From 0724ce514d1fb8bb41ea339978f08f9eb8deeed7 Mon Sep 17 00:00:00 2001 From: Kamil Sroka Date: Thu, 20 Dec 2018 18:11:56 +0100 Subject: [PATCH] [nrf52840] fix build with ECDSA=1 (#3388) --- .../libraries/crypto/ecp_alt_cc310.c | 1717 +++++++++++++---- 1 file changed, 1289 insertions(+), 428 deletions(-) diff --git a/third_party/NordicSemiconductor/libraries/crypto/ecp_alt_cc310.c b/third_party/NordicSemiconductor/libraries/crypto/ecp_alt_cc310.c index 9baa073c0..9ebff782e 100644 --- a/third_party/NordicSemiconductor/libraries/crypto/ecp_alt_cc310.c +++ b/third_party/NordicSemiconductor/libraries/crypto/ecp_alt_cc310.c @@ -24,7 +24,9 @@ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. - * + */ + +/* * Elliptic curves over GF(p): generic functions * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved @@ -41,6 +43,8 @@ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. + * + * This file is part of mbed TLS (https://tls.mbed.org) */ /* @@ -65,54 +69,34 @@ * */ + /* + * Changes to original file: + * - Hardware accelerated EC point multiplication. + * - Hardware accelerated EC key pair generation. + * + * Added lines [496 - 749] + * Changed code in [2620 - 2631] + * Changed code in [3005 - 3013] + * + * Original file (ecp.c) from d369956d42764dc8173a8bf8106ed0f1defedec6 + */ + + #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif -#if defined(MBEDTLS_ECP_ALT) +#if defined(MBEDTLS_ECP_C) #include "mbedtls/ecp.h" #include "mbedtls/threading.h" +#include "mbedtls/platform_util.h" #include -#include "cc310_mbedtls.h" -#include "crys_ecpki_kg.h" -#include "crys_ecpki_domain.h" -#include "crys_rnd.h" -#include "ssi_bitops.h" - -extern CRYSError_t PkaEcWrstScalarMult(const CRYS_ECPKI_Domain_t *pDomain, - const uint32_t *scalar, - uint32_t scalSizeInWords, - uint32_t *inPointX, - uint32_t *inPointY, - uint32_t *outPointX, - uint32_t *outPointY, - uint32_t *tmpBuff); - -extern CRYS_RND_State_t * pRndState; - -#define CC_CALLOC_CHECK(ptr, size) \ -do \ -{ \ - if (( ptr = mbedtls_calloc( 1, size ) ) == NULL ) \ - { \ - ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; \ - goto cleanup; \ - } \ -} while (0) - -#define CC_CHECK_FREE(ptr) \ -do \ -{ \ - if (ptr != NULL) \ - { \ - mbedtls_free( ptr ); \ - } \ -} while (0) +#if defined(MBEDTLS_ECP_ALT) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" @@ -120,7 +104,7 @@ do \ #include #include #define mbedtls_printf printf -#define mbedtls_calloc calloc +#define mbedtls_calloc calloc #define mbedtls_free free #endif @@ -131,11 +115,6 @@ do \ #define inline __inline #endif -/* Implementation that should never be optimized out by the compiler */ -static void mbedtls_zeroize( void *v, size_t n ) { - volatile unsigned char *p = v; while( n-- ) *p++ = 0; -} - #if defined(MBEDTLS_SELF_TEST) /* * Counts of point addition and doubling, and field multiplications. @@ -144,6 +123,294 @@ static void mbedtls_zeroize( void *v, size_t n ) { static unsigned long add_count, dbl_count, mul_count; #endif +#if defined(MBEDTLS_ECP_RESTARTABLE) + +/** + * \brief Internal restart context for multiplication + * + * \note Opaque struct + */ +typedef struct mbedtls_ecp_restart_mul mbedtls_ecp_restart_mul_ctx; + +/** + * \brief Internal restart context for ecp_muladd() + * + * \note Opaque struct + */ +typedef struct mbedtls_ecp_restart_muladd mbedtls_ecp_restart_muladd_ctx; + +/** + * \brief General context for resuming ECC operations + */ +typedef struct +{ + unsigned ops_done; /*!< current ops count */ + unsigned depth; /*!< call depth (0 = top-level) */ + mbedtls_ecp_restart_mul_ctx *rsm; /*!< ecp_mul_comb() sub-context */ + mbedtls_ecp_restart_muladd_ctx *ma; /*!< ecp_muladd() sub-context */ +} mbedtls_ecp_restart_ctx; + +/* + * Operation counts for restartable functions + */ +#define MBEDTLS_ECP_OPS_CHK 3 /*!< basic ops count for ecp_check_pubkey() */ +#define MBEDTLS_ECP_OPS_DBL 8 /*!< basic ops count for ecp_double_jac() */ +#define MBEDTLS_ECP_OPS_ADD 11 /*!< basic ops count for see ecp_add_mixed() */ +#define MBEDTLS_ECP_OPS_INV 120 /*!< empirical equivalent for mpi_mod_inv() */ + +/** + * \brief Internal; for restartable functions in other modules. + * Check and update basic ops budget. + * + * \param grp Group structure + * \param rs_ctx Restart context + * \param ops Number of basic ops to do + * + * \return \c 0 if doing \p ops basic ops is still allowed, + * \return #MBEDTLS_ERR_ECP_IN_PROGRESS otherwise. + */ +int mbedtls_ecp_check_budget( const mbedtls_ecp_group *grp, + mbedtls_ecp_restart_ctx *rs_ctx, + unsigned ops ); + +/* Utility macro for checking and updating ops budget */ +#define MBEDTLS_ECP_BUDGET( ops ) \ + MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, rs_ctx, \ + (unsigned) (ops) ) ); + +#else /* MBEDTLS_ECP_RESTARTABLE */ + +#define MBEDTLS_ECP_BUDGET( ops ) /* no-op; for compatibility */ + +/* We want to declare restartable versions of existing functions anyway */ +typedef void mbedtls_ecp_restart_ctx; + +#endif /* MBEDTLS_ECP_RESTARTABLE */ + +#if defined(MBEDTLS_ECP_RESTARTABLE) +/* + * Maximum number of "basic operations" to be done in a row. + * + * Default value 0 means that ECC operations will not yield. + * Note that regardless of the value of ecp_max_ops, always at + * least one step is performed before yielding. + * + * Setting ecp_max_ops=1 can be suitable for testing purposes + * as it will interrupt computation at all possible points. + */ +static unsigned ecp_max_ops = 0; + +/* + * Set ecp_max_ops + */ +void mbedtls_ecp_set_max_ops( unsigned max_ops ) +{ + ecp_max_ops = max_ops; +} + +/* + * Check if restart is enabled + */ +int mbedtls_ecp_restart_is_enabled( void ) +{ + return( ecp_max_ops != 0 ); +} + +/* + * Restart sub-context for ecp_mul_comb() + */ +struct mbedtls_ecp_restart_mul +{ + mbedtls_ecp_point R; /* current intermediate result */ + size_t i; /* current index in various loops, 0 outside */ + mbedtls_ecp_point *T; /* table for precomputed points */ + unsigned char T_size; /* number of points in table T */ + enum { /* what were we doing last time we returned? */ + ecp_rsm_init = 0, /* nothing so far, dummy initial state */ + ecp_rsm_pre_dbl, /* precompute 2^n multiples */ + ecp_rsm_pre_norm_dbl, /* normalize precomputed 2^n multiples */ + ecp_rsm_pre_add, /* precompute remaining points by adding */ + ecp_rsm_pre_norm_add, /* normalize all precomputed points */ + ecp_rsm_comb_core, /* ecp_mul_comb_core() */ + ecp_rsm_final_norm, /* do the final normalization */ + } state; +}; + +/* + * Init restart_mul sub-context + */ +static void ecp_restart_rsm_init( mbedtls_ecp_restart_mul_ctx *ctx ) +{ + mbedtls_ecp_point_init( &ctx->R ); + ctx->i = 0; + ctx->T = NULL; + ctx->T_size = 0; + ctx->state = ecp_rsm_init; +} + +/* + * Free the components of a restart_mul sub-context + */ +static void ecp_restart_rsm_free( mbedtls_ecp_restart_mul_ctx *ctx ) +{ + unsigned char i; + + if( ctx == NULL ) + return; + + mbedtls_ecp_point_free( &ctx->R ); + + if( ctx->T != NULL ) + { + for( i = 0; i < ctx->T_size; i++ ) + mbedtls_ecp_point_free( ctx->T + i ); + mbedtls_free( ctx->T ); + } + + ecp_restart_rsm_init( ctx ); +} + +/* + * Restart context for ecp_muladd() + */ +struct mbedtls_ecp_restart_muladd +{ + mbedtls_ecp_point mP; /* mP value */ + mbedtls_ecp_point R; /* R intermediate result */ + enum { /* what should we do next? */ + ecp_rsma_mul1 = 0, /* first multiplication */ + ecp_rsma_mul2, /* second multiplication */ + ecp_rsma_add, /* addition */ + ecp_rsma_norm, /* normalization */ + } state; +}; + +/* + * Init restart_muladd sub-context + */ +static void ecp_restart_ma_init( mbedtls_ecp_restart_muladd_ctx *ctx ) +{ + mbedtls_ecp_point_init( &ctx->mP ); + mbedtls_ecp_point_init( &ctx->R ); + ctx->state = ecp_rsma_mul1; +} + +/* + * Free the components of a restart_muladd sub-context + */ +static void ecp_restart_ma_free( mbedtls_ecp_restart_muladd_ctx *ctx ) +{ + if( ctx == NULL ) + return; + + mbedtls_ecp_point_free( &ctx->mP ); + mbedtls_ecp_point_free( &ctx->R ); + + ecp_restart_ma_init( ctx ); +} + +/* + * Initialize a restart context + */ +void mbedtls_ecp_restart_init( mbedtls_ecp_restart_ctx *ctx ) +{ + ctx->ops_done = 0; + ctx->depth = 0; + ctx->rsm = NULL; + ctx->ma = NULL; +} + +/* + * Free the components of a restart context + */ +void mbedtls_ecp_restart_free( mbedtls_ecp_restart_ctx *ctx ) +{ + if( ctx == NULL ) + return; + + ecp_restart_rsm_free( ctx->rsm ); + mbedtls_free( ctx->rsm ); + + ecp_restart_ma_free( ctx->ma ); + mbedtls_free( ctx->ma ); + + mbedtls_ecp_restart_init( ctx ); +} + +/* + * Check if we can do the next step + */ +int mbedtls_ecp_check_budget( const mbedtls_ecp_group *grp, + mbedtls_ecp_restart_ctx *rs_ctx, + unsigned ops ) +{ + if( rs_ctx != NULL && ecp_max_ops != 0 ) + { + /* scale depending on curve size: the chosen reference is 256-bit, + * and multiplication is quadratic. Round to the closest integer. */ + if( grp->pbits >= 512 ) + ops *= 4; + else if( grp->pbits >= 384 ) + ops *= 2; + + /* Avoid infinite loops: always allow first step. + * Because of that, however, it's not generally true + * that ops_done <= ecp_max_ops, so the check + * ops_done > ecp_max_ops below is mandatory. */ + if( ( rs_ctx->ops_done != 0 ) && + ( rs_ctx->ops_done > ecp_max_ops || + ops > ecp_max_ops - rs_ctx->ops_done ) ) + { + return( MBEDTLS_ERR_ECP_IN_PROGRESS ); + } + + /* update running count */ + rs_ctx->ops_done += ops; + } + + return( 0 ); +} + +/* Call this when entering a function that needs its own sub-context */ +#define ECP_RS_ENTER( SUB ) do { \ + /* reset ops count for this call if top-level */ \ + if( rs_ctx != NULL && rs_ctx->depth++ == 0 ) \ + rs_ctx->ops_done = 0; \ + \ + /* set up our own sub-context if needed */ \ + if( mbedtls_ecp_restart_is_enabled() && \ + rs_ctx != NULL && rs_ctx->SUB == NULL ) \ + { \ + rs_ctx->SUB = mbedtls_calloc( 1, sizeof( *rs_ctx->SUB ) ); \ + if( rs_ctx->SUB == NULL ) \ + return( MBEDTLS_ERR_ECP_ALLOC_FAILED ); \ + \ + ecp_restart_## SUB ##_init( rs_ctx->SUB ); \ + } \ +} while( 0 ) + +/* Call this when leaving a function that needs its own sub-context */ +#define ECP_RS_LEAVE( SUB ) do { \ + /* clear our sub-context when not in progress (done or error) */ \ + if( rs_ctx != NULL && rs_ctx->SUB != NULL && \ + ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) \ + { \ + ecp_restart_## SUB ##_free( rs_ctx->SUB ); \ + mbedtls_free( rs_ctx->SUB ); \ + rs_ctx->SUB = NULL; \ + } \ + \ + if( rs_ctx != NULL ) \ + rs_ctx->depth--; \ +} while( 0 ) + +#else /* MBEDTLS_ECP_RESTARTABLE */ + +#define ECP_RS_ENTER( sub ) (void) rs_ctx; +#define ECP_RS_LEAVE( sub ) (void) rs_ctx; + +#endif /* MBEDTLS_ECP_RESTARTABLE */ + #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \ @@ -228,6 +495,42 @@ static const mbedtls_ecp_curve_info ecp_supported_curves[] = static mbedtls_ecp_group_id ecp_supported_grp_id[ECP_NB_CURVES]; +#include "cc310_mbedtls.h" +#include "crys_rnd.h" +#include "crys_ecpki_kg.h" +#include "crys_ecpki_domain.h" +#include "ssi_bitops.h" + +extern CRYSError_t PkaEcWrstScalarMult(const CRYS_ECPKI_Domain_t *pDomain, + const uint32_t *scalar, + uint32_t scalSizeInWords, + uint32_t *inPointX, + uint32_t *inPointY, + uint32_t *outPointX, + uint32_t *outPointY, + uint32_t *tmpBuff); + +extern CRYS_RND_State_t * pRndState; + +#define CC_CALLOC_CHECK(ptr, size) \ +do \ +{ \ + if (( ptr = mbedtls_calloc( 1, size ) ) == NULL ) \ + { \ + ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; \ + goto cleanup; \ + } \ +} while (0) + +#define CC_CHECK_FREE(ptr) \ +do \ +{ \ + if (ptr != NULL) \ + { \ + mbedtls_free( ptr ); \ + } \ +} while (0) + static void endianess_swap( uint32_t * buf, uint32_t len ) { for ( uint32_t i = 0; i < len / 2; i++ ) @@ -297,6 +600,156 @@ static CRYS_ECPKI_DomainID_t mbedtls_to_cryptocell_group_id( mbedtls_ecp_group_i return cc_id; } +#if defined(ECP_SHORTWEIERSTRASS) + +/* + * Multiplication with CryptoCell hardware acceleration, + * for curves in short Weierstrass form + */ +static int ecp_mul_ws_cryptocell( CRYS_ECPKI_DomainID_t grp_id, mbedtls_ecp_point *R, + const mbedtls_mpi *m, const mbedtls_ecp_point *P ) +{ + int ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; + + const CRYS_ECPKI_Domain_t * pDomain = CRYS_ECPKI_GetEcDomain( grp_id ); + + uint32_t orderSizeInWords = ( pDomain->ordSizeInBits + ( 8 * sizeof( uint32_t ) ) - 1 ) / + ( 8 * sizeof( uint32_t ) ); + + uint32_t *scalar = NULL; + uint32_t *inPointX = NULL; + uint32_t *inPointY = NULL; + uint32_t *outPointX = NULL; + uint32_t *outPointY = NULL; + uint32_t *tmpBuff = NULL; + + CC_CALLOC_CHECK(scalar, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); + CC_CALLOC_CHECK(inPointX, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); + CC_CALLOC_CHECK(inPointY, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); + CC_CALLOC_CHECK(outPointX, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); + CC_CALLOC_CHECK(outPointY, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); + CC_CALLOC_CHECK(tmpBuff, sizeof(uint32_t) * CRYS_PKA_ECPKI_SCALAR_MUL_BUFF_MAX_LENGTH_IN_WORDS); + + // Convert input from mbedTLS to CryptoCell convention. + mbedtls_mpi_write_binary( m, ( uint8_t *)scalar, sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_write_binary( &P->X, ( uint8_t * )inPointX, sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_write_binary( &P->Y, ( uint8_t * )inPointY, sizeof( uint32_t ) * orderSizeInWords ); + endianess_swap( scalar, orderSizeInWords ); + endianess_swap( inPointX, orderSizeInWords ); + endianess_swap( inPointY, orderSizeInWords ); + + // Multipy point by scalar. + CRYSError_t error; + CC310_OPERATION(PkaEcWrstScalarMult( pDomain, scalar, orderSizeInWords, + inPointX, inPointY, outPointX, outPointY, tmpBuff ), + error); + + if ( error == CRYS_OK ) + { + // Convert output from CryptoCell to mbedTLS convention. + mbedtls_mpi_read_binary( &R->X, ( const uint8_t * )outPointX, + sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_read_binary( &R->Y, ( const uint8_t * )outPointY, + sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_lset( &R->Z, 1 ); + endianess_swap( R->X.p, orderSizeInWords ); + endianess_swap( R->Y.p, orderSizeInWords ); + + ret = 0; + } + else + { + ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + +cleanup: + + CC_CHECK_FREE(scalar); + CC_CHECK_FREE(inPointX); + CC_CHECK_FREE(inPointY); + CC_CHECK_FREE(outPointX); + CC_CHECK_FREE(outPointY); + CC_CHECK_FREE(tmpBuff); + + return ret; +} + +#endif /* ECP_SHORTWEIERSTRASS */ + +/* + * Generate key pair with CryptoCell hardware acceleration. + */ +static int ecp_gen_keypair_cryptocell( CRYS_ECPKI_DomainID_t grp_id, const mbedtls_ecp_point *G, + mbedtls_mpi *d, mbedtls_ecp_point *Q ) +{ + int ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; + uint32_t orderSizeInWords; + + CRYS_ECPKI_UserPrivKey_t *UserPrivKey = NULL; + CRYS_ECPKI_UserPublKey_t *UserPublKey = NULL; + CRYS_ECPKI_KG_TempData_t *TempECCKGBuff = NULL; + CRYS_ECPKI_KG_FipsContext_t *FipsBuff = NULL; + CRYS_ECPKI_Domain_t *domain = NULL; + + CC_CALLOC_CHECK(UserPrivKey, sizeof( *UserPrivKey )); + CC_CALLOC_CHECK(UserPublKey, sizeof( *UserPublKey )); + CC_CALLOC_CHECK(TempECCKGBuff, sizeof( *TempECCKGBuff )); + CC_CALLOC_CHECK(FipsBuff, sizeof( *FipsBuff )); + CC_CALLOC_CHECK(domain, sizeof( *domain )); + + *domain = *CRYS_ECPKI_GetEcDomain( grp_id ); + + orderSizeInWords = ( domain->ordSizeInBits + ( 8 * sizeof( uint32_t ) ) - 1 ) / + ( 8 * sizeof( uint32_t ) ); + + // Copy generator point from mbedTLS to CryptoCell convention. + mbedtls_mpi_write_binary( &G->X, ( uint8_t * )domain->ecGx, sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_write_binary( &G->Y, ( uint8_t * )domain->ecGy, sizeof( uint32_t ) * orderSizeInWords ); + endianess_swap(domain->ecGx, orderSizeInWords); + endianess_swap(domain->ecGy, orderSizeInWords); + + // Generate keys with CryptoCell. + CRYSError_t error; + CC310_OPERATION(CRYS_ECPKI_GenKeyPair( pRndState, CRYS_RND_GenerateVector, domain, + UserPrivKey, UserPublKey, TempECCKGBuff, FipsBuff ), + error); + + if (error == CRYS_OK) + { + CRYS_ECPKI_PrivKey_t * privateKey = ( CRYS_ECPKI_PrivKey_t * )UserPrivKey->PrivKeyDbBuff; + CRYS_ECPKI_PublKey_t * publicKey = ( CRYS_ECPKI_PublKey_t * )UserPublKey->PublKeyDbBuff; + + // Convert keys from CryptoCell to mbedTLS convention. + mbedtls_mpi_read_binary( d, ( const uint8_t * )privateKey->PrivKey, + sizeof( uint32_t ) * orderSizeInWords ); + endianess_swap(d->p, orderSizeInWords); + + mbedtls_mpi_read_binary( &Q->X, ( const uint8_t * )publicKey->x, + sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_read_binary( &Q->Y, ( const uint8_t * )publicKey->y, + sizeof( uint32_t ) * orderSizeInWords ); + mbedtls_mpi_lset( &Q->Z, 1 ); + endianess_swap( Q->X.p, orderSizeInWords ); + endianess_swap( Q->Y.p, orderSizeInWords ); + + ret = 0; + } + else + { + ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + +cleanup: + + CC_CHECK_FREE(UserPrivKey); + CC_CHECK_FREE(UserPublKey); + CC_CHECK_FREE(TempECCKGBuff); + CC_CHECK_FREE(FipsBuff); + CC_CHECK_FREE(domain); + + return ret; +} + /* * List of supported curves and associated info */ @@ -420,7 +873,21 @@ void mbedtls_ecp_group_init( mbedtls_ecp_group *grp ) if( grp == NULL ) return; - memset( grp, 0, sizeof( mbedtls_ecp_group ) ); + grp->id = MBEDTLS_ECP_DP_NONE; + mbedtls_mpi_init( &grp->P ); + mbedtls_mpi_init( &grp->A ); + mbedtls_mpi_init( &grp->B ); + mbedtls_ecp_point_init( &grp->G ); + mbedtls_mpi_init( &grp->N ); + grp->pbits = 0; + grp->nbits = 0; + grp->h = 0; + grp->modp = NULL; + grp->t_pre = NULL; + grp->t_post = NULL; + grp->t_data = NULL; + grp->T = NULL; + grp->T_size = 0; } /* @@ -475,7 +942,7 @@ void mbedtls_ecp_group_free( mbedtls_ecp_group *grp ) mbedtls_free( grp->T ); } - mbedtls_zeroize( grp, sizeof( mbedtls_ecp_group ) ); + mbedtls_platform_zeroize( grp, sizeof( mbedtls_ecp_group ) ); } /* @@ -883,11 +1350,10 @@ static int ecp_normalize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *p return( 0 ); #if defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_normalize_jac( grp, pt ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_normalize_jac( grp, pt ) ); #endif /* MBEDTLS_ECP_NORMALIZE_JAC_ALT */ + mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi ); /* @@ -927,32 +1393,33 @@ cleanup: * Cost: 1N(t) := 1I + (6t - 3)M + 1S */ static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp, - mbedtls_ecp_point *T[], size_t t_len ) + mbedtls_ecp_point *T[], size_t T_size ) { int ret; size_t i; mbedtls_mpi *c, u, Zi, ZZi; - if( t_len < 2 ) + if( T_size < 2 ) return( ecp_normalize_jac( grp, *T ) ); #if defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_normalize_jac_many(grp, T, t_len); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_normalize_jac_many( grp, T, T_size ) ); #endif - if( ( c = mbedtls_calloc( t_len, sizeof( mbedtls_mpi ) ) ) == NULL ) + if( ( c = mbedtls_calloc( T_size, sizeof( mbedtls_mpi ) ) ) == NULL ) return( MBEDTLS_ERR_ECP_ALLOC_FAILED ); + for( i = 0; i < T_size; i++ ) + mbedtls_mpi_init( &c[i] ); + mbedtls_mpi_init( &u ); mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi ); /* * c[i] = Z_0 * ... * Z_i */ MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &c[0], &T[0]->Z ) ); - for( i = 1; i < t_len; i++ ) + for( i = 1; i < T_size; i++ ) { MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &c[i], &c[i-1], &T[i]->Z ) ); MOD_MUL( c[i] ); @@ -961,9 +1428,9 @@ static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp, /* * u = 1 / (Z_0 * ... * Z_n) mod P */ - MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &u, &c[t_len-1], &grp->P ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &u, &c[T_size-1], &grp->P ) ); - for( i = t_len - 1; ; i-- ) + for( i = T_size - 1; ; i-- ) { /* * Zi = 1 / Z_i mod p @@ -1003,7 +1470,7 @@ static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp, cleanup: mbedtls_mpi_free( &u ); mbedtls_mpi_free( &Zi ); mbedtls_mpi_free( &ZZi ); - for( i = 0; i < t_len; i++ ) + for( i = 0; i < T_size; i++ ) mbedtls_mpi_free( &c[i] ); mbedtls_free( c ); @@ -1060,10 +1527,8 @@ static int ecp_double_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, #endif #if defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_double_jac( grp, R, P ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_double_jac( grp, R, P ) ); #endif /* MBEDTLS_ECP_DOUBLE_JAC_ALT */ mbedtls_mpi_init( &M ); mbedtls_mpi_init( &S ); mbedtls_mpi_init( &T ); mbedtls_mpi_init( &U ); @@ -1158,10 +1623,8 @@ static int ecp_add_mixed( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, #endif #if defined(MBEDTLS_ECP_ADD_MIXED_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_add_mixed( grp, R, P, Q ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_add_mixed( grp, R, P, Q ) ); #endif /* MBEDTLS_ECP_ADD_MIXED_ALT */ /* @@ -1245,10 +1708,8 @@ static int ecp_randomize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *p int count = 0; #if defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_randomize_jac( grp, pt, f_rng, p_rng ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_randomize_jac( grp, pt, f_rng, p_rng ) ); #endif /* MBEDTLS_ECP_RANDOMIZE_JAC_ALT */ p_size = ( grp->pbits + 7 ) / 8; @@ -1304,11 +1765,38 @@ cleanup: * modified version that provides resistance to SPA by avoiding zero * digits in the representation as in [3]. We modify the method further by * requiring that all K_i be odd, which has the small cost that our - * representation uses one more K_i, due to carries. + * representation uses one more K_i, due to carries, but saves on the size of + * the precomputed table. * - * Also, for the sake of compactness, only the seven low-order bits of x[i] - * are used to represent K_i, and the msb of x[i] encodes the the sign (s_i in - * the paper): it is set if and only if if s_i == -1; + * Summary of the comb method and its modifications: + * + * - The goal is to compute m*P for some w*d-bit integer m. + * + * - The basic comb method splits m into the w-bit integers + * x[0] .. x[d-1] where x[i] consists of the bits in m whose + * index has residue i modulo d, and computes m * P as + * S[x[0]] + 2 * S[x[1]] + .. + 2^(d-1) S[x[d-1]], where + * S[i_{w-1} .. i_0] := i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + i_0 P. + * + * - If it happens that, say, x[i+1]=0 (=> S[x[i+1]]=0), one can replace the sum by + * .. + 2^{i-1} S[x[i-1]] - 2^i S[x[i]] + 2^{i+1} S[x[i]] + 2^{i+2} S[x[i+2]] .., + * thereby successively converting it into a form where all summands + * are nonzero, at the cost of negative summands. This is the basic idea of [3]. + * + * - More generally, even if x[i+1] != 0, we can first transform the sum as + * .. - 2^i S[x[i]] + 2^{i+1} ( S[x[i]] + S[x[i+1]] ) + 2^{i+2} S[x[i+2]] .., + * and then replace S[x[i]] + S[x[i+1]] = S[x[i] ^ x[i+1]] + 2 S[x[i] & x[i+1]]. + * Performing and iterating this procedure for those x[i] that are even + * (keeping track of carry), we can transform the original sum into one of the form + * S[x'[0]] +- 2 S[x'[1]] +- .. +- 2^{d-1} S[x'[d-1]] + 2^d S[x'[d]] + * with all x'[i] odd. It is therefore only necessary to know S at odd indices, + * which is why we are only computing half of it in the first place in + * ecp_precompute_comb and accessing it with index abs(i) / 2 in ecp_select_comb. + * + * - For the sake of compactness, only the seven low-order bits of x[i] + * are used to represent its absolute value (K_i in the paper), and the msb + * of x[i] encodes the sign (s_i in the paper): it is set if and only if + * if s_i == -1; * * Calling conventions: * - x is an array of size d + 1 @@ -1317,8 +1805,8 @@ cleanup: * - m is the MPI, expected to be odd and such that bitlength(m) <= w * d * (the result will be incorrect if these assumptions are not satisfied) */ -static void ecp_comb_fixed( unsigned char x[], size_t d, - unsigned char w, const mbedtls_mpi *m ) +static void ecp_comb_recode_core( unsigned char x[], size_t d, + unsigned char w, const mbedtls_mpi *m ) { size_t i, j; unsigned char c, cc, adjust; @@ -1348,70 +1836,178 @@ static void ecp_comb_fixed( unsigned char x[], size_t d, } /* - * Precompute points for the comb method + * Precompute points for the adapted comb method * - * If i = i_{w-1} ... i_1 is the binary representation of i, then - * T[i] = i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + P + * Assumption: T must be able to hold 2^{w - 1} elements. * - * T must be able to hold 2^{w - 1} elements + * Operation: If i = i_{w-1} ... i_1 is the binary representation of i, + * sets T[i] = i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + P. * * Cost: d(w-1) D + (2^{w-1} - 1) A + 1 N(w-1) + 1 N(2^{w-1} - 1) + * + * Note: Even comb values (those where P would be omitted from the + * sum defining T[i] above) are not needed in our adaption + * the comb method. See ecp_comb_recode_core(). + * + * This function currently works in four steps: + * (1) [dbl] Computation of intermediate T[i] for 2-power values of i + * (2) [norm_dbl] Normalization of coordinates of these T[i] + * (3) [add] Computation of all T[i] + * (4) [norm_add] Normalization of all T[i] + * + * Step 1 can be interrupted but not the others; together with the final + * coordinate normalization they are the largest steps done at once, depending + * on the window size. Here are operation counts for P-256: + * + * step (2) (3) (4) + * w = 5 142 165 208 + * w = 4 136 77 160 + * w = 3 130 33 136 + * w = 2 124 11 124 + * + * So if ECC operations are blocking for too long even with a low max_ops + * value, it's useful to set MBEDTLS_ECP_WINDOW_SIZE to a lower value in order + * to minimize maximum blocking time. */ static int ecp_precompute_comb( const mbedtls_ecp_group *grp, mbedtls_ecp_point T[], const mbedtls_ecp_point *P, - unsigned char w, size_t d ) + unsigned char w, size_t d, + mbedtls_ecp_restart_ctx *rs_ctx ) { int ret; - unsigned char i, k; - size_t j; + unsigned char i; + size_t j = 0; + const unsigned char T_size = 1U << ( w - 1 ); mbedtls_ecp_point *cur, *TT[COMB_MAX_PRE - 1]; +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + { + if( rs_ctx->rsm->state == ecp_rsm_pre_dbl ) + goto dbl; + if( rs_ctx->rsm->state == ecp_rsm_pre_norm_dbl ) + goto norm_dbl; + if( rs_ctx->rsm->state == ecp_rsm_pre_add ) + goto add; + if( rs_ctx->rsm->state == ecp_rsm_pre_norm_add ) + goto norm_add; + } +#else + (void) rs_ctx; +#endif + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + { + rs_ctx->rsm->state = ecp_rsm_pre_dbl; + + /* initial state for the loop */ + rs_ctx->rsm->i = 0; + } + +dbl: +#endif /* * Set T[0] = P and * T[2^{l-1}] = 2^{dl} P for l = 1 .. w-1 (this is not the final value) */ MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &T[0], P ) ); - k = 0; - for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 ) - { - cur = T + i; - MBEDTLS_MPI_CHK( mbedtls_ecp_copy( cur, T + ( i >> 1 ) ) ); - for( j = 0; j < d; j++ ) - MBEDTLS_MPI_CHK( ecp_double_jac( grp, cur, cur ) ); +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->i != 0 ) + j = rs_ctx->rsm->i; + else +#endif + j = 0; - TT[k++] = cur; + for( ; j < d * ( w - 1 ); j++ ) + { + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_DBL ); + + i = 1U << ( j / d ); + cur = T + i; + + if( j % d == 0 ) + MBEDTLS_MPI_CHK( mbedtls_ecp_copy( cur, T + ( i >> 1 ) ) ); + + MBEDTLS_MPI_CHK( ecp_double_jac( grp, cur, cur ) ); } - MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) ); +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + rs_ctx->rsm->state = ecp_rsm_pre_norm_dbl; +norm_dbl: +#endif + /* + * Normalize current elements in T. As T has holes, + * use an auxiliary array of pointers to elements in T. + */ + j = 0; + for( i = 1; i < T_size; i <<= 1 ) + TT[j++] = T + i; + + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV + 6 * j - 2 ); + + MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, j ) ); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + rs_ctx->rsm->state = ecp_rsm_pre_add; + +add: +#endif /* * Compute the remaining ones using the minimal number of additions * Be careful to update T[2^l] only after using it! */ - k = 0; - for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 ) + MBEDTLS_ECP_BUDGET( ( T_size - 1 ) * MBEDTLS_ECP_OPS_ADD ); + + for( i = 1; i < T_size; i <<= 1 ) { j = i; while( j-- ) - { MBEDTLS_MPI_CHK( ecp_add_mixed( grp, &T[i + j], &T[j], &T[i] ) ); - TT[k++] = &T[i + j]; - } } - MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) ); +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + rs_ctx->rsm->state = ecp_rsm_pre_norm_add; + +norm_add: +#endif + /* + * Normalize final elements in T. Even though there are no holes now, we + * still need the auxiliary array for homogeneity with the previous + * call. Also, skip T[0] which is already normalised, being a copy of P. + */ + for( j = 0; j + 1 < T_size; j++ ) + TT[j] = T + j + 1; + + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV + 6 * j - 2 ); + + MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, j ) ); cleanup: +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL && + ret == MBEDTLS_ERR_ECP_IN_PROGRESS ) + { + if( rs_ctx->rsm->state == ecp_rsm_pre_dbl ) + rs_ctx->rsm->i = j; + } +#endif return( ret ); } /* * Select precomputed point: R = sign(i) * T[ abs(i) / 2 ] + * + * See ecp_comb_recode_core() for background */ static int ecp_select_comb( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, - const mbedtls_ecp_point T[], unsigned char t_len, + const mbedtls_ecp_point T[], unsigned char T_size, unsigned char i ) { int ret; @@ -1421,7 +2017,7 @@ static int ecp_select_comb( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, ii = ( i & 0x7Fu ) >> 1; /* Read the whole table to thwart cache-based timing attacks */ - for( j = 0; j < t_len; j++ ) + for( j = 0; j < T_size; j++ ) { MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->X, &T[j].X, j == ii ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->Y, &T[j].Y, j == ii ) ); @@ -1441,10 +2037,11 @@ cleanup: * Cost: d A + d D + 1 R */ static int ecp_mul_comb_core( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, - const mbedtls_ecp_point T[], unsigned char t_len, + const mbedtls_ecp_point T[], unsigned char T_size, const unsigned char x[], size_t 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 Txi; @@ -1452,17 +2049,42 @@ static int ecp_mul_comb_core( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R mbedtls_ecp_point_init( &Txi ); - /* Start with a non-zero point and randomize its coordinates */ - i = d; - MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, t_len, x[i] ) ); - MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) ); - if( f_rng != 0 ) - MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) ); +#if !defined(MBEDTLS_ECP_RESTARTABLE) + (void) rs_ctx; +#endif - while( i-- != 0 ) +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL && + rs_ctx->rsm->state != ecp_rsm_comb_core ) { + rs_ctx->rsm->i = 0; + rs_ctx->rsm->state = ecp_rsm_comb_core; + } + + /* new 'if' instead of nested for the sake of the 'else' branch */ + if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->i != 0 ) + { + /* restore current index (R already pointing to rs_ctx->rsm->R) */ + i = rs_ctx->rsm->i; + } + else +#endif + { + /* Start with a non-zero point and randomize its coordinates */ + i = d; + MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, T_size, x[i] ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) ); + if( f_rng != 0 ) + MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) ); + } + + while( i != 0 ) + { + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_DBL + MBEDTLS_ECP_OPS_ADD ); + --i; + MBEDTLS_MPI_CHK( ecp_double_jac( grp, R, R ) ); - MBEDTLS_MPI_CHK( ecp_select_comb( grp, &Txi, T, t_len, x[i] ) ); + MBEDTLS_MPI_CHK( ecp_select_comb( grp, &Txi, T, T_size, x[i] ) ); MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, R, &Txi ) ); } @@ -1470,32 +2092,130 @@ cleanup: mbedtls_ecp_point_free( &Txi ); +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL && + ret == MBEDTLS_ERR_ECP_IN_PROGRESS ) + { + rs_ctx->rsm->i = i; + /* no need to save R, already pointing to rs_ctx->rsm->R */ + } +#endif + return( ret ); } /* - * Multiplication using the comb method, - * for curves in short Weierstrass form + * Recode the scalar to get constant-time comb multiplication + * + * As the actual scalar recoding needs an odd scalar as a starting point, + * this wrapper ensures that by replacing m by N - m if necessary, and + * informs the caller that the result of multiplication will be negated. + * + * This works because we only support large prime order for Short Weierstrass + * curves, so N is always odd hence either m or N - m is. + * + * See ecp_comb_recode_core() for background. */ -static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, - const mbedtls_mpi *m, const mbedtls_ecp_point *P, - int (*f_rng)(void *, unsigned char *, size_t), - void *p_rng ) +static int ecp_comb_recode_scalar( const mbedtls_ecp_group *grp, + const mbedtls_mpi *m, + unsigned char k[COMB_MAX_D + 1], + size_t d, + unsigned char w, + unsigned char *parity_trick ) { int ret; - unsigned char w, m_is_odd, p_eq_g, pre_len, i; - size_t d; - unsigned char k[COMB_MAX_D + 1]; - mbedtls_ecp_point *T; mbedtls_mpi M, mm; mbedtls_mpi_init( &M ); mbedtls_mpi_init( &mm ); - /* we need N to be odd to trnaform m in an odd number, check now */ + /* N is always odd (see above), just make extra sure */ if( mbedtls_mpi_get_bit( &grp->N, 0 ) != 1 ) return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); + /* do we need the parity trick? */ + *parity_trick = ( mbedtls_mpi_get_bit( m, 0 ) == 0 ); + + /* execute parity fix in constant time */ + MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &M, m ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mm, &grp->N, m ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &M, &mm, *parity_trick ) ); + + /* actual scalar recoding */ + ecp_comb_recode_core( k, d, w, &M ); + +cleanup: + mbedtls_mpi_free( &mm ); + mbedtls_mpi_free( &M ); + + return( ret ); +} + +/* + * Perform comb multiplication (for short Weierstrass curves) + * once the auxiliary table has been pre-computed. + * + * Scalar recoding may use a parity trick that makes us compute -m * P, + * if that is the case we'll need to recover m * P at the end. + */ +static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp, + mbedtls_ecp_point *R, + const mbedtls_mpi *m, + const mbedtls_ecp_point *T, + unsigned char T_size, + unsigned char w, + size_t d, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecp_restart_ctx *rs_ctx ) +{ + int ret; + unsigned char parity_trick; + unsigned char k[COMB_MAX_D + 1]; + mbedtls_ecp_point *RR = R; + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + { + RR = &rs_ctx->rsm->R; + + if( rs_ctx->rsm->state == ecp_rsm_final_norm ) + goto final_norm; + } +#endif + + MBEDTLS_MPI_CHK( ecp_comb_recode_scalar( grp, m, k, d, w, + &parity_trick ) ); + MBEDTLS_MPI_CHK( ecp_mul_comb_core( grp, RR, T, T_size, k, d, + f_rng, p_rng, rs_ctx ) ); + MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, RR, parity_trick ) ); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + rs_ctx->rsm->state = ecp_rsm_final_norm; + +final_norm: +#endif + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV ); + MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) ); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL ) + MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, RR ) ); +#endif + +cleanup: + return( ret ); +} + +/* + * Pick window size based on curve size and whether we optimize for base point + */ +static unsigned char ecp_pick_window_size( const mbedtls_ecp_group *grp, + unsigned char p_eq_g ) +{ + unsigned char w; + /* * Minimize the number of multiplications, that is minimize * 10 * d * w + 18 * 2^(w-1) + 11 * d + 7 * w, with d = ceil( nbits / w ) @@ -1508,14 +2228,8 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, * Just adding one avoids upping the cost of the first mul too much, * and the memory cost too. */ -#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1 - p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 && - mbedtls_mpi_cmp_mpi( &P->X, &grp->G.X ) == 0 ); if( p_eq_g ) w++; -#else - p_eq_g = 0; -#endif /* * Make sure w is within bounds. @@ -1526,145 +2240,143 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, if( w >= grp->nbits ) w = 2; - /* Other sizes that depend on w */ - pre_len = 1U << ( w - 1 ); + return( w ); +} + +/* + * Multiplication using the comb method - for curves in short Weierstrass form + * + * This function is mainly responsible for administrative work: + * - managing the restart context if enabled + * - managing the table of precomputed points (passed between the below two + * functions): allocation, computation, ownership tranfer, freeing. + * + * It delegates the actual arithmetic work to: + * ecp_precompute_comb() and ecp_mul_comb_with_precomp() + * + * See comments on ecp_comb_recode_core() regarding the computation strategy. + */ +static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, + const mbedtls_mpi *m, const mbedtls_ecp_point *P, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecp_restart_ctx *rs_ctx ) +{ + int ret; + unsigned char w, p_eq_g, i; + size_t d; + unsigned char T_size, T_ok; + mbedtls_ecp_point *T; + + ECP_RS_ENTER( rsm ); + + /* Is P the base point ? */ +#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1 + p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 && + mbedtls_mpi_cmp_mpi( &P->X, &grp->G.X ) == 0 ); +#else + p_eq_g = 0; +#endif + + /* Pick window size and deduce related sizes */ + w = ecp_pick_window_size( grp, p_eq_g ); + T_size = 1U << ( w - 1 ); d = ( grp->nbits + w - 1 ) / w; - /* - * Prepare precomputed points: if P == G we want to - * use grp->T if already initialized, or initialize it. - */ - T = p_eq_g ? grp->T : NULL; - - if( T == NULL ) + /* Pre-computed table: do we have it already for the base point? */ + if( p_eq_g && grp->T != NULL ) { - T = mbedtls_calloc( pre_len, sizeof( mbedtls_ecp_point ) ); + /* second pointer to the same table, will be deleted on exit */ + T = grp->T; + T_ok = 1; + } + else +#if defined(MBEDTLS_ECP_RESTARTABLE) + /* Pre-computed table: do we have one in progress? complete? */ + if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->T != NULL ) + { + /* transfer ownership of T from rsm to local function */ + T = rs_ctx->rsm->T; + rs_ctx->rsm->T = NULL; + rs_ctx->rsm->T_size = 0; + + /* This effectively jumps to the call to mul_comb_after_precomp() */ + T_ok = rs_ctx->rsm->state >= ecp_rsm_comb_core; + } + else +#endif + /* Allocate table if we didn't have any */ + { + T = mbedtls_calloc( T_size, sizeof( mbedtls_ecp_point ) ); if( T == NULL ) { ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; goto cleanup; } - MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d ) ); + for( i = 0; i < T_size; i++ ) + mbedtls_ecp_point_init( &T[i] ); + + T_ok = 0; + } + + /* Compute table (or finish computing it) if not done already */ + if( !T_ok ) + { + MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d, rs_ctx ) ); if( p_eq_g ) { + /* almost transfer ownership of T to the group, but keep a copy of + * the pointer to use for calling the next function more easily */ grp->T = T; - grp->T_size = pre_len; + grp->T_size = T_size; } } - /* - * Make sure M is odd (M = m or M = N - m, since N is odd) - * using the fact that m * P = - (N - m) * P - */ - m_is_odd = ( mbedtls_mpi_get_bit( m, 0 ) == 1 ); - MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &M, m ) ); - MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mm, &grp->N, m ) ); - MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &M, &mm, ! m_is_odd ) ); - - /* - * Go for comb multiplication, R = M * P - */ - ecp_comb_fixed( k, d, w, &M ); - MBEDTLS_MPI_CHK( ecp_mul_comb_core( grp, R, T, pre_len, k, d, f_rng, p_rng ) ); - - /* - * Now get m * P from M * P and normalize it - */ - MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, R, ! m_is_odd ) ); - MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) ); + /* Actual comb multiplication using precomputed points */ + MBEDTLS_MPI_CHK( ecp_mul_comb_after_precomp( grp, R, m, + T, T_size, w, d, + f_rng, p_rng, rs_ctx ) ); cleanup: - if( T != NULL && ! p_eq_g ) + /* does T belong to the group? */ + if( T == grp->T ) + T = NULL; + + /* does T belong to the restart context? */ +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->rsm != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS && T != NULL ) { - for( i = 0; i < pre_len; i++ ) + /* transfer ownership of T from local function to rsm */ + rs_ctx->rsm->T_size = T_size; + rs_ctx->rsm->T = T; + T = NULL; + } +#endif + + /* did T belong to us? then let's destroy it! */ + if( T != NULL ) + { + for( i = 0; i < T_size; i++ ) mbedtls_ecp_point_free( &T[i] ); mbedtls_free( T ); } - mbedtls_mpi_free( &M ); - mbedtls_mpi_free( &mm ); - + /* don't free R while in progress in case R == P */ +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) +#endif + /* prevent caller from using invalid value */ if( ret != 0 ) mbedtls_ecp_point_free( R ); + ECP_RS_LEAVE( rsm ); + return( ret ); } -/* - * Multiplication with CryptoCell hardware acceleration, - * for curves in short Weierstrass form - */ -static int ecp_mul_ws_cryptocell( CRYS_ECPKI_DomainID_t grp_id, mbedtls_ecp_point *R, - const mbedtls_mpi *m, const mbedtls_ecp_point *P ) -{ - int ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; - - const CRYS_ECPKI_Domain_t * pDomain = CRYS_ECPKI_GetEcDomain( grp_id ); - - uint32_t orderSizeInWords = ( pDomain->ordSizeInBits + ( 8 * sizeof( uint32_t ) ) - 1 ) / - ( 8 * sizeof( uint32_t ) ); - - uint32_t *scalar = NULL; - uint32_t *inPointX = NULL; - uint32_t *inPointY = NULL; - uint32_t *outPointX = NULL; - uint32_t *outPointY = NULL; - uint32_t *tmpBuff = NULL; - - CC_CALLOC_CHECK(scalar, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); - CC_CALLOC_CHECK(inPointX, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); - CC_CALLOC_CHECK(inPointY, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); - CC_CALLOC_CHECK(outPointX, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); - CC_CALLOC_CHECK(outPointY, sizeof(uint32_t) * CRYS_ECPKI_MODUL_MAX_LENGTH_IN_WORDS); - CC_CALLOC_CHECK(tmpBuff, sizeof(uint32_t) * CRYS_PKA_ECPKI_SCALAR_MUL_BUFF_MAX_LENGTH_IN_WORDS); - - // Convert input from mbedTLS to CryptoCell convention. - mbedtls_mpi_write_binary( m, ( uint8_t *)scalar, sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_write_binary( &P->X, ( uint8_t * )inPointX, sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_write_binary( &P->Y, ( uint8_t * )inPointY, sizeof( uint32_t ) * orderSizeInWords ); - endianess_swap( scalar, orderSizeInWords ); - endianess_swap( inPointX, orderSizeInWords ); - endianess_swap( inPointY, orderSizeInWords ); - - // Multipy point by scalar. - CRYSError_t error; - CC310_OPERATION(PkaEcWrstScalarMult( pDomain, scalar, orderSizeInWords, - inPointX, inPointY, outPointX, outPointY, tmpBuff ), - error); - - if ( error == CRYS_OK ) - { - // Convert output from CryptoCell to mbedTLS convention. - mbedtls_mpi_read_binary( &R->X, ( const uint8_t * )outPointX, - sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_read_binary( &R->Y, ( const uint8_t * )outPointY, - sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_lset( &R->Z, 1 ); - endianess_swap( R->X.p, orderSizeInWords ); - endianess_swap( R->Y.p, orderSizeInWords ); - - ret = 0; - } - else - { - ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; - } - -cleanup: - - CC_CHECK_FREE(scalar); - CC_CHECK_FREE(inPointX); - CC_CHECK_FREE(inPointY); - CC_CHECK_FREE(outPointX); - CC_CHECK_FREE(outPointY); - CC_CHECK_FREE(tmpBuff); - - return ret; -} - #endif /* ECP_SHORTWEIERSTRASS */ #if defined(ECP_MONTGOMERY) @@ -1685,10 +2397,8 @@ static int ecp_normalize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P int ret; #if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_normalize_mxz( grp, P ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_normalize_mxz( grp, P ) ); #endif /* MBEDTLS_ECP_NORMALIZE_MXZ_ALT */ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &P->Z, &P->Z, &grp->P ) ); @@ -1716,10 +2426,8 @@ static int ecp_randomize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P int count = 0; #if defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_randomize_mxz( grp, P, f_rng, p_rng ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_randomize_mxz( grp, P, f_rng, p_rng ); #endif /* MBEDTLS_ECP_RANDOMIZE_MXZ_ALT */ p_size = ( grp->pbits + 7 ) / 8; @@ -1771,10 +2479,8 @@ static int ecp_double_add_mxz( const mbedtls_ecp_group *grp, mbedtls_mpi A, AA, B, BB, E, C, D, DA, CB; #if defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT) - if ( mbedtls_internal_ecp_grp_capable( grp ) ) - { - return mbedtls_internal_ecp_double_add_mxz( grp, R, S, P, Q, d ); - } + if( mbedtls_internal_ecp_grp_capable( grp ) ) + return( mbedtls_internal_ecp_double_add_mxz( grp, R, S, P, Q, d ) ); #endif /* MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT */ mbedtls_mpi_init( &A ); mbedtls_mpi_init( &AA ); mbedtls_mpi_init( &B ); @@ -1871,35 +2577,46 @@ cleanup: #endif /* ECP_MONTGOMERY */ /* - * Multiplication R = m * P + * Restartable multiplication R = m * P */ -int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, +int mbedtls_ecp_mul_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, - int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, + mbedtls_ecp_restart_ctx *rs_ctx ) { int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; #if defined(MBEDTLS_ECP_INTERNAL_ALT) char is_grp_capable = 0; #endif - /* Common sanity checks */ - if( mbedtls_mpi_cmp_int( &P->Z, 1 ) != 0 ) - return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); - - if( ( ret = mbedtls_ecp_check_privkey( grp, m ) ) != 0 || - ( ret = mbedtls_ecp_check_pubkey( grp, P ) ) != 0 ) - return( ret ); +#if defined(MBEDTLS_ECP_RESTARTABLE) + /* reset ops count for this call if top-level */ + if( rs_ctx != NULL && rs_ctx->depth++ == 0 ) + rs_ctx->ops_done = 0; +#endif #if defined(MBEDTLS_ECP_INTERNAL_ALT) - if ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) - { + if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) ) MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) ); +#endif /* MBEDTLS_ECP_INTERNAL_ALT */ + +#if defined(MBEDTLS_ECP_RESTARTABLE) + /* skip argument check when restarting */ + if( rs_ctx == NULL || rs_ctx->rsm == NULL ) +#endif + { + /* check_privkey is free */ + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_CHK ); + + /* Common sanity checks */ + MBEDTLS_MPI_CHK( mbedtls_ecp_check_privkey( grp, m ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, P ) ); } -#endif /* MBEDTLS_ECP_INTERNAL_ALT */ + ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; #if defined(ECP_MONTGOMERY) if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY ) - ret = ecp_mul_mxz( grp, R, m, P, f_rng, p_rng ); + MBEDTLS_MPI_CHK( ecp_mul_mxz( grp, R, m, P, f_rng, p_rng ) ); #endif #if defined(ECP_SHORTWEIERSTRASS) if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS ) @@ -1911,23 +2628,36 @@ int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, } else { - ret = ecp_mul_comb( grp, R, m, P, f_rng, p_rng ); + MBEDTLS_MPI_CHK( ecp_mul_comb( grp, R, m, P, f_rng, p_rng, rs_ctx ) ); } } - #endif -#if defined(MBEDTLS_ECP_INTERNAL_ALT) + cleanup: - if ( is_grp_capable ) - { +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + if( is_grp_capable ) mbedtls_internal_ecp_free( grp ); - } - #endif /* MBEDTLS_ECP_INTERNAL_ALT */ + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL ) + rs_ctx->depth--; +#endif + return( ret ); } +/* + * Multiplication R = m * P + */ +int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, + const mbedtls_mpi *m, const mbedtls_ecp_point *P, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) +{ + return( mbedtls_ecp_mul_restartable( grp, R, m, P, f_rng, p_rng, NULL ) ); +} + #if defined(ECP_SHORTWEIERSTRASS) /* * Check that an affine point is valid as a public key, @@ -1985,7 +2715,8 @@ cleanup: static int mbedtls_ecp_mul_shortcuts( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, - const mbedtls_ecp_point *P ) + const mbedtls_ecp_point *P, + mbedtls_ecp_restart_ctx *rs_ctx ) { int ret; @@ -2001,13 +2732,104 @@ static int mbedtls_ecp_mul_shortcuts( mbedtls_ecp_group *grp, } else { - MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, R, m, P, + NULL, NULL, rs_ctx ) ); } cleanup: return( ret ); } +/* + * Restartable linear combination + * NOT constant-time + */ +int mbedtls_ecp_muladd_restartable( + mbedtls_ecp_group *grp, mbedtls_ecp_point *R, + const mbedtls_mpi *m, const mbedtls_ecp_point *P, + const mbedtls_mpi *n, const mbedtls_ecp_point *Q, + mbedtls_ecp_restart_ctx *rs_ctx ) +{ + int ret; + mbedtls_ecp_point mP; + mbedtls_ecp_point *pmP = &mP; + mbedtls_ecp_point *pR = R; +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + char is_grp_capable = 0; +#endif + + if( ecp_get_type( grp ) != ECP_TYPE_SHORT_WEIERSTRASS ) + return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ); + + mbedtls_ecp_point_init( &mP ); + +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) ) + MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) ); +#endif /* MBEDTLS_ECP_INTERNAL_ALT */ + + ECP_RS_ENTER( ma ); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->ma != NULL ) + { + /* redirect intermediate results to restart context */ + pmP = &rs_ctx->ma->mP; + pR = &rs_ctx->ma->R; + + /* jump to next operation */ + if( rs_ctx->ma->state == ecp_rsma_mul2 ) + goto mul2; + if( rs_ctx->ma->state == ecp_rsma_add ) + goto add; + if( rs_ctx->ma->state == ecp_rsma_norm ) + goto norm; + } +#endif /* MBEDTLS_ECP_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 = 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 = ecp_rsma_add; + +add: +#endif + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_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 = ecp_rsma_norm; + +norm: +#endif + MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV ); + MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, pR ) ); + +#if defined(MBEDTLS_ECP_RESTARTABLE) + if( rs_ctx != NULL && rs_ctx->ma != NULL ) + MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, pR ) ); +#endif + +cleanup: +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + if( is_grp_capable ) + mbedtls_internal_ecp_free( grp ); +#endif /* MBEDTLS_ECP_INTERNAL_ALT */ + + mbedtls_ecp_point_free( &mP ); + + ECP_RS_LEAVE( ma ); + + return( ret ); +} + /* * Linear combination * NOT constant-time @@ -2016,45 +2838,9 @@ int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, const mbedtls_mpi *n, const mbedtls_ecp_point *Q ) { - int ret; - mbedtls_ecp_point mP; -#if defined(MBEDTLS_ECP_INTERNAL_ALT) - char is_grp_capable = 0; -#endif - - if( ecp_get_type( grp ) != ECP_TYPE_SHORT_WEIERSTRASS ) - return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ); - - mbedtls_ecp_point_init( &mP ); - - MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, &mP, m, P ) ); - MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, R, n, Q ) ); - -#if defined(MBEDTLS_ECP_INTERNAL_ALT) - if ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) - { - MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) ); - } - -#endif /* MBEDTLS_ECP_INTERNAL_ALT */ - MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, &mP, R ) ); - MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) ); - -cleanup: - -#if defined(MBEDTLS_ECP_INTERNAL_ALT) - if ( is_grp_capable ) - { - mbedtls_internal_ecp_free( grp ); - } - -#endif /* MBEDTLS_ECP_INTERNAL_ALT */ - mbedtls_ecp_point_free( &mP ); - - return( ret ); + return( mbedtls_ecp_muladd_restartable( grp, R, m, P, n, Q, NULL ) ); } - #if defined(ECP_MONTGOMERY) /* * Check validity of a public key for Montgomery curves with x-only schemes @@ -2104,7 +2890,6 @@ int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi * mbedtls_mpi_get_bit( d, 1 ) != 0 || mbedtls_mpi_bitlen( d ) - 1 != grp->nbits ) /* mbedtls_mpi_bitlen is one-based! */ return( MBEDTLS_ERR_ECP_INVALID_KEY ); - else /* see [Curve25519] page 5 */ if( grp->nbits == 254 && mbedtls_mpi_get_bit( d, 2 ) != 0 ) @@ -2129,89 +2914,14 @@ int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi * } /* - * Generate key pair with CryptoCell hardware acceleration. + * Generate a private key */ -static int ecp_gen_keypair_cryptocell( CRYS_ECPKI_DomainID_t grp_id, const mbedtls_ecp_point *G, - mbedtls_mpi *d, mbedtls_ecp_point *Q ) -{ - int ret = MBEDTLS_ERR_ECP_ALLOC_FAILED; - uint32_t orderSizeInWords; - - CRYS_ECPKI_UserPrivKey_t *UserPrivKey = NULL; - CRYS_ECPKI_UserPublKey_t *UserPublKey = NULL; - CRYS_ECPKI_KG_TempData_t *TempECCKGBuff = NULL; - CRYS_ECPKI_KG_FipsContext_t *FipsBuff = NULL; - CRYS_ECPKI_Domain_t *domain = NULL; - - CC_CALLOC_CHECK(UserPrivKey, sizeof( *UserPrivKey )); - CC_CALLOC_CHECK(UserPublKey, sizeof( *UserPublKey )); - CC_CALLOC_CHECK(TempECCKGBuff, sizeof( *TempECCKGBuff )); - CC_CALLOC_CHECK(FipsBuff, sizeof( *FipsBuff )); - CC_CALLOC_CHECK(domain, sizeof( *domain )); - - *domain = *CRYS_ECPKI_GetEcDomain( grp_id ); - - orderSizeInWords = ( domain->ordSizeInBits + ( 8 * sizeof( uint32_t ) ) - 1 ) / - ( 8 * sizeof( uint32_t ) ); - - // Copy generator point from mbedTLS to CryptoCell convention. - mbedtls_mpi_write_binary( &G->X, ( uint8_t * )domain->ecGx, sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_write_binary( &G->Y, ( uint8_t * )domain->ecGy, sizeof( uint32_t ) * orderSizeInWords ); - endianess_swap(domain->ecGx, orderSizeInWords); - endianess_swap(domain->ecGy, orderSizeInWords); - - // Generate keys with CryptoCell. - CRYSError_t error; - CC310_OPERATION(CRYS_ECPKI_GenKeyPair( pRndState, CRYS_RND_GenerateVector, domain, - UserPrivKey, UserPublKey, TempECCKGBuff, FipsBuff ), - error); - - if (error == CRYS_OK) - { - CRYS_ECPKI_PrivKey_t * privateKey = ( CRYS_ECPKI_PrivKey_t * )UserPrivKey->PrivKeyDbBuff; - CRYS_ECPKI_PublKey_t * publicKey = ( CRYS_ECPKI_PublKey_t * )UserPublKey->PublKeyDbBuff; - - // Convert keys from CryptoCell to mbedTLS convention. - mbedtls_mpi_read_binary( d, ( const uint8_t * )privateKey->PrivKey, - sizeof( uint32_t ) * orderSizeInWords ); - endianess_swap(d->p, orderSizeInWords); - - mbedtls_mpi_read_binary( &Q->X, ( const uint8_t * )publicKey->x, - sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_read_binary( &Q->Y, ( const uint8_t * )publicKey->y, - sizeof( uint32_t ) * orderSizeInWords ); - mbedtls_mpi_lset( &Q->Z, 1 ); - endianess_swap( Q->X.p, orderSizeInWords ); - endianess_swap( Q->Y.p, orderSizeInWords ); - - ret = 0; - } - else - { - ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; - } - -cleanup: - - CC_CHECK_FREE(UserPrivKey); - CC_CHECK_FREE(UserPublKey); - CC_CHECK_FREE(TempECCKGBuff); - CC_CHECK_FREE(FipsBuff); - CC_CHECK_FREE(domain); - - return ret; -} - -/* - * Generate a keypair with configurable base point - */ -int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp, - const mbedtls_ecp_point *G, - mbedtls_mpi *d, mbedtls_ecp_point *Q, +int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp, + mbedtls_mpi *d, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) { - int ret; + int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; size_t n_size = ( grp->nbits + 7 ) / 8; #if defined(ECP_MONTGOMERY) @@ -2240,8 +2950,58 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp, MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) ); } } - else #endif /* ECP_MONTGOMERY */ + +#if defined(ECP_SHORTWEIERSTRASS) + if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS ) + { + /* SEC1 3.2.1: Generate d such that 1 <= n < N */ + int count = 0; + + /* + * Match the procedure given in RFC 6979 (deterministic ECDSA): + * - use the same byte ordering; + * - keep the leftmost nbits bits of the generated octet string; + * - try until result is in the desired range. + * This also avoids any biais, which is especially important for ECDSA. + */ + do + { + MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_size, f_rng, p_rng ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, 8 * n_size - grp->nbits ) ); + + /* + * Each try has at worst a probability 1/2 of failing (the msb has + * a probability 1/2 of being 0, and then the result will be < N), + * so after 30 tries failure probability is a most 2**(-30). + * + * For most curves, 1 try is enough with overwhelming probability, + * since N starts with a lot of 1s in binary, but some curves + * such as secp224k1 are actually very close to the worst case. + */ + if( ++count > 30 ) + return( MBEDTLS_ERR_ECP_RANDOM_FAILED ); + } + while( mbedtls_mpi_cmp_int( d, 1 ) < 0 || + mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 ); + } +#endif /* ECP_SHORTWEIERSTRASS */ + +cleanup: + return( ret ); +} + +/* + * Generate a keypair with configurable base point + */ +int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp, + const mbedtls_ecp_point *G, + mbedtls_mpi *d, mbedtls_ecp_point *Q, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) +{ + int ret; + #if defined(ECP_SHORTWEIERSTRASS) if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS ) { @@ -2249,45 +3009,13 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp, if ( cc_id != CRYS_ECPKI_DomainIDLast ) { ret = ecp_gen_keypair_cryptocell( cc_id, G, d, Q ); - } - else - { - /* SEC1 3.2.1: Generate d such that 1 <= n < N */ - int count = 0; - - /* - * Match the procedure given in RFC 6979 (deterministic ECDSA): - * - use the same byte ordering; - * - keep the leftmost nbits bits of the generated octet string; - * - try until result is in the desired range. - * This also avoids any biais, which is especially important for ECDSA. - */ - do - { - MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_size, f_rng, p_rng ) ); - MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, 8 * n_size - grp->nbits ) ); - - /* - * Each try has at worst a probability 1/2 of failing (the msb has - * a probability 1/2 of being 0, and then the result will be < N), - * so after 30 tries failure probability is a most 2**(-30). - * - * For most curves, 1 try is enough with overwhelming probability, - * since N starts with a lot of 1s in binary, but some curves - * such as secp224k1 are actually very close to the worst case. - */ - if( ++count > 30 ) - return( MBEDTLS_ERR_ECP_RANDOM_FAILED ); - } - while( mbedtls_mpi_cmp_int( d, 1 ) < 0 || - mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 ); - - ret = mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ); + return( ret ); } } - else #endif /* ECP_SHORTWEIERSTRASS */ - return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); + + MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) ); cleanup: return( ret ); @@ -2360,4 +3088,137 @@ cleanup: return( ret ); } -#endif /* MBEDTLS_ECP_ALT */ +#if defined(MBEDTLS_SELF_TEST) + +/* + * Checkup routine + */ +int mbedtls_ecp_self_test( int verbose ) +{ + int ret; + size_t i; + mbedtls_ecp_group grp; + mbedtls_ecp_point R, P; + mbedtls_mpi m; + unsigned long add_c_prev, dbl_c_prev, mul_c_prev; + /* exponents especially adapted for secp192r1 */ + const char *exponents[] = + { + "000000000000000000000000000000000000000000000001", /* one */ + "FFFFFFFFFFFFFFFFFFFFFFFF99DEF836146BC9B1B4D22830", /* N - 1 */ + "5EA6F389A38B8BC81E767753B15AA5569E1782E30ABE7D25", /* random */ + "400000000000000000000000000000000000000000000000", /* one and zeros */ + "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", /* all ones */ + "555555555555555555555555555555555555555555555555", /* 101010... */ + }; + + mbedtls_ecp_group_init( &grp ); + mbedtls_ecp_point_init( &R ); + mbedtls_ecp_point_init( &P ); + mbedtls_mpi_init( &m ); + + /* Use secp192r1 if available, or any available curve */ +#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) + MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, MBEDTLS_ECP_DP_SECP192R1 ) ); +#else + MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, mbedtls_ecp_curve_list()->grp_id ) ); +#endif + + if( verbose != 0 ) + mbedtls_printf( " ECP test #1 (constant op_count, base point G): " ); + + /* Do a dummy multiplication first to trigger precomputation */ + MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &m, 2 ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &P, &m, &grp.G, NULL, NULL ) ); + + add_count = 0; + dbl_count = 0; + mul_count = 0; + MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[0] ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &grp.G, NULL, NULL ) ); + + for( i = 1; i < sizeof( exponents ) / sizeof( exponents[0] ); i++ ) + { + add_c_prev = add_count; + dbl_c_prev = dbl_count; + mul_c_prev = mul_count; + add_count = 0; + dbl_count = 0; + mul_count = 0; + + MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[i] ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &grp.G, NULL, NULL ) ); + + if( add_count != add_c_prev || + dbl_count != dbl_c_prev || + mul_count != mul_c_prev ) + { + if( verbose != 0 ) + mbedtls_printf( "failed (%u)\n", (unsigned int) i ); + + ret = 1; + goto cleanup; + } + } + + if( verbose != 0 ) + mbedtls_printf( "passed\n" ); + + if( verbose != 0 ) + mbedtls_printf( " ECP test #2 (constant op_count, other point): " ); + /* We computed P = 2G last time, use it */ + + add_count = 0; + dbl_count = 0; + mul_count = 0; + MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[0] ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &P, NULL, NULL ) ); + + for( i = 1; i < sizeof( exponents ) / sizeof( exponents[0] ); i++ ) + { + add_c_prev = add_count; + dbl_c_prev = dbl_count; + mul_c_prev = mul_count; + add_count = 0; + dbl_count = 0; + mul_count = 0; + + MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[i] ) ); + MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &P, NULL, NULL ) ); + + if( add_count != add_c_prev || + dbl_count != dbl_c_prev || + mul_count != mul_c_prev ) + { + if( verbose != 0 ) + mbedtls_printf( "failed (%u)\n", (unsigned int) i ); + + ret = 1; + goto cleanup; + } + } + + if( verbose != 0 ) + mbedtls_printf( "passed\n" ); + +cleanup: + + if( ret < 0 && verbose != 0 ) + mbedtls_printf( "Unexpected error, return code = %08X\n", ret ); + + mbedtls_ecp_group_free( &grp ); + mbedtls_ecp_point_free( &R ); + mbedtls_ecp_point_free( &P ); + mbedtls_mpi_free( &m ); + + if( verbose != 0 ) + mbedtls_printf( "\n" ); + + return( ret ); +} + +#endif /* MBEDTLS_SELF_TEST */ + +#endif /* !MBEDTLS_ECP_ALT */ + +#endif /* MBEDTLS_ECP_C */