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Emulator actual embodiment: SASP data persistent saving handling
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@divanchykhin
divanchykhin committed Jun 1, 2015
1 parent 359fcd4 commit 6cae114
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Showing 2 changed files with 46 additions and 15 deletions.
58 changes: 44 additions & 14 deletions tests/emulator/sasp_protocol.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,25 +28,47 @@ void SASP_initAtLifeStart( SASP_DATA* sasp_data )
sa_uint48_set_zero( sasp_data->nonce_ls );
sa_uint48_increment( sasp_data->nonce_ls );

eeprom_write( DATA_SASP_NONCE_LW_ID, sasp_data->nonce_lw, SASP_NONCE_TYPE_SIZE );
eeprom_write( DATA_SASP_NONCE_LS_ID, sasp_data->nonce_ls, SASP_NONCE_TYPE_SIZE );
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LW_ID, sasp_data->nonce_lw );
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LS_ID, sasp_data->nonce_ls );
}

void SASP_restoreFromBackup( SASP_DATA* sasp_data )
{
uint8_t size;

size = eeprom_read_size( DATA_SASP_NONCE_LW_ID );
assert( size == SASP_NONCE_TYPE_SIZE );
eeprom_read_fixed_size( DATA_SASP_NONCE_LW_ID, sasp_data->nonce_lw, size);
eeprom_read( EEPROM_SLOT_DATA_SASP_NONCE_LW_ID, sasp_data->nonce_lw, size);
eeprom_read( EEPROM_SLOT_DATA_SASP_NONCE_LS_ID, sasp_data->nonce_ls, size);
}

void SASP_increment_nonce_last_sent( SASP_DATA* sasp_data )
{
sa_uint48_increment( sasp_data->nonce_ls );
// TODO: make sure this is a reliable approach
if ( sa_uint48_get_byte( sasp_data->nonce_ls, 0 ) == 1 )
{
sasp_nonce_type future;
memcpy( future, sasp_data->nonce_ls, SASP_NONCE_TYPE_SIZE );
sa_uint48_roundup_to_the_nearest_multiple_of_0x100( future );
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LS_ID, future );
}
}

size = eeprom_read_size( DATA_SASP_NONCE_LS_ID );
assert( size == SASP_NONCE_TYPE_SIZE );
eeprom_read_fixed_size( DATA_SASP_NONCE_LS_ID, sasp_data->nonce_ls, size);
void SASP_update_nonce_low_watermark( SASP_DATA* sasp_data, const sasp_nonce_type new_val )
{
sasp_nonce_type future;
sa_uint48_init_by( future, sasp_data->nonce_lw );
sa_uint48_init_by( sasp_data->nonce_lw, new_val ); // update Nonce Low Watermark
sa_uint48_roundup_to_the_nearest_multiple_of_0x100( future ); // now 'future' has a value supposedly saved in eeprom
if ( sa_uint48_compare( new_val, future ) >= 0 )
{
sa_uint48_init_by( future, sasp_data->nonce_lw );
sa_uint48_roundup_to_the_nearest_multiple_of_0x100( future ); // now 'future' has a value supposedly saved in eeprom
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LW_ID, future );
}
}

INLINE
void sasp_make_nonce_for_encryption( const sasp_nonce_type packet_id, uint8_t master_slave_bit, uint8_t nonce[16] )
void SASP_make_nonce_for_encryption( const sasp_nonce_type packet_id, uint8_t master_slave_bit, uint8_t nonce[16] )
{
memset( nonce, 0, 16 );
int8_t i;
Expand All @@ -69,7 +91,7 @@ void SASP_EncryptAndAddAuthenticationData( REQUEST_REPLY_HANDLE mem_h, const uin
bool read_ok;

uint8_t nonce[16];
sasp_make_nonce_for_encryption( packet_id, MASTER_SLAVE_BIT, nonce );
SASP_make_nonce_for_encryption( packet_id, MASTER_SLAVE_BIT, nonce );

// intermediate buffers for EAX
uint8_t tag[SASP_TAG_SIZE];
Expand Down Expand Up @@ -135,7 +157,7 @@ bool SASP_IntraPacketAuthenticateAndDecrypt( const uint8_t* key, REQUEST_REPLY_H
zepto_parser_decode_encoded_uint_as_sa_uint48( &po, nonce_received );
sa_uint48_init_by( pid, nonce_received );
uint8_t nonce[ 16 ];
sasp_make_nonce_for_encryption( nonce_received, 1 - MASTER_SLAVE_BIT, nonce );
SASP_make_nonce_for_encryption( nonce_received, 1 - MASTER_SLAVE_BIT, nonce );

// read blocks one by one, authenticate, decrypt, write
bool read_ok;
Expand Down Expand Up @@ -312,7 +334,8 @@ uint8_t handler_sasp_receive( const uint8_t* key, uint8_t* pid, MEMORY_HANDLE me
{
INCREMENT_COUNTER( 14, "handler_sasp_receive(), nonce las updated" );
memcpy( nls, new_nls, SASP_NONCE_SIZE );
sa_uint48_increment( sasp_data->nonce_ls );
// sa_uint48_increment( sasp_data->nonce_ls );
SASP_increment_nonce_last_sent( sasp_data );
// TODO: shuold we do anything else?
return SASP_RET_TO_HIGHER_LAST_SEND_FAILED;
}
Expand Down Expand Up @@ -348,14 +371,21 @@ uint8_t handler_sasp_receive( const uint8_t* key, uint8_t* pid, MEMORY_HANDLE me
}

// 4. Finally, we have a brand new packet
sa_uint48_init_by( sasp_data->nonce_lw, pid ); // update Nonce Low Watermark
// sa_uint48_init_by( sasp_data->nonce_lw, pid ); // update Nonce Low Watermark
SASP_update_nonce_low_watermark( sasp_data, pid );
INCREMENT_COUNTER( 16, "handler_sasp_receive(), passed up" );
return SASP_RET_TO_HIGHER_NEW;
}

uint8_t handler_sasp_get_packet_id( sa_uint48_t buffOut, int buffOutSize, SASP_DATA* sasp_data )
{
sa_uint48_increment( sasp_data->nonce_ls );
SASP_increment_nonce_last_sent( sasp_data );
sa_uint48_init_by( buffOut, sasp_data->nonce_ls );
return SASP_RET_NONCE;
}

uint8_t handler_sasp_save_state( SASP_DATA* sasp_data )
{
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LW_ID, sasp_data->nonce_lw );
eeprom_write( EEPROM_SLOT_DATA_SASP_NONCE_LS_ID, sasp_data->nonce_ls );
}
3 changes: 2 additions & 1 deletion tests/emulator/sasp_protocol.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ Copyright (C) 2015 OLogN Technologies AG

#include "sa-common.h"
#include "sa-data-types.h"
#include "hal/sa-eeprom.h"
#include "sa-eeprom.h"
#include "zepto-mem-mngmt.h"

// RET codes
Expand Down Expand Up @@ -59,6 +59,7 @@ void SASP_restoreFromBackup( SASP_DATA* sasp_data );
uint8_t handler_sasp_receive( const uint8_t* key, uint8_t* packet_id, MEMORY_HANDLE mem_h, SASP_DATA* sasp_data );
uint8_t handler_sasp_send( const uint8_t* key, const uint8_t* packet_id, MEMORY_HANDLE mem_h, SASP_DATA* sasp_data );
uint8_t handler_sasp_get_packet_id( uint8_t* buffOut, int buffOutSize, SASP_DATA* sasp_data );
uint8_t handler_sasp_save_state( SASP_DATA* sasp_data );


#endif // __SASP_PROTOCOL_H__

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