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 '%', %h 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 that sftp-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.
For logging to work,
sftp-server must be able to access
/dev/log. 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>