smime

来自「支持SSL v2/v3, TLS, PKCS #5, PKCS #7, PKCS」· 代码 · 共 574 行 · 第 1/2 页

#!/usr/local/bin/perl

# The contents of this file are subject to the Mozilla Public
# License Version 1.1 (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.mozilla.org/MPL/
# 
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
# 
# The Original Code is the Netscape security libraries.
# 
# The Initial Developer of the Original Code is Netscape
# Communications Corporation.  Portions created by Netscape are 
# Copyright (C) 1994-2000 Netscape Communications Corporation.  All
# Rights Reserved.
# 
# Contributor(s):
# 
# Alternatively, the contents of this file may be used under the
# terms of the GNU General Public License Version 2 or later (the
# "GPL"), in which case the provisions of the GPL are applicable 
# instead of those above.  If you wish to allow use of your 
# version of this file only under the terms of the GPL and not to
# allow others to use your version of this file under the MPL,
# indicate your decision by deleting the provisions above and
# replace them with the notice and other provisions required by
# the GPL.  If you do not delete the provisions above, a recipient
# may use your version of this file under either the MPL or the
# GPL.

#
# smime.pl - frontend for S/MIME message generation and parsing
#
# $Id: smime,v 1.6 2000/07/07 00:57:39 chrisk%netscape.com Exp $
#

use Getopt::Std;

@boundarychars = ( "0" .. "9", "A" .. "F" );

# path to cmsutil
$cmsutilpath = "cmsutil";

#
# Thanks to Gisle Aas <[e-mail]> for the base64 functions
# originally taken from MIME-Base64-2.11 at www.cpan.org
#
sub encode_base64($)
{
    my $res = "";
    pos($_[0]) = 0;                          # ensure start at the beginning
    while ($_[0] =~ /(.{1,45})/gs) {
	$res .= substr(pack('u', $1), 1);    # get rid of length byte after packing
	chop($res);
    }
    $res =~ tr|` -_|AA-Za-z0-9+/|;
    # fix padding at the end
    my $padding = (3 - length($_[0]) % 3) % 3;
    $res =~ s/.{$padding}$/'=' x $padding/e if $padding;
    # break encoded string into lines of no more than 76 characters each
    $res =~ s/(.{1,76})/$1\n/g;
    $res;
}

sub decode_base64($)
{
    local($^W) = 0; # unpack("u",...) gives bogus warning in 5.00[123]

    my $str = shift;
    my $res = "";

    $str =~ tr|A-Za-z0-9+=/||cd;            # remove non-base64 chars
    if (length($str) % 4) {
	require Carp;
	Carp::carp("Length of base64 data not a multiple of 4")
    }
    $str =~ s/=+$//;                        # remove padding
    $str =~ tr|A-Za-z0-9+/| -_|;            # convert to uuencoded format
    while ($str =~ /(.{1,60})/gs) {
	my $len = chr(32 + length($1)*3/4); # compute length byte
	$res .= unpack("u", $len . $1 );    # uudecode
    }
    $res;
}

#
# parse headers into a hash
#
# %headers = parseheaders($headertext);
#
sub parseheaders($)
{
    my ($headerdata) = @_;
    my $hdr;
    my %hdrhash;
    my $hdrname;
    my $hdrvalue;
    my @hdrvalues;
    my $subhdrname;
    my $subhdrvalue;

    # the expression in split() correctly handles continuation lines
    foreach $hdr (split(/\n(?=\S)/, $headerdata)) {
	$hdr =~ s/\r*\n\s+/ /g;	# collapse continuation lines
	($hdrname, $hdrvalue) = $hdr =~ m/^(\S+):\s+(.*)$/;

	# ignore non-headers (or should we die horribly?)
	next unless (defined($hdrname));
	$hdrname =~ tr/A-Z/a-z/;			# lowercase the header name
	@hdrvalues = split(/\s*;\s*/, $hdrvalue);	# split header values (XXXX quoting)

	# there is guaranteed to be at least one value
	$hdrvalue = shift @hdrvalues;
	if ($hdrvalue =~ /^\s*\"(.*)\"\s*$/) {		# strip quotes if there
	    $hdrvalue = $1;
	}

	$hdrhash{$hdrname}{MAIN} = $hdrvalue;
	# print "XXX $hdrname = $hdrvalue\n";

	# deal with additional name-value pairs
	foreach $hdrvalue (@hdrvalues) {
	    ($subhdrname, $subhdrvalue) = $hdrvalue =~ m/^(\S+)\s*=\s*(.*)$/;
	    # ignore non-name-value pairs (or should we die?)
	    next unless (defined($subhdrname));
	    $subhdrname =~ tr/A-Z/a-z/;
	    if ($subhdrvalue =~ /^\s*\"(.*)\"\s*$/) {	# strip quotes if there
		$subhdrvalue = $1;
	    }
	    $hdrhash{$hdrname}{$subhdrname} = $subhdrvalue;
	}

    }
    return %hdrhash;
}

#
# encryptentity($entity, $options) - encrypt an S/MIME entity,
#                                    creating a new application/pkcs7-smime entity
#
# entity  - string containing entire S/MIME entity to encrypt
# options - options for cmsutil
#
# this will generate and return a new application/pkcs7-smime entity containing
# the enveloped input entity.
#
sub encryptentity($$)
{
    my ($entity, $cmsutiloptions) = @_;
    my $out = "";
    my $boundary;

    $tmpencfile = "/tmp/encryptentity.$$";

    #
    # generate a random boundary string
    #
    $boundary = "------------ms" . join("", @boundarychars[map{rand @boundarychars }( 1 .. 24 )]);

    #
    # tell cmsutil to generate a enveloped CMS message using our data
    #
    open(CMS, "|$cmsutilpath -E $cmsutiloptions -o $tmpencfile") or die "ERROR: cannot pipe to cmsutil";
    print CMS $entity;
    unless (close(CMS)) {
	print STDERR "ERROR: encryption failed.\n";
	unlink($tmpsigfile);
	exit 1;
    }

    $out  = "Content-Type: application/pkcs7-mime; smime-type=enveloped-data; name=smime.p7m\n";
    $out .= "Content-Transfer-Encoding: base64\n";
    $out .= "Content-Disposition: attachment; filename=smime.p7m\n";
    $out .= "\n";			# end of entity header

    open (ENC, $tmpencfile) or die "ERROR: cannot find newly generated encrypted content";
    local($/) = undef;			# slurp whole file
    $out .= encode_base64(<ENC>), "\n";	# entity body is base64-encoded CMS message
    close(ENC);

    unlink($tmpencfile);

    $out;
}

#
# signentity($entity, $options) - sign an S/MIME entity
#
# entity  - string containing entire S/MIME entity to sign
# options - options for cmsutil
#
# this will generate and return a new multipart/signed entity consisting
# of the canonicalized original content, plus a signature block.
#
sub signentity($$)
{
    my ($entity, $cmsutiloptions) = @_;
    my $out = "";
    my $boundary;

    $tmpsigfile = "/tmp/signentity.$$";

    #
    # generate a random boundary string
    #
    $boundary = "------------ms" . join("", @boundarychars[map{rand @boundarychars }( 1 .. 24 )]);

    #
    # tell cmsutil to generate a signed CMS message using the canonicalized data
    # The signedData has detached content (-T) and includes a signing time attribute (-G)
    #
    # if we do not provide a password on the command line, here's where we would be asked for it
    #
    open(CMS, "|$cmsutilpath -S -T -G $cmsutiloptions -o $tmpsigfile") or die "ERROR: cannot pipe to cmsutil";
    print CMS $entity;
    unless (close(CMS)) {
	print STDERR "ERROR: signature generation failed.\n";
	unlink($tmpsigfile);
	exit 1;
    }

    open (SIG, $tmpsigfile) or die "ERROR: cannot find newly generated signature";

    #
    # construct a new multipart/signed MIME entity consisting of the original content and
    # the signature
    #
    # (we assume that cmsutil generates a SHA1 digest)
    $out .= "Content-Type: multipart/signed; protocol=\"application/pkcs7-signature\"; micalg=sha1; boundary=\"${boundary}\"\n";
    $out .= "\n";		# end of entity header
    $out .= "This is a cryptographically signed message in MIME format.\n"; # explanatory comment
    $out .= "\n--${boundary}\n";
    $out .= $entity;
    $out .= "\n--${boundary}\n";
    $out .= "Content-Type: application/pkcs7-signature; name=smime.p7s\n";
    $out .= "Content-Transfer-Encoding: base64\n";
    $out .= "Content-Disposition: attachment; filename=smime.p7s\n";
    $out .= "Content-Description: S/MIME Cryptographic Signature\n";
    $out .= "\n";		# end of signature subentity header

    local($/) = undef;		# slurp whole file
    $out .= encode_base64(<SIG>);	# append base64-encoded signature
    $out .= "\n--${boundary}--\n";

    close(SIG);
    unlink($tmpsigfile);

    $out;
}

sub usage {
    print STDERR "usage: smime [options]\n";
    print STDERR " options:\n";
    print STDERR " -S nick             generate signed message, use certificate named \"nick\"\n";
    print STDERR "  -p passwd          use \"passwd\" as security module password\n";
    print STDERR " -E rec1[,rec2...]   generate encrypted message for recipients\n";
    print STDERR " -D                  decode a S/MIME message\n";
    print STDERR " -C pathname         set pathname of \"cmsutil\"\n";
    print STDERR " -d directory        set directory containing certificate db\n";
    print STDERR "                     (default: ~/.netscape)\n";
    print STDERR "\nWith -S or -E, smime will take a regular RFC822 message or MIME entity\n";
    print STDERR "on stdin and generate a signed or encrypted S/MIME message with the same\n";
    print STDERR "headers and content from it. The output can be used as input to a MTA.\n";
    print STDERR "-D causes smime to strip off all S/MIME layers if possible and output\n";
    print STDERR "the \"inner\" message.\n";
}

#
# start of main procedures
#

#
# process command line options
#
unless (getopts('S:E:p:d:C:D')) {
    usage();
    exit 1;
}

unless (defined($opt_S) or defined($opt_E) or defined($opt_D)) {
    print STDERR "ERROR: -S and/or -E, or -D must be specified.\n";
    usage();
    exit 1;
}