ECP: Use explicit state assignments

Incrementing the state is error-prone as we can end up doing it too many times
(loops) or not enough (skipped branches), or just make programming mistakes
(eg. the state was incremented twice at the end, so it ended up with a value
not in the enum...)

This is the first step of the rework, the next one will rationalize where the
state assignments are done.
This commit is contained in:
Manuel Pégourié-Gonnard 2017-08-24 10:25:06 +02:00
parent db4a8eb992
commit c9efa00871

View file

@ -1563,7 +1563,7 @@ static int ecp_precompute_comb( const mbedtls_ecp_group *grp,
if( rs_ctx != NULL && rs_ctx->rsm != NULL )
{
rs_ctx->rsm->i = 0;
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_pre_norm_dbl;
}
#endif
@ -1585,7 +1585,7 @@ norm_dbl:
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->rsm != NULL )
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_pre_add;
#endif
/*
@ -1607,7 +1607,7 @@ add:
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->rsm != NULL )
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_pre_norm_add;
#endif
/*
@ -1628,7 +1628,7 @@ norm_add:
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->rsm != NULL )
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_T_done;
#endif
cleanup:
@ -1730,7 +1730,7 @@ cleanup:
{
if( ret == 0 )
{
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_final_norm;
rs_ctx->rsm->i = 0;
}
else if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
@ -1834,7 +1834,7 @@ static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp,
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->rsm != NULL )
rs_ctx->rsm->state++;
rs_ctx->rsm->state = ecp_rsm_final_norm;
#endif
}
@ -2420,14 +2420,14 @@ int mbedtls_ecp_muladd_restartable(
MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, pmP, m, P, rs_ctx ) );
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->ma != NULL )
rs_ctx->ma->state++;
rs_ctx->ma->state = ecp_rsma_mul2;
mul2:
#endif
MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, pR, n, Q, rs_ctx ) );
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->ma != NULL )
rs_ctx->ma->state++;
rs_ctx->ma->state = ecp_rsma_add;
add:
#endif
@ -2435,7 +2435,7 @@ add:
MBEDTLS_MPI_CHK( ecp_add_mixed( grp, pR, pmP, pR ) );
#if defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && rs_ctx->ma != NULL )
rs_ctx->ma->state++;
rs_ctx->ma->state = ecp_rsma_norm;
norm:
#endif