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Put local variables and buffers in a struct

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This reduces the impact of the code size increase due to the addition
of calls to mbedtls_platform_zeroize.

Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
This commit is contained in:
gabor-mezei-arm 2020-08-25 19:12:01 +02:00
parent b8513fa6ac
commit 4cb56f83cb
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GPG key ID: 106F5A41ECC305BD
6 changed files with 512 additions and 489 deletions
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99
library/sha256.c
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@ -181,83 +181,104 @@ static const uint32_t K[] =
#define F0(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
#define F1(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))
#define R(t) \
( \
W[t] = S1(W[(t) - 2]) + W[(t) - 7] + \
S0(W[(t) - 15]) + W[(t) - 16] \
#define R(t) \
( \
local.W[t] = S1(local.W[(t) - 2]) + local.W[(t) - 7] + \
S0(local.W[(t) - 15]) + local.W[(t) - 16] \
)
#define P(a,b,c,d,e,f,g,h,x,K) \
do \
{ \
temp1 = (h) + S3(e) + F1((e),(f),(g)) + (K) + (x); \
temp2 = S2(a) + F0((a),(b),(c)); \
(d) += temp1; (h) = temp1 + temp2; \
#define P(a,b,c,d,e,f,g,h,x,K) \
do \
{ \
local.temp1 = (h) + S3(e) + F1((e),(f),(g)) + (K) + (x); \
local.temp2 = S2(a) + F0((a),(b),(c)); \
(d) += local.temp1; (h) = local.temp1 + local.temp2; \
} while( 0 )
int mbedtls_internal_sha256_process( mbedtls_sha256_context *ctx,
const unsigned char data[64] )
{
uint32_t temp1, temp2, W[64];
uint32_t A[8];
struct
{
uint32_t temp1, temp2, W[64];
uint32_t A[8];
} local;
unsigned int i;
SHA256_VALIDATE_RET( ctx != NULL );
SHA256_VALIDATE_RET( (const unsigned char *)data != NULL );
for( i = 0; i < 8; i++ )
A[i] = ctx->state[i];
local.A[i] = ctx->state[i];
#if defined(MBEDTLS_SHA256_SMALLER)
for( i = 0; i < 64; i++ )
{
if( i < 16 )
GET_UINT32_BE( W[i], data, 4 * i );
GET_UINT32_BE( local.W[i], data, 4 * i );
else
R( i );
P( A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i], K[i] );
P( local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
local.A[5], local.A[6], local.A[7], local.W[i], K[i] );
temp1 = A[7]; A[7] = A[6]; A[6] = A[5]; A[5] = A[4]; A[4] = A[3];
A[3] = A[2]; A[2] = A[1]; A[1] = A[0]; A[0] = temp1;
local.temp1 = local.A[7]; local.A[7] = local.A[6];
local.A[6] = local.A[5]; local.A[5] = local.A[4];
local.A[4] = local.A[3]; local.A[3] = local.A[2];
local.A[2] = local.A[1]; local.A[1] = local.A[0];
local.A[0] = local.temp1;
}
#else /* MBEDTLS_SHA256_SMALLER */
for( i = 0; i < 16; i++ )
GET_UINT32_BE( W[i], data, 4 * i );
GET_UINT32_BE( local.W[i], data, 4 * i );
for( i = 0; i < 16; i += 8 )
{
P( A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i+0], K[i+0] );
P( A[7], A[0], A[1], A[2], A[3], A[4], A[5], A[6], W[i+1], K[i+1] );
P( A[6], A[7], A[0], A[1], A[2], A[3], A[4], A[5], W[i+2], K[i+2] );
P( A[5], A[6], A[7], A[0], A[1], A[2], A[3], A[4], W[i+3], K[i+3] );
P( A[4], A[5], A[6], A[7], A[0], A[1], A[2], A[3], W[i+4], K[i+4] );
P( A[3], A[4], A[5], A[6], A[7], A[0], A[1], A[2], W[i+5], K[i+5] );
P( A[2], A[3], A[4], A[5], A[6], A[7], A[0], A[1], W[i+6], K[i+6] );
P( A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[0], W[i+7], K[i+7] );
P( local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
local.A[5], local.A[6], local.A[7], local.W[i+0], K[i+0] );
P( local.A[7], local.A[0], local.A[1], local.A[2], local.A[3],
local.A[4], local.A[5], local.A[6], local.W[i+1], K[i+1] );
P( local.A[6], local.A[7], local.A[0], local.A[1], local.A[2],
local.A[3], local.A[4], local.A[5], local.W[i+2], K[i+2] );
P( local.A[5], local.A[6], local.A[7], local.A[0], local.A[1],
local.A[2], local.A[3], local.A[4], local.W[i+3], K[i+3] );
P( local.A[4], local.A[5], local.A[6], local.A[7], local.A[0],
local.A[1], local.A[2], local.A[3], local.W[i+4], K[i+4] );
P( local.A[3], local.A[4], local.A[5], local.A[6], local.A[7],
local.A[0], local.A[1], local.A[2], local.W[i+5], K[i+5] );
P( local.A[2], local.A[3], local.A[4], local.A[5], local.A[6],
local.A[7], local.A[0], local.A[1], local.W[i+6], K[i+6] );
P( local.A[1], local.A[2], local.A[3], local.A[4], local.A[5],
local.A[6], local.A[7], local.A[0], local.W[i+7], K[i+7] );
}
for( i = 16; i < 64; i += 8 )
{
P( A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], R(i+0), K[i+0] );
P( A[7], A[0], A[1], A[2], A[3], A[4], A[5], A[6], R(i+1), K[i+1] );
P( A[6], A[7], A[0], A[1], A[2], A[3], A[4], A[5], R(i+2), K[i+2] );
P( A[5], A[6], A[7], A[0], A[1], A[2], A[3], A[4], R(i+3), K[i+3] );
P( A[4], A[5], A[6], A[7], A[0], A[1], A[2], A[3], R(i+4), K[i+4] );
P( A[3], A[4], A[5], A[6], A[7], A[0], A[1], A[2], R(i+5), K[i+5] );
P( A[2], A[3], A[4], A[5], A[6], A[7], A[0], A[1], R(i+6), K[i+6] );
P( A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[0], R(i+7), K[i+7] );
P( local.A[0], local.A[1], local.A[2], local.A[3], local.A[4],
local.A[5], local.A[6], local.A[7], R(i+0), K[i+0] );
P( local.A[7], local.A[0], local.A[1], local.A[2], local.A[3],
local.A[4], local.A[5], local.A[6], R(i+1), K[i+1] );
P( local.A[6], local.A[7], local.A[0], local.A[1], local.A[2],
local.A[3], local.A[4], local.A[5], R(i+2), K[i+2] );
P( local.A[5], local.A[6], local.A[7], local.A[0], local.A[1],
local.A[2], local.A[3], local.A[4], R(i+3), K[i+3] );
P( local.A[4], local.A[5], local.A[6], local.A[7], local.A[0],
local.A[1], local.A[2], local.A[3], R(i+4), K[i+4] );
P( local.A[3], local.A[4], local.A[5], local.A[6], local.A[7],
local.A[0], local.A[1], local.A[2], R(i+5), K[i+5] );
P( local.A[2], local.A[3], local.A[4], local.A[5], local.A[6],
local.A[7], local.A[0], local.A[1], R(i+6), K[i+6] );
P( local.A[1], local.A[2], local.A[3], local.A[4], local.A[5],
local.A[6], local.A[7], local.A[0], R(i+7), K[i+7] );
}
#endif /* MBEDTLS_SHA256_SMALLER */
for( i = 0; i < 8; i++ )
ctx->state[i] += A[i];
ctx->state[i] += local.A[i];
/* Zeroise buffers and variables to clear sensitive data from memory. */
mbedtls_platform_zeroize( &A, sizeof( A ) );
mbedtls_platform_zeroize( &W, sizeof( W ) );
mbedtls_platform_zeroize( &temp1, sizeof( temp1 ) );
mbedtls_platform_zeroize( &temp2, sizeof( temp2 ) );
mbedtls_platform_zeroize( &local, sizeof( local ) );
return( 0 );
}