From a306d20766e89d5598e3cee0f9940cf0a088a757 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Tue, 6 Jun 2023 17:15:52 +0200 Subject: [PATCH 01/11] Clone the ecp.c file as ecp_new.c Add macro guard for each file defaults to enable the ecp.c file content. Signed-off-by: Gabor Mezei --- library/ecp.c | 7 +- library/ecp_invasive.h | 8 + library/ecp_new.c | 3652 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 3666 insertions(+), 1 deletion(-) create mode 100644 library/ecp_new.c diff --git a/library/ecp.c b/library/ecp.c index 086acb35e..1d690d1ad 100644 --- a/library/ecp.c +++ b/library/ecp.c @@ -43,6 +43,10 @@ #include "common.h" +#include "ecp_invasive.h" + +#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT) + /** * \brief Function level alternative implementation. * @@ -80,7 +84,6 @@ #include "mbedtls/error.h" #include "bn_mul.h" -#include "ecp_invasive.h" #include @@ -3639,3 +3642,5 @@ cleanup: #endif /* !MBEDTLS_ECP_ALT */ #endif /* MBEDTLS_ECP_LIGHT */ + +#endif /* MBEDTLS_ECP_WITH_MPI_STRUCT */ diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 94867b90e..0ea02e285 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -40,6 +40,14 @@ typedef enum { MBEDTLS_ECP_MOD_SCALAR } mbedtls_ecp_modulus_type; +#ifndef MBEDTLS_ECP_WITH_MPI_UINT + +#define MBEDTLS_ECP_WITH_MPI_UINT +#undef MBEDTLS_ECP_WITH_MPI_UINT + +#define MBEDTLS_ECP_WITH_MPI_STRUCT +#endif + #if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_ECP_LIGHT) #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) diff --git a/library/ecp_new.c b/library/ecp_new.c new file mode 100644 index 000000000..c212f6323 --- /dev/null +++ b/library/ecp_new.c @@ -0,0 +1,3652 @@ +/* + * Elliptic curves over GF(p): generic functions + * + * Copyright The Mbed TLS Contributors + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* + * References: + * + * SEC1 https://www.secg.org/sec1-v2.pdf + * GECC = Guide to Elliptic Curve Cryptography - Hankerson, Menezes, Vanstone + * FIPS 186-3 http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf + * RFC 4492 for the related TLS structures and constants + * - https://www.rfc-editor.org/rfc/rfc4492 + * RFC 7748 for the Curve448 and Curve25519 curve definitions + * - https://www.rfc-editor.org/rfc/rfc7748 + * + * [Curve25519] https://cr.yp.to/ecdh/curve25519-20060209.pdf + * + * [2] CORON, Jean-S'ebastien. Resistance against differential power analysis + * for elliptic curve cryptosystems. In : Cryptographic Hardware and + * Embedded Systems. Springer Berlin Heidelberg, 1999. p. 292-302. + * + * + * [3] HEDABOU, Mustapha, PINEL, Pierre, et B'EN'ETEAU, Lucien. A comb method to + * render ECC resistant against Side Channel Attacks. IACR Cryptology + * ePrint Archive, 2004, vol. 2004, p. 342. + * + */ + +#include "common.h" + +#include "ecp_invasive.h" + +#if defined(MBEDTLS_ECP_WITH_MPI_UINT) + +/** + * \brief Function level alternative implementation. + * + * The MBEDTLS_ECP_INTERNAL_ALT macro enables alternative implementations to + * replace certain functions in this module. The alternative implementations are + * typically hardware accelerators and need to activate the hardware before the + * computation starts and deactivate it after it finishes. The + * mbedtls_internal_ecp_init() and mbedtls_internal_ecp_free() functions serve + * this purpose. + * + * To preserve the correct functionality the following conditions must hold: + * + * - The alternative implementation must be activated by + * mbedtls_internal_ecp_init() before any of the replaceable functions is + * called. + * - mbedtls_internal_ecp_free() must \b only be called when the alternative + * implementation is activated. + * - mbedtls_internal_ecp_init() must \b not be called when the alternative + * implementation is activated. + * - Public functions must not return while the alternative implementation is + * activated. + * - Replaceable functions are guarded by \c MBEDTLS_ECP_XXX_ALT macros and + * before calling them an \code if( mbedtls_internal_ecp_grp_capable( grp ) ) + * \endcode ensures that the alternative implementation supports the current + * group. + */ +#if defined(MBEDTLS_ECP_INTERNAL_ALT) +#endif + +#if defined(MBEDTLS_ECP_LIGHT) + +#include "mbedtls/ecp.h" +#include "mbedtls/threading.h" +#include "mbedtls/platform_util.h" +#include "mbedtls/error.h" + +#include "bn_mul.h" + +#include + +#if !defined(MBEDTLS_ECP_ALT) + +#include "mbedtls/platform.h" + +#include "ecp_internal_alt.h" + +#if defined(MBEDTLS_SELF_TEST) +/* + * Counts of point addition and doubling, and field multiplications. + * Used to test resistance of point multiplication to simple timing attacks. + */ +#if defined(MBEDTLS_ECP_C) +static unsigned long add_count, dbl_count; +#endif /* MBEDTLS_ECP_C */ +static unsigned long mul_count; +#endif + +#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_C) +static void mpi_init_many(mbedtls_mpi *arr, size_t size) +{ + while (size--) { + mbedtls_mpi_init(arr++); + } +} + +static void mpi_free_many(mbedtls_mpi *arr, size_t size) +{ + while (size--) { + mbedtls_mpi_free(arr++); + } +} +#endif /* MBEDTLS_ECP_C */ + +/* + * List of supported curves: + * - internal ID + * - TLS NamedCurve ID (RFC 4492 sec. 5.1.1, RFC 7071 sec. 2, RFC 8446 sec. 4.2.7) + * - size in bits + * - readable name + * + * Curves are listed in order: largest curves first, and for a given size, + * fastest curves first. + * + * Reminder: update profiles in x509_crt.c and ssl_tls.c when adding a new curve! + */ +static const mbedtls_ecp_curve_info ecp_supported_curves[] = +{ +#if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) + { MBEDTLS_ECP_DP_SECP521R1, 25, 521, "secp521r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) + { MBEDTLS_ECP_DP_BP512R1, 28, 512, "brainpoolP512r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) + { MBEDTLS_ECP_DP_SECP384R1, 24, 384, "secp384r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) + { MBEDTLS_ECP_DP_BP384R1, 27, 384, "brainpoolP384r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) + { MBEDTLS_ECP_DP_SECP256R1, 23, 256, "secp256r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) + { MBEDTLS_ECP_DP_SECP256K1, 22, 256, "secp256k1" }, +#endif +#if defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) + { MBEDTLS_ECP_DP_BP256R1, 26, 256, "brainpoolP256r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) + { MBEDTLS_ECP_DP_SECP224R1, 21, 224, "secp224r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) + { MBEDTLS_ECP_DP_SECP224K1, 20, 224, "secp224k1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) + { MBEDTLS_ECP_DP_SECP192R1, 19, 192, "secp192r1" }, +#endif +#if defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) + { MBEDTLS_ECP_DP_SECP192K1, 18, 192, "secp192k1" }, +#endif +#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) + { MBEDTLS_ECP_DP_CURVE25519, 29, 256, "x25519" }, +#endif +#if defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) + { MBEDTLS_ECP_DP_CURVE448, 30, 448, "x448" }, +#endif + { MBEDTLS_ECP_DP_NONE, 0, 0, NULL }, +}; + +#define ECP_NB_CURVES sizeof(ecp_supported_curves) / \ + sizeof(ecp_supported_curves[0]) + +static mbedtls_ecp_group_id ecp_supported_grp_id[ECP_NB_CURVES]; + +/* + * List of supported curves and associated info + */ +const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list(void) +{ + return ecp_supported_curves; +} + +/* + * List of supported curves, group ID only + */ +const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list(void) +{ + static int init_done = 0; + + if (!init_done) { + size_t i = 0; + const mbedtls_ecp_curve_info *curve_info; + + for (curve_info = mbedtls_ecp_curve_list(); + curve_info->grp_id != MBEDTLS_ECP_DP_NONE; + curve_info++) { + ecp_supported_grp_id[i++] = curve_info->grp_id; + } + ecp_supported_grp_id[i] = MBEDTLS_ECP_DP_NONE; + + init_done = 1; + } + + return ecp_supported_grp_id; +} + +/* + * Get the curve info for the internal identifier + */ +const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id(mbedtls_ecp_group_id grp_id) +{ + const mbedtls_ecp_curve_info *curve_info; + + for (curve_info = mbedtls_ecp_curve_list(); + curve_info->grp_id != MBEDTLS_ECP_DP_NONE; + curve_info++) { + if (curve_info->grp_id == grp_id) { + return curve_info; + } + } + + return NULL; +} + +/* + * Get the curve info from the TLS identifier + */ +const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id(uint16_t tls_id) +{ + const mbedtls_ecp_curve_info *curve_info; + + for (curve_info = mbedtls_ecp_curve_list(); + curve_info->grp_id != MBEDTLS_ECP_DP_NONE; + curve_info++) { + if (curve_info->tls_id == tls_id) { + return curve_info; + } + } + + return NULL; +} + +/* + * Get the curve info from the name + */ +const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name(const char *name) +{ + const mbedtls_ecp_curve_info *curve_info; + + if (name == NULL) { + return NULL; + } + + for (curve_info = mbedtls_ecp_curve_list(); + curve_info->grp_id != MBEDTLS_ECP_DP_NONE; + curve_info++) { + if (strcmp(curve_info->name, name) == 0) { + return curve_info; + } + } + + return NULL; +} + +/* + * Get the type of a curve + */ +mbedtls_ecp_curve_type mbedtls_ecp_get_type(const mbedtls_ecp_group *grp) +{ + if (grp->G.X.p == NULL) { + return MBEDTLS_ECP_TYPE_NONE; + } + + if (grp->G.Y.p == NULL) { + return MBEDTLS_ECP_TYPE_MONTGOMERY; + } else { + return MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS; + } +} + +/* + * Initialize (the components of) a point + */ +void mbedtls_ecp_point_init(mbedtls_ecp_point *pt) +{ + mbedtls_mpi_init(&pt->X); + mbedtls_mpi_init(&pt->Y); + mbedtls_mpi_init(&pt->Z); +} + +/* + * Initialize (the components of) a group + */ +void mbedtls_ecp_group_init(mbedtls_ecp_group *grp) +{ + 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; +} + +/* + * Initialize (the components of) a key pair + */ +void mbedtls_ecp_keypair_init(mbedtls_ecp_keypair *key) +{ + mbedtls_ecp_group_init(&key->grp); + mbedtls_mpi_init(&key->d); + mbedtls_ecp_point_init(&key->Q); +} + +/* + * Unallocate (the components of) a point + */ +void mbedtls_ecp_point_free(mbedtls_ecp_point *pt) +{ + if (pt == NULL) { + return; + } + + mbedtls_mpi_free(&(pt->X)); + mbedtls_mpi_free(&(pt->Y)); + mbedtls_mpi_free(&(pt->Z)); +} + +/* + * Check that the comb table (grp->T) is static initialized. + */ +static int ecp_group_is_static_comb_table(const mbedtls_ecp_group *grp) +{ +#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1 + return grp->T != NULL && grp->T_size == 0; +#else + (void) grp; + return 0; +#endif +} + +/* + * Unallocate (the components of) a group + */ +void mbedtls_ecp_group_free(mbedtls_ecp_group *grp) +{ + size_t i; + + if (grp == NULL) { + return; + } + + if (grp->h != 1) { + mbedtls_mpi_free(&grp->A); + mbedtls_mpi_free(&grp->B); + mbedtls_ecp_point_free(&grp->G); + } + + if (!ecp_group_is_static_comb_table(grp) && grp->T != NULL) { + for (i = 0; i < grp->T_size; i++) { + mbedtls_ecp_point_free(&grp->T[i]); + } + mbedtls_free(grp->T); + } + + mbedtls_platform_zeroize(grp, sizeof(mbedtls_ecp_group)); +} + +/* + * Unallocate (the components of) a key pair + */ +void mbedtls_ecp_keypair_free(mbedtls_ecp_keypair *key) +{ + if (key == NULL) { + return; + } + + mbedtls_ecp_group_free(&key->grp); + mbedtls_mpi_free(&key->d); + mbedtls_ecp_point_free(&key->Q); +} + +/* + * Copy the contents of a point + */ +int mbedtls_ecp_copy(mbedtls_ecp_point *P, const mbedtls_ecp_point *Q) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&P->X, &Q->X)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&P->Y, &Q->Y)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&P->Z, &Q->Z)); + +cleanup: + return ret; +} + +/* + * Copy the contents of a group object + */ +int mbedtls_ecp_group_copy(mbedtls_ecp_group *dst, const mbedtls_ecp_group *src) +{ + return mbedtls_ecp_group_load(dst, src->id); +} + +/* + * Set point to zero + */ +int mbedtls_ecp_set_zero(mbedtls_ecp_point *pt) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&pt->X, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&pt->Y, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&pt->Z, 0)); + +cleanup: + return ret; +} + +/* + * Tell if a point is zero + */ +int mbedtls_ecp_is_zero(mbedtls_ecp_point *pt) +{ + return mbedtls_mpi_cmp_int(&pt->Z, 0) == 0; +} + +/* + * Compare two points lazily + */ +int mbedtls_ecp_point_cmp(const mbedtls_ecp_point *P, + const mbedtls_ecp_point *Q) +{ + if (mbedtls_mpi_cmp_mpi(&P->X, &Q->X) == 0 && + mbedtls_mpi_cmp_mpi(&P->Y, &Q->Y) == 0 && + mbedtls_mpi_cmp_mpi(&P->Z, &Q->Z) == 0) { + return 0; + } + + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +} + +/* + * Import a non-zero point from ASCII strings + */ +int mbedtls_ecp_point_read_string(mbedtls_ecp_point *P, int radix, + const char *x, const char *y) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&P->X, radix, x)); + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&P->Y, radix, y)); + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&P->Z, 1)); + +cleanup: + return ret; +} + +/* + * Export a point into unsigned binary data (SEC1 2.3.3 and RFC7748) + */ +int mbedtls_ecp_point_write_binary(const mbedtls_ecp_group *grp, + const mbedtls_ecp_point *P, + int format, size_t *olen, + unsigned char *buf, size_t buflen) +{ + int ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + size_t plen; + if (format != MBEDTLS_ECP_PF_UNCOMPRESSED && + format != MBEDTLS_ECP_PF_COMPRESSED) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + plen = mbedtls_mpi_size(&grp->P); + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + (void) format; /* Montgomery curves always use the same point format */ + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + *olen = plen; + if (buflen < *olen) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary_le(&P->X, buf, plen)); + } +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + /* + * Common case: P == 0 + */ + if (mbedtls_mpi_cmp_int(&P->Z, 0) == 0) { + if (buflen < 1) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + buf[0] = 0x00; + *olen = 1; + + return 0; + } + + if (format == MBEDTLS_ECP_PF_UNCOMPRESSED) { + *olen = 2 * plen + 1; + + if (buflen < *olen) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + buf[0] = 0x04; + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&P->X, buf + 1, plen)); + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&P->Y, buf + 1 + plen, plen)); + } else if (format == MBEDTLS_ECP_PF_COMPRESSED) { + *olen = plen + 1; + + if (buflen < *olen) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + buf[0] = 0x02 + mbedtls_mpi_get_bit(&P->Y, 0); + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&P->X, buf + 1, plen)); + } + } +#endif + +cleanup: + return ret; +} + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) +static int mbedtls_ecp_sw_derive_y(const mbedtls_ecp_group *grp, + const mbedtls_mpi *X, + mbedtls_mpi *Y, + int parity_bit); +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +/* + * Import a point from unsigned binary data (SEC1 2.3.4 and RFC7748) + */ +int mbedtls_ecp_point_read_binary(const mbedtls_ecp_group *grp, + mbedtls_ecp_point *pt, + const unsigned char *buf, size_t ilen) +{ + int ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + size_t plen; + if (ilen < 1) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + plen = mbedtls_mpi_size(&grp->P); + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + if (plen != ilen) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary_le(&pt->X, buf, plen)); + mbedtls_mpi_free(&pt->Y); + + if (grp->id == MBEDTLS_ECP_DP_CURVE25519) { + /* Set most significant bit to 0 as prescribed in RFC7748 ยง5 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&pt->X, plen * 8 - 1, 0)); + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&pt->Z, 1)); + } +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + if (buf[0] == 0x00) { + if (ilen == 1) { + return mbedtls_ecp_set_zero(pt); + } else { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + } + + if (ilen < 1 + plen) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&pt->X, buf + 1, plen)); + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&pt->Z, 1)); + + if (buf[0] == 0x04) { + /* format == MBEDTLS_ECP_PF_UNCOMPRESSED */ + if (ilen != 1 + plen * 2) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + return mbedtls_mpi_read_binary(&pt->Y, buf + 1 + plen, plen); + } else if (buf[0] == 0x02 || buf[0] == 0x03) { + /* format == MBEDTLS_ECP_PF_COMPRESSED */ + if (ilen != 1 + plen) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + return mbedtls_ecp_sw_derive_y(grp, &pt->X, &pt->Y, + (buf[0] & 1)); + } else { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + } +#endif + +cleanup: + return ret; +} + +/* + * Import a point from a TLS ECPoint record (RFC 4492) + * struct { + * opaque point <1..2^8-1>; + * } ECPoint; + */ +int mbedtls_ecp_tls_read_point(const mbedtls_ecp_group *grp, + mbedtls_ecp_point *pt, + const unsigned char **buf, size_t buf_len) +{ + unsigned char data_len; + const unsigned char *buf_start; + /* + * We must have at least two bytes (1 for length, at least one for data) + */ + if (buf_len < 2) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + data_len = *(*buf)++; + if (data_len < 1 || data_len > buf_len - 1) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * Save buffer start for read_binary and update buf + */ + buf_start = *buf; + *buf += data_len; + + return mbedtls_ecp_point_read_binary(grp, pt, buf_start, data_len); +} + +/* + * Export a point as a TLS ECPoint record (RFC 4492) + * struct { + * opaque point <1..2^8-1>; + * } ECPoint; + */ +int mbedtls_ecp_tls_write_point(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt, + int format, size_t *olen, + unsigned char *buf, size_t blen) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + if (format != MBEDTLS_ECP_PF_UNCOMPRESSED && + format != MBEDTLS_ECP_PF_COMPRESSED) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * buffer length must be at least one, for our length byte + */ + if (blen < 1) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + if ((ret = mbedtls_ecp_point_write_binary(grp, pt, format, + olen, buf + 1, blen - 1)) != 0) { + return ret; + } + + /* + * write length to the first byte and update total length + */ + buf[0] = (unsigned char) *olen; + ++*olen; + + return 0; +} + +/* + * Set a group from an ECParameters record (RFC 4492) + */ +int mbedtls_ecp_tls_read_group(mbedtls_ecp_group *grp, + const unsigned char **buf, size_t len) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_ecp_group_id grp_id; + if ((ret = mbedtls_ecp_tls_read_group_id(&grp_id, buf, len)) != 0) { + return ret; + } + + return mbedtls_ecp_group_load(grp, grp_id); +} + +/* + * Read a group id from an ECParameters record (RFC 4492) and convert it to + * mbedtls_ecp_group_id. + */ +int mbedtls_ecp_tls_read_group_id(mbedtls_ecp_group_id *grp, + const unsigned char **buf, size_t len) +{ + uint16_t tls_id; + const mbedtls_ecp_curve_info *curve_info; + /* + * We expect at least three bytes (see below) + */ + if (len < 3) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * First byte is curve_type; only named_curve is handled + */ + if (*(*buf)++ != MBEDTLS_ECP_TLS_NAMED_CURVE) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * Next two bytes are the namedcurve value + */ + tls_id = *(*buf)++; + tls_id <<= 8; + tls_id |= *(*buf)++; + + if ((curve_info = mbedtls_ecp_curve_info_from_tls_id(tls_id)) == NULL) { + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + } + + *grp = curve_info->grp_id; + + return 0; +} + +/* + * Write the ECParameters record corresponding to a group (RFC 4492) + */ +int mbedtls_ecp_tls_write_group(const mbedtls_ecp_group *grp, size_t *olen, + unsigned char *buf, size_t blen) +{ + const mbedtls_ecp_curve_info *curve_info; + if ((curve_info = mbedtls_ecp_curve_info_from_grp_id(grp->id)) == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * We are going to write 3 bytes (see below) + */ + *olen = 3; + if (blen < *olen) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + /* + * First byte is curve_type, always named_curve + */ + *buf++ = MBEDTLS_ECP_TLS_NAMED_CURVE; + + /* + * Next two bytes are the namedcurve value + */ + MBEDTLS_PUT_UINT16_BE(curve_info->tls_id, buf, 0); + + return 0; +} + +/* + * Wrapper around fast quasi-modp functions, with fall-back to mbedtls_mpi_mod_mpi. + * See the documentation of struct mbedtls_ecp_group. + * + * This function is in the critial loop for mbedtls_ecp_mul, so pay attention to perf. + */ +static int ecp_modp(mbedtls_mpi *N, const mbedtls_ecp_group *grp) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if (grp->modp == NULL) { + return mbedtls_mpi_mod_mpi(N, N, &grp->P); + } + + /* N->s < 0 is a much faster test, which fails only if N is 0 */ + if ((N->s < 0 && mbedtls_mpi_cmp_int(N, 0) != 0) || + mbedtls_mpi_bitlen(N) > 2 * grp->pbits) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + MBEDTLS_MPI_CHK(grp->modp(N)); + + /* N->s < 0 is a much faster test, which fails only if N is 0 */ + while (N->s < 0 && mbedtls_mpi_cmp_int(N, 0) != 0) { + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(N, N, &grp->P)); + } + + while (mbedtls_mpi_cmp_mpi(N, &grp->P) >= 0) { + /* we known P, N and the result are positive */ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_abs(N, N, &grp->P)); + } + +cleanup: + return ret; +} + +/* + * Fast mod-p functions expect their argument to be in the 0..p^2 range. + * + * In order to guarantee that, we need to ensure that operands of + * mbedtls_mpi_mul_mpi are in the 0..p range. So, after each operation we will + * bring the result back to this range. + * + * The following macros are shortcuts for doing that. + */ + +/* + * Reduce a mbedtls_mpi mod p in-place, general case, to use after mbedtls_mpi_mul_mpi + */ +#if defined(MBEDTLS_SELF_TEST) +#define INC_MUL_COUNT mul_count++; +#else +#define INC_MUL_COUNT +#endif + +#define MOD_MUL(N) \ + do \ + { \ + MBEDTLS_MPI_CHK(ecp_modp(&(N), grp)); \ + INC_MUL_COUNT \ + } while (0) + +static inline int mbedtls_mpi_mul_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + const mbedtls_mpi *A, + const mbedtls_mpi *B) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(X, A, B)); + MOD_MUL(*X); +cleanup: + return ret; +} + +/* + * Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_sub_mpi + * N->s < 0 is a very fast test, which fails only if N is 0 + */ +#define MOD_SUB(N) \ + do { \ + while ((N)->s < 0 && mbedtls_mpi_cmp_int((N), 0) != 0) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi((N), (N), &grp->P)); \ + } while (0) + +#if (defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) && \ + !(defined(MBEDTLS_ECP_NO_FALLBACK) && \ + defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) && \ + defined(MBEDTLS_ECP_ADD_MIXED_ALT))) || \ + (defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) && \ + !(defined(MBEDTLS_ECP_NO_FALLBACK) && \ + defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT))) +static inline int mbedtls_mpi_sub_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + const mbedtls_mpi *A, + const mbedtls_mpi *B) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(X, A, B)); + MOD_SUB(X); +cleanup: + return ret; +} +#endif /* All functions referencing mbedtls_mpi_sub_mod() are alt-implemented without fallback */ + +/* + * Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_add_mpi and mbedtls_mpi_mul_int. + * We known P, N and the result are positive, so sub_abs is correct, and + * a bit faster. + */ +#define MOD_ADD(N) \ + while (mbedtls_mpi_cmp_mpi((N), &grp->P) >= 0) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_abs((N), (N), &grp->P)) + +static inline int mbedtls_mpi_add_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + const mbedtls_mpi *A, + const mbedtls_mpi *B) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(X, A, B)); + MOD_ADD(X); +cleanup: + return ret; +} + +static inline int mbedtls_mpi_mul_int_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + const mbedtls_mpi *A, + mbedtls_mpi_uint c) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_int(X, A, c)); + MOD_ADD(X); +cleanup: + return ret; +} + +static inline int mbedtls_mpi_sub_int_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + const mbedtls_mpi *A, + mbedtls_mpi_uint c) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(X, A, c)); + MOD_SUB(X); +cleanup: + return ret; +} + +#define MPI_ECP_SUB_INT(X, A, c) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int_mod(grp, X, A, c)) + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) && \ + !(defined(MBEDTLS_ECP_NO_FALLBACK) && \ + defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) && \ + defined(MBEDTLS_ECP_ADD_MIXED_ALT)) +static inline int mbedtls_mpi_shift_l_mod(const mbedtls_ecp_group *grp, + mbedtls_mpi *X, + size_t count) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_MPI_CHK(mbedtls_mpi_shift_l(X, count)); + MOD_ADD(X); +cleanup: + return ret; +} +#endif \ + /* All functions referencing mbedtls_mpi_shift_l_mod() are alt-implemented without fallback */ + +/* + * Macro wrappers around ECP modular arithmetic + * + * Currently, these wrappers are defined via the bignum module. + */ + +#define MPI_ECP_ADD(X, A, B) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mod(grp, X, A, B)) + +#define MPI_ECP_SUB(X, A, B) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mod(grp, X, A, B)) + +#define MPI_ECP_MUL(X, A, B) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mod(grp, X, A, B)) + +#define MPI_ECP_SQR(X, A) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mod(grp, X, A, A)) + +#define MPI_ECP_MUL_INT(X, A, c) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_int_mod(grp, X, A, c)) + +#define MPI_ECP_INV(dst, src) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod((dst), (src), &grp->P)) + +#define MPI_ECP_MOV(X, A) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(X, A)) + +#define MPI_ECP_SHIFT_L(X, count) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_shift_l_mod(grp, X, count)) + +#define MPI_ECP_LSET(X, c) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(X, c)) + +#define MPI_ECP_CMP_INT(X, c) \ + mbedtls_mpi_cmp_int(X, c) + +#define MPI_ECP_CMP(X, Y) \ + mbedtls_mpi_cmp_mpi(X, Y) + +/* Needs f_rng, p_rng to be defined. */ +#define MPI_ECP_RAND(X) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_random((X), 2, &grp->P, f_rng, p_rng)) + +/* Conditional negation + * Needs grp and a temporary MPI tmp to be defined. */ +#define MPI_ECP_COND_NEG(X, cond) \ + do \ + { \ + unsigned char nonzero = mbedtls_mpi_cmp_int((X), 0) != 0; \ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&tmp, &grp->P, (X))); \ + MBEDTLS_MPI_CHK(mbedtls_mpi_safe_cond_assign((X), &tmp, \ + nonzero & cond)); \ + } while (0) + +#define MPI_ECP_NEG(X) MPI_ECP_COND_NEG((X), 1) + +#define MPI_ECP_VALID(X) \ + ((X)->p != NULL) + +#define MPI_ECP_COND_ASSIGN(X, Y, cond) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_safe_cond_assign((X), (Y), (cond))) + +#define MPI_ECP_COND_SWAP(X, Y, cond) \ + MBEDTLS_MPI_CHK(mbedtls_mpi_safe_cond_swap((X), (Y), (cond))) + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + +/* + * Computes the right-hand side of the Short Weierstrass equation + * RHS = X^3 + A X + B + */ +static int ecp_sw_rhs(const mbedtls_ecp_group *grp, + mbedtls_mpi *rhs, + const mbedtls_mpi *X) +{ + int ret; + + /* Compute X^3 + A X + B as X (X^2 + A) + B */ + MPI_ECP_SQR(rhs, X); + + /* Special case for A = -3 */ + if (grp->A.p == NULL) { + MPI_ECP_SUB_INT(rhs, rhs, 3); + } else { + MPI_ECP_ADD(rhs, rhs, &grp->A); + } + + MPI_ECP_MUL(rhs, rhs, X); + MPI_ECP_ADD(rhs, rhs, &grp->B); + +cleanup: + return ret; +} + +/* + * Derive Y from X and a parity bit + */ +static int mbedtls_ecp_sw_derive_y(const mbedtls_ecp_group *grp, + const mbedtls_mpi *X, + mbedtls_mpi *Y, + int parity_bit) +{ + /* w = y^2 = x^3 + ax + b + * y = sqrt(w) = w^((p+1)/4) mod p (for prime p where p = 3 mod 4) + * + * Note: this method for extracting square root does not validate that w + * was indeed a square so this function will return garbage in Y if X + * does not correspond to a point on the curve. + */ + + /* Check prerequisite p = 3 mod 4 */ + if (mbedtls_mpi_get_bit(&grp->P, 0) != 1 || + mbedtls_mpi_get_bit(&grp->P, 1) != 1) { + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + } + + int ret; + mbedtls_mpi exp; + mbedtls_mpi_init(&exp); + + /* use Y to store intermediate result, actually w above */ + MBEDTLS_MPI_CHK(ecp_sw_rhs(grp, Y, X)); + + /* w = y^2 */ /* Y contains y^2 intermediate result */ + /* exp = ((p+1)/4) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&exp, &grp->P, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_shift_r(&exp, 2)); + /* sqrt(w) = w^((p+1)/4) mod p (for prime p where p = 3 mod 4) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(Y, Y /*y^2*/, &exp, &grp->P, NULL)); + + /* check parity bit match or else invert Y */ + /* This quick inversion implementation is valid because Y != 0 for all + * Short Weierstrass curves supported by mbedtls, as each supported curve + * has an order that is a large prime, so each supported curve does not + * have any point of order 2, and a point with Y == 0 would be of order 2 */ + if (mbedtls_mpi_get_bit(Y, 0) != parity_bit) { + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(Y, &grp->P, Y)); + } + +cleanup: + + mbedtls_mpi_free(&exp); + return ret; +} +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +#if defined(MBEDTLS_ECP_C) +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) +/* + * For curves in short Weierstrass form, we do all the internal operations in + * Jacobian coordinates. + * + * For multiplication, we'll use a comb method with countermeasures against + * SPA, hence timing attacks. + */ + +/* + * Normalize jacobian coordinates so that Z == 0 || Z == 1 (GECC 3.2.1) + * Cost: 1N := 1I + 3M + 1S + */ +static int ecp_normalize_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt) +{ + if (MPI_ECP_CMP_INT(&pt->Z, 0) == 0) { + return 0; + } + +#if defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT) + if (mbedtls_internal_ecp_grp_capable(grp)) { + return mbedtls_internal_ecp_normalize_jac(grp, pt); + } +#endif /* MBEDTLS_ECP_NORMALIZE_JAC_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi T; + mbedtls_mpi_init(&T); + + MPI_ECP_INV(&T, &pt->Z); /* T <- 1 / Z */ + MPI_ECP_MUL(&pt->Y, &pt->Y, &T); /* Y' <- Y*T = Y / Z */ + MPI_ECP_SQR(&T, &T); /* T <- T^2 = 1 / Z^2 */ + MPI_ECP_MUL(&pt->X, &pt->X, &T); /* X <- X * T = X / Z^2 */ + MPI_ECP_MUL(&pt->Y, &pt->Y, &T); /* Y'' <- Y' * T = Y / Z^3 */ + + MPI_ECP_LSET(&pt->Z, 1); + +cleanup: + + mbedtls_mpi_free(&T); + + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT) */ +} + +/* + * Normalize jacobian coordinates of an array of (pointers to) points, + * using Montgomery's trick to perform only one inversion mod P. + * (See for example Cohen's "A Course in Computational Algebraic Number + * Theory", Algorithm 10.3.4.) + * + * Warning: fails (returning an error) if one of the points is zero! + * This should never happen, see choice of w in ecp_mul_comb(). + * + * 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_size) +{ + 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_size); + } +#endif + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t i; + mbedtls_mpi *c, t; + + if ((c = mbedtls_calloc(T_size, sizeof(mbedtls_mpi))) == NULL) { + return MBEDTLS_ERR_ECP_ALLOC_FAILED; + } + + mbedtls_mpi_init(&t); + + mpi_init_many(c, T_size); + /* + * c[i] = Z_0 * ... * Z_i, i = 0,..,n := T_size-1 + */ + MPI_ECP_MOV(&c[0], &T[0]->Z); + for (i = 1; i < T_size; i++) { + MPI_ECP_MUL(&c[i], &c[i-1], &T[i]->Z); + } + + /* + * c[n] = 1 / (Z_0 * ... * Z_n) mod P + */ + MPI_ECP_INV(&c[T_size-1], &c[T_size-1]); + + for (i = T_size - 1;; i--) { + /* At the start of iteration i (note that i decrements), we have + * - c[j] = Z_0 * .... * Z_j for j < i, + * - c[j] = 1 / (Z_0 * .... * Z_j) for j == i, + * + * This is maintained via + * - c[i-1] <- c[i] * Z_i + * + * We also derive 1/Z_i = c[i] * c[i-1] for i>0 and use that + * to do the actual normalization. For i==0, we already have + * c[0] = 1 / Z_0. + */ + + if (i > 0) { + /* Compute 1/Z_i and establish invariant for the next iteration. */ + MPI_ECP_MUL(&t, &c[i], &c[i-1]); + MPI_ECP_MUL(&c[i-1], &c[i], &T[i]->Z); + } else { + MPI_ECP_MOV(&t, &c[0]); + } + + /* Now t holds 1 / Z_i; normalize as in ecp_normalize_jac() */ + MPI_ECP_MUL(&T[i]->Y, &T[i]->Y, &t); + MPI_ECP_SQR(&t, &t); + MPI_ECP_MUL(&T[i]->X, &T[i]->X, &t); + MPI_ECP_MUL(&T[i]->Y, &T[i]->Y, &t); + + /* + * Post-precessing: reclaim some memory by shrinking coordinates + * - not storing Z (always 1) + * - shrinking other coordinates, but still keeping the same number of + * limbs as P, as otherwise it will too likely be regrown too fast. + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_shrink(&T[i]->X, grp->P.n)); + MBEDTLS_MPI_CHK(mbedtls_mpi_shrink(&T[i]->Y, grp->P.n)); + + MPI_ECP_LSET(&T[i]->Z, 1); + + if (i == 0) { + break; + } + } + +cleanup: + + mbedtls_mpi_free(&t); + mpi_free_many(c, T_size); + mbedtls_free(c); + + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT) */ +} + +/* + * Conditional point inversion: Q -> -Q = (Q.X, -Q.Y, Q.Z) without leak. + * "inv" must be 0 (don't invert) or 1 (invert) or the result will be invalid + */ +static int ecp_safe_invert_jac(const mbedtls_ecp_group *grp, + mbedtls_ecp_point *Q, + unsigned char inv) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi tmp; + mbedtls_mpi_init(&tmp); + + MPI_ECP_COND_NEG(&Q->Y, inv); + +cleanup: + mbedtls_mpi_free(&tmp); + return ret; +} + +/* + * Point doubling R = 2 P, Jacobian coordinates + * + * Based on http://www.hyperelliptic.org/EFD/g1p/auto-shortw-jacobian.html#doubling-dbl-1998-cmo-2 . + * + * We follow the variable naming fairly closely. The formula variations that trade a MUL for a SQR + * (plus a few ADDs) aren't useful as our bignum implementation doesn't distinguish squaring. + * + * Standard optimizations are applied when curve parameter A is one of { 0, -3 }. + * + * Cost: 1D := 3M + 4S (A == 0) + * 4M + 4S (A == -3) + * 3M + 6S + 1a otherwise + */ +static int ecp_double_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, + const mbedtls_ecp_point *P, + mbedtls_mpi tmp[4]) +{ +#if defined(MBEDTLS_SELF_TEST) + dbl_count++; +#endif + +#if defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) + if (mbedtls_internal_ecp_grp_capable(grp)) { + return mbedtls_internal_ecp_double_jac(grp, R, P); + } +#endif /* MBEDTLS_ECP_DOUBLE_JAC_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + /* Special case for A = -3 */ + if (grp->A.p == NULL) { + /* tmp[0] <- M = 3(X + Z^2)(X - Z^2) */ + MPI_ECP_SQR(&tmp[1], &P->Z); + MPI_ECP_ADD(&tmp[2], &P->X, &tmp[1]); + MPI_ECP_SUB(&tmp[3], &P->X, &tmp[1]); + MPI_ECP_MUL(&tmp[1], &tmp[2], &tmp[3]); + MPI_ECP_MUL_INT(&tmp[0], &tmp[1], 3); + } else { + /* tmp[0] <- M = 3.X^2 + A.Z^4 */ + MPI_ECP_SQR(&tmp[1], &P->X); + MPI_ECP_MUL_INT(&tmp[0], &tmp[1], 3); + + /* Optimize away for "koblitz" curves with A = 0 */ + if (MPI_ECP_CMP_INT(&grp->A, 0) != 0) { + /* M += A.Z^4 */ + MPI_ECP_SQR(&tmp[1], &P->Z); + MPI_ECP_SQR(&tmp[2], &tmp[1]); + MPI_ECP_MUL(&tmp[1], &tmp[2], &grp->A); + MPI_ECP_ADD(&tmp[0], &tmp[0], &tmp[1]); + } + } + + /* tmp[1] <- S = 4.X.Y^2 */ + MPI_ECP_SQR(&tmp[2], &P->Y); + MPI_ECP_SHIFT_L(&tmp[2], 1); + MPI_ECP_MUL(&tmp[1], &P->X, &tmp[2]); + MPI_ECP_SHIFT_L(&tmp[1], 1); + + /* tmp[3] <- U = 8.Y^4 */ + MPI_ECP_SQR(&tmp[3], &tmp[2]); + MPI_ECP_SHIFT_L(&tmp[3], 1); + + /* tmp[2] <- T = M^2 - 2.S */ + MPI_ECP_SQR(&tmp[2], &tmp[0]); + MPI_ECP_SUB(&tmp[2], &tmp[2], &tmp[1]); + MPI_ECP_SUB(&tmp[2], &tmp[2], &tmp[1]); + + /* tmp[1] <- S = M(S - T) - U */ + MPI_ECP_SUB(&tmp[1], &tmp[1], &tmp[2]); + MPI_ECP_MUL(&tmp[1], &tmp[1], &tmp[0]); + MPI_ECP_SUB(&tmp[1], &tmp[1], &tmp[3]); + + /* tmp[3] <- U = 2.Y.Z */ + MPI_ECP_MUL(&tmp[3], &P->Y, &P->Z); + MPI_ECP_SHIFT_L(&tmp[3], 1); + + /* Store results */ + MPI_ECP_MOV(&R->X, &tmp[2]); + MPI_ECP_MOV(&R->Y, &tmp[1]); + MPI_ECP_MOV(&R->Z, &tmp[3]); + +cleanup: + + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) */ +} + +/* + * Addition: R = P + Q, mixed affine-Jacobian coordinates (GECC 3.22) + * + * The coordinates of Q must be normalized (= affine), + * but those of P don't need to. R is not normalized. + * + * P,Q,R may alias, but only at the level of EC points: they must be either + * equal as pointers, or disjoint (including the coordinate data buffers). + * Fine-grained aliasing at the level of coordinates is not supported. + * + * Special cases: (1) P or Q is zero, (2) R is zero, (3) P == Q. + * None of these cases can happen as intermediate step in ecp_mul_comb(): + * - at each step, P, Q and R are multiples of the base point, the factor + * being less than its order, so none of them is zero; + * - Q is an odd multiple of the base point, P an even multiple, + * due to the choice of precomputed points in the modified comb method. + * So branches for these cases do not leak secret information. + * + * Cost: 1A := 8M + 3S + */ +static int ecp_add_mixed(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, + const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q, + mbedtls_mpi tmp[4]) +{ +#if defined(MBEDTLS_SELF_TEST) + add_count++; +#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); + } +#endif /* MBEDTLS_ECP_ADD_MIXED_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_ADD_MIXED_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + /* NOTE: Aliasing between input and output is allowed, so one has to make + * sure that at the point X,Y,Z are written, {P,Q}->{X,Y,Z} are no + * longer read from. */ + mbedtls_mpi * const X = &R->X; + mbedtls_mpi * const Y = &R->Y; + mbedtls_mpi * const Z = &R->Z; + + if (!MPI_ECP_VALID(&Q->Z)) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* + * Trivial cases: P == 0 or Q == 0 (case 1) + */ + if (MPI_ECP_CMP_INT(&P->Z, 0) == 0) { + return mbedtls_ecp_copy(R, Q); + } + + if (MPI_ECP_CMP_INT(&Q->Z, 0) == 0) { + return mbedtls_ecp_copy(R, P); + } + + /* + * Make sure Q coordinates are normalized + */ + if (MPI_ECP_CMP_INT(&Q->Z, 1) != 0) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + MPI_ECP_SQR(&tmp[0], &P->Z); + MPI_ECP_MUL(&tmp[1], &tmp[0], &P->Z); + MPI_ECP_MUL(&tmp[0], &tmp[0], &Q->X); + MPI_ECP_MUL(&tmp[1], &tmp[1], &Q->Y); + MPI_ECP_SUB(&tmp[0], &tmp[0], &P->X); + MPI_ECP_SUB(&tmp[1], &tmp[1], &P->Y); + + /* Special cases (2) and (3) */ + if (MPI_ECP_CMP_INT(&tmp[0], 0) == 0) { + if (MPI_ECP_CMP_INT(&tmp[1], 0) == 0) { + ret = ecp_double_jac(grp, R, P, tmp); + goto cleanup; + } else { + ret = mbedtls_ecp_set_zero(R); + goto cleanup; + } + } + + /* {P,Q}->Z no longer used, so OK to write to Z even if there's aliasing. */ + MPI_ECP_MUL(Z, &P->Z, &tmp[0]); + MPI_ECP_SQR(&tmp[2], &tmp[0]); + MPI_ECP_MUL(&tmp[3], &tmp[2], &tmp[0]); + MPI_ECP_MUL(&tmp[2], &tmp[2], &P->X); + + MPI_ECP_MOV(&tmp[0], &tmp[2]); + MPI_ECP_SHIFT_L(&tmp[0], 1); + + /* {P,Q}->X no longer used, so OK to write to X even if there's aliasing. */ + MPI_ECP_SQR(X, &tmp[1]); + MPI_ECP_SUB(X, X, &tmp[0]); + MPI_ECP_SUB(X, X, &tmp[3]); + MPI_ECP_SUB(&tmp[2], &tmp[2], X); + MPI_ECP_MUL(&tmp[2], &tmp[2], &tmp[1]); + MPI_ECP_MUL(&tmp[3], &tmp[3], &P->Y); + /* {P,Q}->Y no longer used, so OK to write to Y even if there's aliasing. */ + MPI_ECP_SUB(Y, &tmp[2], &tmp[3]); + +cleanup: + + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_ADD_MIXED_ALT) */ +} + +/* + * Randomize jacobian coordinates: + * (X, Y, Z) -> (l^2 X, l^3 Y, l Z) for random l + * This is sort of the reverse operation of ecp_normalize_jac(). + * + * This countermeasure was first suggested in [2]. + */ +static int ecp_randomize_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ +#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); + } +#endif /* MBEDTLS_ECP_RANDOMIZE_JAC_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi l; + + mbedtls_mpi_init(&l); + + /* Generate l such that 1 < l < p */ + MPI_ECP_RAND(&l); + + /* Z' = l * Z */ + MPI_ECP_MUL(&pt->Z, &pt->Z, &l); + + /* Y' = l * Y */ + MPI_ECP_MUL(&pt->Y, &pt->Y, &l); + + /* X' = l^2 * X */ + MPI_ECP_SQR(&l, &l); + MPI_ECP_MUL(&pt->X, &pt->X, &l); + + /* Y'' = l^2 * Y' = l^3 * Y */ + MPI_ECP_MUL(&pt->Y, &pt->Y, &l); + +cleanup: + mbedtls_mpi_free(&l); + + if (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) { + ret = MBEDTLS_ERR_ECP_RANDOM_FAILED; + } + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT) */ +} + +/* + * Check and define parameters used by the comb method (see below for details) + */ +#if MBEDTLS_ECP_WINDOW_SIZE < 2 || MBEDTLS_ECP_WINDOW_SIZE > 7 +#error "MBEDTLS_ECP_WINDOW_SIZE out of bounds" +#endif + +/* d = ceil( n / w ) */ +#define COMB_MAX_D (MBEDTLS_ECP_MAX_BITS + 1) / 2 + +/* number of precomputed points */ +#define COMB_MAX_PRE (1 << (MBEDTLS_ECP_WINDOW_SIZE - 1)) + +/* + * Compute the representation of m that will be used with our comb method. + * + * The basic comb method is described in GECC 3.44 for example. We use a + * 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, but saves on the size of + * the precomputed table. + * + * 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 + * - w is the size, ie number of teeth, of the comb, and must be between + * 2 and 7 (in practice, between 2 and MBEDTLS_ECP_WINDOW_SIZE) + * - 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_recode_core(unsigned char x[], size_t d, + unsigned char w, const mbedtls_mpi *m) +{ + size_t i, j; + unsigned char c, cc, adjust; + + memset(x, 0, d+1); + + /* First get the classical comb values (except for x_d = 0) */ + for (i = 0; i < d; i++) { + for (j = 0; j < w; j++) { + x[i] |= mbedtls_mpi_get_bit(m, i + d * j) << j; + } + } + + /* Now make sure x_1 .. x_d are odd */ + c = 0; + for (i = 1; i <= d; i++) { + /* Add carry and update it */ + cc = x[i] & c; + x[i] = x[i] ^ c; + c = cc; + + /* Adjust if needed, avoiding branches */ + adjust = 1 - (x[i] & 0x01); + c |= x[i] & (x[i-1] * adjust); + x[i] = x[i] ^ (x[i-1] * adjust); + x[i-1] |= adjust << 7; + } +} + +/* + * Precompute points for the adapted comb method + * + * Assumption: 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, + mbedtls_ecp_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char i; + size_t j = 0; + const unsigned char T_size = 1U << (w - 1); + mbedtls_ecp_point *cur, *TT[COMB_MAX_PRE - 1] = { NULL }; + + mbedtls_mpi tmp[4]; + + mpi_init_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + +#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)); + +#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; + + 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, tmp)); + } + +#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 to allow them to be used in + * ecp_add_mixed() below, which requires one normalized input. + * + * 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! + */ + 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], tmp)); + } + } + +#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)); + + /* Free Z coordinate (=1 after normalization) to save RAM. + * This makes T[i] invalid as mbedtls_ecp_points, but this is OK + * since from this point onwards, they are only accessed indirectly + * via the getter function ecp_select_comb() which does set the + * target's Z coordinate to 1. */ + for (i = 0; i < T_size; i++) { + mbedtls_mpi_free(&T[i].Z); + } + +cleanup: + + mpi_free_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + +#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_size, + unsigned char i) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char ii, j; + + /* Ignore the "sign" bit and scale down */ + ii = (i & 0x7Fu) >> 1; + + /* Read the whole table to thwart cache-based timing attacks */ + for (j = 0; j < T_size; j++) { + MPI_ECP_COND_ASSIGN(&R->X, &T[j].X, j == ii); + MPI_ECP_COND_ASSIGN(&R->Y, &T[j].Y, j == ii); + } + + /* Safely invert result if i is "negative" */ + MBEDTLS_MPI_CHK(ecp_safe_invert_jac(grp, R, i >> 7)); + + MPI_ECP_LSET(&R->Z, 1); + +cleanup: + return ret; +} + +/* + * Core multiplication algorithm for the (modified) comb method. + * This part is actually common with the basic comb method (GECC 3.44) + * + * 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_size, + const unsigned char x[], size_t d, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_ecp_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_ecp_point Txi; + mbedtls_mpi tmp[4]; + size_t i; + + mbedtls_ecp_point_init(&Txi); + mpi_init_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + +#if !defined(MBEDTLS_ECP_RESTARTABLE) + (void) rs_ctx; +#endif + +#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])); + 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, tmp)); + MBEDTLS_MPI_CHK(ecp_select_comb(grp, &Txi, T, T_size, x[i])); + MBEDTLS_MPI_CHK(ecp_add_mixed(grp, R, R, &Txi, tmp)); + } + +cleanup: + + mbedtls_ecp_point_free(&Txi); + mpi_free_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + +#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; +} + +/* + * 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_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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi M, mm; + + mbedtls_mpi_init(&M); + mbedtls_mpi_init(&mm); + + /* 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + 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: + MBEDTLS_ECP_BUDGET(MBEDTLS_ECP_OPS_INV); +#endif + /* + * Knowledge of the jacobian coordinates may leak the last few bits of the + * scalar [1], and since our MPI implementation isn't constant-flow, + * inversion (used for coordinate normalization) may leak the full value + * of its input via side-channels [2]. + * + * [1] https://eprint.iacr.org/2003/191 + * [2] https://eprint.iacr.org/2020/055 + * + * Avoid the leak by randomizing coordinates before we normalize them. + */ + if (f_rng != 0) { + MBEDTLS_MPI_CHK(ecp_randomize_jac(grp, RR, f_rng, p_rng)); + } + + 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 ) + * (see costs of the various parts, with 1S = 1M) + */ + w = grp->nbits >= 384 ? 5 : 4; + + /* + * If P == G, pre-compute a bit more, since this may be re-used later. + * Just adding one avoids upping the cost of the first mul too much, + * and the memory cost too. + */ + if (p_eq_g) { + w++; + } + + /* + * If static comb table may not be used (!p_eq_g) or static comb table does + * not exists, make sure w is within bounds. + * (The last test is useful only for very small curves in the test suite.) + * + * The user reduces MBEDTLS_ECP_WINDOW_SIZE does not changes the size of + * static comb table, because the size of static comb table is fixed when + * it is generated. + */ +#if (MBEDTLS_ECP_WINDOW_SIZE < 6) + if ((!p_eq_g || !ecp_group_is_static_comb_table(grp)) && w > MBEDTLS_ECP_WINDOW_SIZE) { + w = MBEDTLS_ECP_WINDOW_SIZE; + } +#endif + if (w >= grp->nbits) { + w = 2; + } + + 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 transfer, 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char w, p_eq_g, i; + size_t d; + unsigned char T_size = 0, T_ok = 0; + mbedtls_ecp_point *T = NULL; + + ECP_RS_ENTER(rsm); + + /* Is P the base point ? */ +#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1 + p_eq_g = (MPI_ECP_CMP(&P->Y, &grp->G.Y) == 0 && + MPI_ECP_CMP(&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; + + /* Pre-computed table: do we have it already for the base point? */ + if (p_eq_g && grp->T != NULL) { + /* 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; + } + + 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 = T_size; + } + } + + /* 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: + + /* 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) { + /* 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); + } + + /* prevent caller from using invalid value */ + int should_free_R = (ret != 0); +#if defined(MBEDTLS_ECP_RESTARTABLE) + /* don't free R while in progress in case R == P */ + if (ret == MBEDTLS_ERR_ECP_IN_PROGRESS) { + should_free_R = 0; + } +#endif + if (should_free_R) { + mbedtls_ecp_point_free(R); + } + + ECP_RS_LEAVE(rsm); + + return ret; +} + +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) +/* + * For Montgomery curves, we do all the internal arithmetic in projective + * coordinates. Import/export of points uses only the x coordinates, which is + * internally represented as X / Z. + * + * For scalar multiplication, we'll use a Montgomery ladder. + */ + +/* + * Normalize Montgomery x/z coordinates: X = X/Z, Z = 1 + * Cost: 1M + 1I + */ +static int ecp_normalize_mxz(const mbedtls_ecp_group *grp, mbedtls_ecp_point *P) +{ +#if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT) + if (mbedtls_internal_ecp_grp_capable(grp)) { + return mbedtls_internal_ecp_normalize_mxz(grp, P); + } +#endif /* MBEDTLS_ECP_NORMALIZE_MXZ_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MPI_ECP_INV(&P->Z, &P->Z); + MPI_ECP_MUL(&P->X, &P->X, &P->Z); + MPI_ECP_LSET(&P->Z, 1); + +cleanup: + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT) */ +} + +/* + * Randomize projective x/z coordinates: + * (X, Z) -> (l X, l Z) for random l + * This is sort of the reverse operation of ecp_normalize_mxz(). + * + * This countermeasure was first suggested in [2]. + * Cost: 2M + */ +static int ecp_randomize_mxz(const mbedtls_ecp_group *grp, mbedtls_ecp_point *P, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ +#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); + } +#endif /* MBEDTLS_ECP_RANDOMIZE_MXZ_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi l; + mbedtls_mpi_init(&l); + + /* Generate l such that 1 < l < p */ + MPI_ECP_RAND(&l); + + MPI_ECP_MUL(&P->X, &P->X, &l); + MPI_ECP_MUL(&P->Z, &P->Z, &l); + +cleanup: + mbedtls_mpi_free(&l); + + if (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) { + ret = MBEDTLS_ERR_ECP_RANDOM_FAILED; + } + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT) */ +} + +/* + * Double-and-add: R = 2P, S = P + Q, with d = X(P - Q), + * for Montgomery curves in x/z coordinates. + * + * http://www.hyperelliptic.org/EFD/g1p/auto-code/montgom/xz/ladder/mladd-1987-m.op3 + * with + * d = X1 + * P = (X2, Z2) + * Q = (X3, Z3) + * R = (X4, Z4) + * S = (X5, Z5) + * and eliminating temporary variables tO, ..., t4. + * + * Cost: 5M + 4S + */ +static int ecp_double_add_mxz(const mbedtls_ecp_group *grp, + mbedtls_ecp_point *R, mbedtls_ecp_point *S, + const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q, + const mbedtls_mpi *d, + mbedtls_mpi T[4]) +{ +#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); + } +#endif /* MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT */ + +#if defined(MBEDTLS_ECP_NO_FALLBACK) && defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT) + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; +#else + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MPI_ECP_ADD(&T[0], &P->X, &P->Z); /* Pp := PX + PZ */ + MPI_ECP_SUB(&T[1], &P->X, &P->Z); /* Pm := PX - PZ */ + MPI_ECP_ADD(&T[2], &Q->X, &Q->Z); /* Qp := QX + XZ */ + MPI_ECP_SUB(&T[3], &Q->X, &Q->Z); /* Qm := QX - QZ */ + MPI_ECP_MUL(&T[3], &T[3], &T[0]); /* Qm * Pp */ + MPI_ECP_MUL(&T[2], &T[2], &T[1]); /* Qp * Pm */ + MPI_ECP_SQR(&T[0], &T[0]); /* Pp^2 */ + MPI_ECP_SQR(&T[1], &T[1]); /* Pm^2 */ + MPI_ECP_MUL(&R->X, &T[0], &T[1]); /* Pp^2 * Pm^2 */ + MPI_ECP_SUB(&T[0], &T[0], &T[1]); /* Pp^2 - Pm^2 */ + MPI_ECP_MUL(&R->Z, &grp->A, &T[0]); /* A * (Pp^2 - Pm^2) */ + MPI_ECP_ADD(&R->Z, &T[1], &R->Z); /* [ A * (Pp^2-Pm^2) ] + Pm^2 */ + MPI_ECP_ADD(&S->X, &T[3], &T[2]); /* Qm*Pp + Qp*Pm */ + MPI_ECP_SQR(&S->X, &S->X); /* (Qm*Pp + Qp*Pm)^2 */ + MPI_ECP_SUB(&S->Z, &T[3], &T[2]); /* Qm*Pp - Qp*Pm */ + MPI_ECP_SQR(&S->Z, &S->Z); /* (Qm*Pp - Qp*Pm)^2 */ + MPI_ECP_MUL(&S->Z, d, &S->Z); /* d * ( Qm*Pp - Qp*Pm )^2 */ + MPI_ECP_MUL(&R->Z, &T[0], &R->Z); /* [A*(Pp^2-Pm^2)+Pm^2]*(Pp^2-Pm^2) */ + +cleanup: + + return ret; +#endif /* !defined(MBEDTLS_ECP_NO_FALLBACK) || !defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT) */ +} + +/* + * Multiplication with Montgomery ladder in x/z coordinates, + * for curves in Montgomery form + */ +static int ecp_mul_mxz(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 ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t i; + unsigned char b; + mbedtls_ecp_point RP; + mbedtls_mpi PX; + mbedtls_mpi tmp[4]; + mbedtls_ecp_point_init(&RP); mbedtls_mpi_init(&PX); + + mpi_init_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + + if (f_rng == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + /* Save PX and read from P before writing to R, in case P == R */ + MPI_ECP_MOV(&PX, &P->X); + MBEDTLS_MPI_CHK(mbedtls_ecp_copy(&RP, P)); + + /* Set R to zero in modified x/z coordinates */ + MPI_ECP_LSET(&R->X, 1); + MPI_ECP_LSET(&R->Z, 0); + mbedtls_mpi_free(&R->Y); + + /* RP.X might be slightly larger than P, so reduce it */ + MOD_ADD(&RP.X); + + /* Randomize coordinates of the starting point */ + MBEDTLS_MPI_CHK(ecp_randomize_mxz(grp, &RP, f_rng, p_rng)); + + /* Loop invariant: R = result so far, RP = R + P */ + i = grp->nbits + 1; /* one past the (zero-based) required msb for private keys */ + while (i-- > 0) { + b = mbedtls_mpi_get_bit(m, i); + /* + * if (b) R = 2R + P else R = 2R, + * which is: + * if (b) double_add( RP, R, RP, R ) + * else double_add( R, RP, R, RP ) + * but using safe conditional swaps to avoid leaks + */ + MPI_ECP_COND_SWAP(&R->X, &RP.X, b); + MPI_ECP_COND_SWAP(&R->Z, &RP.Z, b); + MBEDTLS_MPI_CHK(ecp_double_add_mxz(grp, R, &RP, R, &RP, &PX, tmp)); + MPI_ECP_COND_SWAP(&R->X, &RP.X, b); + MPI_ECP_COND_SWAP(&R->Z, &RP.Z, b); + } + + /* + * Knowledge of the projective coordinates may leak the last few bits of the + * scalar [1], and since our MPI implementation isn't constant-flow, + * inversion (used for coordinate normalization) may leak the full value + * of its input via side-channels [2]. + * + * [1] https://eprint.iacr.org/2003/191 + * [2] https://eprint.iacr.org/2020/055 + * + * Avoid the leak by randomizing coordinates before we normalize them. + */ + MBEDTLS_MPI_CHK(ecp_randomize_mxz(grp, R, f_rng, p_rng)); + MBEDTLS_MPI_CHK(ecp_normalize_mxz(grp, R)); + +cleanup: + mbedtls_ecp_point_free(&RP); mbedtls_mpi_free(&PX); + + mpi_free_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + return ret; +} + +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + +/* + * Restartable multiplication R = m * P + * + * This internal function can be called without an RNG in case where we know + * the inputs are not sensitive. + */ +static int ecp_mul_restartable_internal(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 = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + char is_grp_capable = 0; +#endif + +#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; + } +#else + (void) rs_ctx; +#endif + +#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 */ + + int restarting = 0; +#if defined(MBEDTLS_ECP_RESTARTABLE) + restarting = (rs_ctx != NULL && rs_ctx->rsm != NULL); +#endif + /* skip argument check when restarting */ + if (!restarting) { + /* 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)); + } + + ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + MBEDTLS_MPI_CHK(ecp_mul_mxz(grp, R, m, P, f_rng, p_rng)); + } +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + MBEDTLS_MPI_CHK(ecp_mul_comb(grp, R, m, P, f_rng, p_rng, rs_ctx)); + } +#endif + +cleanup: + +#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; +} + +/* + * Restartable multiplication R = m * P + */ +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, + mbedtls_ecp_restart_ctx *rs_ctx) +{ + if (f_rng == NULL) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + return ecp_mul_restartable_internal(grp, R, m, P, f_rng, p_rng, rs_ctx); +} + +/* + * 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); +} +#endif /* MBEDTLS_ECP_C */ + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) +/* + * Check that an affine point is valid as a public key, + * short weierstrass curves (SEC1 3.2.3.1) + */ +static int ecp_check_pubkey_sw(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi YY, RHS; + + /* pt coordinates must be normalized for our checks */ + if (mbedtls_mpi_cmp_int(&pt->X, 0) < 0 || + mbedtls_mpi_cmp_int(&pt->Y, 0) < 0 || + mbedtls_mpi_cmp_mpi(&pt->X, &grp->P) >= 0 || + mbedtls_mpi_cmp_mpi(&pt->Y, &grp->P) >= 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + mbedtls_mpi_init(&YY); mbedtls_mpi_init(&RHS); + + /* + * YY = Y^2 + * RHS = X^3 + A X + B + */ + MPI_ECP_SQR(&YY, &pt->Y); + MBEDTLS_MPI_CHK(ecp_sw_rhs(grp, &RHS, &pt->X)); + + if (MPI_ECP_CMP(&YY, &RHS) != 0) { + ret = MBEDTLS_ERR_ECP_INVALID_KEY; + } + +cleanup: + + mbedtls_mpi_free(&YY); mbedtls_mpi_free(&RHS); + + return ret; +} +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +#if defined(MBEDTLS_ECP_C) +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) +/* + * R = m * P with shortcuts for m == 0, m == 1 and m == -1 + * NOT constant-time - ONLY for short Weierstrass! + */ +static int mbedtls_ecp_mul_shortcuts(mbedtls_ecp_group *grp, + mbedtls_ecp_point *R, + const mbedtls_mpi *m, + const mbedtls_ecp_point *P, + mbedtls_ecp_restart_ctx *rs_ctx) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi tmp; + mbedtls_mpi_init(&tmp); + + if (mbedtls_mpi_cmp_int(m, 0) == 0) { + MBEDTLS_MPI_CHK(mbedtls_ecp_check_pubkey(grp, P)); + MBEDTLS_MPI_CHK(mbedtls_ecp_set_zero(R)); + } else if (mbedtls_mpi_cmp_int(m, 1) == 0) { + MBEDTLS_MPI_CHK(mbedtls_ecp_check_pubkey(grp, P)); + MBEDTLS_MPI_CHK(mbedtls_ecp_copy(R, P)); + } else if (mbedtls_mpi_cmp_int(m, -1) == 0) { + MBEDTLS_MPI_CHK(mbedtls_ecp_check_pubkey(grp, P)); + MBEDTLS_MPI_CHK(mbedtls_ecp_copy(R, P)); + MPI_ECP_NEG(&R->Y); + } else { + MBEDTLS_MPI_CHK(ecp_mul_restartable_internal(grp, R, m, P, + NULL, NULL, rs_ctx)); + } + +cleanup: + mbedtls_mpi_free(&tmp); + + 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_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_ecp_point mP; + mbedtls_ecp_point *pmP = &mP; + mbedtls_ecp_point *pR = R; + mbedtls_mpi tmp[4]; +#if defined(MBEDTLS_ECP_INTERNAL_ALT) + char is_grp_capable = 0; +#endif + if (mbedtls_ecp_get_type(grp) != MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + } + + mbedtls_ecp_point_init(&mP); + mpi_init_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + + 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_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 */ + +#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, tmp)); +#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: + + mpi_free_many(tmp, sizeof(tmp) / sizeof(mbedtls_mpi)); + +#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 + */ +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) +{ + return mbedtls_ecp_muladd_restartable(grp, R, m, P, n, Q, NULL); +} +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ +#endif /* MBEDTLS_ECP_C */ + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) +#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) +#define ECP_MPI_INIT(s, n, p) { s, (n), (mbedtls_mpi_uint *) (p) } +#define ECP_MPI_INIT_ARRAY(x) \ + ECP_MPI_INIT(1, sizeof(x) / sizeof(mbedtls_mpi_uint), x) +/* + * Constants for the two points other than 0, 1, -1 (mod p) in + * https://cr.yp.to/ecdh.html#validate + * See ecp_check_pubkey_x25519(). + */ +static const mbedtls_mpi_uint x25519_bad_point_1[] = { + MBEDTLS_BYTES_TO_T_UINT_8(0xe0, 0xeb, 0x7a, 0x7c, 0x3b, 0x41, 0xb8, 0xae), + MBEDTLS_BYTES_TO_T_UINT_8(0x16, 0x56, 0xe3, 0xfa, 0xf1, 0x9f, 0xc4, 0x6a), + MBEDTLS_BYTES_TO_T_UINT_8(0xda, 0x09, 0x8d, 0xeb, 0x9c, 0x32, 0xb1, 0xfd), + MBEDTLS_BYTES_TO_T_UINT_8(0x86, 0x62, 0x05, 0x16, 0x5f, 0x49, 0xb8, 0x00), +}; +static const mbedtls_mpi_uint x25519_bad_point_2[] = { + MBEDTLS_BYTES_TO_T_UINT_8(0x5f, 0x9c, 0x95, 0xbc, 0xa3, 0x50, 0x8c, 0x24), + MBEDTLS_BYTES_TO_T_UINT_8(0xb1, 0xd0, 0xb1, 0x55, 0x9c, 0x83, 0xef, 0x5b), + MBEDTLS_BYTES_TO_T_UINT_8(0x04, 0x44, 0x5c, 0xc4, 0x58, 0x1c, 0x8e, 0x86), + MBEDTLS_BYTES_TO_T_UINT_8(0xd8, 0x22, 0x4e, 0xdd, 0xd0, 0x9f, 0x11, 0x57), +}; +static const mbedtls_mpi ecp_x25519_bad_point_1 = ECP_MPI_INIT_ARRAY( + x25519_bad_point_1); +static const mbedtls_mpi ecp_x25519_bad_point_2 = ECP_MPI_INIT_ARRAY( + x25519_bad_point_2); +#endif /* MBEDTLS_ECP_DP_CURVE25519_ENABLED */ + +/* + * Check that the input point is not one of the low-order points. + * This is recommended by the "May the Fourth" paper: + * https://eprint.iacr.org/2017/806.pdf + * Those points are never sent by an honest peer. + */ +static int ecp_check_bad_points_mx(const mbedtls_mpi *X, const mbedtls_mpi *P, + const mbedtls_ecp_group_id grp_id) +{ + int ret; + mbedtls_mpi XmP; + + mbedtls_mpi_init(&XmP); + + /* Reduce X mod P so that we only need to check values less than P. + * We know X < 2^256 so we can proceed by subtraction. */ + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&XmP, X)); + while (mbedtls_mpi_cmp_mpi(&XmP, P) >= 0) { + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&XmP, &XmP, P)); + } + + /* Check against the known bad values that are less than P. For Curve448 + * these are 0, 1 and -1. For Curve25519 we check the values less than P + * from the following list: https://cr.yp.to/ecdh.html#validate */ + if (mbedtls_mpi_cmp_int(&XmP, 1) <= 0) { /* takes care of 0 and 1 */ + ret = MBEDTLS_ERR_ECP_INVALID_KEY; + goto cleanup; + } + +#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) + if (grp_id == MBEDTLS_ECP_DP_CURVE25519) { + if (mbedtls_mpi_cmp_mpi(&XmP, &ecp_x25519_bad_point_1) == 0) { + ret = MBEDTLS_ERR_ECP_INVALID_KEY; + goto cleanup; + } + + if (mbedtls_mpi_cmp_mpi(&XmP, &ecp_x25519_bad_point_2) == 0) { + ret = MBEDTLS_ERR_ECP_INVALID_KEY; + goto cleanup; + } + } +#else + (void) grp_id; +#endif + + /* Final check: check if XmP + 1 is P (final because it changes XmP!) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&XmP, &XmP, 1)); + if (mbedtls_mpi_cmp_mpi(&XmP, P) == 0) { + ret = MBEDTLS_ERR_ECP_INVALID_KEY; + goto cleanup; + } + + ret = 0; + +cleanup: + mbedtls_mpi_free(&XmP); + + return ret; +} + +/* + * Check validity of a public key for Montgomery curves with x-only schemes + */ +static int ecp_check_pubkey_mx(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt) +{ + /* [Curve25519 p. 5] Just check X is the correct number of bytes */ + /* Allow any public value, if it's too big then we'll just reduce it mod p + * (RFC 7748 sec. 5 para. 3). */ + if (mbedtls_mpi_size(&pt->X) > (grp->nbits + 7) / 8) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + /* Implicit in all standards (as they don't consider negative numbers): + * X must be non-negative. This is normally ensured by the way it's + * encoded for transmission, but let's be extra sure. */ + if (mbedtls_mpi_cmp_int(&pt->X, 0) < 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + return ecp_check_bad_points_mx(&pt->X, &grp->P, grp->id); +} +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + +/* + * Check that a point is valid as a public key + */ +int mbedtls_ecp_check_pubkey(const mbedtls_ecp_group *grp, + const mbedtls_ecp_point *pt) +{ + /* Must use affine coordinates */ + if (mbedtls_mpi_cmp_int(&pt->Z, 1) != 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + return ecp_check_pubkey_mx(grp, pt); + } +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + return ecp_check_pubkey_sw(grp, pt); + } +#endif + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +} + +/* + * Check that an mbedtls_mpi is valid as a private key + */ +int mbedtls_ecp_check_privkey(const mbedtls_ecp_group *grp, + const mbedtls_mpi *d) +{ +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + /* see RFC 7748 sec. 5 para. 5 */ + if (mbedtls_mpi_get_bit(d, 0) != 0 || + 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; + } + + /* see [Curve25519] page 5 */ + if (grp->nbits == 254 && mbedtls_mpi_get_bit(d, 2) != 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + return 0; + } +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + /* see SEC1 3.2 */ + if (mbedtls_mpi_cmp_int(d, 1) < 0 || + mbedtls_mpi_cmp_mpi(d, &grp->N) >= 0) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } else { + return 0; + } + } +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +} + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) +MBEDTLS_STATIC_TESTABLE +int mbedtls_ecp_gen_privkey_mx(size_t high_bit, + mbedtls_mpi *d, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng) +{ + int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + size_t n_random_bytes = high_bit / 8 + 1; + + /* [Curve25519] page 5 */ + /* Generate a (high_bit+1)-bit random number by generating just enough + * random bytes, then shifting out extra bits from the top (necessary + * when (high_bit+1) is not a multiple of 8). */ + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(d, n_random_bytes, + f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_shift_r(d, 8 * n_random_bytes - high_bit - 1)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(d, high_bit, 1)); + + /* Make sure the last two bits are unset for Curve448, three bits for + Curve25519 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(d, 0, 0)); + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(d, 1, 0)); + if (high_bit == 254) { + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(d, 2, 0)); + } + +cleanup: + return ret; +} +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) +static int mbedtls_ecp_gen_privkey_sw( + const mbedtls_mpi *N, mbedtls_mpi *d, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + int ret = mbedtls_mpi_random(d, 1, N, f_rng, p_rng); + switch (ret) { + case MBEDTLS_ERR_MPI_NOT_ACCEPTABLE: + return MBEDTLS_ERR_ECP_RANDOM_FAILED; + default: + return ret; + } +} +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +/* + * Generate a private key + */ +int mbedtls_ecp_gen_privkey(const mbedtls_ecp_group *grp, + mbedtls_mpi *d, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng) +{ +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + return mbedtls_ecp_gen_privkey_mx(grp->nbits, d, f_rng, p_rng); + } +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + return mbedtls_ecp_gen_privkey_sw(&grp->N, d, f_rng, p_rng); + } +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; +} + +#if defined(MBEDTLS_ECP_C) +/* + * 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + 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; +} + +/* + * Generate key pair, wrapper for conventional base point + */ +int mbedtls_ecp_gen_keypair(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_base(grp, &grp->G, d, Q, f_rng, p_rng); +} + +/* + * Generate a keypair, prettier wrapper + */ +int mbedtls_ecp_gen_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + if ((ret = mbedtls_ecp_group_load(&key->grp, grp_id)) != 0) { + return ret; + } + + return mbedtls_ecp_gen_keypair(&key->grp, &key->d, &key->Q, f_rng, p_rng); +} +#endif /* MBEDTLS_ECP_C */ + +#define ECP_CURVE25519_KEY_SIZE 32 +#define ECP_CURVE448_KEY_SIZE 56 +/* + * Read a private key. + */ +int mbedtls_ecp_read_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, + const unsigned char *buf, size_t buflen) +{ + int ret = 0; + + if ((ret = mbedtls_ecp_group_load(&key->grp, grp_id)) != 0) { + return ret; + } + + ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(&key->grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + /* + * Mask the key as mandated by RFC7748 for Curve25519 and Curve448. + */ + if (grp_id == MBEDTLS_ECP_DP_CURVE25519) { + if (buflen != ECP_CURVE25519_KEY_SIZE) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary_le(&key->d, buf, buflen)); + + /* Set the three least significant bits to 0 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&key->d, 0, 0)); + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&key->d, 1, 0)); + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&key->d, 2, 0)); + + /* Set the most significant bit to 0 */ + MBEDTLS_MPI_CHK( + mbedtls_mpi_set_bit(&key->d, + ECP_CURVE25519_KEY_SIZE * 8 - 1, 0) + ); + + /* Set the second most significant bit to 1 */ + MBEDTLS_MPI_CHK( + mbedtls_mpi_set_bit(&key->d, + ECP_CURVE25519_KEY_SIZE * 8 - 2, 1) + ); + } else if (grp_id == MBEDTLS_ECP_DP_CURVE448) { + if (buflen != ECP_CURVE448_KEY_SIZE) { + return MBEDTLS_ERR_ECP_INVALID_KEY; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary_le(&key->d, buf, buflen)); + + /* Set the two least significant bits to 0 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&key->d, 0, 0)); + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(&key->d, 1, 0)); + + /* Set the most significant bit to 1 */ + MBEDTLS_MPI_CHK( + mbedtls_mpi_set_bit(&key->d, + ECP_CURVE448_KEY_SIZE * 8 - 1, 1) + ); + } + } + +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(&key->grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&key->d, buf, buflen)); + + MBEDTLS_MPI_CHK(mbedtls_ecp_check_privkey(&key->grp, &key->d)); + } + +#endif +cleanup: + + if (ret != 0) { + mbedtls_mpi_free(&key->d); + } + + return ret; +} + +/* + * Write a private key. + */ +int mbedtls_ecp_write_key(mbedtls_ecp_keypair *key, + unsigned char *buf, size_t buflen) +{ + int ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE; + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (mbedtls_ecp_get_type(&key->grp) == MBEDTLS_ECP_TYPE_MONTGOMERY) { + if (key->grp.id == MBEDTLS_ECP_DP_CURVE25519) { + if (buflen < ECP_CURVE25519_KEY_SIZE) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + + } else if (key->grp.id == MBEDTLS_ECP_DP_CURVE448) { + if (buflen < ECP_CURVE448_KEY_SIZE) { + return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL; + } + } + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary_le(&key->d, buf, buflen)); + } +#endif +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + if (mbedtls_ecp_get_type(&key->grp) == MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&key->d, buf, buflen)); + } + +#endif +cleanup: + + return ret; +} + +#if defined(MBEDTLS_ECP_C) +/* + * Check a public-private key pair + */ +int mbedtls_ecp_check_pub_priv( + const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_ecp_point Q; + mbedtls_ecp_group grp; + if (pub->grp.id == MBEDTLS_ECP_DP_NONE || + pub->grp.id != prv->grp.id || + mbedtls_mpi_cmp_mpi(&pub->Q.X, &prv->Q.X) || + mbedtls_mpi_cmp_mpi(&pub->Q.Y, &prv->Q.Y) || + mbedtls_mpi_cmp_mpi(&pub->Q.Z, &prv->Q.Z)) { + return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + } + + mbedtls_ecp_point_init(&Q); + mbedtls_ecp_group_init(&grp); + + /* mbedtls_ecp_mul() needs a non-const group... */ + mbedtls_ecp_group_copy(&grp, &prv->grp); + + /* Also checks d is valid */ + MBEDTLS_MPI_CHK(mbedtls_ecp_mul(&grp, &Q, &prv->d, &prv->grp.G, f_rng, p_rng)); + + if (mbedtls_mpi_cmp_mpi(&Q.X, &prv->Q.X) || + mbedtls_mpi_cmp_mpi(&Q.Y, &prv->Q.Y) || + mbedtls_mpi_cmp_mpi(&Q.Z, &prv->Q.Z)) { + ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; + goto cleanup; + } + +cleanup: + mbedtls_ecp_point_free(&Q); + mbedtls_ecp_group_free(&grp); + + return ret; +} +#endif /* MBEDTLS_ECP_C */ + +/* + * Export generic key-pair parameters. + */ +int mbedtls_ecp_export(const mbedtls_ecp_keypair *key, mbedtls_ecp_group *grp, + mbedtls_mpi *d, mbedtls_ecp_point *Q) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if ((ret = mbedtls_ecp_group_copy(grp, &key->grp)) != 0) { + return ret; + } + + if ((ret = mbedtls_mpi_copy(d, &key->d)) != 0) { + return ret; + } + + if ((ret = mbedtls_ecp_copy(Q, &key->Q)) != 0) { + return ret; + } + + return 0; +} + +#if defined(MBEDTLS_SELF_TEST) + +#if defined(MBEDTLS_ECP_C) +/* + * PRNG for test - !!!INSECURE NEVER USE IN PRODUCTION!!! + * + * This is the linear congruential generator from numerical recipes, + * except we only use the low byte as the output. See + * https://en.wikipedia.org/wiki/Linear_congruential_generator#Parameters_in_common_use + */ +static int self_test_rng(void *ctx, unsigned char *out, size_t len) +{ + static uint32_t state = 42; + + (void) ctx; + + for (size_t i = 0; i < len; i++) { + state = state * 1664525u + 1013904223u; + out[i] = (unsigned char) state; + } + + return 0; +} + +/* Adjust the exponent to be a valid private point for the specified curve. + * This is sometimes necessary because we use a single set of exponents + * for all curves but the validity of values depends on the curve. */ +static int self_test_adjust_exponent(const mbedtls_ecp_group *grp, + mbedtls_mpi *m) +{ + int ret = 0; + switch (grp->id) { + /* If Curve25519 is available, then that's what we use for the + * Montgomery test, so we don't need the adjustment code. */ +#if !defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) +#if defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) + case MBEDTLS_ECP_DP_CURVE448: + /* Move highest bit from 254 to N-1. Setting bit N-1 is + * necessary to enforce the highest-bit-set constraint. */ + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(m, 254, 0)); + MBEDTLS_MPI_CHK(mbedtls_mpi_set_bit(m, grp->nbits, 1)); + /* Copy second-highest bit from 253 to N-2. This is not + * necessary but improves the test variety a bit. */ + MBEDTLS_MPI_CHK( + mbedtls_mpi_set_bit(m, grp->nbits - 1, + mbedtls_mpi_get_bit(m, 253))); + break; +#endif +#endif /* ! defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) */ + default: + /* Non-Montgomery curves and Curve25519 need no adjustment. */ + (void) grp; + (void) m; + goto cleanup; + } +cleanup: + return ret; +} + +/* Calculate R = m.P for each m in exponents. Check that the number of + * basic operations doesn't depend on the value of m. */ +static int self_test_point(int verbose, + mbedtls_ecp_group *grp, + mbedtls_ecp_point *R, + mbedtls_mpi *m, + const mbedtls_ecp_point *P, + const char *const *exponents, + size_t n_exponents) +{ + int ret = 0; + size_t i = 0; + unsigned long add_c_prev, dbl_c_prev, mul_c_prev; + add_count = 0; + dbl_count = 0; + mul_count = 0; + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(m, 16, exponents[0])); + MBEDTLS_MPI_CHK(self_test_adjust_exponent(grp, m)); + MBEDTLS_MPI_CHK(mbedtls_ecp_mul(grp, R, m, P, self_test_rng, NULL)); + + for (i = 1; i < n_exponents; 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(self_test_adjust_exponent(grp, m)); + MBEDTLS_MPI_CHK(mbedtls_ecp_mul(grp, R, m, P, self_test_rng, NULL)); + + if (add_count != add_c_prev || + dbl_count != dbl_c_prev || + mul_count != mul_c_prev) { + ret = 1; + break; + } + } + +cleanup: + if (verbose != 0) { + if (ret != 0) { + mbedtls_printf("failed (%u)\n", (unsigned int) i); + } else { + mbedtls_printf("passed\n"); + } + } + return ret; +} +#endif /* MBEDTLS_ECP_C */ + +/* + * Checkup routine + */ +int mbedtls_ecp_self_test(int verbose) +{ +#if defined(MBEDTLS_ECP_C) + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_ecp_group grp; + mbedtls_ecp_point R, P; + mbedtls_mpi m; + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + /* Exponents especially adapted for secp192k1, which has the lowest + * order n of all supported curves (secp192r1 is in a slightly larger + * field but the order of its base point is slightly smaller). */ + const char *sw_exponents[] = + { + "000000000000000000000000000000000000000000000001", /* one */ + "FFFFFFFFFFFFFFFFFFFFFFFE26F2FC170F69466A74DEFD8C", /* n - 1 */ + "5EA6F389A38B8BC81E767753B15AA5569E1782E30ABE7D25", /* random */ + "400000000000000000000000000000000000000000000000", /* one and zeros */ + "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", /* all ones */ + "555555555555555555555555555555555555555555555555", /* 101010... */ + }; +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + const char *m_exponents[] = + { + /* Valid private values for Curve25519. In a build with Curve448 + * but not Curve25519, they will be adjusted in + * self_test_adjust_exponent(). */ + "4000000000000000000000000000000000000000000000000000000000000000", + "5C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C3C30", + "5715ECCE24583F7A7023C24164390586842E816D7280A49EF6DF4EAE6B280BF8", + "41A2B017516F6D254E1F002BCCBADD54BE30F8CEC737A0E912B4963B6BA74460", + "5555555555555555555555555555555555555555555555555555555555555550", + "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF8", + }; +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + + mbedtls_ecp_group_init(&grp); + mbedtls_ecp_point_init(&R); + mbedtls_ecp_point_init(&P); + mbedtls_mpi_init(&m); + +#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) + /* 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 SW 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, self_test_rng, NULL)); + ret = self_test_point(verbose, + &grp, &R, &m, &grp.G, + sw_exponents, + sizeof(sw_exponents) / sizeof(sw_exponents[0])); + if (ret != 0) { + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf(" ECP SW test #2 (constant op_count, other point): "); + } + /* We computed P = 2G last time, use it */ + ret = self_test_point(verbose, + &grp, &R, &m, &P, + sw_exponents, + sizeof(sw_exponents) / sizeof(sw_exponents[0])); + if (ret != 0) { + goto cleanup; + } + + mbedtls_ecp_group_free(&grp); + mbedtls_ecp_point_free(&R); +#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ + +#if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) + if (verbose != 0) { + mbedtls_printf(" ECP Montgomery test (constant op_count): "); + } +#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) + MBEDTLS_MPI_CHK(mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_CURVE25519)); +#elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) + MBEDTLS_MPI_CHK(mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_CURVE448)); +#else +#error "MBEDTLS_ECP_MONTGOMERY_ENABLED is defined, but no curve is supported for self-test" +#endif + ret = self_test_point(verbose, + &grp, &R, &m, &grp.G, + m_exponents, + sizeof(m_exponents) / sizeof(m_exponents[0])); + if (ret != 0) { + goto cleanup; + } +#endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ + +cleanup: + + if (ret < 0 && verbose != 0) { + mbedtls_printf("Unexpected error, return code = %08X\n", (unsigned int) 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; +#else /* MBEDTLS_ECP_C */ + (void) verbose; + return 0; +#endif /* MBEDTLS_ECP_C */ +} + +#endif /* MBEDTLS_SELF_TEST */ + +MBEDTLS_STATIC_TESTABLE +mbedtls_ecp_variant mbedtls_ecp_get_variant() +{ + return MBEDTLS_ECP_VARIANT_WITH_MPI_UINT; +} + +#endif /* !MBEDTLS_ECP_ALT */ + +#endif /* MBEDTLS_ECP_LIGHT */ + +#endif /* MBEDTLS_ECP_WITH_MPI_UINT */ From 1df4c6435f6ec04deb468fb7497b0e55d2155783 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Tue, 6 Jun 2023 17:18:03 +0200 Subject: [PATCH 02/11] Enable build of the new ecp_new.c file Signed-off-by: Gabor Mezei --- library/CMakeLists.txt | 1 + library/Makefile | 1 + 2 files changed, 2 insertions(+) diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt index 8e70c4635..6fa21fa70 100644 --- a/library/CMakeLists.txt +++ b/library/CMakeLists.txt @@ -37,6 +37,7 @@ set(src_crypto ecdsa.c ecjpake.c ecp.c + ecp_new.c ecp_curves.c entropy.c entropy_poll.c diff --git a/library/Makefile b/library/Makefile index fafcdda8f..766343ac8 100644 --- a/library/Makefile +++ b/library/Makefile @@ -102,6 +102,7 @@ OBJS_CRYPTO= \ ecdsa.o \ ecjpake.o \ ecp.o \ + ecp_new.o \ ecp_curves.o \ entropy.o \ entropy_poll.o \ From 9b6b5a06d58fb16299ed7ec7bc3023115ea70f8e Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Tue, 6 Jun 2023 17:22:25 +0200 Subject: [PATCH 03/11] Enable testing the cloned ecp module Signed-off-by: Gabor Mezei --- tests/scripts/all.sh | 57 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh index 45f7e982f..d2ea9b68f 100755 --- a/tests/scripts/all.sh +++ b/tests/scripts/all.sh @@ -1026,6 +1026,27 @@ component_test_default_cmake_gcc_asan () { tests/context-info.sh } +component_test_default_cmake_gcc_asan_new_bignum () { + msg "build: cmake, gcc, ASan" # ~ 1 min 50s + CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan . + make CFLAGS="-D MBEDTLS_ECP_WITH_MPI_UINT" + + msg "test: main suites (inc. selftests) (ASan build)" # ~ 50s + make test + + msg "test: selftest (ASan build)" # ~ 10s + programs/test/selftest + + msg "test: ssl-opt.sh (ASan build)" # ~ 1 min + tests/ssl-opt.sh + + msg "test: compat.sh (ASan build)" # ~ 6 min + tests/compat.sh + + msg "test: context-info.sh (ASan build)" # ~ 15 sec + tests/context-info.sh +} + component_test_full_cmake_gcc_asan () { msg "build: full config, cmake, gcc, ASan" scripts/config.py full @@ -1061,6 +1082,42 @@ component_test_full_cmake_gcc_asan () { full-libmbedx509-modules } + +component_test_full_cmake_gcc_asan_new_bignum () { + msg "build: full config, cmake, gcc, ASan" + scripts/config.py full + CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan . + make CFLAGS="-D MBEDTLS_ECP_WITH_MPI_UINT" + + msg "test: main suites (inc. selftests) (full config, ASan build)" + make test + + msg "test: selftest (ASan build)" # ~ 10s + programs/test/selftest + + msg "test: ssl-opt.sh (full config, ASan build)" + tests/ssl-opt.sh + + msg "test: compat.sh (full config, ASan build)" + tests/compat.sh + + msg "test: context-info.sh (full config, ASan build)" # ~ 15 sec + tests/context-info.sh + + msg "test: check direct ECP dependencies in TLS and X.509" + docs/architecture/psa-migration/syms.sh full + + # TODO: replace "mbedtls_ecp_curve" with "mbedtls_ecp" also for + # "full-tls-external" once Issue6839 is completed + not grep mbedtls_ecp_curve full-libmbedtls-external + not grep mbedtls_ecp full-libmbedx509-external + + rm full-libmbedtls-external \ + full-libmbedtls-modules \ + full-libmbedx509-external \ + full-libmbedx509-modules +} + component_test_psa_crypto_key_id_encodes_owner () { msg "build: full config + PSA_CRYPTO_KEY_ID_ENCODES_OWNER, cmake, gcc, ASan" scripts/config.py full From c8107079801381c339fc3f850ae3d5edb1072840 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Tue, 6 Jun 2023 17:24:35 +0200 Subject: [PATCH 04/11] Add check for the ecp module variants Signed-off-by: Gabor Mezei --- library/ecp.c | 10 ++++++++++ library/ecp_invasive.h | 13 +++++++++++++ library/ecp_new.c | 4 ++++ tests/suites/test_suite_ecp.data | 3 +++ tests/suites/test_suite_ecp.function | 15 +++++++++++++++ 5 files changed, 45 insertions(+) diff --git a/library/ecp.c b/library/ecp.c index 1d690d1ad..60872567f 100644 --- a/library/ecp.c +++ b/library/ecp.c @@ -3639,6 +3639,16 @@ cleanup: #endif /* MBEDTLS_SELF_TEST */ +#if defined(MBEDTLS_TEST_HOOKS) + +MBEDTLS_STATIC_TESTABLE +mbedtls_ecp_variant mbedtls_ecp_get_variant() +{ + return MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT; +} + +#endif /* MBEDTLS_TEST_HOOKS */ + #endif /* !MBEDTLS_ECP_ALT */ #endif /* MBEDTLS_ECP_LIGHT */ diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 0ea02e285..0a0d361d2 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -48,8 +48,21 @@ typedef enum { #define MBEDTLS_ECP_WITH_MPI_STRUCT #endif +typedef enum { + MBEDTLS_ECP_VARIANT_NONE = 0, + MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT = 1, + MBEDTLS_ECP_VARIANT_WITH_MPI_UINT = 2 +} mbedtls_ecp_variant; + #if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_ECP_LIGHT) +/** Queries the ecp variant. + * + * \return The id of the ecp variant. + */ +MBEDTLS_STATIC_TESTABLE +mbedtls_ecp_variant mbedtls_ecp_get_variant(void); + #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) /** Generate a private key on a Montgomery curve (Curve25519 or Curve448). * diff --git a/library/ecp_new.c b/library/ecp_new.c index c212f6323..3df6f9f9c 100644 --- a/library/ecp_new.c +++ b/library/ecp_new.c @@ -3639,12 +3639,16 @@ cleanup: #endif /* MBEDTLS_SELF_TEST */ +#if defined(MBEDTLS_TEST_HOOKS) + MBEDTLS_STATIC_TESTABLE mbedtls_ecp_variant mbedtls_ecp_get_variant() { return MBEDTLS_ECP_VARIANT_WITH_MPI_UINT; } +#endif /* MBEDTLS_TEST_HOOKS */ + #endif /* !MBEDTLS_ECP_ALT */ #endif /* MBEDTLS_ECP_LIGHT */ diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data index 1560c5494..f10e572ef 100644 --- a/tests/suites/test_suite_ecp.data +++ b/tests/suites/test_suite_ecp.data @@ -1953,3 +1953,6 @@ ecp_mod_random:MBEDTLS_ECP_DP_SECP256K1:MBEDTLS_ECP_MOD_SCALAR ecp_random #25 MBEDTLS_ECP_MOD_COORDINATE(MBEDTLS_ECP_DP_CURVE448) depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED ecp_mod_random:MBEDTLS_ECP_DP_CURVE448:MBEDTLS_ECP_MOD_COORDINATE + +ecp variant check +check_variant: diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function index 2658a432a..03bbab68f 100644 --- a/tests/suites/test_suite_ecp.function +++ b/tests/suites/test_suite_ecp.function @@ -1630,3 +1630,18 @@ exit: mbedtls_free(rX_raw); } /* END_CASE */ + +/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */ +void check_variant() +{ + mbedtls_ecp_variant variant = mbedtls_ecp_get_variant(); + +#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT) + TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT); +#elif defined(MBEDTLS_ECP_WITH_MPI_UINT) + TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_UINT); +#else + #error "No ecp variant detected." +#endif +} +/* END_CASE */ From f4aab6f666c8569cd5ec3f4036092353e25db13e Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Fri, 30 Jun 2023 14:50:03 +0200 Subject: [PATCH 05/11] Add comments and remove unneeded defines For `check_names.py` it is enough to appear a macro definition in a comment to validate it. Signed-off-by: Gabor Mezei --- library/ecp_invasive.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 0a0d361d2..31fde48a2 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -40,11 +40,15 @@ typedef enum { MBEDTLS_ECP_MOD_SCALAR } mbedtls_ecp_modulus_type; +/* Requred macros for ECP split. + * If MBEDTLS_ECP_WITH_MPI_UINT is defined the new bignum interface is used. + */ #ifndef MBEDTLS_ECP_WITH_MPI_UINT -#define MBEDTLS_ECP_WITH_MPI_UINT -#undef MBEDTLS_ECP_WITH_MPI_UINT +/* Because of `check_names.py` a define is needed for every macro. */ +//#define MBEDTLS_ECP_WITH_MPI_UINT +/* Enable the old bignum interface. */ #define MBEDTLS_ECP_WITH_MPI_STRUCT #endif From d6789f1e2e8061c3d56457c2462b5fec08d61451 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Wed, 5 Jul 2023 16:08:22 +0200 Subject: [PATCH 06/11] Used preferred macro definition check Signed-off-by: Gabor Mezei --- library/ecp_invasive.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 31fde48a2..6c55b2945 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -43,7 +43,7 @@ typedef enum { /* Requred macros for ECP split. * If MBEDTLS_ECP_WITH_MPI_UINT is defined the new bignum interface is used. */ -#ifndef MBEDTLS_ECP_WITH_MPI_UINT +#if !defined(MBEDTLS_ECP_WITH_MPI_UINT) /* Because of `check_names.py` a define is needed for every macro. */ //#define MBEDTLS_ECP_WITH_MPI_UINT From 1a729dcecec564b9f21ea1d6e22bd59803fb2181 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Wed, 5 Jul 2023 16:08:57 +0200 Subject: [PATCH 07/11] Fix comment Signed-off-by: Gabor Mezei --- library/ecp_invasive.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 6c55b2945..456ac21c9 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -45,7 +45,12 @@ typedef enum { */ #if !defined(MBEDTLS_ECP_WITH_MPI_UINT) -/* Because of `check_names.py` a define is needed for every macro. */ +/* Provide a commented-out definition so that `check_names.py` knows that + * it's not a typo. + * MBEDTLS_ECP_WITH_MPI_UINT must not be defined within config files, but + * only on the command line, as otherwise both ECP implementations will be + * built. + */ //#define MBEDTLS_ECP_WITH_MPI_UINT /* Enable the old bignum interface. */ From 6db604711db6df1f9f41bdded93bb9a1eb8cb21e Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Wed, 5 Jul 2023 16:38:42 +0200 Subject: [PATCH 08/11] Add a new test component to test the new bignum interface with `TEST_HOOKS` Signed-off-by: Gabor Mezei --- tests/scripts/all.sh | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh index d2ea9b68f..622ec7b2a 100755 --- a/tests/scripts/all.sh +++ b/tests/scripts/all.sh @@ -1118,6 +1118,20 @@ component_test_full_cmake_gcc_asan_new_bignum () { full-libmbedx509-modules } +component_test_full_cmake_gcc_asan_new_bignum_test_hooks () { + msg "build: full config, cmake, gcc, ASan" + scripts/config.py full + scripts/config.py set MBEDTLS_TEST_HOOKS + CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan . + make CFLAGS="-DMBEDTLS_ECP_WITH_MPI_UINT" + + msg "test: main suites (inc. selftests) (full config, ASan build)" + make test + + msg "test: selftest (ASan build)" # ~ 10s + programs/test/selftest +} + component_test_psa_crypto_key_id_encodes_owner () { msg "build: full config + PSA_CRYPTO_KEY_ID_ENCODES_OWNER, cmake, gcc, ASan" scripts/config.py full From 2a7bcaf8af76afad5c8fe5e4854fd4fdd95e7868 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Thu, 6 Jul 2023 10:37:51 +0200 Subject: [PATCH 09/11] Use only `MBEDTLS_ECP_WITH_MPI_UINT` to switch between the ecp variants Signed-off-by: Gabor Mezei --- library/ecp.c | 7 +++---- library/ecp_invasive.h | 12 +----------- library/ecp_new.c | 3 +-- tests/suites/test_suite_ecp.function | 6 ++---- 4 files changed, 7 insertions(+), 21 deletions(-) diff --git a/library/ecp.c b/library/ecp.c index 60872567f..f5d43d5d6 100644 --- a/library/ecp.c +++ b/library/ecp.c @@ -43,9 +43,7 @@ #include "common.h" -#include "ecp_invasive.h" - -#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT) +#if !defined(MBEDTLS_ECP_WITH_MPI_UINT) /** * \brief Function level alternative implementation. @@ -84,6 +82,7 @@ #include "mbedtls/error.h" #include "bn_mul.h" +#include "ecp_invasive.h" #include @@ -3653,4 +3652,4 @@ mbedtls_ecp_variant mbedtls_ecp_get_variant() #endif /* MBEDTLS_ECP_LIGHT */ -#endif /* MBEDTLS_ECP_WITH_MPI_STRUCT */ +#endif /* MBEDTLS_ECP_WITH_MPI_UINT */ diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 456ac21c9..c4a0a4dd5 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -40,23 +40,13 @@ typedef enum { MBEDTLS_ECP_MOD_SCALAR } mbedtls_ecp_modulus_type; -/* Requred macros for ECP split. - * If MBEDTLS_ECP_WITH_MPI_UINT is defined the new bignum interface is used. - */ -#if !defined(MBEDTLS_ECP_WITH_MPI_UINT) - /* Provide a commented-out definition so that `check_names.py` knows that * it's not a typo. * MBEDTLS_ECP_WITH_MPI_UINT must not be defined within config files, but - * only on the command line, as otherwise both ECP implementations will be - * built. + * only on the command line. */ //#define MBEDTLS_ECP_WITH_MPI_UINT -/* Enable the old bignum interface. */ -#define MBEDTLS_ECP_WITH_MPI_STRUCT -#endif - typedef enum { MBEDTLS_ECP_VARIANT_NONE = 0, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT = 1, diff --git a/library/ecp_new.c b/library/ecp_new.c index 3df6f9f9c..028a33bfa 100644 --- a/library/ecp_new.c +++ b/library/ecp_new.c @@ -43,8 +43,6 @@ #include "common.h" -#include "ecp_invasive.h" - #if defined(MBEDTLS_ECP_WITH_MPI_UINT) /** @@ -84,6 +82,7 @@ #include "mbedtls/error.h" #include "bn_mul.h" +#include "ecp_invasive.h" #include diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function index 03bbab68f..0b4cd4b2a 100644 --- a/tests/suites/test_suite_ecp.function +++ b/tests/suites/test_suite_ecp.function @@ -1636,12 +1636,10 @@ void check_variant() { mbedtls_ecp_variant variant = mbedtls_ecp_get_variant(); -#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT) - TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT); -#elif defined(MBEDTLS_ECP_WITH_MPI_UINT) +#if defined(MBEDTLS_ECP_VARIANT_WITH_MPI_UINT) TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_UINT); #else - #error "No ecp variant detected." + TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT); #endif } /* END_CASE */ From c97a407dbaee59d1accce0b2544f33918be7d326 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Thu, 6 Jul 2023 10:54:41 +0200 Subject: [PATCH 10/11] Remove value assignment for enum entries Signed-off-by: Gabor Mezei --- library/ecp_invasive.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index c4a0a4dd5..047323e8f 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -48,9 +48,9 @@ typedef enum { //#define MBEDTLS_ECP_WITH_MPI_UINT typedef enum { - MBEDTLS_ECP_VARIANT_NONE = 0, - MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT = 1, - MBEDTLS_ECP_VARIANT_WITH_MPI_UINT = 2 + MBEDTLS_ECP_VARIANT_NONE = 0, + MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT, + MBEDTLS_ECP_VARIANT_WITH_MPI_UINT } mbedtls_ecp_variant; #if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_ECP_LIGHT) From f05ca737da2da1b8686dfc6357fa40e0e679bc20 Mon Sep 17 00:00:00 2001 From: Gabor Mezei Date: Fri, 7 Jul 2023 12:59:22 +0200 Subject: [PATCH 11/11] Update comment Signed-off-by: Gabor Mezei --- library/ecp_invasive.h | 2 -- 1 file changed, 2 deletions(-) diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h index 047323e8f..db9dee3f4 100644 --- a/library/ecp_invasive.h +++ b/library/ecp_invasive.h @@ -42,8 +42,6 @@ typedef enum { /* Provide a commented-out definition so that `check_names.py` knows that * it's not a typo. - * MBEDTLS_ECP_WITH_MPI_UINT must not be defined within config files, but - * only on the command line. */ //#define MBEDTLS_ECP_WITH_MPI_UINT