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/md4.c b/library/md4.c
index 28e81c8..160a814 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -147,51 +147,54 @@
int mbedtls_internal_md4_process( mbedtls_md4_context *ctx,
const unsigned char data[64] )
{
- uint32_t X[16], A, B, C, D;
+ struct
+ {
+ uint32_t X[16], A, B, C, D;
+ } local;
- GET_UINT32_LE( X[ 0], data, 0 );
- GET_UINT32_LE( X[ 1], data, 4 );
- GET_UINT32_LE( X[ 2], data, 8 );
- GET_UINT32_LE( X[ 3], data, 12 );
- GET_UINT32_LE( X[ 4], data, 16 );
- GET_UINT32_LE( X[ 5], data, 20 );
- GET_UINT32_LE( X[ 6], data, 24 );
- GET_UINT32_LE( X[ 7], data, 28 );
- GET_UINT32_LE( X[ 8], data, 32 );
- GET_UINT32_LE( X[ 9], data, 36 );
- GET_UINT32_LE( X[10], data, 40 );
- GET_UINT32_LE( X[11], data, 44 );
- GET_UINT32_LE( X[12], data, 48 );
- GET_UINT32_LE( X[13], data, 52 );
- GET_UINT32_LE( X[14], data, 56 );
- GET_UINT32_LE( X[15], data, 60 );
+ GET_UINT32_LE( local.X[ 0], data, 0 );
+ GET_UINT32_LE( local.X[ 1], data, 4 );
+ GET_UINT32_LE( local.X[ 2], data, 8 );
+ GET_UINT32_LE( local.X[ 3], data, 12 );
+ GET_UINT32_LE( local.X[ 4], data, 16 );
+ GET_UINT32_LE( local.X[ 5], data, 20 );
+ GET_UINT32_LE( local.X[ 6], data, 24 );
+ GET_UINT32_LE( local.X[ 7], data, 28 );
+ GET_UINT32_LE( local.X[ 8], data, 32 );
+ GET_UINT32_LE( local.X[ 9], data, 36 );
+ GET_UINT32_LE( local.X[10], data, 40 );
+ GET_UINT32_LE( local.X[11], data, 44 );
+ GET_UINT32_LE( local.X[12], data, 48 );
+ GET_UINT32_LE( local.X[13], data, 52 );
+ GET_UINT32_LE( local.X[14], data, 56 );
+ GET_UINT32_LE( local.X[15], data, 60 );
#define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))
- A = ctx->state[0];
- B = ctx->state[1];
- C = ctx->state[2];
- D = ctx->state[3];
+ local.A = ctx->state[0];
+ local.B = ctx->state[1];
+ local.C = ctx->state[2];
+ local.D = ctx->state[3];
#define F(x, y, z) ((x & y) | ((~x) & z))
#define P(a,b,c,d,x,s) { a += F(b,c,d) + x; a = S(a,s); }
- P( A, B, C, D, X[ 0], 3 );
- P( D, A, B, C, X[ 1], 7 );
- P( C, D, A, B, X[ 2], 11 );
- P( B, C, D, A, X[ 3], 19 );
- P( A, B, C, D, X[ 4], 3 );
- P( D, A, B, C, X[ 5], 7 );
- P( C, D, A, B, X[ 6], 11 );
- P( B, C, D, A, X[ 7], 19 );
- P( A, B, C, D, X[ 8], 3 );
- P( D, A, B, C, X[ 9], 7 );
- P( C, D, A, B, X[10], 11 );
- P( B, C, D, A, X[11], 19 );
- P( A, B, C, D, X[12], 3 );
- P( D, A, B, C, X[13], 7 );
- P( C, D, A, B, X[14], 11 );
- P( B, C, D, A, X[15], 19 );
+ P( local.A, local.B, local.C, local.D, local.X[ 0], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 1], 7 );
+ P( local.C, local.D, local.A, local.B, local.X[ 2], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[ 3], 19 );
+ P( local.A, local.B, local.C, local.D, local.X[ 4], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 5], 7 );
+ P( local.C, local.D, local.A, local.B, local.X[ 6], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[ 7], 19 );
+ P( local.A, local.B, local.C, local.D, local.X[ 8], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 9], 7 );
+ P( local.C, local.D, local.A, local.B, local.X[10], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[11], 19 );
+ P( local.A, local.B, local.C, local.D, local.X[12], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[13], 7 );
+ P( local.C, local.D, local.A, local.B, local.X[14], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[15], 19 );
#undef P
#undef F
@@ -199,22 +202,22 @@
#define F(x,y,z) ((x & y) | (x & z) | (y & z))
#define P(a,b,c,d,x,s) { a += F(b,c,d) + x + 0x5A827999; a = S(a,s); }
- P( A, B, C, D, X[ 0], 3 );
- P( D, A, B, C, X[ 4], 5 );
- P( C, D, A, B, X[ 8], 9 );
- P( B, C, D, A, X[12], 13 );
- P( A, B, C, D, X[ 1], 3 );
- P( D, A, B, C, X[ 5], 5 );
- P( C, D, A, B, X[ 9], 9 );
- P( B, C, D, A, X[13], 13 );
- P( A, B, C, D, X[ 2], 3 );
- P( D, A, B, C, X[ 6], 5 );
- P( C, D, A, B, X[10], 9 );
- P( B, C, D, A, X[14], 13 );
- P( A, B, C, D, X[ 3], 3 );
- P( D, A, B, C, X[ 7], 5 );
- P( C, D, A, B, X[11], 9 );
- P( B, C, D, A, X[15], 13 );
+ P( local.A, local.B, local.C, local.D, local.X[ 0], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 4], 5 );
+ P( local.C, local.D, local.A, local.B, local.X[ 8], 9 );
+ P( local.B, local.C, local.D, local.A, local.X[12], 13 );
+ P( local.A, local.B, local.C, local.D, local.X[ 1], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 5], 5 );
+ P( local.C, local.D, local.A, local.B, local.X[ 9], 9 );
+ P( local.B, local.C, local.D, local.A, local.X[13], 13 );
+ P( local.A, local.B, local.C, local.D, local.X[ 2], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 6], 5 );
+ P( local.C, local.D, local.A, local.B, local.X[10], 9 );
+ P( local.B, local.C, local.D, local.A, local.X[14], 13 );
+ P( local.A, local.B, local.C, local.D, local.X[ 3], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 7], 5 );
+ P( local.C, local.D, local.A, local.B, local.X[11], 9 );
+ P( local.B, local.C, local.D, local.A, local.X[15], 13 );
#undef P
#undef F
@@ -222,37 +225,33 @@
#define F(x,y,z) (x ^ y ^ z)
#define P(a,b,c,d,x,s) { a += F(b,c,d) + x + 0x6ED9EBA1; a = S(a,s); }
- P( A, B, C, D, X[ 0], 3 );
- P( D, A, B, C, X[ 8], 9 );
- P( C, D, A, B, X[ 4], 11 );
- P( B, C, D, A, X[12], 15 );
- P( A, B, C, D, X[ 2], 3 );
- P( D, A, B, C, X[10], 9 );
- P( C, D, A, B, X[ 6], 11 );
- P( B, C, D, A, X[14], 15 );
- P( A, B, C, D, X[ 1], 3 );
- P( D, A, B, C, X[ 9], 9 );
- P( C, D, A, B, X[ 5], 11 );
- P( B, C, D, A, X[13], 15 );
- P( A, B, C, D, X[ 3], 3 );
- P( D, A, B, C, X[11], 9 );
- P( C, D, A, B, X[ 7], 11 );
- P( B, C, D, A, X[15], 15 );
+ P( local.A, local.B, local.C, local.D, local.X[ 0], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 8], 9 );
+ P( local.C, local.D, local.A, local.B, local.X[ 4], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[12], 15 );
+ P( local.A, local.B, local.C, local.D, local.X[ 2], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[10], 9 );
+ P( local.C, local.D, local.A, local.B, local.X[ 6], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[14], 15 );
+ P( local.A, local.B, local.C, local.D, local.X[ 1], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[ 9], 9 );
+ P( local.C, local.D, local.A, local.B, local.X[ 5], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[13], 15 );
+ P( local.A, local.B, local.C, local.D, local.X[ 3], 3 );
+ P( local.D, local.A, local.B, local.C, local.X[11], 9 );
+ P( local.C, local.D, local.A, local.B, local.X[ 7], 11 );
+ P( local.B, local.C, local.D, local.A, local.X[15], 15 );
#undef F
#undef P
- ctx->state[0] += A;
- ctx->state[1] += B;
- ctx->state[2] += C;
- ctx->state[3] += D;
+ ctx->state[0] += local.A;
+ ctx->state[1] += local.B;
+ ctx->state[2] += local.C;
+ ctx->state[3] += local.D;
/* Zeroise variables to clear sensitive data from memory. */
- mbedtls_zeroize( &X, sizeof( X ) );
- mbedtls_zeroize( &A, sizeof( A ) );
- mbedtls_zeroize( &B, sizeof( B ) );
- mbedtls_zeroize( &C, sizeof( C ) );
- mbedtls_zeroize( &D, sizeof( D ) );
+ mbedtls_zeroize( &local, sizeof( local ) );
return( 0 );
}