; Net::SSLeay::connect($ssl); warn "client:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl), "\n"; warn "client:last_status=", Net::SSLeay::P_next_proto_last_status($ssl), "\n"; ### server side use Net::SSLeay; use IO::Socket::INET; Net::SSLeay::initialize(); my $ctx = Net::SSLeay::CTX_tlsv1_new() or die; Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL); Net::SSLeay::set_cert_and_key($ctx, "cert.pem", "key.pem"); Net::SSLeay::CTX_set_next_protos_advertised_cb($ctx, [spdy/2,http1.1]); my $sock = IO::Socket::INET->new(LocalAddr=>localhost, LocalPort=>5443, Proto=>tcp, Listen=>20) or die; while (1) { my $ssl = Net::SSLeay::new($ctx); warn("server:waiting for incoming connection...\n"); my $fd = $sock->accept(); Net::SSLeay::set_fd($ssl, $fd->fileno); Net::SSLeay::accept($ssl); warn "server:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl),"\n"; my $got = Net::SSLeay::read($ssl); Net::SSLeay::ssl_write_all($ssl, "length=".length($got)); Net::SSLeay::free($ssl); $fd->close(); } # check with: openssl s_client -connect localhost:5443 -nextprotoneg http/1.1,spdy/2

Please note that the selection (negotiation) is performed by client side, the server side simply advertise the list of supported protocols.

Advanced approach allows you to implement your own negotiation algorithm.

#see below documentation for: Net::SSleay::CTX_set_next_proto_select_cb($ctx, $perl_callback_function, $callback_data); Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $perl_callback_function, $callback_data);

Detection of NPN support (works even in older Net::SSLeay versions):

use Net::SSLeay; if (exists &Net::SSLeay::P_next_proto_negotiated) { # do NPN stuff }

Low level API: ALPN (application layer protocol negotiation) related functions

Application protocol can be negotiated via two different mechanisms employing two different TLS extensions: NPN (obsolete) and ALPN (recommended).

The API is rather similar, with slight differences reflecting protocol specifics. In particular, with ALPN the protocol negotiation takes place on server, while with NPN the client implements the protocol negotiation logic.

With ALPN, the most basic implementation looks like this:

### client side use Net::SSLeay; use IO::Socket::INET; Net::SSLeay::initialize(); my $sock = IO::Socket::INET->new(PeerAddr=>encrypted.google.com:443) or die; my $ctx = Net::SSLeay::CTX_tlsv1_new() or die; Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL); Net::SSLeay::CTX_set_alpn_protos($ctx, [http/1.1, http/2.0, spdy/3]); my $ssl = Net::SSLeay::new($ctx) or die; Net::SSLeay::set_fd($ssl, fileno($sock)) or die; Net::SSLeay::connect($ssl); warn "client:selected=",Net::SSLeay::P_alpn_selected($ssl), "\n"; ### server side use Net::SSLeay; use IO::Socket::INET; Net::SSLeay::initialize(); my $ctx = Net::SSLeay::CTX_tlsv1_new() or die; Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL); Net::SSLeay::set_cert_and_key($ctx, "cert.pem", "key.pem"); Net::SSLeay::CTX_set_alpn_select_cb($ctx, [http/1.1, http/2.0, spdy/3]); my $sock = IO::Socket::INET->new(LocalAddr=>localhost, LocalPort=>5443, Proto=>tcp, Listen=>20) or die; while (1) { my $ssl = Net::SSLeay::new($ctx); warn("server:waiting for incoming connection...\n"); my $fd = $sock->accept(); Net::SSLeay::set_fd($ssl, $fd->fileno); Net::SSLeay::accept($ssl); warn "server:selected=",Net::SSLeay::P_alpn_selected($ssl),"\n"; my $got = Net::SSLeay::read($ssl); Net::SSLeay::ssl_write_all($ssl, "length=".length($got)); Net::SSLeay::free($ssl); $fd->close(); } # check with: openssl s_client -connect localhost:5443 -alpn spdy/3,http/1.1

Advanced approach allows you to implement your own negotiation algorithm.

#see below documentation for: Net::SSleay::CTX_set_alpn_select_cb($ctx, $perl_callback_function, $callback_data);

Detection of ALPN support (works even in older Net::SSLeay versions):

use Net::SSLeay; if (exists &Net::SSLeay::P_alpn_selected) { # do ALPN stuff }

Low level API: DANE Support

OpenSSL version 1.0.2 adds preliminary support RFC6698 Domain Authentication of Named Entities (DANE) Transport Layer Association within OpenSSL

Low level API: Other functions

Low level API: EC related functions

Low level API: OSSL_LIB_CTX and OSSL_PROVIDER related functions

Constants

There are many openssl constants available in Net::SSLeay. You can use them like this:

use Net::SSLeay; print &Net::SSLeay::NID_commonName; #or print Net::SSLeay::NID_commonName();

Or you can import them and use:

use Net::SSLeay qw/NID_commonName/; print &NID_commonName; #or print NID_commonName(); #or print NID_commonName;

The constants names are derived from openssl constants, however constants starting with SSL_ prefix have name with SSL_ part stripped - e.g. openssl's constant SSL_OP_ALL is available as Net::SSleay::OP_ALL

The list of all available constant names:

ASN1_STRFLGS_ESC_CTRL OPENSSL_VERSION_STRING ASN1_STRFLGS_ESC_MSB OP_ALL ASN1_STRFLGS_ESC_QUOTE OP_ALLOW_NO_DHE_KEX ASN1_STRFLGS_RFC2253 OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION CB_ACCEPT_EXIT OP_CIPHER_SERVER_PREFERENCE CB_ACCEPT_LOOP OP_CISCO_ANYCONNECT CB_ALERT OP_COOKIE_EXCHANGE CB_CONNECT_EXIT OP_CRYPTOPRO_TLSEXT_BUG CB_CONNECT_LOOP OP_DONT_INSERT_EMPTY_FRAGMENTS CB_EXIT OP_ENABLE_MIDDLEBOX_COMPAT CB_HANDSHAKE_DONE OP_EPHEMERAL_RSA CB_HANDSHAKE_START OP_LEGACY_SERVER_CONNECT CB_LOOP OP_MICROSOFT_BIG_SSLV3_BUFFER CB_READ OP_MICROSOFT_SESS_ID_BUG CB_READ_ALERT OP_MSIE_SSLV2_RSA_PADDING CB_WRITE OP_NETSCAPE_CA_DN_BUG CB_WRITE_ALERT OP_NETSCAPE_CHALLENGE_BUG ERROR_NONE OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG ERROR_SSL OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG ERROR_SYSCALL OP_NON_EXPORT_FIRST ERROR_WANT_ACCEPT OP_NO_ANTI_REPLAY ERROR_WANT_CONNECT OP_NO_CLIENT_RENEGOTIATION ERROR_WANT_READ OP_NO_COMPRESSION ERROR_WANT_WRITE OP_NO_ENCRYPT_THEN_MAC ERROR_WANT_X509_LOOKUP OP_NO_QUERY_MTU ERROR_ZERO_RETURN OP_NO_RENEGOTIATION EVP_PKS_DSA OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION EVP_PKS_EC OP_NO_SSL_MASK EVP_PKS_RSA OP_NO_SSLv2 EVP_PKT_ENC OP_NO_SSLv3 EVP_PKT_EXCH OP_NO_TICKET EVP_PKT_EXP OP_NO_TLSv1 EVP_PKT_SIGN OP_NO_TLSv1_1 EVP_PK_DH OP_NO_TLSv1_2 EVP_PK_DSA OP_NO_TLSv1_3 EVP_PK_EC OP_PKCS1_CHECK_1 EVP_PK_RSA OP_PKCS1_CHECK_2 FILETYPE_ASN1 OP_PRIORITIZE_CHACHA FILETYPE_PEM OP_SAFARI_ECDHE_ECDSA_BUG F_CLIENT_CERTIFICATE OP_SINGLE_DH_USE F_CLIENT_HELLO OP_SINGLE_ECDH_USE F_CLIENT_MASTER_KEY OP_SSLEAY_080_CLIENT_DH_BUG F_D2I_SSL_SESSION OP_SSLREF2_REUSE_CERT_TYPE_BUG F_GET_CLIENT_FINISHED OP_TLSEXT_PADDING F_GET_CLIENT_HELLO OP_TLS_BLOCK_PADDING_BUG F_GET_CLIENT_MASTER_KEY OP_TLS_D5_BUG F_GET_SERVER_FINISHED OP_TLS_ROLLBACK_BUG F_GET_SERVER_HELLO READING F_GET_SERVER_VERIFY RECEIVED_SHUTDOWN F_I2D_SSL_SESSION RSA_3 F_READ_N RSA_F4 F_REQUEST_CERTIFICATE R_BAD_AUTHENTICATION_TYPE F_SERVER_HELLO R_BAD_CHECKSUM F_SSL_CERT_NEW R_BAD_MAC_DECODE F_SSL_GET_NEW_SESSION R_BAD_RESPONSE_ARGUMENT F_SSL_NEW R_BAD_SSL_FILETYPE F_SSL_READ R_BAD_SSL_SESSION_ID_LENGTH F_SSL_RSA_PRIVATE_DECRYPT R_BAD_STATE F_SSL_RSA_PUBLIC_ENCRYPT R_BAD_WRITE_RETRY F_SSL_SESSION_NEW R_CHALLENGE_IS_DIFFERENT F_SSL_SESSION_PRINT_FP R_CIPHER_TABLE_SRC_ERROR F_SSL_SET_FD R_INVALID_CHALLENGE_LENGTH F_SSL_SET_RFD R_NO_CERTIFICATE_SET F_SSL_SET_WFD R_NO_CERTIFICATE_SPECIFIED F_SSL_USE_CERTIFICATE R_NO_CIPHER_LIST F_SSL_USE_CERTIFICATE_ASN1 R_NO_CIPHER_MATCH F_SSL_USE_CERTIFICATE_FILE R_NO_PRIVATEKEY F_SSL_USE_PRIVATEKEY R_NO_PUBLICKEY F_SSL_USE_PRIVATEKEY_ASN1 R_NULL_SSL_CTX F_SSL_USE_PRIVATEKEY_FILE R_PEER_DID_NOT_RETURN_A_CERTIFICATE F_SSL_USE_RSAPRIVATEKEY R_PEER_ERROR F_SSL_USE_RSAPRIVATEKEY_ASN1 R_PEER_ERROR_CERTIFICATE F_SSL_USE_RSAPRIVATEKEY_FILE R_PEER_ERROR_NO_CIPHER F_WRITE_PENDING R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE GEN_DIRNAME R_PUBLIC_KEY_ENCRYPT_ERROR GEN_DNS R_PUBLIC_KEY_IS_NOT_RSA GEN_EDIPARTY R_READ_WRONG_PACKET_TYPE GEN_EMAIL R_SHORT_READ GEN_IPADD R_SSL_SESSION_ID_IS_DIFFERENT GEN_OTHERNAME R_UNABLE_TO_EXTRACT_PUBLIC_KEY GEN_RID R_UNKNOWN_REMOTE_ERROR_TYPE GEN_URI R_UNKNOWN_STATE GEN_X400 R_X509_LIB LIBRESSL_VERSION_NUMBER SENT_SHUTDOWN MBSTRING_ASC SESSION_ASN1_VERSION MBSTRING_BMP SESS_CACHE_BOTH MBSTRING_FLAG SESS_CACHE_CLIENT MBSTRING_UNIV SESS_CACHE_NO_AUTO_CLEAR MBSTRING_UTF8 SESS_CACHE_NO_INTERNAL MIN_RSA_MODULUS_LENGTH_IN_BYTES SESS_CACHE_NO_INTERNAL_LOOKUP MODE_ACCEPT_MOVING_WRITE_BUFFER SESS_CACHE_NO_INTERNAL_STORE MODE_AUTO_RETRY SESS_CACHE_OFF MODE_ENABLE_PARTIAL_WRITE SESS_CACHE_SERVER MODE_RELEASE_BUFFERS SSL2_MT_CLIENT_CERTIFICATE NID_OCSP_sign SSL2_MT_CLIENT_FINISHED NID_SMIMECapabilities SSL2_MT_CLIENT_HELLO NID_X500 SSL2_MT_CLIENT_MASTER_KEY NID_X509 SSL2_MT_ERROR NID_ad_OCSP SSL2_MT_REQUEST_CERTIFICATE NID_ad_ca_issuers SSL2_MT_SERVER_FINISHED NID_algorithm SSL2_MT_SERVER_HELLO NID_authority_key_identifier SSL2_MT_SERVER_VERIFY NID_basic_constraints SSL2_VERSION NID_bf_cbc SSL3_MT_CCS NID_bf_cfb64 SSL3_MT_CERTIFICATE NID_bf_ecb SSL3_MT_CERTIFICATE_REQUEST NID_bf_ofb64 SSL3_MT_CERTIFICATE_STATUS NID_cast5_cbc SSL3_MT_CERTIFICATE_URL NID_cast5_cfb64 SSL3_MT_CERTIFICATE_VERIFY NID_cast5_ecb SSL3_MT_CHANGE_CIPHER_SPEC NID_cast5_ofb64 SSL3_MT_CLIENT_HELLO NID_certBag SSL3_MT_CLIENT_KEY_EXCHANGE NID_certificate_policies SSL3_MT_ENCRYPTED_EXTENSIONS NID_client_auth SSL3_MT_END_OF_EARLY_DATA NID_code_sign SSL3_MT_FINISHED NID_commonName SSL3_MT_HELLO_REQUEST NID_countryName SSL3_MT_KEY_UPDATE NID_crlBag SSL3_MT_MESSAGE_HASH NID_crl_distribution_points SSL3_MT_NEWSESSION_TICKET NID_crl_number SSL3_MT_NEXT_PROTO NID_crl_reason SSL3_MT_SERVER_DONE NID_delta_crl SSL3_MT_SERVER_HELLO NID_des_cbc SSL3_MT_SERVER_KEY_EXCHANGE NID_des_cfb64 SSL3_MT_SUPPLEMENTAL_DATA NID_des_ecb SSL3_RT_ALERT NID_des_ede SSL3_RT_APPLICATION_DATA NID_des_ede3 SSL3_RT_CHANGE_CIPHER_SPEC NID_des_ede3_cbc SSL3_RT_HANDSHAKE NID_des_ede3_cfb64 SSL3_RT_HEADER NID_des_ede3_ofb64 SSL3_RT_INNER_CONTENT_TYPE NID_des_ede_cbc SSL3_VERSION NID_des_ede_cfb64 SSLEAY_BUILT_ON NID_des_ede_ofb64 SSLEAY_CFLAGS NID_des_ofb64 SSLEAY_DIR NID_description SSLEAY_PLATFORM NID_desx_cbc SSLEAY_VERSION NID_dhKeyAgreement ST_ACCEPT NID_dnQualifier ST_BEFORE NID_dsa ST_CONNECT NID_dsaWithSHA ST_INIT NID_dsaWithSHA1 ST_OK NID_dsaWithSHA1_2 ST_READ_BODY NID_dsa_2 ST_READ_HEADER NID_email_protect TLS1_1_VERSION NID_ext_key_usage TLS1_2_VERSION NID_ext_req TLS1_3_VERSION NID_friendlyName TLS1_VERSION NID_givenName TLSEXT_STATUSTYPE_ocsp NID_hmacWithSHA1 VERIFY_CLIENT_ONCE NID_id_ad VERIFY_FAIL_IF_NO_PEER_CERT NID_id_ce VERIFY_NONE NID_id_kp VERIFY_PEER NID_id_pbkdf2 VERIFY_POST_HANDSHAKE NID_id_pe V_OCSP_CERTSTATUS_GOOD NID_id_pkix V_OCSP_CERTSTATUS_REVOKED NID_id_qt_cps V_OCSP_CERTSTATUS_UNKNOWN NID_id_qt_unotice WRITING NID_idea_cbc X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT NID_idea_cfb64 X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS NID_idea_ecb X509_CHECK_FLAG_NEVER_CHECK_SUBJECT NID_idea_ofb64 X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS NID_info_access X509_CHECK_FLAG_NO_WILDCARDS NID_initials X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS NID_invalidity_date X509_FILETYPE_ASN1 NID_issuer_alt_name X509_FILETYPE_DEFAULT NID_keyBag X509_FILETYPE_PEM NID_key_usage X509_LOOKUP NID_localKeyID X509_PURPOSE_ANY NID_localityName X509_PURPOSE_CRL_SIGN NID_md2 X509_PURPOSE_NS_SSL_SERVER NID_md2WithRSAEncryption X509_PURPOSE_OCSP_HELPER NID_md5 X509_PURPOSE_SMIME_ENCRYPT NID_md5WithRSA X509_PURPOSE_SMIME_SIGN NID_md5WithRSAEncryption X509_PURPOSE_SSL_CLIENT NID_md5_sha1 X509_PURPOSE_SSL_SERVER NID_mdc2 X509_PURPOSE_TIMESTAMP_SIGN NID_mdc2WithRSA X509_TRUST_COMPAT NID_ms_code_com X509_TRUST_EMAIL NID_ms_code_ind X509_TRUST_OBJECT_SIGN NID_ms_ctl_sign X509_TRUST_OCSP_REQUEST NID_ms_efs X509_TRUST_OCSP_SIGN NID_ms_ext_req X509_TRUST_SSL_CLIENT NID_ms_sgc X509_TRUST_SSL_SERVER NID_name X509_TRUST_TSA NID_netscape X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH NID_netscape_base_url X509_V_ERR_AKID_SKID_MISMATCH NID_netscape_ca_policy_url X509_V_ERR_APPLICATION_VERIFICATION NID_netscape_ca_revocation_url X509_V_ERR_CA_KEY_TOO_SMALL NID_netscape_cert_extension X509_V_ERR_CA_MD_TOO_WEAK NID_netscape_cert_sequence X509_V_ERR_CERT_CHAIN_TOO_LONG NID_netscape_cert_type X509_V_ERR_CERT_HAS_EXPIRED NID_netscape_comment X509_V_ERR_CERT_NOT_YET_VALID NID_netscape_data_type X509_V_ERR_CERT_REJECTED NID_netscape_renewal_url X509_V_ERR_CERT_REVOKED NID_netscape_revocation_url X509_V_ERR_CERT_SIGNATURE_FAILURE NID_netscape_ssl_server_name X509_V_ERR_CERT_UNTRUSTED NID_ns_sgc X509_V_ERR_CRL_HAS_EXPIRED NID_organizationName X509_V_ERR_CRL_NOT_YET_VALID NID_organizationalUnitName X509_V_ERR_CRL_PATH_VALIDATION_ERROR NID_pbeWithMD2AndDES_CBC X509_V_ERR_CRL_SIGNATURE_FAILURE NID_pbeWithMD2AndRC2_CBC X509_V_ERR_DANE_NO_MATCH NID_pbeWithMD5AndCast5_CBC X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT NID_pbeWithMD5AndDES_CBC X509_V_ERR_DIFFERENT_CRL_SCOPE NID_pbeWithMD5AndRC2_CBC X509_V_ERR_EE_KEY_TOO_SMALL NID_pbeWithSHA1AndDES_CBC X509_V_ERR_EMAIL_MISMATCH NID_pbeWithSHA1AndRC2_CBC X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD NID_pbe_WithSHA1And128BitRC2_CBC X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD NID_pbe_WithSHA1And128BitRC4 X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD NID_pbe_WithSHA1And2_Key_TripleDES_CBC X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD NID_pbe_WithSHA1And3_Key_TripleDES_CBC X509_V_ERR_EXCLUDED_VIOLATION NID_pbe_WithSHA1And40BitRC2_CBC X509_V_ERR_HOSTNAME_MISMATCH NID_pbe_WithSHA1And40BitRC4 X509_V_ERR_INVALID_CA NID_pbes2 X509_V_ERR_INVALID_CALL NID_pbmac1 X509_V_ERR_INVALID_EXTENSION NID_pkcs X509_V_ERR_INVALID_NON_CA NID_pkcs3 X509_V_ERR_INVALID_POLICY_EXTENSION NID_pkcs7 X509_V_ERR_INVALID_PURPOSE NID_pkcs7_data X509_V_ERR_IP_ADDRESS_MISMATCH NID_pkcs7_digest X509_V_ERR_KEYUSAGE_NO_CERTSIGN NID_pkcs7_encrypted X509_V_ERR_KEYUSAGE_NO_CRL_SIGN NID_pkcs7_enveloped X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE NID_pkcs7_signed X509_V_ERR_NO_EXPLICIT_POLICY NID_pkcs7_signedAndEnveloped X509_V_ERR_NO_VALID_SCTS NID_pkcs8ShroudedKeyBag X509_V_ERR_OCSP_CERT_UNKNOWN NID_pkcs9 X509_V_ERR_OCSP_VERIFY_FAILED NID_pkcs9_challengePassword X509_V_ERR_OCSP_VERIFY_NEEDED NID_pkcs9_contentType X509_V_ERR_OUT_OF_MEM NID_pkcs9_countersignature X509_V_ERR_PATH_LENGTH_EXCEEDED NID_pkcs9_emailAddress X509_V_ERR_PATH_LOOP NID_pkcs9_extCertAttributes X509_V_ERR_PERMITTED_VIOLATION NID_pkcs9_messageDigest X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED NID_pkcs9_signingTime X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED NID_pkcs9_unstructuredAddress X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION NID_pkcs9_unstructuredName X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN NID_private_key_usage_period X509_V_ERR_STORE_LOOKUP NID_rc2_40_cbc X509_V_ERR_SUBJECT_ISSUER_MISMATCH NID_rc2_64_cbc X509_V_ERR_SUBTREE_MINMAX NID_rc2_cbc X509_V_ERR_SUITE_B_CANNOT_SIGN_P_384_WITH_P_256 NID_rc2_cfb64 X509_V_ERR_SUITE_B_INVALID_ALGORITHM NID_rc2_ecb X509_V_ERR_SUITE_B_INVALID_CURVE NID_rc2_ofb64 X509_V_ERR_SUITE_B_INVALID_SIGNATURE_ALGORITHM NID_rc4 X509_V_ERR_SUITE_B_INVALID_VERSION NID_rc4_40 X509_V_ERR_SUITE_B_LOS_NOT_ALLOWED NID_rc5_cbc X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY NID_rc5_cfb64 X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE NID_rc5_ecb X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE NID_rc5_ofb64 X509_V_ERR_UNABLE_TO_GET_CRL NID_ripemd160 X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER NID_ripemd160WithRSA X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT NID_rle_compression X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY NID_rsa X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE NID_rsaEncryption X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION NID_rsadsi X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION NID_safeContentsBag X509_V_ERR_UNNESTED_RESOURCE NID_sdsiCertificate X509_V_ERR_UNSPECIFIED NID_secretBag X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX NID_serialNumber X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE NID_server_auth X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE NID_sha X509_V_ERR_UNSUPPORTED_NAME_SYNTAX NID_sha1 X509_V_FLAG_ALLOW_PROXY_CERTS NID_sha1WithRSA X509_V_FLAG_CB_ISSUER_CHECK NID_sha1WithRSAEncryption X509_V_FLAG_CHECK_SS_SIGNATURE NID_shaWithRSAEncryption X509_V_FLAG_CRL_CHECK NID_stateOrProvinceName X509_V_FLAG_CRL_CHECK_ALL NID_subject_alt_name X509_V_FLAG_EXPLICIT_POLICY NID_subject_key_identifier X509_V_FLAG_EXTENDED_CRL_SUPPORT NID_surname X509_V_FLAG_IGNORE_CRITICAL NID_sxnet X509_V_FLAG_INHIBIT_ANY NID_time_stamp X509_V_FLAG_INHIBIT_MAP NID_title X509_V_FLAG_LEGACY_VERIFY NID_undef X509_V_FLAG_NOTIFY_POLICY NID_uniqueIdentifier X509_V_FLAG_NO_ALT_CHAINS NID_x509Certificate X509_V_FLAG_NO_CHECK_TIME NID_x509Crl X509_V_FLAG_PARTIAL_CHAIN NID_zlib_compression X509_V_FLAG_POLICY_CHECK NOTHING X509_V_FLAG_POLICY_MASK OCSP_RESPONSE_STATUS_INTERNALERROR X509_V_FLAG_SUITEB_128_LOS OCSP_RESPONSE_STATUS_MALFORMEDREQUEST X509_V_FLAG_SUITEB_128_LOS_ONLY OCSP_RESPONSE_STATUS_SIGREQUIRED X509_V_FLAG_SUITEB_192_LOS OCSP_RESPONSE_STATUS_SUCCESSFUL X509_V_FLAG_TRUSTED_FIRST OCSP_RESPONSE_STATUS_TRYLATER X509_V_FLAG_USE_CHECK_TIME OCSP_RESPONSE_STATUS_UNAUTHORIZED X509_V_FLAG_USE_DELTAS OPENSSL_BUILT_ON X509_V_FLAG_X509_STRICT OPENSSL_CFLAGS X509_V_OK OPENSSL_CPU_INFO XN_FLAG_COMPAT OPENSSL_DIR XN_FLAG_DN_REV OPENSSL_ENGINES_DIR XN_FLAG_DUMP_UNKNOWN_FIELDS OPENSSL_FULL_VERSION_STRING XN_FLAG_FN_ALIGN OPENSSL_INFO_CONFIG_DIR XN_FLAG_FN_LN OPENSSL_INFO_CPU_SETTINGS XN_FLAG_FN_MASK OPENSSL_INFO_DIR_FILENAME_SEPARATOR XN_FLAG_FN_NONE OPENSSL_INFO_DSO_EXTENSION XN_FLAG_FN_OID OPENSSL_INFO_ENGINES_DIR XN_FLAG_FN_SN OPENSSL_INFO_LIST_SEPARATOR XN_FLAG_MULTILINE OPENSSL_INFO_MODULES_DIR XN_FLAG_ONELINE OPENSSL_INFO_SEED_SOURCE XN_FLAG_RFC2253 OPENSSL_MODULES_DIR XN_FLAG_SEP_COMMA_PLUS OPENSSL_PLATFORM XN_FLAG_SEP_CPLUS_SPC OPENSSL_VERSION XN_FLAG_SEP_MASK OPENSSL_VERSION_MAJOR XN_FLAG_SEP_MULTILINE OPENSSL_VERSION_MINOR XN_FLAG_SEP_SPLUS_SPC OPENSSL_VERSION_NUMBER XN_FLAG_SPC_EQ OPENSSL_VERSION_PATCH

INTERNAL ONLY functions (do not use these)

The following functions are not intended for use from outside of Net::SSLeay module. They might be removed, renamed or changed without prior notice in future version.

Simply DO NOT USE THEM!

EXAMPLES

One very good example to look at is the implementation of sslcat() in the SSLeay.pm file.

The following is a simple SSLeay client (with too little error checking :-(

#!/usr/bin/perl use Socket; use Net::SSLeay qw(die_now die_if_ssl_error) ; Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); ($dest_serv, $port, $msg) = @ARGV; # Read command line $port = getservbyname ($port, tcp) unless $port =~ /^\d+$/; $dest_ip = gethostbyname ($dest_serv); $dest_serv_params = sockaddr_in($port, $dest_ip); socket (S, &AF_INET, &SOCK_STREAM, 0) or die "socket: $!"; connect (S, $dest_serv_params) or die "connect: $!"; select (S); $| = 1; select (STDOUT); # Eliminate STDIO buffering # The network connection is now open, lets fire up SSL $ctx = Net::SSLeay::CTX_new() or die_now("Failed to create SSL_CTX $!"); Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL) or die_if_ssl_error("ssl ctx set options"); $ssl = Net::SSLeay::new($ctx) or die_now("Failed to create SSL $!"); Net::SSLeay::set_fd($ssl, fileno(S)); # Must use fileno $res = Net::SSLeay::connect($ssl) and die_if_ssl_error("ssl connect"); print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "\n"; # Exchange data $res = Net::SSLeay::write($ssl, $msg); # Perl knows how long $msg is die_if_ssl_error("ssl write"); CORE::shutdown S, 1; # Half close --> No more output, sends EOF to server $got = Net::SSLeay::read($ssl); # Perl returns undef on failure die_if_ssl_error("ssl read"); print $got; Net::SSLeay::free ($ssl); # Tear down connection Net::SSLeay::CTX_free ($ctx); close S;

The following is a simple SSLeay echo server (non forking):

#!/usr/bin/perl -w use Socket; use Net::SSLeay qw(die_now die_if_ssl_error); Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); $our_ip = "\0\0\0\0"; # Bind to all interfaces $port = 1235; $sockaddr_template = S n a4 x8; $our_serv_params = pack ($sockaddr_template, &AF_INET, $port, $our_ip); socket (S, &AF_INET, &SOCK_STREAM, 0) or die "socket: $!"; bind (S, $our_serv_params) or die "bind: $!"; listen (S, 5) or die "listen: $!"; $ctx = Net::SSLeay::CTX_new () or die_now("CTX_new ($ctx): $!"); Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL) or die_if_ssl_error("ssl ctx set options"); # Following will ask password unless private key is not encrypted Net::SSLeay::CTX_use_RSAPrivateKey_file ($ctx, plain-rsa.pem, &Net::SSLeay::FILETYPE_PEM); die_if_ssl_error("private key"); Net::SSLeay::CTX_use_certificate_file ($ctx, plain-cert.pem, &Net::SSLeay::FILETYPE_PEM); die_if_ssl_error("certificate"); while (1) { print "Accepting connections...\n"; ($addr = accept (NS, S)) or die "accept: $!"; select (NS); $| = 1; select (STDOUT); # Piping hot! ($af,$client_port,$client_ip) = unpack($sockaddr_template,$addr); @inetaddr = unpack(C4,$client_ip); print "$af connection from " . join (., @inetaddr) . ":$client_port\n"; # We now have a network connection, lets fire up SSLeay... $ssl = Net::SSLeay::new($ctx) or die_now("SSL_new ($ssl): $!"); Net::SSLeay::set_fd($ssl, fileno(NS)); $err = Net::SSLeay::accept($ssl) and die_if_ssl_error(ssl accept); print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "\n"; # Connected. Exchange some data. $got = Net::SSLeay::read($ssl); # Returns undef on fail die_if_ssl_error("ssl read"); print "Got `$got (" . length ($got) . " chars)\n"; Net::SSLeay::write ($ssl, uc ($got)) or die "write: $!"; die_if_ssl_error("ssl write"); Net::SSLeay::free ($ssl); # Tear down connection close NS; }

Yet another echo server. This one runs from /etc/inetd.conf so it avoids all the socket code overhead. Only caveat is opening an rsa key file - it had better be without any encryption or else it will not know where to ask for the password. Note how STDIN and STDOUT are wired to SSL.

#!/usr/bin/perl # /etc/inetd.conf # ssltst stream tcp nowait root /path/to/server.pl server.pl # /etc/services # ssltst 1234/tcp use Net::SSLeay qw(die_now die_if_ssl_error); Net::SSLeay::load_error_strings(); Net::SSLeay::SSLeay_add_ssl_algorithms(); Net::SSLeay::randomize(); chdir /key/dir or die "chdir: $!"; $| = 1; # Piping hot! open LOG, ">>/dev/console" or die "Cant open log file $!"; select LOG; print "server.pl started\n"; $ctx = Net::SSLeay::CTX_new() or die_now "CTX_new ($ctx) ($!)"; $ssl = Net::SSLeay::new($ctx) or die_now "new ($ssl) ($!)"; Net::SSLeay::set_options($ssl, &Net::SSLeay::OP_ALL) and die_if_ssl_error("ssl set options"); # We get already open network connection from inetd, now we just # need to attach SSLeay to STDIN and STDOUT Net::SSLeay::set_rfd($ssl, fileno(STDIN)); Net::SSLeay::set_wfd($ssl, fileno(STDOUT)); Net::SSLeay::use_RSAPrivateKey_file ($ssl, plain-rsa.pem, Net::SSLeay::FILETYPE_PEM); die_if_ssl_error("private key"); Net::SSLeay::use_certificate_file ($ssl, plain-cert.pem, Net::SSLeay::FILETYPE_PEM); die_if_ssl_error("certificate"); Net::SSLeay::accept($ssl) and die_if_ssl_err("ssl accept: $!"); print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "\n"; $got = Net::SSLeay::read($ssl); die_if_ssl_error("ssl read"); print "Got `$got (" . length ($got) . " chars)\n"; Net::SSLeay::write ($ssl, uc($got)) or die "write: $!"; die_if_ssl_error("ssl write"); Net::SSLeay::free ($ssl); # Tear down the connection Net::SSLeay::CTX_free ($ctx); close LOG;

There are also a number of example/test programs in the examples directory:

sslecho.pl - A simple server, not unlike the one above minicli.pl - Implements a client using low level SSLeay routines sslcat.pl - Demonstrates using high level sslcat utility function get_page.pl - Is a utility for getting html pages from secure servers callback.pl - Demonstrates certificate verification and callback usage stdio_bulk.pl - Does SSL over Unix pipes ssl-inetd-serv.pl - SSL server that can be invoked from inetd.conf httpd-proxy-snif.pl - Utility that allows you to see how a browser sends https request to given server and what reply it gets back (very educative :-) makecert.pl - Creates a self signed cert (does not use this module)

INSTALLATION

See README and README.* in the distribution directory for installation guidance on a variety of platforms.

LIMITATIONS

Net::SSLeay::read() uses an internal buffer of 32KB, thus no single read will return more. In practice one read returns much less, usually as much as fits in one network packet. To work around this, you should use a loop like this:

$reply = ; while ($got = Net::SSLeay::read($ssl)) { last if print_errs(SSL_read); $reply .= $got; }

Although there is no built-in limit in Net::SSLeay::write(), the network packet size limitation applies here as well, thus use:

$written = 0; while ($written < length($message)) { $written += Net::SSLeay::write($ssl, substr($message, $written)); last if print_errs(SSL_write); }

Or alternatively you can just use the following convenience functions:

Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write failure"; $got = Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure";

KNOWN BUGS AND CAVEATS

LibreSSL versions in the 3.1 - 3.3 series contain a TLS 1.3 implementation that is not fully compatible with the libssl API, but is still advertised during protocol auto-negotiation. If you encounter problems or unexpected behaviour with SSL or SSL_CTX objects whose protocol version was automatically negotiated and libssl is provided by any of these versions of LibreSSL, it could be because the peers negotiated to use TLS 1.3 - try setting the maximum protocol version to TLS 1.2 (via Net::SSLeay::set_max_proto_version() or Net::SSLeay::CTX_set_max_proto_version()) before establishing the connection. The first stable LibreSSL version with a fully libssl-compatible TLS 1.3 implementation is 3.4.1.

An OpenSSL bug CVE-2015-0290 OpenSSL Multiblock Corrupted Pointer Issue can cause POST requests of over 90kB to fail or crash. This bug is reported to be fixed in OpenSSL 1.0.2a.

Autoloader emits a

Argument "xxx" isnt numeric in entersub at blib/lib/Net/SSLeay.pm

warning if die_if_ssl_error is made autoloadable. If you figure out why, drop me a line.

Callback set using SSL_set_verify() does not appear to work. This may well be an openssl problem (e.g. see ssl/ssl_lib.c line 1029). Try using SSL_CTX_set_verify() instead and do not be surprised if even this stops working in future versions.

Callback and certificate verification stuff is generally too little tested.

Random numbers are not initialized randomly enough, especially if you do not have /dev/random and/or /dev/urandom (such as in Solaris platforms - but it's been suggested that cryptorand daemon from the SUNski package solves this). In this case you should investigate third party software that can emulate these devices, e.g. by way of a named pipe to some program.

Another gotcha with random number initialization is randomness depletion. This phenomenon, which has been extensively discussed in OpenSSL, Apache-SSL, and Apache-mod_ssl forums, can cause your script to block if you use /dev/random or to operate insecurely if you use /dev/urandom. What happens is that when too much randomness is drawn from the operating system's randomness pool then randomness can temporarily be unavailable. /dev/random solves this problem by waiting until enough randomness can be gathered - and this can take a long time since blocking reduces activity in the machine and less activity provides less random events: a vicious circle. /dev/urandom solves this dilemma more pragmatically by simply returning predictable random numbers. Some /dev/urandom emulation software however actually seems to implement /dev/random semantics. Caveat emptor.

I've been pointed to two such daemons by Mik Firestone <mik@@speed.stdio._com> who has used them on Solaris 8:

  1. Entropy Gathering Daemon (EGD) at <http://www.lothar.com/tech/crypto/>

  2. Pseudo-random number generating daemon (PRNGD) at <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html>

If you are using the low level API functions to communicate with other SSL implementations, you would do well to call

Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL) or die_if_ssl_error("ssl ctx set options");

to cope with some well know bugs in some other SSL implementations. The high level API functions always set all known compatibility options.

Sometimes sslcat() (and the high level HTTPS functions that build on it) is too fast in signaling the EOF to legacy HTTPS servers. This causes the server to return empty page. To work around this problem you can set the global variable

$Net::SSLeay::slowly = 1; # Add sleep so broken servers can keep up

HTTP/1.1 is not supported. Specifically this module does not know to issue or serve multiple http requests per connection. This is a serious shortcoming, but using the SSL session cache on your server helps to alleviate the CPU load somewhat.

As of version 1.09 many newer OpenSSL auxiliary functions were added (from REM_AUTOMATICALLY_GENERATED_1_09 onwards in SSLeay.xs). Unfortunately I have not had any opportunity to test these. Some of them are trivial enough that I believe they just work, but others have rather complex interfaces with function pointers and all. In these cases you should proceed wit great caution.

This module defaults to using OpenSSL automatic protocol negotiation code for automatically detecting the version of the SSL/TLS protocol that the other end talks. With most web servers this works just fine, but once in a while I get complaints from people that the module does not work with some web servers. Usually this can be solved by explicitly setting the protocol version, e.g.

$Net::SSLeay::ssl_version = 2; # Insist on SSLv2 $Net::SSLeay::ssl_version = 3; # Insist on SSLv3 $Net::SSLeay::ssl_version = 10; # Insist on TLSv1 $Net::SSLeay::ssl_version = 11; # Insist on TLSv1.1 $Net::SSLeay::ssl_version = 12; # Insist on TLSv1.2 $Net::SSLeay::ssl_version = 13; # Insist on TLSv1.3

Although the autonegotiation is nice to have, the SSL standards do not formally specify any such mechanism. Most of the world has accepted the SSLeay/OpenSSL way of doing it as the de facto standard. But for the few that think differently, you have to explicitly speak the correct version. This is not really a bug, but rather a deficiency in the standards. If a site refuses to respond or sends back some nonsensical error codes (at the SSL handshake level), try this option before mailing me.

On some systems, OpenSSL may be compiled without support for SSLv2. If this is the case, Net::SSLeay will warn if ssl_version has been set to 2.

The high level API returns the certificate of the peer, thus allowing one to check what certificate was supplied. However, you will only be able to check the certificate after the fact, i.e. you already sent your form data by the time you find out that you did not trust them, oops.

So, while being able to know the certificate after the fact is surely useful, the security minded would still choose to do the connection and certificate verification first and only then exchange data with the site. Currently none of the high level API functions do this, thus you would have to program it using the low level API. A good place to start is to see how the Net::SSLeay::http_cat() function is implemented.

The high level API functions use a global file handle SSLCAT_S internally. This really should not be a problem because there is no way to interleave the high level API functions, unless you use threads (but threads are not very well supported in perl anyway). However, you may run into problems if you call undocumented internal functions in an interleaved fashion. The best solution is to require Net::SSLeay in one thread after all the threads have been created.

DIAGNOSTICS

Random number generator not seeded!!!

(W) This warning indicates that randomize() was not able to read /dev/random or /dev/urandom, possibly because your system does not have them or they are differently named. You can still use SSL, but the encryption will not be as strong.

open_tcp_connection: destination host not found:`server' (port 123) ($!)

Name lookup for host named server failed.

open_tcp_connection: failed `server', 123 ($!)

The name was resolved, but establishing the TCP connection failed.

msg 123: 1 - error:140770F8:SSL routines:SSL23_GET_SERVER_HELLO:unknown proto

SSLeay error string. The first number (123) is the PID, the second number (1) indicates the position of the error message in SSLeay error stack. You often see a pile of these messages as errors cascade.

msg 123: 1 - error:02001002::lib (2) :func (1) :reason (2)

The same as above, but you didn't call load_error_strings() so SSLeay couldn't verbosely explain the error. You can still find out what it means with this command: /usr/local/ssl/bin/ssleay errstr 02001002

Password is being asked for private key

This is normal behaviour if your private key is encrypted. Either you have to supply the password or you have to use an unencrypted private key. Scan OpenSSL.org for the FAQ that explains how to do this (or just study examples/makecert.pl which is used during make test to do just that).

SECURITY

You can mitigate some of the security vulnerabilities that might be present in your SSL/TLS application:

BEAST Attack

http://blogs.cisco.com/security/beat-the-beast-with-tls/ https://community.qualys.com/blogs/securitylabs/2011/10/17/mitigating-the-beast-attack-on-tls http://blog.zoller.lu/2011/09/beast-summary-tls-cbc-countermeasures.html

The BEAST attack relies on a weakness in the way CBC mode is used in SSL/TLS. In OpenSSL versions 0.9.6d and later, the protocol-level mitigation is enabled by default, thus making it not vulnerable to the BEAST attack.

Solutions:

Net::SSLeay::set_cipher_list($ssl, 'RC4-SHA:HIGH:!ADH');

Session Resumption

http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html

The SSL Labs vulnerability test on your SSL server might report in red:

Session resumption No (IDs assigned but not accepted)

This report is not really bug or a vulnerability, since the server will not accept session resumption requests. However, you can prevent this noise in the report by disabling the session cache altogether: Net::SSLeay::CTX_set_session_cache_mode($ssl_ctx, Net::SSLeay::SESS_CACHE_OFF()); Use 0 if you don't have SESS_CACHE_OFF constant.

Secure Renegotiation and DoS Attack

https://community.qualys.com/blogs/securitylabs/2011/10/31/tls-renegotiation-and-denial-of-service-attacks

This is not a security flaw, it is more of a DoS vulnerability.

Solutions:

BUGS

If you encounter a problem with this module that you believe is a bug, please create a new issue <https://github.com/radiator-software/p5-net-ssleay/issues/new> in the Net-SSLeay GitHub repository. Please make sure your bug report includes the following information:

AUTHOR

Originally written by Sampo Kellomäki.

Maintained by Florian Ragwitz between November 2005 and January 2010.

Maintained by Mike McCauley between November 2005 and June 2018.

Maintained by Chris Novakovic, Tuure Vartiainen and Heikki Vatiainen since June 2018.

COPYRIGHT

Copyright (c) 1996-2003 Sampo Kellomäki <sampo@iki.fi>

Copyright (c) 2005-2010 Florian Ragwitz <rafl@debian.org>

Copyright (c) 2005-2018 Mike McCauley <mikem@airspayce.com>

Copyright (c) 2018- Chris Novakovic <chris@chrisn.me.uk>

Copyright (c) 2018- Tuure Vartiainen <vartiait@radiatorsoftware.com>

Copyright (c) 2018- Heikki Vatiainen <hvn@radiatorsoftware.com>

All rights reserved.

LICENSE

This module is released under the terms of the Artistic License 2.0. For details, see the LICENSE file distributed with Net-SSLeay's source code.

SEE ALSO

Net::SSLeay::Handle - File handle interface ./examples - Example servers and a clients <http://www.openssl.org/> - OpenSSL source, documentation, etc openssl-users-request@openssl.org - General OpenSSL mailing list <http://www.ietf.org/rfc/rfc2246.txt> - TLS 1.0 specification <http://www.w3c.org> - HTTP specifications <http://www.ietf.org/rfc/rfc2617.txt> - How to send password <http://www.lothar.com/tech/crypto/> - Entropy Gathering Daemon (EGD) <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html> - pseudo-random number generating daemon (PRNGD) perl(1) perlref(1) perllol(1) perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod