NAME
sftp-server
—
SFTP server subsystem
SYNOPSIS
sftp-server |
[-ehR ]
[-d start_directory]
[-f log_facility]
[-l log_level]
[-P blacklisted_requests]
[-p whitelisted_requests]
[-u umask] |
sftp-server |
-Q protocol_feature |
DESCRIPTION
sftp-server
is a program that speaks the server side of
SFTP protocol to stdout and expects client requests from stdin.
sftp-server
is not intended to be called directly, but
from sshd(8) using the Subsystem
option.
Command-line flags to sftp-server
should
be specified in the Subsystem
declaration. See
sshd_config(5) for more information.
Valid options are:
-d
start_directory- specifies an alternate starting directory for users. The pathname may
contain the following tokens that are expanded at runtime: %% is replaced
by a literal '%', %d is replaced by the home directory of the user being
authenticated, and %u is replaced by the username of that user. The
default is to use the user's home directory. This option is useful in
conjunction with the
sshd_config(5)
ChrootDirectory
option. -e
- Causes
sftp-server
to print logging information to stderr instead of syslog for debugging. -f
log_facility- Specifies the facility code that is used when logging messages from
sftp-server
. The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. The default is AUTH. -h
- Displays
sftp-server
usage information. -l
log_level- Specifies which messages will be logged by
sftp-server
. The possible values are: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. INFO and VERBOSE log transactions thatsftp-server
performs on behalf of the client. DEBUG and DEBUG1 are equivalent. DEBUG2 and DEBUG3 each specify higher levels of debugging output. The default is ERROR. -P
blacklisted_requests- Specify a comma-separated list of SFTP protocol requests that are banned
by the server.
sftp-server
will reply to any blacklisted request with a failure. The-Q
flag can be used to determine the supported request types. If both a blacklist and a whitelist are specified, then the blacklist is applied before the whitelist. -p
whitelisted_requests- Specify a comma-separated list of SFTP protocol requests that are
permitted by the server. All request types that are not on the whitelist
will be logged and replied to with a failure message.
Care must be taken when using this feature to ensure that requests made implicitly by SFTP clients are permitted.
-Q
protocol_feature- Query protocol features supported by
sftp-server
. At present the only feature that may be queried is “requests”, which may be used for black or whitelisting (flags-P
and-p
respectively). -R
- Places this instance of
sftp-server
into a read-only mode. Attempts to open files for writing, as well as other operations that change the state of the filesystem, will be denied. -u
umask- Sets an explicit umask(2) to be applied to newly-created files and directories, instead of the user's default mask.
On some systems, sftp-server
must be able
to access /dev/log for logging to work, and use of
sftp-server
in a chroot configuration therefore
requires that
syslogd(8) establish a logging socket inside the chroot
directory.
SEE ALSO
sftp(1), ssh(1), sshd_config(5), sshd(8)
T. Ylonen and S. Lehtinen, SSH File Transfer Protocol, draft-ietf-secsh-filexfer-02.txt, October 2001, work in progress material.
HISTORY
sftp-server
first appeared in
OpenBSD 2.8.
AUTHORS
Markus Friedl <markus@openbsd.org>