vsftpd服务

ftp是互联网中进行文件传输的一种协议，基于C/S模式，FTP默认有两个工作端口（20数据传输，21FTP服务端就收客户端发来的指令和）

安装FTP服务

[root@haha-main-130 ~]# yum -y install vsftpd

配置文件位置及内容

[root@haha-main-130 ~]# cat /etc/vsftpd/vsftpd.conf 
# Example config file /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=YES
#
# 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. The vsftpd.conf(5) man page explains
# the behaviour when these options are disabled.
# 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 blah FTP 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=NO
#
# 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=YES

pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

主要配置项

[root@haha-main-130 ~]# cat /etc/vsftpd/vsftpd.conf | grep -vE '^$|^#'
anonymous_enable=YES #是否允许匿名登录
local_enable=YES #是否允许本地用户登录
write_enable=YES #是否允许写入
local_umask=022 #掩码值
dirmessage_enable=YES #是否允许记录日志
xferlog_enable=YES #是否允许记录日志
connect_from_port_20=YES #允许20端口连接
xferlog_file=/var/log/xferlog #日志记录文件位置
xferlog_std_format=YES 
listen=YES #是否打开本地监听
listen_ipv6=YES #ipv6监听
pam_service_name=vsftpd #守护名称
userlist_enable=YES #允许userlist文件内用户登录
tcp_wrappers=YES

vsftp匿名用户模式

• 任何人不需要账号密码登录

配置文件

1.允许匿名用户登录
	anonymous_enable=YES
2.允许匿名用户上传文件
	anon_upload_enable=YES
3.允许匿名用户写入、创建文件夹
	anon_mkdir_write_enable=YES
4.允许匿名用户修改文件名，删除文件夹操作
	anon_other_witer_enable=YES

vsftp本地用户模式

• 基于linux的本地账号密码进行验证，配置简单，但是存在安全隐患

配置文件

[root@haha-main-130 ~]# cat /etc/vsftpd/vsftpd.conf | grep -Ev '^$|^#'
anonymous_enable=NO #关闭匿名用户验证模式
local_enable=YES
write_enable=YES
local_umask=022 #默认文件权限
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_file=/var/log/xferlog
xferlog_std_format=YES
listen=YES
pam_service_name=vsftpd
userlist_enable=YES
userlist_deny=YES
tcp_wrappers=YES	

此时/etc/vsftpd/ftpuser文件中的用户名不允许登录

vsftp虚拟用户模式

• 单独为FTP工具创建用户数据库，基于口令验证账号密码的信息

1. 安装DB工具，能够转化普通文件为vsftpd识别的数据库文件

yum -y install db4 db4-utils

2. 创建用于验证的数据文件

[root@haha-main-130 vsftpd]# cat db.txt 
name1
111
name2
222

3. 加密文件

[root@haha-main-130 vsftpd]# db_load -T -t hash -f /etc/vsftpd/db.txt /etc/vsftpd/db.db
[root@haha-main-130 vsftpd]# cat db.db 
a      Gߊ????
??Gߊ????e1? эh^?
       эh^222name2[root@haha-main-130 vsftpd]# 

4. 创建虚拟用户登录后默认访问的文件夹路径，与linux中的本地用户创建一个映射关系，防止匿名用户登陆之后创建文件提示用户权限问题

# 创建一个本地用户，指定家目录，禁止登录bash
[root@haha-main-130 vsftpd]# useradd -d /var/ftp/v_ftpfir -s /sbin/nologin v_user

# 修改/var/ftp/v_ftpfir目录属性为600
[root@haha-main-130 ftp]# chmod -Rf 755 v_ftpfir/

# 修改/etc/vsftpd/ftpuser文件，禁止v_user用户登录
[root@haha-main-130 vsftpd]# echo 'v_user' >> /etc/vsftpd/ftpusers

5. 修改PAM文件/etc/pam.d/vsftpd

[root@haha-main-130 vsftpd]# cat /etc/pam.d/vsftpd 
#%PAM-1.0
session    optional     pam_keyinit.so    force revoke
auth       required	pam_listfile.so item=user sense=deny file=/etc/vsftpd/ftpusers onerr=succeed
auth       required	pam_shells.so
auth       include	password-auth
account    include	password-auth
session    required     pam_loginuid.so
session    include	password-auth

# 添加如下两行，db之后的参数为db_load之后的文件路径，不需要添加后缀名
auth required pam_userdb.so db=/etc/vsftpd/db
account required pam_userdb.so db=/etc/vsftpd/db

6. 修改vsftpd主配置文件/etc/vsftpd/vsftpd.conf

[root@haha-main-130 vsftpd]# grep -Ev '^$|^#' vsftpd.conf 
anonymous_enable=NO
local_enable=YES
write_enable=YES
local_umask=022
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_file=/var/log/xferlog
xferlog_std_format=YES
listen=YES
pam_service_name=vsftpd
userlist_enable=YES
userlist_deny=YES
tcp_wrappers=YES
# 添加如下配置
guest_enable=YES # 开启虚拟用户
guest_username=v_user # 指定虚拟用户账号（关联的本地用户）
allow_writeable_chroot=YES # 允许写入数据

7. 针对不同用户设置不同的权限

• name1 允许上床，新建，修改，查看，删除
• name2 只读

# 设置关联权限文件夹
mkdir /etc/vsftpd/v_user_dir

# 创建文件，设置权限
[root@haha-main-130 v_user_dir]# pwd
/etc/vsftpd/v_user_dir
[root@haha-main-130 v_user_dir]# cat name1 
anon_upload_enable=YES
anon_mkdir_write_enable=YES
anon_other_write_enable=YES
[root@haha-main-130 v_user_dir]# cat name2 
anon_upload_enable=NO
anon_mkdir_write_enable=NO
anon_other_write_enable=NO
[root@haha-main-130 v_user_dir]# 

# 编辑vsftpd主配置文件，添加如下配置
[root@haha-main-130 v_user_dir]# echo 'user_config_dir=/etc/vsftpd/v_user_dir' >> /etc/vsftpd/vsftpd.conf

8. 重启服务

systemctl restart vsftpd

问题记录

1. 创建文件失败

   ftp> mkdir data
   550 Create directory operation failed.
   

   解决方法：

   修改/var/ftp/pub文件夹所属用户以及所属用户组

   [root@haha-main-130 ftp]# pwd
   /var/ftp
   [root@haha-main-130 ftp]# chown -Rf ftp.ftp pub/
   [root@haha-main-130 ftp]# ll
   总用量 0
   drwxr-xr-x 2 ftp ftp 6 6月   9 2021 pub