diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h index d2f83b224..f557a4de2 100644 --- a/include/mbedtls/ecdsa.h +++ b/include/mbedtls/ecdsa.h @@ -187,6 +187,35 @@ int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ); +/** + * \brief Restartable version of \c mbedtls_ecdsa_write_signature() + * + * \note Performs the same job as \c mbedtls_ecdsa_write_signature() + * but can return early and restart according to the limit + * set with \c mbedtls_ecp_set_max_ops() to reduce blocking. + * + * \param ctx ECDSA context + * \param md_alg Algorithm that was used to hash the message + * \param hash Message hash + * \param hlen Length of hash + * \param sig Buffer that will hold the signature + * \param slen Length of the signature written + * \param f_rng RNG function + * \param p_rng RNG parameter + * \param rs_ctx Restart context + * + * \return See \c mbedtls_ecdsa_write_signature(), or + * MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of + * operations was reached: see \c mbedtls_ecp_set_max_ops(). + */ +int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx, + mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hlen, + unsigned char *sig, size_t *slen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecdsa_restart_ctx *rs_ctx ); + #if defined(MBEDTLS_ECDSA_DETERMINISTIC) #if ! defined(MBEDTLS_DEPRECATED_REMOVED) #if defined(MBEDTLS_DEPRECATED_WARNING) diff --git a/library/ecdsa.c b/library/ecdsa.c index f7f7a01af..ec1e5872d 100644 --- a/library/ecdsa.c +++ b/library/ecdsa.c @@ -127,14 +127,18 @@ cleanup: * Compute ECDSA signature of a hashed message (SEC1 4.1.3) * Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message) */ -int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s, +static int ecdsa_sign_restartable( mbedtls_ecp_group *grp, + mbedtls_mpi *r, mbedtls_mpi *s, const mbedtls_mpi *d, const unsigned char *buf, size_t blen, - int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, + mbedtls_ecdsa_restart_ctx *rs_ctx ) { int ret, key_tries, sign_tries, blind_tries; mbedtls_ecp_point R; mbedtls_mpi k, e, t; + (void) rs_ctx; // temporary + /* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */ if( grp->N.p == NULL ) return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); @@ -212,13 +216,26 @@ cleanup: return( ret ); } +/* + * Compute ECDSA signature of a hashed message + */ +int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s, + const mbedtls_mpi *d, const unsigned char *buf, size_t blen, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) +{ + return( ecdsa_sign_restartable( grp, r, s, d, buf, blen, + f_rng, p_rng, NULL ) ); +} + #if defined(MBEDTLS_ECDSA_DETERMINISTIC) /* * Deterministic signature wrapper */ -int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s, +static int ecdsa_sign_det_restartable( mbedtls_ecp_group *grp, + mbedtls_mpi *r, mbedtls_mpi *s, const mbedtls_mpi *d, const unsigned char *buf, size_t blen, - mbedtls_md_type_t md_alg ) + mbedtls_md_type_t md_alg, + mbedtls_ecdsa_restart_ctx *rs_ctx ) { int ret; mbedtls_hmac_drbg_context rng_ctx; @@ -227,6 +244,8 @@ int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi const mbedtls_md_info_t *md_info; mbedtls_mpi h; + (void) rs_ctx; // temporary + if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL ) return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); @@ -248,6 +267,16 @@ cleanup: return( ret ); } + +/* + * Deterministic signature wrapper + */ +int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s, + const mbedtls_mpi *d, const unsigned char *buf, size_t blen, + mbedtls_md_type_t md_alg ) +{ + return( ecdsa_sign_det_restartable( grp, r, s, d, buf, blen, md_alg, NULL ) ); +} #endif /* MBEDTLS_ECDSA_DETERMINISTIC */ /* @@ -427,11 +456,13 @@ static int ecdsa_signature_to_asn1( const mbedtls_mpi *r, const mbedtls_mpi *s, /* * Compute and write signature */ -int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg, +int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx, + mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hlen, unsigned char *sig, size_t *slen, int (*f_rng)(void *, unsigned char *, size_t), - void *p_rng ) + void *p_rng, + mbedtls_ecdsa_restart_ctx *rs_ctx ) { int ret; mbedtls_mpi r, s; @@ -443,13 +474,13 @@ int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t (void) f_rng; (void) p_rng; - MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign_det( &ctx->grp, &r, &s, &ctx->d, - hash, hlen, md_alg ) ); + MBEDTLS_MPI_CHK( ecdsa_sign_det_restartable( &ctx->grp, &r, &s, &ctx->d, + hash, hlen, md_alg, rs_ctx ) ); #else (void) md_alg; - MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign( &ctx->grp, &r, &s, &ctx->d, - hash, hlen, f_rng, p_rng ) ); + MBEDTLS_MPI_CHK( ecdsa_sign_restartable( &ctx->grp, &r, &s, &ctx->d, + hash, hlen, f_rng, p_rng, rs_ctx ) ); #endif MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) ); @@ -461,6 +492,19 @@ cleanup: return( ret ); } +/* + * Compute and write signature + */ +int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hlen, + unsigned char *sig, size_t *slen, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) +{ + return( mbedtls_ecdsa_write_signature_restartable( + ctx, md_alg, hash, hlen, sig, slen, f_rng, p_rng, NULL ) ); +} + #if ! defined(MBEDTLS_DEPRECATED_REMOVED) && \ defined(MBEDTLS_ECDSA_DETERMINISTIC) int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,