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 37a01dd..986037a 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -243,8 +243,11 @@
const unsigned char data[128] )
{
int i;
- uint64_t temp1, temp2, W[80];
- uint64_t A, B, C, D, E, F, G, H;
+ struct
+ {
+ uint64_t temp1, temp2, W[80];
+ uint64_t A, B, C, D, E, F, G, H;
+ } local;
SHA512_VALIDATE_RET( ctx != NULL );
SHA512_VALIDATE_RET( (const unsigned char *)data != NULL );
@@ -261,69 +264,67 @@
#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 < 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];
}
- A = ctx->state[0];
- B = ctx->state[1];
- C = ctx->state[2];
- D = ctx->state[3];
- E = ctx->state[4];
- F = ctx->state[5];
- G = ctx->state[6];
- H = ctx->state[7];
+ local.A = ctx->state[0];
+ local.B = ctx->state[1];
+ local.C = ctx->state[2];
+ local.D = ctx->state[3];
+ local.E = ctx->state[4];
+ local.F = ctx->state[5];
+ local.G = ctx->state[6];
+ local.H = ctx->state[7];
i = 0;
do
{
- P( A, B, C, D, E, F, G, H, W[i], K[i] ); i++;
- P( H, A, B, C, D, E, F, G, W[i], K[i] ); i++;
- P( G, H, A, B, C, D, E, F, W[i], K[i] ); i++;
- P( F, G, H, A, B, C, D, E, W[i], K[i] ); i++;
- P( E, F, G, H, A, B, C, D, W[i], K[i] ); i++;
- P( D, E, F, G, H, A, B, C, W[i], K[i] ); i++;
- P( C, D, E, F, G, H, A, B, W[i], K[i] ); i++;
- P( B, C, D, E, F, G, H, A, W[i], K[i] ); i++;
+ P( local.A, local.B, local.C, local.D, local.E,
+ local.F, local.G, local.H, local.W[i], K[i] ); i++;
+ P( local.H, local.A, local.B, local.C, local.D,
+ local.E, local.F, local.G, local.W[i], K[i] ); i++;
+ P( local.G, local.H, local.A, local.B, local.C,
+ local.D, local.E, local.F, local.W[i], K[i] ); i++;
+ P( local.F, local.G, local.H, local.A, local.B,
+ local.C, local.D, local.E, local.W[i], K[i] ); i++;
+ P( local.E, local.F, local.G, local.H, local.A,
+ local.B, local.C, local.D, local.W[i], K[i] ); i++;
+ P( local.D, local.E, local.F, local.G, local.H,
+ local.A, local.B, local.C, local.W[i], K[i] ); i++;
+ P( local.C, local.D, local.E, local.F, local.G,
+ local.H, local.A, local.B, local.W[i], K[i] ); i++;
+ P( local.B, local.C, local.D, local.E, local.F,
+ local.G, local.H, local.A, local.W[i], K[i] ); i++;
}
while( i < 80 );
- ctx->state[0] += A;
- ctx->state[1] += B;
- ctx->state[2] += C;
- ctx->state[3] += D;
- ctx->state[4] += E;
- ctx->state[5] += F;
- ctx->state[6] += G;
- ctx->state[7] += H;
+ ctx->state[0] += local.A;
+ ctx->state[1] += local.B;
+ ctx->state[2] += local.C;
+ ctx->state[3] += local.D;
+ ctx->state[4] += local.E;
+ ctx->state[5] += local.F;
+ ctx->state[6] += local.G;
+ ctx->state[7] += local.H;
/* Zeroise buffers and variables to clear sensitive data from memory. */
- mbedtls_platform_zeroize( &A, sizeof( A ) );
- mbedtls_platform_zeroize( &B, sizeof( B ) );
- mbedtls_platform_zeroize( &C, sizeof( C ) );
- mbedtls_platform_zeroize( &D, sizeof( D ) );
- mbedtls_platform_zeroize( &E, sizeof( E ) );
- mbedtls_platform_zeroize( &F, sizeof( F ) );
- mbedtls_platform_zeroize( &G, sizeof( G ) );
- mbedtls_platform_zeroize( &H, sizeof( H ) );
- 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 );
}