81 lines
2.6 KiB
C++
81 lines
2.6 KiB
C++
// Copyright 2016 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#include "packager/media/base/aes_cryptor.h"
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#include <openssl/aes.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include "packager/base/logging.h"
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#include "packager/base/stl_util.h"
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namespace edash_packager {
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namespace media {
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AesCryptor::AesCryptor() : aes_key_(new AES_KEY) {}
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AesCryptor::~AesCryptor() {}
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bool AesCryptor::Crypt(const std::vector<uint8_t>& text,
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std::vector<uint8_t>* crypt_text) {
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// Save text size to make it work for in-place conversion, since the
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// next statement will update the text size.
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const size_t text_size = text.size();
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crypt_text->resize(text_size + NumPaddingBytes(text_size));
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size_t crypt_text_size = crypt_text->size();
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if (!CryptInternal(text.data(), text_size, crypt_text->data(),
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&crypt_text_size)) {
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return false;
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}
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DCHECK_LE(crypt_text_size, crypt_text->size());
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crypt_text->resize(crypt_text_size);
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return true;
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}
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bool AesCryptor::Crypt(const std::string& text, std::string* crypt_text) {
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// Save text size to make it work for in-place conversion, since the
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// next statement will update the text size.
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const size_t text_size = text.size();
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crypt_text->resize(text_size + NumPaddingBytes(text_size));
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size_t crypt_text_size = crypt_text->size();
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if (!CryptInternal(reinterpret_cast<const uint8_t*>(text.data()), text_size,
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reinterpret_cast<uint8_t*>(string_as_array(crypt_text)),
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&crypt_text_size))
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return false;
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DCHECK_LE(crypt_text_size, crypt_text->size());
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crypt_text->resize(crypt_text_size);
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return true;
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}
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size_t AesCryptor::NumPaddingBytes(size_t size) const {
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// No padding by default.
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return 0;
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}
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bool AesCryptor::GenerateRandomIv(FourCC protection_scheme,
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std::vector<uint8_t>* iv) {
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// ISO/IEC 23001-7:2016 10.1 and 10.3 For 'cenc' and 'cens'
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// default_Per_Sample_IV_Size and Per_Sample_IV_Size SHOULD be 8-bytes.
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// There is no official guideline on the iv size for 'cbc1' and 'cbcs',
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// but 16-byte provides better security.
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const size_t iv_size =
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(protection_scheme == FOURCC_cenc || protection_scheme == FOURCC_cens)
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? 8
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: 16;
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iv->resize(iv_size);
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if (RAND_bytes(iv->data(), iv_size) != 1) {
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LOG(ERROR) << "RAND_bytes failed with error: "
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<< ERR_error_string(ERR_get_error(), NULL);
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return false;
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}
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return true;
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}
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} // namespace media
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} // namespace edash_packager
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