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/* packet-hdcp.c
* Routines for HDCP dissection
* Copyright 2011, Martin Kaiser <martin@kaiser.cx>
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* 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 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* This dissector is based on the HDCP 2.1 specification.
It supports the most common authentication protocol messages. */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/ptvcursor.h>
#include <epan/expert.h>
static int proto_hdcp = -1;
static module_t *hdcp_module;
static gboolean hdcp_enable_dissector = FALSE;
void proto_reg_handoff_hdcp(void);
static gint ett_hdcp = -1;
static gint ett_hdcp_cert = -1;
static int hf_hdcp_msg_id = -1;
static int hf_hdcp_r_tx = -1;
static int hf_hdcp_repeater = -1;
static int hf_hdcp_cert_rcv_id = -1;
static int hf_hdcp_cert_n = -1;
static int hf_hdcp_cert_e = -1;
static int hf_hdcp_cert_rcv_sig = -1;
static int hf_hdcp_e_kh_km = -1;
static int hf_hdcp_m = -1;
static int hf_hdcp_r_rx = -1;
static int hf_hdcp_h_prime = -1;
static int hf_hdcp_r_n = -1;
static int hf_hdcp_l_prime = -1;
static int hf_hdcp_e_dkey_ks = -1;
static int hf_hdcp_r_iv = -1;
#define ID_AKE_INIT 2
#define ID_AKE_SEND_CERT 3
#define ID_AKE_STORED_KM 5
#define ID_AKE_SEND_RRX 6
#define ID_AKE_SEND_H_PRIME 7
#define ID_LC_INIT 9
#define ID_LC_SEND_L_PRIME 10
#define ID_SKE_SEND_EKS 11
#define ID_MAX 31
#define RCV_ID_LEN 5 /* all lengths are in bytes */
#define N_LEN 128
#define E_LEN 3
#define RCV_SIG_LEN 384
#define CERT_RX_LEN (RCV_ID_LEN + N_LEN + E_LEN + 2 + RCV_SIG_LEN)
static const value_string hdcp_msg_id[] = {
{ ID_AKE_INIT, "AKE_Init" },
{ ID_AKE_SEND_CERT, "AKE_Send_Cert" },
{ ID_AKE_STORED_KM, "AKE_Stored_km" },
{ ID_AKE_SEND_RRX, "AKE_Send_rrx" },
{ ID_AKE_SEND_H_PRIME, "AKE_Send_H_prime" },
{ ID_LC_INIT, "LC_Init" },
{ ID_LC_SEND_L_PRIME, "LC_Send_L_prime" },
{ ID_SKE_SEND_EKS, "SKE_Send_Eks" },
{ 0, NULL }
};
typedef struct _msg_info_t {
guint8 id;
guint16 len; /* number of bytes following initial msg_id field */
} msg_info_t;
static GHashTable *msg_table = NULL;
static const msg_info_t msg_info[] = {
{ ID_AKE_INIT, 8 },
{ ID_AKE_SEND_CERT, 1+CERT_RX_LEN },
{ ID_AKE_STORED_KM, 32 },
{ ID_AKE_SEND_RRX, 8 },
{ ID_AKE_SEND_H_PRIME, 32 },
{ ID_LC_INIT, 8 },
{ ID_LC_SEND_L_PRIME, 32 },
{ ID_SKE_SEND_EKS, 24 }
};
static int
dissect_hdcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
msg_info_t *mi;
proto_item *pi;
proto_tree *hdcp_tree = NULL, *cert_tree = NULL;
guint8 msg_id;
gboolean repeater;
guint16 reserved;
ptvcursor_t *cursor;
/* do the plausibility checks before setting up anything */
msg_id = tvb_get_guint8(tvb, 0);
if (msg_id > ID_MAX)
return 0;
mi = (msg_info_t *)g_hash_table_lookup(msg_table,
GUINT_TO_POINTER((guint)msg_id));
/* 1 -> start after msg_id byte */
if (!mi || mi->len!=tvb_reported_length_remaining(tvb, 1))
return 0;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "HDCP");
col_clear(pinfo->cinfo, COL_INFO);
if (tree) {
pi = proto_tree_add_protocol_format(tree, proto_hdcp,
tvb, 0, tvb_reported_length(tvb), "HDCP");
hdcp_tree = proto_item_add_subtree(pi, ett_hdcp);
}
cursor = ptvcursor_new(hdcp_tree, tvb, 0);
col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
val_to_str(msg_id, hdcp_msg_id, "unknown (0x%x)"));
ptvcursor_add(cursor, hf_hdcp_msg_id, 1, ENC_BIG_ENDIAN);
switch (msg_id) {
case ID_AKE_INIT:
ptvcursor_add(cursor, hf_hdcp_r_tx, 8, ENC_BIG_ENDIAN);
break;
case ID_AKE_SEND_CERT:
repeater = ((tvb_get_guint8(tvb, ptvcursor_current_offset(cursor))
& 0x01) == 0x01);
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "%s",
repeater ? "repeater" : "no repeater");
ptvcursor_add(cursor, hf_hdcp_repeater, 1, ENC_BIG_ENDIAN);
if (hdcp_tree) {
cert_tree = ptvcursor_add_text_with_subtree(cursor, CERT_RX_LEN,
ett_hdcp_cert, "%s", "HDCP Certificate");
}
ptvcursor_add(cursor, hf_hdcp_cert_rcv_id, RCV_ID_LEN, ENC_NA);
ptvcursor_add(cursor, hf_hdcp_cert_n, N_LEN, ENC_NA);
ptvcursor_add(cursor, hf_hdcp_cert_e, E_LEN, ENC_BIG_ENDIAN);
reserved = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
proto_tree_add_text(cert_tree, tvb,
ptvcursor_current_offset(cursor), 2, "reserved bytes");
if (reserved != 0) {
pi = proto_tree_add_text(cert_tree, tvb,
ptvcursor_current_offset(cursor), 2, "invalid value");
expert_add_info_format(pinfo, pi, PI_PROTOCOL, PI_WARN,
"reserved bytes must be set to 0x0");
}
ptvcursor_advance(cursor, 2);
ptvcursor_add(cursor, hf_hdcp_cert_rcv_sig, RCV_SIG_LEN, ENC_NA);
if (cert_tree)
ptvcursor_pop_subtree(cursor);
break;
case ID_AKE_STORED_KM:
ptvcursor_add(cursor, hf_hdcp_e_kh_km, 16, ENC_NA);
ptvcursor_add(cursor, hf_hdcp_m, 16, ENC_NA);
break;
case ID_AKE_SEND_RRX:
ptvcursor_add(cursor, hf_hdcp_r_rx, 8, ENC_BIG_ENDIAN);
break;
case ID_AKE_SEND_H_PRIME:
ptvcursor_add(cursor, hf_hdcp_h_prime, 32, ENC_NA);
break;
case ID_LC_INIT:
ptvcursor_add(cursor, hf_hdcp_r_n, 8, ENC_BIG_ENDIAN);
break;
case ID_LC_SEND_L_PRIME:
ptvcursor_add(cursor, hf_hdcp_l_prime, 32, ENC_NA);
break;
case ID_SKE_SEND_EKS:
ptvcursor_add(cursor, hf_hdcp_e_dkey_ks, 16, ENC_NA);
ptvcursor_add(cursor, hf_hdcp_r_iv, 8, ENC_BIG_ENDIAN);
break;
default:
break;
}
ptvcursor_free(cursor);
return tvb_reported_length(tvb);
}
void
proto_register_hdcp(void)
{
guint i;
static gint *ett[] = {
&ett_hdcp,
&ett_hdcp_cert
};
static hf_register_info hf[] = {
{ &hf_hdcp_msg_id,
{ "Message ID", "hdcp.msg_id", FT_UINT8, BASE_HEX,
VALS(hdcp_msg_id), 0, NULL, HFILL } },
{ &hf_hdcp_r_tx,
{ "r_tx", "hdcp.r_tx", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_repeater,
{ "Repeater", "hdcp.repeater", FT_BOOLEAN, BASE_NONE,
NULL, 0x1, NULL, HFILL } },
{ &hf_hdcp_cert_rcv_id,
{ "Receiver ID", "hdcp.cert.rcv_id", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_cert_n,
{ "Receiver RSA key n", "hdcp.cert.n", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_cert_e,
{ "Receiver RSA key e", "hdcp.cert.e", FT_UINT24, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_cert_rcv_sig,
{ "Receiver signature", "hdcp.cert.rcv_sig", FT_BYTES,
BASE_NONE, NULL, 0, NULL, HFILL } },
{ &hf_hdcp_e_kh_km,
{ "E_kh_km", "hdcp.e_kh_km", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_m,
{ "m", "hdcp.m", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_r_rx,
{ "r_rx", "hdcp.r_rx", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_h_prime,
{ "H'", "hdcp.h_prime", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_r_n,
{ "r_n", "hdcp.r_n", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_l_prime,
{ "L'", "hdcp.l_prime", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_e_dkey_ks,
{ "E_dkey_ks", "hdcp.e_dkey_ks", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp_r_iv,
{ "r_iv", "hdcp.r_iv", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } }
};
msg_table = g_hash_table_new(g_direct_hash, g_direct_equal);
for(i=0; i<array_length(msg_info); i++) {
g_hash_table_insert(msg_table,
GUINT_TO_POINTER((guint)msg_info[i].id),
(gpointer)(&msg_info[i]));
}
proto_hdcp = proto_register_protocol(
"High bandwidth Digital Content Protection", "HDCP", "hdcp");
hdcp_module = prefs_register_protocol(proto_hdcp, proto_reg_handoff_hdcp);
prefs_register_bool_preference(hdcp_module, "enable", "Enable dissector",
"Enable this dissector (default is false)",
&hdcp_enable_dissector);
proto_register_field_array(proto_hdcp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_hdcp(void)
{
static gboolean prefs_initialized = FALSE;
if (!prefs_initialized) {
heur_dissector_add ("tcp", dissect_hdcp, proto_hdcp);
prefs_initialized = TRUE;
}
proto_set_decoding(proto_hdcp, hdcp_enable_dissector);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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