FTPS (comúnmente referido como FTP/SSL) es un nombre usado para abarcar un número de formas en las cuales el software FTP puede realizar transferencias de ficheros seguras. Cada forma conlleva el uso de una capa SSL/TLS debajo del protocolo estándar FTP para cifrar los canales de control y/o datos. No debe confundirse con el protocolo seguro de transferencia de ficheros SFTP, el cual suele ser usado con SSH.
Instalar vfstpd
# Centos yum install vsftpd # Ubuntu / Debian apt-get install vsftpd
Comprobar que el binario de vsftpd server instalado tiene soporte para SSL
ldd /usr/sbin/vsftpd | grep -i ssl libssl.so.10 => /lib64/libssl.so.10 (0x00007f124f64b000)
Crear el certificado SSL + llave privada (/etc/vsftpd/vsftpd.pem)
openssl req -x509 -nodes -days 9999 -newkey rsa:20148 -keyout /etc/vsftpd/vsftpd.pem -out /etc/vsftpd/vsftpd.pem
Creación de usuario local (sin shell) y la carpeta donde se subirán descargarán documentos (/home/USUARIO/files).
useradd USUARIO passwd USUARIO usermod -s /sbin/nologin USUARIO chmod a-w /home/USUARIO/ mkdir /home/USUARIO/files chown USUARIO:USUARIO /home/USUARIO/files
La configuración dada anteriormente ayudará a prevenir este error cuando se tiene la opción “allow_writeable_chroot” activa en vsftpd.
500 OOPS: vsftpd: refusing to run with writable root inside chroot ()
En CentOS puede ser aconsejable desctivar SELinux (/etc/selinux/config) y configurar o desactivar el firewall
# CentOS 7 systemctl disable firewalld systemctl enable vsftpd
Configuración de vsftpd (/etc/vsftpd/vsftpd.conf)
# The default compiled in settings are fairly paranoid. This sample file # loosens things up a bit, to make the ftp daemon more usable. # Please see vsftpd.conf.5 for all compiled in defaults. # # READ THIS: This example file is NOT an exhaustive list of vsftpd options. # Please read the vsftpd.conf.5 manual page to get a full idea of vsftpd's # capabilities. # # Allow anonymous FTP? (Beware - allowed by default if you comment this out). anonymous_enable=NO # # Uncomment this to allow local users to log in. # When SELinux is enforcing check for SE bool ftp_home_dir local_enable=YES # # Uncomment this to enable any form of FTP write command. write_enable=YES # # Default umask for local users is 077. You may wish to change this to 022, # if your users expect that (022 is used by most other ftpd's) local_umask=022 # # Uncomment this to allow the anonymous FTP user to upload files. This only # has an effect if the above global write enable is activated. Also, you will # obviously need to create a directory writable by the FTP user. # When SELinux is enforcing check for SE bool allow_ftpd_anon_write, allow_ftpd_full_access #anon_upload_enable=YES # # Uncomment this if you want the anonymous FTP user to be able to create # new directories. #anon_mkdir_write_enable=YES # # Activate directory messages - messages given to remote users when they # go into a certain directory. dirmessage_enable=YES # # Activate logging of uploads/downloads. xferlog_enable=YES # # Make sure PORT transfer connections originate from port 20 (ftp-data). connect_from_port_20=YES # # If you want, you can arrange for uploaded anonymous files to be owned by # a different user. Note! Using "root" for uploaded files is not # recommended! #chown_uploads=YES #chown_username=whoever # # You may override where the log file goes if you like. The default is shown # below. xferlog_file=/var/log/xferlog # # If you want, you can have your log file in standard ftpd xferlog format. # Note that the default log file location is /var/log/xferlog in this case. xferlog_std_format=YES # # You may change the default value for timing out an idle session. #idle_session_timeout=600 # # You may change the default value for timing out a data connection. #data_connection_timeout=120 # # It is recommended that you define on your system a unique user which the # ftp server can use as a totally isolated and unprivileged user. #nopriv_user=ftpsecure # # Enable this and the server will recognise asynchronous ABOR requests. Not # recommended for security (the code is non-trivial). Not enabling it, # however, may confuse older FTP clients. #async_abor_enable=YES # # By default the server will pretend to allow ASCII mode but in fact ignore # the request. Turn on the below options to have the server actually do ASCII # mangling on files when in ASCII mode. # Beware that on some FTP servers, ASCII support allows a denial of service # attack (DoS) via the command "SIZE /big/file" in ASCII mode. vsftpd # predicted this attack and has always been safe, reporting the size of the # raw file. # ASCII mangling is a horrible feature of the protocol. #ascii_upload_enable=YES #ascii_download_enable=YES # # You may fully customise the login banner string: ftpd_banner=Welcome to Vagrant Basebox SFTP service. # # You may specify a file of disallowed anonymous e-mail addresses. Apparently # useful for combatting certain DoS attacks. #deny_email_enable=YES # (default follows) #banned_email_file=/etc/vsftpd/banned_emails # # You may specify an explicit list of local users to chroot() to their home # directory. If chroot_local_user is YES, then this list becomes a list of # users to NOT chroot(). # (Warning! chroot'ing can be very dangerous. If using chroot, make sure that # the user does not have write access to the top level directory within the # chroot) chroot_local_user=YES #chroot_list_enable=YES # (default follows) #chroot_list_file=/etc/vsftpd/chroot_list # # You may activate the "-R" option to the builtin ls. This is disabled by # default to avoid remote users being able to cause excessive I/O on large # sites. However, some broken FTP clients such as "ncftp" and "mirror" assume # the presence of the "-R" option, so there is a strong case for enabling it. ls_recurse_enable=YES # # When "listen" directive is enabled, vsftpd runs in standalone mode and # listens on IPv4 sockets. This directive cannot be used in conjunction # with the listen_ipv6 directive. listen=YES # # This directive enables listening on IPv6 sockets. By default, listening # on the IPv6 "any" address (::) will accept connections from both IPv6 # and IPv4 clients. It is not necessary to listen on *both* IPv4 and IPv6 # sockets. If you want that (perhaps because you want to listen on specific # addresses) then you must run two copies of vsftpd with two configuration # files. # Make sure, that one of the listen options is commented !! listen_ipv6=NO pam_service_name=vsftpd userlist_enable=YES tcp_wrappers=YES # FTPS ssl_enable=YES allow_anon_ssl=YES force_local_data_ssl=NO force_local_logins_ssl=NO ssl_tlsv1=YES ssl_sslv2=NO ssl_sslv3=NO rsa_cert_file=/etc/vsftpd/vsftpd.pem rsa_private_key_file=/etc/vsftpd/vsftpd.pem require_ssl_reuse=NO ssl_ciphers=HIGH
Con las directivas siguientes permitimos también el acceso FTP normal sin obligar al uso de TLS/SSL.
force_local_data_ssl=NO force_local_logins_ssl=NO
Comprobar los logs del servicio vsftpd server en CentOS 7 (systemd)
journalctl -u vsftpd.service
Solución al problema: warning: can't get client address: Socket operation on non-socket.
# Alguna directiva "listen" debe estar activada o bien el puerto desocupado para su uso. listen=YES
Conectar con el programa coreFTP al servicio FTPS: Connection “Connection AUTH TLS”.