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avcodec/avcodec.h: Add encryption info side data.

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This new side-data will contain info on how a packet is encrypted.
This allows the app to handle packet decryption.

Signed-off-by: Jacob Trimble <modmaker@google.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
pull/283/head
Jacob Trimble 7 years ago committed by Michael Niedermayer
parent 829aebf95d
commit db2a7c947e
6 changed files with 515 additions and 1 deletions
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  1. 4
      doc/APIchanges
  2. 13
      libavcodec/avcodec.h
  3. 2
      libavutil/Makefile
  4. 295
      libavutil/encryption_info.c
  5. 200
      libavutil/encryption_info.h
  6. 2
      libavutil/version.h

4
doc/APIchanges
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@ -15,6 +15,10 @@ libavutil: 2017-10-21
API changes, most recent first:
2018-xx-xx - xxxxxxx - lavu 56.8.100 - encryption_info.h
Add AVEncryptionInitInfo and AVEncryptionInfo structures to hold new side-data
for encryption info.
2018-03-21 - xxxxxxx - lavc 58.15.100 - avcodec.h
Add av_packet_make_writable().

13
libavcodec/avcodec.h
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@ -1344,6 +1344,19 @@ enum AVPacketSideDataType {
*/
AV_PKT_DATA_A53_CC,
/**
* This side data is encryption initialization data.
* The format is not part of ABI, use av_encryption_init_info_* methods to
* access.
*/
AV_PKT_DATA_ENCRYPTION_INIT_INFO,
/**
* This side data contains encryption info for how to decrypt the packet.
* The format is not part of ABI, use av_encryption_info_* methods to access.
*/
AV_PKT_DATA_ENCRYPTION_INFO,
/**
* The number of side data types.
* This is not part of the public API/ABI in the sense that it may

2
libavutil/Makefile
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@ -24,6 +24,7 @@ HEADERS = adler32.h \
dict.h \
display.h \
downmix_info.h \
encryption_info.h \
error.h \
eval.h \
fifo.h \
@ -107,6 +108,7 @@ OBJS = adler32.o \
dict.o \
display.o \
downmix_info.o \
encryption_info.o \
error.o \
eval.o \
fifo.o \

295
libavutil/encryption_info.c
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@ -0,0 +1,295 @@
/**
* 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
*/
#include "encryption_info.h"
#include "mem.h"
#include "intreadwrite.h"
#define FF_ENCRYPTION_INFO_EXTRA 24
// The format of the AVEncryptionInfo side data:
// u32be scheme
// u32be crypt_byte_block
// u32be skip_byte_block
// u32be key_id_size
// u32be iv_size
// u32be subsample_count
// u8[key_id_size] key_id
// u8[iv_size] iv
// {
// u32be bytes_of_clear_data
// u32be bytes_of_protected_data
// }[subsample_count]
AVEncryptionInfo *av_encryption_info_alloc(uint32_t subsample_count, uint32_t key_id_size, uint32_t iv_size)
{
AVEncryptionInfo *info;
info = av_mallocz(sizeof(*info));
if (!info)
return NULL;
info->key_id = av_mallocz(key_id_size);
info->key_id_size = key_id_size;
info->iv = av_mallocz(iv_size);
info->iv_size = iv_size;
info->subsamples = av_mallocz_array(subsample_count, sizeof(*info->subsamples));
info->subsample_count = subsample_count;
// Allow info->subsamples to be NULL if there are no subsamples.
if (!info->key_id || !info->iv || (!info->subsamples && subsample_count)) {
av_encryption_info_free(info);
return NULL;
}
return info;
}
AVEncryptionInfo *av_encryption_info_clone(const AVEncryptionInfo *info)
{
AVEncryptionInfo *ret;
ret = av_encryption_info_alloc(info->subsample_count, info->key_id_size, info->iv_size);
if (!ret)
return NULL;
ret->scheme = info->scheme;
ret->crypt_byte_block = info->crypt_byte_block;
ret->skip_byte_block = info->skip_byte_block;
memcpy(ret->iv, info->iv, info->iv_size);
memcpy(ret->key_id, info->key_id, info->key_id_size);
memcpy(ret->subsamples, info->subsamples, sizeof(*info->subsamples) * info->subsample_count);
return ret;
}
void av_encryption_info_free(AVEncryptionInfo *info)
{
if (info) {
av_free(info->key_id);
av_free(info->iv);
av_free(info->subsamples);
av_free(info);
}
}
AVEncryptionInfo *av_encryption_info_get_side_data(const uint8_t* buffer, size_t size)
{
AVEncryptionInfo *info;
uint64_t key_id_size, iv_size, subsample_count, i;
if (!buffer || size < FF_ENCRYPTION_INFO_EXTRA)
return NULL;
key_id_size = AV_RB32(buffer + 12);
iv_size = AV_RB32(buffer + 16);
subsample_count = AV_RB32(buffer + 20);
if (size < FF_ENCRYPTION_INFO_EXTRA + key_id_size + iv_size + subsample_count * 8)
return NULL;
info = av_encryption_info_alloc(subsample_count, key_id_size, iv_size);
if (!info)
return NULL;
info->scheme = AV_RB32(buffer);
info->crypt_byte_block = AV_RB32(buffer + 4);
info->skip_byte_block = AV_RB32(buffer + 8);
memcpy(info->key_id, buffer + 24, key_id_size);
memcpy(info->iv, buffer + key_id_size + 24, iv_size);
buffer += key_id_size + iv_size + 24;
for (i = 0; i < subsample_count; i++) {
info->subsamples[i].bytes_of_clear_data = AV_RB32(buffer);
info->subsamples[i].bytes_of_protected_data = AV_RB32(buffer + 4);
buffer += 8;
}
return info;
}
uint8_t *av_encryption_info_add_side_data(const AVEncryptionInfo *info, size_t *size)
{
uint8_t *buffer, *cur_buffer;
uint32_t i;
if (UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA < info->key_id_size ||
UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA - info->key_id_size < info->iv_size ||
(UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA - info->key_id_size - info->iv_size) / 8 < info->subsample_count) {
return NULL;
}
*size = FF_ENCRYPTION_INFO_EXTRA + info->key_id_size + info->iv_size +
(info->subsample_count * 8);
cur_buffer = buffer = av_malloc(*size);
if (!buffer)
return NULL;
AV_WB32(cur_buffer, info->scheme);
AV_WB32(cur_buffer + 4, info->crypt_byte_block);
AV_WB32(cur_buffer + 8, info->skip_byte_block);
AV_WB32(cur_buffer + 12, info->key_id_size);
AV_WB32(cur_buffer + 16, info->iv_size);
AV_WB32(cur_buffer + 20, info->subsample_count);
cur_buffer += 24;
memcpy(cur_buffer, info->key_id, info->key_id_size);
cur_buffer += info->key_id_size;
memcpy(cur_buffer, info->iv, info->iv_size);
cur_buffer += info->iv_size;
for (i = 0; i < info->subsample_count; i++) {
AV_WB32(cur_buffer, info->subsamples[i].bytes_of_clear_data);
AV_WB32(cur_buffer + 4, info->subsamples[i].bytes_of_protected_data);
cur_buffer += 8;
}
return buffer;
}
// The format of the AVEncryptionInitInfo side data:
// u32be system_id_size
// u32be num_key_ids
// u32be key_id_size
// u32be data_size
// u8[system_id_size] system_id
// u8[key_id_size][num_key_id] key_ids
// u8[data_size] data
#define FF_ENCRYPTION_INIT_INFO_EXTRA 16
AVEncryptionInitInfo *av_encryption_init_info_alloc(
uint32_t system_id_size, uint32_t num_key_ids, uint32_t key_id_size, uint32_t data_size)
{
AVEncryptionInitInfo *info;
uint32_t i;
info = av_mallocz(sizeof(*info));
if (!info)
return NULL;
info->system_id = av_mallocz(system_id_size);
info->system_id_size = system_id_size;
info->key_ids = key_id_size ? av_mallocz_array(num_key_ids, sizeof(*info->key_ids)) : NULL;
info->num_key_ids = num_key_ids;
info->key_id_size = key_id_size;
info->data = av_mallocz(data_size);
info->data_size = data_size;
// Allow pointers to be NULL if the size is 0.
if ((!info->system_id && system_id_size) || (!info->data && data_size) ||
(!info->key_ids && num_key_ids && key_id_size)) {
av_encryption_init_info_free(info);
return NULL;
}
if (key_id_size) {
for (i = 0; i < num_key_ids; i++) {
info->key_ids[i] = av_mallocz(key_id_size);
if (!info->key_ids[i]) {
av_encryption_init_info_free(info);
return NULL;
}
}
}
return info;
}
void av_encryption_init_info_free(AVEncryptionInitInfo *info)
{
uint32_t i;
if (info) {
for (i = 0; i < info->num_key_ids; i++) {
av_free(info->key_ids[i]);
}
av_free(info->system_id);
av_free(info->key_ids);
av_free(info->data);
av_free(info);
}
}
AVEncryptionInitInfo *av_encryption_init_info_get_side_data(
const uint8_t *side_data, size_t side_data_size)
{
AVEncryptionInitInfo *info;
uint64_t system_id_size, num_key_ids, key_id_size, data_size, i;
if (!side_data || side_data_size < FF_ENCRYPTION_INIT_INFO_EXTRA)
return NULL;
system_id_size = AV_RB32(side_data);
num_key_ids = AV_RB32(side_data + 4);
key_id_size = AV_RB32(side_data + 8);
data_size = AV_RB32(side_data + 12);
// UINT32_MAX + UINT32_MAX + UINT32_MAX * UINT32_MAX == UINT64_MAX
if (side_data_size - FF_ENCRYPTION_INIT_INFO_EXTRA < system_id_size + data_size + num_key_ids * key_id_size)
return NULL;
info = av_encryption_init_info_alloc(system_id_size, num_key_ids, key_id_size, data_size);
if (!info)
return NULL;
memcpy(info->system_id, side_data + 16, system_id_size);
side_data += system_id_size + 16;
for (i = 0; i < num_key_ids; i++) {
memcpy(info->key_ids[i], side_data, key_id_size);
side_data += key_id_size;
}
memcpy(info->data, side_data, data_size);
return info;
}
uint8_t *av_encryption_init_info_add_side_data(const AVEncryptionInitInfo *info, size_t *side_data_size)
{
uint8_t *buffer, *cur_buffer;
uint32_t i, max_size;
if (UINT32_MAX - FF_ENCRYPTION_INIT_INFO_EXTRA < info->system_id_size ||
UINT32_MAX - FF_ENCRYPTION_INIT_INFO_EXTRA - info->system_id_size < info->data_size) {
return NULL;
}
if (info->num_key_ids) {
max_size = UINT32_MAX - FF_ENCRYPTION_INIT_INFO_EXTRA - info->system_id_size - info->data_size;
if (max_size / info->num_key_ids < info->key_id_size)
return NULL;
}
*side_data_size = FF_ENCRYPTION_INIT_INFO_EXTRA + info->system_id_size +
info->data_size + (info->num_key_ids * info->key_id_size);
cur_buffer = buffer = av_malloc(*side_data_size);
if (!buffer)
return NULL;
AV_WB32(cur_buffer, info->system_id_size);
AV_WB32(cur_buffer + 4, info->num_key_ids);
AV_WB32(cur_buffer + 8, info->key_id_size);
AV_WB32(cur_buffer + 12, info->data_size);
cur_buffer += 16;
memcpy(cur_buffer, info->system_id, info->system_id_size);
cur_buffer += info->system_id_size;
for (i = 0; i < info->num_key_ids; i++) {
memcpy(cur_buffer, info->key_ids[i], info->key_id_size);
cur_buffer += info->key_id_size;
}
memcpy(cur_buffer, info->data, info->data_size);
return buffer;
}

200
libavutil/encryption_info.h
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@ -0,0 +1,200 @@
/**
* 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
*/
#ifndef AVUTIL_ENCRYPTION_INFO_H
#define AVUTIL_ENCRYPTION_INFO_H
#include <stddef.h>
#include <stdint.h>
typedef struct AVSubsampleEncryptionInfo {
/** The number of bytes that are clear. */
unsigned int bytes_of_clear_data;
/**
* The number of bytes that are protected. If using pattern encryption,
* the pattern applies to only the protected bytes; if not using pattern
* encryption, all these bytes are encrypted.
*/
unsigned int bytes_of_protected_data;
} AVSubsampleEncryptionInfo;
/**
* This describes encryption info for a packet. This contains frame-specific
* info for how to decrypt the packet before passing it to the decoder.
*
* The size of this struct is not part of the public ABI.
*/
typedef struct AVEncryptionInfo {
/** The fourcc encryption scheme. */
uint32_t scheme;
/**
* Only used for pattern encryption. This is the number of 16-byte blocks
* that are encrypted.
*/
uint32_t crypt_byte_block;
/**
* Only used for pattern encryption. This is the number of 16-byte blocks
* that are clear.
*/
uint32_t skip_byte_block;
/**
* The ID of the key used to encrypt the packet. This should always be
* 16 bytes long, but may be changed in the future.
*/
uint8_t *key_id;
uint32_t key_id_size;
/**
* The initialization vector. This may have been zero-filled to be the
* correct block size. This should always be 16 bytes long, but may be
* changed in the future.
*/
uint8_t *iv;
uint32_t iv_size;
/**
* An array of subsample encryption info specifying how parts of the sample
* are encrypted. If there are no subsamples, then the whole sample is
* encrypted.
*/
AVSubsampleEncryptionInfo *subsamples;
uint32_t subsample_count;
} AVEncryptionInfo;
/**
* This describes info used to initialize an encryption key system.
*
* The size of this struct is not part of the public ABI.
*/
typedef struct AVEncryptionInitInfo {
/**
* A unique identifier for the key system this is for, can be NULL if it
* is not known. This should always be 16 bytes, but may change in the
* future.
*/
uint8_t* system_id;
uint32_t system_id_size;
/**
* An array of key IDs this initialization data is for. All IDs are the
* same length. Can be NULL if there are no known key IDs.
*/
uint8_t** key_ids;
/** The number of key IDs. */
uint32_t num_key_ids;
/**
* The number of bytes in each key ID. This should always be 16, but may
* change in the future.
*/
uint32_t key_id_size;
/**
* Key-system specific initialization data. This data is copied directly
* from the file and the format depends on the specific key system. This
* can be NULL if there is no initialization data; in that case, there
* will be at least one key ID.
*/
uint8_t* data;
uint32_t data_size;
} AVEncryptionInitInfo;
/**
* Allocates an AVEncryptionInfo structure and sub-pointers to hold the given
* number of subsamples. This will allocate pointers for the key ID, IV,
* and subsample entries, set the size members, and zero-initialize the rest.
*
* @param subsample_count The number of subsamples.
* @param key_id_size The number of bytes in the key ID, should be 16.
* @param key_id_size The number of bytes in the IV, should be 16.
*
* @return The new AVEncryptionInfo structure, or NULL on error.
*/
AVEncryptionInfo *av_encryption_info_alloc(uint32_t subsample_count, uint32_t key_id_size, uint32_t iv_size);
/**
* Allocates an AVEncryptionInfo structure with a copy of the given data.
* @return The new AVEncryptionInfo structure, or NULL on error.
*/
AVEncryptionInfo *av_encryption_info_clone(const AVEncryptionInfo *info);
/**
* Frees the given encryption info object. This MUST NOT be used to free the
* side-data data pointer, that should use normal side-data methods.
*/
void av_encryption_info_free(AVEncryptionInfo *info);
/**
* Creates a copy of the AVEncryptionInfo that is contained in the given side
* data. The resulting object should be passed to av_encryption_info_free()
* when done.
*
* @return The new AVEncryptionInfo structure, or NULL on error.
*/
AVEncryptionInfo *av_encryption_info_get_side_data(const uint8_t *side_data, size_t side_data_size);
/**
* Allocates and initializes side data that holds a copy of the given encryption
* info. The resulting pointer should be either freed using av_free or given
* to av_packet_add_side_data().
*
* @return The new side-data pointer, or NULL.
*/
uint8_t *av_encryption_info_add_side_data(
const AVEncryptionInfo *info, size_t *side_data_size);
/**
* Allocates an AVEncryptionInitInfo structure and sub-pointers to hold the
* given sizes. This will allocate pointers and set all the fields.
*
* @return The new AVEncryptionInitInfo structure, or NULL on error.
*/
AVEncryptionInitInfo *av_encryption_init_info_alloc(
uint32_t system_id_size, uint32_t num_key_ids, uint32_t key_id_size, uint32_t data_size);
/**
* Frees the given encryption init info object. This MUST NOT be used to free
* the side-data data pointer, that should use normal side-data methods.
*/
void av_encryption_init_info_free(AVEncryptionInitInfo* info);
/**
* Creates a copy of the AVEncryptionInitInfo that is contained in the given
* side data. The resulting object should be passed to
* av_encryption_init_info_free() when done.
*
* @return The new AVEncryptionInitInfo structure, or NULL on error.
*/
AVEncryptionInitInfo *av_encryption_init_info_get_side_data(
const uint8_t* side_data, size_t side_data_size);
/**
* Allocates and initializes side data that holds a copy of the given encryption
* init info. The resulting pointer should be either freed using av_free or
* given to av_packet_add_side_data().
*
* @return The new side-data pointer, or NULL.
*/
uint8_t *av_encryption_init_info_add_side_data(
const AVEncryptionInitInfo *info, size_t *side_data_size);
#endif /* AVUTIL_ENCRYPTION_INFO_H */

2
libavutil/version.h
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@ -79,7 +79,7 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 56
#define LIBAVUTIL_VERSION_MINOR 11
#define LIBAVUTIL_VERSION_MINOR 12
#define LIBAVUTIL_VERSION_MICRO 100
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

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