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oma: support for encrypted files

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Signed-off-by: David Goldwich <david.goldwich@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
pull/2/head
David Goldwich 14 years ago committed by Anton Khirnov
parent 7a019dffe5
commit 61f4387d39
1 changed files with 255 additions and 14 deletions
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  1. 269
      libavformat/oma.c

269
libavformat/oma.c
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@ -3,6 +3,7 @@
*
* Copyright (c) 2008 Maxim Poliakovski
* 2008 Benjamin Larsson
* 2011 David Goldwich
*
* This file is part of Libav.
*
@ -36,20 +37,19 @@
* - Sound data organized in packets follow the EA3 header
* (can be encrypted using the Sony DRM!).
*
* LIMITATIONS: This version supports only plain (unencrypted) OMA files.
* If any DRM-protected (encrypted) file is encountered you will get the
* corresponding error message. Try to remove the encryption using any
* Sony software (for example SonicStage).
* CODEC SUPPORT: Only ATRAC3 codec is currently supported!
*/
#include "avformat.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,
@ -65,7 +65,211 @@ static const AVCodecTag codec_oma_tags[] = {
{ CODEC_ID_MP3, OMA_CODECID_MP3 },
};
#define ID3v2_EA3_MAGIC "ea3"
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)
@ -77,8 +281,10 @@ static int oma_read_header(AVFormatContext *s,
uint8_t buf[EA3_HEADER_SIZE];
uint8_t *edata;
AVStream *st;
ID3v2ExtraMeta *extra_meta = NULL;
OMAContext *oc = s->priv_data;
ff_id3v2_read(s, ID3v2_EA3_MAGIC);
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;
@ -88,12 +294,17 @@ static int oma_read_header(AVFormatContext *s,
return -1;
}
oc->content_start = avio_tell(s->pb);
/* encrypted file */
eid = AV_RB16(&buf[6]);
if (eid != -1 && eid != -128) {
av_log(s, AV_LOG_ERROR, "Encrypted file! Eid: %d\n", eid);
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 = av_new_stream(s, 0);
@ -159,12 +370,20 @@ static int oma_read_header(AVFormatContext *s,
static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);
OMAContext *oc = s->priv_data;
int packet_size = s->streams[0]->codec->block_align;
int ret = av_get_packet(s->pb, pkt, packet_size);
pkt->stream_index = 0;
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;
}
@ -190,16 +409,38 @@ static int oma_read_probe(AVProbeData *p)
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 = pcm_read_seek,
.flags= AVFMT_GENERIC_INDEX,
.extensions = "oma,aa3",
.codec_tag= (const AVCodecTag* const []){codec_oma_tags, 0},
.read_seek = oma_read_seek,
.flags = AVFMT_GENERIC_INDEX,
.extensions = "oma,omg,aa3",
.codec_tag = (const AVCodecTag* const []){codec_oma_tags, 0},
};

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