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omadec.c
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1 /*
2  * Sony OpenMG (OMA) demuxer
3  *
4  * Copyright (c) 2008 Maxim Poliakovski
5  * 2008 Benjamin Larsson
6  * 2011 David Goldwich
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 /**
26  * @file
27  * This is a demuxer for Sony OpenMG Music files
28  *
29  * Known file extensions: ".oma", "aa3"
30  * The format of such files consists of three parts:
31  * - "ea3" header carrying overall info and metadata. Except for starting with
32  * "ea" instead of "ID", it's an ID3v2 header.
33  * - "EA3" header is a Sony-specific header containing information about
34  * the OpenMG file: codec type (usually ATRAC, can also be MP3 or WMA),
35  * codec specific info (packet size, sample rate, channels and so on)
36  * and DRM related info (file encryption, content id).
37  * - Sound data organized in packets follow the EA3 header
38  * (can be encrypted using the Sony DRM!).
39  *
40  */
41 
43 #include "avformat.h"
44 #include "internal.h"
45 #include "libavutil/intreadwrite.h"
46 #include "libavutil/des.h"
47 #include "oma.h"
48 #include "pcm.h"
49 #include "id3v2.h"
50 
51 
52 static const uint64_t leaf_table[] = {
53  0xd79e8283acea4620, 0x7a9762f445afd0d8,
54  0x354d60a60b8c79f1, 0x584e1cde00b07aee,
55  0x1573cd93da7df623, 0x47f98d79620dd535
56 };
57 
58 typedef struct OMAContext {
59  uint64_t content_start;
60  int encrypted;
61  uint16_t k_size;
62  uint16_t e_size;
63  uint16_t i_size;
64  uint16_t s_size;
65  uint32_t rid;
72  uint8_t iv[8];
73  struct AVDES av_des;
74 } OMAContext;
75 
76 static void hex_log(AVFormatContext *s, int level, const char *name, const uint8_t *value, int len)
77 {
78  char buf[33];
79  len = FFMIN(len, 16);
80  if (av_log_get_level() < level)
81  return;
82  ff_data_to_hex(buf, value, len, 1);
83  buf[len<<1] = '\0';
84  av_log(s, level, "%s: %s\n", name, buf);
85 }
86 
87 static int kset(AVFormatContext *s, const uint8_t *r_val, const uint8_t *n_val, int len)
88 {
89  OMAContext *oc = s->priv_data;
90 
91  if (!r_val && !n_val)
92  return -1;
93 
94  len = FFMIN(len, 16);
95 
96  /* use first 64 bits in the third round again */
97  if (r_val) {
98  if (r_val != oc->r_val) {
99  memset(oc->r_val, 0, 24);
100  memcpy(oc->r_val, r_val, len);
101  }
102  memcpy(&oc->r_val[16], r_val, 8);
103  }
104  if (n_val) {
105  if (n_val != oc->n_val) {
106  memset(oc->n_val, 0, 24);
107  memcpy(oc->n_val, n_val, len);
108  }
109  memcpy(&oc->n_val[16], n_val, 8);
110  }
111 
112  return 0;
113 }
114 
115 static int rprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *r_val)
116 {
117  OMAContext *oc = s->priv_data;
118  unsigned int pos;
119  struct AVDES av_des;
120 
121  if (!enc_header || !r_val)
122  return -1;
123 
124  /* m_val */
125  av_des_init(&av_des, r_val, 192, 1);
126  av_des_crypt(&av_des, oc->m_val, &enc_header[48], 1, NULL, 1);
127 
128  /* s_val */
129  av_des_init(&av_des, oc->m_val, 64, 0);
130  av_des_crypt(&av_des, oc->s_val, NULL, 1, NULL, 0);
131 
132  /* sm_val */
133  pos = OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size;
134  av_des_init(&av_des, oc->s_val, 64, 0);
135  av_des_mac(&av_des, oc->sm_val, &enc_header[pos], (oc->i_size >> 3));
136 
137  pos += oc->i_size;
138 
139  return memcmp(&enc_header[pos], oc->sm_val, 8) ? -1 : 0;
140 }
141 
142 static int nprobe(AVFormatContext *s, uint8_t *enc_header, int size, const uint8_t *n_val)
143 {
144  OMAContext *oc = s->priv_data;
145  uint32_t pos, taglen, datalen;
146  struct AVDES av_des;
147 
148  if (!enc_header || !n_val)
149  return -1;
150 
151  pos = OMA_ENC_HEADER_SIZE + oc->k_size;
152  if (!memcmp(&enc_header[pos], "EKB ", 4))
153  pos += 32;
154 
155  if (AV_RB32(&enc_header[pos]) != oc->rid)
156  av_log(s, AV_LOG_DEBUG, "Mismatching RID\n");
157 
158  taglen = AV_RB32(&enc_header[pos+32]);
159  datalen = AV_RB32(&enc_header[pos+36]) >> 4;
160 
161  if(pos + (uint64_t)taglen + (((uint64_t)datalen)<<4) + 44 > size)
162  return -1;
163 
164  pos += 44 + taglen;
165 
166  av_des_init(&av_des, n_val, 192, 1);
167  while (datalen-- > 0) {
168  av_des_crypt(&av_des, oc->r_val, &enc_header[pos], 2, NULL, 1);
169  kset(s, oc->r_val, NULL, 16);
170  if (!rprobe(s, enc_header, oc->r_val))
171  return 0;
172  pos += 16;
173  }
174 
175  return -1;
176 }
177 
179 {
180  OMAContext *oc = s->priv_data;
181  ID3v2ExtraMetaGEOB *geob = NULL;
182  uint8_t *gdata;
183 
184  oc->encrypted = 1;
185  av_log(s, AV_LOG_INFO, "File is encrypted\n");
186 
187  /* find GEOB metadata */
188  while (em) {
189  if (!strcmp(em->tag, "GEOB") &&
190  (geob = em->data) &&
191  (!strcmp(geob->description, "OMG_LSI") ||
192  !strcmp(geob->description, "OMG_BKLSI"))) {
193  break;
194  }
195  em = em->next;
196  }
197  if (!em) {
198  av_log(s, AV_LOG_ERROR, "No encryption header found\n");
199  return -1;
200  }
201 
202  if (geob->datasize < 64) {
203  av_log(s, AV_LOG_ERROR, "Invalid GEOB data size: %u\n", geob->datasize);
204  return -1;
205  }
206 
207  gdata = geob->data;
208 
209  if (AV_RB16(gdata) != 1)
210  av_log(s, AV_LOG_WARNING, "Unknown version in encryption header\n");
211 
212  oc->k_size = AV_RB16(&gdata[2]);
213  oc->e_size = AV_RB16(&gdata[4]);
214  oc->i_size = AV_RB16(&gdata[6]);
215  oc->s_size = AV_RB16(&gdata[8]);
216 
217  if (memcmp(&gdata[OMA_ENC_HEADER_SIZE], "KEYRING ", 12)) {
218  av_log(s, AV_LOG_ERROR, "Invalid encryption header\n");
219  return -1;
220  }
221  if ( OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size + 8 > geob->datasize
222  || OMA_ENC_HEADER_SIZE + 48 > geob->datasize
223  ) {
224  av_log(s, AV_LOG_ERROR, "Too little GEOB data\n");
225  return AVERROR_INVALIDDATA;
226  }
227  oc->rid = AV_RB32(&gdata[OMA_ENC_HEADER_SIZE + 28]);
228  av_log(s, AV_LOG_DEBUG, "RID: %.8x\n", oc->rid);
229 
230  memcpy(oc->iv, &header[0x58], 8);
231  hex_log(s, AV_LOG_DEBUG, "IV", oc->iv, 8);
232 
233  hex_log(s, AV_LOG_DEBUG, "CBC-MAC", &gdata[OMA_ENC_HEADER_SIZE+oc->k_size+oc->e_size+oc->i_size], 8);
234 
235  if (s->keylen > 0) {
236  kset(s, s->key, s->key, s->keylen);
237  }
238  if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) ||
239  rprobe(s, gdata, oc->r_val) < 0 &&
240  nprobe(s, gdata, geob->datasize, oc->n_val) < 0) {
241  int i;
242  for (i = 0; i < FF_ARRAY_ELEMS(leaf_table); i += 2) {
243  uint8_t buf[16];
244  AV_WL64(buf, leaf_table[i]);
245  AV_WL64(&buf[8], leaf_table[i+1]);
246  kset(s, buf, buf, 16);
247  if (!rprobe(s, gdata, oc->r_val) || !nprobe(s, gdata, geob->datasize, oc->n_val))
248  break;
249  }
250  if (i >= FF_ARRAY_ELEMS(leaf_table)) {
251  av_log(s, AV_LOG_ERROR, "Invalid key\n");
252  return -1;
253  }
254  }
255 
256  /* e_val */
257  av_des_init(&oc->av_des, oc->m_val, 64, 0);
258  av_des_crypt(&oc->av_des, oc->e_val, &gdata[OMA_ENC_HEADER_SIZE + 40], 1, NULL, 0);
259  hex_log(s, AV_LOG_DEBUG, "EK", oc->e_val, 8);
260 
261  /* init e_val */
262  av_des_init(&oc->av_des, oc->e_val, 64, 1);
263 
264  return 0;
265 }
266 
268 {
269  int ret, framesize, jsflag, samplerate;
270  uint32_t codec_params;
271  int16_t eid;
273  uint8_t *edata;
274  AVStream *st;
275  ID3v2ExtraMeta *extra_meta = NULL;
276  OMAContext *oc = s->priv_data;
277 
278  ff_id3v2_read(s, ID3v2_EA3_MAGIC, &extra_meta);
279  ret = avio_read(s->pb, buf, EA3_HEADER_SIZE);
280  if (ret < EA3_HEADER_SIZE)
281  return -1;
282 
283  if (memcmp(buf, ((const uint8_t[]){'E', 'A', '3'}),3) || buf[4] != 0 || buf[5] != EA3_HEADER_SIZE) {
284  av_log(s, AV_LOG_ERROR, "Couldn't find the EA3 header !\n");
285  return -1;
286  }
287 
288  oc->content_start = avio_tell(s->pb);
289 
290  /* encrypted file */
291  eid = AV_RB16(&buf[6]);
292  if (eid != -1 && eid != -128 && decrypt_init(s, extra_meta, buf) < 0) {
293  ff_id3v2_free_extra_meta(&extra_meta);
294  return -1;
295  }
296 
297  ff_id3v2_free_extra_meta(&extra_meta);
298 
299  codec_params = AV_RB24(&buf[33]);
300 
301  st = avformat_new_stream(s, NULL);
302  if (!st)
303  return AVERROR(ENOMEM);
304 
305  st->start_time = 0;
307  st->codec->codec_tag = buf[32];
309 
310  switch (buf[32]) {
311  case OMA_CODECID_ATRAC3:
312  samplerate = ff_oma_srate_tab[(codec_params >> 13) & 7]*100;
313  if (samplerate != 44100)
314  av_log_ask_for_sample(s, "Unsupported sample rate: %d\n",
315  samplerate);
316 
317  framesize = (codec_params & 0x3FF) * 8;
318  jsflag = (codec_params >> 17) & 1; /* get stereo coding mode, 1 for joint-stereo */
319  st->codec->channels = 2;
321  st->codec->sample_rate = samplerate;
322  st->codec->bit_rate = st->codec->sample_rate * framesize * 8 / 1024;
323 
324  /* fake the atrac3 extradata (wav format, makes stream copy to wav work) */
325  st->codec->extradata_size = 14;
327  if (!edata)
328  return AVERROR(ENOMEM);
329 
330  st->codec->extradata = edata;
331  AV_WL16(&edata[0], 1); // always 1
332  AV_WL32(&edata[2], samplerate); // samples rate
333  AV_WL16(&edata[6], jsflag); // coding mode
334  AV_WL16(&edata[8], jsflag); // coding mode
335  AV_WL16(&edata[10], 1); // always 1
336  // AV_WL16(&edata[12], 0); // always 0
337 
338  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
339  break;
340  case OMA_CODECID_ATRAC3P:
341  st->codec->channels = (codec_params >> 10) & 7;
342  framesize = ((codec_params & 0x3FF) * 8) + 8;
343  st->codec->sample_rate = ff_oma_srate_tab[(codec_params >> 13) & 7]*100;
344  st->codec->bit_rate = st->codec->sample_rate * framesize * 8 / 1024;
345  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
346  av_log(s, AV_LOG_ERROR, "Unsupported codec ATRAC3+!\n");
347  break;
348  case OMA_CODECID_MP3:
350  framesize = 1024;
351  break;
352  case OMA_CODECID_LPCM:
353  /* PCM 44.1 kHz 16 bit stereo big-endian */
354  st->codec->channels = 2;
356  st->codec->sample_rate = 44100;
357  framesize = 1024;
358  /* bit rate = sample rate x PCM block align (= 4) x 8 */
359  st->codec->bit_rate = st->codec->sample_rate * 32;
361  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
362  break;
363  default:
364  av_log(s, AV_LOG_ERROR, "Unsupported codec %d!\n",buf[32]);
365  return -1;
366  }
367 
368  st->codec->block_align = framesize;
369 
370  return 0;
371 }
372 
373 
375 {
376  OMAContext *oc = s->priv_data;
377  int packet_size = s->streams[0]->codec->block_align;
378  int ret = av_get_packet(s->pb, pkt, packet_size);
379 
380  if (ret <= 0)
381  return AVERROR(EIO);
382 
383  pkt->stream_index = 0;
384 
385  if (oc->encrypted) {
386  /* previous unencrypted block saved in IV for the next packet (CBC mode) */
387  av_des_crypt(&oc->av_des, pkt->data, pkt->data, (ret >> 3), oc->iv, 1);
388  }
389 
390  return ret;
391 }
392 
394 {
395  const uint8_t *buf;
396  unsigned tag_len = 0;
397 
398  buf = p->buf;
399 
400  if (p->buf_size < ID3v2_HEADER_SIZE ||
402  buf[3] != 3 || // version must be 3
403  buf[4]) // flags byte zero
404  return 0;
405 
406  tag_len = ff_id3v2_tag_len(buf);
407 
408  /* This check cannot overflow as tag_len has at most 28 bits */
409  if (p->buf_size < tag_len + 5)
410  /* EA3 header comes late, might be outside of the probe buffer */
411  return AVPROBE_SCORE_MAX / 2;
412 
413  buf += tag_len;
414 
415  if (!memcmp(buf, "EA3", 3) && !buf[4] && buf[5] == EA3_HEADER_SIZE)
416  return AVPROBE_SCORE_MAX;
417  else
418  return 0;
419 }
420 
421 static int oma_read_seek(struct AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
422 {
423  OMAContext *oc = s->priv_data;
424 
425  ff_pcm_read_seek(s, stream_index, timestamp, flags);
426 
427  if (oc->encrypted) {
428  /* readjust IV for CBC */
429  int64_t pos = avio_tell(s->pb);
430  if (pos < oc->content_start)
431  memset(oc->iv, 0, 8);
432  else {
433  if (avio_seek(s->pb, -8, SEEK_CUR) < 0 || avio_read(s->pb, oc->iv, 8) < 8) {
434  memset(oc->iv, 0, 8);
435  return -1;
436  }
437  }
438  }
439 
440  return 0;
441 }
442 
444  .name = "oma",
445  .long_name = NULL_IF_CONFIG_SMALL("Sony OpenMG audio"),
446  .priv_data_size = sizeof(OMAContext),
452  .extensions = "oma,omg,aa3",
453  .codec_tag = (const AVCodecTag* const []){ff_oma_codec_tags, 0},
454 };