X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=cgi-auth-flexible.git;a=blobdiff_plain;f=cgi-auth-hybrid.pm;h=2e0623d71a7db71b9f7a2504ef1cb87819995841;hp=bf2bdd65bb73f9f3edd82d0e8ffdba00e0824298;hb=017d2716636658b54c7b41fe9cc6ef55fc971971;hpb=33bc626134e855b61dedc97513f81ee33e738e6a

diff --git a/cgi-auth-hybrid.pm b/cgi-auth-hybrid.pm
index bf2bdd6..2e0623d 100644
--- a/cgi-auth-hybrid.pm
+++ b/cgi-auth-hybrid.pm
@@ -32,7 +32,9 @@ our @EXPORT_OK;
 use DBI;
 use CGI;
 
-sub new {
+#---------- verifier object methods ----------
+
+sub new_verifier {
     my $class = shift;
     my $s = {
 	S => {
@@ -45,15 +47,15 @@ sub new {
 	    associdlen => 128, # bits
 	    login_timeout => 86400, # seconds
 	    param_name => 'cah_associd',
+	    promise_check_mutate => 0,
 	    cookie_name => 'cah_associd', # make undef to disable cookie
-	    cgi => undef,
-	    get_param => sub { $s->_c()->param($s->{S}{param_name}) },
+	    get_param => sub { $_[0]->param($s->{S}{param_name}) },
 	    get_cookie => sub { $s->{S}{cookie_name}
-				? $s->_c()->cookie($s->{S}{cookie_name})
+				? $_[0]->cookie($s->{S}{cookie_name})
 				: '' },
-	    get_method => sub { $s->_c()->request_method() },
+	    get_method => sub { $_[0]->request_method() },
 	},
-	D => undef,
+	Dbh => undef,
     };
     my ($k,$v);
     while (($k,$v,@_) = @_) {
@@ -61,17 +63,13 @@ sub new {
 	$s->{S}{$k} = $v;
     }
     bless $s, $class;
+    $s->_dbopen();
     return $s;
 }
 
-sub _c ($) {
-    my ($s) = @_;
-    return $s->{S}{cgi};
-}
-
 sub _dbopen ($) {
     my ($s) = @_;
-    my $dbh = $s->{D};
+    my $dbh = $s->{Dbh};
     return $dbh if $dbh; 
 
     $s->{S}{assocdb_dsn} ||= "dbi:SQLite:dbname=$s->{S}{assocdb_path}";
@@ -82,7 +80,7 @@ sub _dbopen ($) {
 			 AutoCommit => 0, RaiseError => 1,
 		     });
     die "${assocdb_dsn} $! ?" unless $dbh;
-    $s->{D} = $dbh;
+    $s->{Dbh} = $dbh;
 
     $dbh->do("BEGIN");
 
@@ -96,93 +94,300 @@ sub _dbopen ($) {
     return $dbh;
 }
 
+#---------- request object methods ----------
+
+sub new_request {
+    my ($classbase, $cgi, @extra) = @_;
+    if (!ref $classbase) {
+	$classbase = $classbase->new_verifier(@extra);
+    } else {
+	die if @extra;
+    }
+    my $r = {
+	S => $classbase->{S},
+	Dbh => $classbase->{Dbh},
+	Cgi => $cgi,
+    };
+    bless $r, ref $classbase;
+}
+
+sub _cm ($$@) {
+    my ($r,$methname, @args) = @_;
+    my $methfunc = $r->{S}{$methname};
+    return $methfunc->($r->{Cgi}, $r, @args);
+}
+
 sub record_login ($$) {
-    my ($s,$nusername) = @_;
-    my $rsp = $s->{S}{random_source};
+    my ($r,$nusername) = @_;
+    my $rsp = $r->{S}{random_source};
     my $rsf = new IO::File $rsp, '<' or die "$rsp $!";
-    my $bytes = ($s->{S}{associdlen} + 7) >> 3;
+    my $bytes = ($r->{S}{associdlen} + 7) >> 3;
     my $nassocbin;
     $!=0;
     read($rsf,$nassocbin,$bytes) == $bytes or die "$rsp $!";
     close $rsf;
     my $nassoc = unpack "H*", $nassocbin;
-    my $dbh = $s->_dbopen();
-    $dbh->do("INSERT INTO $s->{S}{assocdb_table}".
+    my $dbh = $r->{Dbh};
+    $dbh->do("INSERT INTO $r->{S}{assocdb_table}".
 	     " (associd, username, last) VALUES (?,?,?)", {},
 	     $nassoc, $nusername, time);
     $dbh->do("COMMIT");
-    $s->{U} = $nusername;
-    $s->{A} = $nassoc;
+    $r->{U} = $nusername;
+    $r->{A} = $nassoc;
 }
 
-sub _check ($) {
-    my ($s) = @_;
-    my $qassoc = $s->{S}{param_get}();
-    if (!defined $qassoc) {
-	$qassoc = $s->{S}{cookie_get}();
+sub _check_core ($) {
+    my ($r) = @_;
+    my $qassoc = $r->_cm('get_param');
+    my ($nassoc,$nmutate);
+    if (!defined $r->{S}{cookie_name}) {
+	# authentication is by hidden form parameter only
 	return undef unless defined $qassoc;
-	return undef unless $s->{S}{get_method}() eq 'GET';
+	$nassoc = $qassoc;
+	$nmutate = 1;
+    } else {
+	# authentication is by cookie
+	# the cookie suffices for read-only GET requests
+	# for mutating and non-GET requests we require hidden param too
+	my $cassoc = $r->_cm('get_cookie');
+	return undef unless defined $cassoc;
+	$nassoc = $cassoc;
+	if (defined $qassoc && $qassoc eq $cassoc) {
+	    $nmutate = 1;
+	} else {
+	    return undef unless $r->{S}{promise_check_mutate};
+	    return undef unless $r->_cm('get_method') eq 'GET';
+	    $nmutate = 0;
+	}
     }
-    my $dbh = $s->_dbopen();
+
+# pages/param-sets are
+#   n normal non-mutating page
+#   r retrieval of information for JS, non-mutating
+#   m mutating page
+#   u update of information by JS, mutating
+#   i login
+#   o logout
+
+
+# in cook and par,
+#    a, aN     anything including -
+#    t, tN     temporary value (in our db, no logged in user yet)
+#    y, yN     value corresponds to logged-in user
+#    n, nN     value not in our db
+#    x, xN     t or y
+#    -         no value supplied
+# if N differs the case applies only when the two values differ
+# (eg,   a1 y2   does not apply when the logged-in value is supplied twice)
+
+# "stale session" means request originates from a page from a login
+# session which has been revoked (eg by logout); "cleared session"
+# means request originates from a browser which has a different (or
+# no) cookie.
+
+    # Case analysis, cookie mode, app promises re mutate:
+    # cook par meth  form
+    #                      
+    #  any -   POST  nrmuoi   bug or attack, fail
+    #  any -   GET    rmuoi   bug or attack, fail
+    #  any any GET     muoi   bug or attack, fail
+    #  any t   any   nrmuo    bug or attack, fail
+    #
+    #  a1  a2  POST      o    logout
+    #                           if a1 is valid, revoke it
+    #                           if a2 is valid, revoke it
+    #                           delete cookie
+    #                           redirect to "just logged out" page
+    #                             (which contains link to login form)
+    #
+    #  -   t   POST       i   complain about cookies being disabled
+    #
+    #  -   n   POST       i   complain about stale login form
+    #                           show new login form
+    #
+    #  x1  x2  POST       i   login (or switch user)
+    #                           revoke x1 if it was valid and !=x2
+    #                           upgrade x2 to y2 in our db (setting username)
+    #                           set cookie to x2
+    #                           redirect to GET of remaining params
+    #
+    #  t1  a2  ANY   nrmu     treat as  - a2 ANY
+    #
+    #  y   -   GET   n        cross-site link
+    #                           show data
+    #
+    #  y   y   GET   nr       fine, show page or send data
+    #  y   y   POST  nrmu     mutation is OK, do operation
+    #
+    #  y1  y2  GET   nr       request from stale page
+    #                           do not revoke y2 as not RESTful
+    #                           treat as   y1 n GET
+    #
+    #  y1  y2  POST  nrmu     request from stale page
+    #                           revoke y2
+    #                           treat as   y1 n POST
+    #
+    #  y   n   GET   n        intra-site link from stale page,
+    #                           treat as cross-site link, show data
+    #
+    #  y   n   POST  n m      intra-site form submission from stale page
+    #                           show "session interrupted"
+    #                           with link to main data page
+    #
+    #  y   n   GET    r       intra-site request from stale page
+    #                           fail
+    #
+    #  y   n   POST   r u     intra-site request from stale page
+    #                           fail
+    #
+    #  -/n y2  GET   nr       intra-site link from cleared session
+    #                           do not revoke y2 as not RESTful
+    #                           treat as   -/n n GET
+    #
+    #  -/n y2  POST  nrmu     request from cleared session
+    #                           revoke y2
+    #                           treat as   -/n n POST
+    #
+    #  -/n n   GET   n        cross-site link but user not logged in
+    #                           show login form with redirect to orig params
+    #
+    #  -/n n   GET    rmu     user not logged in
+    #                           fail
+    #
+    #  -/n n   POST  nrmu     user not logged in
+    #                           fail
+
+    my $dbh = $r->{Dbh};
     my ($nusername, $nlast) =
 	$dbh->selectrow_array("SELECT username, last".
-			      " FROM $s->{S}{assocdb_table}".
-			      " WHERE associd = ?", {}, $qassoc);
+			      " FROM $r->{S}{assocdb_table}".
+			      " WHERE associd = ?", {}, $nassoc);
     return undef unless defined $nusername;
-    my $timeout = $s->{S}{login_timeout};
+    my $timeout = $r->{S}{login_timeout};
     return undef unless !defined $timeout || time <= $nlast + $timeout;
 
-    return ($nusername, $qassoc);
+    # hooray
+    return ($nusername, $nassoc, $nmutate);
 }
 
-sub check ($) {
-    my ($s) = @_;
-
-    my ($nusername, $qassoc) = $s->_check() or return undef;
+sub _check ($) {
+    my ($r) = @_;
 
-    # hooray
-    $dbh->do("UPDATE $s->{S}{assocdb_table}".
-	     " SET last = ?".
-	     " WHERE associd = ?", {}, time, $qassoc);
-    $dbh->do("COMMIT");
+    return if exists $r->{Username};
+    ($r->{Username}, $r->{Assoc}, $r->{Mutate}) = $r->_check();
 
-    $s->{U} = $nusername;
-    $s->{A} = $qassoc;
-    return $username;
+    if (defined $r->{Assoc}) {
+	$dbh->do("UPDATE $r->{S}{assocdb_table}".
+		 " SET last = ?".
+		 " WHERE associd = ?", {}, time, $nassoc);
+	$dbh->do("COMMIT");
+    }
 }
 
 sub logout ($) {
-    my ($s) = @_;
+    my ($r) = @_;
 
-    if (my ($nusername, $qassoc) = $s->_check()) {
-	$dbh->do("DELETE FROM $s->{S}{assocdb_table}".
-		 " WHERE associd = ?", {}, $qassoc);
-	$dbh->do("COMMIT");
-    }
+    my ($nusername, $nassoc, $nmutate) = $r->_check();
+    return undef unless $nmutate;
+    $dbh->do("DELETE FROM $r->{S}{assocdb_table}".
+	     " WHERE associd = ?", {}, $nassoc);
+    $dbh->do("COMMIT");
+    return $nusername;
+}
+
+sub check ($) {
+    my ($r) = @_;
+    $r->_check();
+    return !!defined $r->{Username};
+}
+
+sub check_mutate ($) {
+    my ($r) = @_;
+    $r->check();
+    return $r->{Mutate};
 }
 
 sub username ($) {
-    my ($s) = @_;
-    return $s->{U};
+    my ($r) = @_;
+    $r->check();
+    return $r->{Username};
 
-sub hiddenv ($) {
-    my ($s) = @_;
-    return defined $s->{A} ? $s->{A} : '';
+sub hidden_val ($) {
+    my ($r) = @_;
+    $r->check();
+    return defined $r->{Assoc} ? $r->{Assoc} : '';
 }
 
-sub hiddena ($) {
-    my ($s) = @_;
-    return (-name => $s->{param_name},
-	    -default => $s->hiddenv());
+#---------- simple wrappers ----------
+
+sub hidden_hargs ($) {
+    my ($r) = @_;
+    return (-name => $r->{S}{param_name},
+	    -default => $r->hidden_val());
 }
 
-sub hiddenh ($) {
-    my ($s) = @_;
-    return hidden($s->hiddena());
+sub hidden_html ($) {
+    my ($r) = @_;
+    return hidden($r->hidden_hargs());
 }
 
-sub cookieac ($) {
-    my ($s) = @_;
-    return (-name => $s->{cookie_name},
-	    -value => hiddenv());
-	    
+sub cookiea_cargs ($) {
+    my ($r) = @_;
+    return (-name => $r->{S}{cookie_name},
+	    -value => hidden_val());
+}
+
+__END__
+
+=head1 NAME
+
+CGI::Auth::Hybrid - web authentication optionally using cookies
+
+=head1 SYNOPSYS
+
+ my $verifier = CGI::Auth::Hybrid->new_verifier(setting => value,...);
+ my $authreq = $verifier->new_request($cgi_request_object);
+
+ my $authreq = CGI::Auth::Hybrid->new_request($cgi_request_object,
+                                              setting => value,...);
+
+=head1 USAGE PATTERN FOR SIMPLE APPLICATIONS
+
+ if ( form submission is login request ) {
+     check login details, if wrong print error and quit
+     $authreq->record_login(...username...);
+ }
+ if ( form submission is logout request ) {
+     my $logged_out_user = $authreq->logout();
+     if (!defined $logged_out_user) {
+	 print "you are not logged in" error and quit
+     } else {
+	 print "goodbye $username you are now logged out" and quit
+     }
+ }
+ if ( !$authreq->check() ) {
+     display login form, quit
+
+
+=head1 USAGE PATTERN FOR FANCY APPLICATIONS
+
+ if ( form submission is login request ) {
+     check login details, if wrong print error and quit
+     $authreq->record_login(...username...);
+ }
+ if ( !$authreq->check() ) {
+     display login form, quit
+ if ( form submission is logout request ) {
+     die unless $authreq->mutate();
+     my $logged_out_user = $authreq->logout();
+     if (!defined $logged_out_user) {
+	 print "you are not logged in" error and quit
+     } else {
+	 print "goodbye $username you are now logged out" and quit
+     }
+ }
+
+
+advantages of cookie
+ - user can sort of log out by clearing cookies
+ - sophisticated applications can have get-requests