.\"	$NetBSD: bozohttpd.8,v 1.93 2023/06/07 20:22:22 mrg Exp $
.\"
.\"	$eterna: bozohttpd.8,v 1.101 2011/11/18 01:25:11 mrg Exp $
.\"
.\" Copyright (c) 1997-2023 Matthew R. Green
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd Sep 12, 2023
.Dt BOZOHTTPD 8
.Os
.Sh NAME
.Nm bozohttpd
.Nd hyper text transfer protocol version 1.1 daemon
.Sh SYNOPSIS
.Nm
.Op Fl EGHVXdefhnqsu
.Op Fl C Ar suffix cgihandler
.Op Fl I Ar port
.Op Fl L Ar prefix script
.Op Fl M Ar suffix type encoding encoding11
.Op Fl m Ar version
.Op Fl P Ar pidfile
.Op Fl R Ar readme
.Op Fl S Ar version
.Op Fl T Ar type timeout
.Op Fl U Ar username
.Op Fl Z Ar cert privkey
.Op Fl c Ar cgibin
.Op Fl i Ar address
.Op Fl p Ar pubdir
.Op Fl t Ar chrootdir
.Op Fl v Ar virtualroot
.Op Fl x Ar index
.Op Fl z Ar ciphers
.Ar slashdir
.Op Ar myname
.Sh DESCRIPTION
The
.Nm
program reads a
.Em HTTP
request from the standard input, and sends a reply to the standard output.
Besides ~user translation and virtual hosting support (see below), all file
requests are from
.Ar slashdir
directory.
The server uses
.Ar myname
as its name, which defaults to the local hostname, obtained from
.Xr gethostname 3
(but see the
.Fl v
option for virtual hosting.)
.Nm
writes logs to
.Xr syslog 3
using the ftp facility (but see the
.Fl s
option for testing and the
.Fl q
option for supressing this.)
.Nm
is designed to be small, simple and relatively featureless,
hopefully increasing its security.
.Ss OPTIONS
The following options are available:
.Bl -tag -width xxxcgibin
.It Fl b
Enables daemon mode, where
.Nm
detaches from the current terminal, running in the background and
servicing HTTP requests.
.It Fl C Ar suffix cgihandler
Adds a new CGI handler program for a particular file type.
The
.Ar suffix
should be any normal file suffix, and the
.Ar cgihandler
should be a full path to an interpreter.
This option is the only way to enable CGI programs that exist
outside of the cgibin directory to be executed.
Multiple
.Fl C
options may be passed.
.It Fl c Ar cgibin
Enables the CGI/1.1 interface.
The
.Ar cgibin
directory is expected to contain the CGI programs to be used.
.Nm
looks for URL's in the form of
.Em /cgi-bin/<scriptname>
where
.Aq scriptname
is a valid CGI program in the
.Ar cgibin
directory.
In other words, all CGI URL's must begin with
.Em \%/cgi-bin/ .
Note that the CGI/1.1 interface is available with
.Em ~user
translation using
.Fl E
switch.
.It Fl d
Enables debug support.
.It Fl E
Enables CGI/1.1 interface for
.Em ~user
translation.
Note that enabling this support implies that users can run commands
as the web server user.
This may have security implications.
.It Fl e
Causes
.Nm
to not clear the environment when used with either the
.Fl t
or
.Fl U
options.
.It Fl f
Stops the
.Fl b
flag from detaching
.Nm
from the tty and going into the background.
This implies the
.Fl b
flag.
.It Fl G
Get the
.Nm
version string, print it on standard output, and exit.
.It Fl H
Causes directory index mode to hide files and directories
that start with a period, except for
.Pa .. .
Also see
.Fl X .
.It Fl I Ar port
Causes
.Nm
to use
.Ar port
instead of the default
.Dq http
port.
When used with the
.Fl b
option, it changes the bound port.
Otherwise it forces redirections to use this port instead of the
value obtained via
.Xr getsockname 2 .
.It Fl i Ar address
Causes
.Ar address
to be used as the address to bind daemon mode.
If otherwise unspecified, the address used to bind is derived from the
.Ar myname ,
which defaults to the name returned by
.Xr gethostname 3 .
Only the last
.Fl i
option is used.
This option is only valid with the
.Fl b
option.
.It Fl L Ar prefix script
Adds a new Lua script for a particular prefix.
The
.Ar prefix
should be an arbitrary text, and the
.Ar script
should be a full path to a Lua script.
Multiple
.Fl L
options may be passed.
A separate Lua state is created for each prefix.
The Lua script can register callbacks using the
httpd.register_handler('<name>', function) Lua function,
which will trigger the execution of the Lua function
.Em function
when a URL in the form
.Em http://<hostname>/<prefix>/<name>
is being accessed.
The function is passed three tables as arguments, the server
environment, the request headers, and the decoded query string
plus any data that was sent as application/x-www-form-urlencoded.
.It Fl M Ar suffix type encoding encoding11
Adds a new entry to the table that converts file suffixes to
content type and encoding.
This option takes four additional arguments containing
the file prefix, its
.Dq Content-Type ,
.Dq Content-Encoding ,
and
.Dq Content-Encoding
for HTTP/1.1 connections, respectively.
If any of these are a single dash
.Pq Dq - ,
the empty string is used instead.
Multiple
.Fl M
options may be passed.
.It Fl m Ar version
Set the minimum supported SSL protocol
.Ar version .
The valid values of
.Ar version
are
.Dq TLSv1.1 ,
.Dq TLSv1.2 ,
and
.Dq TLSv1.3 .
The default version is
.Dq TLSv1.1 .
.It Fl n
Stops
.Nm
from doing IP address to name resolution of remote hosts.
This affects the
.Ev REMOTE_HOST
environment variable for CGI programs and Lua scripts.
.It Fl P Ar pidfile
Causes
.Nm
to create a PID file in
.Ar pidfile
when run in daemon mode with the
.Fl b
option.
.It Fl p Ar pubdir
Changes the default user directory for
.Em /~user/
translations from
.Dq public_html
to
.Ar pubdir .
.It Fl q
Quiet mode - no log entries generated.
.It Fl R Ar readme
When directory indexing is enabled, include the contents of the file
.Ar readme
in the footer of the directory index.
.It Fl S Ar version
Sets the internal server version to
.Ar version .
.It Fl s
Forces logging to be set to stderr always.
.It Fl T Ar type timeout
Set the timeout for
.Ar type
to
.Ar timeout .
The valid values of
.Ar type
are
.Dq ssl timeout ,
.Dq initial timeout ,
.Dq header timeout ,
and
.Dq request timeout .
The default values are 30 seconds, 30 seconds, 10 seconds and 600 seconds,
respectively.
.It Fl t Ar chrootdir
Makes
.Nm
chroot to the specified directory
before answering requests.
Every other path should be specified relative
to the new root, if this option is used.
Note that the current environment
is normally replaced with an empty environment with this option, unless the
.Fl e
option is also used.
.It Fl U Ar username
Causes
.Nm
to switch to the user and the groups of
.Ar username
after initialization.
This option, like
.Fl t
above, causes
.Nm
to clear the environment unless the
.Fl e
option is given.
.It Fl u
Enables the transformation of Uniform Resource Locators of
the form
.Em /~user/
into the directory
.Pa ~user/public_html
(but see the
.Fl p
option above).
.It Fl V
Sets the backup virtual host directory to the
.Ar slashdir
argument.
If no directory exists in
.Ar virtualroot
for the request, then
.Ar slashdir
will be used.
The default behavior is to return 404 (Not Found.)
.It Fl v Ar virtualroot
Enables virtual hosting support.
Directories in
.Ar virtualroot
will be searched for a matching virtual host name, when parsing
the HTML request.
If a matching name is found, it will be used
as both the server's real name,
.Op Ar myname ,
and as the
.Ar slashdir .
See the
.Sx EXAMPLES
section for an example of using this option.
.It Fl X
Enables directory indexing.
A directory index will be generated only when the default file (i.e.
.Pa index.html
normally) is not present.
.It Fl x Ar index
Changes the default file read for directories from
.Dq index.html
to
.Ar index .
.It Fl Z Ar certificate_path privatekey_path
Sets the path to the server certificate file and the private key file
in PEM format.
It also causes
.Nm
to start SSL mode.
.It Fl z Ar ciphers
Sets the list of SSL ciphers (see
.Xr SSL_CTX_set_cipher_list 3 ) .
.El
.Pp
Note that in
.Nm
versions 20031005 and prior that supported the
.Fl C
and
.Fl M
options, they took a single space-separated argument that was parsed.
since version 20040828, they take multiple options (2 in the case of
.Fl C
and 4 in the case of
.Fl M . )
.Ss INETD CONFIGURATION
As
.Nm
uses
.Xr inetd 8
by default to process incoming TCP connections for HTTP requests
(but see the
.Fl b
option),
.Nm
has little internal networking knowledge.
(Indeed, you can run it on the command line with little change of
functionality.)
A typical
.Xr inetd.conf 5
entry would be:
.Bd -literal
http stream tcp  nowait:600 _httpd /usr/libexec/httpd httpd /var/www
http stream tcp6 nowait:600 _httpd /usr/libexec/httpd httpd /var/www
.Ed
.Pp
This would serve web pages from
.Pa /var/www
on both IPv4 and IPv6 ports.
The
.Em :600
changes the
requests per minute to 600, up from the
.Xr inetd 8
default of 40.
.Pp
Using the
.Nx
.Xr inetd 8 ,
you can provide multiple IP-address based HTTP servers by having multiple
listening ports with different configurations.
.Ss NOTES
This server supports the
.Em HTTP/0.9 ,
.Em HTTP/1.0 ,
and
.Em HTTP/1.1
standards.
Support for these protocols is very minimal and many optional features are
not supported.
.Pp
.Nm
can be compiled without
CGI support (NO_CGIBIN_SUPPORT),
user transformations (NO_USER_SUPPORT),
directory index support (NO_DIRINDEX_SUPPORT),
daemon mode support (NO_DAEMON_MODE),
dynamic MIME content (NO_DYNAMIC_CONTENT),
Lua support (NO_LUA_SUPPORT),
and SSL support (NO_SSL_SUPPORT)
by defining the listed macros when building
.Nm .
.Ss HTTP BASIC AUTHORIZATION
.Nm
has support for HTTP Basic Authorization.
If a file named
.Pa .htpasswd
exists in the directory of the current request,
.Nm
will restrict access to documents in that directory
using the RFC 2617 HTTP
.Dq Basic
authentication scheme.
.Pp
Note:
This does not recursively protect any sub-directories.
.Pp
The
.Pa .htpasswd
file contains lines delimited with a colon containing
user names and passwords hashed with
.Xr crypt 3 ,
for example:
.Bd -literal
heather:$1$pZWI4tH/$DzDPl63i6VvVRv2lJNV7k1
jeremy:A.xewbx2DpQ8I
.Ed
.Pp
On
.Nx ,
the
.Xr pwhash 1
utility may be used to generate hashed passwords.
.Pp
While
.Nm
distributed with
.Nx
has support for HTTP Basic Authorization enabled by default,
in the portable distribution it is excluded.
Compile
.Nm
with
.Dq -DDO_HTPASSWD
on the compiler command line to enable this support.
It may require linking with the crypt library, using
.Dq -lcrypt .
.Ss BLOCKLIST SUPPORT
On
.Nx ,
.Nm
supports
.Xr blocklistd 8
by default.
The support can be disabled with the
.Dq -DNO_BLOCKLIST_SUPPORT
compilation option.
.Pp
Upon occurrence,
.Nm
reports two HTTP status codes to
.Xr blocklistd 8
as failures:
.Em 401
(``Unauthorized'')
and
.Em 403
(``Forbidden'') .
Of these,
.Em 401
is the one received upon authorization failure with the
HTTP Basic Authorization mechanism.
A successful authorization decreases the counter kept by
.Xr blocklistd 8 .
.Pp
Note that the implementation of the HTTP Basic Authorization mechanism
uses a redirection; a status code
.Em 401
is always initially received.
Therefore, a single authorization failure of
.Pa .htpasswd
is reported as two failures to
.Xr blocklistd 8 ,
but no failures are recorded upon successful authorization
due to the decrease of the failure counter.
.Ss SSL SUPPORT
.Nm
has support for TLSv1.1 and TLSv1.2 protocols that are included by
default.
It requires linking with the crypto and ssl library, using
.Dq -lcrypto -lssl .
To disable SSL SUPPORT compile
.Nm
with
.Dq -DNO_SSL_SUPPORT
on the compiler command line.
.Pp
To have an enforced redirect, such as http to https, create a shadow
directory root that contains a
.Pa .bzabsredirect
file that points to the real target.
.Ss COMPRESSION
.Nm
supports a very basic form of compression.
.Nm
will serve the requested file postpended with
.Dq Pa .gz
if it exists, it is readable, the client requested gzip compression, and
the client did not make a ranged request.
.Sh FILES
.Nm
looks for a couple of special files in directories that allow certain features
to be provided on a per-directory basis.
The
.Pa .htpasswd
file is used by HTTP basic authorization.
If a
.Pa .bzredirect
symbolic link is found,
.Nm
will perform a smart redirect to the target of this symlink.
The target is assumed to live on the same server.
If target starts with slash then absolute redirection is performed,
otherwise it's handled as relative.
If a
.Pa .bzabsredirect
symbolic link is found,
.Nm
will redirect to the absolute URL pointed to by this symlink.
This is useful to redirect to different servers.
Two forms of redirection are supported - symbolic link without schema will use
.Em http://
as default i.e. link to
.Em NetBSD.org
will redirect to
.Em http://NetBSD.org/
Otherwise provided schema will be used i.e. symbolic link to
.Em ftp://NetBSD.org/
will redirect to the provided URL.
If a
.Pa .bzremap
file is found at the root of a (virtual) server, it is expected to contain
rewrite mappings for URLs.
.Pp
These remappings are performed internally in the server before authentication
happens and can be used to hide implementation details, like the CGI handler
specific suffix for non cgi scripts in authorized directories.
.Pp
The map file consists of lines two paths separated by a colon, where the left
side needs to exactly match a (sub) path of the request and will be replaced
by the right side.
.Pp
The first match always wins.
.Pp
A
.Pa .bzremap
file could look like this:
.Bd -literal
/nic/update:/auth-dir/updipv4.pl
.Ed
.Pp
The remap file should be short, access to it is slow and needs to happen
on each request.
If a request path needs to include a colon
.Pq Li \&:
character, it can be escaped
with a backslash
.Pq Li \e
The right hand side of the colon is always used verbatim, no escape sequences
are interpreted.
.Sh EXAMPLES
To configure set of virtual hosts, one would use an
.Xr inetd.conf 5
entry like:
.Bd -literal
http stream tcp  nowait:600 _httpd /usr/libexec/httpd httpd -v /var/vroot /var/www
.Ed
.Pp
and inside
.Pa /var/vroot
create a directory (or a symlink to a directory) with the same name as
the virtual host, for each virtual host.
Lookups for these names are done in a case-insensitive manner, and may
include the port number part of the request, allowing for distinct
virtual hosts on the same name.
.Pp
To use
.Nm
with PHP, one must use the
.Fl C
option to specify a CGI handler for a particular file type.
Typically this will be like:
.Bd -literal
httpd -C .php /usr/pkg/bin/php-cgi /var/www
.Ed
.Pp
Note that a plain script interpreter can not be used directly as a cgihandler,
as there are no command line options passed from
.Nm
to avoid security issues.
.Pp
If no CGI-aware wrapper exists, a simple shell script like the following
might do.
.Pp
It would be invoked like:
.Bd -literal
httpd -C .pl /www-scripts/bin/run.perl /var/www
.Ed
and the script could look like:
.Bd -literal
#! /bin/sh

if [ -r "$SCRIPT_FILENAME" -a -x "$SCRIPT_FILENAME" ]; then
	exec /usr/pkg/bin/perl "$SCRIPT_FILENAME"
fi

exit 1
.Ed

.Sh SEE ALSO
.Xr inetd.conf 5 ,
.Xr inetd 8
.Sh HISTORY
.Nm
was first written in perl, based on another perl http server
called
.Dq tinyhttpd .
It was then rewritten from scratch in perl, and then once again in C.
From
.Dq bozohttpd
version 20060517, it has been integrated into
.Nx .
The focus has always been simplicity and security, with minimal features
and regular code audits.
This manual documents
.Nm
version 20230602.
.Sh AUTHORS
.An -nosplit
.Nm
was written by
.An Matthew R. Green
.Aq Mt mrg@eterna.com.au .
.Pp
The large list of contributors includes:
.Bl -dash
.It
.An Christoph Badura
.Aq Mt bad@bsd.de
provided Range: header support
.It
.An Marc Balmer
.Aq Mt mbalmer@NetBSD.org
added Lua support for dynamic content creation
.It
.An Sean Boudreau
.Aq Mt seanb@NetBSD.org
provided a security fix for virtual hosting
.It
.An Julian Coleman
.Aq Mt jdc@coris.org.uk
provided an IPv6 bugfix
.It
.An Chuck Cranor
.Aq Mt chuck@research.att.com
provided cgi-bin support fixes, and more
.It
.An Alistair G. Crooks
.Aq Mt agc@NetBSD.org
cleaned up many internal interfaces, made
.Nm
linkable as a library and provided the Lua binding
.It
.An DEGROOTE Arnaud
.Aq Mt degroote@NetBSD.org
provided a fix for daemon mode
.It
.An Andrew Doran
.Aq Mt ad@NetBSD.org
provided directory indexing support
.It
.An Roland Dowdeswell
.Aq Mt elric@NetBSD.org
added support for serving gzipped files and better SSL handling
.It
.An Per Ekman
.Aq Mt pek@pdc.kth.se
provided a fix for a minor (non-security) buffer overflow condition
.It
.Aq Mt emily@ingalls.rocks
provided fixes for some bad request parsing
.It
.An Jun-ichiro itojun Hagino, KAME
.Aq Mt itojun@iijlab.net
provided initial IPv6 support
.It
.An Martin Husemann
.Aq Mt martin@NetBSD.org
provided .bzabsredirect and .bzredir support, fixed various
redirection issues and more
.It
.An Arto Huusko
.Aq Mt arto.huusko@pp2.inet.fi
provided fixes cgi-bin
.It
.An Roland Illig
.Aq Mt roland.illig@gmx.de
provided some off-by-one fixes
.It
.An Zak Johnson
.Aq Mt zakj@nox.cx
provided cgi-bin enhancements
.It
.An Nicolas Jombart
.Aq Mt ecu@ipv42.net
provided fixes for HTTP basic authorization support
.It
.An Antti Kantee
.Aq Mt pooka@NetBSD.org
provided fixes for HTTP basic authorization support
.It
.An Thomas Klausner
.Aq Mt wiz@NetBSD.org
provided many fixes and enhancements for the man page
.It
.An Mateusz Kocielski
.Aq Mt shm@NetBSD.org
fixed memory leaks, various issues with userdir support,
information disclosure issues, added support for using CGI handlers
with directory indexing, found several security issues and provided
various other fixes
.It
.An Arnaud Lacombe
.Aq Mt alc@NetBSD.org
provided some clean up for memory leaks
.It
.An Johnny Lam
.Aq Mt jlam@NetBSD.org
provided man page fixes
.It
.An Dennis Lindroos
.Aq Mt denafcm@gmail.com
provided a cgi-bin fix
.It
.An Jared McNeill
.Aq Mt jmcneill@NetBSD.org
added support for readme in directory indexing
.It
.An Julio Merino
.Aq Mt jmmv@NetBSD.org
Added the
.Fl P
option (pidfile support) and provided some man page fixes
.It
.An Luke Mewburn
.Aq Mt lukem@NetBSD.org
provided many various fixes, including cgi-bin fixes and enhancements,
HTTP basic authorization support and much code clean up
.It
.An Sunil Nimmagadda
.Aq Mt sunil@nimmagadda.net
provided runtime TLS version control
.It
.An Rajeev V. Pillai
.Aq Mt rajeev_v_pillai@yahoo.com
provided several fixes for virtual hosting and directory indexing and
fixes for CGI
.It
.An Jeremy C. Reed
.Aq Mt reed@NetBSD.org
provided several clean up fixes, and man page updates
.It
.An Scott Reynolds
.Aq Mt scottr@NetBSD.org
provided various fixes
.It
.An Tyler Retzlaff
.Aq Mt rtr@eterna.com.au
provided SSL support, cgi-bin fixes and much other random other stuff
.It
.An rudolf
.Aq Mt netbsd@eq.cz
provided minor compile fixes and a CGI content map fix
.It
.An Steve Rumble
.Aq Mt rumble@ephemeral.org
provided the
.Fl V
option
.It
.An Jukka Ruohonen
.Aq Mt jruoho@NetBSD.org
provided support for
.Xr blocklistd 8
.It
.An Thor Lancelot Simon
.Aq Mt tls@NetBSD.org
enhanced cgi-bin support
.It
.An Joerg Sonnenberger
.Aq Mt joerg@NetBSD.org
implemented If-Modified-Since support
.It
.An Kimmo Suominen
.Aq Mt kim@NetBSD.org
removed obsolete
.Pa .bzdirect
handling
.It
.An ISIHARA Takanori
.Aq Mt ishit@oak.dti.ne.jp
provided a man page fix
.It
.An Holger Weiss
.Aq Mt holger@CIS.FU-Berlin.DE
provided http authorization fixes
.It
.Aq Mt xs@kittenz.org
provided chroot and change-to-user support, and other various fixes
.It
.An S.P.Zeidler
.Aq Mt spz@NetBSD.org
fixed several SSL shutdown issues
.It
Coyote Point provided various CGI fixes
.El
.Pp
There are probably others I have forgotten (let me know if you care)
.Pp
Please send all updates to
.Nm
to
.Aq Mt mrg@eterna.com.au
for inclusion in future releases.
.Sh BUGS
.Nm
does not handle HTTP/1.1 chunked input from the client yet.