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Signed SSL certificate: Difference between revisions

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>IotaSpencer
Fixed "since the root certificate is probably not known on your machine"
changed /var/lib/znc to /var/lib/znc/.znc in several examples to better reflect common paths used in ZNC packages. noted by predicament in #znc
 
(22 intermediate revisions by 8 users not shown)
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If you're not going to be the only person using the ZNC instance, you may want to consider using signed SSL certificates.  Signed SSL certificates are generated by third-party companies, such as [https://www.startssl.com/ StartSSL], [http://www.positivessl.com/ PositiveSSL], [http://www.verisign.com/ VeriSign], or others, and will not cause "self-signed certificate" errors when used with an IRC client.
Signed SSL certificates are recommended when more than one person uses the ZNC instance.  Signed SSL certificates are generated by third-party companies, such as [https://letsencrypt.org/ Let's Encrypt], [http://www.positivessl.com/ PositiveSSL], [http://www.verisign.com/ VeriSign], or others, and will not cause "self-signed certificate" errors when used with an IRC client.


== General advice ==
== General advice ==


<code>znc.pem</code> '''must''' contain everything in order from the "most private" to the "most public" key.
Make sure that the certificate private key file is not encrypted and does not have password protection on it, ZNC is unable to properly handle encrypted private key files.


E.g. it may be something like this, if CA provides only 1 root cert in the chain:
=== ZNC 1.7.0+ ===


  cat your-certificate-private.key > znc.pem
Since 1.7, you can configure ZNC to read different parts of the certificate from different files:
  cat your-certificate.crt >> znc.pem
 
cat ca-root.crt >> znc.pem
SSLCertFile = /path/to/combined/cert.pem
  SSLKeyFile = /path/to/private/key.pem
  SSLDHParamFile = /path/to/DH/file.pem
 
Read [[Configuration]] about how to edit config.
 
The old way (described below) still works.
 
=== Before ZNC 1.7 ===


Below you may find more specific instructions how to configure certs from few CAs, contributed by various people.
<code>znc.pem</code> '''must''' contain everything in order from the "most private" to the "most public" entries, except for the root certificate.


== StartSSL ==
E.g. it may be something like this:


If you want to use your StartSSL web server certificate in ZNC, you need to put your private key and then your certificate into ~/.znc/znc.pem:
cat your-certificate-private.key > znc.pem
cat your-certificate.crt >> znc.pem
cat intermediate-certificate-of-ca.crt >> znc.pem  # If your certificate wasn't signed by CA root certificate directly.
# cat ca-root.crt >> znc.pem # Possible, but useless. If client knows this CA, this is redundant. If client doesn't know this CA, it's not trusted anyway.


<code>cat server.key znc.pem > znc.pem</code>
You should also generate the Diffie–Hellman key exchange parameters, also appended to znc.pem:


Remember to replace server.key and znc.pem with the correct filenames and relevant paths.
openssl dhparam -out dhparam.pem 2048
cat dhparam.pem >> znc.pem


The certificate now gets validated, but the validation fails, since the root certificate is probably not known on your machine (while most browser come built-in with the root certificate). So you either make the certificate known to your machine (and all your ZNC users) or your put the root cert into your znc.pem file like the following:
The dhparam file doesn't have to be kept secret, and can be used multiple times; substitute 2048 for your private key's bit size.


# <code>cd ~/.znc/</code>
To apply this new certificate file to ZNC, just put (replace) it in ZNC's work folder.<br/>
# <code>wget https://www.startssl.com/certs/sub.class1.server.ca.pem -O startssl.com.root.pem</code>
As of 1.6.2, ZNC will reload <code>znc.pem</code> each time a client connects, but it'll be fixed in future.
# <code>cat startssl.com.root.pem >> znc.pem</code>


It seems the order in your znc.pem must be "key", "own cert" and "root cert". If you get connection errors, make sure you done it right. You can test your certificate without connecting to znc with the following command:
Below you may find more specific instructions how to configure certs from few CAs, contributed by various people.


<code>openssl s_client -showcerts -connect domain.tld:6667</code>
== CA-specific application of the general advice above ==
Change the domain and port to your domain and znc's listening port.
:Why this section is even needed?... --[[User:DarthGandalf|DarthGandalf]] ([[User talk:DarthGandalf|talk]]) 09:11, 4 December 2015 (UTC)


== PositiveSSL ==
=== PositiveSSL ===


This is how I created a Positive SSL certificate for znc.
This is how I ([[User:Wayne_Arthurton|Wayne_Arthurton]]) created a Positive SSL certificate for znc.


# <code>openssl req -nodes -newkey rsa:2048 -keyout myserver.key -out server.csr</code>
# <code>openssl req -nodes -newkey rsa:2048 -keyout myserver.key -out server.csr</code>
Line 47: Line 58:


To use a PositiveSSL, this seemed to be the recipe
To use a PositiveSSL, this seemed to be the recipe
=== LetsEncrypt ===
'''Caveat:''' Let's Encrypt does not currently support IP addresses, if you want to use a Let's Encrypt certificate you'll need to be on a (sub-)domain. Additionally, they have a 90-day expiry, so it's a good idea to set up a cron job to reissue a cert every so often (monthly works).
==== Certbot ====
If you're using the official Let's Encrypt client, assuming you have your certificate in ''/etc/letsencrypt/live/example.org/'', here is how you can make a ''znc.pem'' from it (concatenate the 2 files together):
cat /etc/letsencrypt/live/example.org/{privkey,fullchain}.pem > znc.pem
If you are using an older version of the Let's Encrypt client that does not create fullchain.pem, use this one:
cat /etc/letsencrypt/live/example.org/{privkey,cert,chain}.pem > znc.pem
You need to repeat this every time you obtain a new certificate.
===== Automating znc.pem creation =====
You can automate the process of creating a <code>znc.pem</code> file every time your certificate is renewed by adding a deploy hook to <code>/etc/letsencrypt/renewal-hooks/deploy</code> like so:
<pre>
$ cd /etc/letsencrypt/renewal-hooks/deploy
$ touch update-znc.pem
$ chmod +x update-znc.pem
$ vim update-znc.pem
</pre>
<pre>
#!/bin/bash
YOURDOMAIN="example.com"
[[ $RENEWED_LINEAGE != "/etc/letsencrypt/live/$YOURDOMAIN" ]] && exit 0
echo "Updating certs"
cat /etc/letsencrypt/live/$YOURDOMAIN/{privkey,fullchain}.pem > /var/lib/znc/.znc/znc.pem
</pre>
==== Caddy ====
[https://caddyserver.com/ Caddy] is a web server (alike Apache or nginx) with automatic HTTPS through LetsEncrypt.
The certificate files generated through Caddy can be used for ZNC, although they have to be concatenated just like with the official client.
Here's how you can make a ''znc.pem'' from them:
cat /etc/ssl/caddy/.caddy/acme/acme-v01.api.letsencrypt/sites/example.org/example.org.{key,crt} > /var/lib/znc/.znc/znc.pem
Just like with the official client, you will need to repeat this every time Caddy obtains a new certificate.
This can be automated to copy every month using a cronjob, like so:
0 0 1 * * cat /etc/ssl/caddy/.caddy/acme/acme-v01.api.letsencrypt/sites/example.org/example.org.{key,crt} > /var/lib/znc/.znc/znc.pem
==== Alternative Setup ====
This is a very quick install using a small, dependency-free, auditable python script: [https://github.com/diafygi/acme-tiny acme-tiny]. I recommend working in a separate directory, and then moving/symlinking the final cert into the config file afterward.
First, generate some RSA keys. The account key is your letsencrypt account, and can be reused for multiple domain keys if you're managing a lot of servers. For a private install it's easiest to just generate a new throwaway. Do replace <nowiki>yoursite.com</nowiki> with the appropriate value, here.
openssl genrsa 4096 > account.key
openssl genrsa 4096 > domain.key
openssl req -new -sha256 -key domain.key -subj "/CN=yoursite.com" > domain.csr
Next, we need to set up a challenge-response folder available from port 80. If your server has a web server available you'll need to hook into it temporarily (see the docs on the acme-tiny repo). If you do not have a web server, you can spin up a temporary one with python:
mkdir -p .well-known/acme-challenge/
sudo python -m SimpleHTTPServer 80 &
Now, download that script (and audit it if you're paranoid about malicious code), and run it get your signed cert. Then, we pull down the cross-signed cert to build our certificate chain, and smush all the files together for our final znc.pem:
python acme_tiny.py \
  --account-key ./account.key \
  --csr ./domain.csr \
  --acme-dir ./.well-known/acme-challenge/ \
  > ./signed.crt
wget <nowiki>https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.pem</nowiki>
cat domain.key signed.crt lets-encrypt-x3-cross-signed.pem > znc.pem
Don't forget to kill the temporary web server if you started it up, and then copy/symlink the certificate into place.
If you want/need to set up automatic renewals, you'll probably need to set up a permanent web server hosting the acme-challenge folder, and otherwise the shell script is identical to the last code block above,
except with absolute paths.
=== CACert ===
To use a [http://www.cacert.org CACert] certificate, you need to do several things.  Within a dedicated folder for this, do the following steps:
#. Create an '''unencrypted''' key for the server and the corresponding CSR: <code>openssl req -nodes -newkey rsa:2048 -keyout server.key -out server.csr</code>
#. Send the CSR to CACert and wait for them to issue you a certificate.  Once you retrieve the certificate in text format from their site, copy that text and put it into the file called <code>server.crt</code>
#. Download both the [https://www.cacert.org/certs/root.crt CACert Root CA certificate] and the [https://www.cacert.org/certs/class3.crt CACert Intermediate certificate] to the same folder.
#. As per the 'general' advice above, create DH parameters to include with the certificate ('''Warning: this will take some time to complete'''): <code>openssl dhparam 2048 -out dh2048.pem</code>
#. Concatenate all the certificates and the key together with the following code: <code>cat server.key server.crt class3.crt root.crt dh2048.pem > znc.pem</code>
#. Take the complete <code>znc.pem</code> file and put it in the ZNC configuration directory, overwriting any preexisting <code>znc.pem</code> file in the directory (or move the <code>znc.pem</code> file to another name and create a new <code>znc.pem</code> file with the certificate from CACert).
Once this is completed you can now use the CACert certificate for your ZNC.

Latest revision as of 17:19, 25 February 2022

Signed SSL certificates are recommended when more than one person uses the ZNC instance. Signed SSL certificates are generated by third-party companies, such as Let's Encrypt, PositiveSSL, VeriSign, or others, and will not cause "self-signed certificate" errors when used with an IRC client.

General advice

Make sure that the certificate private key file is not encrypted and does not have password protection on it, ZNC is unable to properly handle encrypted private key files.

ZNC 1.7.0+

Since 1.7, you can configure ZNC to read different parts of the certificate from different files:

SSLCertFile = /path/to/combined/cert.pem
SSLKeyFile = /path/to/private/key.pem
SSLDHParamFile = /path/to/DH/file.pem

Read Configuration about how to edit config.

The old way (described below) still works.

Before ZNC 1.7

znc.pem must contain everything in order from the "most private" to the "most public" entries, except for the root certificate.

E.g. it may be something like this:

cat your-certificate-private.key > znc.pem
cat your-certificate.crt >> znc.pem
cat intermediate-certificate-of-ca.crt >> znc.pem  # If your certificate wasn't signed by CA root certificate directly.
# cat ca-root.crt >> znc.pem  # Possible, but useless. If client knows this CA, this is redundant. If client doesn't know this CA, it's not trusted anyway.

You should also generate the Diffie–Hellman key exchange parameters, also appended to znc.pem:

openssl dhparam -out dhparam.pem 2048
cat dhparam.pem >> znc.pem

The dhparam file doesn't have to be kept secret, and can be used multiple times; substitute 2048 for your private key's bit size.

To apply this new certificate file to ZNC, just put (replace) it in ZNC's work folder.
As of 1.6.2, ZNC will reload znc.pem each time a client connects, but it'll be fixed in future.

Below you may find more specific instructions how to configure certs from few CAs, contributed by various people.

CA-specific application of the general advice above

Why this section is even needed?... --DarthGandalf (talk) 09:11, 4 December 2015 (UTC)

PositiveSSL

This is how I (Wayne_Arthurton) created a Positive SSL certificate for znc.

  1. openssl req -nodes -newkey rsa:2048 -keyout myserver.key -out server.csr
  2. Submit server.csr to PositiveSSL
  3. Once you receive your SSL Bundle zip, uncompress
  4. cat myserver.key > ~/.znc/znc.pem
  5. cat host_domain_com.crt >> ~/.znc/znc.pem
  6. cat PositiveSSLCA2.crt >> ~/.znc/znc.pem
  7. cat AddTrustExternalCARoot.crt >> ~/.znc/znc.pem

That should do it. Drop a note on my Wiki Page if you need any more help.

To use a PositiveSSL, this seemed to be the recipe

LetsEncrypt

Caveat: Let's Encrypt does not currently support IP addresses, if you want to use a Let's Encrypt certificate you'll need to be on a (sub-)domain. Additionally, they have a 90-day expiry, so it's a good idea to set up a cron job to reissue a cert every so often (monthly works).

Certbot

If you're using the official Let's Encrypt client, assuming you have your certificate in /etc/letsencrypt/live/example.org/, here is how you can make a znc.pem from it (concatenate the 2 files together):

cat /etc/letsencrypt/live/example.org/{privkey,fullchain}.pem > znc.pem

If you are using an older version of the Let's Encrypt client that does not create fullchain.pem, use this one:

cat /etc/letsencrypt/live/example.org/{privkey,cert,chain}.pem > znc.pem

You need to repeat this every time you obtain a new certificate.

Automating znc.pem creation

You can automate the process of creating a znc.pem file every time your certificate is renewed by adding a deploy hook to /etc/letsencrypt/renewal-hooks/deploy like so:

$ cd /etc/letsencrypt/renewal-hooks/deploy
$ touch update-znc.pem
$ chmod +x update-znc.pem
$ vim update-znc.pem
#!/bin/bash
YOURDOMAIN="example.com"
 
[[ $RENEWED_LINEAGE != "/etc/letsencrypt/live/$YOURDOMAIN" ]] && exit 0
echo "Updating certs"
cat /etc/letsencrypt/live/$YOURDOMAIN/{privkey,fullchain}.pem > /var/lib/znc/.znc/znc.pem

Caddy

Caddy is a web server (alike Apache or nginx) with automatic HTTPS through LetsEncrypt. The certificate files generated through Caddy can be used for ZNC, although they have to be concatenated just like with the official client.

Here's how you can make a znc.pem from them:

cat /etc/ssl/caddy/.caddy/acme/acme-v01.api.letsencrypt/sites/example.org/example.org.{key,crt} > /var/lib/znc/.znc/znc.pem

Just like with the official client, you will need to repeat this every time Caddy obtains a new certificate. This can be automated to copy every month using a cronjob, like so:

0 0 1 * * cat /etc/ssl/caddy/.caddy/acme/acme-v01.api.letsencrypt/sites/example.org/example.org.{key,crt} > /var/lib/znc/.znc/znc.pem

Alternative Setup

This is a very quick install using a small, dependency-free, auditable python script: acme-tiny. I recommend working in a separate directory, and then moving/symlinking the final cert into the config file afterward.

First, generate some RSA keys. The account key is your letsencrypt account, and can be reused for multiple domain keys if you're managing a lot of servers. For a private install it's easiest to just generate a new throwaway. Do replace yoursite.com with the appropriate value, here.

openssl genrsa 4096 > account.key
openssl genrsa 4096 > domain.key
openssl req -new -sha256 -key domain.key -subj "/CN=yoursite.com" > domain.csr

Next, we need to set up a challenge-response folder available from port 80. If your server has a web server available you'll need to hook into it temporarily (see the docs on the acme-tiny repo). If you do not have a web server, you can spin up a temporary one with python:

mkdir -p .well-known/acme-challenge/
sudo python -m SimpleHTTPServer 80 &

Now, download that script (and audit it if you're paranoid about malicious code), and run it get your signed cert. Then, we pull down the cross-signed cert to build our certificate chain, and smush all the files together for our final znc.pem:

python acme_tiny.py \
  --account-key ./account.key \
  --csr ./domain.csr \
  --acme-dir ./.well-known/acme-challenge/ \
  > ./signed.crt

wget https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.pem
cat domain.key signed.crt lets-encrypt-x3-cross-signed.pem > znc.pem

Don't forget to kill the temporary web server if you started it up, and then copy/symlink the certificate into place.

If you want/need to set up automatic renewals, you'll probably need to set up a permanent web server hosting the acme-challenge folder, and otherwise the shell script is identical to the last code block above, except with absolute paths.

CACert

To use a CACert certificate, you need to do several things. Within a dedicated folder for this, do the following steps:

  1. . Create an unencrypted key for the server and the corresponding CSR: openssl req -nodes -newkey rsa:2048 -keyout server.key -out server.csr
  2. . Send the CSR to CACert and wait for them to issue you a certificate. Once you retrieve the certificate in text format from their site, copy that text and put it into the file called server.crt
  3. . Download both the CACert Root CA certificate and the CACert Intermediate certificate to the same folder.
  4. . As per the 'general' advice above, create DH parameters to include with the certificate (Warning: this will take some time to complete): openssl dhparam 2048 -out dh2048.pem
  5. . Concatenate all the certificates and the key together with the following code: cat server.key server.crt class3.crt root.crt dh2048.pem > znc.pem
  6. . Take the complete znc.pem file and put it in the ZNC configuration directory, overwriting any preexisting znc.pem file in the directory (or move the znc.pem file to another name and create a new znc.pem file with the certificate from CACert).

Once this is completed you can now use the CACert certificate for your ZNC.