ljr/local/cgi-bin/LJ/Auth.pm

125 lines
3.9 KiB
Perl

# This is the LiveJournal Authentication module.
# It contains useful authentication methods.
package LJ::Auth;
use strict;
use Digest::HMAC_SHA1 qw(hmac_sha1_hex);
use Digest::SHA1 qw(sha1_hex);
use Carp qw (croak);
# Generate an auth token for AJAX requests to use.
# Arguments: ($remote, $action, %postvars)
# $remote: remote user object
# $uri: what uri this is for
# %postvars: the expected post variables
# Returns: Auth token good for the current hour
sub ajax_auth_token {
my ($class, $remote, $uri, %postvars) = @_;
$remote = LJ::want_user($remote) || LJ::get_remote();
croak "No URI specified" unless $uri;
my ($stime, $secret) = LJ::get_secret();
my $postvars = join('&', map { $postvars{$_} } sort keys %postvars);
my $remote_session_id = $remote && $remote->session ? $remote->session->id : LJ::UniqCookie->current_uniq;
my $remote_userid = $remote ? $remote->id : 0;
my $chalbare = qq {ajax:$stime:$remote_userid:$remote_session_id:$uri:$postvars};
my $chalsig = sha1_hex($chalbare, $secret);
return qq{$chalbare:$chalsig};
}
# Checks an auth token sent by an ajax request
# Arguments: $remote, $uri, %POST variables
# Returns: bool whether or not key is good
sub check_ajax_auth_token {
my ($class, $remote, $uri, %postvars) = @_;
$remote = LJ::want_user($remote) || LJ::get_remote();
# get auth token out of post vars
my $auth_token = delete $postvars{auth_token} or return 0;
# recompute post vars
my $postvars = join('&', map { $postvars{$_} } sort keys %postvars);
# get vars out of token string
my ($c_ver, $stime, $remoteid, $sessid, $chal_uri, $chal_postvars, $chalsig) = split(':', $auth_token);
# get secret based on $stime
my $secret = LJ::get_secret($stime);
# no time?
return 0 unless $stime && $secret;
# right version?
return 0 unless $c_ver eq 'ajax';
# in logged-out case $remoteid is 0 and $sessid is uniq_cookie
my $req_remoteid = $remoteid > 0 ? $remote->id : 0;
my $req_sessid = $remoteid > 0 ? $remote->session->id : LJ::UniqCookie->current_uniq;
# do signitures match?
my $chalbare = qq {$c_ver:$stime:$remoteid:$sessid:$chal_uri:$chal_postvars};
my $realsig = sha1_hex($chalbare, $secret);
return 0 unless $realsig eq $chalsig;
return 0 unless
$remoteid == $req_remoteid && # remote id matches or logged-out 0=0
$sessid == $req_sessid && # remote sessid or logged-out uniq cookie match
$uri eq $chal_uri && # uri matches
$postvars eq $chal_postvars; # post vars to uri
return 1;
}
# this is similar to the above methods but doesn't require a session or remote
sub sessionless_auth_token {
my ($class, $uri, %reqvars) = @_;
croak "No URI specified" unless $uri;
my ($stime, $secret) = LJ::get_secret();
my $reqvars = join('&', map { $reqvars{$_} } sort keys %reqvars);
my $chalbare = qq {sessionless:$stime:$uri:$reqvars};
my $chalsig = sha1_hex($chalbare, $secret);
return qq{$chalbare:$chalsig};
}
sub check_sessionless_auth_token {
my ($class, $uri, %reqvars) = @_;
# get auth token out of post vars
my $auth_token = delete $reqvars{auth_token} or return 0;
# recompute post vars
my $reqvars = join('&', map { $reqvars{$_} } sort keys %reqvars);
# get vars out of token string
my ($c_ver, $stime, $chal_uri, $chal_reqvars, $chalsig) = split(':', $auth_token);
# get secret based on $stime
my $secret = LJ::get_secret($stime);
# no time?
return 0 unless $stime && $secret;
# right version?
return 0 unless $c_ver eq 'sessionless';
# do signitures match?
my $chalbare = qq {$c_ver:$stime:$chal_uri:$chal_reqvars};
my $realsig = sha1_hex($chalbare, $secret);
return 0 unless $realsig eq $chalsig;
# do other vars match?
return 0 unless $uri eq $chal_uri && $reqvars eq $chal_reqvars;
return 1;
}
1;