From 82cb27b3db2b15e32937cbca9474afbd9e2ccd5b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?= Date: Wed, 3 May 2017 10:59:45 +0200 Subject: [PATCH] PK: declare restartable sign/verify functions For RSA, we could either have the function return an error code like NOT_IMPLEMENTED or just run while disregarding ecp_max_ops. IMO the second option makes more sense, as otherwise the caller would need to check whether the key is EC or RSA before deciding to call either sign() or sign_restartable(), and having to do this kind of check feels contrary to the goal of the PK layer. --- include/mbedtls/pk.h | 57 ++++++++++++++++++++++++++++++++++++++++++++ library/pk.c | 43 ++++++++++++++++++++++++++++----- 2 files changed, 94 insertions(+), 6 deletions(-) diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h index f9f9b9bb0..05c51d38d 100644 --- a/include/mbedtls/pk.h +++ b/include/mbedtls/pk.h @@ -284,6 +284,33 @@ int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len ); +/** + * \brief Restartable version of \c mbedtls_pk_verify() + * + * \note Performs the same job as \c mbedtls_pk_verify(), but can + * return early and restart according to the limit set with + * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC + * operations. For RSA, same as \c mbedtls_pk_verify(). + * + * \param ctx PK context to use + * \param md_alg Hash algorithm used (see notes) + * \param hash Hash of the message to sign + * \param hash_len Hash length or 0 (see notes) + * \param sig Signature to verify + * \param sig_len Signature length + * \param rs_ctx Restart context: for ECC, must be NULL (no restart) or a + * pointer to a \c mbedtls_ecdsa_restart_ctx. Ignored for RSA. + * + * \return See \c mbedtls_pk_verify(), or + * MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of + * operations was reached: see \c mbedtls_ecp_set_max_ops(). + */ +int mbedtls_pk_verify_restartable( mbedtls_pk_context *ctx, + mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hash_len, + const unsigned char *sig, size_t sig_len, + void *rs_ctx ); + /** * \brief Verify signature, with options. * (Includes verification of the padding depending on type.) @@ -347,6 +374,36 @@ int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, unsigned char *sig, size_t *sig_len, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ); +/** + * \brief Restartable version of \c mbedtls_pk_sign() + * + * \note Performs the same job as \c mbedtls_pk_sign(), but can + * return early and restart according to the limit set with + * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC + * operations. For RSA, same as \c mbedtls_pk_sign(). + * + * \param ctx PK context to use - must hold a private key + * \param md_alg Hash algorithm used (see notes) + * \param hash Hash of the message to sign + * \param hash_len Hash length or 0 (see notes) + * \param sig Place to write the signature + * \param sig_len Number of bytes written + * \param f_rng RNG function + * \param p_rng RNG parameter + * \param rs_ctx Restart context: for ECC, must be NULL (no restart) or a + * pointer to a \c mbedtls_ecdsa_restart_ctx. Ignored for RSA. + * + * \return See \c mbedtls_pk_sign(), or + * MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of + * operations was reached: see \c mbedtls_ecp_set_max_ops(). + */ +int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx, + mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hash_len, + unsigned char *sig, size_t *sig_len, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, + void *rs_ctx ); + /** * \brief Decrypt message (including padding if relevant). * diff --git a/library/pk.c b/library/pk.c index 8d13bc5ce..b5081f961 100644 --- a/library/pk.c +++ b/library/pk.c @@ -176,12 +176,16 @@ static inline int pk_hashlen_helper( mbedtls_md_type_t md_alg, size_t *hash_len } /* - * Verify a signature + * Verify a signature (restartable) */ -int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, +int mbedtls_pk_verify_restartable( mbedtls_pk_context *ctx, + mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, - const unsigned char *sig, size_t sig_len ) + const unsigned char *sig, size_t sig_len, + void *rs_ctx ) { + (void) rs_ctx; // XXX temporary + if( ctx == NULL || ctx->pk_info == NULL || pk_hashlen_helper( md_alg, &hash_len ) != 0 ) return( MBEDTLS_ERR_PK_BAD_INPUT_DATA ); @@ -193,6 +197,17 @@ int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, sig, sig_len ) ); } +/* + * Verify a signature + */ +int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hash_len, + const unsigned char *sig, size_t sig_len ) +{ + return( mbedtls_pk_verify_restartable( ctx, md_alg, hash, hash_len, + sig, sig_len, NULL ) ); +} + /* * Verify a signature with options */ @@ -252,13 +267,17 @@ int mbedtls_pk_verify_ext( mbedtls_pk_type_t type, const void *options, } /* - * Make a signature + * Make a signature (restartable) */ -int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, +int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx, + mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, unsigned char *sig, size_t *sig_len, - int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, + void *rs_ctx ) { + (void) rs_ctx; // XXX temporary + if( ctx == NULL || ctx->pk_info == NULL || pk_hashlen_helper( md_alg, &hash_len ) != 0 ) return( MBEDTLS_ERR_PK_BAD_INPUT_DATA ); @@ -270,6 +289,18 @@ int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, sig, sig_len, f_rng, p_rng ) ); } +/* + * Make a signature + */ +int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, + const unsigned char *hash, size_t hash_len, + unsigned char *sig, size_t *sig_len, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) +{ + return( mbedtls_pk_sign_restartable( ctx, md_alg, hash, hash_len, + sig, sig_len, f_rng, p_rng, NULL ) ); +} + /* * Decrypt message */