86 lines
2.7 KiB
C++
86 lines
2.7 KiB
C++
|
// Copyright 2016 Google Inc. All rights reserved.
|
||
|
|
//
|
||
|
|
// Use of this source code is governed by a BSD-style
|
||
|
|
// license that can be found in the LICENSE file or at
|
||
|
|
// https://developers.google.com/open-source/licenses/bsd
|
||
|
|
|
||
|
|
#include "packager/media/base/decryptor_source.h"
|
||
|
|
|
||
|
|
#include "packager/base/logging.h"
|
||
|
|
#include "packager/base/stl_util.h"
|
||
|
|
|
||
|
|
namespace edash_packager {
|
||
|
|
namespace media {
|
||
|
|
|
||
|
|
DecryptorSource::DecryptorSource(KeySource* key_source)
|
||
|
|
: key_source_(key_source) {
|
||
|
|
CHECK(key_source);
|
||
|
|
}
|
||
|
|
DecryptorSource::~DecryptorSource() {
|
||
|
|
STLDeleteValues(&decryptor_map_);
|
||
|
|
}
|
||
|
|
|
||
|
|
bool DecryptorSource::DecryptSampleBuffer(const DecryptConfig* decrypt_config,
|
||
|
|
uint8_t* buffer,
|
||
|
|
size_t buffer_size) {
|
||
|
|
DCHECK(decrypt_config);
|
||
|
|
DCHECK(buffer);
|
||
|
|
|
||
|
|
// Get the decryptor object.
|
||
|
|
AesCtrEncryptor* decryptor;
|
||
|
|
auto found = decryptor_map_.find(decrypt_config->key_id());
|
||
|
|
if (found == decryptor_map_.end()) {
|
||
|
|
// Create new AesCtrEncryptor
|
||
|
|
EncryptionKey key;
|
||
|
|
Status status(key_source_->GetKey(decrypt_config->key_id(), &key));
|
||
|
|
if (!status.ok()) {
|
||
|
|
LOG(ERROR) << "Error retrieving decryption key: " << status;
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
scoped_ptr<AesCtrEncryptor> aes_ctr_encryptor(new AesCtrEncryptor);
|
||
|
|
if (!aes_ctr_encryptor->InitializeWithIv(key.key, decrypt_config->iv())) {
|
||
|
|
LOG(ERROR) << "Failed to initialize AesCtrEncryptor for decryption.";
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
decryptor = aes_ctr_encryptor.release();
|
||
|
|
decryptor_map_[decrypt_config->key_id()] = decryptor;
|
||
|
|
} else {
|
||
|
|
decryptor = found->second;
|
||
|
|
}
|
||
|
|
if (!decryptor->SetIv(decrypt_config->iv())) {
|
||
|
|
LOG(ERROR) << "Invalid initialization vector.";
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (decrypt_config->subsamples().empty()) {
|
||
|
|
// Sample not encrypted using subsample encryption. Decrypt whole.
|
||
|
|
if (!decryptor->Decrypt(buffer, buffer_size, buffer)) {
|
||
|
|
LOG(ERROR) << "Error during bulk sample decryption.";
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Subsample decryption.
|
||
|
|
const std::vector<SubsampleEntry>& subsamples = decrypt_config->subsamples();
|
||
|
|
uint8_t* current_ptr = buffer;
|
||
|
|
const uint8_t* const buffer_end = buffer + buffer_size;
|
||
|
|
for (const auto& subsample : subsamples) {
|
||
|
|
if ((current_ptr + subsample.clear_bytes + subsample.cipher_bytes) >
|
||
|
|
buffer_end) {
|
||
|
|
LOG(ERROR) << "Subsamples overflow sample buffer.";
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
current_ptr += subsample.clear_bytes;
|
||
|
|
if (!decryptor->Decrypt(current_ptr, subsample.cipher_bytes, current_ptr)) {
|
||
|
|
LOG(ERROR) << "Error decrypting subsample buffer.";
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
current_ptr += subsample.cipher_bytes;
|
||
|
|
}
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
} // namespace media
|
||
|
|
} // namespace edash_packager
|