Make ECDH functions actually restartable
diff --git a/library/ecdh.c b/library/ecdh.c
index c0a8147..b2859c4 100644
--- a/library/ecdh.c
+++ b/library/ecdh.c
@@ -39,22 +39,48 @@
#include <string.h>
/*
- * Generate public key: simple wrapper around mbedtls_ecp_gen_keypair
+ * Generate public key (restartable version)
+ */
+static int ecdh_gen_public_restartable( mbedtls_ecp_group *grp,
+ mbedtls_mpi *d, mbedtls_ecp_point *Q,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
+{
+ int ret;
+
+ /* If multiplication is in progress, we already generated a privkey */
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx == NULL || rs_ctx->rsm == NULL )
+#endif
+ MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) );
+
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, Q, d, &grp->G,
+ f_rng, p_rng, rs_ctx ) );
+
+cleanup:
+ return( ret );
+}
+
+/*
+ * Generate public key
*/
int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
- return mbedtls_ecp_gen_keypair( grp, d, Q, f_rng, p_rng );
+ return( ecdh_gen_public_restartable( grp, d, Q, f_rng, p_rng, NULL ) );
}
/*
* Compute shared secret (SEC1 3.3.1)
*/
-int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
+static int ecdh_compute_shared_restartable( mbedtls_ecp_group *grp,
+ mbedtls_mpi *z,
const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng )
+ void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
mbedtls_ecp_point P;
@@ -66,7 +92,8 @@
*/
MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, Q ) );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &P, d, Q, f_rng, p_rng ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &P, d, Q,
+ f_rng, p_rng, rs_ctx ) );
if( mbedtls_ecp_is_zero( &P ) )
{
@@ -83,11 +110,27 @@
}
/*
+ * Compute shared secret (SEC1 3.3.1)
+ */
+int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
+ const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng )
+{
+ return( ecdh_compute_shared_restartable( grp, z, Q, d,
+ f_rng, p_rng, NULL ) );
+}
+
+/*
* Initialize context
*/
void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx )
{
memset( ctx, 0, sizeof( mbedtls_ecdh_context ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ mbedtls_ecp_restart_init( &ctx->rs );
+#endif
}
/*
@@ -106,6 +149,10 @@
mbedtls_mpi_free( &ctx->d );
mbedtls_mpi_free( &ctx->z );
mbedtls_mpi_free( &ctx->_d );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ mbedtls_ecp_restart_free( &ctx->rs );
+#endif
}
/*
@@ -122,12 +169,17 @@
{
int ret;
size_t grp_len, pt_len;
+ mbedtls_ecp_restart_ctx *rs_ctx = NULL;
if( ctx == NULL || ctx->grp.pbits == 0 )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
- if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
- != 0 )
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ rs_ctx = &ctx->rs;
+#endif
+
+ if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
+ f_rng, p_rng, rs_ctx ) ) != 0 )
return( ret );
if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf, blen ) )
@@ -202,12 +254,17 @@
void *p_rng )
{
int ret;
+ mbedtls_ecp_restart_ctx *rs_ctx = NULL;
if( ctx == NULL || ctx->grp.pbits == 0 )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
- if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
- != 0 )
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ rs_ctx = &ctx->rs;
+#endif
+
+ if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
+ f_rng, p_rng, rs_ctx ) ) != 0 )
return( ret );
return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
@@ -244,12 +301,17 @@
void *p_rng )
{
int ret;
+ mbedtls_ecp_restart_ctx *rs_ctx = NULL;
- if( ctx == NULL )
+ if( ctx == NULL || ctx->grp.pbits == 0 )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
- if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp, &ctx->d,
- f_rng, p_rng ) ) != 0 )
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ rs_ctx = &ctx->rs;
+#endif
+
+ if( ( ret = ecdh_compute_shared_restartable( &ctx->grp,
+ &ctx->z, &ctx->Qp, &ctx->d, f_rng, p_rng, rs_ctx ) ) != 0 )
{
return( ret );
}