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/* packet-hdcp2.c
* Routines for HDCP2 dissection
* Copyright 2011-2012, Martin Kaiser <martin@kaiser.cx>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
* This dissector supports HDCP 2.x over TCP. For now, only the
* authentication protocol messages are supported.
*
* The specification of version 2 of the protocol can be found at
* http://www.digital-cp.com/files/static_page_files/DABB540C-1A4B-B294-D0008CB2D348FA19/HDCP Interface Independent Adaptation Specification Rev2_1.pdf
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/ptvcursor.h>
#include <epan/expert.h>
void proto_register_hdcp2(void);
void proto_reg_handoff_hdcp2(void);
static int proto_hdcp2 = -1;
static gint ett_hdcp2 = -1;
static gint ett_hdcp2_cert = -1;
static int hf_hdcp2_msg_id = -1;
static int hf_hdcp2_r_tx = -1;
static int hf_hdcp2_repeater = -1;
static int hf_hdcp2_cert_rcv_id = -1;
static int hf_hdcp2_cert_n = -1;
static int hf_hdcp2_cert_e = -1;
static int hf_hdcp2_cert_rcv_sig = -1;
static int hf_hdcp2_e_kpub_km = -1;
static int hf_hdcp2_e_kh_km = -1;
static int hf_hdcp2_m = -1;
static int hf_hdcp2_r_rx = -1;
static int hf_hdcp2_h_prime = -1;
static int hf_hdcp2_r_n = -1;
static int hf_hdcp2_l_prime = -1;
static int hf_hdcp2_e_dkey_ks = -1;
static int hf_hdcp2_r_iv = -1;
static int hf_hdcp2_reserved = -1;
static int hf_hdcp2_tx_length = -1;
static int hf_hdcp2_tx_version = -1;
static int hf_hdcp2_tx_loc_precompute = -1;
static int hf_hdcp2_rx_length = -1;
static int hf_hdcp2_rx_version = -1;
static int hf_hdcp2_rx_loc_precompute = -1;
static expert_field ei_hdcp2_reserved_0 = EI_INIT;
static expert_field ei_hdcp2_version_not_2 = EI_INIT;
static expert_field ei_hdcp2_length = EI_INIT;
#define ID_AKE_INIT 2
#define ID_AKE_SEND_CERT 3
#define ID_AKE_NO_STORED_KM 4
#define ID_AKE_STORED_KM 5
#define ID_AKE_SEND_RRX 6
#define ID_AKE_SEND_H_PRIME 7
#define ID_AKE_SEND_PAIRING_INFO 8
#define ID_LC_INIT 9
#define ID_LC_SEND_L_PRIME 10
#define ID_SKE_SEND_EKS 11
#define ID_AKE_TRANSMITTER_INFO 19
#define ID_AKE_RECEIVER_INFO 20
#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 MSG_FIELD_TRANSMITTER_INFO_LENGTH 6
#define MSG_FIELD_RECEIVER_INFO_LENGTH 6
#define CERT_RX_LEN (RCV_ID_LEN + N_LEN + E_LEN + 2 + RCV_SIG_LEN)
static const value_string hdcp2_msg_id[] = {
{ ID_AKE_INIT, "AKE_Init" },
{ ID_AKE_TRANSMITTER_INFO, "AKE_Transmitter_Info" },
{ ID_AKE_SEND_CERT, "AKE_Send_Cert" },
{ ID_AKE_RECEIVER_INFO, "AKE_Receiver_Info" },
{ ID_AKE_NO_STORED_KM, "AKE_No_Stored_km" },
{ ID_AKE_STORED_KM, "AKE_Stored_km" },
{ ID_AKE_SEND_RRX, "AKE_Send_rrx" },
{ ID_AKE_SEND_H_PRIME, "AKE_Send_H_prime" },
{ ID_AKE_SEND_PAIRING_INFO, "AKE_Send_Pairing_Info" },
{ 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 wmem_map_t *msg_table = NULL;
static const msg_info_t msg_info[] = {
{ ID_AKE_INIT, 8 },
{ ID_AKE_TRANSMITTER_INFO, 5 },
{ ID_AKE_SEND_CERT, 1+CERT_RX_LEN },
{ ID_AKE_RECEIVER_INFO, 5 },
{ ID_AKE_NO_STORED_KM, 128 },
{ ID_AKE_STORED_KM, 32 },
{ ID_AKE_SEND_RRX, 8 },
{ ID_AKE_SEND_H_PRIME, 32 },
{ ID_AKE_SEND_PAIRING_INFO, 16 },
{ ID_LC_INIT, 8 },
{ ID_LC_SEND_L_PRIME, 32 },
{ ID_SKE_SEND_EKS, 24 }
};
static int
dissect_hdcp2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
msg_info_t *mi;
proto_item *pi;
proto_tree *hdcp_tree, *cert_tree;
guint8 msg_id, version;
gboolean repeater, loc_precomp;
guint16 reserved, length;
ptvcursor_t *cursor;
/* do the plausibility checks before setting up anything */
/* make sure that tvb_get_guint8() won't throw an exception */
if (tvb_captured_length(tvb) < 1)
return 0;
msg_id = tvb_get_guint8(tvb, 0);
if (msg_id > ID_MAX)
return 0;
mi = (msg_info_t *)wmem_map_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, "HDCP2");
col_clear(pinfo->cinfo, COL_INFO);
pi = proto_tree_add_protocol_format(tree, proto_hdcp2,
tvb, 0, tvb_reported_length(tvb), "HDCP2");
hdcp_tree = proto_item_add_subtree(pi, ett_hdcp2);
cursor = ptvcursor_new(pinfo->pool, hdcp_tree, tvb, 0);
col_append_str(pinfo->cinfo, COL_INFO,
val_to_str(msg_id, hdcp2_msg_id, "unknown (0x%x)"));
ptvcursor_add(cursor, hf_hdcp2_msg_id, 1, ENC_BIG_ENDIAN);
switch (msg_id) {
case ID_AKE_INIT:
ptvcursor_add(cursor, hf_hdcp2_r_tx, 8, ENC_BIG_ENDIAN);
break;
case ID_AKE_TRANSMITTER_INFO:
length = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
pi = proto_tree_add_item(ptvcursor_tree(cursor),
hf_hdcp2_tx_length, tvb, ptvcursor_current_offset(cursor),
2, ENC_BIG_ENDIAN);
if (length < MSG_FIELD_TRANSMITTER_INFO_LENGTH) {
expert_add_info_format(pinfo, pi, &ei_hdcp2_length,
"Length must be at least %d",
MSG_FIELD_TRANSMITTER_INFO_LENGTH);
}
ptvcursor_advance(cursor, 2);
version = tvb_get_guint8(tvb, ptvcursor_current_offset(cursor));
pi = proto_tree_add_item(ptvcursor_tree(cursor),
hf_hdcp2_tx_version, tvb, ptvcursor_current_offset(cursor),
1, ENC_BIG_ENDIAN);
if (version != 2) {
expert_add_info(pinfo, pi, &ei_hdcp2_version_not_2);
}
ptvcursor_advance(cursor, 1);
loc_precomp = ((tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor))
& 0x01) == 0x01);
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL,
loc_precomp ? "locality precompute" : "no locality precompute");
ptvcursor_add(cursor, hf_hdcp2_tx_loc_precompute, 2, ENC_BIG_ENDIAN);
break;
case ID_AKE_SEND_CERT:
repeater = ((tvb_get_guint8(tvb, ptvcursor_current_offset(cursor))
& 0x01) == 0x01);
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL,
repeater ? "repeater" : "no repeater");
ptvcursor_add(cursor, hf_hdcp2_repeater, 1, ENC_BIG_ENDIAN);
cert_tree = ptvcursor_add_text_with_subtree(cursor, CERT_RX_LEN,
ett_hdcp2_cert, "%s", "HDCP2 Certificate");
ptvcursor_add(cursor, hf_hdcp2_cert_rcv_id, RCV_ID_LEN, ENC_NA);
ptvcursor_add(cursor, hf_hdcp2_cert_n, N_LEN, ENC_NA);
ptvcursor_add(cursor, hf_hdcp2_cert_e, E_LEN, ENC_BIG_ENDIAN);
reserved = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
pi = proto_tree_add_item(cert_tree, hf_hdcp2_reserved, tvb,
ptvcursor_current_offset(cursor), 2, ENC_BIG_ENDIAN);
if ((reserved & 0xEFFF) != 0) {
expert_add_info(pinfo, pi, &ei_hdcp2_reserved_0);
}
ptvcursor_advance(cursor, 2);
ptvcursor_add(cursor, hf_hdcp2_cert_rcv_sig, RCV_SIG_LEN, ENC_NA);
ptvcursor_pop_subtree(cursor);
break;
case ID_AKE_RECEIVER_INFO:
length = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
pi = proto_tree_add_item(ptvcursor_tree(cursor),
hf_hdcp2_rx_length, tvb, ptvcursor_current_offset(cursor),
2, ENC_BIG_ENDIAN);
if (length < MSG_FIELD_RECEIVER_INFO_LENGTH) {
expert_add_info_format(pinfo, pi, &ei_hdcp2_length,
"Length must be at least %d",
MSG_FIELD_RECEIVER_INFO_LENGTH);
}
ptvcursor_advance(cursor, 2);
version = tvb_get_guint8(tvb, ptvcursor_current_offset(cursor));
pi = proto_tree_add_item(ptvcursor_tree(cursor),
hf_hdcp2_rx_version, tvb, ptvcursor_current_offset(cursor),
1, ENC_BIG_ENDIAN);
if (version != 2) {
expert_add_info(pinfo, pi, &ei_hdcp2_version_not_2);
}
ptvcursor_advance(cursor, 1);
loc_precomp = ((tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor))
& 0x01) == 0x01);
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL,
loc_precomp ? "locality precompute" : "no locality precompute");
ptvcursor_add(cursor, hf_hdcp2_rx_loc_precompute, 2, ENC_BIG_ENDIAN);
break;
case ID_AKE_NO_STORED_KM:
ptvcursor_add(cursor, hf_hdcp2_e_kpub_km, 128, ENC_NA);
break;
case ID_AKE_STORED_KM:
ptvcursor_add(cursor, hf_hdcp2_e_kh_km, 16, ENC_NA);
ptvcursor_add(cursor, hf_hdcp2_m, 16, ENC_NA);
break;
case ID_AKE_SEND_RRX:
ptvcursor_add(cursor, hf_hdcp2_r_rx, 8, ENC_BIG_ENDIAN);
break;
case ID_AKE_SEND_H_PRIME:
ptvcursor_add(cursor, hf_hdcp2_h_prime, 32, ENC_NA);
break;
case ID_AKE_SEND_PAIRING_INFO:
ptvcursor_add(cursor, hf_hdcp2_e_kh_km, 16, ENC_NA);
break;
case ID_LC_INIT:
ptvcursor_add(cursor, hf_hdcp2_r_n, 8, ENC_BIG_ENDIAN);
break;
case ID_LC_SEND_L_PRIME:
ptvcursor_add(cursor, hf_hdcp2_l_prime, 32, ENC_NA);
break;
case ID_SKE_SEND_EKS:
ptvcursor_add(cursor, hf_hdcp2_e_dkey_ks, 16, ENC_NA);
ptvcursor_add(cursor, hf_hdcp2_r_iv, 8, ENC_BIG_ENDIAN);
break;
default:
break;
}
ptvcursor_free(cursor);
return tvb_reported_length(tvb);
}
void
proto_register_hdcp2(void)
{
guint i;
static hf_register_info hf[] = {
{ &hf_hdcp2_msg_id,
{ "Message ID", "hdcp2.msg_id", FT_UINT8, BASE_HEX,
VALS(hdcp2_msg_id), 0, NULL, HFILL } },
{ &hf_hdcp2_r_tx,
{ "r_tx", "hdcp2.r_tx", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_repeater,
{ "Repeater", "hdcp2.repeater", FT_BOOLEAN, 8,
NULL, 0x1, NULL, HFILL } },
{ &hf_hdcp2_cert_rcv_id,
{ "Receiver ID", "hdcp2.cert.rcv_id", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_cert_n,
{ "Receiver RSA key n", "hdcp2.cert.n", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_cert_e,
{ "Receiver RSA key e", "hdcp2.cert.e", FT_UINT24, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_cert_rcv_sig,
{ "Receiver signature", "hdcp2.cert.rcv_sig", FT_BYTES,
BASE_NONE, NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_e_kpub_km,
{ "E_kpub_km", "hdcp2.e_kpub_km", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_e_kh_km,
{ "E_kh_km", "hdcp2.e_kh_km", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_m,
{ "m", "hdcp2.m", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_r_rx,
{ "r_rx", "hdcp2.r_rx", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_h_prime,
{ "H'", "hdcp2.h_prime", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_r_n,
{ "r_n", "hdcp2.r_n", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_l_prime,
{ "L'", "hdcp2.l_prime", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_e_dkey_ks,
{ "E_dkey_ks", "hdcp2.e_dkey_ks", FT_BYTES, BASE_NONE,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_r_iv,
{ "r_iv", "hdcp2.r_iv", FT_UINT64, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_reserved,
{ "Reserved", "hdcp2.reserved", FT_UINT16, BASE_HEX,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_tx_length,
{ "LENGTH", "hdcp2.txinf_len", FT_UINT16, BASE_DEC,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_tx_version,
{ "VERSION", "hdcp2.txinf_ver", FT_UINT8, BASE_DEC,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_tx_loc_precompute,
{ "Locality Precompute", "hdcp2.txinf_cap", FT_BOOLEAN, 16,
NULL, 0x0001, NULL, HFILL } },
{ &hf_hdcp2_rx_length,
{ "LENGTH", "hdcp2.rxinf_len", FT_UINT16, BASE_DEC,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_rx_version,
{ "VERSION", "hdcp2.rxinf_ver", FT_UINT8, BASE_DEC,
NULL, 0, NULL, HFILL } },
{ &hf_hdcp2_rx_loc_precompute,
{ "Locality Precompute", "hdcp2.rxinf_cap", FT_BOOLEAN, 16,
NULL, 0x0001, NULL, HFILL } },
};
static gint *ett[] = {
&ett_hdcp2,
&ett_hdcp2_cert,
};
static ei_register_info ei[] = {
{ &ei_hdcp2_reserved_0, { "hdcp2.reserved.not0", PI_PROTOCOL, PI_WARN, "reserved bytes must be set to 0x0", EXPFILL }},
{ &ei_hdcp2_version_not_2, { "hdcp2.version.not2", PI_PROTOCOL, PI_WARN, "version must be set to 0x2", EXPFILL }},
{ &ei_hdcp2_length, { "hdcp2.length.invalid", PI_PROTOCOL, PI_WARN, "Invalid length", EXPFILL }},
};
module_t *hdcp2_module;
expert_module_t* expert_hdcp2;
msg_table = wmem_map_new(wmem_epan_scope(), g_direct_hash, g_direct_equal);
for(i=0; i<array_length(msg_info); i++) {
wmem_map_insert(msg_table,
GUINT_TO_POINTER((guint)msg_info[i].id),
(gpointer)(&msg_info[i]));
}
proto_hdcp2 = proto_register_protocol("High bandwidth Digital Content Protection version 2", "HDCP2", "hdcp2");
hdcp2_module = prefs_register_protocol_obsolete(proto_hdcp2);
prefs_register_obsolete_preference(hdcp2_module, "enable");
proto_register_field_array(proto_hdcp2, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_hdcp2 = expert_register_protocol(proto_hdcp2);
expert_register_field_array(expert_hdcp2, ei, array_length(ei));
register_dissector("hdcp2", dissect_hdcp2, proto_hdcp2);
}
void
proto_reg_handoff_hdcp2(void)
{
static gboolean prefs_initialized = FALSE;
if (!prefs_initialized) {
heur_dissector_add ("tcp", dissect_hdcp2, "HDCP2 over TCP", "hdcp2_tcp", proto_hdcp2, HEURISTIC_DISABLE);
prefs_initialized = TRUE;
}
}
/*
* Editor modelines - https://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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