aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/oma.c
blob: 9e98202e4f3862efc18fce122bf1641d7d8e1773 (plain) (blame)
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
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
/*
 * Sony OpenMG (OMA) demuxer
 *
 * Copyright (c) 2008 Maxim Poliakovski
 *               2008 Benjamin Larsson
 *               2011 David Goldwich
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * This is a demuxer for Sony OpenMG Music files
 *
 * Known file extensions: ".oma", "aa3"
 * The format of such files consists of three parts:
 * - "ea3" header carrying overall info and metadata. Except for starting with
 *   "ea" instead of "ID", it's an ID3v2 header.
 * - "EA3" header is a Sony-specific header containing information about
 *   the OpenMG file: codec type (usually ATRAC, can also be MP3 or WMA),
 *   codec specific info (packet size, sample rate, channels and so on)
 *   and DRM related info (file encryption, content id).
 * - Sound data organized in packets follow the EA3 header
 *   (can be encrypted using the Sony DRM!).
 *
 * CODEC SUPPORT: Only ATRAC3 codec is currently supported!
 */

#include "avformat.h"
#include "internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/des.h"
#include "pcm.h"
#include "riff.h"
#include "id3v2.h"

#define EA3_HEADER_SIZE 96
#define ID3v2_EA3_MAGIC "ea3"
#define OMA_ENC_HEADER_SIZE 16

enum {
    OMA_CODECID_ATRAC3  = 0,
    OMA_CODECID_ATRAC3P = 1,
    OMA_CODECID_MP3     = 3,
    OMA_CODECID_LPCM    = 4,
    OMA_CODECID_WMA     = 5,
};

static const AVCodecTag codec_oma_tags[] = {
    { CODEC_ID_ATRAC3,  OMA_CODECID_ATRAC3 },
    { CODEC_ID_ATRAC3P, OMA_CODECID_ATRAC3P },
    { CODEC_ID_MP3,     OMA_CODECID_MP3 },
};

static const uint64_t leaf_table[] = {
    0xd79e8283acea4620, 0x7a9762f445afd0d8,
    0x354d60a60b8c79f1, 0x584e1cde00b07aee,
    0x1573cd93da7df623, 0x47f98d79620dd535
};

typedef struct OMAContext {
    uint64_t content_start;
    int encrypted;
    uint16_t k_size;
    uint16_t e_size;
    uint16_t i_size;
    uint16_t s_size;
    uint32_t rid;
    uint8_t r_val[24];
    uint8_t n_val[24];
    uint8_t m_val[8];
    uint8_t s_val[8];
    uint8_t sm_val[8];
    uint8_t e_val[8];
    uint8_t iv[8];
    struct AVDES av_des;
} OMAContext;

static void hex_log(AVFormatContext *s, int level, const char *name, const uint8_t *value, int len)
{
    char buf[33];
    len = FFMIN(len, 16);
    if (av_log_get_level() < level)
        return;
    ff_data_to_hex(buf, value, len, 1);
    buf[len<<1] = '\0';
    av_log(s, level, "%s: %s\n", name, buf);
}

static int kset(AVFormatContext *s, const uint8_t *r_val, const uint8_t *n_val, int len)
{
    OMAContext *oc = s->priv_data;

    if (!r_val && !n_val)
        return -1;

    len = FFMIN(len, 16);

    /* use first 64 bits in the third round again */
    if (r_val) {
        if (r_val != oc->r_val) {
            memset(oc->r_val, 0, 24);
            memcpy(oc->r_val, r_val, len);
        }
        memcpy(&oc->r_val[16], r_val, 8);
    }
    if (n_val) {
        if (n_val != oc->n_val) {
            memset(oc->n_val, 0, 24);
            memcpy(oc->n_val, n_val, len);
        }
        memcpy(&oc->n_val[16], n_val, 8);
    }

    return 0;
}

static int rprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *r_val)
{
    OMAContext *oc = s->priv_data;
    unsigned int pos;
    struct AVDES av_des;

    if (!enc_header || !r_val)
        return -1;

    /* m_val */
    av_des_init(&av_des, r_val, 192, 1);
    av_des_crypt(&av_des, oc->m_val, &enc_header[48], 1, NULL, 1);

    /* s_val */
    av_des_init(&av_des, oc->m_val, 64, 0);
    av_des_crypt(&av_des, oc->s_val, NULL, 1, NULL, 0);

    /* sm_val */
    pos = OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size;
    av_des_init(&av_des, oc->s_val, 64, 0);
    av_des_mac(&av_des, oc->sm_val, &enc_header[pos], (oc->i_size >> 3));

    pos += oc->i_size;

    return memcmp(&enc_header[pos], oc->sm_val, 8) ? -1 : 0;
}

static int nprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *n_val)
{
    OMAContext *oc = s->priv_data;
    uint32_t pos, taglen, datalen;
    struct AVDES av_des;

    if (!enc_header || !n_val)
        return -1;

    pos = OMA_ENC_HEADER_SIZE + oc->k_size;
    if (!memcmp(&enc_header[pos], "EKB ", 4))
        pos += 32;

    if (AV_RB32(&enc_header[pos]) != oc->rid)
        av_log(s, AV_LOG_DEBUG, "Mismatching RID\n");

    taglen = AV_RB32(&enc_header[pos+32]);
    datalen = AV_RB32(&enc_header[pos+36]) >> 4;

    pos += 44 + taglen;

    av_des_init(&av_des, n_val, 192, 1);
    while (datalen-- > 0) {
        av_des_crypt(&av_des, oc->r_val, &enc_header[pos], 2, NULL, 1);
        kset(s, oc->r_val, NULL, 16);
        if (!rprobe(s, enc_header, oc->r_val))
            return 0;
        pos += 16;
    }

    return -1;
}

static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header)
{
    OMAContext *oc = s->priv_data;
    ID3v2ExtraMetaGEOB *geob = NULL;
    uint8_t *gdata;

    oc->encrypted = 1;
    av_log(s, AV_LOG_INFO, "File is encrypted\n");

    /* find GEOB metadata */
    while (em) {
        if (!strcmp(em->tag, "GEOB") &&
            (geob = em->data) &&
            !strcmp(geob->description, "OMG_LSI") ||
            !strcmp(geob->description, "OMG_BKLSI")) {
            break;
        }
        em = em->next;
    }
    if (!em) {
        av_log(s, AV_LOG_ERROR, "No encryption header found\n");
        return -1;
    }

    if (geob->datasize < 64) {
        av_log(s, AV_LOG_ERROR, "Invalid GEOB data size: %u\n", geob->datasize);
        return -1;
    }

    gdata = geob->data;

    if (AV_RB16(gdata) != 1)
        av_log(s, AV_LOG_WARNING, "Unknown version in encryption header\n");

    oc->k_size = AV_RB16(&gdata[2]);
    oc->e_size = AV_RB16(&gdata[4]);
    oc->i_size = AV_RB16(&gdata[6]);
    oc->s_size = AV_RB16(&gdata[8]);

    if (memcmp(&gdata[OMA_ENC_HEADER_SIZE], "KEYRING     ", 12)) {
        av_log(s, AV_LOG_ERROR, "Invalid encryption header\n");
        return -1;
    }
    oc->rid = AV_RB32(&gdata[OMA_ENC_HEADER_SIZE + 28]);
    av_log(s, AV_LOG_DEBUG, "RID: %.8x\n", oc->rid);

    memcpy(oc->iv, &header[0x58], 8);
    hex_log(s, AV_LOG_DEBUG, "IV", oc->iv, 8);

    hex_log(s, AV_LOG_DEBUG, "CBC-MAC", &gdata[OMA_ENC_HEADER_SIZE+oc->k_size+oc->e_size+oc->i_size], 8);

    if (s->keylen > 0) {
        kset(s, s->key, s->key, s->keylen);
    }
    if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) ||
        rprobe(s, gdata, oc->r_val) < 0 &&
        nprobe(s, gdata, oc->n_val) < 0) {
        int i;
        for (i = 0; i < sizeof(leaf_table); i += 2) {
            uint8_t buf[16];
            AV_WL64(buf, leaf_table[i]);
            AV_WL64(&buf[8], leaf_table[i+1]);
            kset(s, buf, buf, 16);
            if (!rprobe(s, gdata, oc->r_val) || !nprobe(s, gdata, oc->n_val))
                break;
        }
        if (i >= sizeof(leaf_table)) {
            av_log(s, AV_LOG_ERROR, "Invalid key\n");
            return -1;
        }
    }

    /* e_val */
    av_des_init(&oc->av_des, oc->m_val, 64, 0);
    av_des_crypt(&oc->av_des, oc->e_val, &gdata[OMA_ENC_HEADER_SIZE + 40], 1, NULL, 0);
    hex_log(s, AV_LOG_DEBUG, "EK", oc->e_val, 8);

    /* init e_val */
    av_des_init(&oc->av_des, oc->e_val, 64, 1);

    return 0;
}

static int oma_read_header(AVFormatContext *s,
                           AVFormatParameters *ap)
{
    static const uint16_t srate_tab[6] = {320,441,480,882,960,0};
    int     ret, framesize, jsflag, samplerate;
    uint32_t codec_params;
    int16_t eid;
    uint8_t buf[EA3_HEADER_SIZE];
    uint8_t *edata;
    AVStream *st;
    ID3v2ExtraMeta *extra_meta = NULL;
    OMAContext *oc = s->priv_data;

    ff_id3v2_read_all(s, ID3v2_EA3_MAGIC, &extra_meta);
    ret = avio_read(s->pb, buf, EA3_HEADER_SIZE);
    if (ret < EA3_HEADER_SIZE)
        return -1;

    if (memcmp(buf, ((const uint8_t[]){'E', 'A', '3'}),3) || buf[4] != 0 || buf[5] != EA3_HEADER_SIZE) {
        av_log(s, AV_LOG_ERROR, "Couldn't find the EA3 header !\n");
        return -1;
    }

    oc->content_start = avio_tell(s->pb);

    /* encrypted file */
    eid = AV_RB16(&buf[6]);
    if (eid != -1 && eid != -128 && decrypt_init(s, extra_meta, buf) < 0) {
        ff_id3v2_free_extra_meta(&extra_meta);
        return -1;
    }

    ff_id3v2_free_extra_meta(&extra_meta);

    codec_params = AV_RB24(&buf[33]);

    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);

    st->start_time = 0;
    st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
    st->codec->codec_tag   = buf[32];
    st->codec->codec_id    = ff_codec_get_id(codec_oma_tags, st->codec->codec_tag);

    switch (buf[32]) {
        case OMA_CODECID_ATRAC3:
            samplerate = srate_tab[(codec_params >> 13) & 7]*100;
            if (samplerate != 44100)
                av_log_ask_for_sample(s, "Unsupported sample rate: %d\n",
                                      samplerate);

            framesize = (codec_params & 0x3FF) * 8;
            jsflag = (codec_params >> 17) & 1; /* get stereo coding mode, 1 for joint-stereo */
            st->codec->channels    = 2;
            st->codec->sample_rate = samplerate;
            st->codec->bit_rate    = st->codec->sample_rate * framesize * 8 / 1024;

            /* fake the atrac3 extradata (wav format, makes stream copy to wav work) */
            st->codec->extradata_size = 14;
            edata = av_mallocz(14 + FF_INPUT_BUFFER_PADDING_SIZE);
            if (!edata)
                return AVERROR(ENOMEM);

            st->codec->extradata = edata;
            AV_WL16(&edata[0],  1);             // always 1
            AV_WL32(&edata[2],  samplerate);    // samples rate
            AV_WL16(&edata[6],  jsflag);        // coding mode
            AV_WL16(&edata[8],  jsflag);        // coding mode
            AV_WL16(&edata[10], 1);             // always 1
            // AV_WL16(&edata[12], 0);          // always 0

            avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
            break;
        case OMA_CODECID_ATRAC3P:
            st->codec->channels = (codec_params >> 10) & 7;
            framesize = ((codec_params & 0x3FF) * 8) + 8;
            st->codec->sample_rate = srate_tab[(codec_params >> 13) & 7]*100;
            st->codec->bit_rate    = st->codec->sample_rate * framesize * 8 / 1024;
            avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
            av_log(s, AV_LOG_ERROR, "Unsupported codec ATRAC3+!\n");
            break;
        case OMA_CODECID_MP3:
            st->need_parsing = AVSTREAM_PARSE_FULL;
            framesize = 1024;
            break;
        default:
            av_log(s, AV_LOG_ERROR, "Unsupported codec %d!\n",buf[32]);
            return -1;
    }

    st->codec->block_align = framesize;

    return 0;
}


static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    OMAContext *oc = s->priv_data;
    int packet_size = s->streams[0]->codec->block_align;
    int ret = av_get_packet(s->pb, pkt, packet_size);

    if (ret <= 0)
        return AVERROR(EIO);

    pkt->stream_index = 0;

    if (oc->encrypted) {
        /* previous unencrypted block saved in IV for the next packet (CBC mode) */
        av_des_crypt(&oc->av_des, pkt->data, pkt->data, (packet_size >> 3), oc->iv, 1);
    }

    return ret;
}

static int oma_read_probe(AVProbeData *p)
{
    const uint8_t *buf;
    unsigned tag_len = 0;

    buf = p->buf;
    /* version must be 3 and flags byte zero */
    if (ff_id3v2_match(buf, ID3v2_EA3_MAGIC) && buf[3] == 3 && !buf[4])
        tag_len = ff_id3v2_tag_len(buf);

    // This check cannot overflow as tag_len has at most 28 bits
    if (p->buf_size < tag_len + 5)
        return 0;

    buf += tag_len;

    if (!memcmp(buf, "EA3", 3) && !buf[4] && buf[5] == EA3_HEADER_SIZE)
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

static int oma_read_seek(struct AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
    OMAContext *oc = s->priv_data;

    pcm_read_seek(s, stream_index, timestamp, flags);

    if (oc->encrypted) {
        /* readjust IV for CBC */
        int64_t pos = avio_tell(s->pb);
        if (pos < oc->content_start)
            memset(oc->iv, 0, 8);
        else {
            if (avio_seek(s->pb, -8, SEEK_CUR) < 0 || avio_read(s->pb, oc->iv, 8) < 8) {
                memset(oc->iv, 0, 8);
                return -1;
            }
        }
    }

    return 0;
}

AVInputFormat ff_oma_demuxer = {
    .name           = "oma",
    .long_name      = NULL_IF_CONFIG_SMALL("Sony OpenMG audio"),
    .priv_data_size = sizeof(OMAContext),
    .read_probe     = oma_read_probe,
    .read_header    = oma_read_header,
    .read_packet    = oma_read_packet,
    .read_seek      = oma_read_seek,
    .flags          = AVFMT_GENERIC_INDEX,
    .extensions     = "oma,omg,aa3",
    .codec_tag      = (const AVCodecTag* const []){codec_oma_tags, 0},
};