On 09/02/2011 12:52 PM, Diego Elio Pettenò wrote:
> Il giorno ven, 02/09/2011 alle 08.21 +0200, David Goldwich ha scritto:
>>
>> +const uint64_t leaf_table[] = {
>
> I don't see this exposed by a header; shouldn't this be static const?
>
Yes, it should be. Fixed.
>From d77196bb12fd071cd28e689466582b88bc6f78d8 Mon Sep 17 00:00:00 2001
From: David Goldwich <[email protected]>
Date: Thu, 1 Sep 2011 21:41:13 +0200
Subject: [PATCH 3/3] oma: support for encrypted files
Signed-off-by: David Goldwich <[email protected]>
---
Changelog | 1 +
libavformat/oma.c | 260 ++++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 247 insertions(+), 14 deletions(-)
diff --git a/Changelog b/Changelog
index 510de33..ff68a43 100644
--- a/Changelog
+++ b/Changelog
@@ -42,6 +42,7 @@ easier to use. The changes are:
* -intra option was removed, it's equivalent to -g 0.
- XMV demuxer
- Windows Media Image decoder
+- Encrypted OMA files support
version 0.7:
diff --git a/libavformat/oma.c b/libavformat/oma.c
index 7675841..a4089e2 100644
--- a/libavformat/oma.c
+++ b/libavformat/oma.c
@@ -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 +65,126 @@ 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, 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");
+
+ datalen = AV_RB32(&enc_header[pos+36]) >> 4;
+ pos += 56;
+
+ 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 oma_read_header(AVFormatContext *s,
AVFormatParameters *ap)
@@ -77,8 +196,12 @@ static int oma_read_header(AVFormatContext *s,
uint8_t buf[EA3_HEADER_SIZE];
uint8_t *edata;
AVStream *st;
+ ID3v2ExtraMeta *extra_meta = NULL;
+ ID3v2ExtraMetaGEOB *geob = NULL;
+ uint8_t *gdata;
+ 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;
@@ -88,10 +211,87 @@ static int oma_read_header(AVFormatContext *s,
return -1;
}
+ oc->content_start = avio_tell(s->pb);
+
eid = AV_RB16(&buf[6]);
if (eid != -1 && eid != -128) {
- av_log(s, AV_LOG_ERROR, "Encrypted file! Eid: %d\n", eid);
- return -1;
+ /* encrypted file */
+
+ ID3v2ExtraMeta *em = extra_meta;
+
+ 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, &buf[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);
}
codec_params = AV_RB24(&buf[33]);
@@ -153,18 +353,28 @@ static int oma_read_header(AVFormatContext *s,
st->codec->block_align = framesize;
+ ff_id3v2_free_extra_meta(&extra_meta);
+
return 0;
}
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 +400,38 @@ 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,aa3",
+ .codec_tag = (const AVCodecTag* const []){codec_oma_tags, 0},
};
--
1.7.2.5
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