1.\" $NetBSD: ftpd.8,v 1.7 1995/04/11 02:44:53 cgd Exp $ 2.\" 3.\" Copyright (c) 1985, 1988, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)ftpd.8 8.2 (Berkeley) 4/19/94 35.\" 36.Dd April 19, 1997 37.Dt FTPD 8 38.Os BSD 4.2 39.Sh NAME 40.Nm ftpd 41.Nd Internet File Transfer Protocol server 42.Sh SYNOPSIS 43.Nm 44.Op Fl a Ar authmode 45.Op Fl dilv 46.Op Fl g Ar umask 47.Op Fl p Ar port 48.Op Fl T Ar maxtimeout 49.Op Fl t Ar timeout 50.Op Fl u Ar default umask 51.Op Fl B | Fl -builtin-ls 52.Op Fl -good-chars= Ns Ar string 53.Sh DESCRIPTION 54.Nm Ftpd 55is the 56Internet File Transfer Protocol 57server process. The server uses the 58.Tn TCP 59protocol 60and listens at the port specified in the 61.Dq ftp 62service specification; see 63.Xr services 5 . 64.Pp 65Available options: 66.Bl -tag -width Ds 67.It Fl a 68Select the level of authentication required. Kerberised login can not 69be turned off. The default is to only allow kerberised login. Other 70possibilities can be turned on by giving a string of comma separated 71flags as argument to 72.Fl a . 73Recognised flags are: 74.Bl -tag -width plain 75.It Ar plain 76Allow logging in with plaintext password. The password can be a(n) OTP 77or an ordinary password. 78.It Ar otp 79Same as 80.Ar plain , 81but only OTP is allowed. 82.It Ar ftp 83Allow anonymous login. 84.El 85.Pp 86The following combination modes exists for backwards compatibility: 87.Bl -tag -width plain 88.It Ar none 89Same as 90.Ar plain,ftp . 91.It Ar safe 92Same as 93.Ar ftp . 94.It Ar user 95Ignored. 96.El 97.It Fl d 98Debugging information is written to the syslog using LOG_FTP. 99.It Fl g 100Anonymous users will get a umask of 101.Ar umask . 102.It Fl i 103Open a socket and wait for a connection. This is mainly used for 104debugging when ftpd isn't started by inetd. 105.It Fl l 106Each successful and failed 107.Xr ftp 1 108session is logged using syslog with a facility of LOG_FTP. 109If this option is specified twice, the retrieve (get), store (put), append, 110delete, make directory, remove directory and rename operations and 111their filename arguments are also logged. 112.It Fl p 113Use 114.Ar port 115(a service name or number) instead of the default 116.Ar ftp/tcp . 117.It Fl T 118A client may also request a different timeout period; 119the maximum period allowed may be set to 120.Ar timeout 121seconds with the 122.Fl T 123option. 124The default limit is 2 hours. 125.It Fl t 126The inactivity timeout period is set to 127.Ar timeout 128seconds (the default is 15 minutes). 129.It Fl u 130Set the initial umask to something else than the default 027. 131.It Fl v 132Verbose mode. 133.It Xo 134.Fl B Ns , 135.Fl -builtin-ls 136.Xc 137use built-in ls to list files 138.It Xo 139.Fl -good-chars= Ns Ar string 140.Xc 141allowed anonymous upload filename chars 142.El 143.Pp 144The file 145.Pa /etc/nologin 146can be used to disable ftp access. 147If the file exists, 148.Nm 149displays it and exits. 150If the file 151.Pa /etc/ftpwelcome 152exists, 153.Nm 154prints it before issuing the 155.Dq ready 156message. 157If the file 158.Pa /etc/motd 159exists, 160.Nm 161prints it after a successful login. 162.Pp 163The ftp server currently supports the following ftp requests. 164The case of the requests is ignored. 165.Bl -column "Request" -offset indent 166.It Request Ta "Description" 167.It ABOR Ta "abort previous command" 168.It ACCT Ta "specify account (ignored)" 169.It ALLO Ta "allocate storage (vacuously)" 170.It APPE Ta "append to a file" 171.It CDUP Ta "change to parent of current working directory" 172.It CWD Ta "change working directory" 173.It DELE Ta "delete a file" 174.It HELP Ta "give help information" 175.It LIST Ta "give list files in a directory" Pq Dq Li "ls -lgA" 176.It MKD Ta "make a directory" 177.It MDTM Ta "show last modification time of file" 178.It MODE Ta "specify data transfer" Em mode 179.It NLST Ta "give name list of files in directory" 180.It NOOP Ta "do nothing" 181.It PASS Ta "specify password" 182.It PASV Ta "prepare for server-to-server transfer" 183.It PORT Ta "specify data connection port" 184.It PWD Ta "print the current working directory" 185.It QUIT Ta "terminate session" 186.It REST Ta "restart incomplete transfer" 187.It RETR Ta "retrieve a file" 188.It RMD Ta "remove a directory" 189.It RNFR Ta "specify rename-from file name" 190.It RNTO Ta "specify rename-to file name" 191.It SITE Ta "non-standard commands (see next section)" 192.It SIZE Ta "return size of file" 193.It STAT Ta "return status of server" 194.It STOR Ta "store a file" 195.It STOU Ta "store a file with a unique name" 196.It STRU Ta "specify data transfer" Em structure 197.It SYST Ta "show operating system type of server system" 198.It TYPE Ta "specify data transfer" Em type 199.It USER Ta "specify user name" 200.It XCUP Ta "change to parent of current working directory (deprecated)" 201.It XCWD Ta "change working directory (deprecated)" 202.It XMKD Ta "make a directory (deprecated)" 203.It XPWD Ta "print the current working directory (deprecated)" 204.It XRMD Ta "remove a directory (deprecated)" 205.El 206.Pp 207The following commands are specified by RFC2228. 208.Bl -column Request -offset indent 209.It AUTH Ta "authentication/security mechanism" 210.It ADAT Ta "authentication/security data" 211.It PROT Ta "data channel protection level" 212.It PBSZ Ta "protection buffer size" 213.It MIC Ta "integrity protected command" 214.It CONF Ta "confidentiality protected command" 215.It ENC Ta "privacy protected command" 216.It CCC Ta "clear command channel" 217.El 218.Pp 219The following non-standard or 220.Tn UNIX 221specific commands are supported 222by the 223SITE request. 224.Pp 225.Bl -column Request -offset indent 226.It UMASK Ta change umask, (e.g. 227.Ic "SITE UMASK 002" ) 228.It IDLE Ta set idle-timer, (e.g. 229.Ic "SITE IDLE 60" ) 230.It CHMOD Ta change mode of a file (e.g. 231.Ic "SITE CHMOD 755 filename" ) 232.It FIND Ta quickly find a specific file with GNU 233.Xr locate 1 . 234.It HELP Ta give help information. 235.El 236.Pp 237The following Kerberos related site commands are understood. 238.Bl -column Request -offset indent 239.It KAUTH Ta obtain remote tickets. 240.It KLIST Ta show remote tickets 241.El 242.Pp 243The remaining ftp requests specified in Internet RFC 959 244are 245recognized, but not implemented. 246MDTM and SIZE are not specified in RFC 959, but will appear in the 247next updated FTP RFC. 248.Pp 249The ftp server will abort an active file transfer only when the 250ABOR 251command is preceded by a Telnet "Interrupt Process" (IP) 252signal and a Telnet "Synch" signal in the command Telnet stream, 253as described in Internet RFC 959. 254If a 255STAT 256command is received during a data transfer, preceded by a Telnet IP 257and Synch, transfer status will be returned. 258.Pp 259.Nm Ftpd 260interprets file names according to the 261.Dq globbing 262conventions used by 263.Xr csh 1 . 264This allows users to utilize the metacharacters 265.Dq Li \&*?[]{}~ . 266.Pp 267.Nm Ftpd 268authenticates users according to these rules. 269.Pp 270.Bl -enum -offset indent 271.It 272If Kerberos authentication is used, the user must pass valid tickets 273and the principal must be allowed to login as the remote user. 274.It 275The login name must be in the password data base, and not have a null 276password (if kerberos is used the password field is not checked). In 277this case a password must be provided by the client before any file 278operations may be performed. If the user has an OTP key, the response 279from a successful USER command will include an OTP challenge. The 280client may choose to respond with a PASS command giving either a 281standard password or an OTP one-time password. The server will 282automatically determine which type of password it has been given and 283attempt to authenticate accordingly. See 284.Xr otp 1 285for more information on OTP authentication. 286.It 287The login name must not appear in the file 288.Pa /etc/ftpusers . 289.It 290The user must have a standard shell returned by 291.Xr getusershell 3 . 292.It 293If the user name appears in the file 294.Pa /etc/ftpchroot 295the session's root will be changed to the user's login directory by 296.Xr chroot 2 297as for an 298.Dq anonymous 299or 300.Dq ftp 301account (see next item). However, the user must still supply a password. 302This feature is intended as a compromise between a fully anonymous account 303and a fully privileged account. The account should also be set up as for an 304anonymous account. 305.It 306If the user name is 307.Dq anonymous 308or 309.Dq ftp , 310an 311anonymous ftp account must be present in the password 312file (user 313.Dq ftp ) . 314In this case the user is allowed 315to log in by specifying any password (by convention an email address for 316the user should be used as the password). 317.El 318.Pp 319In the last case, 320.Nm ftpd 321takes special measures to restrict the client's access privileges. 322The server performs a 323.Xr chroot 2 324to the home directory of the 325.Dq ftp 326user. 327In order that system security is not breached, it is recommended 328that the 329.Dq ftp 330subtree be constructed with care, consider following these guidelines 331for anonymous ftp. 332.Pp 333In general all files should be owned by 334.Dq root , 335and have non-write permissions (644 or 755 depending on the kind of 336file). No files should be owned or writable by 337.Dq ftp 338(possibly with exception for the 339.Pa ~ftp/incoming , 340as specified below). 341.Bl -tag -width "~ftp/pub" -offset indent 342.It Pa ~ftp 343The 344.Dq ftp 345homedirectory should be owned by root. 346.It Pa ~ftp/bin 347The directory for external programs (such as 348.Xr ls 1 ) . 349These programs must either be statically linked, or you must setup an 350environment for dynamic linking when running chrooted. 351These programs will be used if present: 352.Bl -tag -width "locate" -offset indent 353.It ls 354Used when listing files. 355.It compress 356When retrieving a filename that ends in 357.Pa .Z , 358and that file isn't present, 359.Nm 360will try to find the filename without 361.Pa .Z 362and compress it on the fly. 363.It gzip 364Same as compress, just with files ending in 365.Pa .gz . 366.It gtar 367Enables retrieval of whole directories as files ending in 368.Pa .tar . 369Can also be combined with compression. You must use GNU Tar (or some 370other that supports the 371.Fl z 372and 373.Fl Z 374flags). 375.It locate 376Will enable ``fast find'' with the 377.Ic SITE FIND 378command. You must also create a 379.Pa locatedb 380file in 381.Pa ~ftp/etc . 382.El 383.It Pa ~ftp/etc 384If you put copies of the 385.Xr passwd 5 386and 387.Xr group 5 388files here, ls will be able to produce owner names rather than 389numbers. Remember to remove any passwords from these files. 390.Pp 391The file 392.Pa motd , 393if present, will be printed after a successful login. 394.It Pa ~ftp/dev 395Put a copy of 396.Xr /dev/null 7 397here. 398.It Pa ~ftp/pub 399Traditional place to put whatever you want to make public. 400.El 401.Pp 402If you want guests to be able to upload files, create a 403.Pa ~ftp/incoming 404directory owned by 405.Dq root , 406and group 407.Dq ftp 408with mode 730 (make sure 409.Dq ftp 410is member of group 411.Dq ftp ) . 412The following restrictions apply to anonymous users: 413.Bl -bullet 414.It 415Directories created will have mode 700. 416.It 417Uploaded files will be created with an umask of 777, if not changed 418with the 419.Fl g 420option. 421.It 422These command are not accessible: 423.Ic DELE , RMD , RNTO , RNFR , 424.Ic SITE UMASK , 425and 426.Ic SITE CHMOD . 427.It 428Filenames must start with an alpha-numeric character, and consist of 429alpha-numeric characters or any of the following: 430.Li \&+ 431(plus), 432.Li \&- 433(minus), 434.Li \&= 435(equal), 436.Li \&_ 437(underscore), 438.Li \&. 439(period), and 440.Li \&, 441(comma). 442.El 443.Sh FILES 444.Bl -tag -width /etc/ftpwelcome -compact 445.It Pa /etc/ftpusers 446Access list for users. 447.It Pa /etc/ftpchroot 448List of normal users who should be chroot'd. 449.It Pa /etc/ftpwelcome 450Welcome notice. 451.It Pa /etc/motd 452Welcome notice after login. 453.It Pa /etc/nologin 454Displayed and access refused. 455.It Pa ~/.klogin 456Login access for Kerberos. 457.El 458.Sh SEE ALSO 459.Xr ftp 1 , 460.Xr otp 1 , 461.Xr getusershell 3 , 462.Xr ftpusers 5 , 463.Xr syslogd 8 , 464.Sh STANDARDS 465.Bl -tag -compact -width "RFC 1938" 466.It Cm RFC 959 467FTP PROTOCOL SPECIFICATION 468.It Cm RFC 1938 469OTP Specification 470.It Cm RFC 2228 471FTP Security Extensions. 472.El 473.Sh BUGS 474The server must run as the super-user 475to create sockets with privileged port numbers. It maintains 476an effective user id of the logged in user, reverting to 477the super-user only when binding addresses to sockets. The 478possible security holes have been extensively 479scrutinized, but are possibly incomplete. 480.Sh HISTORY 481The 482.Nm 483command appeared in 484.Bx 4.2 . 485