Add infrastructure for ecdsa_verify_restartable()

This commit is contained in:
Manuel Pégourié-Gonnard 2017-04-21 11:33:57 +02:00
parent 722e5156fd
commit a0c5bcc2bc
4 changed files with 107 additions and 2 deletions

View file

@ -42,6 +42,50 @@
#include "mbedtls/hmac_drbg.h"
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#if defined(MBEDTLS_ECP_RESTARTABLE)
/*
* Sub-contect for ecdsa_verify()
*/
struct mbedtls_ecdsa_restart_ver
{
int state; /* dummy */
};
/*
* Init verify restart sub-context
*/
static void ecdsa_restart_ver_init( mbedtls_ecdsa_restart_ver_ctx *ctx )
{
memset( ctx, 0, sizeof( *ctx ) );
}
/*
* Free the components of a verify restart sub-context
*/
static void ecdsa_restart_ver_free( mbedtls_ecdsa_restart_ver_ctx *ctx )
{
if( ctx == NULL )
return;
memset( ctx, 0, sizeof( *ctx ) );
}
#define ECDSA_RS_ECP &rs_ctx->ecp
#else /* MBEDTLS_ECP_RESTARTABLE */
#define ECDSA_RS_ECP NULL
#endif /* MBEDTLS_ECP_RESTARTABLE */
/*
* Derive a suitable integer for group grp from a buffer of length len
* SEC1 4.1.3 step 5 aka SEC1 4.1.4 step 3
@ -206,7 +250,9 @@ static int ecdsa_verify_restartable( mbedtls_ecp_group *grp,
mbedtls_mpi e, s_inv, u1, u2;
mbedtls_ecp_point R;
(void) rs_ctx; // temporary
#if !defined(MBEDTLS_ECP_RESTARTABLE)
(void) rs_ctx;
#endif
mbedtls_ecp_point_init( &R );
mbedtls_mpi_init( &e ); mbedtls_mpi_init( &s_inv );
@ -216,6 +262,22 @@ static int ecdsa_verify_restartable( mbedtls_ecp_group *grp,
if( grp->N.p == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
#if defined(MBEDTLS_ECP_RESTARTABLE)
/* reset ops count for this call if top-level */
if( rs_ctx != NULL && rs_ctx->ecp.depth++ == 0 )
rs_ctx->ecp.ops_done = 0;
/* set up our own sub-context if needed */
if( mbedtls_ecp_restart_enabled() && rs_ctx != NULL && rs_ctx->ver == NULL )
{
rs_ctx->ver = mbedtls_calloc( 1, sizeof( mbedtls_ecdsa_restart_ver_ctx ) );
if( rs_ctx->ver == NULL )
return( MBEDTLS_ERR_ECP_ALLOC_FAILED );
ecdsa_restart_ver_init( rs_ctx->ver );
}
#endif /* MBEDTLS_ECP_RESTARTABLE */
/*
* Step 1: make sure r and s are in range 1..n-1
*/
@ -250,7 +312,8 @@ static int ecdsa_verify_restartable( mbedtls_ecp_group *grp,
/*
* Step 5: R = u1 G + u2 Q
*/
MBEDTLS_MPI_CHK( mbedtls_ecp_muladd( grp, &R, &u1, &grp->G, &u2, Q ) );
MBEDTLS_MPI_CHK( mbedtls_ecp_muladd_restartable( grp,
&R, &u1, &grp->G, &u2, Q, ECDSA_RS_ECP ) );
if( mbedtls_ecp_is_zero( &R ) )
{
@ -278,6 +341,18 @@ cleanup:
mbedtls_mpi_free( &e ); mbedtls_mpi_free( &s_inv );
mbedtls_mpi_free( &u1 ); mbedtls_mpi_free( &u2 );
#if defined(MBEDTLS_ECP_RESTARTABLE)
/* clear our sub-context when not in progress (done or error) */
if( rs_ctx != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) {
ecdsa_restart_ver_free( rs_ctx->ver );
mbedtls_free( rs_ctx->ver );
rs_ctx->ver = NULL;
}
if( rs_ctx != NULL )
rs_ctx->ecp.depth--;
#endif /* MBEDTLS_ECP_RESTARTABLE */
return( ret );
}
@ -477,6 +552,8 @@ void mbedtls_ecdsa_free( mbedtls_ecdsa_context *ctx )
void mbedtls_ecdsa_restart_init( mbedtls_ecdsa_restart_ctx *ctx )
{
mbedtls_ecp_restart_init( &ctx->ecp );
ctx->ver = NULL;
}
/*
@ -485,6 +562,10 @@ void mbedtls_ecdsa_restart_init( mbedtls_ecdsa_restart_ctx *ctx )
void mbedtls_ecdsa_restart_free( mbedtls_ecdsa_restart_ctx *ctx )
{
mbedtls_ecp_restart_free( &ctx->ecp );
ecdsa_restart_ver_free( ctx->ver );
mbedtls_free( ctx->ver );
ctx->ver = NULL;
}
#endif /* MBEDTLS_ECP_RESTARTABLE */