e51c9fbbb8
Merge from Widevine repo of http://go/wvgerrit/121950 Remove term "Master" from "Widevine Master License Agreement". Bug: 168562298 Change-Id: I655babf1bc447f4872f6a0f849107262be42df7a
94 lines
3.5 KiB
C++
94 lines
3.5 KiB
C++
// Copyright 2019 Google LLC. All Rights Reserved. This file and proprietary
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// source code may only be used and distributed under the Widevine
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// License Agreement.
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//
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#ifndef CDM_OEC_KEY_DERIVER_H_
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#define CDM_OEC_KEY_DERIVER_H_
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#include <openssl/aes.h>
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#include <openssl/rsa.h>
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#include <time.h>
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#include <string>
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#include <vector>
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#include "oec_device_features.h"
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#include "oemcrypto_types.h"
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#include "pst_report.h"
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namespace wvoec {
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constexpr size_t kMaxTestRSAKeyLength = 2000; // Rough estimate.
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constexpr size_t kMaxCoreProvRequest = 150; // Rough estimate.
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// This structure will be signed to simulate a provisioning response from the
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// server.
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struct RSAPrivateKeyMessage {
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uint8_t rsa_key[kMaxTestRSAKeyLength];
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uint8_t rsa_key_iv[KEY_IV_SIZE];
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size_t rsa_key_length;
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uint8_t enc_message_key[kMaxTestRSAKeyLength];
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size_t enc_message_key_length;
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uint32_t nonce;
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};
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// Holds an encryption key and can encrypt a provisioning message. It also can
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// encrypt short buffers using CBC, such as content keys in a license.
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class Encryptor {
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public:
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Encryptor() : enc_key_(KEY_SIZE, 0) {}
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Encryptor(const std::vector<uint8_t>& enc_key) { set_enc_key(enc_key); };
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Encryptor& operator=(const Encryptor&) = default;
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void set_enc_key(const std::vector<uint8_t>& enc_key);
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// This encrypts an RSAPrivateKeyMessage with encryption_key so that it may be
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// loaded with OEMCrypto_LoadProvisioningResponse.
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// This modifies the clear data: it adds padding and generates a random iv.
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void PadAndEncryptProvisioningMessage(RSAPrivateKeyMessage* data,
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RSAPrivateKeyMessage* encrypted) const;
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void CBCEncrypt(const uint8_t* data, uint8_t* encrypted_data,
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size_t data_length, const uint8_t (&iv)[KEY_IV_SIZE]) const;
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private:
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std::vector<uint8_t> enc_key_;
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};
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// Holds encryption and mac keys derived from a master key.
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// Can be used to sign a buffer as either a server or client.
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class KeyDeriver : public Encryptor {
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public:
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KeyDeriver()
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: mac_key_server_(MAC_KEY_SIZE, 0), mac_key_client_(MAC_KEY_SIZE, 0) {}
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KeyDeriver& operator=(const KeyDeriver&) = default;
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// Generate mac and enc keys give the master key.
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void DeriveKeys(const uint8_t* master_key,
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const std::vector<uint8_t>& mac_key_context,
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const std::vector<uint8_t>& enc_key_context);
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// Sign the buffer with server's mac key.
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void ServerSignBuffer(const uint8_t* data, size_t data_length,
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std::vector<uint8_t>* signature) const;
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// Sign the buffer with client's known mac key. Known test keys must be
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// installed first. This uses HMAC with SHA256, so is suitable for a message.
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void ClientSignBuffer(const std::vector<uint8_t>& buffer,
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std::vector<uint8_t>* signature) const;
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// Sign the pst buffer with client's known mac key. Known test keys must be
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// installed first. This uses HMAC with SHA128, and skips the beginning of the
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// buffer, so is only suitable for a pst report.
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void ClientSignPstReport(const std::vector<uint8_t>& pst_report_buffer,
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std::vector<uint8_t>* signature) const;
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void set_mac_keys(const uint8_t* mac_keys);
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private:
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// Internal utility function to derive key using CMAC-128
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void DeriveKey(const uint8_t* key, const std::vector<uint8_t>& context,
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int counter, std::vector<uint8_t>* out);
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std::vector<uint8_t> mac_key_server_;
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std::vector<uint8_t> mac_key_client_;
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};
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} // namespace wvoec
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#endif // CDM_OEC_KEY_DERIVER_H_
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