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편집 파일: SSLBUILD

/* ========================================================================
 * Copyright 1988-2007 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
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SSL/TLS BUILD AND INSTALLATION NOTES FOR UNIX
			 Last Updated: 15 November 2007

PREREQUISITES BEFORE STARTING:
 1) Review the information in imap-2007/docs/BUILD.
 2) Obtain a copy of OpenSSL.  OpenSSL is available from third parties.  We
    do not provide OpenSSL.
 3) Make sure that you know how to build OpenSSL properly on the standard
    /usr/local/ssl directory.  In particular, /usr/local/ssl/include (and
    /usr/local/ssl/include/openssl) and /usr/local/ssl/lib must be set up
    from the OpenSSL build.  If you have a non-standard installation, then
    you must modify the imap-2007/src/osdep/unix/Makefile file to point
    to the appropriate locations.
 4) Make sure that you know how to obtain appropriate certificates on your
    system.

NOTE: We can NOT provide you with support in building/installing OpenSSL, or
in obtaining certificates.  If you need help in doing this, try the contacts
mentioned in the OpenSSL README.

SSL BUILD:

By default, the IMAP toolkit builds with SSL and disabling plaintext
passwords unless SSL/TLS encryption is in effect (SSLTYPE=nopwd).  This
produces an IMAP server which is compliant with RFC 3501 security
requirements.

To build with SSL but allow plaintext passwords in insecure sessions,
add "SSLTYPE=unix" to the make command line.  Note that doing so will
produce an IMAP server which is NON-COMPLIANT with RFC 3501.

To build without SSL, add "SSLTYPE=none" to the make command line.
Note that doing so will produce an IMAP server which is NON-COMPLIANT
with RFC 3501.

There are other make options relevant to SSL, described in
 imap-2007/src/osdep/unix/Makefile
The most important of these are SSLDIR, SSLCRYPTO, and SSLRSA.

SSLDIR is set to /usr/local/ssl by default.  This is the normal
installation directory for OpenSSL.  If your system uses a different directory
you will need to change this.

SSLCRYPTO is set to -lcrypto by default.  Older versions of MIT Kerberos
also have a libcrypto and will cause a library name conflict.  If you are
using an older version of Kerberos, you may need to change SSLCRYPTO to
$(SSLLIB)/libcrypto.a

SSLRSA is set empty by default.  It can be set to specify the RSAREF
libraries, which you once had to use with OpenSSL to use RSA algorithms
legally if you are in the USA, due to patent issues.  Since RSA Security Inc.
released the RSA algorithm into the public domain on September 6, 2000, there
is no longer any reason to do this.

SSL INSTALLATION:

Binaries from the build are:
	imap-2007/mtest/mtest		c-client testbed program
	imap-2007/ipopd/ipop2d		POP2 daemon
	imap-2007/ipopd/ipop3d		POP3 daemon
	imap-2007/imapd/imapd		IMAP4rev1 daemon

mtest is normally not used except by c-client developers.

STEP 1:	inetd setup

The ipop2d, ipop3d, and imapd daemons should be installed in a system
daemon directory and invoked by a listener such as xinetd or inetd.  In the
following examples, /usr/local/etc is used).

STEP 1(A): xinetd-specific setup

If your system uses xinetd, the daemons are invoked by files in your
/etc/xinetd.d directory with names corresponding to the service names (that
is: imap, imaps, pop2, pop3, pop3s).  You will need to consult your local
xinetd documentation to see what should go into these files.  Here is a a
sample /etc/xinetd.d/imaps file:

service imaps
{
	disable		= no
	socket_type	= stream
	wait		= no
	user		= root
	server		= /usr/local/etc/imapd
	groups		= yes
	flags		= REUSE IPv6
}

STEP 1(B): inetd-specific setup

If your system still uses inetd, the daemons are invoked by your
/etc/inetd.conf file with lines such as:

pop	stream	tcp	nowait	root	/usr/local/etc/ipop2d	ipop2d
pop3	stream	tcp	nowait	root	/usr/local/etc/ipop3d	ipop3d
imap	stream	tcp	nowait	root	/usr/local/etc/imapd	imapd
pop3s	stream	tcp	nowait	root	/usr/local/etc/ipop3d	ipop3d
imaps	stream	tcp	nowait	root	/usr/local/etc/imapd	imapd

Please refer to imap-2007/docs/BUILD for an important note about inetd's
limit on the number of new connections.  If that note applies to you, and you
can configure the number of connection in /etc/inetd.conf as described in
imap-2007/docs/build, here is the sample /etc/inetd.conf entry with SSL:

pop3	stream	tcp	nowait.100	root	/usr/local/etc/ipop3d	ipop3d
pop3s	stream	tcp	nowait.100	root	/usr/local/etc/ipop3d	ipop3d
imap	stream	tcp	nowait.100	root	/usr/local/etc/imapd	imapd
imaps	stream	tcp	nowait.100	root	/usr/local/etc/imapd	imapd
 (or, if you use TCP wrappers)
pop3	stream	tcp	nowait.100	root	/usr/local/etc/tcpd	ipop3d
imap	stream	tcp	nowait.100	root	/usr/local/etc/tcpd	imapd
pop3s	stream	tcp	nowait.100	root	/usr/local/etc/ipop3d	ipop3d
imaps	stream	tcp	nowait.100	root	/usr/local/etc/imapd	imapd

NOTE: do *NOT* use TCP wrappers (tcpd) for the imaps and pop3s services!  I
don't know why, but it doesn't work with TCP wrappers.

STEP 2:	services setup

You may also have to edit your /etc/services (or Yellow Pages,
NetInfo, etc. equivalent) to register these services, such as:

pop		109/tcp
pop3		110/tcp
imap		143/tcp
imaps		993/tcp
pop3s		995/tcp

NOTE: The SSL IMAP service *MUST* be called "imaps", and the SSL POP3 service
*MUST* be called "pop3s".

STEP 3: PAM setup

If your system has PAM (Pluggable Authentication Modules -- most
modern systems do) then you need to set up PAM authenticators for imap and
pop.  The correct file names are
	/etc/pam.d/imap
and
	/etc/pam.d/pop

It probably works to copy your /etc/pam.d/ftpd file to the above two
names.

Many people get these file names wrong, and then spend a lot of time
trying to figure out why it doesn't work.  Common mistakes are:
	/etc/pam.d/imapd
	/etc/pam.d/imap4
	/etc/pam.d/imap4rev1
	/etc/pam.d/imaps
	/etc/pam.d/ipop3d
	/etc/pam.d/pop3d
	/etc/pam.d/popd
	/etc/pam.d/pop3
	/etc/pam.d/pop3s

STEP 4:	certificates setup

NOTE: We can NOT provide you with support in obtaining certificates.  If you
need help in doing this, try the contacts mentioned in the OpenSSL README.

WARNING: Do NOT install servers built with SSL support unless you also plan to
install proper certificates!  It is NOT supported to run SSL-enabled servers
on a system without the proper certificates.

You must set up certificates on /usr/local/ssl/certs (this may be
different if you have a non-standard installation of OpenSSL; for example,
FreeBSD has modified OpenSSL to use /usr/local/certs).  You should install
both the certificate authority certificates from the SSL distribution after
building OpenSSL, plus your own certificates.  The latter should have been
purchased from a certificate authority, although self-signed certificates are
permissible.  A sample certificate file is at the end of this document.

Install the resulting certificate file on /usr/local/ssl/certs, with a
file name consisting of the server name and a suffix of ".pem".  For example,
install the imapd certificate on /usr/local/ssl/certs/imapd.pem and the ipop3d
certificate on /usr/local/ssl/certs/ipop3d.pem.  These files should be
protected against random people accessing them.  It is permissible for
imapd.pem and ipop3d.pem to be links to the same file.

The imapd.pem and ipop3d.pem must contain a private key and a
certificate.  The private key must not be encrypted.

The following command to openssl can be used to create a self-signed
certificate with a 10-year expiration:
	req -new -x509 -nodes -out imapd.pem -keyout imapd.pem -days 3650

*** IMPORTANT ***
     We DO NOT recommend, encourage, or sanction the use of self-signed
certificates.  Nor will we be responsible for any problems (including security
problems!) which result from your use of a self-signed certificate.  Use of
self-signed certificates should be limited to testing only.  Buy a real
certificate from a certificate authority!

*** IMPORTANT ***

If you have a multihomed system with multiple domain names (and hence
separate certificates for each domain name), you can append the IP address
to the service name.  For example, the IMAP certificate for [12.34.56.78]
would be /usr/local/ssl/certs/imapd-12.34.56.78.pem and so on.  You only need
to use this feature if you need to use multiple certificates (because different
DNS names are used).

SAMPLE CERTIFICATE FILE

Here is a sample certificate file.  Do *NOT* use this on your own
machine; it is simply an example of what one would look like.