Provided by: sudo-ldap_1.9.5p2-3ubuntu2_amd64 bug

NAME

     sudo_logsrvd — sudo event and I/O log server

SYNOPSIS

     sudo_logsrvd [-hnV] [-f file] [-R percentage]

DESCRIPTION

     sudo_logsrvd is a high-performance log server that accepts event and I/O logs from sudo.  It
     can be used to implement centralized logging of sudo logs.  Event log entries may be logged
     either via syslog(3) or to a file.  I/O Logs created by sudo_logsrvd can be replayed via the
     sudoreplay(8) utility in the same way as logs generated directly by the sudoers plugin.

     The server also supports restarting interrupted log transfers.  To distinguish completed I/O
     logs from incomplete ones, the I/O log timing file is set to be read-only when the log is
     complete.

     Configuration parameters for sudo_logsrvd may be specified in the sudo_logsrvd.conf(5) file.

     The options are as follows:

     -f, --file  Read configuration from file instead of the default, /etc/sudo_logsrvd.conf.

     -h, --help  Display a short help message to the standard output and exit.

     -n, --no-fork
                 Run sudo_logsrvd in the foreground instead of detaching from the terminal and
                 becoming a daemon.

     -R, --random-drop
                 For each message, there is a percentage chance that the server will drop the
                 connection.  This is only intended for debugging the ability of a client to
                 restart a connection.

     -V, --version
                 Print the sudo_logsrvd version and exit.

   Securing server connections
     The I/O log data sent to sudo_logsrvd may contain sensitive information such as passwords
     and should be secured using Transport Layer Security (TLS).  Doing so requires having a
     signed certificate on the server and, if tls_checkpeer is enabled in sudo_logsrvd.conf(5), a
     signed certificate on the client as well.

     The certificates can either be signed by a well-known Certificate Authority (CA), or a
     private CA can be used.  Instructions for creating a private CA are included below in the
     EXAMPLES section.

   Debugging sudo_logsrvd
     sudo_logsrvd supports a flexible debugging framework that is configured via Debug lines in
     the sudo.conf(5) file.

     For more information on configuring sudo.conf(5), please refer to its manual.

FILES

     /etc/sudo.conf            Sudo front end configuration

     /etc/sudo_logsrvd.conf    Sudo log server configuration file

     /var/log/sudo-io          Default I/O log file location

     /run/sudo/sudo_logsrvd.pid
                               Process ID file for sudo_logsrvd

EXAMPLES

   Creating self-signed certificates
     Unless you are using certificates signed by a well-known Certificate Authority (or a local
     enterprise CA), you will need to create your own CA that can sign the certificates used by
     sudo_logsrvd, sudo_sendlog, and the sudoers plugin.  The following steps use the openssl(1)
     command to create keys and certificates.

   Initial setup
     First, we need to create a directory structure to store the files for the CA.  We'll create
     a new directory hierarchy in /etc/ssl/sudo for this purpose.

           # mkdir /etc/ssl/sudo
           # cd /etc/ssl/sudo
           # mkdir certs csr newcerts private
           # chmod 700 private
           # touch index.txt
           # echo 1000 > serial

     The serial and index.txt files are used to keep track of signed certificates.

     Next, we need to make a copy of the openssl.conf file and customize it for our new CA.  The
     path to openssl.cnf is system-dependent but /etc/ssl/openssl.cnf is the most common
     location.  You will need to adjust the example below if it has a different location on your
     system.

           # cp /etc/ssl/openssl.cnf .

     Now edit the openssl.cnf file in the current directory and make sure it contains “ca” and
     “CA_default” sections.  Those sections should include the following settings:

           [ ca ]
           default_ca      = CA_default

           [ CA_default ]
           dir             = /etc/ssl/sudo
           certs           = $dir/certs
           database        = $dir/index.txt
           certificate     = $dir/cacert.pem
           serial          = $dir/serial

     If your openssl.conf file already has a “CA_default” section, you may only need to modify
     the “dir” setting.

   Creating the CA key and certificate
     In order to create and sign our own certificates, we need to create a private key and a
     certificate for the root of the CA.  First, create the private key and protect it with a
     pass phrase:

           # openssl genrsa -aes256 -out private/cakey.pem 4096
           # chmod 400 private/cakey.pem

     Next, generate the root certificate, using appropriate values for the site-specific fields:

           # openssl req -config openssl.cnf -key private/cakey.pem \
               -new -x509 -days 7300 -sha256 -extensions v3_ca \
               -out cacert.pem

           Enter pass phrase for private/cakey.pem:
           You are about to be asked to enter information that will be
           incorporated into your certificate request.
           What you are about to enter is what is called a Distinguished Name
           or a DN.
           There are quite a few fields but you can leave some blank.
           For some fields there will be a default value,
           If you enter '.', the field will be left blank.
           -----
           Country Name (2 letter code) [AU]:US
           State or Province Name (full name) [Some-State]:Colorado
           Locality Name (eg, city) []:
           Organization Name (eg, company) [Internet Widgits Pty Ltd]:sudo
           Organizational Unit Name (eg, section) []:sudo Certificate Authority
           Common Name (e.g., server FQDN or YOUR name) []:sudo Root CA
           Email Address []:

           # chmod 444 cacert.pem

     Finally, verify the root certificate:

           # openssl x509 -noout -text -in cacert.pem

   Creating and signing certificates
     The server and client certificates will be signed by the previously created root CA.
     Usually, the root CA is not used to sign server/client certificates directly.  Instead,
     intermediate certificates are created and signed with the root CA and the intermediate certs
     are used to sign CSRs (Certificate Signing Request).  In this example we'll skip this part
     for simplicity's sake and sign the CSRs with the root CA.

     First, generate the private key without a pass phrase.

           # openssl genrsa -out private/logsrvd_key.pem 2048
           # chmod 400 private/logsrvd_key.pem

     Next, create a certificate signing request (CSR) for the server's certificate.  The
     organization name must match the name given in the root certificate.  The common name should
     be either the server's IP address or a fully qualified domain name.

           # openssl req -config openssl.cnf -key private/logsrvd_key.pem -new \
               -sha256 -out csr/logsrvd_csr.pem

           Enter pass phrase for private/logsrvd_key.pem:
           You are about to be asked to enter information that will be
           incorporated into your certificate request.
           What you are about to enter is what is called a Distinguished Name
           or a DN.
           There are quite a few fields but you can leave some blank.
           For some fields there will be a default value,
           If you enter '.', the field will be left blank.
           -----
           Country Name (2 letter code) [AU]:US
           State or Province Name (full name) [Some-State]:Colorado
           Locality Name (eg, city) []:
           Organization Name (eg, company) [Internet Widgits Pty Ltd]:sudo
           Organizational Unit Name (eg, section) []:sudo log server
           Common Name (e.g., server FQDN or YOUR name) []:logserver.example.com
           Email Address []:

           Please enter the following 'extra' attributes
           to be sent with your certificate request
           A challenge password []:
           An optional company name []:

     Now sign the CSR that was just created:

           # openssl ca -config openssl.cnf -days 375 -notext -md sha256 \
               -in csr/logsrvd_csr.pem -out certs/logsrvd_cert.pem

           Using configuration from openssl.cnf
           Enter pass phrase for ./private/cakey.pem:
           Check that the request matches the signature
           Signature ok
           Certificate Details:
                   Serial Number: 4096 (0x1000)
                   Validity
                       Not Before: Nov 11 14:05:05 2019 GMT
                       Not After : Nov 20 14:05:05 2020 GMT
                   Subject:
                       countryName               = US
                       stateOrProvinceName       = Colorado
                       organizationName          = sudo
                       organizationalUnitName    = sudo log server
                       commonName                = logserve.example.com
                   X509v3 extensions:
                       X509v3 Basic Constraints:
                           CA:FALSE
                       Netscape Comment:
                           OpenSSL Generated Certificate
                       X509v3 Subject Key Identifier:
                           4C:50:F9:D0:BE:1A:4C:B2:AC:90:76:56:C7:9E:16:AE:E6:9E:E5:B5
                       X509v3 Authority Key Identifier:
                           keyid:D7:91:24:16:B1:03:06:65:1A:7A:6E:CF:51:E9:5C:CB:7A:95:3E:0C

           Certificate is to be certified until Nov 20 14:05:05 2020 GMT (375 days)
           Sign the certificate? [y/n]:y

           1 out of 1 certificate requests certified, commit? [y/n]y
           Write out database with 1 new entries
           Data Base Updated

     Finally, verify the new certificate:

           # openssl verify -CAfile cacert.pem certs/logsrvd_cert.pem
           certs/logsrvd_cert.pem: OK

     The /etc/ssl/sudo/certs directory now contains a signed and verified certificate for use
     with sudo_logsrvd.

     To generate a client certificate, repeat the process above using a different file name.

   Configuring sudo_logsrvd to use TLS
     To use TLS for client/server communication, both sudo_logsrvd and the sudoers plugin need to
     be configured to use TLS.  Configuring sudo_logsrvd for TLS requires the following settings,
     assuming the same path names used earlier:

           # If set, secure connections with TLS 1.2 or 1.3.
           tls = true

           # Path to the certificate authority bundle file in PEM format.
           tls_cacert = /etc/ssl/sudo/cacert.pem

           # Path to the server's certificate file in PEM format.
           tls_cert = /etc/ssl/sudo/certs/logsrvd_cert.pem

           # Path to the server's private key file in PEM format.
           tls_key = /etc/ssl/sudo/private/logsrvd_key.pem

     The root CA cert (cacert.pem) must be installed on the system running sudo_logsrvd.  If peer
     authentication is enabled on the client, a copy of cacert.pem must be present on the client
     system too.

SEE ALSO

     sudo.conf(5), sudo_logsrvd.conf(5), sudoers(5), sudo(8), sudo_sendlog(8), sudoreplay(8)

AUTHORS

     Many people have worked on sudo over the years; this version consists of code written
     primarily by:

           Todd C. Miller

     See the CONTRIBUTORS file in the sudo distribution (https://www.sudo.ws/contributors.html)
     for an exhaustive list of people who have contributed to sudo.

BUGS

     If you feel you have found a bug in sudo_logsrvd, please submit a bug report at
     https://bugzilla.sudo.ws/

SUPPORT

     Limited free support is available via the sudo-users mailing list, see
     https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search the archives.

DISCLAIMER

     sudo_logsrvd is provided “AS IS” and any express or implied warranties, including, but not
     limited to, the implied warranties of merchantability and fitness for a particular purpose
     are disclaimed.  See the LICENSE file distributed with sudo or
     https://www.sudo.ws/license.html for complete details.