|  | // SPDX-License-Identifier: GPL-2.0-or-later | 
|  | /* RSA asymmetric public-key algorithm [RFC3447] | 
|  | * | 
|  | * Copyright (c) 2015, Intel Corporation | 
|  | * Authors: Tadeusz Struk <tadeusz.struk@intel.com> | 
|  | */ | 
|  |  | 
|  | #include <linux/fips.h> | 
|  | #include <linux/module.h> | 
|  | #include <linux/mpi.h> | 
|  | #include <crypto/internal/rsa.h> | 
|  | #include <crypto/internal/akcipher.h> | 
|  | #include <crypto/akcipher.h> | 
|  | #include <crypto/algapi.h> | 
|  |  | 
|  | struct rsa_mpi_key { | 
|  | MPI n; | 
|  | MPI e; | 
|  | MPI d; | 
|  | MPI p; | 
|  | MPI q; | 
|  | MPI dp; | 
|  | MPI dq; | 
|  | MPI qinv; | 
|  | }; | 
|  |  | 
|  | static int rsa_check_payload(MPI x, MPI n) | 
|  | { | 
|  | MPI n1; | 
|  |  | 
|  | if (mpi_cmp_ui(x, 1) <= 0) | 
|  | return -EINVAL; | 
|  |  | 
|  | n1 = mpi_alloc(0); | 
|  | if (!n1) | 
|  | return -ENOMEM; | 
|  |  | 
|  | if (mpi_sub_ui(n1, n, 1) || mpi_cmp(x, n1) >= 0) { | 
|  | mpi_free(n1); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | mpi_free(n1); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * RSAEP function [RFC3447 sec 5.1.1] | 
|  | * c = m^e mod n; | 
|  | */ | 
|  | static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m) | 
|  | { | 
|  | /* | 
|  | * Even though (1) in RFC3447 only requires 0 <= m <= n - 1, we are | 
|  | * slightly more conservative and require 1 < m < n - 1. This is in line | 
|  | * with SP 800-56Br2, Section 7.1.1. | 
|  | */ | 
|  | if (rsa_check_payload(m, key->n)) | 
|  | return -EINVAL; | 
|  |  | 
|  | /* (2) c = m^e mod n */ | 
|  | return mpi_powm(c, m, key->e, key->n); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * RSADP function [RFC3447 sec 5.1.2] | 
|  | * m_1 = c^dP mod p; | 
|  | * m_2 = c^dQ mod q; | 
|  | * h = (m_1 - m_2) * qInv mod p; | 
|  | * m = m_2 + q * h; | 
|  | */ | 
|  | static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c) | 
|  | { | 
|  | MPI m2, m12_or_qh; | 
|  | int ret = -ENOMEM; | 
|  |  | 
|  | /* | 
|  | * Even though (1) in RFC3447 only requires 0 <= c <= n - 1, we are | 
|  | * slightly more conservative and require 1 < c < n - 1. This is in line | 
|  | * with SP 800-56Br2, Section 7.1.2. | 
|  | */ | 
|  | if (rsa_check_payload(c, key->n)) | 
|  | return -EINVAL; | 
|  |  | 
|  | m2 = mpi_alloc(0); | 
|  | m12_or_qh = mpi_alloc(0); | 
|  | if (!m2 || !m12_or_qh) | 
|  | goto err_free_mpi; | 
|  |  | 
|  | /* (2i) m_1 = c^dP mod p */ | 
|  | ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p); | 
|  | if (ret) | 
|  | goto err_free_mpi; | 
|  |  | 
|  | /* (2i) m_2 = c^dQ mod q */ | 
|  | ret = mpi_powm(m2, c, key->dq, key->q); | 
|  | if (ret) | 
|  | goto err_free_mpi; | 
|  |  | 
|  | /* (2iii) h = (m_1 - m_2) * qInv mod p */ | 
|  | ret = mpi_sub(m12_or_qh, m_or_m1_or_h, m2) ?: | 
|  | mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p); | 
|  |  | 
|  | /* (2iv) m = m_2 + q * h */ | 
|  | ret = ret ?: | 
|  | mpi_mul(m12_or_qh, key->q, m_or_m1_or_h) ?: | 
|  | mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n); | 
|  |  | 
|  | err_free_mpi: | 
|  | mpi_free(m12_or_qh); | 
|  | mpi_free(m2); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm) | 
|  | { | 
|  | return akcipher_tfm_ctx(tfm); | 
|  | } | 
|  |  | 
|  | static int rsa_enc(struct akcipher_request *req) | 
|  | { | 
|  | struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); | 
|  | const struct rsa_mpi_key *pkey = rsa_get_key(tfm); | 
|  | MPI m, c = mpi_alloc(0); | 
|  | int ret = 0; | 
|  | int sign; | 
|  |  | 
|  | if (!c) | 
|  | return -ENOMEM; | 
|  |  | 
|  | if (unlikely(!pkey->n || !pkey->e)) { | 
|  | ret = -EINVAL; | 
|  | goto err_free_c; | 
|  | } | 
|  |  | 
|  | ret = -ENOMEM; | 
|  | m = mpi_read_raw_from_sgl(req->src, req->src_len); | 
|  | if (!m) | 
|  | goto err_free_c; | 
|  |  | 
|  | ret = _rsa_enc(pkey, c, m); | 
|  | if (ret) | 
|  | goto err_free_m; | 
|  |  | 
|  | ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign); | 
|  | if (ret) | 
|  | goto err_free_m; | 
|  |  | 
|  | if (sign < 0) | 
|  | ret = -EBADMSG; | 
|  |  | 
|  | err_free_m: | 
|  | mpi_free(m); | 
|  | err_free_c: | 
|  | mpi_free(c); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | static int rsa_dec(struct akcipher_request *req) | 
|  | { | 
|  | struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req); | 
|  | const struct rsa_mpi_key *pkey = rsa_get_key(tfm); | 
|  | MPI c, m = mpi_alloc(0); | 
|  | int ret = 0; | 
|  | int sign; | 
|  |  | 
|  | if (!m) | 
|  | return -ENOMEM; | 
|  |  | 
|  | if (unlikely(!pkey->n || !pkey->d)) { | 
|  | ret = -EINVAL; | 
|  | goto err_free_m; | 
|  | } | 
|  |  | 
|  | ret = -ENOMEM; | 
|  | c = mpi_read_raw_from_sgl(req->src, req->src_len); | 
|  | if (!c) | 
|  | goto err_free_m; | 
|  |  | 
|  | ret = _rsa_dec_crt(pkey, m, c); | 
|  | if (ret) | 
|  | goto err_free_c; | 
|  |  | 
|  | ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign); | 
|  | if (ret) | 
|  | goto err_free_c; | 
|  |  | 
|  | if (sign < 0) | 
|  | ret = -EBADMSG; | 
|  | err_free_c: | 
|  | mpi_free(c); | 
|  | err_free_m: | 
|  | mpi_free(m); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | static void rsa_free_mpi_key(struct rsa_mpi_key *key) | 
|  | { | 
|  | mpi_free(key->d); | 
|  | mpi_free(key->e); | 
|  | mpi_free(key->n); | 
|  | mpi_free(key->p); | 
|  | mpi_free(key->q); | 
|  | mpi_free(key->dp); | 
|  | mpi_free(key->dq); | 
|  | mpi_free(key->qinv); | 
|  | key->d = NULL; | 
|  | key->e = NULL; | 
|  | key->n = NULL; | 
|  | key->p = NULL; | 
|  | key->q = NULL; | 
|  | key->dp = NULL; | 
|  | key->dq = NULL; | 
|  | key->qinv = NULL; | 
|  | } | 
|  |  | 
|  | static int rsa_check_key_length(unsigned int len) | 
|  | { | 
|  | switch (len) { | 
|  | case 512: | 
|  | case 1024: | 
|  | case 1536: | 
|  | if (fips_enabled) | 
|  | return -EINVAL; | 
|  | fallthrough; | 
|  | case 2048: | 
|  | case 3072: | 
|  | case 4096: | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | static int rsa_check_exponent_fips(MPI e) | 
|  | { | 
|  | MPI e_max = NULL; | 
|  | int err; | 
|  |  | 
|  | /* check if odd */ | 
|  | if (!mpi_test_bit(e, 0)) { | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | /* check if 2^16 < e < 2^256. */ | 
|  | if (mpi_cmp_ui(e, 65536) <= 0) { | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | e_max = mpi_alloc(0); | 
|  | if (!e_max) | 
|  | return -ENOMEM; | 
|  |  | 
|  | err = mpi_set_bit(e_max, 256); | 
|  | if (err) { | 
|  | mpi_free(e_max); | 
|  | return err; | 
|  | } | 
|  |  | 
|  | if (mpi_cmp(e, e_max) >= 0) { | 
|  | mpi_free(e_max); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | mpi_free(e_max); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, | 
|  | unsigned int keylen) | 
|  | { | 
|  | struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); | 
|  | struct rsa_key raw_key = {0}; | 
|  | int ret; | 
|  |  | 
|  | /* Free the old MPI key if any */ | 
|  | rsa_free_mpi_key(mpi_key); | 
|  |  | 
|  | ret = rsa_parse_pub_key(&raw_key, key, keylen); | 
|  | if (ret) | 
|  | return ret; | 
|  |  | 
|  | mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); | 
|  | if (!mpi_key->e) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); | 
|  | if (!mpi_key->n) | 
|  | goto err; | 
|  |  | 
|  | if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) { | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | err: | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -ENOMEM; | 
|  | } | 
|  |  | 
|  | static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key, | 
|  | unsigned int keylen) | 
|  | { | 
|  | struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm); | 
|  | struct rsa_key raw_key = {0}; | 
|  | int ret; | 
|  |  | 
|  | /* Free the old MPI key if any */ | 
|  | rsa_free_mpi_key(mpi_key); | 
|  |  | 
|  | ret = rsa_parse_priv_key(&raw_key, key, keylen); | 
|  | if (ret) | 
|  | return ret; | 
|  |  | 
|  | mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz); | 
|  | if (!mpi_key->d) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz); | 
|  | if (!mpi_key->e) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz); | 
|  | if (!mpi_key->n) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz); | 
|  | if (!mpi_key->p) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz); | 
|  | if (!mpi_key->q) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz); | 
|  | if (!mpi_key->dp) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz); | 
|  | if (!mpi_key->dq) | 
|  | goto err; | 
|  |  | 
|  | mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz); | 
|  | if (!mpi_key->qinv) | 
|  | goto err; | 
|  |  | 
|  | if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) { | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) { | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -EINVAL; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | err: | 
|  | rsa_free_mpi_key(mpi_key); | 
|  | return -ENOMEM; | 
|  | } | 
|  |  | 
|  | static unsigned int rsa_max_size(struct crypto_akcipher *tfm) | 
|  | { | 
|  | struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); | 
|  |  | 
|  | return mpi_get_size(pkey->n); | 
|  | } | 
|  |  | 
|  | static void rsa_exit_tfm(struct crypto_akcipher *tfm) | 
|  | { | 
|  | struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm); | 
|  |  | 
|  | rsa_free_mpi_key(pkey); | 
|  | } | 
|  |  | 
|  | static struct akcipher_alg rsa = { | 
|  | .encrypt = rsa_enc, | 
|  | .decrypt = rsa_dec, | 
|  | .set_priv_key = rsa_set_priv_key, | 
|  | .set_pub_key = rsa_set_pub_key, | 
|  | .max_size = rsa_max_size, | 
|  | .exit = rsa_exit_tfm, | 
|  | .base = { | 
|  | .cra_name = "rsa", | 
|  | .cra_driver_name = "rsa-generic", | 
|  | .cra_priority = 100, | 
|  | .cra_module = THIS_MODULE, | 
|  | .cra_ctxsize = sizeof(struct rsa_mpi_key), | 
|  | }, | 
|  | }; | 
|  |  | 
|  | static int __init rsa_init(void) | 
|  | { | 
|  | int err; | 
|  |  | 
|  | err = crypto_register_akcipher(&rsa); | 
|  | if (err) | 
|  | return err; | 
|  |  | 
|  | err = crypto_register_template(&rsa_pkcs1pad_tmpl); | 
|  | if (err) | 
|  | goto err_unregister_rsa; | 
|  |  | 
|  | err = crypto_register_template(&rsassa_pkcs1_tmpl); | 
|  | if (err) | 
|  | goto err_unregister_rsa_pkcs1pad; | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | err_unregister_rsa_pkcs1pad: | 
|  | crypto_unregister_template(&rsa_pkcs1pad_tmpl); | 
|  | err_unregister_rsa: | 
|  | crypto_unregister_akcipher(&rsa); | 
|  | return err; | 
|  | } | 
|  |  | 
|  | static void __exit rsa_exit(void) | 
|  | { | 
|  | crypto_unregister_template(&rsassa_pkcs1_tmpl); | 
|  | crypto_unregister_template(&rsa_pkcs1pad_tmpl); | 
|  | crypto_unregister_akcipher(&rsa); | 
|  | } | 
|  |  | 
|  | module_init(rsa_init); | 
|  | module_exit(rsa_exit); | 
|  | MODULE_ALIAS_CRYPTO("rsa"); | 
|  | MODULE_LICENSE("GPL"); | 
|  | MODULE_DESCRIPTION("RSA generic algorithm"); |