/* 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;

static int ett_hdcp2;

static int ett_hdcp2_cert;

static int hf_hdcp2_msg_id;

static int hf_hdcp2_r_tx;

static int hf_hdcp2_repeater;

static int hf_hdcp2_cert_rcv_id;

static int hf_hdcp2_cert_n;

static int hf_hdcp2_cert_e;

static int hf_hdcp2_cert_rcv_sig;

static int hf_hdcp2_e_kpub_km;

static int hf_hdcp2_e_kh_km;

static int hf_hdcp2_m;

static int hf_hdcp2_r_rx;

static int hf_hdcp2_h_prime;

static int hf_hdcp2_r_n;

static int hf_hdcp2_l_prime;

static int hf_hdcp2_e_dkey_ks;

static int hf_hdcp2_r_iv;

static int hf_hdcp2_reserved;

static int hf_hdcp2_tx_length;

static int hf_hdcp2_tx_version;

static int hf_hdcp2_tx_loc_precompute;

static int hf_hdcp2_rx_length;

static int hf_hdcp2_rx_version;

static int hf_hdcp2_rx_loc_precompute;

static expert_field ei_hdcp2_reserved_0;

static expert_field ei_hdcp2_version_not_2;

static expert_field ei_hdcp2_length;

#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 {

    uint8_t id;

    uint16_t len;  /* number of bytes following initial msg_id field */

} msg_info_t;

static wmem_map_t *msg_table;

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;

    uint8_t msg_id, version;

    bool repeater, loc_precomp;

    uint16_t reserved, length;

    ptvcursor_t *cursor;

    /* do the plausibility checks before setting up anything */

    /* make sure that tvb_get_uint8() won't throw an exception */

    if (tvb_captured_length(tvb) < 1)

        return 0;

    msg_id = tvb_get_uint8(tvb, 0);

    if (msg_id > ID_MAX)

        return 0;

    mi = (msg_info_t *)wmem_map_lookup(msg_table,

            GUINT_TO_POINTER((unsigned)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(pinfo->pool, 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_uint8(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_uint8(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_uint8(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);

}

static bool

dissect_hdcp2_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

    return dissect_hdcp2(tvb, pinfo, tree, data) > 0;

}

void

proto_register_hdcp2(void)

{

    unsigned 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 int *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((unsigned)msg_info[i].id),

                (void *)(&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 bool prefs_initialized = false;

    if (!prefs_initialized) {

        heur_dissector_add ("tcp", dissect_hdcp2_heur, "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:

 */