diff options
Diffstat (limited to 'rsa.c')
| -rw-r--r-- | rsa.c | 301 |
1 files changed, 257 insertions, 44 deletions
@@ -12,8 +12,9 @@ * St Denis's libtomcrypt code. * * Authors: Rob Austein - * Copyright (c) 2015-2018, NORDUnet A/S - * All rights reserved. + * Copyright (c) 2015-2018, NORDUnet A/S All rights reserved. + * Copyright: 2020, The Commons Conservancy Cryptech Project + * SPDX-License-Identifier: BSD-3-Clause * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are @@ -25,9 +26,9 @@ * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * - * - Neither the name of the NORDUnet nor the names of its contributors may - * be used to endorse or promote products derived from this software - * without specific prior written permission. + * - Neither the name of the copyright holder nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED @@ -121,6 +122,13 @@ void hal_rsa_set_debug(const int onoff) debug = onoff; } +static int do_crt = 1; + +void hal_rsa_set_crt(const int onoff) +{ + do_crt = onoff; +} + /* * Whether we want RSA blinding. */ @@ -146,6 +154,13 @@ static struct { #endif +void hal_rsa_clear_blinding_cache(void) +{ +#if HAL_RSA_BLINDING_CACHE_SIZE > 0 + memset(&bfc, 0, sizeof(bfc)); +#endif +} + /* * RSA key implementation. This structure type is private to this * module, anything else that needs to touch one of these just gets a @@ -165,9 +180,9 @@ struct hal_rsa_key { fp_int dQ[1]; /* d mod (q - 1) */ unsigned flags; /* Internal key flags */ uint8_t /* ModExpA7 speedup factors */ - nC[HAL_RSA_MAX_OPERAND_LENGTH], nF[HAL_RSA_MAX_OPERAND_LENGTH], - pC[HAL_RSA_MAX_OPERAND_LENGTH/2], pF[HAL_RSA_MAX_OPERAND_LENGTH/2], - qC[HAL_RSA_MAX_OPERAND_LENGTH/2], qF[HAL_RSA_MAX_OPERAND_LENGTH/2]; + nC[HAL_RSA_MAX_OPERAND_LENGTH+4], nF[HAL_RSA_MAX_OPERAND_LENGTH], + pC[HAL_RSA_MAX_OPERAND_LENGTH/2+4], pF[HAL_RSA_MAX_OPERAND_LENGTH/2], + qC[HAL_RSA_MAX_OPERAND_LENGTH/2+4], qF[HAL_RSA_MAX_OPERAND_LENGTH/2]; }; #define RSA_FLAG_NEEDS_SAVING (1 << 0) @@ -228,6 +243,26 @@ static hal_error_t unpack_fp(const fp_int * const bn, uint8_t *buffer, const siz #if HAL_RSA_SIGN_USE_MODEXP +static hal_error_t modexpng_precalc(const fp_int *modulus, uint8_t *coeff, size_t coeff_len, uint8_t *factor, size_t factor_len) +{ + const size_t keylen = ((fp_unsigned_bin_size(unconst_fp_int(modulus)) + 3) & ~3) * 8; + hal_error_t err; + + /* factor = (2 ** (2 * (keylen + 16))) % modulus */ + fp_int fp_result[1]; + fp_2expt(fp_result, 2 * (keylen + 16)); + fp_mod(fp_result, unconst_fp_int(modulus), fp_result); + if ((err = unpack_fp(fp_result, factor, factor_len)) != HAL_OK) + return err; + + /* coeff = (-modulus ** -1) % (2 ** (keylen + 16)) */ + fp_int pwr[1]; + fp_2expt(pwr, keylen + 16); + fp_neg(unconst_fp_int(modulus), fp_result); + fp_invmod(fp_result, pwr, fp_result); + return unpack_fp(fp_result, coeff, coeff_len); +} + /* * Unwrap bignums into byte arrays, feed them into hal_modexp(), and * wrap result back up as a bignum. @@ -248,14 +283,34 @@ static hal_error_t modexp(hal_core_t *core, return HAL_ERROR_IMPOSSIBLE; const size_t msg_len = (fp_unsigned_bin_size(unconst_fp_int(msg)) + 3) & ~3; - const size_t exp_len = (fp_unsigned_bin_size(unconst_fp_int(exp)) + 3) & ~3; - const size_t mod_len = (fp_unsigned_bin_size(unconst_fp_int(mod)) + 3) & ~3; + const size_t exp_len = (fp_unsigned_bin_size(unconst_fp_int(exp)) + 3) & ~3; + const size_t mod_len = (fp_unsigned_bin_size(unconst_fp_int(mod)) + 3) & ~3; uint8_t msgbuf[msg_len]; uint8_t expbuf[exp_len]; uint8_t modbuf[mod_len]; uint8_t resbuf[mod_len]; + if (hal_modexp_using_modexpng()) { + hal_modexpng_arg_t args = { + .core = core, + .msg = msgbuf, .msg_len = sizeof(msgbuf), + .exp = expbuf, .exp_len = sizeof(expbuf), + .mod = modbuf, .mod_len = sizeof(modbuf), + .result = resbuf, .result_len = sizeof(resbuf), + .coeff = coeff, .coeff_len = coeff_len, + .mont = mont, .mont_len = mont_len + }; + + if ((precalc && + (err = modexpng_precalc(mod, coeff, coeff_len, mont, mont_len)) != HAL_OK) || + (err = unpack_fp(msg, msgbuf, sizeof(msgbuf))) != HAL_OK || + (err = unpack_fp(exp, expbuf, sizeof(expbuf))) != HAL_OK || + (err = unpack_fp(mod, modbuf, sizeof(modbuf))) != HAL_OK || + (err = hal_modexpng(&args)) != HAL_OK) + goto fail; + } + else { hal_modexp_arg_t args = { .core = core, .msg = msgbuf, .msg_len = sizeof(msgbuf), @@ -266,11 +321,12 @@ static hal_error_t modexp(hal_core_t *core, .mont = mont, .mont_len = mont_len }; - if ((err = unpack_fp(msg, msgbuf, sizeof(msgbuf))) != HAL_OK || - (err = unpack_fp(exp, expbuf, sizeof(expbuf))) != HAL_OK || - (err = unpack_fp(mod, modbuf, sizeof(modbuf))) != HAL_OK || - (err = hal_modexp(precalc, &args)) != HAL_OK) + if ((err = unpack_fp(msg, msgbuf, sizeof(msgbuf))) != HAL_OK || + (err = unpack_fp(exp, expbuf, sizeof(expbuf))) != HAL_OK || + (err = unpack_fp(mod, modbuf, sizeof(modbuf))) != HAL_OK || + (err = hal_modexp(precalc, &args)) != HAL_OK) goto fail; + } fp_read_unsigned_bin(res, resbuf, sizeof(resbuf)); @@ -279,7 +335,6 @@ static hal_error_t modexp(hal_core_t *core, memset(expbuf, 0, sizeof(expbuf)); memset(modbuf, 0, sizeof(modbuf)); memset(resbuf, 0, sizeof(resbuf)); - memset(&args, 0, sizeof(args)); return err; } @@ -306,34 +361,34 @@ static hal_error_t modexp2(const int precalc, return HAL_ERROR_IMPOSSIBLE; const size_t msg_len = (fp_unsigned_bin_size(unconst_fp_int(msg)) + 3) & ~3; - const size_t exp1_len = (fp_unsigned_bin_size(unconst_fp_int(exp1)) + 3) & ~3; - const size_t mod1_len = (fp_unsigned_bin_size(unconst_fp_int(mod1)) + 3) & ~3; - const size_t exp2_len = (fp_unsigned_bin_size(unconst_fp_int(exp2)) + 3) & ~3; - const size_t mod2_len = (fp_unsigned_bin_size(unconst_fp_int(mod2)) + 3) & ~3; + const size_t exp1_len = (fp_unsigned_bin_size(unconst_fp_int(exp1)) + 3) & ~3; + const size_t mod1_len = (fp_unsigned_bin_size(unconst_fp_int(mod1)) + 3) & ~3; + const size_t exp2_len = (fp_unsigned_bin_size(unconst_fp_int(exp2)) + 3) & ~3; + const size_t mod2_len = (fp_unsigned_bin_size(unconst_fp_int(mod2)) + 3) & ~3; uint8_t msgbuf[msg_len]; uint8_t expbuf1[exp1_len], modbuf1[mod1_len], resbuf1[mod1_len]; uint8_t expbuf2[exp2_len], modbuf2[mod2_len], resbuf2[mod2_len]; - hal_modexp_arg_t args1 = { - .core = core1, - .msg = msgbuf, .msg_len = sizeof(msgbuf), - .exp = expbuf1, .exp_len = sizeof(expbuf1), - .mod = modbuf1, .mod_len = sizeof(modbuf1), - .result = resbuf1, .result_len = sizeof(resbuf1), - .coeff = coeff1, .coeff_len = coeff1_len, - .mont = mont1, .mont_len = mont1_len - }; - - hal_modexp_arg_t args2 = { - .core = core2, - .msg = msgbuf, .msg_len = sizeof(msgbuf), - .exp = expbuf2, .exp_len = sizeof(expbuf2), - .mod = modbuf2, .mod_len = sizeof(modbuf2), - .result = resbuf2, .result_len = sizeof(resbuf2), - .coeff = coeff2, .coeff_len = coeff2_len, - .mont = mont2, .mont_len = mont2_len - }; + hal_modexp_arg_t args1 = { + .core = core1, + .msg = msgbuf, .msg_len = sizeof(msgbuf), + .exp = expbuf1, .exp_len = sizeof(expbuf1), + .mod = modbuf1, .mod_len = sizeof(modbuf1), + .result = resbuf1, .result_len = sizeof(resbuf1), + .coeff = coeff1, .coeff_len = coeff1_len, + .mont = mont1, .mont_len = mont1_len + }; + + hal_modexp_arg_t args2 = { + .core = core2, + .msg = msgbuf, .msg_len = sizeof(msgbuf), + .exp = expbuf2, .exp_len = sizeof(expbuf2), + .mod = modbuf2, .mod_len = sizeof(modbuf2), + .result = resbuf2, .result_len = sizeof(resbuf2), + .coeff = coeff2, .coeff_len = coeff2_len, + .mont = mont2, .mont_len = mont2_len + }; if ((err = unpack_fp(msg, msgbuf, sizeof(msgbuf))) != HAL_OK || (err = unpack_fp(exp1, expbuf1, sizeof(expbuf1))) != HAL_OK || @@ -341,7 +396,7 @@ static hal_error_t modexp2(const int precalc, (err = unpack_fp(exp2, expbuf2, sizeof(expbuf2))) != HAL_OK || (err = unpack_fp(mod2, modbuf2, sizeof(modbuf2))) != HAL_OK || (err = hal_modexp2(precalc, &args1, &args2)) != HAL_OK) - goto fail; + goto fail; fp_read_unsigned_bin(res1, resbuf1, sizeof(resbuf1)); fp_read_unsigned_bin(res2, resbuf2, sizeof(resbuf2)); @@ -359,6 +414,113 @@ static hal_error_t modexp2(const int precalc, return err; } +static hal_error_t modexpng(hal_core_t *core, + const fp_int * const msg, + hal_rsa_key_t *key, + fp_int *bf, + fp_int *ubf, + fp_int *res) +{ + hal_error_t err = HAL_OK; + + if (msg == NULL || key == NULL || res == NULL) + return HAL_ERROR_IMPOSSIBLE; + + if (!(key->flags & RSA_FLAG_PRECALC_N_DONE)) { + if ((err = modexpng_precalc(key->n, key->nC, sizeof(key->nC), key->nF, sizeof(key->nF))) != HAL_OK) + return err; + key->flags |= RSA_FLAG_PRECALC_N_DONE | RSA_FLAG_NEEDS_SAVING; + } + + if (key->p && !(key->flags & RSA_FLAG_PRECALC_PQ_DONE)) { + if ((err = modexpng_precalc(key->p, key->pC, sizeof(key->pC), key->pF, sizeof(key->pF))) != HAL_OK || + (err = modexpng_precalc(key->q, key->qC, sizeof(key->qC), key->qF, sizeof(key->qF))) != HAL_OK) + return err; + key->flags |= RSA_FLAG_PRECALC_PQ_DONE | RSA_FLAG_NEEDS_SAVING; + } + +/* number of significant bytes in an fp_int, rounded to a multiple of 4 */ +#define fp_len(x) (fp_unsigned_bin_size(unconst_fp_int(x)) + 3) & ~3 + + const size_t mod_len = fp_len(key->n); + + uint8_t msgbuf[fp_len(msg)]; + uint8_t expbuf[fp_len(key->d)]; + uint8_t modbuf[mod_len]; + uint8_t resbuf[mod_len]; + uint8_t p_buf[mod_len/2]; + uint8_t q_buf[mod_len/2]; + uint8_t u_buf[mod_len/2]; + uint8_t dP_buf[mod_len/2]; + uint8_t dQ_buf[mod_len/2]; + uint8_t bf_buf[mod_len]; + uint8_t ubf_buf[mod_len]; + + hal_modexpng_arg_t args = { + .core = core, + .msg = msgbuf, .msg_len = sizeof(msgbuf), + .exp = expbuf, .exp_len = sizeof(expbuf), + .mod = modbuf, .mod_len = sizeof(modbuf), + .result = resbuf, .result_len = sizeof(resbuf), + .coeff = key->nC, .coeff_len = sizeof(key->nC), + .mont = key->nF, .mont_len = sizeof(key->nF), + .p = p_buf, .p_len = sizeof(p_buf), + .pC = key->pC, .pC_len = sizeof(key->pC), + .pF = key->pF, .pF_len = sizeof(key->pF), + .q = q_buf, .q_len = sizeof(q_buf), + .qC = key->qC, .qC_len = sizeof(key->qC), + .qF = key->qF, .qF_len = sizeof(key->qF), + .dP = dP_buf, .dP_len = sizeof(dP_buf), + .dQ = dQ_buf, .dQ_len = sizeof(dQ_buf), + .qInv = u_buf, .qInv_len = sizeof(u_buf), + .bf = bf_buf, .bf_len = sizeof(bf_buf), + .ubf = ubf_buf, .ubf_len = sizeof(ubf_buf), + }; + + if (bf) { + if ((err = unpack_fp(bf, bf_buf, sizeof(bf_buf))) != HAL_OK || + (err = unpack_fp(ubf, ubf_buf, sizeof(ubf_buf))) != HAL_OK) + goto fail; + } + else { + /* set blinding factors to (1,1) */ + memset(bf_buf, 0, sizeof(bf_buf)); bf_buf[sizeof(bf_buf) - 1] = 1; + memset(ubf_buf, 0, sizeof(ubf_buf)); ubf_buf[sizeof(ubf_buf) - 1] = 1; + } + + if ((err = unpack_fp(msg, msgbuf, sizeof(msgbuf))) != HAL_OK || + (err = unpack_fp(key->d, expbuf, sizeof(expbuf))) != HAL_OK || + (err = unpack_fp(key->n, modbuf, sizeof(modbuf))) != HAL_OK || + (err = unpack_fp(key->p, p_buf, sizeof(p_buf))) != HAL_OK || + (err = unpack_fp(key->q, q_buf, sizeof(q_buf))) != HAL_OK || + (err = unpack_fp(key->u, u_buf, sizeof(u_buf))) != HAL_OK || + (err = unpack_fp(key->dP, dP_buf, sizeof(dP_buf))) != HAL_OK || + (err = unpack_fp(key->dQ, dQ_buf, sizeof(dQ_buf))) != HAL_OK || + (err = hal_modexpng(&args)) != HAL_OK) + goto fail; + + fp_read_unsigned_bin(res, resbuf, sizeof(resbuf)); + /* we do the blinding factor mutation in create_blinding_factors, + * so we don't need to read them back from the core + */ + + fail: + memset(msgbuf, 0, sizeof(msgbuf)); + memset(expbuf, 0, sizeof(expbuf)); + memset(modbuf, 0, sizeof(modbuf)); + memset(resbuf, 0, sizeof(resbuf)); + memset(p_buf, 0, sizeof(p_buf)); + memset(q_buf, 0, sizeof(q_buf)); + memset(u_buf, 0, sizeof(u_buf)); + memset(dP_buf, 0, sizeof(dP_buf)); + memset(dQ_buf, 0, sizeof(dQ_buf)); + memset(bf_buf, 0, sizeof(bf_buf)); + memset(ubf_buf, 0, sizeof(ubf_buf)); + memset(&args, 0, sizeof(args)); + return err; +} + + #else /* HAL_RSA_SIGN_USE_MODEXP */ /* @@ -406,6 +568,25 @@ static hal_error_t modexp2(const int precalc, /* ignored */ return err; } +int hal_modexp_using_modexpng(void) +{ + return 0; +} + +static hal_error_t modexpng(hal_core_t *core, + const fp_int * const msg, + hal_rsa_key_t *key, + fp_int *bf, + fp_int *ubf, + fp_int *res) +{ + return HAL_ERROR_FORBIDDEN; +} + +static hal_error_t modexpng_precalc(const fp_int *modulus, uint8_t *coeff, const size_t coeff_len, uint8_t *factor, const size_t factor_len) +{ + return HAL_ERROR_FORBIDDEN; +} #endif /* HAL_RSA_SIGN_USE_MODEXP */ /* @@ -482,6 +663,7 @@ static hal_error_t create_blinding_factors(hal_rsa_key_t *key, fp_int *bf, fp_in fp_read_unsigned_bin(bf, rnd, sizeof(rnd)); fp_copy(bf, ubf); + /* bf = ubf ** e mod n */ if ((err = modexp(NULL, precalc, bf, key->e, key->n, bf, key->nC, sizeof(key->nC), key->nF, sizeof(key->nF))) != HAL_OK) goto fail; @@ -516,13 +698,25 @@ static hal_error_t rsa_crt(hal_core_t *core1, hal_core_t *core2, hal_rsa_key_t * if (key == NULL || msg == NULL || sig == NULL) return HAL_ERROR_IMPOSSIBLE; - const int precalc = !(key->flags & RSA_FLAG_PRECALC_PQ_DONE); hal_error_t err = HAL_OK; + fp_int bf[1] = INIT_FP_INT; + fp_int ubf[1] = INIT_FP_INT; + + if (hal_modexp_using_modexpng()) { + if (blinding) { + if ((err = create_blinding_factors(key, bf, ubf)) != HAL_OK) + return err; + return modexpng(core1, msg, key, bf, ubf, sig); + } + else { + return modexpng(core1, msg, key, NULL, NULL, sig); + } + } + + const int precalc = !(key->flags & RSA_FLAG_PRECALC_PQ_DONE); fp_int t[1] = INIT_FP_INT; fp_int m1[1] = INIT_FP_INT; fp_int m2[1] = INIT_FP_INT; - fp_int bf[1] = INIT_FP_INT; - fp_int ubf[1] = INIT_FP_INT; /* * Handle blinding if requested. @@ -530,6 +724,7 @@ static hal_error_t rsa_crt(hal_core_t *core1, hal_core_t *core2, hal_rsa_key_t * if (blinding) { if ((err = create_blinding_factors(key, bf, ubf)) != HAL_OK) goto fail; + /* msg = (msg * bf) % modulus */ FP_CHECK(fp_mulmod(msg, bf, unconst_fp_int(key->n), msg)); } @@ -571,6 +766,7 @@ static hal_error_t rsa_crt(hal_core_t *core1, hal_core_t *core2, hal_rsa_key_t * /* * Unblind if necessary. */ + /* sig = (sig * ubf) % modulus */ if (blinding) FP_CHECK(fp_mulmod(sig, ubf, unconst_fp_int(key->n), sig)); @@ -604,6 +800,7 @@ hal_error_t hal_rsa_encrypt(hal_core_t *core, fp_read_unsigned_bin(i, unconst_uint8_t(input), input_len); + /* o = i ** e % n */ err = modexp(core, precalc, i, key->e, key->n, o, key->nC, sizeof(key->nC), key->nF, sizeof(key->nF)); @@ -639,12 +836,18 @@ hal_error_t hal_rsa_decrypt(hal_core_t *core1, * just do brute force ModExp. */ - if (!fp_iszero(key->p) && !fp_iszero(key->q) && !fp_iszero(key->u) && - !fp_iszero(key->dP) && !fp_iszero(key->dQ)) + /* These should all be set if we generated the key, and we'll reject an + * externally generated key if it doesn't have all the components, so I'm + * not sure what the point is. + */ + if (do_crt && !fp_iszero(key->p) && !fp_iszero(key->q) && !fp_iszero(key->u) && + !fp_iszero(key->dP) && !fp_iszero(key->dQ)) { err = rsa_crt(core1, core2, key, i, o); + } else { const int precalc = !(key->flags & RSA_FLAG_PRECALC_N_DONE); + /* o = i ** d % n */ err = modexp(core1, precalc, i, key->d, key->n, o, key->nC, sizeof(key->nC), key->nF, sizeof(key->nF)); if (err == HAL_OK && precalc) @@ -706,6 +909,7 @@ static hal_error_t load_key(const hal_key_type_t type, switch (type) { case HAL_KEY_TYPE_RSA_PRIVATE: _(d); _(p); _(q); _(u); _(dP); _(dQ); + /* fall through */ case HAL_KEY_TYPE_RSA_PUBLIC: _(n); _(e); *key_ = key; @@ -977,6 +1181,15 @@ hal_error_t hal_rsa_key_gen(hal_core_t *core, key->flags |= RSA_FLAG_NEEDS_SAVING; +#if 0 + if (hal_modexp_using_modexpng()) { + modexpng_precalc(key->n, key->nC, sizeof(key->nC), key->nF, sizeof(key->nF)); + modexpng_precalc(key->p, key->pC, sizeof(key->pC), key->pF, sizeof(key->pF)); + modexpng_precalc(key->q, key->qC, sizeof(key->qC), key->qF, sizeof(key->qF)); + key->flags |= RSA_FLAG_PRECALC_N_DONE | RSA_FLAG_PRECALC_PQ_DONE; + } +#endif + *key_ = key; /* Fall through to cleanup */ |