fix bug #85: implement vnc tickets

Those tickets are restricted to a single resource path, and are only valid for
a short period of time (60s).

diff --git a/PVE/API2/AccessControl.pm b/PVE/API2/AccessControl.pm
index 5967c50ea30200caf6a2fb042b03edf176348d27..24699d215822658e51d672829545a7e87da4553d 100644 (file)
--- a/PVE/API2/AccessControl.pm
+++ b/PVE/API2/AccessControl.pm
@@ -81,13 +81,58 @@ __PACKAGE__->register_method ({
        return $res;
     }});
 
+
+my $verify_auth = sub {
+    my ($rpcenv, $username, $pw_or_ticket, $path, $privs) = @_;
+
+    my $normpath = PVE::AccessControl::normalize_path($path);
+
+    my $ticketuser;
+    if (($ticketuser = PVE::AccessControl::verify_ticket($pw_or_ticket, 1)) &&
+       ($ticketuser eq $username)) {
+       # valid ticket
+    } elsif (PVE::AccessControl::verify_vnc_ticket($pw_or_ticket, $username, $normpath, 1)) {
+       # valid vnc ticket
+    } else {
+       $username = PVE::AccessControl::authenticate_user($username, $pw_or_ticket);
+    }
+
+    my $privlist = [ PVE::Tools::split_list($privs) ];
+    if (!($normpath && scalar(@$privlist) && $rpcenv->check($username, $normpath, $privlist))) {
+       die "no permission ($path, $privs)\n";
+    }
+
+    return { username => $username };
+};
+
+my $create_ticket = sub {
+    my ($rpcenv, $username, $pw_or_ticket) = @_;
+
+    my $ticketuser;
+    if (($ticketuser = PVE::AccessControl::verify_ticket($pw_or_ticket, 1)) &&
+       ($ticketuser eq 'root@pam' || $ticketuser eq $username)) {
+       # valid ticket. Note: root@pam can create tickets for other users
+    } else {
+       $username = PVE::AccessControl::authenticate_user($username, $pw_or_ticket);
+    }
+
+    my $ticket = PVE::AccessControl::assemble_ticket($username);
+    my $csrftoken = PVE::AccessControl::assemble_csrf_prevention_token($username);
+
+    return {
+       ticket => $ticket,
+       username => $username,
+       CSRFPreventionToken => $csrftoken,
+    };
+};
+
 __PACKAGE__->register_method ({
     name => 'create_ticket', 
     path => 'ticket', 
     method => 'POST',
     permissions => { user => 'world' },
     protected => 1, # else we can't access shadow files
-    description => "Create authentication ticket.",
+    description => "Create or verify authentication ticket.",
     parameters => {
        additionalProperties => 0,
        properties => {
@@ -104,14 +149,14 @@ __PACKAGE__->register_method ({
                type => 'string',
            },
            path => {
-               description => "Only create ticket if user have access 'privs' on 'path'",
+               description => "Verify ticket, and check if user have access 'privs' on 'path'",
                type => 'string',
                requires => 'privs',
                optional => 1,
                maxLength => 64,
            },
            privs => { 
-               description => "Only create ticket if user have access 'privs' on 'path'",
+               description => "Verify ticket, and check if user have access 'privs' on 'path'",
                type => 'string' , format => 'pve-priv-list',
                requires => 'path',
                optional => 1,
@@ -122,9 +167,9 @@ __PACKAGE__->register_method ({
     returns => {
        type => "object",
        properties => {
-           ticket => { type => 'string' },
            username => { type => 'string' },
-           CSRFPreventionToken => { type => 'string' },
+           ticket => { type => 'string', optional => 1},
+           CSRFPreventionToken => { type => 'string', optional => 1 },
        }
     },
     code => sub {
@@ -134,47 +179,29 @@ __PACKAGE__->register_method ({
        $username .= "\@$param->{realm}" if $param->{realm};
 
        my $rpcenv = PVE::RPCEnvironment::get();
-       my $clientip = $rpcenv->get_client_ip() || '';
 
-       my $ticket;
-       my $token;
-       eval {
+       my $res;
 
+       eval {
            # test if user exists and is enabled
            $rpcenv->check_user_enabled($username);
 
            if ($param->{path} && $param->{privs}) {
-               my $privs = [ PVE::Tools::split_list($param->{privs}) ];
-               my $path = PVE::AccessControl::normalize_path($param->{path});
-               if (!($path && scalar(@$privs) && $rpcenv->check($username, $path, $privs))) {
-                   die "no permission ($param->{path}, $param->{privs})\n";
-               }
-           }
-
-           my $tmp;
-           if (($tmp = PVE::AccessControl::verify_ticket($param->{password}, 1)) &&
-               ($tmp eq 'root@pam' || $tmp eq $username)) {
-               # got valid ticket
-               # Note: root@pam can create tickets for other users
-               
+               $res = &$verify_auth($rpcenv, $username, $param->{password},
+                                    $param->{path}, $param->{privs});
            } else {
-               $username = PVE::AccessControl::authenticate_user($username, $param->{password});
+               $res = &$create_ticket($rpcenv, $username, $param->{password});
            }
-           $ticket = PVE::AccessControl::assemble_ticket($username);
-           $token = PVE::AccessControl::assemble_csrf_prevention_token($username);
        };
        if (my $err = $@) {
+           my $clientip = $rpcenv->get_client_ip() || '';
            syslog('err', "authentication failure; rhost=$clientip user=$username msg=$err");
            die $err;
        }
 
        PVE::Cluster::log_msg('info', 'root@pam', "successful auth for user '$username'");
 
-       return {
-           ticket => $ticket,
-           username => $username,
-           CSRFPreventionToken => $token,
-       };
+       return $res;
     }});
 
 1;

diff --git a/PVE/AccessControl.pm b/PVE/AccessControl.pm
index b06ca3b2dfe7bfa87db6998d27df58852dd87845..9bb32ef3818e3b6c54f4085730ffcc22972ba1b1 100644 (file)
--- a/PVE/AccessControl.pm
+++ b/PVE/AccessControl.pm
@@ -150,7 +150,7 @@ sub assemble_ticket {
 sub verify_ticket {
     my ($ticket, $noerr) = @_;
 
-    if ($ticket && $ticket =~ m/^(\S+)::([^:\s]+)$/) {
+    if ($ticket && $ticket =~ m/^(PVE:\S+)::([^:\s]+)$/) {
        my $plain = $1;
        my $sig = $2;
 
@@ -175,6 +175,56 @@ sub verify_ticket {
     return undef;
 }
 
+# VNC tickets
+# - they do not contain the username in plain text
+# - they are restricted to a specific resource path (example: '/vms/100')
+sub assemble_vnc_ticket {
+    my ($username, $path) = @_;
+
+    my $rsa_priv = get_privkey();
+
+    my $timestamp = sprintf("%08X", time());
+
+    my $plain = "PVEVNC:$timestamp";
+
+    $path = normalize_path($path);
+
+    my $full = "$plain:$username:$path";
+
+    my $ticket = $plain . "::" . encode_base64($rsa_priv->sign($full), '');
+
+    return $ticket;
+}
+
+sub verify_vnc_ticket {
+    my ($ticket, $username, $path, $noerr) = @_;
+
+    if ($ticket && $ticket =~ m/^(PVEVNC:\S+)::([^:\s]+)$/) {
+       my $plain = $1;
+       my $sig = $2;
+       my $full = "$plain:$username:$path";
+
+       my $rsa_pub = get_pubkey();
+       # Note: sign only match if $username and  $path is correct
+       if ($rsa_pub->verify($full, decode_base64($sig))) {
+           if ($plain =~ m/^PVEVNC:([A-Z0-9]{8})$/) {
+               my $ttime = hex($1);
+
+               my $age = time() - $ttime;
+
+               if (($age > -20) && ($age < 40)) {
+                   return 1;
+               }
+           }
+       }
+    }
+
+    die "permission denied - invalid vnc ticket\n" if !$noerr;
+
+    return undef;
+}
+
+
 sub authenticate_user_shadow {
     my ($userid, $password) = @_;