mirror of https://github.com/FFmpeg/FFmpeg.git
support writing encrypted mp4 using aes-ctr, conforming to ISO/IEC 23001-7. 3 new parameters were added: - encryption_scheme - allowed values are none (default) and cenc-aes-ctr - encryption_key - 128 bit encryption key (hex) - encryption_kid - 128 bit encryption key identifier (hex) Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>pull/166/head
erankor
9 years ago
committed by
Michael Niedermayer
parent
23ac99dc17
commit
4469e8ebb2
6 changed files with 604 additions and 8 deletions
@ -0,0 +1,415 @@ |
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/*
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* MOV CENC (Common Encryption) writer |
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* Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "movenccenc.h" |
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#include "libavutil/intreadwrite.h" |
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#include "avio_internal.h" |
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#include "movenc.h" |
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#include "avc.h" |
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static int auxiliary_info_alloc_size(MOVMuxCencContext* ctx, int size) |
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{ |
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size_t new_alloc_size; |
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if (ctx->auxiliary_info_size + size > ctx->auxiliary_info_alloc_size) { |
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new_alloc_size = FFMAX(ctx->auxiliary_info_size + size, ctx->auxiliary_info_alloc_size * 2); |
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if (av_reallocp(&ctx->auxiliary_info, new_alloc_size)) { |
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return AVERROR(ENOMEM); |
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} |
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ctx->auxiliary_info_alloc_size = new_alloc_size; |
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} |
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return 0; |
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} |
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static int auxiliary_info_write(MOVMuxCencContext* ctx, |
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const uint8_t *buf_in, int size) |
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{ |
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int ret; |
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ret = auxiliary_info_alloc_size(ctx, size); |
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if (ret) { |
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return ret; |
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} |
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memcpy(ctx->auxiliary_info + ctx->auxiliary_info_size, buf_in, size); |
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ctx->auxiliary_info_size += size; |
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return 0; |
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} |
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static int auxiliary_info_add_subsample(MOVMuxCencContext* ctx, |
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uint16_t clear_bytes, uint32_t encrypted_bytes) |
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{ |
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uint8_t* p; |
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int ret; |
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if (!ctx->use_subsamples) { |
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return 0; |
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} |
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ret = auxiliary_info_alloc_size(ctx, 6); |
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if (ret) { |
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return ret; |
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} |
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p = ctx->auxiliary_info + ctx->auxiliary_info_size; |
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AV_WB16(p, clear_bytes); |
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p += sizeof(uint16_t); |
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AV_WB32(p, encrypted_bytes); |
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ctx->auxiliary_info_size += 6; |
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ctx->subsample_count++; |
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return 0; |
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} |
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/**
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* Encrypt the input buffer and write using avio_write |
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*/ |
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static void mov_cenc_write_encrypted(MOVMuxCencContext* ctx, AVIOContext *pb, |
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const uint8_t *buf_in, int size) |
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{ |
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uint8_t chunk[4096]; |
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const uint8_t* cur_pos = buf_in; |
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int size_left = size; |
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int cur_size; |
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while (size_left > 0) { |
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cur_size = FFMIN(size_left, sizeof(chunk)); |
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av_aes_ctr_crypt(ctx->aes_ctr, chunk, cur_pos, cur_size); |
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avio_write(pb, chunk, cur_size); |
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cur_pos += cur_size; |
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size_left -= cur_size; |
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} |
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} |
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/**
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* Start writing a packet |
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*/ |
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static int mov_cenc_start_packet(MOVMuxCencContext* ctx) |
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{ |
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int ret; |
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/* write the iv */ |
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ret = auxiliary_info_write(ctx, av_aes_ctr_get_iv(ctx->aes_ctr), AES_CTR_IV_SIZE); |
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if (ret) { |
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return ret; |
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} |
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if (!ctx->use_subsamples) { |
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return 0; |
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} |
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/* write a zero subsample count */ |
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ctx->auxiliary_info_subsample_start = ctx->auxiliary_info_size; |
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ctx->subsample_count = 0; |
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ret = auxiliary_info_write(ctx, (uint8_t*)&ctx->subsample_count, sizeof(ctx->subsample_count)); |
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if (ret) { |
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return ret; |
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} |
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return 0; |
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} |
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/**
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* Finalize a packet |
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*/ |
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static int mov_cenc_end_packet(MOVMuxCencContext* ctx) |
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{ |
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size_t new_alloc_size; |
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av_aes_ctr_increment_iv(ctx->aes_ctr); |
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if (!ctx->use_subsamples) { |
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ctx->auxiliary_info_entries++; |
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return 0; |
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} |
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/* add the auxiliary info entry size*/ |
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if (ctx->auxiliary_info_entries >= ctx->auxiliary_info_sizes_alloc_size) { |
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new_alloc_size = ctx->auxiliary_info_entries * 2 + 1; |
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if (av_reallocp(&ctx->auxiliary_info_sizes, new_alloc_size)) { |
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return AVERROR(ENOMEM); |
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} |
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ctx->auxiliary_info_sizes_alloc_size = new_alloc_size; |
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} |
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ctx->auxiliary_info_sizes[ctx->auxiliary_info_entries] = |
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AES_CTR_IV_SIZE + ctx->auxiliary_info_size - ctx->auxiliary_info_subsample_start; |
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ctx->auxiliary_info_entries++; |
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/* update the subsample count*/ |
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AV_WB16(ctx->auxiliary_info + ctx->auxiliary_info_subsample_start, ctx->subsample_count); |
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return 0; |
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} |
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int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb, |
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const uint8_t *buf_in, int size) |
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{ |
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int ret; |
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ret = mov_cenc_start_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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ret = auxiliary_info_add_subsample(ctx, 0, size); |
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if (ret) { |
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return ret; |
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} |
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mov_cenc_write_encrypted(ctx, pb, buf_in, size); |
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ret = mov_cenc_end_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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return 0; |
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} |
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int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb, |
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const uint8_t *buf_in, int size) |
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{ |
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const uint8_t *p = buf_in; |
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const uint8_t *end = p + size; |
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const uint8_t *nal_start, *nal_end; |
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int ret; |
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ret = mov_cenc_start_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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size = 0; |
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nal_start = ff_avc_find_startcode(p, end); |
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for (;;) { |
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while (nal_start < end && !*(nal_start++)); |
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if (nal_start == end) |
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break; |
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nal_end = ff_avc_find_startcode(nal_start, end); |
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avio_wb32(pb, nal_end - nal_start); |
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avio_w8(pb, *nal_start); |
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mov_cenc_write_encrypted(ctx, pb, nal_start + 1, nal_end - nal_start - 1); |
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auxiliary_info_add_subsample(ctx, 5, nal_end - nal_start - 1); |
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size += 4 + nal_end - nal_start; |
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nal_start = nal_end; |
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} |
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ret = mov_cenc_end_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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return size; |
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} |
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int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx, |
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int nal_length_size, AVIOContext *pb, const uint8_t *buf_in, int size) |
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{ |
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int nalsize; |
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int ret; |
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int j; |
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ret = mov_cenc_start_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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while (size > 0) { |
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/* parse the nal size */ |
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if (size < nal_length_size + 1) { |
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av_log(s, AV_LOG_ERROR, "CENC-AVC: remaining size %d smaller than nal length+type %d\n", |
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size, nal_length_size + 1); |
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return -1; |
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} |
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avio_write(pb, buf_in, nal_length_size + 1); |
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nalsize = 0; |
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for (j = 0; j < nal_length_size; j++) { |
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nalsize = (nalsize << 8) | *buf_in++; |
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} |
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size -= nal_length_size; |
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/* encrypt the nal body */ |
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if (nalsize <= 0 || nalsize > size) { |
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av_log(s, AV_LOG_ERROR, "CENC-AVC: nal size %d remaining %d\n", nalsize, size); |
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return -1; |
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} |
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mov_cenc_write_encrypted(ctx, pb, buf_in + 1, nalsize - 1); |
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buf_in += nalsize; |
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size -= nalsize; |
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auxiliary_info_add_subsample(ctx, nal_length_size + 1, nalsize - 1); |
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} |
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ret = mov_cenc_end_packet(ctx); |
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if (ret) { |
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return ret; |
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} |
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return 0; |
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} |
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/* TODO: reuse this function from movenc.c */ |
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static int64_t update_size(AVIOContext *pb, int64_t pos) |
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{ |
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int64_t curpos = avio_tell(pb); |
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avio_seek(pb, pos, SEEK_SET); |
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avio_wb32(pb, curpos - pos); /* rewrite size */ |
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avio_seek(pb, curpos, SEEK_SET); |
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return curpos - pos; |
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} |
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static int mov_cenc_write_senc_tag(MOVMuxCencContext* ctx, AVIOContext *pb, |
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int64_t* auxiliary_info_offset) |
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{ |
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int64_t pos = avio_tell(pb); |
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avio_wb32(pb, 0); /* size */ |
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ffio_wfourcc(pb, "senc"); |
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avio_wb32(pb, ctx->use_subsamples ? 0x02 : 0); /* version & flags */ |
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avio_wb32(pb, ctx->auxiliary_info_entries); /* entry count */ |
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*auxiliary_info_offset = avio_tell(pb); |
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avio_write(pb, ctx->auxiliary_info, ctx->auxiliary_info_size); |
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return update_size(pb, pos); |
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} |
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static int mov_cenc_write_saio_tag(AVIOContext *pb, int64_t auxiliary_info_offset) |
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{ |
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int64_t pos = avio_tell(pb); |
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uint8_t version; |
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avio_wb32(pb, 0); /* size */ |
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ffio_wfourcc(pb, "saio"); |
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version = auxiliary_info_offset > 0xffffffff ? 1 : 0; |
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avio_w8(pb, version); |
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avio_wb24(pb, 0); /* flags */ |
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avio_wb32(pb, 1); /* entry count */ |
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if (version) { |
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avio_wb64(pb, auxiliary_info_offset); |
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} else { |
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avio_wb32(pb, auxiliary_info_offset); |
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} |
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return update_size(pb, pos); |
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} |
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static int mov_cenc_write_saiz_tag(MOVMuxCencContext* ctx, AVIOContext *pb) |
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{ |
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int64_t pos = avio_tell(pb); |
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avio_wb32(pb, 0); /* size */ |
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ffio_wfourcc(pb, "saiz"); |
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avio_wb32(pb, 0); /* version & flags */ |
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avio_w8(pb, ctx->use_subsamples ? 0 : AES_CTR_IV_SIZE); /* default size*/ |
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avio_wb32(pb, ctx->auxiliary_info_entries); /* entry count */ |
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if (ctx->use_subsamples) { |
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avio_write(pb, ctx->auxiliary_info_sizes, ctx->auxiliary_info_entries); |
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} |
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return update_size(pb, pos); |
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} |
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void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb) |
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{ |
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int64_t auxiliary_info_offset; |
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mov_cenc_write_senc_tag(ctx, pb, &auxiliary_info_offset); |
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mov_cenc_write_saio_tag(pb, auxiliary_info_offset); |
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mov_cenc_write_saiz_tag(ctx, pb); |
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} |
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static int mov_cenc_write_schi_tag(AVIOContext *pb, uint8_t* kid) |
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{ |
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int64_t pos = avio_tell(pb); |
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avio_wb32(pb, 0); /* size */ |
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ffio_wfourcc(pb, "schi"); |
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avio_wb32(pb, 32); /* size */ |
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ffio_wfourcc(pb, "tenc"); |
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avio_wb32(pb, 0); /* version & flags */ |
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avio_wb24(pb, 1); /* is encrypted */ |
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avio_w8(pb, AES_CTR_IV_SIZE); /* iv size */ |
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avio_write(pb, kid, CENC_KID_SIZE); |
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return update_size(pb, pos); |
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} |
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int ff_mov_cenc_write_sinf_tag(MOVTrack* track, AVIOContext *pb, uint8_t* kid) |
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{ |
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int64_t pos = avio_tell(pb); |
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avio_wb32(pb, 0); /* size */ |
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ffio_wfourcc(pb, "sinf"); |
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/* frma */ |
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avio_wb32(pb, 12); /* size */ |
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ffio_wfourcc(pb, "frma"); |
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avio_wl32(pb, track->tag); |
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/* schm */ |
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avio_wb32(pb, 20); /* size */ |
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ffio_wfourcc(pb, "schm"); |
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avio_wb32(pb, 0); /* version & flags */ |
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ffio_wfourcc(pb, "cenc"); /* scheme type*/ |
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avio_wb32(pb, 0x10000); /* scheme version */ |
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/* schi */ |
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mov_cenc_write_schi_tag(pb, kid); |
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return update_size(pb, pos); |
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} |
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int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key, |
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int use_subsamples, int bitexact) |
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{ |
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int ret; |
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ctx->aes_ctr = av_aes_ctr_alloc(); |
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if (!ctx->aes_ctr) { |
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return AVERROR(ENOMEM); |
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} |
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ret = av_aes_ctr_init(ctx->aes_ctr, encryption_key); |
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if (ret != 0) { |
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return ret; |
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} |
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if (!bitexact) { |
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av_aes_ctr_set_random_iv(ctx->aes_ctr); |
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} |
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ctx->use_subsamples = use_subsamples; |
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return 0; |
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} |
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void ff_mov_cenc_free(MOVMuxCencContext* ctx) |
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{ |
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av_aes_ctr_free(ctx->aes_ctr); |
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} |
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@ -0,0 +1,86 @@ |
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/*
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* MOV CENC (Common Encryption) writer |
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* Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVFORMAT_MOVENCCENC_H |
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#define AVFORMAT_MOVENCCENC_H |
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#include "libavutil/aes_ctr.h" |
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#include "avformat.h" |
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#include "avio.h" |
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#define CENC_KID_SIZE (16) |
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struct MOVTrack; |
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typedef struct { |
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struct AVAESCTR* aes_ctr; |
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uint8_t* auxiliary_info; |
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size_t auxiliary_info_size; |
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size_t auxiliary_info_alloc_size; |
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uint32_t auxiliary_info_entries; |
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/* subsample support */ |
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int use_subsamples; |
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uint16_t subsample_count; |
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size_t auxiliary_info_subsample_start; |
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uint8_t* auxiliary_info_sizes; |
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size_t auxiliary_info_sizes_alloc_size; |
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} MOVMuxCencContext; |
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/**
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* Initialize a CENC context |
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* @param key encryption key, must have a length of AES_CTR_KEY_SIZE |
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* @param use_subsamples when enabled parts of a packet can be encrypted, otherwise the whole packet is encrypted |
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*/ |
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int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key, int use_subsamples, int bitexact); |
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/**
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* Free a CENC context |
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*/ |
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void ff_mov_cenc_free(MOVMuxCencContext* ctx); |
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/**
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* Write a fully encrypted packet |
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*/ |
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int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size); |
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|
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/**
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* Parse AVC NAL units from annex B format, the nal size and type are written in the clear while the body is encrypted |
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*/ |
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int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size); |
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/**
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* Write AVC NAL units that are in MP4 format, the nal size and type are written in the clear while the body is encrypted |
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*/ |
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int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx, int nal_length_size, |
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AVIOContext *pb, const uint8_t *buf_in, int size); |
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/**
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* Write the cenc atoms that should reside inside stbl |
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*/ |
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void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb); |
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/**
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* Write the sinf atom, contained inside stsd |
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*/ |
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int ff_mov_cenc_write_sinf_tag(struct MOVTrack* track, AVIOContext *pb, uint8_t* kid); |
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#endif /* AVFORMAT_MOVENCCENC_H */ |
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