| /** |
| * Modular bignum functions |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_ECP_WITH_MPI_UINT) |
| |
| #include <string.h> |
| |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/bignum.h" |
| |
| #include "mbedtls/platform.h" |
| |
| #include "bignum_core.h" |
| #include "bignum_mod.h" |
| #include "bignum_mod_raw.h" |
| #include "constant_time_internal.h" |
| |
| int mbedtls_mpi_mod_residue_setup(mbedtls_mpi_mod_residue *r, |
| const mbedtls_mpi_mod_modulus *N, |
| mbedtls_mpi_uint *p, |
| size_t p_limbs) |
| { |
| if (p_limbs != N->limbs || !mbedtls_mpi_core_lt_ct(p, N->p, N->limbs)) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| r->limbs = N->limbs; |
| r->p = p; |
| |
| return 0; |
| } |
| |
| void mbedtls_mpi_mod_residue_release(mbedtls_mpi_mod_residue *r) |
| { |
| if (r == NULL) { |
| return; |
| } |
| |
| r->limbs = 0; |
| r->p = NULL; |
| } |
| |
| void mbedtls_mpi_mod_modulus_init(mbedtls_mpi_mod_modulus *N) |
| { |
| if (N == NULL) { |
| return; |
| } |
| |
| N->p = NULL; |
| N->limbs = 0; |
| N->bits = 0; |
| N->int_rep = MBEDTLS_MPI_MOD_REP_INVALID; |
| } |
| |
| void mbedtls_mpi_mod_modulus_free(mbedtls_mpi_mod_modulus *N) |
| { |
| if (N == NULL) { |
| return; |
| } |
| |
| switch (N->int_rep) { |
| case MBEDTLS_MPI_MOD_REP_MONTGOMERY: |
| if (N->rep.mont.rr != NULL) { |
| mbedtls_zeroize_and_free((mbedtls_mpi_uint *) N->rep.mont.rr, |
| N->limbs * sizeof(mbedtls_mpi_uint)); |
| N->rep.mont.rr = NULL; |
| } |
| N->rep.mont.mm = 0; |
| break; |
| case MBEDTLS_MPI_MOD_REP_OPT_RED: |
| N->rep.ored.modp = NULL; |
| break; |
| case MBEDTLS_MPI_MOD_REP_INVALID: |
| break; |
| } |
| |
| N->p = NULL; |
| N->limbs = 0; |
| N->bits = 0; |
| N->int_rep = MBEDTLS_MPI_MOD_REP_INVALID; |
| } |
| |
| static int set_mont_const_square(const mbedtls_mpi_uint **X, |
| const mbedtls_mpi_uint *A, |
| size_t limbs) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_mpi N; |
| mbedtls_mpi RR; |
| *X = NULL; |
| |
| mbedtls_mpi_init(&N); |
| mbedtls_mpi_init(&RR); |
| |
| if (A == NULL || limbs == 0 || limbs >= (MBEDTLS_MPI_MAX_LIMBS / 2) - 2) { |
| goto cleanup; |
| } |
| |
| if (mbedtls_mpi_grow(&N, limbs)) { |
| goto cleanup; |
| } |
| |
| memcpy(N.p, A, sizeof(mbedtls_mpi_uint) * limbs); |
| |
| ret = mbedtls_mpi_core_get_mont_r2_unsafe(&RR, &N); |
| |
| if (ret == 0) { |
| *X = RR.p; |
| RR.p = NULL; |
| } |
| |
| cleanup: |
| mbedtls_mpi_free(&N); |
| mbedtls_mpi_free(&RR); |
| ret = (ret != 0) ? MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED : 0; |
| return ret; |
| } |
| |
| static inline void standard_modulus_setup(mbedtls_mpi_mod_modulus *N, |
| const mbedtls_mpi_uint *p, |
| size_t p_limbs, |
| mbedtls_mpi_mod_rep_selector int_rep) |
| { |
| N->p = p; |
| N->limbs = p_limbs; |
| N->bits = mbedtls_mpi_core_bitlen(p, p_limbs); |
| N->int_rep = int_rep; |
| } |
| |
| int mbedtls_mpi_mod_modulus_setup(mbedtls_mpi_mod_modulus *N, |
| const mbedtls_mpi_uint *p, |
| size_t p_limbs) |
| { |
| int ret = 0; |
| standard_modulus_setup(N, p, p_limbs, MBEDTLS_MPI_MOD_REP_MONTGOMERY); |
| N->rep.mont.mm = mbedtls_mpi_core_montmul_init(N->p); |
| ret = set_mont_const_square(&N->rep.mont.rr, N->p, N->limbs); |
| |
| if (ret != 0) { |
| mbedtls_mpi_mod_modulus_free(N); |
| } |
| |
| return ret; |
| } |
| |
| int mbedtls_mpi_mod_optred_modulus_setup(mbedtls_mpi_mod_modulus *N, |
| const mbedtls_mpi_uint *p, |
| size_t p_limbs, |
| mbedtls_mpi_modp_fn modp) |
| { |
| standard_modulus_setup(N, p, p_limbs, MBEDTLS_MPI_MOD_REP_OPT_RED); |
| N->rep.ored.modp = modp; |
| return 0; |
| } |
| |
| int mbedtls_mpi_mod_mul(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_residue *B, |
| const mbedtls_mpi_mod_modulus *N) |
| { |
| if (N->limbs == 0) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| if (X->limbs != N->limbs || A->limbs != N->limbs || B->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| mbedtls_mpi_uint *T = mbedtls_calloc(N->limbs * 2 + 1, ciL); |
| if (T == NULL) { |
| return MBEDTLS_ERR_MPI_ALLOC_FAILED; |
| } |
| |
| mbedtls_mpi_mod_raw_mul(X->p, A->p, B->p, N, T); |
| |
| mbedtls_free(T); |
| |
| return 0; |
| } |
| |
| int mbedtls_mpi_mod_sub(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_residue *B, |
| const mbedtls_mpi_mod_modulus *N) |
| { |
| if (X->limbs != N->limbs || A->limbs != N->limbs || B->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| mbedtls_mpi_mod_raw_sub(X->p, A->p, B->p, N); |
| |
| return 0; |
| } |
| |
| static int mbedtls_mpi_mod_inv_mont(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_modulus *N, |
| mbedtls_mpi_uint *working_memory) |
| { |
| /* Input already in Montgomery form, so there's little to do */ |
| mbedtls_mpi_mod_raw_inv_prime(X->p, A->p, |
| N->p, N->limbs, |
| N->rep.mont.rr, |
| working_memory); |
| return 0; |
| } |
| |
| static int mbedtls_mpi_mod_inv_non_mont(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_modulus *N, |
| mbedtls_mpi_uint *working_memory) |
| { |
| /* Need to convert input into Montgomery form */ |
| |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_mpi_mod_modulus Nmont; |
| mbedtls_mpi_mod_modulus_init(&Nmont); |
| |
| MBEDTLS_MPI_CHK(mbedtls_mpi_mod_modulus_setup(&Nmont, N->p, N->limbs)); |
| |
| /* We'll use X->p to hold the Montgomery form of the input A->p */ |
| mbedtls_mpi_core_to_mont_rep(X->p, A->p, Nmont.p, Nmont.limbs, |
| Nmont.rep.mont.mm, Nmont.rep.mont.rr, |
| working_memory); |
| |
| mbedtls_mpi_mod_raw_inv_prime(X->p, X->p, |
| Nmont.p, Nmont.limbs, |
| Nmont.rep.mont.rr, |
| working_memory); |
| |
| /* And convert back from Montgomery form */ |
| |
| mbedtls_mpi_core_from_mont_rep(X->p, X->p, Nmont.p, Nmont.limbs, |
| Nmont.rep.mont.mm, working_memory); |
| |
| cleanup: |
| mbedtls_mpi_mod_modulus_free(&Nmont); |
| return ret; |
| } |
| |
| int mbedtls_mpi_mod_inv(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_modulus *N) |
| { |
| if (X->limbs != N->limbs || A->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| /* Zero has the same value regardless of Montgomery form or not */ |
| if (mbedtls_mpi_core_check_zero_ct(A->p, A->limbs) == 0) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| size_t working_limbs = |
| mbedtls_mpi_mod_raw_inv_prime_working_limbs(N->limbs); |
| |
| mbedtls_mpi_uint *working_memory = mbedtls_calloc(working_limbs, |
| sizeof(mbedtls_mpi_uint)); |
| if (working_memory == NULL) { |
| return MBEDTLS_ERR_MPI_ALLOC_FAILED; |
| } |
| |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| switch (N->int_rep) { |
| case MBEDTLS_MPI_MOD_REP_MONTGOMERY: |
| ret = mbedtls_mpi_mod_inv_mont(X, A, N, working_memory); |
| break; |
| case MBEDTLS_MPI_MOD_REP_OPT_RED: |
| ret = mbedtls_mpi_mod_inv_non_mont(X, A, N, working_memory); |
| break; |
| default: |
| ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| break; |
| } |
| |
| mbedtls_zeroize_and_free(working_memory, |
| working_limbs * sizeof(mbedtls_mpi_uint)); |
| |
| return ret; |
| } |
| |
| int mbedtls_mpi_mod_add(mbedtls_mpi_mod_residue *X, |
| const mbedtls_mpi_mod_residue *A, |
| const mbedtls_mpi_mod_residue *B, |
| const mbedtls_mpi_mod_modulus *N) |
| { |
| if (X->limbs != N->limbs || A->limbs != N->limbs || B->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| mbedtls_mpi_mod_raw_add(X->p, A->p, B->p, N); |
| |
| return 0; |
| } |
| |
| int mbedtls_mpi_mod_random(mbedtls_mpi_mod_residue *X, |
| mbedtls_mpi_uint min, |
| const mbedtls_mpi_mod_modulus *N, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng) |
| { |
| if (X->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| return mbedtls_mpi_mod_raw_random(X->p, min, N, f_rng, p_rng); |
| } |
| |
| int mbedtls_mpi_mod_read(mbedtls_mpi_mod_residue *r, |
| const mbedtls_mpi_mod_modulus *N, |
| const unsigned char *buf, |
| size_t buflen, |
| mbedtls_mpi_mod_ext_rep ext_rep) |
| { |
| int ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| |
| /* Do our best to check if r and m have been set up */ |
| if (r->limbs == 0 || N->limbs == 0) { |
| goto cleanup; |
| } |
| if (r->limbs != N->limbs) { |
| goto cleanup; |
| } |
| |
| ret = mbedtls_mpi_mod_raw_read(r->p, N, buf, buflen, ext_rep); |
| if (ret != 0) { |
| goto cleanup; |
| } |
| |
| r->limbs = N->limbs; |
| |
| ret = mbedtls_mpi_mod_raw_canonical_to_modulus_rep(r->p, N); |
| |
| cleanup: |
| return ret; |
| } |
| |
| int mbedtls_mpi_mod_write(const mbedtls_mpi_mod_residue *r, |
| const mbedtls_mpi_mod_modulus *N, |
| unsigned char *buf, |
| size_t buflen, |
| mbedtls_mpi_mod_ext_rep ext_rep) |
| { |
| /* Do our best to check if r and m have been set up */ |
| if (r->limbs == 0 || N->limbs == 0) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| if (r->limbs != N->limbs) { |
| return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; |
| } |
| |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_mpi_uint *working_memory = r->p; |
| size_t working_memory_len = sizeof(mbedtls_mpi_uint) * r->limbs; |
| |
| if (N->int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY) { |
| |
| working_memory = mbedtls_calloc(r->limbs, sizeof(mbedtls_mpi_uint)); |
| |
| if (working_memory == NULL) { |
| ret = MBEDTLS_ERR_MPI_ALLOC_FAILED; |
| goto cleanup; |
| } |
| |
| memcpy(working_memory, r->p, working_memory_len); |
| |
| ret = mbedtls_mpi_mod_raw_from_mont_rep(working_memory, N); |
| if (ret != 0) { |
| goto cleanup; |
| } |
| } |
| |
| ret = mbedtls_mpi_mod_raw_write(working_memory, N, buf, buflen, ext_rep); |
| |
| cleanup: |
| |
| if (N->int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY && |
| working_memory != NULL) { |
| |
| mbedtls_zeroize_and_free(working_memory, working_memory_len); |
| } |
| |
| return ret; |
| } |
| |
| #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ECP_WITH_MPI_UINT */ |