libavformat/hls: add support for decryption of HLS media segments encrypted using SAMPLE-AES encryption method
Apple HTTP Live Streaming Sample Encryption: https://developer.apple.com/library/ios/documentation/AudioVideo/Conceptual/HLS_Sample_Encryption Signed-off-by: Nachiket Tarate <nachiket.programmer@gmail.com> Signed-off-by: Steven Liu <lq@chinaffmpeg.org>pull/370/head
Nachiket Tarate
4 years ago
committed by
Steven Liu
parent
ef0f5d1be6
commit
ff958b3846
5 changed files with 576 additions and 19 deletions
@ -0,0 +1,389 @@ |
||||
/*
|
||||
* Apple HTTP Live Streaming Sample Encryption/Decryption |
||||
* |
||||
* Copyright (c) 2021 Nachiket Tarate |
||||
* |
||||
* This file is part of FFmpeg. |
||||
* |
||||
* FFmpeg 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. |
||||
* |
||||
* FFmpeg 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 FFmpeg; if not, write to the Free Software |
||||
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
||||
*/ |
||||
|
||||
/**
|
||||
* @file |
||||
* Apple HTTP Live Streaming Sample Encryption |
||||
* https://developer.apple.com/library/ios/documentation/AudioVideo/Conceptual/HLS_Sample_Encryption
|
||||
*/ |
||||
|
||||
#include "hls_sample_encryption.h" |
||||
|
||||
#include "libavcodec/adts_header.h" |
||||
#include "libavcodec/adts_parser.h" |
||||
#include "libavcodec/ac3_parser_internal.h" |
||||
|
||||
|
||||
typedef struct NALUnit { |
||||
uint8_t *data; |
||||
int type; |
||||
int length; |
||||
int start_code_length; |
||||
} NALUnit; |
||||
|
||||
typedef struct AudioFrame { |
||||
uint8_t *data; |
||||
int length; |
||||
int header_length; |
||||
} AudioFrame; |
||||
|
||||
typedef struct CodecParserContext { |
||||
const uint8_t *buf_ptr; |
||||
const uint8_t *buf_end; |
||||
} CodecParserContext; |
||||
|
||||
static const int eac3_sample_rate_tab[] = { 48000, 44100, 32000, 0 }; |
||||
|
||||
void ff_hls_senc_read_audio_setup_info(HLSAudioSetupInfo *info, const uint8_t *buf, size_t size) |
||||
{ |
||||
if (size < 8) |
||||
return; |
||||
|
||||
info->codec_tag = AV_RL32(buf); |
||||
|
||||
if (info->codec_tag == MKTAG('z','a','a','c')) |
||||
info->codec_id = AV_CODEC_ID_AAC; |
||||
else if (info->codec_tag == MKTAG('z','a','c','3')) |
||||
info->codec_id = AV_CODEC_ID_AC3; |
||||
else if (info->codec_tag == MKTAG('z','e','c','3')) |
||||
info->codec_id = AV_CODEC_ID_EAC3; |
||||
else |
||||
info->codec_id = AV_CODEC_ID_NONE; |
||||
|
||||
buf += 4; |
||||
info->priming = AV_RL16(buf); |
||||
buf += 2; |
||||
info->version = *buf++; |
||||
info->setup_data_length = *buf++; |
||||
|
||||
if (info->setup_data_length > size - 8) |
||||
info->setup_data_length = size - 8; |
||||
|
||||
if (info->setup_data_length > HLS_MAX_AUDIO_SETUP_DATA_LEN) |
||||
return; |
||||
|
||||
memcpy(info->setup_data, buf, info->setup_data_length); |
||||
} |
||||
|
||||
int ff_hls_senc_parse_audio_setup_info(AVStream *st, HLSAudioSetupInfo *info) |
||||
{ |
||||
int ret = 0; |
||||
|
||||
st->codecpar->codec_tag = info->codec_tag; |
||||
|
||||
if (st->codecpar->codec_id == AV_CODEC_ID_AAC) |
||||
return 0; |
||||
|
||||
if (st->codecpar->codec_id != AV_CODEC_ID_AC3 && st->codecpar->codec_id != AV_CODEC_ID_EAC3) |
||||
return AVERROR_INVALIDDATA; |
||||
|
||||
if (st->codecpar->codec_id == AV_CODEC_ID_AC3) { |
||||
AC3HeaderInfo *ac3hdr = NULL; |
||||
|
||||
ret = avpriv_ac3_parse_header(&ac3hdr, info->setup_data, info->setup_data_length); |
||||
if (ret < 0) { |
||||
if (ret != AVERROR(ENOMEM)) |
||||
av_free(ac3hdr); |
||||
return ret; |
||||
} |
||||
|
||||
st->codecpar->sample_rate = ac3hdr->sample_rate; |
||||
st->codecpar->channels = ac3hdr->channels; |
||||
st->codecpar->channel_layout = ac3hdr->channel_layout; |
||||
st->codecpar->bit_rate = ac3hdr->bit_rate; |
||||
|
||||
av_free(ac3hdr); |
||||
} else { /* Parse 'dec3' EC3SpecificBox */ |
||||
GetBitContext gb; |
||||
int data_rate, fscod, acmod, lfeon; |
||||
|
||||
ret = init_get_bits8(&gb, info->setup_data, info->setup_data_length); |
||||
if (ret < 0) |
||||
return AVERROR_INVALIDDATA; |
||||
|
||||
data_rate = get_bits(&gb, 13); |
||||
skip_bits(&gb, 3); |
||||
fscod = get_bits(&gb, 2); |
||||
skip_bits(&gb, 10); |
||||
acmod = get_bits(&gb, 3); |
||||
lfeon = get_bits(&gb, 1); |
||||
|
||||
st->codecpar->sample_rate = eac3_sample_rate_tab[fscod]; |
||||
|
||||
st->codecpar->channel_layout = avpriv_ac3_channel_layout_tab[acmod]; |
||||
if (lfeon) |
||||
st->codecpar->channel_layout |= AV_CH_LOW_FREQUENCY; |
||||
|
||||
st->codecpar->channels = av_get_channel_layout_nb_channels(st->codecpar->channel_layout); |
||||
|
||||
st->codecpar->bit_rate = data_rate*1000; |
||||
} |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
/*
|
||||
* Remove start code emulation prevention 0x03 bytes |
||||
*/ |
||||
static void remove_scep_3_bytes(NALUnit *nalu) |
||||
{ |
||||
int i = 0; |
||||
int j = 0; |
||||
|
||||
uint8_t *data = nalu->data; |
||||
|
||||
while (i < nalu->length) { |
||||
if (nalu->length - i > 3 && AV_RB24(&data[i]) == 0x000003) { |
||||
data[j++] = data[i++]; |
||||
data[j++] = data[i++]; |
||||
i++; |
||||
} else { |
||||
data[j++] = data[i++]; |
||||
} |
||||
} |
||||
|
||||
nalu->length = j; |
||||
} |
||||
|
||||
static int get_next_nal_unit(CodecParserContext *ctx, NALUnit *nalu) |
||||
{ |
||||
const uint8_t *nalu_start = ctx->buf_ptr; |
||||
|
||||
if (ctx->buf_end - ctx->buf_ptr >= 4 && AV_RB32(ctx->buf_ptr) == 0x00000001) |
||||
nalu->start_code_length = 4; |
||||
else if (ctx->buf_end - ctx->buf_ptr >= 3 && AV_RB24(ctx->buf_ptr) == 0x000001) |
||||
nalu->start_code_length = 3; |
||||
else /* No start code at the beginning of the NAL unit */ |
||||
return -1; |
||||
|
||||
ctx->buf_ptr += nalu->start_code_length; |
||||
|
||||
while (ctx->buf_ptr < ctx->buf_end) { |
||||
if (ctx->buf_end - ctx->buf_ptr >= 4 && AV_RB32(ctx->buf_ptr) == 0x00000001) |
||||
break; |
||||
else if (ctx->buf_end - ctx->buf_ptr >= 3 && AV_RB24(ctx->buf_ptr) == 0x000001) |
||||
break; |
||||
ctx->buf_ptr++; |
||||
} |
||||
|
||||
nalu->data = (uint8_t *)nalu_start + nalu->start_code_length; |
||||
nalu->length = ctx->buf_ptr - nalu->data; |
||||
nalu->type = *nalu->data & 0x1F; |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int decrypt_nal_unit(HLSCryptoContext *crypto_ctx, NALUnit *nalu) |
||||
{ |
||||
int ret = 0; |
||||
int rem_bytes; |
||||
uint8_t *data; |
||||
uint8_t iv[16]; |
||||
|
||||
ret = av_aes_init(crypto_ctx->aes_ctx, crypto_ctx->key, 16 * 8, 1); |
||||
if (ret < 0) |
||||
return ret; |
||||
|
||||
/* Remove start code emulation prevention 0x03 bytes */ |
||||
remove_scep_3_bytes(nalu); |
||||
|
||||
data = nalu->data + 32; |
||||
rem_bytes = nalu->length - 32; |
||||
|
||||
memcpy(iv, crypto_ctx->iv, 16); |
||||
|
||||
while (rem_bytes > 0) { |
||||
if (rem_bytes > 16) { |
||||
av_aes_crypt(crypto_ctx->aes_ctx, data, data, 1, iv, 1); |
||||
data += 16; |
||||
rem_bytes -= 16; |
||||
} |
||||
data += FFMIN(144, rem_bytes); |
||||
rem_bytes -= FFMIN(144, rem_bytes); |
||||
} |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int decrypt_video_frame(HLSCryptoContext *crypto_ctx, AVPacket *pkt) |
||||
{ |
||||
int ret = 0; |
||||
CodecParserContext ctx; |
||||
NALUnit nalu; |
||||
uint8_t *data_ptr; |
||||
int move_nalu = 0; |
||||
|
||||
memset(&ctx, 0, sizeof(ctx)); |
||||
ctx.buf_ptr = pkt->data; |
||||
ctx.buf_end = pkt->data + pkt->size; |
||||
|
||||
data_ptr = pkt->data; |
||||
|
||||
while (ctx.buf_ptr < ctx.buf_end) { |
||||
memset(&nalu, 0, sizeof(nalu)); |
||||
ret = get_next_nal_unit(&ctx, &nalu); |
||||
if (ret < 0) |
||||
return ret; |
||||
if ((nalu.type == 0x01 || nalu.type == 0x05) && nalu.length > 48) { |
||||
int encrypted_nalu_length = nalu.length; |
||||
ret = decrypt_nal_unit(crypto_ctx, &nalu); |
||||
if (ret < 0) |
||||
return ret; |
||||
move_nalu = nalu.length != encrypted_nalu_length; |
||||
} |
||||
if (move_nalu) |
||||
memmove(data_ptr, nalu.data - nalu.start_code_length, nalu.start_code_length + nalu.length); |
||||
data_ptr += nalu.start_code_length + nalu.length; |
||||
} |
||||
|
||||
av_shrink_packet(pkt, data_ptr - pkt->data); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int get_next_adts_frame(CodecParserContext *ctx, AudioFrame *frame) |
||||
{ |
||||
int ret = 0; |
||||
|
||||
AACADTSHeaderInfo *adts_hdr = NULL; |
||||
|
||||
/* Find next sync word 0xFFF */ |
||||
while (ctx->buf_ptr < ctx->buf_end - 1) { |
||||
if (*ctx->buf_ptr == 0xFF && *(ctx->buf_ptr + 1) & 0xF0 == 0xF0) |
||||
break; |
||||
ctx->buf_ptr++; |
||||
} |
||||
|
||||
if (ctx->buf_ptr >= ctx->buf_end - 1) |
||||
return -1; |
||||
|
||||
frame->data = (uint8_t*)ctx->buf_ptr; |
||||
|
||||
ret = avpriv_adts_header_parse (&adts_hdr, frame->data, ctx->buf_end - frame->data); |
||||
if (ret < 0) |
||||
return ret; |
||||
|
||||
frame->header_length = adts_hdr->crc_absent ? AV_AAC_ADTS_HEADER_SIZE : AV_AAC_ADTS_HEADER_SIZE + 2; |
||||
frame->length = adts_hdr->frame_length; |
||||
|
||||
av_free(adts_hdr); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int get_next_ac3_eac3_sync_frame(CodecParserContext *ctx, AudioFrame *frame) |
||||
{ |
||||
int ret = 0; |
||||
|
||||
AC3HeaderInfo *hdr = NULL; |
||||
|
||||
/* Find next sync word 0x0B77 */ |
||||
while (ctx->buf_ptr < ctx->buf_end - 1) { |
||||
if (*ctx->buf_ptr == 0x0B && *(ctx->buf_ptr + 1) == 0x77) |
||||
break; |
||||
ctx->buf_ptr++; |
||||
} |
||||
|
||||
if (ctx->buf_ptr >= ctx->buf_end - 1) |
||||
return -1; |
||||
|
||||
frame->data = (uint8_t*)ctx->buf_ptr; |
||||
frame->header_length = 0; |
||||
|
||||
ret = avpriv_ac3_parse_header(&hdr, frame->data, ctx->buf_end - frame->data); |
||||
if (ret < 0) { |
||||
if (ret != AVERROR(ENOMEM)) |
||||
av_free(hdr); |
||||
return ret; |
||||
} |
||||
|
||||
frame->length = hdr->frame_size; |
||||
|
||||
av_free(hdr); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int get_next_sync_frame(enum AVCodecID codec_id, CodecParserContext *ctx, AudioFrame *frame) |
||||
{ |
||||
if (codec_id == AV_CODEC_ID_AAC) |
||||
return get_next_adts_frame(ctx, frame); |
||||
else if (codec_id == AV_CODEC_ID_AC3 || codec_id == AV_CODEC_ID_EAC3) |
||||
return get_next_ac3_eac3_sync_frame(ctx, frame); |
||||
else |
||||
return AVERROR_INVALIDDATA; |
||||
} |
||||
|
||||
static int decrypt_sync_frame(enum AVCodecID codec_id, HLSCryptoContext *crypto_ctx, AudioFrame *frame) |
||||
{ |
||||
int ret = 0; |
||||
uint8_t *data; |
||||
int num_of_encrypted_blocks; |
||||
|
||||
ret = av_aes_init(crypto_ctx->aes_ctx, crypto_ctx->key, 16 * 8, 1); |
||||
if (ret < 0) |
||||
return ret; |
||||
|
||||
data = frame->data + frame->header_length + 16; |
||||
|
||||
num_of_encrypted_blocks = (frame->length - frame->header_length - 16)/16; |
||||
|
||||
av_aes_crypt(crypto_ctx->aes_ctx, data, data, num_of_encrypted_blocks, crypto_ctx->iv, 1); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static int decrypt_audio_frame(enum AVCodecID codec_id, HLSCryptoContext *crypto_ctx, AVPacket *pkt) |
||||
{ |
||||
int ret = 0; |
||||
CodecParserContext ctx; |
||||
AudioFrame frame; |
||||
|
||||
memset(&ctx, 0, sizeof(ctx)); |
||||
ctx.buf_ptr = pkt->data; |
||||
ctx.buf_end = pkt->data + pkt->size; |
||||
|
||||
while (ctx.buf_ptr < ctx.buf_end) { |
||||
memset(&frame, 0, sizeof(frame)); |
||||
ret = get_next_sync_frame(codec_id, &ctx, &frame); |
||||
if (ret < 0) |
||||
return ret; |
||||
if (frame.length - frame.header_length > 31) { |
||||
ret = decrypt_sync_frame(codec_id, crypto_ctx, &frame); |
||||
if (ret < 0) |
||||
return ret; |
||||
} |
||||
ctx.buf_ptr += frame.length; |
||||
} |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
int ff_hls_senc_decrypt_frame(enum AVCodecID codec_id, HLSCryptoContext *crypto_ctx, AVPacket *pkt) |
||||
{ |
||||
if (codec_id == AV_CODEC_ID_H264) |
||||
return decrypt_video_frame(crypto_ctx, pkt); |
||||
else if (codec_id == AV_CODEC_ID_AAC || codec_id == AV_CODEC_ID_AC3 || codec_id == AV_CODEC_ID_EAC3) |
||||
return decrypt_audio_frame(codec_id, crypto_ctx, pkt); |
||||
|
||||
return AVERROR_INVALIDDATA; |
||||
} |
||||
@ -0,0 +1,65 @@ |
||||
/*
|
||||
* Apple HTTP Live Streaming Sample Encryption/Decryption |
||||
* |
||||
* Copyright (c) 2021 Nachiket Tarate |
||||
* |
||||
* This file is part of FFmpeg. |
||||
* |
||||
* FFmpeg 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. |
||||
* |
||||
* FFmpeg 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 FFmpeg; if not, write to the Free Software |
||||
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
||||
*/ |
||||
|
||||
/**
|
||||
* @file |
||||
* Apple HTTP Live Streaming Sample Encryption |
||||
* https://developer.apple.com/library/ios/documentation/AudioVideo/Conceptual/HLS_Sample_Encryption
|
||||
*/ |
||||
|
||||
#ifndef AVFORMAT_HLS_SAMPLE_ENCRYPTION_H |
||||
#define AVFORMAT_HLS_SAMPLE_ENCRYPTION_H |
||||
|
||||
#include <stdint.h> |
||||
|
||||
#include "avformat.h" |
||||
#include "libavcodec/avcodec.h" |
||||
|
||||
#include "libavutil/aes.h" |
||||
|
||||
#define HLS_MAX_ID3_TAGS_DATA_LEN 138 |
||||
#define HLS_MAX_AUDIO_SETUP_DATA_LEN 10 |
||||
|
||||
typedef struct HLSCryptoContext { |
||||
struct AVAES *aes_ctx; |
||||
uint8_t key[16]; |
||||
uint8_t iv[16]; |
||||
} HLSCryptoContext; |
||||
|
||||
typedef struct HLSAudioSetupInfo { |
||||
enum AVCodecID codec_id; |
||||
uint32_t codec_tag; |
||||
uint16_t priming; |
||||
uint8_t version; |
||||
uint8_t setup_data_length; |
||||
uint8_t setup_data[HLS_MAX_AUDIO_SETUP_DATA_LEN]; |
||||
} HLSAudioSetupInfo; |
||||
|
||||
|
||||
void ff_hls_senc_read_audio_setup_info(HLSAudioSetupInfo *info, const uint8_t *buf, size_t size); |
||||
|
||||
int ff_hls_senc_parse_audio_setup_info(AVStream *st, HLSAudioSetupInfo *info); |
||||
|
||||
int ff_hls_senc_decrypt_frame(enum AVCodecID codec_id, HLSCryptoContext *crypto_ctx, AVPacket *pkt); |
||||
|
||||
#endif /* AVFORMAT_HLS_SAMPLE_ENCRYPTION_H */ |
||||
|
||||
Loading…
Reference in new issue