FTP コマンドの制御

FTP コマンドは以下のように存在する。

http://www.iana.org/assignments/ftp-commands-extensions/ftp-commands-extensions.xhtml
http://ja.wikipedia.org/wiki/FTP%E3%82%B3%E3%83%9E%E3%83%B3%E3%83%89%E3%81%AE%E4%B8%80%E8%A6%A7

実行できるコマンドは、/etc/vsftpd/vsftpd.conf の cmds_allowed で制御可能。

以下はデフォルト状態。

# telnet 127.0.0.1 21
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
220 (vsFTPd 2.2.2)
USER XXXX★ユーザ名
331 Please specify the password.
PASS XXXX★パスワード
230 Login successful.
help
214-The following commands are recognized.
 ABOR ACCT ALLO APPE CDUP CWD  DELE EPRT EPSV FEAT HELP LIST MDTM MKD
 MODE NLST NOOP OPTS PASS PASV PORT PWD  QUIT REIN REST RETR RMD  RNFR
 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
 XPWD XRMD
214 Help OK.
stat
211-FTP server status:
     Connected to 127.0.0.1
     Logged in as test01
     TYPE: ASCII
     No session bandwidth limit
     Session timeout in seconds is 300
     Control connection is plain text
     Data connections will be plain text
     At session startup, client count was 1
     vsFTPd 2.2.2 - secure, fast, stable
211 End of status
pwd
257 "/home/xxxx"
quit
221 Goodbye.
Connection closed by foreign host.
#

/etc/vsftpd/vsftpd.conf を以下に設定変更。

cmds_allowed=HELP,STAT

許可したコマンドは実行できる。

# telnet 127.0.0.1 21
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
220 (vsFTPd 2.2.2)
USER XXXX★ユーザ名
331 Please specify the password.
PASS XXXX★パスワード
230 Login successful.
help
214-The following commands are recognized.
 ABOR ACCT ALLO APPE CDUP CWD  DELE EPRT EPSV FEAT HELP LIST MDTM MKD
 MODE NLST NOOP OPTS PASS PASV PORT PWD  QUIT REIN REST RETR RMD  RNFR
 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
 XPWD XRMD
214 Help OK.
stat
211-FTP server status:
     Connected to 127.0.0.1
     Logged in as test01
     TYPE: ASCII
     No session bandwidth limit
     Session timeout in seconds is 300
     Control connection is plain text
     Data connections will be plain text
     At session startup, client count was 1
     vsFTPd 2.2.2 - secure, fast, stable
211 End of status
pwd
550 Permission denied.
quit
550 Permission denied.