Put local variables and buffers in a struct
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>
diff --git a/library/sha512.c b/library/sha512.c
index 08f4dd5..e08a2e3 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -234,8 +234,11 @@
const unsigned char data[128] )
{
int i;
- uint64_t temp1, temp2, W[80];
- uint64_t A[8];
+ struct
+ {
+ uint64_t temp1, temp2, W[80];
+ uint64_t A[8];
+ } local;
SHA512_VALIDATE_RET( ctx != NULL );
SHA512_VALIDATE_RET( (const unsigned char *)data != NULL );
@@ -252,70 +255,79 @@
#define F0(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
#define F1(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))
-#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 )
for( i = 0; i < 8; i++ )
- A[i] = ctx->state[i];
+ local.A[i] = ctx->state[i];
#if defined(MBEDTLS_SHA512_SMALLER)
for( i = 0; i < 80; i++ )
{
if( i < 16 )
{
- GET_UINT64_BE( W[i], data, i << 3 );
+ GET_UINT64_BE( local.W[i], data, i << 3 );
}
else
{
- W[i] = S1(W[i - 2]) + W[i - 7] +
- S0(W[i - 15]) + W[i - 16];
+ local.W[i] = S1(local.W[i - 2]) + local.W[i - 7] +
+ S0(local.W[i - 15]) + local.W[i - 16];
}
- 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_SHA512_SMALLER */
for( i = 0; i < 16; i++ )
{
- GET_UINT64_BE( W[i], data, i << 3 );
+ GET_UINT64_BE( local.W[i], data, i << 3 );
}
for( ; i < 80; i++ )
{
- W[i] = S1(W[i - 2]) + W[i - 7] +
- S0(W[i - 15]) + W[i - 16];
+ local.W[i] = S1(local.W[i - 2]) + local.W[i - 7] +
+ S0(local.W[i - 15]) + local.W[i - 16];
}
i = 0;
do
{
- P( A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i], K[i] ); i++;
- P( A[7], A[0], A[1], A[2], A[3], A[4], A[5], A[6], W[i], K[i] ); i++;
- P( A[6], A[7], A[0], A[1], A[2], A[3], A[4], A[5], W[i], K[i] ); i++;
- P( A[5], A[6], A[7], A[0], A[1], A[2], A[3], A[4], W[i], K[i] ); i++;
- P( A[4], A[5], A[6], A[7], A[0], A[1], A[2], A[3], W[i], K[i] ); i++;
- P( A[3], A[4], A[5], A[6], A[7], A[0], A[1], A[2], W[i], K[i] ); i++;
- P( A[2], A[3], A[4], A[5], A[6], A[7], A[0], A[1], W[i], K[i] ); i++;
- P( A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[0], W[i], K[i] ); 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] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
+ 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], K[i] ); i++;
}
while( i < 80 );
#endif /* MBEDTLS_SHA512_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 );
}
