Configurazione SSL/TLS di ProFtpd

Si ipotizza di avere o certificati SSL già pronti

• Attivare il la configurazione SSL

sed -i -e  "s_^#Include /etc/proftpd/tls.conf_Include /etc/proftpd/tls.conf_"  /etc/proftpd/proftpd.conf

• Modificare la configurazione TLS, inserendo i nomi dei certificati corretti:

cat | sudo tee /etc/proftpd/tls.conf <<EOFile 
#
# Proftpd sample configuration for FTPS connections.
#
# Note that FTPS impose some limitations in NAT traversing.
# See http://www.castaglia.org/proftpd/doc/contrib/ProFTPD-mini-HOWTO-TLS.html
# for more information.
#

<IfModule mod_tls.c>
TLSEngine                               on
TLSLog                                  /var/log/proftpd/tls.log
TLSProtocol                             SSLv23
#
# Server SSL certificate. You can generate a self-signed certificate using 
# a command like:
#
# openssl req -x509 -newkey rsa:1024 \
#          -keyout /etc/ssl/private/proftpd.key -out /etc/ssl/certs/proftpd.crt \
#          -nodes -days 365
#
# The proftpd.key file must be readable by root only. The other file can be
# readable by anyone.
#
# chmod 0600 /etc/ssl/private/proftpd.key 
# chmod 0640 /etc/ssl/private/proftpd.key
# 
TLSRSACertificateFile                   /var/lib/dehydrated/certs/ftp.diesis.priv/fullchain.pem
TLSRSACertificateKeyFile                /var/lib/dehydrated/certs/ftp.diesis.priv/privkey.pem
#
# CA the server trusts...
TLSCACertificateFile                    /var/lib/dehydrated/certs/ftp.diesis.priv/chain.pem
# ...or avoid CA cert and be verbose
#TLSOptions                      NoCertRequest EnableDiags 
# ... or the same with relaxed session use for some clients (e.g. FireFtp)
#TLSOptions                      NoCertRequest EnableDiags NoSessionReuseRequired
#
#
# Per default drop connection if client tries to start a renegotiate
# This is a fix for CVE-2009-3555 but could break some clients.
#
#TLSOptions 							AllowClientRenegotiations
#
# Authenticate clients that want to use FTP over TLS?
#
#TLSVerifyClient                         off
#
# Are clients required to use FTP over TLS when talking to this server?
#
#TLSRequired                             on
#
# Allow SSL/TLS renegotiations when the client requests them, but
# do not force the renegotations.  Some clients do not support
# SSL/TLS renegotiations; when mod_tls forces a renegotiation, these
# clients will close the data connection, or there will be a timeout
# on an idle data connection.
#
#TLSRenegotiate                          required off
</IfModule>
EOFile

• Riavviare proftpd

systemctl restart proftpd 
systemctl status proftpd.service -l

• Provare a connettersi con filezilla

• Se succede che proftpd va al 100% di cpu, provare ad aggiungere la direttiva:

SocketOptions sndbuf 1024 rcvbuf 1024

Riferimenti

https://www.server-world.info/en/note?os=Debian_8&p=ftp&f=7

• 100% CPU load for any TLS secured transfer