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S2S-TLS: Convert SSL.txt to Markdown and update information given
No longer describe creating self-signed certificates or using "stunnel", as both is not recommended.
This commit is contained in:
Alexander Barton
parent
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b826fad158
@ -386,7 +386,7 @@ standard locations.
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- `--with-gnutls[=<path>]`
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Enable support for SSL/TLS using OpenSSL or GnuTLS libraries.
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See `doc/SSL.txt` for details.
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See `doc/SSL.md` for details.
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- IPv6 (autodetected by default):
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@ -34,7 +34,7 @@ static_docs = \
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README-Interix.txt \
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RFC.txt \
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Services.txt \
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SSL.txt
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SSL.md
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doc_templates = sample-ngircd.conf.tmpl
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@ -120,3 +120,7 @@ with the `;` character), but it is a good idea to enable it whenever possible!
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And you can have as many *Operator blocks* as you like, configuring multiple
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different IRC Operators.
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## Configuring SSL/TLS Encryption
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Please see the file `SSL.md` for details.
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80
doc/SSL.md
Normal file
80
doc/SSL.md
Normal file
@ -0,0 +1,80 @@
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# [ngIRCd](https://ngircd.barton.de) - SSL/TLS Encrypted Connections
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ngIRCd supports SSL/TLS encrypted connections using the *OpenSSL* or *GnuTLS*
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libraries. Both encrypted server-server links as well as client-server links
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are supported.
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SSL is a compile-time option which is disabled by default. Use one of these
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options of the ./configure script to enable it:
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- `--with-openssl`: enable SSL support using OpenSSL.
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- `--with-gnutls`: enable SSL support using GnuTLS.
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You can check the output of `ngircd --version` to validate if your executable
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includes support for SSL or not: "+SSL" must be listed in the feature flags.
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You also need a SSL key and certificate, for example using Let's Encrypt, which
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is out of the scope of this document.
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From a feature point of view, ngIRCds support for both libraries is
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comparable. The only major difference (at this time) is that ngIRCd with GnuTLS
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does not support password protected private keys.
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## Configuration
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SSL-encrypted connections and plain-text connects can't run on the same network
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port (which is a limitation of the IRC protocol); therefore you have to define
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separate port(s) in your `[SSL]` block in the configuration file.
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A minimal configuration for *accepting* SSL-encrypted client & server
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connections looks like this:
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``` ini
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[SSL]
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CertFile = /etc/ssl/certs/my-fullchain.pem
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KeyFile = /etc/ssl/certs/my-privkey.pem
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Ports = 6697, 6698
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```
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In this case, the server only deals with *incoming* connections and never has to
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validate SSL certificates itself, and therefore no "Certificate Authorities" are
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needed.
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If you want to use *outgoing* SSL-connections to other servers, you need to add:
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``` ini
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[SSL]
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...
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CAFile = /etc/ssl/certs/ca-certificates.crt
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DHFile = /etc/ngircd/dhparams.pem
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[SERVER]
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...
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SSLConnect = yes
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```
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The `CAFile` option configures a file listing all the certificates of the
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trusted Certificate Authorities.
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The Diffie-Hellman parameters file `dhparams.pem` can be created like this:
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- OpenSSL: `openssl dhparam -2 -out /etc/ngircd/dhparams.pem 4096`
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- GnuTLS: `certtool --generate-dh-params --bits 4096 --outfile /etc/ngircd/dhparams.pem`
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Note that enabling `SSLConnect` not only enforces SSL-encrypted links for
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*outgoing* connections to other servers, but for *incoming* connections as well:
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If a server configured with `SSLConnect = yes` tries to connect on a plain-text
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connection, it won't be accepted to prevent data leakage! Therefore you should
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set this for *all* servers you expect to use SSL-encrypted connections!
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## Accepting untrusted Remote Certificates
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If you are using self-signed certificates or otherwise invalid certificates,
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which ngIRCd would reject by default, you can force ngIRCd to skip certificate
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validation on a per-server basis and continue establishing outgoing connections
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to the respective peer by setting `SSLVerify = no` in the `[SERVER]` block of
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this remote server in your configuration.
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But please think twice before doing so: the established connection is still
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encrypted but the remote site is *not verified at all* and man-in-the-middle
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attacks are possible!
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108
doc/SSL.txt
108
doc/SSL.txt
@ -1,108 +0,0 @@
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ngIRCd - Next Generation IRC Server
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(c)2001-2008 Alexander Barton,
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alex@barton.de, http://www.barton.de/
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ngIRCd is free software and published under the
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terms of the GNU General Public License.
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-- SSL.txt --
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ngIRCd supports SSL/TLSv1 encrypted connections using the OpenSSL or GnuTLS
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libraries. Both encrypted server-server links as well as client-server links
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are supported.
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SSL is a compile-time option which is disabled by default. Use one of these
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options of the ./configure script to enable it:
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--with-openssl enable SSL support using OpenSSL
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--with-gnutls enable SSL support using GnuTLS
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You also need a key/certificate, see below for how to create a self-signed one.
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From a feature point of view, ngIRCds support for both libraries is
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comparable. The only major difference (at this time) is that ngircd with gnutls
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does not support password protected private keys.
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Configuration
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~~~~~~~~~~~~~
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To enable SSL connections a separate port must be configured: it is NOT
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possible to handle unencrypted and encrypted connections on the same port!
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This is a limitation of the IRC protocol ...
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You have to set (at least) the following configuration variables in the
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[SSL] section of ngircd.conf(5): Ports, KeyFile, and CertFile.
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Now IRC clients are able to connect using SSL on the configured port(s).
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(Using port 6697 for encrypted connections is common.)
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To enable encrypted server-server links, you have to additionally set
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SSLConnect to "yes" in the corresponding [SERVER] section.
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Creating a self-signed certificate
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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OpenSSL:
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Creating a self-signed certificate and key:
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$ openssl req -newkey rsa:2048 -x509 -keyout server-key.pem -out server-cert.pem -days 1461
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Create DH parameters (optional):
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$ openssl dhparam -2 -out dhparams.pem 4096
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GnuTLS:
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Creating a self-signed certificate and key:
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$ certtool --generate-privkey --bits 2048 --outfile server-key.pem
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$ certtool --generate-self-signed --load-privkey server-key.pem --outfile server-cert.pem
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Create DH parameters (optional):
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$ certtool --generate-dh-params --bits 4096 --outfile dhparams.pem
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Alternate approach using stunnel(1)
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Alternatively (or if you are using ngIRCd compiled without support
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for GnuTLS/OpenSSL), you can use external programs/tools like stunnel(1) to
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get SSL encrypted connections:
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<http://stunnel.mirt.net/>
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<http://www.stunnel.org/>
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Stefan Sperling (stefan at binarchy dot net) mailed the following text as a
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short "how-to", thanks Stefan!
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=== snip ===
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! This guide applies to stunnel 4.x !
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Put this in your stunnel.conf:
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[ircs]
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accept = 6667
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connect = 6668
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This makes stunnel listen for incoming connections
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on port 6667 and forward decrypted data to port 6668.
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We call the connection 'ircs'. Stunnel will use this
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name when logging connection attempts via syslog.
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You can also use the name in /etc/hosts.{allow,deny}
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if you run tcp-wrappers.
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To make sure ngircd is listening on the port where
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the decrypted data arrives, set
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Ports = 6668
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in your ngircd.conf.
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Start stunnel and restart ngircd.
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That's it.
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Don't forget to activate ssl support in your irc client ;)
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The main drawback of this approach compared to using builtin ssl
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is that from ngIRCds point of view, all ssl-enabled client connections will
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originate from the host running stunnel.
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=== snip ===
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