Linux files permission for FTP

SUSE Product Topics SLES for System Z
1

We have one user created let’s called it “USER_a” which is used to perform FTP command “get” files from other system into a directory, let’s called it “Directory_a”. We need the files permission that transferred into “Directory_a” to be change to “644” in order for the group member and others can read it. I have been told this can be done in vsftpd.conf but I have no experience in doing so. So can someone give me some guidance how to start? Because currently the files permission will be “600” when the “get” command complete.

Thank you

2

Just to be clear, I presume on your Linux system (a Z system, or s390x, or
something) that you are running the ‘ftp’ command to FTP into some other
system and pull (download) files to the local system, since that is what
‘get’ does, as opposed to what ‘put’ does.

I ask for that clarification because you said somebody mentioned
vsftpd.conf may help you, but while not an expert on vsftpd I believe that
is only the FTP service, meaning the server side, so that would probably
only apply for upload/put operations, not get operations.

If correct in the assumptions above, I would next check things like your
umask setting for your user. For example if it is 066 or something like
that then I would expect the resulting files to be as you describe them,
with 0600 permissions. On the other hand, if not then perhaps something
about your 'ftp 'command changes its umask when it starts.

Here are some commands to run; please post the output:

#Get the current umask:
umask

#Create a file outside of the 'ftp' command:
touch touched-file
ls -l touched-file

#Do a test via FTP;  note the indented FTP commands
ftp whatever.server.goes.here[color=blue]
> get whatever-file-here
> bye[/color]
ls -l whatever-file-here

The results there may give us some clues. On the other hand if you are
putting/uploading files (to the server), then none of this matters and we
need to get back to vsftpd.conf or something on that side of things.

–
Good luck.

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3

Hi ab,

Thank you for the quick reply and sorry for not mentioning about the SUSE server. The SUSE server is installed on IBM LinuxOne machine.
It seem to be some misunderstanding on our side. I mentioned in the previous post that we performed “get/download” operation but the truth is we are performing “put/upload” operation.
The other system will use “put/upload” operation into a directory named “Directory_a” in our SUSE server using a user named “USER_a”. We have tested by created a file with permission 644, but after perform the ftp “put”, the permission change to 600.

As per your request to ran a command to check on the umask value, please check as following:

USER_a@SUSE_A:~> umask
0002
USER_a@SUSE_A:~> touch testing_create_file.txt
USER_a@SUSE_A:~> ls -l
-rw-rw-r-- 1 USER_a oinstall 0 Oct 28 12:54 testing_create_file.txt

This is the current vsftpd.conf

[CODE]

Example config file /etc/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.

If you do not change anything here you will have a minimum setup for an

anonymus FTP server.

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.

General Settings

Uncomment this to enable any form of FTP write command.

#write_enable=YES

Activate directory messages - messages given to remote users when they

go into a certain directory.

dirmessage_enable=YES

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

You may fully customise the login banner string:

#ftpd_banner=“Welcome to FOOBAR FTP service.”

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

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

If enabled, all user and group information in

directory listings will be displayed as “ftp”.

#hide_ids=YES

Local FTP user Settings

Uncomment this to allow local users to log in.

#local_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 to put local users in a chroot() jail in their home directory

after login.

#chroot_local_user=YES

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().

#chroot_list_enable=YES

(default follows)

#chroot_list_file=/etc/vsftpd.chroot_list

The maximum data transfer rate permitted, in bytes per second, for

local authenticated users. The default is 0 (unlimited).

#local_max_rate=7200

Anonymus FTP user Settings

Allow anonymous FTP?

anonymous_enable=YES

Anonymous users will only be allowed to download files which are

world readable.

anon_world_readable_only=YES

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.

#anon_upload_enable=YES

Default umask for anonymus users is 077. You may wish to change this to 022,

if your users expect that (022 is used by most other ftpd’s)

anon_umask=002

Uncomment this if you want the anonymous FTP user to be able to create

new directories.

#anon_mkdir_write_enable=YES

Uncomment this to enable anonymus FTP users to perform other write operations

like deletion and renaming.

#anon_other_write_enable=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

The maximum data transfer rate permitted, in bytes per second, for anonymous

authenticated users. The default is 0 (unlimited).

#anon_max_rate=7200

Log Settings

Log to the syslog daemon instead of using an logfile.

syslog_enable=NO

Uncomment this to log all FTP requests and responses.

#log_ftp_protocol=YES

Activate logging of uploads/downloads.

#xferlog_enable=YES

You may override where the log file goes if you like. The default is shown

below.

#vsftpd_log_file=/var/log/vsftpd.log

If you want, you can have your log file in standard ftpd xferlog format.

Note: This disables the normal logging unless you enable dual_log_enable below.

#xferlog_std_format=YES

You may override where the log file goes if you like. The default is shown

below.

#xferlog_file=/var/log/xferlog

Enable this to have booth logfiles. Standard xferlog and vsftpd’s own style log.

#dual_log_enable=YES

Uncomment this to enable session status information in the system process listing.

#setproctitle_enable=YES

Transfer Settings

Make sure PORT transfer connections originate from port 20 (ftp-data).

connect_from_port_20=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

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 turning on ascii_download_enable enables malicious remote parties

to consume your I/O resources, by issuing the command “SIZE /big/file” in

ASCII mode.

These ASCII options are split into upload and download because you may wish

to enable ASCII uploads (to prevent uploaded scripts etc. from breaking),

without the DoS risk of SIZE and ASCII downloads. ASCII mangling should be

on the client anyway…

#ascii_upload_enable=YES
#ascii_download_enable=YES

Set to NO if you want to disallow the PASV method of obtaining a data

connection.

#pasv_enable=NO

PAM setting. Do NOT change this unless you know what you do!

pam_service_name=vsftpd

Set listen=YES if you want vsftpd to run standalone

listen=YES

Set to ssl_enable=YES if you want to enable SSL

ssl_enable=NO

Limit passive ports to this range to assis firewalling

pasv_min_port=30000
pasv_max_port=30100
anon_mkdir_write_enable=NO
anon_root=/srv/ftp
anon_upload_enable=NO
#anon_umask=002
chroot_local_user=NO
ftpd_banner=Welcome message
idle_session_timeout=900
local_enable=YES
log_ftp_protocol=NO
max_clients=10
max_per_ip=3
pasv_enable=YES
ssl_sslv2=NO
ssl_sslv3=NO
ssl_tlsv1=YES
write_enable=YES

#The permissions with which uploaded files are created. Umasks are applied on top of this value. You may wish to change to 0777 if you want uploaded files to be executable.
#Default: 0666

file_open_mode=0666[/CODE]

4

Try uncommenting this local_umask value, restarting your vsftpd service,
and then testing again.

On 12/11/2017 10:04 PM, mohd tarmizi wrote:[color=blue]

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[/color]

–
Good luck.

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show your appreciation and click on the star below.

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5

Hi ab,

Finally it work after done some reading searching all over the net. What we do is change these 4 lines:

  1. anon_upload_enable=YES
  2. anon_mkdir_write_enable=YES
  3. file_open_mode=0644
  4. local_umask=002

Then, restart the vsftpd service and it work as desired.

Hopefully this will help others.

Thank you

6

I am glad to hear it is working, and particularly thank-you for sharing
your results for the reason you mentioned.

–
Good luck.

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show your appreciation and click on the star below.

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forum as I do not use the web interface often.