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oma: support for encrypted files
Signed-off-by: David Goldwich <david.goldwich@gmail.com> Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
David Goldwich
Anton Khirnov
parent
7a019dffe5
commit
61f4387d39
@ -3,6 +3,7 @@
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*
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* Copyright (c) 2008 Maxim Poliakovski
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* 2008 Benjamin Larsson
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* 2011 David Goldwich
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*
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* This file is part of Libav.
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*
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@ -36,20 +37,19 @@
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* - Sound data organized in packets follow the EA3 header
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* (can be encrypted using the Sony DRM!).
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*
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* LIMITATIONS: This version supports only plain (unencrypted) OMA files.
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* If any DRM-protected (encrypted) file is encountered you will get the
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* corresponding error message. Try to remove the encryption using any
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* Sony software (for example SonicStage).
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* CODEC SUPPORT: Only ATRAC3 codec is currently supported!
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*/
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#include "avformat.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/des.h"
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#include "pcm.h"
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#include "riff.h"
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#include "id3v2.h"
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#define EA3_HEADER_SIZE 96
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#define ID3v2_EA3_MAGIC "ea3"
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#define OMA_ENC_HEADER_SIZE 16
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enum {
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OMA_CODECID_ATRAC3 = 0,
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@ -65,7 +65,211 @@ static const AVCodecTag codec_oma_tags[] = {
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{ CODEC_ID_MP3, OMA_CODECID_MP3 },
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};
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#define ID3v2_EA3_MAGIC "ea3"
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static const uint64_t leaf_table[] = {
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0xd79e8283acea4620, 0x7a9762f445afd0d8,
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0x354d60a60b8c79f1, 0x584e1cde00b07aee,
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0x1573cd93da7df623, 0x47f98d79620dd535
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};
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typedef struct OMAContext {
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uint64_t content_start;
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int encrypted;
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uint16_t k_size;
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uint16_t e_size;
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uint16_t i_size;
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uint16_t s_size;
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uint32_t rid;
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uint8_t r_val[24];
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uint8_t n_val[24];
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uint8_t m_val[8];
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uint8_t s_val[8];
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uint8_t sm_val[8];
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uint8_t e_val[8];
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uint8_t iv[8];
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struct AVDES av_des;
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} OMAContext;
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static void hex_log(AVFormatContext *s, int level, const char *name, const uint8_t *value, int len)
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{
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char buf[33];
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len = FFMIN(len, 16);
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if (av_log_get_level() < level)
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return;
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ff_data_to_hex(buf, value, len, 1);
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buf[len<<1] = '\0';
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av_log(s, level, "%s: %s\n", name, buf);
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}
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static int kset(AVFormatContext *s, const uint8_t *r_val, const uint8_t *n_val, int len)
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{
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OMAContext *oc = s->priv_data;
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if (!r_val && !n_val)
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return -1;
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len = FFMIN(len, 16);
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/* use first 64 bits in the third round again */
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if (r_val) {
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if (r_val != oc->r_val) {
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memset(oc->r_val, 0, 24);
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memcpy(oc->r_val, r_val, len);
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}
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memcpy(&oc->r_val[16], r_val, 8);
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}
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if (n_val) {
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if (n_val != oc->n_val) {
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memset(oc->n_val, 0, 24);
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memcpy(oc->n_val, n_val, len);
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}
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memcpy(&oc->n_val[16], n_val, 8);
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}
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return 0;
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}
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static int rprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *r_val)
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{
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OMAContext *oc = s->priv_data;
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unsigned int pos;
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struct AVDES av_des;
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if (!enc_header || !r_val)
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return -1;
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/* m_val */
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av_des_init(&av_des, r_val, 192, 1);
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av_des_crypt(&av_des, oc->m_val, &enc_header[48], 1, NULL, 1);
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/* s_val */
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av_des_init(&av_des, oc->m_val, 64, 0);
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av_des_crypt(&av_des, oc->s_val, NULL, 1, NULL, 0);
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/* sm_val */
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pos = OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size;
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av_des_init(&av_des, oc->s_val, 64, 0);
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av_des_mac(&av_des, oc->sm_val, &enc_header[pos], (oc->i_size >> 3));
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pos += oc->i_size;
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return memcmp(&enc_header[pos], oc->sm_val, 8) ? -1 : 0;
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}
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static int nprobe(AVFormatContext *s, uint8_t *enc_header, const uint8_t *n_val)
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{
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OMAContext *oc = s->priv_data;
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uint32_t pos, taglen, datalen;
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struct AVDES av_des;
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if (!enc_header || !n_val)
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return -1;
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pos = OMA_ENC_HEADER_SIZE + oc->k_size;
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if (!memcmp(&enc_header[pos], "EKB ", 4))
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pos += 32;
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if (AV_RB32(&enc_header[pos]) != oc->rid)
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av_log(s, AV_LOG_DEBUG, "Mismatching RID\n");
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taglen = AV_RB32(&enc_header[pos+32]);
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datalen = AV_RB32(&enc_header[pos+36]) >> 4;
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pos += 44 + taglen;
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av_des_init(&av_des, n_val, 192, 1);
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while (datalen-- > 0) {
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av_des_crypt(&av_des, oc->r_val, &enc_header[pos], 2, NULL, 1);
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kset(s, oc->r_val, NULL, 16);
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if (!rprobe(s, enc_header, oc->r_val))
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return 0;
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pos += 16;
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}
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return -1;
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}
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static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header)
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{
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OMAContext *oc = s->priv_data;
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ID3v2ExtraMetaGEOB *geob = NULL;
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uint8_t *gdata;
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oc->encrypted = 1;
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av_log(s, AV_LOG_INFO, "File is encrypted\n");
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/* find GEOB metadata */
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while (em) {
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if (!strcmp(em->tag, "GEOB") &&
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(geob = em->data) &&
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!strcmp(geob->description, "OMG_LSI") ||
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!strcmp(geob->description, "OMG_BKLSI")) {
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break;
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}
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em = em->next;
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}
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if (!em) {
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av_log(s, AV_LOG_ERROR, "No encryption header found\n");
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return -1;
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}
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if (geob->datasize < 64) {
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av_log(s, AV_LOG_ERROR, "Invalid GEOB data size: %u\n", geob->datasize);
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return -1;
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}
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gdata = geob->data;
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if (AV_RB16(gdata) != 1)
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av_log(s, AV_LOG_WARNING, "Unknown version in encryption header\n");
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oc->k_size = AV_RB16(&gdata[2]);
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oc->e_size = AV_RB16(&gdata[4]);
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oc->i_size = AV_RB16(&gdata[6]);
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oc->s_size = AV_RB16(&gdata[8]);
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if (memcmp(&gdata[OMA_ENC_HEADER_SIZE], "KEYRING ", 12)) {
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av_log(s, AV_LOG_ERROR, "Invalid encryption header\n");
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return -1;
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}
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oc->rid = AV_RB32(&gdata[OMA_ENC_HEADER_SIZE + 28]);
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av_log(s, AV_LOG_DEBUG, "RID: %.8x\n", oc->rid);
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memcpy(oc->iv, &header[0x58], 8);
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hex_log(s, AV_LOG_DEBUG, "IV", oc->iv, 8);
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hex_log(s, AV_LOG_DEBUG, "CBC-MAC", &gdata[OMA_ENC_HEADER_SIZE+oc->k_size+oc->e_size+oc->i_size], 8);
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if (s->keylen > 0) {
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kset(s, s->key, s->key, s->keylen);
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}
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if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) ||
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rprobe(s, gdata, oc->r_val) < 0 &&
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nprobe(s, gdata, oc->n_val) < 0) {
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int i;
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for (i = 0; i < sizeof(leaf_table); i += 2) {
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uint8_t buf[16];
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AV_WL64(buf, leaf_table[i]);
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AV_WL64(&buf[8], leaf_table[i+1]);
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kset(s, buf, buf, 16);
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if (!rprobe(s, gdata, oc->r_val) || !nprobe(s, gdata, oc->n_val))
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break;
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}
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if (i >= sizeof(leaf_table)) {
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av_log(s, AV_LOG_ERROR, "Invalid key\n");
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return -1;
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}
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}
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/* e_val */
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av_des_init(&oc->av_des, oc->m_val, 64, 0);
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av_des_crypt(&oc->av_des, oc->e_val, &gdata[OMA_ENC_HEADER_SIZE + 40], 1, NULL, 0);
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hex_log(s, AV_LOG_DEBUG, "EK", oc->e_val, 8);
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/* init e_val */
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av_des_init(&oc->av_des, oc->e_val, 64, 1);
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return 0;
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}
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static int oma_read_header(AVFormatContext *s,
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AVFormatParameters *ap)
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@ -77,8 +281,10 @@ static int oma_read_header(AVFormatContext *s,
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uint8_t buf[EA3_HEADER_SIZE];
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uint8_t *edata;
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AVStream *st;
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ID3v2ExtraMeta *extra_meta = NULL;
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OMAContext *oc = s->priv_data;
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ff_id3v2_read(s, ID3v2_EA3_MAGIC);
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ff_id3v2_read_all(s, ID3v2_EA3_MAGIC, &extra_meta);
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ret = avio_read(s->pb, buf, EA3_HEADER_SIZE);
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if (ret < EA3_HEADER_SIZE)
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return -1;
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@ -88,12 +294,17 @@ static int oma_read_header(AVFormatContext *s,
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return -1;
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}
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oc->content_start = avio_tell(s->pb);
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/* encrypted file */
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eid = AV_RB16(&buf[6]);
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if (eid != -1 && eid != -128) {
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av_log(s, AV_LOG_ERROR, "Encrypted file! Eid: %d\n", eid);
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if (eid != -1 && eid != -128 && decrypt_init(s, extra_meta, buf) < 0) {
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ff_id3v2_free_extra_meta(&extra_meta);
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return -1;
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}
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ff_id3v2_free_extra_meta(&extra_meta);
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codec_params = AV_RB24(&buf[33]);
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st = av_new_stream(s, 0);
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@ -159,12 +370,20 @@ static int oma_read_header(AVFormatContext *s,
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static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);
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OMAContext *oc = s->priv_data;
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int packet_size = s->streams[0]->codec->block_align;
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int ret = av_get_packet(s->pb, pkt, packet_size);
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pkt->stream_index = 0;
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if (ret <= 0)
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return AVERROR(EIO);
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pkt->stream_index = 0;
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if (oc->encrypted) {
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/* previous unencrypted block saved in IV for the next packet (CBC mode) */
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av_des_crypt(&oc->av_des, pkt->data, pkt->data, (packet_size >> 3), oc->iv, 1);
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}
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return ret;
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}
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@ -190,16 +409,38 @@ static int oma_read_probe(AVProbeData *p)
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return 0;
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}
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static int oma_read_seek(struct AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
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{
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OMAContext *oc = s->priv_data;
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pcm_read_seek(s, stream_index, timestamp, flags);
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if (oc->encrypted) {
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/* readjust IV for CBC */
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int64_t pos = avio_tell(s->pb);
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if (pos < oc->content_start)
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memset(oc->iv, 0, 8);
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else {
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if (avio_seek(s->pb, -8, SEEK_CUR) < 0 || avio_read(s->pb, oc->iv, 8) < 8) {
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memset(oc->iv, 0, 8);
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return -1;
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}
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}
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}
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return 0;
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}
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AVInputFormat ff_oma_demuxer = {
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.name = "oma",
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.long_name = NULL_IF_CONFIG_SMALL("Sony OpenMG audio"),
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.priv_data_size = sizeof(OMAContext),
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.read_probe = oma_read_probe,
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.read_header = oma_read_header,
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.read_packet = oma_read_packet,
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.read_seek = pcm_read_seek,
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.flags= AVFMT_GENERIC_INDEX,
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.extensions = "oma,aa3",
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.codec_tag= (const AVCodecTag* const []){codec_oma_tags, 0},
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.read_seek = oma_read_seek,
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.flags = AVFMT_GENERIC_INDEX,
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.extensions = "oma,omg,aa3",
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.codec_tag = (const AVCodecTag* const []){codec_oma_tags, 0},
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};
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