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/*
* TPM 1.2 interface
* (C) 2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_TPM_H__
#define BOTAN_TPM_H__
#include <botan/exceptn.h>
#include <botan/pk_keys.h>
#include <botan/bigint.h>
#include <botan/rng.h>
#include <botan/uuid.h>
//TODO remove this
#include <tss/tspi.h>
namespace Botan {
class TPM_Error : public Exception
{
public:
TPM_Error(const std::string& err) : Exception(err) {}
};
/**
* Creates a connection to the TPM. All other TPM types take and hold
* a TPM_Context reference, so all other objects must be deallocated
* before ~TPM_Context runs.
*
* Use nullptr for the srk_password to indicate the well known secret
* (ie, an unencrypted SRK). This is usually what you want.
*
* TODO: handling owner password?
*/
class BOTAN_DLL TPM_Context
{
public:
/**
* User callback for getting the PIN. Will be passed the best available
* description of what we are attempting to load.
*/
typedef std::function<std::string (std::string)> pin_cb;
TPM_Context(pin_cb cb, const char* srk_password);
~TPM_Context();
// Get data from the TPM's RNG, whatever that is
void gen_random(uint8_t out[], size_t out_len);
// Uses Tspi_TPM_StirRandom to add data to TPM's internal pool
void stir_random(const uint8_t in[], size_t in_len);
std::string get_user_pin(const std::string& who)
{
return m_pin_cb(who);
}
uint32_t current_counter();
TSS_HCONTEXT handle() const { return m_ctx; }
TSS_HKEY srk() const { return m_srk; }
private:
std::function<std::string (std::string)> m_pin_cb;
TSS_HCONTEXT m_ctx;
TSS_HKEY m_srk;
TSS_HTPM m_tpm;
};
class BOTAN_DLL TPM_RNG : public RandomNumberGenerator
{
public:
TPM_RNG(TPM_Context& ctx) : m_ctx(ctx) {}
void add_entropy(const byte in[], size_t in_len) override
{
m_ctx.stir_random(in, in_len);
}
void randomize(byte out[], size_t out_len) override
{
m_ctx.gen_random(out, out_len);
}
std::string name() const override { return "TPM_RNG"; }
bool is_seeded() const override { return true; }
void clear() const override {}
private:
TPM_Context& m_ctx;
};
enum class TPM_Storage_Type { User, System };
/*
* Also implements the public interface, but does not have usable
* TODO: derive from RSA_PublicKey???
*/
class BOTAN_DLL TPM_PrivateKey : public Private_Key
{
public:
// TODO: key import?
/*
* Create a new key on the TPM parented to the SRK
* @param bits must be 1024 or 2048
*/
TPM_PrivateKey(TPM_Context& ctx, size_t bits, const char* key_password);
// reference an existing TPM key using URL syntax from GnuTLS
// "tpmkey:uuid=79f07ca9-73ac-478a-9093-11ca6702e774;storage=user"
//TPM_PrivateKey(TPM_Context& ctx, const std::string& tpm_url);
TPM_PrivateKey(TPM_Context& ctx,
const std::string& uuid,
TPM_Storage_Type storage_type);
TPM_PrivateKey(TPM_Context& ctx,
const std::vector<uint8_t>& blob);
/**
* If the key is not currently registered under a known UUID,
* generates a new random UUID and registers the key.
* Returns the access URL.
*/
std::string register_key(TPM_Storage_Type storage_type);
/**
* Returns a copy of the public key
*/
std::unique_ptr<Public_Key> public_key() const;
std::vector<uint8_t> export_blob() const;
TPM_Context& ctx() const { return m_ctx; }
TSS_HKEY handle() const { return m_key; }
/*
* Returns the list of all keys (in URL format) registered with the system
*/
static std::vector<std::string> registered_keys(TPM_Context& ctx);
size_t estimated_strength() const override;
size_t max_input_bits() const override;
AlgorithmIdentifier algorithm_identifier() const override;
std::vector<byte> x509_subject_public_key() const override;
secure_vector<byte> pkcs8_private_key() const override;
bool check_key(RandomNumberGenerator& rng, bool) const override;
std::string algo_name() const override { return "RSA"; } // ???
private:
BigInt get_n() const;
BigInt get_e() const;
TPM_Context& m_ctx;
TSS_HKEY m_key;
// Only set for registered keys
UUID m_uuid;
TPM_Storage_Type m_storage;
// Lazily computed in get_n, get_e
mutable BigInt m_n, m_e;
};
// TODO: NVRAM interface
// TODO: PCR measurement, writing, key locking
}
#endif
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