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docs: convert 'tlscerts' page to rst
Note that links from the first table leading to sections of this document further below were removed for simplicity. Signed-off-by: Pavel Hrdina <phrdina@redhat.com> Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This commit is contained in:
Pavel Hrdina
Peter Krempa
parent
d2978caea7
commit
04deb69bd3
@ -31,7 +31,6 @@ docs_html_in_files = [
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'internals',
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'internals',
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'remote',
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'remote',
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'storage',
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'storage',
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'tlscerts',
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'uri',
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'uri',
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'windows',
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'windows',
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]
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]
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@ -110,6 +109,7 @@ docs_rst_files = [
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'testapi',
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'testapi',
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'testsuites',
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'testsuites',
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'testtck',
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'testtck',
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'tlscerts',
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]
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]
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# list of web targets to build for docs/web rule
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# list of web targets to build for docs/web rule
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@ -1,413 +0,0 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html>
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<html xmlns="http://www.w3.org/1999/xhtml">
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<body>
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<h1>TLS x509 certificate setup</h1>
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<ul id="toc"></ul>
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<h2>
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<a id="Remote_PKI">Public Key Infrastructure set up</a>
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</h2>
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<p>
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If you are unsure how to create TLS certificates, skip to the
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next section.
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</p>
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<table class="top_table">
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<tr>
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<th> Location </th>
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<th> Machine </th>
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<th> Description </th>
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<th> Required fields </th>
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</tr>
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<tr>
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<td>
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<code>/etc/pki/CA/cacert.pem</code>
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</td>
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<td> Installed on the client and server </td>
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<td> CA's certificate (<a href="#Remote_TLS_CA">more info</a>)</td>
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<td> n/a </td>
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</tr>
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<tr>
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<td>
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<code>$HOME/.pki/cacert.pem</code>
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</td>
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<td> Installed on the client </td>
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<td> CA's certificate (<a href="#Remote_TLS_CA">more info</a>)</td>
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<td> n/a </td>
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</tr>
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<tr>
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<td>
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<code>/etc/pki/libvirt/private/serverkey.pem</code>
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</td>
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<td> Installed on the server </td>
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<td> Server's private key (<a href="#Remote_TLS_server_certificates">more info</a>)</td>
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<td> n/a </td>
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</tr>
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<tr>
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<td>
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<code>/etc/pki/libvirt/servercert.pem</code>
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</td>
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<td> Installed on the server </td>
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<td> Server's certificate signed by the CA.
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(<a href="#Remote_TLS_server_certificates">more info</a>) </td>
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<td> CommonName (CN) must be the hostname of the server as it
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is seen by clients. All hostname and IP address variants that might
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be used to reach the server should be listed in Subject Alt Name
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fields.</td>
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</tr>
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<tr>
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<td>
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<code>/etc/pki/libvirt/private/clientkey.pem</code>
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</td>
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<td> Installed on the client </td>
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<td> Client's private key. (<a href="#Remote_TLS_client_certificates">more info</a>) </td>
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<td> n/a </td>
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</tr>
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<tr>
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<td>
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<code>/etc/pki/libvirt/clientcert.pem</code>
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</td>
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<td> Installed on the client </td>
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<td> Client's certificate signed by the CA
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(<a href="#Remote_TLS_client_certificates">more info</a>) </td>
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<td> Distinguished Name (DN) can be checked against an access
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control list (<code>tls_allowed_dn_list</code>).
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</td>
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</tr>
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<tr>
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<td>
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<code>$HOME/.pki/libvirt/clientkey.pem</code>
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</td>
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<td> Installed on the client </td>
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<td> Client's private key. (<a href="#Remote_TLS_client_certificates">more info</a>) </td>
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<td> n/a </td>
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</tr>
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<tr>
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<td>
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<code>$HOME/.pki/libvirt/clientcert.pem</code>
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</td>
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<td> Installed on the client </td>
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<td> Client's certificate signed by the CA
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(<a href="#Remote_TLS_client_certificates">more info</a>) </td>
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<td> Distinguished Name (DN) can be checked against an access
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control list (<code>tls_allowed_dn_list</code>).
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</td>
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</tr>
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</table>
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<p>
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If 'pkipath' is specified in URI, then all the client
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certificates must be found in the path specified, otherwise the
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connection will fail with a fatal error. If 'pkipath' is not
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specified:
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</p>
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<ul>
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<li> For a non-root user, libvirt tries to find the certificates
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in $HOME/.pki/libvirt first. If the required CA certificate cannot
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be found, then the global default location
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(/etc/pki/CA/cacert.pem) will be used.
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Likewise, if either the client certificate
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or the client key cannot be found, then the global default
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locations (/etc/pki/libvirt/clientcert.pem,
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/etc/pki/libvirt/private/clientkey.pem) will be used.
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</li>
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<li> For the root user, the global default locations will always be used.</li>
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</ul>
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<h2>
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<a id="Remote_TLS_background">Background to TLS certificates</a>
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</h2>
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<p>
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Libvirt supports TLS certificates for verifying the identity
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of the server and clients. There are two distinct checks involved:
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</p>
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<ul>
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<li> The client should know that it is connecting to the right
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server. Checking done by client by matching the certificate that
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the server sends to the server's hostname. May be disabled by adding
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<code>?no_verify=1</code> to the
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<a href="uri.html#Remote_URI_parameters">remote URI</a>.
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</li>
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<li> The server should know that only permitted clients are
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connecting. This can be done based on client's IP address, or on
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client's IP address and client's certificate. Checking done by the
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server. May be enabled and disabled in the <a href="remote.html#Remote_libvirtd_configuration">libvirtd.conf file</a>.
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</li>
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</ul>
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<p>
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For full certificate checking you will need to have certificates
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issued by a recognised <a href="https://en.wikipedia.org/wiki/Certificate_authority">Certificate
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Authority (CA)</a> for your server(s) and all clients. To avoid the
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expense of getting certificates from a commercial CA, you can set up
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your own CA and tell your server(s) and clients to trust certificates
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issues by your own CA. Follow the instructions in the next section.
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</p>
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<p>
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Be aware that the <a href="remote.html#Remote_libvirtd_configuration">default
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configuration for libvirtd</a> allows any client to connect provided
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they have a valid certificate issued by the CA for their own IP
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address. You may want to change this to make it less (or more)
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permissive, depending on your needs.
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</p>
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<h2>
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<a id="Remote_TLS_CA">Setting up a Certificate Authority (CA)</a>
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</h2>
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<p>
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You will need the <a href="https://www.gnutls.org/manual/html_node/certtool-Invocation.html">GnuTLS
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certtool program documented here</a>. In Fedora, it is in the
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<code>gnutls-utils</code> package.
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</p>
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<p>
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Create a private key for your CA:
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</p>
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<pre>
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certtool --generate-privkey > cakey.pem
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</pre>
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<p>
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and self-sign it by creating a file with the
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signature details called
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<code>ca.info</code> containing:
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</p>
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<pre>
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cn = <i>Name of your organization</i>
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ca
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cert_signing_key
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</pre>
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<pre>
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certtool --generate-self-signed --load-privkey cakey.pem \
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--template ca.info --outfile cacert.pem
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</pre>
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<p>
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(You can delete <code>ca.info</code> file now if you
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want).
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</p>
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<p>
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Now you have two files which matter:
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</p>
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<ul>
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<li><code>cakey.pem</code> - Your CA's private key (keep this very secret!)
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</li>
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<li><code>cacert.pem</code> - Your CA's certificate (this is public).
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</li>
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</ul>
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<p><code>cacert.pem</code> has to be installed on clients and
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server(s) to let them know that they can trust certificates issued by
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your CA.
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</p>
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<p>
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The normal installation directory for <code>cacert.pem</code>
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is <code>/etc/pki/CA/cacert.pem</code> on all clients and servers.
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</p>
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<p>
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To see the contents of this file, do:
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</p>
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<pre><b>certtool -i --infile cacert.pem</b>
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X.509 certificate info:
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Version: 3
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Serial Number (hex): 00
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Subject: CN=Libvirt Project
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Issuer: CN=Libvirt Project
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Signature Algorithm: RSA-SHA
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Validity:
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Not Before: Mon Jun 18 16:22:18 2007
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Not After: Tue Jun 17 16:22:18 2008
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<i>[etc]</i>
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</pre>
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<p>
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This is all that is required to set up your CA. Keep the CA's private
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key carefully as you will need it when you come to issue certificates
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for your clients and servers.
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</p>
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<h2>
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<a id="Remote_TLS_server_certificates">Issuing server certificates</a>
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</h2>
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<p>
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For each server (libvirtd) you need to issue a certificate
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containing one or more hostnames and/or IP addresses.
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Historically the CommonName (CN) field would contain the
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hostname of the server and would match the hostname used
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in the URI that clients pass to libvirt. In most TLS implementations
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the CN field is considered legacy data. The preferential mechanism
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is to use Subject Alt Name (SAN) extension fields to validate
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against. In the future use of the CN field for validation may be
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discontinued entirely, so it is strongly recommended to
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include the SAN fields.
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</p>
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<p>
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In the example below, clients will be connecting to the
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server using a <a href="uri.html#URI_remote">URI</a> of
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<code>qemu://compute1.libvirt.org/system</code>, so the CN
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must be "<code>compute1.libvirt.org</code>".
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</p>
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<p>
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Make a private key for the server:
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</p>
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<pre>
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certtool --generate-privkey > serverkey.pem
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</pre>
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<p>
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and sign that key with the CA's private key by first
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creating a template file called <code>server.info</code>.
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The template file will contain a number of fields to define
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the server as follows:
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</p>
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<pre>
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organization = <i>Name of your organization</i>
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cn = compute1.libvirt.org
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dns_name = compute1
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dns_name = compute1.libvirt.org
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ip_address = 10.0.0.74
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ip_address = 192.168.1.24
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ip_address = 2001:cafe::74
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ip_address = fe20::24
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tls_www_server
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encryption_key
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signing_key
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</pre>
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<p>
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The 'cn' field should refer to the fully qualified public
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hostname of the server. For the SAN extension data, there
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must also be one or more 'dns_name' fields that contain all
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possible hostnames that can be reasonably used by clients
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to reach the server, both with and without domain name
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qualifiers. If clients are likely to connect to the server
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by IP address, then one or more 'ip_address' fields should
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also be added.
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</p>
|
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<p>
|
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Use the template file as input to a <code>certtool</code>
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|
||||||
command to sign the server certificate:
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|
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</p>
|
|
||||||
<pre>
|
|
||||||
certtool --generate-certificate --load-privkey serverkey.pem \
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|
||||||
--load-ca-certificate cacert.pem --load-ca-privkey cakey.pem \
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|
||||||
--template server.info --outfile servercert.pem
|
|
||||||
</pre>
|
|
||||||
<p>
|
|
||||||
This gives two files:
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|
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</p>
|
|
||||||
<ul>
|
|
||||||
<li><code>serverkey.pem</code> - The server's private key.
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|
||||||
</li>
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||||||
<li><code>servercert.pem</code> - The server's public key.
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|
||||||
</li>
|
|
||||||
</ul>
|
|
||||||
<p>
|
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||||||
We can examine this certificate and its signature:
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|
||||||
</p>
|
|
||||||
<pre><b>certtool -i --infile servercert.pem</b>
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|
||||||
X.509 certificate info:
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|
||||||
|
|
||||||
Version: 3
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|
||||||
Serial Number (hex): 00
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|
||||||
Subject: O=Libvirt Project,CN=compute1.libvirt.org
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|
||||||
Issuer: CN=Libvirt Project
|
|
||||||
Signature Algorithm: RSA-SHA
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|
||||||
Validity:
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|
||||||
Not Before: Wed Oct 04 09:09:44 UTC 2017
|
|
||||||
Not After: Thu Oct 04 09:09:44 UTC 2018
|
|
||||||
Extensions:
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|
||||||
Basic Constraints (critical):
|
|
||||||
Certificate Authority (CA): FALSE
|
|
||||||
Subject Alternative Name (not critical):
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||||||
DNSname: compute1
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|
||||||
DNSname: compute1.libvirt.org
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|
||||||
IPAddress: 10.0.0.74
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|
||||||
IPAddress: 192.168.1.24
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|
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IPAddress: 2001:cafe::74
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|
||||||
IPAddress: fe20::24
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|
||||||
</pre>
|
|
||||||
<p>
|
|
||||||
Note the "Issuer" CN is "Libvirt Project" (the CA) and
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|
||||||
the "Subject" CN is "compute1.libvirt.org" (the server).
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|
||||||
Notice that the hostname listed in the CN must also
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|
||||||
be duplicated as a DNSname entry
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|
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</p>
|
|
||||||
<p>
|
|
||||||
Finally we have two files to install:
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|
||||||
</p>
|
|
||||||
<ul>
|
|
||||||
<li><code>serverkey.pem</code> is
|
|
||||||
the server's private key which should be copied to the
|
|
||||||
server <i>only</i> as
|
|
||||||
<code>/etc/pki/libvirt/private/serverkey.pem</code>.
|
|
||||||
</li>
|
|
||||||
<li><code>servercert.pem</code> is the server's certificate
|
|
||||||
which can be installed on the server as
|
|
||||||
<code>/etc/pki/libvirt/servercert.pem</code>.
|
|
||||||
</li>
|
|
||||||
</ul>
|
|
||||||
<h2>
|
|
||||||
<a id="Remote_TLS_client_certificates">Issuing client certificates</a>
|
|
||||||
</h2>
|
|
||||||
<p>
|
|
||||||
For each client (ie. any program linked with libvirt, such as
|
|
||||||
<a href="https://virt-manager.org/">virt-manager</a>)
|
|
||||||
you need to issue a certificate with the X.509 Distinguished Name (DN)
|
|
||||||
set to a suitable name. You can decide this on a company / organisation
|
|
||||||
policy. For example:
|
|
||||||
</p>
|
|
||||||
<pre>
|
|
||||||
C=GB,ST=London,L=London,O=Libvirt Project,CN=<i>name_of_client</i>
|
|
||||||
</pre>
|
|
||||||
<p>
|
|
||||||
The process is the same as for
|
|
||||||
<a href="#Remote_TLS_server_certificates">setting up the
|
|
||||||
server certificate</a> so here we just briefly cover the
|
|
||||||
steps.
|
|
||||||
</p>
|
|
||||||
<ol>
|
|
||||||
<li>
|
|
||||||
Make a private key:
|
|
||||||
<pre>
|
|
||||||
certtool --generate-privkey > clientkey.pem
|
|
||||||
</pre>
|
|
||||||
</li>
|
|
||||||
<li>
|
|
||||||
Act as CA and sign the certificate. Create client.info containing:
|
|
||||||
<pre>
|
|
||||||
country = GB
|
|
||||||
state = London
|
|
||||||
locality = London
|
|
||||||
organization = Libvirt Project
|
|
||||||
cn = client1
|
|
||||||
tls_www_client
|
|
||||||
encryption_key
|
|
||||||
signing_key
|
|
||||||
</pre>
|
|
||||||
and sign by doing:
|
|
||||||
<pre>
|
|
||||||
certtool --generate-certificate --load-privkey clientkey.pem \
|
|
||||||
--load-ca-certificate cacert.pem --load-ca-privkey cakey.pem \
|
|
||||||
--template client.info --outfile clientcert.pem
|
|
||||||
</pre>
|
|
||||||
</li>
|
|
||||||
<li>
|
|
||||||
Install the certificates on the client machine:
|
|
||||||
<pre>
|
|
||||||
cp clientkey.pem /etc/pki/libvirt/private/clientkey.pem
|
|
||||||
cp clientcert.pem /etc/pki/libvirt/clientcert.pem
|
|
||||||
</pre>
|
|
||||||
</li>
|
|
||||||
</ol>
|
|
||||||
<h2>
|
|
||||||
<a id="Remote_TLS_troubleshooting">Troubleshooting TLS certificate problems</a>
|
|
||||||
</h2>
|
|
||||||
<dl>
|
|
||||||
<dt> failed to verify client's certificate </dt>
|
|
||||||
<dd>
|
|
||||||
<p>
|
|
||||||
On the server side, run the libvirtd server with
|
|
||||||
the '--listen' and '--verbose' options while the
|
|
||||||
client is connecting. The verbose log messages should
|
|
||||||
tell you enough to diagnose the problem.
|
|
||||||
</p>
|
|
||||||
</dd>
|
|
||||||
</dl>
|
|
||||||
<p> You can use the virt-pki-validate shell script
|
|
||||||
to analyze the setup on the client or server machines, preferably as root.
|
|
||||||
It will try to point out the possible problems and provide solutions to
|
|
||||||
fix the set up up to a point where you have secure remote access.</p>
|
|
||||||
</body>
|
|
||||||
</html>
|
|
||||||
331
docs/tlscerts.rst
Normal file
331
docs/tlscerts.rst
Normal file
@ -0,0 +1,331 @@
|
|||||||
|
==========================
|
||||||
|
TLS x509 certificate setup
|
||||||
|
==========================
|
||||||
|
|
||||||
|
.. contents::
|
||||||
|
|
||||||
|
Public Key Infrastructure set up
|
||||||
|
--------------------------------
|
||||||
|
|
||||||
|
If you are unsure how to create TLS certificates, skip to the next section.
|
||||||
|
|
||||||
|
.. list-table::
|
||||||
|
:header-rows: 1
|
||||||
|
|
||||||
|
* - Location
|
||||||
|
- Machine
|
||||||
|
- Description
|
||||||
|
- Required fields
|
||||||
|
|
||||||
|
* - ``/etc/pki/CA/cacert.pem``
|
||||||
|
- Installed on the client and server
|
||||||
|
- CA's certificate
|
||||||
|
- n/a
|
||||||
|
|
||||||
|
* - ``$HOME/.pki/cacert.pem``
|
||||||
|
- Installed on the client
|
||||||
|
- CA's certificate
|
||||||
|
- n/a
|
||||||
|
|
||||||
|
* - ``/etc/pki/libvirt/private/serverkey.pem``
|
||||||
|
- Installed on the server
|
||||||
|
- Server's private key
|
||||||
|
- n/a
|
||||||
|
|
||||||
|
* - ``/etc/pki/libvirt/servercert.pem``
|
||||||
|
- Installed on the server
|
||||||
|
- Server's certificate signed by the CA
|
||||||
|
- CommonName (CN) must be the hostname of the server as it is seen by
|
||||||
|
clients. All hostname and IP address variants that might be used to
|
||||||
|
reach the server should be listed in Subject Alt Name fields.
|
||||||
|
|
||||||
|
* - ``/etc/pki/libvirt/private/clientkey.pem``
|
||||||
|
- Installed on the client
|
||||||
|
- Client's private key
|
||||||
|
- n/a
|
||||||
|
|
||||||
|
* - ``/etc/pki/libvirt/clientcert.pem``
|
||||||
|
- Installed on the client
|
||||||
|
- Client's certificate signed by the CA
|
||||||
|
- Distinguished Name (DN) can be checked against an access control list
|
||||||
|
(``tls_allowed_dn_list``).
|
||||||
|
|
||||||
|
* - ``$HOME/.pki/libvirt/clientkey.pem``
|
||||||
|
- Installed on the client
|
||||||
|
- Client's private key
|
||||||
|
- n/a
|
||||||
|
|
||||||
|
* - ``$HOME/.pki/libvirt/clientcert.pem``
|
||||||
|
- Installed on the client
|
||||||
|
- Client's certificate signed by the CA
|
||||||
|
(`more info <#Remote_TLS_client_certificates>`__)
|
||||||
|
- Distinguished Name (DN) can be checked against an access control list
|
||||||
|
(``tls_allowed_dn_list``).
|
||||||
|
|
||||||
|
If 'pkipath' is specified in URI, then all the client certificates must be found
|
||||||
|
in the path specified, otherwise the connection will fail with a fatal error. If
|
||||||
|
'pkipath' is not specified:
|
||||||
|
|
||||||
|
- For a non-root user, libvirt tries to find the certificates in
|
||||||
|
$HOME/.pki/libvirt first. If the required CA certificate cannot be found,
|
||||||
|
then the global default location (/etc/pki/CA/cacert.pem) will be used.
|
||||||
|
Likewise, if either the client certificate or the client key cannot be found,
|
||||||
|
then the global default locations (/etc/pki/libvirt/clientcert.pem,
|
||||||
|
/etc/pki/libvirt/private/clientkey.pem) will be used.
|
||||||
|
|
||||||
|
- For the root user, the global default locations will always be used.
|
||||||
|
|
||||||
|
Background to TLS certificates
|
||||||
|
------------------------------
|
||||||
|
|
||||||
|
Libvirt supports TLS certificates for verifying the identity of the server and
|
||||||
|
clients. There are two distinct checks involved:
|
||||||
|
|
||||||
|
- The client should know that it is connecting to the right server. Checking
|
||||||
|
done by client by matching the certificate that the server sends to the
|
||||||
|
server's hostname. May be disabled by adding ``?no_verify=1`` to the `remote
|
||||||
|
URI <uri.html#Remote_URI_parameters>`__.
|
||||||
|
|
||||||
|
- The server should know that only permitted clients are connecting. This can
|
||||||
|
be done based on client's IP address, or on client's IP address and client's
|
||||||
|
certificate. Checking done by the server. May be enabled and disabled in the
|
||||||
|
`libvirtd.conf file <remote.html#Remote_libvirtd_configuration>`__.
|
||||||
|
|
||||||
|
For full certificate checking you will need to have certificates issued by a
|
||||||
|
recognised `Certificate Authority
|
||||||
|
(CA) <https://en.wikipedia.org/wiki/Certificate_authority>`__ for your server(s)
|
||||||
|
and all clients. To avoid the expense of getting certificates from a commercial
|
||||||
|
CA, you can set up your own CA and tell your server(s) and clients to trust
|
||||||
|
certificates issues by your own CA. Follow the instructions in the next section.
|
||||||
|
|
||||||
|
Be aware that the `default configuration for
|
||||||
|
libvirtd <remote.html#Remote_libvirtd_configuration>`__ allows any client to
|
||||||
|
connect provided they have a valid certificate issued by the CA for their own IP
|
||||||
|
address. You may want to change this to make it less (or more) permissive,
|
||||||
|
depending on your needs.
|
||||||
|
|
||||||
|
Setting up a Certificate Authority (CA)
|
||||||
|
---------------------------------------
|
||||||
|
|
||||||
|
You will need the `GnuTLS certtool program documented
|
||||||
|
here <https://www.gnutls.org/manual/html_node/certtool-Invocation.html>`__. In
|
||||||
|
Fedora, it is in the ``gnutls-utils`` package.
|
||||||
|
|
||||||
|
Create a private key for your CA:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-privkey > cakey.pem
|
||||||
|
|
||||||
|
and self-sign it by creating a file with the signature details called
|
||||||
|
``ca.info`` containing:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
cn = Name of your organization
|
||||||
|
ca
|
||||||
|
cert_signing_key
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-self-signed --load-privkey cakey.pem \
|
||||||
|
--template ca.info --outfile cacert.pem
|
||||||
|
|
||||||
|
(You can delete ``ca.info`` file now if you want).
|
||||||
|
|
||||||
|
Now you have two files which matter:
|
||||||
|
|
||||||
|
- ``cakey.pem`` - Your CA's private key (keep this very secret!)
|
||||||
|
|
||||||
|
- ``cacert.pem`` - Your CA's certificate (this is public).
|
||||||
|
|
||||||
|
``cacert.pem`` has to be installed on clients and server(s) to let them know
|
||||||
|
that they can trust certificates issued by your CA.
|
||||||
|
|
||||||
|
The normal installation directory for ``cacert.pem`` is
|
||||||
|
``/etc/pki/CA/cacert.pem`` on all clients and servers.
|
||||||
|
|
||||||
|
To see the contents of this file, do:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool -i --infile cacert.pem
|
||||||
|
|
||||||
|
X.509 certificate info:
|
||||||
|
|
||||||
|
Version: 3
|
||||||
|
Serial Number (hex): 00
|
||||||
|
Subject: CN=Libvirt Project
|
||||||
|
Issuer: CN=Libvirt Project
|
||||||
|
Signature Algorithm: RSA-SHA
|
||||||
|
Validity:
|
||||||
|
Not Before: Mon Jun 18 16:22:18 2007
|
||||||
|
Not After: Tue Jun 17 16:22:18 2008
|
||||||
|
[etc]
|
||||||
|
|
||||||
|
This is all that is required to set up your CA. Keep the CA's private key
|
||||||
|
carefully as you will need it when you come to issue certificates for your
|
||||||
|
clients and servers.
|
||||||
|
|
||||||
|
Issuing server certificates
|
||||||
|
---------------------------
|
||||||
|
|
||||||
|
For each server (libvirtd) you need to issue a certificate containing one or
|
||||||
|
more hostnames and/or IP addresses. Historically the CommonName (CN) field would
|
||||||
|
contain the hostname of the server and would match the hostname used in the URI
|
||||||
|
that clients pass to libvirt. In most TLS implementations the CN field is
|
||||||
|
considered legacy data. The preferential mechanism is to use Subject Alt Name
|
||||||
|
(SAN) extension fields to validate against. In the future use of the CN field
|
||||||
|
for validation may be discontinued entirely, so it is strongly recommended to
|
||||||
|
include the SAN fields.
|
||||||
|
|
||||||
|
In the example below, clients will be connecting to the server using a
|
||||||
|
`URI <uri.html#URI_remote>`__ of ``qemu://compute1.libvirt.org/system``, so the
|
||||||
|
CN must be "``compute1.libvirt.org``".
|
||||||
|
|
||||||
|
Make a private key for the server:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-privkey > serverkey.pem
|
||||||
|
|
||||||
|
and sign that key with the CA's private key by first creating a template file
|
||||||
|
called ``server.info``. The template file will contain a number of fields to
|
||||||
|
define the server as follows:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
organization = Name of your organization
|
||||||
|
cn = compute1.libvirt.org
|
||||||
|
dns_name = compute1
|
||||||
|
dns_name = compute1.libvirt.org
|
||||||
|
ip_address = 10.0.0.74
|
||||||
|
ip_address = 192.168.1.24
|
||||||
|
ip_address = 2001:cafe::74
|
||||||
|
ip_address = fe20::24
|
||||||
|
tls_www_server
|
||||||
|
encryption_key
|
||||||
|
signing_key
|
||||||
|
|
||||||
|
The 'cn' field should refer to the fully qualified public hostname of the
|
||||||
|
server. For the SAN extension data, there must also be one or more 'dns_name'
|
||||||
|
fields that contain all possible hostnames that can be reasonably used by
|
||||||
|
clients to reach the server, both with and without domain name qualifiers. If
|
||||||
|
clients are likely to connect to the server by IP address, then one or more
|
||||||
|
'ip_address' fields should also be added.
|
||||||
|
|
||||||
|
Use the template file as input to a ``certtool`` command to sign the server
|
||||||
|
certificate:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-certificate --load-privkey serverkey.pem \
|
||||||
|
--load-ca-certificate cacert.pem --load-ca-privkey cakey.pem \
|
||||||
|
--template server.info --outfile servercert.pem
|
||||||
|
|
||||||
|
This gives two files:
|
||||||
|
|
||||||
|
- ``serverkey.pem`` - The server's private key.
|
||||||
|
|
||||||
|
- ``servercert.pem`` - The server's public key.
|
||||||
|
|
||||||
|
We can examine this certificate and its signature:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool -i --infile servercert.pem
|
||||||
|
X.509 certificate info:
|
||||||
|
|
||||||
|
Version: 3
|
||||||
|
Serial Number (hex): 00
|
||||||
|
Subject: O=Libvirt Project,CN=compute1.libvirt.org
|
||||||
|
Issuer: CN=Libvirt Project
|
||||||
|
Signature Algorithm: RSA-SHA
|
||||||
|
Validity:
|
||||||
|
Not Before: Wed Oct 04 09:09:44 UTC 2017
|
||||||
|
Not After: Thu Oct 04 09:09:44 UTC 2018
|
||||||
|
Extensions:
|
||||||
|
Basic Constraints (critical):
|
||||||
|
Certificate Authority (CA): FALSE
|
||||||
|
Subject Alternative Name (not critical):
|
||||||
|
DNSname: compute1
|
||||||
|
DNSname: compute1.libvirt.org
|
||||||
|
IPAddress: 10.0.0.74
|
||||||
|
IPAddress: 192.168.1.24
|
||||||
|
IPAddress: 2001:cafe::74
|
||||||
|
IPAddress: fe20::24
|
||||||
|
|
||||||
|
Note the "Issuer" CN is "Libvirt Project" (the CA) and the "Subject" CN is
|
||||||
|
"compute1.libvirt.org" (the server). Notice that the hostname listed in the CN
|
||||||
|
must also be duplicated as a DNSname entry
|
||||||
|
|
||||||
|
Finally we have two files to install:
|
||||||
|
|
||||||
|
- ``serverkey.pem`` is the server's private key which should be copied to the
|
||||||
|
server *only* as ``/etc/pki/libvirt/private/serverkey.pem``.
|
||||||
|
|
||||||
|
- ``servercert.pem`` is the server's certificate which can be installed on the
|
||||||
|
server as ``/etc/pki/libvirt/servercert.pem``.
|
||||||
|
|
||||||
|
Issuing client certificates
|
||||||
|
---------------------------
|
||||||
|
|
||||||
|
For each client (ie. any program linked with libvirt, such as
|
||||||
|
`virt-manager <https://virt-manager.org/>`__) you need to issue a certificate
|
||||||
|
with the X.509 Distinguished Name (DN) set to a suitable name. You can decide
|
||||||
|
this on a company / organisation policy. For example:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
C=GB,ST=London,L=London,O=Libvirt Project,CN=name_of_client
|
||||||
|
|
||||||
|
The process is the same as for `setting up the server
|
||||||
|
certificate <#Remote_TLS_server_certificates>`__ so here we just briefly cover
|
||||||
|
the steps.
|
||||||
|
|
||||||
|
#. Make a private key:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-privkey > clientkey.pem
|
||||||
|
|
||||||
|
#. Act as CA and sign the certificate. Create client.info containing:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
country = GB
|
||||||
|
state = London
|
||||||
|
locality = London
|
||||||
|
organization = Libvirt Project
|
||||||
|
cn = client1
|
||||||
|
tls_www_client
|
||||||
|
encryption_key
|
||||||
|
signing_key
|
||||||
|
|
||||||
|
and sign by doing:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
certtool --generate-certificate --load-privkey clientkey.pem \
|
||||||
|
--load-ca-certificate cacert.pem --load-ca-privkey cakey.pem \
|
||||||
|
--template client.info --outfile clientcert.pem
|
||||||
|
|
||||||
|
#. Install the certificates on the client machine:
|
||||||
|
|
||||||
|
::
|
||||||
|
|
||||||
|
cp clientkey.pem /etc/pki/libvirt/private/clientkey.pem
|
||||||
|
cp clientcert.pem /etc/pki/libvirt/clientcert.pem
|
||||||
|
|
||||||
|
Troubleshooting TLS certificate problems
|
||||||
|
----------------------------------------
|
||||||
|
|
||||||
|
failed to verify client's certificate
|
||||||
|
On the server side, run the libvirtd server with the '--listen' and
|
||||||
|
'--verbose' options while the client is connecting. The verbose log messages
|
||||||
|
should tell you enough to diagnose the problem.
|
||||||
|
|
||||||
|
You can use the virt-pki-validate shell script to analyze the setup on the
|
||||||
|
client or server machines, preferably as root. It will try to point out the
|
||||||
|
possible problems and provide solutions to fix the set up up to a point where
|
||||||
|
you have secure remote access.
|
||||||
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Reference in New Issue
Block a user