Difference between revisions of "Very Secure FTP Daemon (Italiano)"

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[[Category:HOWTOs (Italiano)]]
 
[[Category:HOWTOs (Italiano)]]
 
{{i18n|Very Secure FTP Daemon}}
 
{{i18n|Very Secure FTP Daemon}}
 +
{{Translateme}}
  
vsftpd sta per "Very secure ftp daemon" (Demone ftp molto sicuro). E' un piccolo (ed efficente) server ftp di cui potresti avere bisogno.
+
'''vsftpd''' (Very Secure FTP Daemon) is a lightweight, stable and secure FTP server for UNIX-like systems.
  
Può funzionare sia con che senza xinetd, ma verrà descritto solo il metodo senza xinetd.
+
== Installation ==
 +
Vsftpd is included in the official repository. Simply install it with pacman:
 +
# pacman -S vsftpd
  
Prima di tutto, installa il pacchetto necessario con pacman
+
The server can be started by using the script below:
  pacman -S vsftpd
+
  # /etc/rc.d/vsftpd start
  
/etc/vsftpd.conf e' un file di configurazione molto ben documentato, ma queste sono le cose basilar da configurare (per il resto leggi i commenti del file)
+
You can also add vsftpd to your daemon array in {{Filename|/etc/rc.conf}} if you want it to be started automatically at boot.
 +
 
 +
See the xinetd section below for procedures to use vsftpd with xinetd.
 +
 
 +
== Configuration ==
 +
Most of the settings in vsftpd are done by editing the file {{Filename|/etc/vsftpd.conf}}. The file itself is well-documented, so this section only highlights some important changes you may want to modify. For all available options and documentation, one can man vsftpd.conf (5).
 +
 
 +
=== Enabling uploading ===
 +
The {{Codeline|WRITE_ENABLE}} flag must be set to YES in {{Filename|/etc/vsftpd.conf}} in order to allow changes to the filesystem, such as uploading:
 +
write_enable=YES
 +
 
 +
=== Local user logging ===
 +
One must set the line to {{Filename|/etc/vsftpd.conf}} to allow users in {{Filename|/etc/passwd}} to login:
 +
local_enable=YES
 +
 
 +
=== Anonymous logging ===
 +
The line in {{Filename|/etc/vsftpd.conf}} controls whether anonymous users can login:
 +
anonymous_enable=YES # Allow anonymous login
 +
no_anon_password=YES # No password is required for an anonymous login
 +
anon_max_rate=30000  # Maximum transfer rate for an anonymous client in bytes per second
 +
 
 +
=== Chroot jail ===
 +
One can set up a chroot environment which prevents the user from leaving its home directory. To enable this, add the following lines to {{Filename|/etc/vsftpd.conf}}:
 +
chroot_list_enable=YES
 +
chroot_list_file=/etc/vsftpd.chroot_list
 +
The {{Codeline|chroot_list_file}} variable specifies the file which contains users that are jailed.
 +
 
 +
For a more restricted environment, one can specify the line:
 +
chroot_local_user=YES
 +
This will make local users jailed by default. In this case, the file specified by {{Codeline|chroot_list_file}} lists users that are '''not''' in a chroot jail.
 +
 
 +
=== Limiting user login ===
 +
It's possible to prevent users from logging into the FTP server by adding two lines to {{Filename|/etc/vsftpd.conf}}:
 +
userlist_enable=YES
 +
userlist_file=/etc/vsftpd.user_list
 +
{{Codeline|userlist_file}} now specifies the file which lists users that are not able to login.
 +
 
 +
If you only want to allow certain users to login, add the line:
 +
userlist_deny=NO
 +
The file specified by {{Codeline|userlist_file}} will now contain users that are able to login.
 +
 
 +
=== Limiting connections ===
 +
One can limit the data transfer rate, number of clients and connections per IP for local users by adding the information in {{Filename|/etc/vsftpd.conf}}:
 +
local_max_rate=1000000 # Maximum data transfer rate in bytes per second
 +
max_clients=50        # Maximum number of clients that may be connected
 +
max_per_ip=2          # Maximum connections per IP
 +
 
 +
=== Using xinetd ===
 +
If you want to use vsftpd with xinetd, add the following lines to {{Filename|/etc/xinetd.d/vsftpd}}:
 
<pre>
 
<pre>
listen=YES
+
service ftp
anonymous_enable=YES      # Se vuoi che si possa accedere al server in modo anonimo
+
{
local_enable=YES         # Questo permette agli utenti locali di accedere al server ftp
+
        socket_type            = stream
write_enable=YES   # Stai attento ad usare questo con anonymous_enable=YES
+
        wait                    = no
tcp_wrappers=YES   # Usa tcp_wrappers per controllare le connessioni.  
+
        user                    = root
 +
        server                  = /usr/sbin/vsftpd
 +
        log_on_success  += HOST DURATION
 +
        log_on_failure  += HOST
 +
        disable                = no
 +
}
 +
</pre>
 +
 
 +
The option below should be set in {{Filename|/etc/vsftpd.conf}}:
 +
pam_service_name=ftp
 +
 
 +
Finally, add xinetd to your daemons line in {{Filename|/etc/rc.conf}}. You do not need to add vsftpd, as it will be called by xinetd whenever necessary.
 +
 
 +
If you get errors like this while connecting to the server:
 +
500 OOPS: cap_set_proc
 +
You need to add ''capability'' in MODULES= line in {{Filename|/etc/rc.conf}}.
 +
 
 +
While upgrading to version 2.1.0 you might get an error like this when connecting to the server from a client:
 +
500 OOPS: could not bind listening IPv4 socket
 +
In earlier versions it has been enough to leave the following lines commented:
 +
# Use this to use vsftpd in standalone mode, otherwise it runs through (x)inetd
 +
# listen=YES
 +
In this newer version, and maybe future releases, it is necessary however to explicitly configure it to '''not''' run in a standalone mode, like this:
 +
# Use this to use vsftpd in standalone mode, otherwise it runs through (x)inetd
 +
listen=NO
 +
 
 +
=== Using SSL to Secure FTP  ===
 +
 
 +
Generate an SSL Cert, e.g. like that:
 +
# cd /etc/ssl/certs
 +
# openssl req -x509 -nodes -days 7300 -newkey rsa:2048 -keyout /etc/ssl/certs/vsftpd.pem -out /etc/ssl/certs/vsftpd.pem
 +
# chmod 600 /etc/ssl/certs/vsftpd.pem
 +
You will be asked alot of Questions about your Company etc., as your Certificate is not a trusted one it doesn't really matter what you fill in. You will use this for encryption! If you plan to use this in a matter of trust get one from a CA like thawte, verisign etc.
 +
 
 +
edit your configuration {{Filename|/etc/vsftpd.conf}}
 +
<pre>
 +
#this is important
 +
ssl_enable=YES
 +
 
 +
#choose what you like, if you accept anon-connections
 +
# you may want to enable this
 +
# allow_anon_ssl=NO
 +
 
 +
#choose what you like,
 +
# it's a matter of performance i guess
 +
# force_local_data_ssl=NO
 +
 
 +
#choose what you like
 +
force_local_logins_ssl=YES
 +
 
 +
#you should at least enable this if you enable ssl...
 +
ssl_tlsv1=YES
 +
#choose what you like
 +
ssl_sslv2=YES
 +
#choose what you like
 +
ssl_sslv3=YES
 +
#give the correct path to your currently generated *.pem file
 +
rsa_cert_file=/etc/ssl/certs/vsftpd.pem
 +
#the *.pem file contains both the key and cert
 +
rsa_private_key_file=/etc/ssl/certs/vsftpd.pem
 
</pre>
 
</pre>
  
Infine aggiungi vsftpd ai demoni nella riga DAEMON= nell'/etc/rc.conf
+
== Tips and tricks ==
 +
=== PAM with virtual users ===
 +
Using virtual users has the advantage of not requiring a real login account on the system. Keeping the environment in a container is of course a more secure option.
  
Una volta riavviato, potrai accedere al tuo server ftp dal link ftp://localhost, mentre per gli utilizzatori esterni il punto di accesso sarà ftp://tuo_ip (l'ip lo puoi controllare con ifconfig).
+
A virtual users database has to be created by first making a simple text file like this:
 +
user1
 +
password1
 +
user2
 +
password2
 +
Include as many virtual users as you wish according to the structure in the example. Save it as logins.txt; the file name does not have any significance. Next step depends on Berkeley database system, which is included in the core system of Arch. As root create the actual database with the help of the logins.txt file, or what you chose to call it:
 +
# db_load -T -t hash -f logins.txt /etc/vsftpd_login.db
 +
It is recommended to restrict permissions for the now created {{Filename|vsftpd_login.db}} file:
 +
# chmod 600 /etc/vsftpd_login.db
 +
{{Warning|Be aware that stocking passwords in plain text is not safe. Don't forget to remove your temporary file with {{codeline|rm logins.txt}}.}}
 +
PAM should now be set to make use of vsftpd_login.db. To make PAM check for user authentication create a file named ftp in the {{Filename|/etc/pam.d/}} directory with the following information:
 +
auth required pam_userdb.so db=/etc/vsftpd_login crypt=hash
 +
account required pam_userdb.so db=/etc/vsftpd_login crypt=hash
 +
{{Note|We use /etc/vsftpd_login without .db extension in PAM-config!}}
 +
Now it is time to create a home for the virtual users. In the example {{Filename|/srv/ftp}} is decided to host data for virtual users, which also reflects the default directory structure of Arch. First create the general user virtual and make {{Filename|/srv/ftp}} its home:
 +
# useradd -d /srv/ftp virtual
 +
Make virtual the owner:
 +
# chown virtual:virtual /srv/ftp
 +
Configure vsftpd to use the created environment by editing /etc/vsftpd.conf. These are the necessary settings to make vsftpd restrict access to virtual users, by user-name and password, and restrict their access to the specified area {{Filename|/srv/ftp}}:
 +
anonymous_enable=NO
 +
local_enable=YES
 +
chroot_local_user=YES
 +
guest_enable=YES
 +
guest_username=virtual
 +
virtual_use_local_privs=YES
 +
If the xinetd method is used start the service. You should now only be allowed to login by user-name and password according to the made database.
  
Per aggiungere dei file al server, basta metterli nella cartella /home/ftp che viene creata con l'installazione di arch. Se si vuole poter aggiungere i file in tale cartella anche da utente, basta cambiargli proprietario con
+
==== Adding private folders for the virtual users ====
 +
First create directories for users:
 +
# mkdir /srv/ftp/user1
 +
# mkdir /srv/ftp/user2
 +
# chown virtual:virtual /srv/ftp/user?/
  
chown nomeutente:users /home/ftp
+
Then, add the following lines to {{Filename|/etc/vsftpd.conf}}:
 +
local_root=/srv/ftp/$USER
 +
user_sub_token=$USER
  
NOTA per gli utenti fastweb: essendo fastweb una rete chiusa, potranno accedere al tuo server esclusivamente gli utenti interni alla rete fastweb, a meno che non si paghi per ottenere un ip pubblico o non si usi una vpn con hamachi
+
== More resources ==
 +
* [http://vsftpd.beasts.org/ vsftpd official homepage]
 +
* [http://vsftpd.beasts.org/vsftpd_conf.html vsftpd.conf man page]

Revision as of 01:49, 21 September 2011

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Notes: please use the first argument of the template to provide more detailed indications. (Discuss in Talk:Very Secure FTP Daemon (Italiano)#)

vsftpd (Very Secure FTP Daemon) is a lightweight, stable and secure FTP server for UNIX-like systems.

Installation

Vsftpd is included in the official repository. Simply install it with pacman:

# pacman -S vsftpd

The server can be started by using the script below:

# /etc/rc.d/vsftpd start

You can also add vsftpd to your daemon array in Template:Filename if you want it to be started automatically at boot.

See the xinetd section below for procedures to use vsftpd with xinetd.

Configuration

Most of the settings in vsftpd are done by editing the file Template:Filename. The file itself is well-documented, so this section only highlights some important changes you may want to modify. For all available options and documentation, one can man vsftpd.conf (5).

Enabling uploading

The Template:Codeline flag must be set to YES in Template:Filename in order to allow changes to the filesystem, such as uploading:

write_enable=YES

Local user logging

One must set the line to Template:Filename to allow users in Template:Filename to login:

local_enable=YES

Anonymous logging

The line in Template:Filename controls whether anonymous users can login:

anonymous_enable=YES # Allow anonymous login
no_anon_password=YES # No password is required for an anonymous login
anon_max_rate=30000  # Maximum transfer rate for an anonymous client in bytes per second

Chroot jail

One can set up a chroot environment which prevents the user from leaving its home directory. To enable this, add the following lines to Template:Filename:

chroot_list_enable=YES
chroot_list_file=/etc/vsftpd.chroot_list

The Template:Codeline variable specifies the file which contains users that are jailed.

For a more restricted environment, one can specify the line:

chroot_local_user=YES

This will make local users jailed by default. In this case, the file specified by Template:Codeline lists users that are not in a chroot jail.

Limiting user login

It's possible to prevent users from logging into the FTP server by adding two lines to Template:Filename:

userlist_enable=YES
userlist_file=/etc/vsftpd.user_list

Template:Codeline now specifies the file which lists users that are not able to login.

If you only want to allow certain users to login, add the line:

userlist_deny=NO

The file specified by Template:Codeline will now contain users that are able to login.

Limiting connections

One can limit the data transfer rate, number of clients and connections per IP for local users by adding the information in Template:Filename:

local_max_rate=1000000 # Maximum data transfer rate in bytes per second
max_clients=50         # Maximum number of clients that may be connected
max_per_ip=2           # Maximum connections per IP

Using xinetd

If you want to use vsftpd with xinetd, add the following lines to Template:Filename:

service ftp
{
        socket_type             = stream
        wait                    = no
        user                    = root
        server                  = /usr/sbin/vsftpd
        log_on_success  += HOST DURATION
        log_on_failure  += HOST
        disable                 = no
}

The option below should be set in Template:Filename:

pam_service_name=ftp

Finally, add xinetd to your daemons line in Template:Filename. You do not need to add vsftpd, as it will be called by xinetd whenever necessary.

If you get errors like this while connecting to the server:

500 OOPS: cap_set_proc

You need to add capability in MODULES= line in Template:Filename.

While upgrading to version 2.1.0 you might get an error like this when connecting to the server from a client:

500 OOPS: could not bind listening IPv4 socket

In earlier versions it has been enough to leave the following lines commented:

# Use this to use vsftpd in standalone mode, otherwise it runs through (x)inetd
# listen=YES

In this newer version, and maybe future releases, it is necessary however to explicitly configure it to not run in a standalone mode, like this:

# Use this to use vsftpd in standalone mode, otherwise it runs through (x)inetd
listen=NO

Using SSL to Secure FTP

Generate an SSL Cert, e.g. like that:

# cd /etc/ssl/certs
# openssl req -x509 -nodes -days 7300 -newkey rsa:2048 -keyout /etc/ssl/certs/vsftpd.pem -out /etc/ssl/certs/vsftpd.pem
# chmod 600 /etc/ssl/certs/vsftpd.pem

You will be asked alot of Questions about your Company etc., as your Certificate is not a trusted one it doesn't really matter what you fill in. You will use this for encryption! If you plan to use this in a matter of trust get one from a CA like thawte, verisign etc.

edit your configuration Template:Filename

#this is important
ssl_enable=YES

#choose what you like, if you accept anon-connections
# you may want to enable this
# allow_anon_ssl=NO

#choose what you like,
# it's a matter of performance i guess
# force_local_data_ssl=NO

#choose what you like
force_local_logins_ssl=YES

#you should at least enable this if you enable ssl...
ssl_tlsv1=YES
#choose what you like
ssl_sslv2=YES
#choose what you like
ssl_sslv3=YES
#give the correct path to your currently generated *.pem file
rsa_cert_file=/etc/ssl/certs/vsftpd.pem
#the *.pem file contains both the key and cert
rsa_private_key_file=/etc/ssl/certs/vsftpd.pem

Tips and tricks

PAM with virtual users

Using virtual users has the advantage of not requiring a real login account on the system. Keeping the environment in a container is of course a more secure option.

A virtual users database has to be created by first making a simple text file like this:

user1
password1
user2
password2

Include as many virtual users as you wish according to the structure in the example. Save it as logins.txt; the file name does not have any significance. Next step depends on Berkeley database system, which is included in the core system of Arch. As root create the actual database with the help of the logins.txt file, or what you chose to call it:

# db_load -T -t hash -f logins.txt /etc/vsftpd_login.db

It is recommended to restrict permissions for the now created Template:Filename file:

# chmod 600 /etc/vsftpd_login.db
Warning: Be aware that stocking passwords in plain text is not safe. Don't forget to remove your temporary file with Template:Codeline.

PAM should now be set to make use of vsftpd_login.db. To make PAM check for user authentication create a file named ftp in the Template:Filename directory with the following information:

auth required pam_userdb.so db=/etc/vsftpd_login crypt=hash 
account required pam_userdb.so db=/etc/vsftpd_login crypt=hash
Note: We use /etc/vsftpd_login without .db extension in PAM-config!

Now it is time to create a home for the virtual users. In the example Template:Filename is decided to host data for virtual users, which also reflects the default directory structure of Arch. First create the general user virtual and make Template:Filename its home:

# useradd -d /srv/ftp virtual

Make virtual the owner:

# chown virtual:virtual /srv/ftp

Configure vsftpd to use the created environment by editing /etc/vsftpd.conf. These are the necessary settings to make vsftpd restrict access to virtual users, by user-name and password, and restrict their access to the specified area Template:Filename:

anonymous_enable=NO
local_enable=YES
chroot_local_user=YES
guest_enable=YES
guest_username=virtual
virtual_use_local_privs=YES

If the xinetd method is used start the service. You should now only be allowed to login by user-name and password according to the made database.

Adding private folders for the virtual users

First create directories for users:

# mkdir /srv/ftp/user1
# mkdir /srv/ftp/user2
# chown virtual:virtual /srv/ftp/user?/

Then, add the following lines to Template:Filename:

local_root=/srv/ftp/$USER
user_sub_token=$USER

More resources