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mbed-os/features/FEATURE_BLE/source/generic/GenericSecurityManager.cpp

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/* mbed Microcontroller Library
* Copyright (c) 2017-2018 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __GENERIC_SECURITY_MANAGER_H__
#define __GENERIC_SECURITY_MANAGER_H__
#include "SecurityManager.h"
#include "PalSecurityManager.h"
#include "Callback.h"
#include "ble/pal/GapTypes.h"
namespace ble {
namespace generic {
using ble::pal::address_t;
using ble::pal::advertising_peer_address_type_t;
using ble::pal::authentication_t;
using ble::pal::key_distribution_t;
using ble::pal::irk_t;
using ble::pal::csrk_t;
using ble::pal::ltk_t;
using ble::pal::ediv_t;
using ble::pal::rand_t;
using ble::pal::pairing_failure_t;
typedef SecurityManager::SecurityIOCapabilities_t SecurityIOCapabilities_t;
class PasskeyNum {
public:
PasskeyNum() : number(0) { }
PasskeyNum(uint32_t num) : number(num) { }
operator uint32_t() {
return number;
}
uint32_t number;
};
class PasskeyAsci {
public:
static const uint8_t NUMBER_OFFSET = '0';
PasskeyAsci(const uint8_t* passkey) {
if (passkey) {
memcpy(asci, passkey, SecurityManager::PASSKEY_LEN);
} else {
memset(asci, NUMBER_OFFSET, SecurityManager::PASSKEY_LEN);
}
}
PasskeyAsci() {
memset(asci, NUMBER_OFFSET, SecurityManager::PASSKEY_LEN);
}
PasskeyAsci(const PasskeyNum& passkey) {
for (size_t i = 5, m = 100000; i >= 0; --i, m /= 10) {
uint32_t result = passkey.number / m;
asci[i] = NUMBER_OFFSET + result;
passkey.number -= result;
}
}
operator PasskeyNum() {
return PasskeyNum(to_num(asci));
}
static uint32_t to_num(const uint8_t* asci) {
uint32_t passkey = 0;
for (size_t i = 0, m = 1; i < SecurityManager::PASSKEY_LEN; ++i, m *= 10) {
passkey += (asci[i] - NUMBER_OFFSET) * m;
}
return passkey;
}
uint8_t asci[SecurityManager::PASSKEY_LEN];
};
/* separate structs to allow db implementation to minimise memory usage */
struct SecurityEntry_t {
connection_handle_t handle;
address_t peer_identity_address;
uint8_t encryption_key_size;
uint8_t peer_address_public:1;
uint8_t mitm_protection:1; /**< does the key provide mitm */
uint8_t keypress_notification:1;
uint8_t connected:1;
uint8_t authenticated:1; /**< have we authenticated during this connection */
uint8_t sign_data:1;
uint8_t encrypt_data:1;
uint8_t oob_mitm_protection:1;
uint8_t oob:1;
uint8_t secure_connections:1;
};
struct SecurityEntryKeys_t {
ltk_t ltk;
ediv_t ediv;
rand_t rand;
};
struct SecurityEntryIdentity_t {
irk_t irk;
csrk_t csrk;
};
enum DbCbAction_t {
DB_CB_ACTION_UPDATE,
DB_CB_ACTION_NO_UPDATE_REQUIRED, /* does not guarantee discarding changes if you made any */
DB_CB_ACTION_REMOVE
};
typedef mbed::Callback<DbCbAction_t(SecurityEntry_t&)> SecurityEntryDbCb_t;
typedef mbed::Callback<DbCbAction_t(SecurityEntry_t&, SecurityEntryKeys_t&)> SecurityEntryKeysDbCb_t;
typedef mbed::Callback<DbCbAction_t(SecurityEntry_t&, SecurityEntryIdentity_t&)> SecurityEntryIdentityDbCb_t;
typedef mbed::Callback<DbCbAction_t(Gap::Whitelist_t&)> WhitelistDbCb_t;
class GenericSecurityManagerEventHandler;
/**
* SecurityDB holds the state for active connections and bonded devices.
* Keys can be stored in NVM and are returned via callbacks.
* SecurityDB is responsible for serialising any requests and keeping
* the store in a consistent state.
* Active connections state must be returned immediately.
*/
class SecurityDb {
public:
SecurityDb() {};
~SecurityDb() {};
/**
* Return immediately security entry containing the state
* information for active connection.
* @param[in] handle valid connection handle
* @return pointer to security entry, NULL if handle was invalid
*/
SecurityEntry_t* get_entry(connection_handle_t connection);
void get_entry_keys(SecurityEntryKeysDbCb_t cb, ediv_t ediv, rand_t rand);
void get_entry_identityt(SecurityEntryIdentityDbCb_t cb, address_t identity_address);
void update_entry(connection_handle_t connection,
bool address_is_public,
address_t &peer_address,
ediv_t &ediv,
rand_t &rand,
ltk_t &ltk,
irk_t &irk,
csrk_t &csrk);
void update_entry_ltk(connection_handle_t connection,
ltk_t &ltk);
void update_entry_ediv_rand(connection_handle_t connection,
ediv_t &ediv,
rand_t &rand);
void update_entry_irk(connection_handle_t connection,
irk_t &irk);
void update_entry_bdaddr(connection_handle_t connection,
bool address_is_public,
address_t &peer_address);
void update_entry_csrk(connection_handle_t connection,
csrk_t &csrk);
void remove_entry(SecurityEntry_t&);
void clear_entries();
void get_whitelist(WhitelistDbCb_t cb);
void update_whitelist(Gap::Whitelist_t&);
void add_whitelist_entry(address_t);
void remove_whitelist_entry(address_t);
void clear_whitelist();
void restore();
void sync();
void setRestore(bool reload);
private:
};
class GenericSecurityManager : public SecurityManager,
public ble::pal::SecurityManagerEventHandler {
public:
////////////////////////////////////////////////////////////////////////////
// SM lifecycle management
//
ble_error_t init(bool initBondable = true,
bool initMITM = true,
SecurityIOCapabilities_t initIocaps = IO_CAPS_NONE,
const Passkey_t initPasskey = NULL) {
db.restore();
bondable = initBondable;
mitm = initMITM;
io_capability = initIocaps;
displayPasskey = PasskeyAsci(initPasskey);
legacyPairingAllowed = true;
return BLE_ERROR_NONE;
}
ble_error_t reset(void) {
db.sync();
SecurityManager::reset();
return BLE_ERROR_NONE;
}
ble_error_t preserveBondingStateOnReset(bool enabled) {
db.setRestore(enabled);
return BLE_ERROR_NONE;
}
////////////////////////////////////////////////////////////////////////////
// List management
//
ble_error_t purgeAllBondingState(void) {
db.clear_entries();
return BLE_ERROR_NONE;
}
////////////////////////////////////////////////////////////////////////////
// Feature support
//
ble_error_t allowLegacyPairing(bool allow = true) {
legacyPairingAllowed = allow;
return BLE_ERROR_NONE;
}
ble_error_t getSecureConnectionsSupport(bool *enabled) {
return pal.get_secure_connections_support(*enabled);
}
////////////////////////////////////////////////////////////////////////////
// Security settings
//
virtual ble_error_t setDisplayPasskey(const Passkey_t passkey) {
displayPasskey = passkey;
return BLE_ERROR_NONE;
}
ble_error_t setAuthenticationTimeout(connection_handle_t connection,
uint32_t timeout_in_ms) {
return pal.set_authentication_timeout(connection, timeout_in_ms / 10);
}
ble_error_t getAuthenticationTimeout(connection_handle_t connection,
uint32_t *timeout_in_ms) {
uint16_t timeout_in_10ms;
ble_error_t status = pal.get_authentication_timeout(connection, timeout_in_10ms);
*timeout_in_ms = 10 * timeout_in_10ms;
return status;
}
ble_error_t setLinkSecurity(connection_handle_t connection,
SecurityMode_t securityMode) {
return BLE_ERROR_NOT_IMPLEMENTED;
}
ble_error_t getLinkSecurity(connection_handle_t connection,
SecurityMode_t *securityMode) {
securityMode = SECURITY_MODE_ENCRYPTION_OPEN_LINK;
return BLE_ERROR_NONE;
}
ble_error_t setKeypressNotification(bool enabled = true) {
keypressNotification = enabled;
return BLE_ERROR_NONE;
}
////////////////////////////////////////////////////////////////////////////
// Encryption
//
/**
* @deprecated
*
* Get the security status of a connection.
*
* @param[in] connection Handle to identify the connection.
* @param[out] securityStatusP Security status.
*
* @return BLE_ERROR_NONE or appropriate error code indicating the failure reason.
*/
ble_error_t getLinkSecurity(connection_handle_t connection, LinkSecurityStatus_t *securityStatusP) {
return pal.get_encryption_status(connection, *securityStatusP);
}
ble_error_t getEncryptionKeySize(connection_handle_t connection, uint8_t *size) {
SecurityEntry_t *entry = db.get_entry(connection);
if (entry) {
*size = entry->encryption_key_size;
return BLE_ERROR_NONE;
} else {
return BLE_ERROR_INVALID_PARAM;
}
}
////////////////////////////////////////////////////////////////////////////
// Privacy
//
virtual ble_error_t setPrivateAddressTimeout(uint16_t timeout_in_seconds) {
return pal.set_private_address_timeout(timeout_in_seconds);
}
////////////////////////////////////////////////////////////////////////////
// Keys
//
/**
* Returns the requested LTK to the PAL. Called by the security db.
*
* @param entry security entry returned by the database.
* @param entryKeys security entry containing keys.
*
* @return no action instruction to the db since this only reads the keys.
*/
DbCbAction_t setLtkCb(SecurityEntry_t& entry, SecurityEntryKeys_t& entryKeys) {
pal.set_ltk(entry.handle, entryKeys.ltk);
return DB_CB_ACTION_NO_UPDATE_REQUIRED;
}
////////////////////////////////////////////////////////////////////////////
// Authentication
//
ble_error_t requestPairing(connection_handle_t connection) {
(void) connection;
return BLE_ERROR_NOT_IMPLEMENTED; /* Requesting action from porters: override this API if security is supported. */
}
ble_error_t acceptPairingRequest(connection_handle_t connection) {
(void) connection;
return BLE_ERROR_NOT_IMPLEMENTED; /* Requesting action from porters: override this API if security is supported. */
}
ble_error_t canceltPairingRequest(connection_handle_t connection) {
return pal.cancel_pairing(connection, pairing_failure_t::UNSPECIFIED_REASON);
}
ble_error_t requestAuthentication(connection_handle_t connection) {
(void) connection;
return BLE_ERROR_NOT_IMPLEMENTED; /* Requesting action from porters: override this API if security is supported. */
}
ble_error_t setPairingRequestAuthorisation(bool required = true) {
authorisationRequired = required;
return BLE_ERROR_NONE;
}
////////////////////////////////////////////////////////////////////////////
// MITM
//
ble_error_t setOOBDataUsage(connection_handle_t connection,
bool useOOB, bool OOBProvidesMITM = true) {
SecurityEntry_t *entry = db.get_entry(connection);
if (entry) {
entry->oob = useOOB;
entry->oob_mitm_protection = OOBProvidesMITM;
return BLE_ERROR_NONE;
} else {
return BLE_ERROR_INVALID_PARAM;
}
}
virtual ble_error_t confirmationEntered(connection_handle_t connection,
bool confirmation) {
return pal.confirmation_entered(connection, confirmation);
}
virtual ble_error_t passkeyEntered(connection_handle_t connection,
Passkey_t passkey) {
return pal.passkey_request_reply(
connection,
PasskeyAsci::to_num(passkey)
);
}
virtual ble_error_t sendKeypressNotification(connection_handle_t connection,
Keypress_t keypress) {
return pal.send_keypress_notification(connection, keypress);
}
////////////////////////////////////////////////////////////////////////////
// Event handler
//
void setSecurityManagerEventHandler(::SecurityManager::SecurityManagerEventHandler* handler) {
SecurityManager::setSecurityManagerEventHandler(handler);
if (handler) {
_app_event_handler = handler;
}
}
protected:
GenericSecurityManager(ble::pal::SecurityManager& palImpl) : pal(palImpl) {
_app_event_handler = &defaultEventHandler;
pal.set_event_handler(this);
}
private:
ble::pal::SecurityManager& pal;
SecurityDb db;
SecurityIOCapabilities_t io_capability;
PasskeyNum displayPasskey;
bool mitm;
bool bondable;
bool authorisationRequired;
bool keypressNotification;
bool oobProvidesMitmProtection;
bool legacyPairingAllowed;
authentication_t authentication;
uint8_t minKeySize;
uint8_t maxKeySize;
key_distribution_t initiatorDist;
key_distribution_t responderDist;
/* implements ble::pal::SecurityManagerEventHandler */
public:
void on_security_setup_initiated(connection_handle_t connection,
bool allow_bonding,
bool require_mitm,
SecurityIOCapabilities_t iocaps) {
if (_app_event_handler) {
_app_event_handler->securitySetupInitiated(connection, allow_bonding, require_mitm, iocaps);
}
}
void on_security_setup_completed(connection_handle_t connection,
SecurityManager::SecurityCompletionStatus_t status) {
if (_app_event_handler) {
_app_event_handler->securitySetupCompleted(connection, status);
}
}
void on_link_secured(connection_handle_t connection,
SecurityManager::SecurityMode_t security_mode) {
if (_app_event_handler) {
_app_event_handler->linkSecured(connection, security_mode);
}
}
void on_security_context_stored(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->securityContextStored(connection);
}
}
void on_passkey_display(connection_handle_t connection,
const SecurityManager::Passkey_t passkey) {
if (_app_event_handler) {
_app_event_handler->passkeyDisplay(connection, passkey);
}
}
void on_valid_mic_timeout(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->validMicTimeout(connection);
}
}
void on_link_key_failure(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->linkKeyFailure(connection);
}
}
void on_keypress_notification(connection_handle_t connection,
SecurityManager::Keypress_t keypress) {
if (_app_event_handler) {
_app_event_handler->keypressNotification(connection, keypress);
}
}
void on_legacy_pariring_oob_request(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->legacyPairingOobRequest(connection);
}
}
void on_oob_request(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->oobRequest(connection);
}
}
void on_pin_request(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->pinRequest(connection);
}
}
void on_passkey_request(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->passkeyRequest(connection);
}
}
void on_confirmation_request(connection_handle_t connection) {
if (_app_event_handler) {
_app_event_handler->confirmationRequest(connection);
}
}
void on_accept_pairing_request(connection_handle_t connection,
SecurityIOCapabilities_t iocaps,
bool use_oob,
authentication_t authentication,
uint8_t max_key_size,
key_distribution_t initiator_dist,
key_distribution_t responder_dist) {
if (_app_event_handler && authorisationRequired) {
_app_event_handler->acceptPairingRequest(connection);
}
}
void on_keys_distributed(connection_handle_t connection,
advertising_peer_address_type_t peer_address_type,
address_t &peer_identity_address,
ediv_t &ediv,
rand_t &rand,
ltk_t &ltk,
irk_t &irk,
csrk_t &csrk) {
db.update_entry(
connection,
(peer_address_type == advertising_peer_address_type_t::PUBLIC_ADDRESS),
peer_identity_address,
ediv,
rand,
ltk,
irk,
csrk
);
}
void on_keys_distributed_ltk(connection_handle_t connection,
ltk_t &ltk) {
db.update_entry_ltk(connection, ltk);
}
void on_keys_distributed_ediv_rand(connection_handle_t connection,
ediv_t &ediv,
rand_t &rand) {
db.update_entry_ediv_rand(connection, ediv, rand);
}
void on_keys_distributed_irk(connection_handle_t connection,
irk_t &irk) {
db.update_entry_irk(connection, irk);
}
void on_keys_distributed_bdaddr(connection_handle_t connection,
advertising_peer_address_type_t peer_address_type,
address_t &peer_identity_address) {
db.update_entry_bdaddr(
connection,
(peer_address_type == advertising_peer_address_type_t::PUBLIC_ADDRESS),
peer_identity_address
);
}
void on_keys_distributed_csrk(connection_handle_t connection,
csrk_t &csrk) {
db.update_entry_csrk(connection, csrk);
}
void on_ltk_request(connection_handle_t connection,
ediv_t &ediv,
rand_t &rand) {
db.get_entry_keys(mbed::callback(this, &GenericSecurityManager::setLtkCb), ediv, rand);
}
private:
/* handler is always a valid pointer */
::SecurityManager::SecurityManagerEventHandler *_app_event_handler;
};
} /* namespace generic */
} /* namespace ble */
#endif /*__GENERIC_SECURITY_MANAGER_H__*/
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