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/*
* Copyright (C) 2010-2011 Robert Ancell.
* Author: Robert Ancell <robert.ancell@canonical.com>
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version. See http://www.gnu.org/copyleft/gpl.html the full text of the
* license.
*/
#include <string.h>
#include "xdmcp-protocol.h"
typedef struct
{
const guchar *data;
guint16 remaining;
gboolean overflow;
} PacketReader;
static guint8
read_card8 (PacketReader *reader)
{
guint8 value;
if (reader->remaining < 1)
{
reader->overflow = TRUE;
return 0;
}
value = reader->data[0];
reader->data++;
reader->remaining--;
return value;
}
static guint16
read_card16 (PacketReader *reader)
{
return read_card8 (reader) << 8 | read_card8 (reader);
}
static guint32
read_card32 (PacketReader *reader)
{
return read_card8 (reader) << 24 | read_card8 (reader) << 16 | read_card8 (reader) << 8 | read_card8 (reader);
}
static void
read_data (PacketReader *reader, XDMCPData *data)
{
guint16 i;
data->length = read_card16 (reader);
data->data = g_malloc (sizeof (guchar) * data->length);
for (i = 0; i < data->length; i++)
data->data[i] = read_card8 (reader);
}
static gchar *
read_string (PacketReader *reader)
{
guint16 length, i;
gchar *string;
length = read_card16 (reader);
string = g_malloc (sizeof (gchar) * (length + 1));
for (i = 0; i < length; i++)
string[i] = (gchar) read_card8 (reader);
string[i] = '\0';
return string;
}
static gchar **
read_string_array (PacketReader *reader)
{
guint8 n_strings, i;
gchar **strings;
n_strings = read_card8 (reader);
strings = g_malloc (sizeof (gchar *) * (n_strings + 1));
for (i = 0; i < n_strings; i++)
strings[i] = read_string (reader);
strings[i] = NULL;
return strings;
}
typedef struct
{
guchar *data;
guint16 remaining;
gboolean overflow;
} PacketWriter;
static void
write_card8 (PacketWriter *writer, guint8 value)
{
if (writer->remaining < 1)
{
writer->overflow = TRUE;
return;
}
writer->data[0] = value;
writer->data++;
writer->remaining--;
}
static void
write_card16 (PacketWriter *writer, guint16 value)
{
write_card8 (writer, value >> 8);
write_card8 (writer, value & 0xFF);
}
static void
write_card32 (PacketWriter *writer, guint16 value)
{
write_card8 (writer, (value >> 24) & 0xFF);
write_card8 (writer, (value >> 16) & 0xFF);
write_card8 (writer, (value >> 8) & 0xFF);
write_card8 (writer, value & 0xFF);
}
static void
write_data (PacketWriter *writer, const XDMCPData *value)
{
guint16 i;
write_card16 (writer, value->length);
for (i = 0; i < value->length; i++)
write_card8 (writer, value->data[i]);
}
static void
write_string (PacketWriter *writer, const gchar *value)
{
const gchar *c;
write_card16 (writer, strlen (value));
for (c = value; *c; c++)
write_card8 (writer, *c);
}
static void
write_string_array (PacketWriter *writer, gchar **values)
{
gchar **value;
write_card8 (writer, g_strv_length (values));
for (value = values; *value; value++)
write_string (writer, *value);
}
XDMCPPacket *
xdmcp_packet_alloc (XDMCPOpcode opcode)
{
XDMCPPacket *packet;
packet = g_malloc0 (sizeof (XDMCPPacket));
packet->opcode = opcode;
return packet;
}
XDMCPPacket *
xdmcp_packet_decode (const guchar *data, gsize data_length)
{
XDMCPPacket *packet;
guint16 version, opcode, length;
PacketReader reader;
int i;
gboolean failed = FALSE;
reader.data = data;
reader.remaining = data_length;
reader.overflow = FALSE;
version = read_card16 (&reader);
opcode = read_card16 (&reader);
length = read_card16 (&reader);
if (reader.overflow)
{
g_warning ("Ignoring short packet"); // FIXME: Use GError
return NULL;
}
if (version != XDMCP_VERSION)
{
g_warning ("Ignoring packet from unknown version %d", version);
return NULL;
}
if (length != reader.remaining)
{
g_warning ("Ignoring packet of wrong length");
return NULL;
}
packet = xdmcp_packet_alloc (opcode);
switch (packet->opcode)
{
case XDMCP_BroadcastQuery:
case XDMCP_Query:
case XDMCP_IndirectQuery:
packet->Query.authentication_names = read_string_array (&reader);
break;
case XDMCP_ForwardQuery:
packet->ForwardQuery.client_address = read_string (&reader);
packet->ForwardQuery.client_port = read_string (&reader);
packet->ForwardQuery.authentication_names = read_string_array (&reader);
break;
case XDMCP_Willing:
packet->Willing.authentication_name = read_string (&reader);
packet->Willing.hostname = read_string (&reader);
packet->Willing.status = read_string (&reader);
break;
case XDMCP_Unwilling:
packet->Unwilling.hostname = read_string (&reader);
packet->Unwilling.status = read_string (&reader);
break;
case XDMCP_Request:
packet->Request.display_number = read_card16 (&reader);
packet->Request.n_connections = read_card8 (&reader);
packet->Request.connections = g_malloc (sizeof (XDMCPConnection) * packet->Request.n_connections);
for (i = 0; i < packet->Request.n_connections; i++)
packet->Request.connections[i].type = read_card16 (&reader);
if (read_card8 (&reader) != packet->Request.n_connections)
{
g_warning ("Number of connection types does not match number of connection addresses");
failed = TRUE;
}
for (i = 0; i < packet->Request.n_connections; i++)
read_data (&reader, &packet->Request.connections[i].address);
packet->Request.authentication_name = read_string (&reader);
read_data (&reader, &packet->Request.authentication_data);
packet->Request.authorization_names = read_string_array (&reader);
packet->Request.manufacturer_display_id = read_string (&reader);
break;
case XDMCP_Accept:
packet->Accept.session_id = read_card32 (&reader);
packet->Accept.authentication_name = read_string (&reader);
read_data (&reader, &packet->Accept.authentication_data);
packet->Accept.authorization_name = read_string (&reader);
read_data (&reader, &packet->Accept.authorization_data);
break;
case XDMCP_Decline:
packet->Decline.status = read_string (&reader);
packet->Decline.authentication_name = read_string (&reader);
read_data (&reader, &packet->Decline.authentication_data);
break;
case XDMCP_Manage:
packet->Manage.session_id = read_card32 (&reader);
packet->Manage.display_number = read_card16 (&reader);
packet->Manage.display_class = read_string (&reader);
break;
case XDMCP_Refuse:
packet->Refuse.session_id = read_card32 (&reader);
break;
case XDMCP_Failed:
packet->Failed.session_id = read_card32 (&reader);
packet->Failed.status = read_string (&reader);
break;
case XDMCP_KeepAlive:
packet->KeepAlive.display_number = read_card16 (&reader);
packet->KeepAlive.session_id = read_card32 (&reader);
break;
case XDMCP_Alive:
packet->Alive.session_running = read_card8 (&reader) == 0 ? FALSE : TRUE;
packet->Alive.session_id = read_card32 (&reader);
break;
default:
g_warning ("Unable to encode unknown opcode %d", packet->opcode);
failed = TRUE;
break;
}
if (!failed)
{
if (reader.overflow)
{
g_warning ("Short packet received");
failed = TRUE;
}
else if (reader.remaining != 0)
{
g_warning ("Extra data on end of message");
failed = TRUE;
}
}
if (failed)
{
xdmcp_packet_free (packet);
return NULL;
}
return packet;
}
gssize
xdmcp_packet_encode (XDMCPPacket *packet, guchar *data, gsize max_length)
{
guint16 length;
PacketWriter writer;
int i;
if (max_length < 6)
return -1;
writer.data = data + 6;
writer.remaining = max_length - 6;
writer.overflow = FALSE;
switch (packet->opcode)
{
case XDMCP_BroadcastQuery:
case XDMCP_Query:
case XDMCP_IndirectQuery:
write_string_array (&writer, packet->Query.authentication_names);
break;
case XDMCP_ForwardQuery:
write_string (&writer, packet->ForwardQuery.client_address);
write_string (&writer, packet->ForwardQuery.client_port);
write_string_array (&writer, packet->ForwardQuery.authentication_names);
break;
case XDMCP_Willing:
write_string (&writer, packet->Willing.authentication_name);
write_string (&writer, packet->Willing.hostname);
write_string (&writer, packet->Willing.status);
break;
case XDMCP_Unwilling:
write_string (&writer, packet->Unwilling.hostname);
write_string (&writer, packet->Unwilling.status);
break;
case XDMCP_Request:
write_card16 (&writer, packet->Request.display_number);
write_card8 (&writer, packet->Request.n_connections);
for (i = 0; i < packet->Request.n_connections; i++)
write_card16 (&writer, packet->Request.connections[i].type);
write_card8 (&writer, packet->Request.n_connections);
for (i = 0; i < packet->Request.n_connections; i++)
write_data (&writer, &packet->Request.connections[i].address);
write_string (&writer, packet->Request.authentication_name);
write_data (&writer, &packet->Request.authentication_data);
write_string_array (&writer, packet->Request.authorization_names);
write_string (&writer, packet->Request.manufacturer_display_id);
break;
case XDMCP_Accept:
write_card32 (&writer, packet->Accept.session_id);
write_string (&writer, packet->Accept.authentication_name);
write_data (&writer, &packet->Accept.authentication_data);
write_string (&writer, packet->Accept.authorization_name);
write_data (&writer, &packet->Accept.authorization_data);
break;
case XDMCP_Decline:
write_string (&writer, packet->Decline.status);
write_string (&writer, packet->Decline.authentication_name);
write_data (&writer, &packet->Decline.authentication_data);
break;
case XDMCP_Manage:
write_card32 (&writer, packet->Manage.session_id);
write_card16 (&writer, packet->Manage.display_number);
write_string (&writer, packet->Manage.display_class);
break;
case XDMCP_Refuse:
write_card32 (&writer, packet->Refuse.session_id);
break;
case XDMCP_Failed:
write_card32 (&writer, packet->Failed.session_id);
write_string (&writer, packet->Failed.status);
break;
case XDMCP_KeepAlive:
write_card16 (&writer, packet->KeepAlive.display_number);
write_card32 (&writer, packet->KeepAlive.session_id);
break;
case XDMCP_Alive:
write_card8 (&writer, packet->Alive.session_running ? 1 : 0);
write_card32 (&writer, packet->Alive.session_id);
break;
}
length = max_length - 6 - writer.remaining;
/* Write header */
writer.data = data;
writer.remaining = 6;
writer.overflow = FALSE;
write_card16(&writer, XDMCP_VERSION);
write_card16(&writer, packet->opcode);
write_card16(&writer, length);
if (writer.overflow)
{
g_warning ("Overflow writing response");
return -1;
}
return length + 6;
}
static gchar *
data_tostring (XDMCPData *data)
{
GString *s;
guint16 i;
gchar *string;
s = g_string_new ("");
for (i = 0; i < data->length; i++)
g_string_append_printf (s, "%02X", data->data[i]);
string = s->str;
g_string_free (s, FALSE);
return string;
}
static gchar *
string_list_tostring (gchar **strings)
{
GString *s;
gchar *string;
gchar **i;
s = g_string_new ("");
for (i = strings; *i; i++)
{
if (i != strings)
g_string_append (s, " ");
g_string_append_printf (s, "'%s'", *i);
}
string = s->str;
g_string_free (s, FALSE);
return string;
}
gchar *
xdmcp_packet_tostring (XDMCPPacket *packet)
{
gchar *string, *t, *t2;
gint i;
GString *t3;
switch (packet->opcode)
{
case XDMCP_BroadcastQuery:
t = string_list_tostring (packet->Query.authentication_names);
string = g_strdup_printf ("BroadcastQuery(authentication_names=[%s])", t);
g_free (t);
return string;
case XDMCP_Query:
t = string_list_tostring (packet->Query.authentication_names);
string = g_strdup_printf ("Query(authentication_names=[%s])", t);
g_free (t);
return string;
case XDMCP_IndirectQuery:
t = string_list_tostring (packet->Query.authentication_names);
string = g_strdup_printf ("IndirectQuery(authentication_names=[%s])", t);
g_free (t);
return string;
case XDMCP_ForwardQuery:
t = string_list_tostring (packet->ForwardQuery.authentication_names);
string = g_strdup_printf ("ForwardQuery(client_address='%s' client_port='%s' authentication_names=[%s])",
packet->ForwardQuery.client_address, packet->ForwardQuery.client_port, t);
g_free (t);
return string;
case XDMCP_Willing:
return g_strdup_printf ("Willing(authentication_name='%s' hostname='%s' status='%s')",
packet->Willing.authentication_name, packet->Willing.hostname, packet->Willing.status);
case XDMCP_Unwilling:
return g_strdup_printf ("Unwilling(hostname='%s' status='%s')",
packet->Unwilling.hostname, packet->Unwilling.status);
case XDMCP_Request:
t = string_list_tostring (packet->Request.authorization_names);
t2 = data_tostring (&packet->Request.authentication_data);
t3 = g_string_new ("");
for (i = 0; i < packet->Request.n_connections; i++)
{
gchar *t4;
if (i != 0)
g_string_append (t3, " ");
t4 = data_tostring (&packet->Request.connections[i].address);
g_string_append_printf (t3, "(%d, %s)", packet->Request.connections[i].type, t4);
g_free (t4);
}
string = g_strdup_printf ("Request(display_number=%d connections=[%s] authentication_name='%s' authentication_data=%s authorization_names=[%s] manufacturer_display_id='%s')",
packet->Request.display_number, t3->str, packet->Request.authentication_name, t2,
t, packet->Request.manufacturer_display_id);
g_free (t);
g_free (t2);
g_string_free (t3, TRUE);
return string;
case XDMCP_Accept:
t = data_tostring (&packet->Accept.authentication_data);
t2 = data_tostring (&packet->Accept.authorization_data);
string = g_strdup_printf ("Accept(session_id=%d authentication_name='%s' authentication_data=%s authorization_name='%s' authorization_data=%s)",
packet->Accept.session_id, packet->Accept.authentication_name, t,
packet->Accept.authorization_name, t2);
g_free (t);
g_free (t2);
return string;
case XDMCP_Decline:
t = data_tostring (&packet->Decline.authentication_data);
string = g_strdup_printf ("Decline(status='%s' authentication_name='%s' authentication_data=%s)",
packet->Decline.status, packet->Decline.authentication_name, t);
g_free (t);
return string;
case XDMCP_Manage:
return g_strdup_printf ("Manage(session_id=%d display_number=%d display_class='%s')",
packet->Manage.session_id, packet->Manage.display_number, packet->Manage.display_class);
case XDMCP_Refuse:
return g_strdup_printf ("Refuse(session_id=%d)", packet->Refuse.session_id);
case XDMCP_Failed:
return g_strdup_printf ("Failed(session_id=%d status='%s')", packet->Failed.session_id, packet->Failed.status);
case XDMCP_KeepAlive:
return g_strdup_printf ("KeepAlive(display_number=%d session_id=%d)",
packet->KeepAlive.display_number, packet->KeepAlive.session_id);
case XDMCP_Alive:
return g_strdup_printf ("Alive(session_running=%s session_id=%d)",
packet->Alive.session_running ? "true" : "false", packet->Alive.session_id);
default:
return g_strdup_printf ("XDMCPPacket(opcode=%d)", packet->opcode);
}
}
void
xdmcp_packet_free (XDMCPPacket *packet)
{
gint i;
if (packet == NULL)
return;
switch (packet->opcode)
{
case XDMCP_BroadcastQuery:
case XDMCP_Query:
case XDMCP_IndirectQuery:
g_strfreev (packet->Query.authentication_names);
break;
case XDMCP_ForwardQuery:
g_free (packet->ForwardQuery.client_address);
g_free (packet->ForwardQuery.client_port);
g_strfreev (packet->ForwardQuery.authentication_names);
break;
case XDMCP_Willing:
g_free (packet->Willing.authentication_name);
g_free (packet->Willing.hostname);
g_free (packet->Willing.status);
break;
case XDMCP_Unwilling:
g_free (packet->Unwilling.hostname);
g_free (packet->Unwilling.status);
break;
case XDMCP_Request:
for (i = 0; i < packet->Request.n_connections; i++)
g_free (packet->Request.connections[i].address.data);
g_free (packet->Request.connections);
g_free (packet->Request.authentication_name);
g_free (packet->Request.authentication_data.data);
g_strfreev (packet->Request.authorization_names);
g_free (packet->Request.manufacturer_display_id);
break;
case XDMCP_Accept:
g_free (packet->Accept.authentication_name);
g_free (packet->Accept.authentication_data.data);
g_free (packet->Accept.authorization_name);
g_free (packet->Accept.authorization_data.data);
break;
case XDMCP_Decline:
g_free (packet->Decline.status);
g_free (packet->Decline.authentication_name);
g_free (packet->Decline.authentication_data.data);
break;
case XDMCP_Manage:
g_free (packet->Manage.display_class);
break;
case XDMCP_Refuse:
break;
case XDMCP_Failed:
g_free (packet->Failed.status);
break;
case XDMCP_KeepAlive:
break;
case XDMCP_Alive:
break;
}
g_free (packet);
}
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