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Merge remote-tracking branch 'public/pr/2986' into baremetal

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Simon Butcher 2020-01-30 19:49:37 +00:00
parent 28ecfb002f 17540ab74c
commit 8eefb9b3b8
2 changed files with 359 additions and 158 deletions
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9
include/mbedtls/config.h
View file

@ -640,10 +640,13 @@
* Add countermeasures against possible side-channel-attack to AES calculation.
*
* Uncommenting this macro adds additional calculation rounds to AES
* calculation. Additional rounds are using random data and can occur in any
* AES calculation round.
* calculation. Additional rounds are using random data for calculation. The
* additional rounds are added to:
* -initial key addition phase
* -before the first AES calculation round
* -after the last AES calculation round
*
* Tradeoff: Uncommenting this increases ROM footprint by ~100 bytes.
* Tradeoff: Uncommenting this macro does not increase codesize.
* The performance loss is ~50% with 128 bit AES.
*
* This option is dependent of \c MBEDTLS_ENTROPY_HARDWARE_ALT.

508
library/aes.c
View file

@ -94,10 +94,8 @@ typedef struct {
} aes_r_data_t;
#if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
/* Number of additional AES calculation rounds added for SCA CM */
#define AES_SCA_CM_ROUNDS 3
#else /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#define AES_SCA_CM_ROUNDS 0
/* Number of additional AES dummy rounds added for SCA countermeasures */
#define AES_SCA_CM_ROUNDS 5
#endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#if defined(MBEDTLS_PADLOCK_C) && \
@ -513,99 +511,105 @@ static void aes_gen_tables( void )
#endif /* MBEDTLS_AES_ROM_TABLES */
/**
* Randomize positions when to use AES SCA countermeasures.
* Each byte indicates one AES round as follows:
* first ( tbl_len - 4 ) bytes are reserved for middle AES rounds:
* -4 high bit = table to use 0x10 for SCA CM data, 0 otherwise
* -4 low bits = offset based on order, 4 for even position, 0 otherwise
* Last 4 bytes for first(2) and final(2) round calculation
* -4 high bit = table to use, 0x10 for SCA CM data, otherwise real data
* -4 low bits = not used
* Randomize positions for AES SCA countermeasures if AES countermeasures are
* enabled. If the countermeasures are not enabled then we fill the given table
* with only real AES rounds to be executed.
*
* Dummy rounds are added as follows:
* 1. One dummy round added to the initial round key addition (executed in
* random order).
* 2. Random number of dummy rounds added as first and/or last AES calculation
* round. Total number of dummy rounds is AES_SCA_CM_ROUNDS.
*
* Description of the bytes in the table are as follows:
* - 2 bytes for initial round key addition
* - remaining bytes for AES calculation with real or dummy data
*
* Each byte indicates one AES calculation round:
* -4 high bit = table to use 0x10 for dummy data, 0x00 real data
* -bit 2 = offset for even/odd rounds
* -bit 0-1: stop mark (0x03) to indicate calculation end
*
* Return Number of additional AES rounds
*
* Example of the control bytes:
* Control data when only real data (R) is used:
* | R | R | R | R | R | R | R | R | Start | Final |
* |0x04|0x00|0x00|0x04|0x00|0x04|0x00|0x04|0x00|0x00|0x00|0x00|
* R = real data in actual AES calculation round
* Ri = Real data in initial round key addition phase
* F = fake data in actual AES calculation round
* Fi = fake data in initial round key addition phase
*
* Control data with 5 (F) dummy rounds and randomized start and final round:
* | R | F | R | F | F | R | R | R | R | R | R | START RF| FINAL FR|
* |0x04|0x10|0x04|0x10|0x10|0x00|0x04|0x00|0x04|0x00|0x04|0x00|0x10|0x10|0x00|
* 1. No countermeasures enabled and AES-128, only real data (R) used:
* | Ri | R | R | R | R | R | R | R | R | R | R |
* |0x03|0x04|0x00|0x04|0x00|0x04|0x00|0x04|0x00|0x07|0x03|
*
* 2. Countermeasures enabled, 3 (F) dummy rounds in start and 1 at end:
* | Fi | Ri | F | F | F | R | R | ... | R | R | R | R | F |
* |0x10|0x03|0x10|0x10|0x10|0x04|0x00| ... |0x04|0x00|0x04|0x03|0x07|
*/
#if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
static int aes_sca_cm_data_randomize( uint8_t *tbl, uint8_t tbl_len )
{
int i, is_even_pos;
#if AES_SCA_CM_ROUNDS != 0
int is_unique_number;
int num;
#endif
int i = 0, j, is_even_pos, dummy_rounds, num;
mbedtls_platform_memset( tbl, 0, tbl_len );
// get random from 0x0fff (each f will be used separately)
num = mbedtls_platform_random_in_range( 0x1000 );
#if AES_SCA_CM_ROUNDS != 0
// Randomize SCA CM positions to tbl
for( i = 0; i < AES_SCA_CM_ROUNDS; i++ )
// Randomize execution order of initial round key addition
if ( ( num & 0x0100 ) == 0 )
{
is_unique_number = 0;
do
{
is_unique_number++;
num = mbedtls_platform_random_in_range( tbl_len - 4 );
if( is_unique_number > 10 )
{
// prevent forever loop if random returns constant
is_unique_number = 0;
tbl[i] = 0x10; // fake data
}
if( tbl[num] == 0 )
{
is_unique_number = 0;
tbl[num] = 0x10; // fake data
}
} while( is_unique_number != 0 );
tbl[i++] = 0x10; // dummy data
tbl[i++] = 0x00 | 0x03; // real data + stop marker
} else {
tbl[i++] = 0x00; // real data
tbl[i++] = 0x10 | 0x03; // dummy data + stop marker
}
// randomize control data for start and final round
for( i = 1; i <= 2; i++ )
{
num = mbedtls_platform_random_in_range( 0xff );
if( ( num % 2 ) == 0 )
{
tbl[tbl_len - ( i * 2 - 0 )] = 0x10; // fake data
tbl[tbl_len - ( i * 2 - 1 )] = 0x00; // real data
}
else
{
tbl[tbl_len - ( i * 2 - 0 )] = 0x00; // real data
tbl[tbl_len - ( i * 2 - 1 )] = 0x10; // fake data
}
}
#endif /* AES_SCA_CM_ROUNDS != 0 */
// Randomize number of dummy AES rounds
dummy_rounds = AES_SCA_CM_ROUNDS - ( ( num & 0x0010 ) >> 4 );
tbl_len = tbl_len - (AES_SCA_CM_ROUNDS - dummy_rounds);
// Fill real AES round data to the remaining places
// randomize positions for the dummy rounds
num = ( num & 0x000f ) % ( dummy_rounds + 1 );
// add dummy rounds after initial round key addition (if needed)
for ( ; i < num + 2; i++ )
{
tbl[i] = 0x10; // dummy data
}
// add dummy rounds to the end, (AES_SCA_CM_ROUNDS - num) rounds if needed
for ( j = tbl_len - dummy_rounds + num; j < tbl_len; j++ )
{
tbl[j] = 0x10; // dummy data
}
// Fill real AES data to the remaining places
is_even_pos = 1;
for( i = 0; i < tbl_len - 4; i++ )
for( ; i < tbl_len; i++ )
{
if( tbl[i] == 0 )
{
if( is_even_pos == 1 )
{
tbl[i] = 0x04; // real data, offset 4
tbl[i] = 0x04; // real data, offset for rounds 1,3,5, etc...
is_even_pos = 0;
}
else
{
tbl[i] = 0x00; // real data, offset 0
tbl[i] = 0x00; // real data, offset for rounds 2,4,6,...
is_even_pos = 1;
}
j = i; // remember the final round position in table
}
}
return( AES_SCA_CM_ROUNDS );
tbl[( tbl_len - 1)] |= 0x03; // Stop marker for the last item in tbl
tbl[( j - 1 )] |= 0x03; // stop marker for final - 1 real data
return( dummy_rounds );
}
#endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#if defined(MBEDTLS_AES_FEWER_TABLES)
@ -995,6 +999,7 @@ int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx,
*/
#if !defined(MBEDTLS_AES_ENCRYPT_ALT)
#if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
static uint32_t *aes_fround( uint32_t *R,
uint32_t *X0, uint32_t *X1, uint32_t *X2, uint32_t *X3,
uint32_t Y0, uint32_t Y1, uint32_t Y2, uint32_t Y3 )
@ -1051,62 +1056,65 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int i, j, offset, start_fin_loops = 1;
int i, tindex, offset, stop_mark, dummy_rounds;
aes_r_data_t aes_data_real; // real data
#if AES_SCA_CM_ROUNDS != 0
aes_r_data_t aes_data_fake; // fake data
#endif /* AES_SCA_CM_ROUNDS != 0 */
aes_r_data_t *aes_data_ptr; // pointer to aes_data_real or aes_data_fake
aes_r_data_t *aes_data_ptr; // pointer to real or fake data
aes_r_data_t *aes_data_table[2]; // pointers to real and fake data
int round_ctrl_table_len = ctx->nr - 1 + AES_SCA_CM_ROUNDS + 2 + 2;
int round_ctrl_table_len = ctx->nr + 2 + AES_SCA_CM_ROUNDS;
volatile int flow_control;
// control bytes for AES rounds, reserve based on max ctx->nr
uint8_t round_ctrl_table[ 14 - 1 + AES_SCA_CM_ROUNDS + 2 + 2];
// control bytes for AES calculation rounds,
// reserve based on max rounds + dummy rounds + 2 (for initial key addition)
uint8_t round_ctrl_table[( 14 + AES_SCA_CM_ROUNDS + 2 )];
aes_data_real.rk_ptr = ctx->rk;
aes_data_table[0] = &aes_data_real;
#if AES_SCA_CM_ROUNDS != 0
aes_data_table[1] = &aes_data_fake;
aes_data_fake.rk_ptr = ctx->rk;
start_fin_loops = 2;
for( i = 0; i < 4; i++ )
aes_data_fake.xy_values[i] = mbedtls_platform_random_in_range( 0xffffffff );
#endif
aes_data_table[0] = &aes_data_real;
aes_data_table[1] = &aes_data_fake;
// Get randomized AES calculation control bytes
flow_control = aes_sca_cm_data_randomize( round_ctrl_table,
round_ctrl_table_len );
// Get AES calculation control bytes
dummy_rounds = aes_sca_cm_data_randomize( round_ctrl_table,
round_ctrl_table_len );
flow_control = dummy_rounds;
// SCA countermeasure, safely clear the aes_data_real.xy_values
mbedtls_platform_memset( aes_data_real.xy_values, 0, 16 );
// SCA countermeasure, randomize secret data location by initializing it in
// a random order and writing randomized fake data between the real data
// writes.
offset = mbedtls_platform_random_in_range( 4 );
for( i = offset; i < 4; i++ )
i = offset;
do
{
GET_UINT32_LE( aes_data_real.xy_values[i], input, ( i * 4 ) );
}
aes_data_fake.xy_values[i] = mbedtls_platform_random_in_range( 0xffffffff );
flow_control++;
} while( ( i = ( i + 1 ) % 4 ) != offset );
for( i = 0; i < offset; i++ )
tindex = 0;
do
{
GET_UINT32_LE( aes_data_real.xy_values[i], input, ( i * 4 ) );
}
// Get pointer to the real or fake data
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
stop_mark = round_ctrl_table[tindex] & 0x03;
for( i = 0; i < 4; i++ )
{
for( j = 0; j < start_fin_loops; j++ )
// initial round key addition
for( i = 0; i < 4; i++ )
{
aes_data_ptr =
aes_data_table[round_ctrl_table[ round_ctrl_table_len - 2 + j ] >> 4];
aes_data_ptr->xy_values[i] ^= *aes_data_ptr->rk_ptr++;
flow_control++;
}
}
tindex++;
flow_control++;
} while( stop_mark == 0 );
for( i = 0; i < ( ctx->nr - 1 + AES_SCA_CM_ROUNDS ); i++ )
// Calculate AES rounds (9, 11 or 13 rounds) + dummy rounds
do
{
// Read AES control data
aes_data_ptr = aes_data_table[round_ctrl_table[i] >> 4];
offset = round_ctrl_table[i] & 0x0f;
// Get pointer to the real or fake data
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
offset = round_ctrl_table[tindex] & 0x04;
stop_mark = round_ctrl_table[tindex] & 0x03;
aes_data_ptr->rk_ptr = aes_fround( aes_data_ptr->rk_ptr,
&aes_data_ptr->xy_values[0 + offset],
@ -1117,12 +1125,15 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
aes_data_ptr->xy_values[5 - offset],
aes_data_ptr->xy_values[6 - offset],
aes_data_ptr->xy_values[7 - offset] );
tindex++;
flow_control++;
}
} while( stop_mark == 0 );
for( j = 0; j < start_fin_loops; j++ )
// Calculate final AES round + dummy rounds
do
{
aes_data_ptr = aes_data_table[round_ctrl_table[ i + j ] >> 4];
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
stop_mark = round_ctrl_table[tindex] & 0x03;
aes_fround_final( aes_data_ptr->rk_ptr,
&aes_data_ptr->xy_values[0],
&aes_data_ptr->xy_values[1],
@ -1133,25 +1144,23 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
aes_data_ptr->xy_values[6],
aes_data_ptr->xy_values[7] );
flow_control++;
}
tindex++;
} while( stop_mark == 0 );
// SCA countermeasure, safely clear the output
mbedtls_platform_memset( output, 0, 16 );
// SCA countermeasure, randomize secret data location by writing to it in
// a random order.
offset = mbedtls_platform_random_in_range( 4 );
for( i = offset; i < 4; i++ )
i = offset;
do
{
PUT_UINT32_LE( aes_data_real.xy_values[i], output, ( i * 4 ) );
flow_control++;
}
} while( ( i = ( i + 1 ) % 4 ) != offset );
for( i = 0; i < offset; i++ )
{
PUT_UINT32_LE( aes_data_real.xy_values[i], output, ( i * 4 ) );
flow_control++;
}
if( flow_control == ( AES_SCA_CM_ROUNDS + ( 4 * start_fin_loops ) +
ctx->nr - 1 + AES_SCA_CM_ROUNDS + start_fin_loops + 4 ) )
if( flow_control == tindex + dummy_rounds + 8 )
{
/* Validate control path due possible fault injection */
return 0;
@ -1159,6 +1168,87 @@ int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#else /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#define AES_FROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \
do \
{ \
(X0) = *RK++ ^ AES_FT0( ( (Y0) ) & 0xFF ) ^ \
AES_FT1( ( (Y1) >> 8 ) & 0xFF ) ^ \
AES_FT2( ( (Y2) >> 16 ) & 0xFF ) ^ \
AES_FT3( ( (Y3) >> 24 ) & 0xFF ); \
\
(X1) = *RK++ ^ AES_FT0( ( (Y1) ) & 0xFF ) ^ \
AES_FT1( ( (Y2) >> 8 ) & 0xFF ) ^ \
AES_FT2( ( (Y3) >> 16 ) & 0xFF ) ^ \
AES_FT3( ( (Y0) >> 24 ) & 0xFF ); \
\
(X2) = *RK++ ^ AES_FT0( ( (Y2) ) & 0xFF ) ^ \
AES_FT1( ( (Y3) >> 8 ) & 0xFF ) ^ \
AES_FT2( ( (Y0) >> 16 ) & 0xFF ) ^ \
AES_FT3( ( (Y1) >> 24 ) & 0xFF ); \
\
(X3) = *RK++ ^ AES_FT0( ( (Y3) ) & 0xFF ) ^ \
AES_FT1( ( (Y0) >> 8 ) & 0xFF ) ^ \
AES_FT2( ( (Y1) >> 16 ) & 0xFF ) ^ \
AES_FT3( ( (Y2) >> 24 ) & 0xFF ); \
} while( 0 )
int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int i;
uint32_t *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;
RK = ctx->rk;
GET_UINT32_LE( X0, input, 0 ); X0 ^= *RK++;
GET_UINT32_LE( X1, input, 4 ); X1 ^= *RK++;
GET_UINT32_LE( X2, input, 8 ); X2 ^= *RK++;
GET_UINT32_LE( X3, input, 12 ); X3 ^= *RK++;
for( i = ( ctx->nr >> 1 ) - 1; i > 0; i-- )
{
AES_FROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
AES_FROUND( X0, X1, X2, X3, Y0, Y1, Y2, Y3 );
}
AES_FROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
X0 = *RK++ ^ \
( (uint32_t) FSb[ ( Y0 ) & 0xFF ] ) ^
( (uint32_t) FSb[ ( Y1 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) FSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) FSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );
X1 = *RK++ ^ \
( (uint32_t) FSb[ ( Y1 ) & 0xFF ] ) ^
( (uint32_t) FSb[ ( Y2 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) FSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) FSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );
X2 = *RK++ ^ \
( (uint32_t) FSb[ ( Y2 ) & 0xFF ] ) ^
( (uint32_t) FSb[ ( Y3 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) FSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) FSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );
X3 = *RK++ ^ \
( (uint32_t) FSb[ ( Y3 ) & 0xFF ] ) ^
( (uint32_t) FSb[ ( Y0 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) FSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) FSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );
PUT_UINT32_LE( X0, output, 0 );
PUT_UINT32_LE( X1, output, 4 );
PUT_UINT32_LE( X2, output, 8 );
PUT_UINT32_LE( X3, output, 12 );
return( 0 );
}
#endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#endif /* !MBEDTLS_AES_ENCRYPT_ALT */
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
@ -1177,6 +1267,7 @@ void mbedtls_aes_encrypt( mbedtls_aes_context *ctx,
#if !defined(MBEDTLS_AES_DECRYPT_ALT)
#if !defined(MBEDTLS_AES_ONLY_ENCRYPT)
#if defined(MBEDTLS_AES_SCA_COUNTERMEASURES)
static uint32_t *aes_rround( uint32_t *R,
uint32_t *X0, uint32_t *X1, uint32_t *X2, uint32_t *X3,
uint32_t Y0, uint32_t Y1, uint32_t Y2, uint32_t Y3 )
@ -1232,50 +1323,65 @@ int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int i, j, offset, start_fin_loops = 1;
int i, tindex, offset, stop_mark, dummy_rounds;
aes_r_data_t aes_data_real; // real data
#if AES_SCA_CM_ROUNDS != 0
aes_r_data_t aes_data_fake; // fake data
#endif /* AES_SCA_CM_ROUNDS != 0 */
aes_r_data_t *aes_data_ptr; // pointer to aes_data_real or aes_data_fake
aes_r_data_t *aes_data_ptr; // pointer to real or fake data
aes_r_data_t *aes_data_table[2]; // pointers to real and fake data
int round_ctrl_table_len = ctx->nr - 1 + AES_SCA_CM_ROUNDS + 2 + 2;
// control bytes for AES rounds, reserve based on max ctx->nr
int round_ctrl_table_len = ctx->nr + 2 + AES_SCA_CM_ROUNDS;
volatile int flow_control;
uint8_t round_ctrl_table[ 14 - 1 + AES_SCA_CM_ROUNDS + 2 + 2 ];
// control bytes for AES calculation rounds,
// reserve based on max rounds + dummy rounds + 2 (for initial key addition)
uint8_t round_ctrl_table[( 14 + AES_SCA_CM_ROUNDS + 2 )];
aes_data_real.rk_ptr = ctx->rk;
aes_data_table[0] = &aes_data_real;
#if AES_SCA_CM_ROUNDS != 0
aes_data_table[1] = &aes_data_fake;
aes_data_fake.rk_ptr = ctx->rk;
start_fin_loops = 2;
for( i = 0; i < 4; i++ )
aes_data_fake.xy_values[i] = mbedtls_platform_random_in_range( 0xffffffff );
#endif
aes_data_table[0] = &aes_data_real;
aes_data_table[1] = &aes_data_fake;
// Get randomized AES calculation control bytes
flow_control = aes_sca_cm_data_randomize( round_ctrl_table,
round_ctrl_table_len );
// Get AES calculation control bytes
dummy_rounds = aes_sca_cm_data_randomize( round_ctrl_table,
round_ctrl_table_len );
flow_control = dummy_rounds;
for( i = 0; i < 4; i++ )
// SCA countermeasure, safely clear the aes_data_real.xy_values
mbedtls_platform_memset( aes_data_real.xy_values, 0, 16 );
// SCA countermeasure, randomize secret data location by initializing it in
// a random order and writing randomized fake data between the real data
// writes.
offset = mbedtls_platform_random_in_range( 4 );
i = offset;
do
{
GET_UINT32_LE( aes_data_real.xy_values[i], input, ( i * 4 ) );
for( j = 0; j < start_fin_loops; j++ )
{
aes_data_ptr =
aes_data_table[round_ctrl_table[ round_ctrl_table_len - 4 + j ] >> 4];
aes_data_ptr->xy_values[i] ^= *aes_data_ptr->rk_ptr++;
flow_control++;
}
}
aes_data_fake.xy_values[i] = mbedtls_platform_random_in_range( 0xffffffff );
flow_control++;
} while( ( i = ( i + 1 ) % 4 ) != offset );
for( i = 0; i < ( ctx->nr - 1 + AES_SCA_CM_ROUNDS ); i++ )
tindex = 0;
do
{
// Read AES control data
aes_data_ptr = aes_data_table[round_ctrl_table[i] >> 4];
offset = round_ctrl_table[i] & 0x0f;
// Get pointer to the real or fake data
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
stop_mark = round_ctrl_table[tindex] & 0x03;
// initial round key addition
for( i = 0; i < 4; i++ )
{
aes_data_ptr->xy_values[i] ^= *aes_data_ptr->rk_ptr++;
}
tindex++;
flow_control++;
} while( stop_mark == 0 );
// Calculate AES rounds (9, 11 or 13 rounds) + dummy rounds
do
{
// Get pointer to the real or fake data
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
offset = round_ctrl_table[tindex] & 0x04;
stop_mark = round_ctrl_table[tindex] & 0x03;
aes_data_ptr->rk_ptr = aes_rround( aes_data_ptr->rk_ptr,
&aes_data_ptr->xy_values[0 + offset],
@ -1286,12 +1392,15 @@ int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
aes_data_ptr->xy_values[5 - offset],
aes_data_ptr->xy_values[6 - offset],
aes_data_ptr->xy_values[7 - offset] );
tindex++;
flow_control++;
}
} while( stop_mark == 0 );
for( j = 0; j < start_fin_loops; j++ )
// Calculate final AES round + dummy rounds
do
{
aes_data_ptr = aes_data_table[round_ctrl_table[ i + j ] >> 4];
aes_data_ptr = aes_data_table[round_ctrl_table[tindex] >> 4];
stop_mark = round_ctrl_table[tindex] & 0x03;
aes_rround_final( aes_data_ptr->rk_ptr,
&aes_data_ptr->xy_values[0],
&aes_data_ptr->xy_values[1],
@ -1302,16 +1411,23 @@ int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
aes_data_ptr->xy_values[6],
aes_data_ptr->xy_values[7] );
flow_control++;
}
tindex++;
} while( stop_mark == 0 );
for( i = 0; i < 4; i++ )
// SCA countermeasure, safely clear the output
mbedtls_platform_memset( output, 0, 16 );
// SCA countermeasure, randomize secret data location by writing to it in
// a random order.
offset = mbedtls_platform_random_in_range( 4 );
i = offset;
do
{
PUT_UINT32_LE( aes_data_real.xy_values[i], output, ( i * 4 ) );
flow_control++;
}
} while( ( i = ( i + 1 ) % 4 ) != offset );
if( flow_control == ( AES_SCA_CM_ROUNDS + ( 4 * start_fin_loops ) +
ctx->nr - 1 + AES_SCA_CM_ROUNDS + start_fin_loops + 4 ) )
if( flow_control == tindex + dummy_rounds + 8 )
{
/* Validate control path due possible fault injection */
return 0;
@ -1319,6 +1435,88 @@ int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#else /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#define AES_RROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \
do \
{ \
(X0) = *RK++ ^ AES_RT0( ( (Y0) ) & 0xFF ) ^ \
AES_RT1( ( (Y3) >> 8 ) & 0xFF ) ^ \
AES_RT2( ( (Y2) >> 16 ) & 0xFF ) ^ \
AES_RT3( ( (Y1) >> 24 ) & 0xFF ); \
\
(X1) = *RK++ ^ AES_RT0( ( (Y1) ) & 0xFF ) ^ \
AES_RT1( ( (Y0) >> 8 ) & 0xFF ) ^ \
AES_RT2( ( (Y3) >> 16 ) & 0xFF ) ^ \
AES_RT3( ( (Y2) >> 24 ) & 0xFF ); \
\
(X2) = *RK++ ^ AES_RT0( ( (Y2) ) & 0xFF ) ^ \
AES_RT1( ( (Y1) >> 8 ) & 0xFF ) ^ \
AES_RT2( ( (Y0) >> 16 ) & 0xFF ) ^ \
AES_RT3( ( (Y3) >> 24 ) & 0xFF ); \
\
(X3) = *RK++ ^ AES_RT0( ( (Y3) ) & 0xFF ) ^ \
AES_RT1( ( (Y2) >> 8 ) & 0xFF ) ^ \
AES_RT2( ( (Y1) >> 16 ) & 0xFF ) ^ \
AES_RT3( ( (Y0) >> 24 ) & 0xFF ); \
} while( 0 )
int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
const unsigned char input[16],
unsigned char output[16] )
{
int i;
uint32_t *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;
RK = ctx->rk;
GET_UINT32_LE( X0, input, 0 ); X0 ^= *RK++;
GET_UINT32_LE( X1, input, 4 ); X1 ^= *RK++;
GET_UINT32_LE( X2, input, 8 ); X2 ^= *RK++;
GET_UINT32_LE( X3, input, 12 ); X3 ^= *RK++;
for( i = ( ctx->nr >> 1 ) - 1; i > 0; i-- )
{
AES_RROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
AES_RROUND( X0, X1, X2, X3, Y0, Y1, Y2, Y3 );
}
AES_RROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
X0 = *RK++ ^ \
( (uint32_t) RSb[ ( Y0 ) & 0xFF ] ) ^
( (uint32_t) RSb[ ( Y3 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) RSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) RSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );
X1 = *RK++ ^ \
( (uint32_t) RSb[ ( Y1 ) & 0xFF ] ) ^
( (uint32_t) RSb[ ( Y0 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) RSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) RSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );
X2 = *RK++ ^ \
( (uint32_t) RSb[ ( Y2 ) & 0xFF ] ) ^
( (uint32_t) RSb[ ( Y1 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) RSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) RSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );
X3 = *RK++ ^ \
( (uint32_t) RSb[ ( Y3 ) & 0xFF ] ) ^
( (uint32_t) RSb[ ( Y2 >> 8 ) & 0xFF ] << 8 ) ^
( (uint32_t) RSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
( (uint32_t) RSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );
PUT_UINT32_LE( X0, output, 0 );
PUT_UINT32_LE( X1, output, 4 );
PUT_UINT32_LE( X2, output, 8 );
PUT_UINT32_LE( X3, output, 12 );
return( 0 );
}
#endif /* MBEDTLS_AES_SCA_COUNTERMEASURES */
#endif /* !MBEDTLS_AES_ONLY_ENCRYPT */
#endif /* !MBEDTLS_AES_DECRYPT_ALT */