aboutsummaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-hdcp2.c
blob: bc8a131f4f60cf61d70f8b93ebb00651dd49423a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
/* 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(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, 0x01, 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, 0x01, 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(proto_hdcp2, proto_reg_handoff_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  -  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:
 */