vsftp 如何控制用户是否允许切换到上级目录 ?

配置VSFTPD在默认的情况下，用户可以用用cd .. 切换到上一级目录，如下

220 Welcome to digi ftp testing server
User (10.20.100.252:(none)): benjamin
331 Please specify the password.
Password:
230 Login successful.
ftp> dir
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jan 08 18:38 alex
drwxr-xr-x    2 0        0            4096 Jan 08 18:37 alfa
drwxr-xr-x    2 0        0            4096 Jan 12 16:28 benjamin
drwxr-xr-x    2 0        0            4096 Jan 08 18:35 caren

226 Directory send OK.
ftp: 827 bytes received in 0.03Seconds 26.68Kbytes/sec.

ftp> cd ..
250 Directory successfully changed.
ftp> dir           //显然，文件夹已经变更。如果在赋予用户写的权利，容易搞乱系统
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jul 10  2009 bin
drwxr-xr-x    4 0        0            1024 Jul 10  2009 boot
drwxr-xr-x   10 0        0            7100 Jan 11 15:11 dev
drwxr-xr-x    4 0        0            4096 Dec 28 14:31 digi
drwxr-xr-x   15 0        0            4096 Jan 12 16:31 digibeijing
226 Directory send OK.
ftp: 1557 bytes received in 0.06Seconds 25.11Kbytes/sec.
ftp>
那么如何控制上述问题

1.[root@localhost vsftpd]# vi /etc/vsftpd/vsftpd.conf //编辑vsftpd.conf文件

*************************

chroot_local_user=YES                                 //加入这3条语句
chroot_list_enable=YES
chroot_list_file=/etc/vsftpd/chroot_list

***************************

2.[root@localhost vsftpd]# service vsftpd restart

3.[root@localhost vsftpd]# vi /etc/vsftpd/chroot_list //新建chroot_list文件

************

alex                                                  //添加4个用户
alfa
caren
hansin
~

4.再用benjamin测试，发现cd ..后，还停留在原来的问价夹

[root@localhost vsftpd]# ftp 10.20.100.252
Connected to 10.20.100.252.
Name (10.20.100.252:root): benjamin
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> dir
227 Entering Passive Mode (10,20,100,252,65,89)
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jan 08 18:38 alex
drwxr-xr-x    2 0        0            4096 Jan 08 18:37 alfa
drwxr-xr-x    2 0        0            4096 Jan 12 16:28 benjamin
drwxr-xr-x    2 0        0            4096 Jan 08 18:35 caren
226 Directory send OK.
ftp> cd ..
250 Directory successfully changed.
ftp> dir
227 Entering Passive Mode (10,20,100,252,44,110)
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jan 08 18:38 alex
drwxr-xr-x    2 0        0            4096 Jan 08 18:37 alfa
drwxr-xr-x    2 0        0            4096 Jan 12 16:28 benjamin
drwxr-xr-x    2 0        0            4096 Jan 08 18:35 caren
226 Directory send OK.
ftp>

5.更换为chroot_list文件中caren ，就可以切换目录。所以，要想有切换功能，需要加入到到chroot_list文件中，才可以

[root@localhost vsftpd]# ftp 10.20.100.252
Name (10.20.100.252:root): caren
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> dir
227 Entering Passive Mode (10,20,100,252,99,176)
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jan 08 18:38 alex
drwxr-xr-x    2 0        0            4096 Jan 08 18:37 alfa
drwxr-xr-x    2 0        0            4096 Jan 12 16:28 benjamin
drwxr-xr-x    2 0        0            4096 Jan 08 18:35 caren
drwxr-xr-x    2 0        0            4096 Jan 08 18:36 caroline
226 Directory send OK.
ftp> cd ..
250 Directory successfully changed.
ftp> dir
227 Entering Passive Mode (10,20,100,252,121,112)
150 Here comes the directory listing.
drwxr-xr-x    2 0        0            4096 Jul 10  2009 bin
drwxr-xr-x    4 0        0            1024 Jul 10  2009 boot
drwxr-xr-x   10 0        0            7100 Jan 11 15:11 dev
drwxr-xr-x    4 0        0            4096 Dec 28 14:31 digi
drwxr-xr-x   15 0        0            4096 Jan 12 16:31 digibeijing
226 Directory send OK.
ftp>