ffmpeg/libavutil/encryption_info.c
Andreas Rheinhardt e6018fda14 avutil/encryption_info: Don't pass NULL to memcpy
The pointer arguments to memcpy (and several other functions of the
C standard library) are not allowed to be NULL, not even when the number
of bytes to copy is zero. An AVEncryptionInitInfo's data pointer is
explicitly allowed to be NULL and yet av_encryption_init_info_add_side_data
unconditionally used it as a source pointer to copy from. This commit changes
this so that copying is only done if the number of bytes to copy is > 0.

Fixes ticket #8141 as well as a part of ticket #8150.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Reviewed-by: Tomas Härdin <tjoppen@acc.umu.se>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2019-09-20 23:26:34 +02:00

342 lines
11 KiB
C

/**
* 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 init_info_count
// {
// 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
// }[init_info_count]
#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_encryption_init_info_free(info->next);
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)
{
// |ret| tracks the front of the list, |info| tracks the back.
AVEncryptionInitInfo *ret = NULL, *info, *temp_info;
uint64_t system_id_size, num_key_ids, key_id_size, data_size, i, j;
uint64_t init_info_count;
if (!side_data || side_data_size < 4)
return NULL;
init_info_count = AV_RB32(side_data);
side_data += 4;
side_data_size -= 4;
for (i = 0; i < init_info_count; i++) {
if (side_data_size < FF_ENCRYPTION_INIT_INFO_EXTRA) {
av_encryption_init_info_free(ret);
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) {
av_encryption_init_info_free(ret);
return NULL;
}
side_data += FF_ENCRYPTION_INIT_INFO_EXTRA;
side_data_size -= FF_ENCRYPTION_INIT_INFO_EXTRA;
temp_info = av_encryption_init_info_alloc(system_id_size, num_key_ids, key_id_size, data_size);
if (!temp_info) {
av_encryption_init_info_free(ret);
return NULL;
}
if (i == 0) {
info = ret = temp_info;
} else {
info->next = temp_info;
info = temp_info;
}
memcpy(info->system_id, side_data, system_id_size);
side_data += system_id_size;
side_data_size -= system_id_size;
for (j = 0; j < num_key_ids; j++) {
memcpy(info->key_ids[j], side_data, key_id_size);
side_data += key_id_size;
side_data_size -= key_id_size;
}
memcpy(info->data, side_data, data_size);
side_data += data_size;
side_data_size -= data_size;
}
return ret;
}
uint8_t *av_encryption_init_info_add_side_data(const AVEncryptionInitInfo *info, size_t *side_data_size)
{
const AVEncryptionInitInfo *cur_info;
uint8_t *buffer, *cur_buffer;
uint32_t i, init_info_count;
uint64_t temp_side_data_size;
temp_side_data_size = 4;
init_info_count = 0;
for (cur_info = info; cur_info; cur_info = cur_info->next) {
temp_side_data_size += (uint64_t)FF_ENCRYPTION_INIT_INFO_EXTRA + cur_info->system_id_size + cur_info->data_size;
if (init_info_count == UINT32_MAX || temp_side_data_size > UINT32_MAX) {
return NULL;
}
init_info_count++;
if (cur_info->num_key_ids) {
temp_side_data_size += (uint64_t)cur_info->num_key_ids * cur_info->key_id_size;
if (temp_side_data_size > UINT32_MAX) {
return NULL;
}
}
}
*side_data_size = temp_side_data_size;
cur_buffer = buffer = av_malloc(*side_data_size);
if (!buffer)
return NULL;
AV_WB32(cur_buffer, init_info_count);
cur_buffer += 4;
for (cur_info = info; cur_info; cur_info = cur_info->next) {
AV_WB32(cur_buffer, cur_info->system_id_size);
AV_WB32(cur_buffer + 4, cur_info->num_key_ids);
AV_WB32(cur_buffer + 8, cur_info->key_id_size);
AV_WB32(cur_buffer + 12, cur_info->data_size);
cur_buffer += 16;
memcpy(cur_buffer, cur_info->system_id, cur_info->system_id_size);
cur_buffer += cur_info->system_id_size;
for (i = 0; i < cur_info->num_key_ids; i++) {
memcpy(cur_buffer, cur_info->key_ids[i], cur_info->key_id_size);
cur_buffer += cur_info->key_id_size;
}
if (cur_info->data_size > 0) {
memcpy(cur_buffer, cur_info->data, cur_info->data_size);
cur_buffer += cur_info->data_size;
}
}
return buffer;
}