146 lines
4.6 KiB
Groff
146 lines
4.6 KiB
Groff
.\" Copyright (c) 1985 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)ftpd.8c 6.4 (Berkeley) 5/28/86
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.\"
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.TH FTPD 8
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.SH NAME
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ftpd, in.ftpd, setup.anonftp \- DARPA Internet File Transfer Protocol server
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.SH SYNOPSIS
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.B "ftp stream tcp nowait root /usr/sbin/in.ftpd in.ftpd"
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.br
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.B "tcpd ftp /usr/sbin/in.ftpd"
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.SH DESCRIPTION
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.B Ftpd
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is the DARPA Internet File Transfer Prototocol
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server process. The server uses the TCP protocol
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and listens at the port specified in the ``ftp''
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service specification; see
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.BR services (5).
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.PP
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The ftp server currently supports the following ftp
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requests; case is not distinguished.
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.PP
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.nf
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.ta \w'Request 'u
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\fBRequest Description\fP
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ABOR abort previous command
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ACCT specify account (ignored)
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ALLO allocate storage (vacuously)
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APPE append to a file
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CDUP change to parent of current working directory
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CWD change working directory
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DELE delete a file
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HELP give help information
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LIST give list files in a directory (``ls -lA'')
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MKD make a directory
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MODE specify data transfer \fImode\fP
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NLST give name list of files in directory (``ls'')
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NOOP do nothing
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PASS specify password
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PASV prepare for server-to-server transfer
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PORT specify data connection port
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PWD print the current working directory
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QUIT terminate session
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RETR retrieve a file
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RMD remove a directory
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RNFR specify rename-from file name
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RNTO specify rename-to file name
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STOR store a file
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STOU store a file with a unique name
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STRU specify data transfer \fIstructure\fP
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TYPE specify data transfer \fItype\fP
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USER specify user name
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XCUP change to parent of current working directory
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XCWD change working directory
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XMKD make a directory
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XPWD print the current working directory
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XRMD remove a directory
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.fi
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.PP
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The remaining ftp requests specified in Internet RFC 959 are
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recognized, but not implemented.
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.PP
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The ftp server will abort an active file transfer only when the
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ABOR command is preceded by a Telnet "Interrupt Process" (IP)
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signal and a Telnet "Synch" signal in the command Telnet stream,
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as described in Internet RFC 959.
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.PP
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.B Ftpd
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interprets file names according to the ``globbing''
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conventions used by
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.BR csh (1).
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This allows users to utilize the metacharacters ``*?[]{}~''.
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.PP
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.B Ftpd
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authenticates users according to three rules.
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.IP 1)
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The user name must be in the password data base,
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.BR /etc/passwd ,
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and not have a null password. In this case a password
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must be provided by the client before any file operations
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may be performed.
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.IP 2)
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The user name must not appear in the file
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.BR /etc/ftpusers .
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.IP 3)
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If the user name is ``anonymous'' or ``ftp'', an
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anonymous ftp account must be present in the password
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file (user ``ftp''). In this case the user is allowed
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to log in by specifying any password (by convention this
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is given as the client host's name).
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.PP
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In the last case,
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.B ftpd
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takes special measures to restrict the client's access privileges.
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The server performs a
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.BR chroot (2)
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command to the home directory of the ``ftp'' user.
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In order that system security is not breached, it is recommended
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that the ``ftp'' subtree be constructed with care; the following
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rules are recommended.
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.IP ~ftp)
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Make the home directory owned by ``ftp'' and unwritable by anyone.
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.IP ~ftp/bin)
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Make this directory owned by the super-user and unwritable by
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anyone. The program
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.BR ls (1)
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must be present to support the list commands. This
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program should have mode 111.
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.IP ~ftp/etc)
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This directory could be created, and could have
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.BR passwd (5)
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and
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.BR group (5)
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databases in it so that
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.B ls
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can show file ownership, but outsiders will grab your password file and
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misuse it to spam you. So don't bother.
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.IP ~ftp/pub)
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Make this directory mode 755 and owned by the super-user. Create
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directories in it owned by users if those users want to manage an
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anonymous ftp directory.
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.IP ~ftp/pub/incoming)
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Optionally create this directory for anonymous uploads. Make it mode
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777. The FTP daemon will create files with mode 266, so remote users
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can write a file, but only local users can do something with it.
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.PP
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The script
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.B setup.anonftp
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can be used to create or check an anonymous FTP tree.
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.SH "SEE ALSO"
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.BR ftp (1).
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.SH BUGS
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The anonymous account is inherently dangerous and should
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avoided when possible.
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.ig \" Minix doesn't have privileged port numbers (yet?)
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.PP
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The server must run as the super-user
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to create sockets with privileged port numbers. It maintains
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an effective user id of the logged in user, reverting to
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the super-user only when binding addresses to sockets. The
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possible security holes have been extensively
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scrutinized, but are possibly incomplete.
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..
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